Search results for: Pb resistant bacteria

Authors: Eleni Stefanidou, Nikolaos Katsenios, Ioanna Karamichali, Aspasia Efthimiadou, Panagiotis Madesis

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The excessive use of pesticides and fertilizers has significant environmental and human health-related negative effects. In the frame of the development of sustainable agriculture practices, especially in the context of extreme environmental changes (climate change), it is important to develop alternative practices to increase productivity and biotic and abiotic stress tolerance. Beneficial bacteria, such as symbiotic bacteria in legumes (rhizobia) and symbiotic or free-living Plant Growth Promoting Rhizobacteria (PGPR), which could act as "plant probiotics", can promote plant growth and significantly increase the resistance of crops under adverse environmental conditions. In this study, we explored the symbiotic relationships between Faba bean (Vicia faba L.) cultivars with different PGPR bacteria, aiming to identify the possible influence on yield and biotic-abiotic phytoprotection benefits. Transcriptomic analysis of root and whole plant samples was executed for two Vicia faba L. cultivars (Polikarpi and Solon) treated with selected PGPR bacteria (6 treatments: B. subtilis + Rhizobium-mixture, A. chroococcum + Rhizobium-mixture, B. subtilis, A. chroococcum and Rhizobium-mixture). Preliminary results indicate a significant yield (Seed weight and Total number of pods) increase in both varieties, ranging around 25%, in comparison to the control, especially for the Solon cultivar. The increase was observed for all treatments, with the B. subtilis + Rhizobium-mixture treatment being the highest performing. The correlation of the physiological and morphological data with the transcriptome analysis revealed molecular mechanisms and molecular targets underlying the observed yield increase, opening perspectives for the use of nitrogen-fixing bacteria as a natural, more ecological enhancer of legume crop productivity.

Keywords: plant probiotics, PGPR, legumes, sustainable agriculture

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Authors: Bi Yan-Qiang, Shang Yonghong, Lin Boying, Ji Xinyan, Li Xiyuan

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The heat-resistant material has important application in the aerospace field. The reliability of the connection between the heat-resisting material and the body determines the success or failure of the project. In this paper, lock-in infrared thermography non-destructive testing technology is used to detect the stability of the thermal-resistant structure. The phase relationship between the temperature and the heat flow is calculated by the numerical method, and the influence of the heating frequency and power is obtained. The correctness of the analysis is verified by the experimental method. Through the research, it can provide the basis for the parameter setting of heat flux including frequency and power, improve the efficiency of detection and the reliability of connection between the heat-resisting material and the body.

Keywords: infrared non-destructive, thermal insulation material, reliability, connection

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Authors: Mohammad Khalid, Mariya Munir, Jacelyn Rice Boyaue

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Highways are considered a major source of pollution to storm-water, and its runoff can introduce various contaminants, including nutrients, Indicator bacteria, heavy metals, chloride, and phosphorus compounds, which can have negative impacts on receiving waters. This study assessed the ability of biochar for contaminants removal and to improve the water holding capacity of soil biochar mixture. For this, ten commercially available biochar has been strategically selected. Lab scale batch testing was done at 3% and 6% by the weight of the soil to find the preliminary estimate of contaminants removal along with hydraulic conductivity and water retention capacity. Furthermore, from the above-conducted studies, six best performing candidate and an application rate of 6% has been selected for the column studies. Soil biochar mixture was filled in 7.62 cm assembled columns up to a fixed height of 76.2 cm based on hydraulic conductivity. A total of eight column experiments have been conducted for nutrient, heavy metal, and indicator bacteria analysis over a period of one year, which includes a drying as well as a deicing period. The saturated hydraulic conductivity was greatly improved, which is attributed to the high porosity of the biochar soil mixture. Initial data from the column testing shows that biochar may have the ability to significantly remove nutrients, indicator bacteria, and heavy metals. The overall study demonstrates that biochar could be efficiently applied with clay soil to improve the soil's hydraulic characteristics as well as remove the pollutants from the stormwater runoff.

Keywords: biochar, nutrients, indicator bacteria, storm-water treatment, sustainability

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Authors: Marina Nisnevitch, Anton Valkov, Faina Nakonechny, Kate Adar Raik, Yamit Mualem

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Photosensitizers are dye compounds belonging to various chemical groups that in all the cases have a developed structure of conjugated double bonds. Under illumination with visible light, the photosensitizers are excited and transfer the absorbed energy to the oxygen dissolved in an aqueous phase, leading to production of a reactive oxygen species which cause irreversible damage to bacterial cells. When immobilized onto a solid phase, photosensitizers preserve their antibacterial properties. In the present study, photosensitizers were immobilized in polyethylene or propylene and tested for antimicrobial activity against Gram-positive S. aureus, S. epidermidis and Streptococcus sp. For this purpose, water-soluble photosensitizers, Rose Bengal sodium salt, and methylene blue as well as water-insoluble hematoporphyrin and Rose Bengal lactone, were immobilized by dissolution in melted polymers to yield 3 mm diameter rods and 3-5 mm beads. All four photosensitizers were found to be effective in the eradication of Gram-positive bacteria under illumination by a white luminescent lamp or sunlight. The immobilized photosensitizers can be applied for continuous water disinfection; they can be easily removed at the end of the treatment and reused.

Keywords: antimicrobial polymers, gram-positive bacteria, immobilization of photosensitizers, photodynamic antibacterial activity

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Authors: Kraiem Khadija, Hamadi Kallali, Naceur Jedidi

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Constructed wetland systems are eco-technology recognized as environmentally friendly and emerging innovative solutions remediation as these systems are cost-effective and sustainable wastewater treatment systems. The performance of these biological system is affected by various factors such as plant, substrate, wastewater type, hydraulic loading rate, hydraulic retention time, water depth, and operation mood. The objective of this study was to to assess the alters of plant species on pollutants reduction and enrichment of anammox and nitrifing denitrifing bacteria in a modified vertical flow (VFCW) constructed wetland. This tests were carried out using three modified vertical constructed wetlands with a surface of 0.23 m² and depth 80 cm. It was a saturated vertical constructed wetland at the bottom. The saturation zone is maintained by the siphon structure at the outlet. The VFCW (₁) system was unplanted, VFCW (₂) planted with Typha angustofolia, and VFCW(₃) planted with Phragmites australis. The experimental units were fed with domestic wastewater and were operated by batch mode during 8 months at an average hydraulic loading rate around 20 cm day− 1. The operation cycle was two days feeding and five days rest. Results indicated that plants presence improved the removal efficiency; the removal rates of organic matter (85.1–90.9%; COD and 81.8–88.9%; BOD5), nitrogen (54.2–73%; NTK and 66–77%; NH4 -N) were higher by 10.7–30.1% compared to the unplanted vertical constructed wetland. On the other hand, the plant species had no significant effect on removal efficiency of COD, The removal of COD was similar in VFCW (₂) and VFCW (₃) (p > 0.05), attaining average removal efficiencies of 88.7% and 85.2%, respectively. Whereas it had a significant effect on NTK removal (p > 0.05), with an average removal rate of 72% versus 51% for VFCW (₂) and VFCW (₃), respectively. Among the three sets of vertical flow constructed wetlands, the VFCW(₂) removed the highest percent of total streptococcus, fecal streptococcus total coliforms, fecal coliforms, E. coli as 59, 62, 52, 63, and 58%, respectively. The presence and the plant species alters the community composition and abundance of the bacteria. The abundance of bacteria in the planted wetland was much higher than that in the unplanted one. VFCW(₃) had the highest relative abundance of nitrifying bacteria such as Nitrosospira (18%), Nitrosospira (12%), and Nitrobacter (8%). Whereas the vertical constructed wetland planted with typha had larger number of denitrifying species, with relative abundances of Aeromonas (13%), Paracoccus (11%), Thauera (7%), and Thiobacillus (6%). However, the abundance of nitrifying bacteria was very lower in this system than VFCW(₂). Interestingly, the presence of Thypha angustofolia species favored the enrichment of anammox bacteria compared to unplanted system and system planted with phragmites australis. The results showed that the middle layer had the most accumulation of anammox bacteria, which the anaerobic condition is better and the root system is moderate. Vegetation has several characteristics that make it an essential component of wetlands, but its exact effects are complex and debated.

Keywords: wastawater, constructed wetland, anammox, removal

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Authors: Alaa A. Youssef, Mohamed A. El-Emam, Momeana B. Mahmoud, Mona Ragheb

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Schistosomiasis, also known as bilharzia, is a disease caused by a parasitic trematode worm called Schistosoma. Biological control of the snail intermediate hosts of Schistosoma is one of the promising methods for eliminating this disease in Egypt. The molluscicidal activity of exotoxins secreted from Bacillus subtilis bacteria was studied. The effect of these exotoxins was studied on the fecundity of Biomphalaria alexandrina snails the intermediate host of Schistosoma mansoni; the fecundity includes the reproductive rate (R0) of B. alexandrina snails and levels of sex hormones (progesterone, testosterone, and estradiol). Moreover, the cercarial production of S. mansoni was determined. The results showed a significant reduction in the egg-laying capacity of the treated snails after exposure to sublethal concentrations ( LC10 and LC25) of B. Subtilis exotoxins; this reduction reached 70% at LC25. Moreover, B. Subtilis exotoxins' significantly suppressed the cercarial production of B. alexandrina snails. It is concluded that the exotoxins of Bacillus subtilis bacteria play an important role in the interference of the Schistosomiasis transmission, hence should be applied in the strategy of schistosomiasis control.

Keywords: schistosomiasis, Biomphalaria alexandrina snails, Bacillus subtilis bacteria, fecundity, sex hormones

Procedia PDF Downloads 124

Authors: Shaghayegh Rafatpanah, Mehrnaz Rad, Ahmad Reza Movassaghi, Javad Khoshnegah

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The purpose of the present study was to investigate the prevalence of isolation, antimicrobial susceptibility and ERIC-PCR typing of staphylococci species from dogs with pyoderma. The study animals were 61 clinical cases of Iranian domestic dogs with the first-time pyoderma. The prevalence of pyoderma was significantly higher amongst adult (odds Ratio: 0.21; p=0.001) large breed (odds Ratio: 2.42; p=0.002)dogs. There was no difference in prevalence of pyoderma in male and females (odds Ratio: 1.27; p= 0.337). The 'head, face and pinna' and 'trunk' were the most affected lesion regions, each with 19 cases (26.76%). An identifiable underlying disease was present in 52 (85.24%) of the dogs. Bacterial species were recovered from 43 of the 61 (70.49%) studied animals. No isolates were recovered from 18 studied dogs. The most frequently recovered bacterial genus was Staphylococcus (32/43 isolates, 74.41%) including S. epidermidis (22/43 isolates, 51.16%), S. aureus (7/43 isolates, 16.27%) and S. pseudintermedius (3/43 isolates, 6.97%). Staphylococci species resistance was most commonly seen against amoxicillin (94.11%), penicillin (83.35%), and ampicillin (76.47%). Resistant to cephalexin and cefoxitin was 5.88% and 2.94%, respectively. A total of 27 of the staphylococci isolated (84.37 %) were resistant to at least one antimicrobial agent, and 19 isolates (59.37%) were resistant to three or more antimicrobial drugs. There were no significant differences in the prevalence of resistance between the staphylococci isolated from cases of superficial and deep pyoderma. ERIC-PCR results revealed 19 different patterns among 22 isolates of S. epidermidis and 7 isolates of S. aureus.

Keywords: dog, pyoderma, Staphylococcus, Staphylococcus epidermidis, Iran

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Authors: R. Frikha, H. Kamoun

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Background:Chronicmyeloidleukemia (CML), a hematologicaldisease, ischaracterized by t (9; 22) and relatedoncogene BCR-ABL formation. Although Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of CML, resistanceoccurs and possibly médiates by mutation in severalgenesindependently of the bcr-abl1 kinase mechanism. it has been reportedthat JAK2V617F/BCR-ABL double positivitymaybe a potential marker of resistance in CML. Aims: This studywasinvestigated the JAK2V617F mutation in TKI-resistant CML patients. Methods: A retrospectivestudywasconducted in the Hospital University of Sfax, south of Tunisia, including all CML TKI-resistant patients. A Sanger sequencingwasperformedusing a high-fidelity DNA polymerase. Results:Nineresistant CP-CML patients wereenrolled in thisstudy. The JAK2V617F mutation wasdetectedin 3 patients with TKI resistance. Conclusion:Despite the limit of ourstudy, ourfinding highlights the high frequency of JAK2V617F/BCR-ABL double positivity as an important marker of resistance. So; the combination of JAK and TKI inhibitorsmightbe effective and potentiallybeguided by molecular monitoring of minimal residual disease1.

Keywords: chronic myeloid leukemia, tyrosine kinase inhibitors, resistance, JAK2V617F, BCR-ABL

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Authors: Prittesh Patel, Bhavika Patel, Ramar Krishnamurthy

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Present study was conducted to isolate lactic acid bacteria (LAB) from Oreochromis niloticus and Nemipterus japonicus fish gut. The LAB isolated were confirmed through 16s rRNA sequencing. It was observed that isolated Lactococcus spp. were able to tolerate NaCl and bile acid up to certain range. The isolated Lactococcus spp. were also able to survive in acidic and alkaline conditions. Further agro-industrial waste like peels of pineapple, orange, lemon, sugarcane, pomegranate; sweet lemon was analyzed for their polysaccharide contents and prebiotic properties. In the present study, orange peels, sweet lemon peels, and pineapple peels give maximum indigestible polysaccharide. To evaluate synbiotic effect combination of probiotic and prebiotic were analyzed under in vitro conditions. Isolates Lactococcus garvieae R3 and Lactococcus sp. R4 reported to have better fermentation efficiency with orange, sweet lemon and pineapple compare to lemon, sugarcane and pomegranate. The different agro-industrial waste evaluated in this research resulted in being a cheap and fermentable carbon source by LAB.

Keywords: agro-industrial waste, lactic acid bacteria, prebiotic, probiotic, synbiotic

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Authors: Ekemini M. Okon, Reuben C. Okocha, Babatunde T. Adesina, Judith O. Ehigie, Babatunde M. Falana, Boluwape T. Okikiola

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Antimicrobial resistance (AMR) has evolved to become a significant threat to global public health and food safety. The development of AMR in animals has been associated with antimicrobial overuse. In recent years, the number of antimicrobials used in food animals such as fish and poultry has escalated. It, therefore, becomes imperative to understand the patterns of AMR in fish and poultry and map out future directions for better surveillance efforts. This study used the Preferred Reporting Items for Systematic reviews and Meta-Analyses(PRISMA) to assess the trend, patterns, and spatial distribution for AMR research in Egypt, Nigeria, and South Africa. A literature search was conducted through the Scopus and Web of Science databases in which published studies on AMR between 1989 and 2021 were assessed. A total of 172 articles were relevant for this study. The result showed progressive attention on AMR studies in fish and poultry from 2018 to 2021 across the selected countries. The period between 2018 (23 studies) and 2021 (25 studies) showed a significant increase in AMR publications with a peak in 2019 (28 studies). Egypt was the leading exponent of AMR research (43%, n=74) followed by Nigeria (40%, n=69), then South Africa (17%, n=29). AMR studies in fish received relatively little attention across countries. The majority of the AMR studies were on poultry in Egypt (82%, n=61), Nigeria (87%, n=60), and South Africa (83%, n=24). Further, most of the studies were on Escherichia and Salmonella species. Antimicrobials frequently researched were ampicillin, erythromycin, tetracycline, trimethoprim, chloramphenicol, and sulfamethoxazole groups. Multiple drug resistance was prevalent, as demonstrated by antimicrobial resistance patterns. In poultry, Escherichia coli isolates were resistant to cefotaxime, streptomycin, chloramphenicol, enrofloxacin, gentamycin, ciprofloxacin, oxytetracycline, kanamycin, nalidixic acid, tetracycline, trimethoprim/sulphamethoxazole, erythromycin, and ampicillin. Salmonella enterica serovars were resistant to tetracycline, trimethoprim/sulphamethoxazole, cefotaxime, and ampicillin. Staphylococcusaureus showed high-level resistance to streptomycin, kanamycin, erythromycin, cefoxitin, trimethoprim, vancomycin, ampicillin, and tetracycline. Campylobacter isolates were resistant to ceftriaxone, erythromycin, ciprofloxacin, tetracycline, and nalidixic acid at varying degrees. In fish, Enterococcus isolates showed resistance to penicillin, ampicillin, chloramphenicol, vancomycin, and tetracycline but sensitive to ciprofloxacin, erythromycin, and rifampicin. Isolated strains of Vibrio species showed sensitivity to florfenicol and ciprofloxacin, butresistance to trimethoprim/sulphamethoxazole and erythromycin. Isolates of Aeromonas and Pseudomonas species exhibited resistance to ampicillin and amoxicillin. Specifically, Aeromonashydrophila isolates showed sensitivity to cephradine, doxycycline, erythromycin, and florfenicol. However, resistance was also exhibited against augmentinandtetracycline. The findings constitute public and environmental health threats and suggest the need to promote and advance AMR research in other countries, particularly those on the global hotspot for antimicrobial use.

Keywords: antibiotics, antimicrobial resistance, bacteria, environment, public health

Procedia PDF Downloads 177

Authors: Ismail Mahdi, Nidal Fahsi, Mohamed Hafidi, Abdelmounaim Allaoui, Latefa Biskri

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To meet the worldwide demand for food, smart management of arable lands is needed. This could be achieved through sustainable approaches such as the use of plant growth-promoting microorganisms including bacteria. Phosphate (P) solubilization is one of the major mechanisms of plant growth promotion by associated bacteria. In the present study, we isolated and screened 14 strains from the rhizosphere of Chenopodium quinoa wild grown in the experimental farm of UM6P and assessed their plant growth promoting properties. Next, they were identified by using 16S rRNA and Cpn60 genes sequencing as Bacillus, Pseudomonas and Enterobacter. These strains showed dispersed capacities to solubilize P (up to 346 mg L−1) following five days of incubation in NBRIP broth. We also assessed their abilities for indole acetic acid (IAA) production (up to 795,3 µg ml−1) and in vitro salt tolerance. Three Bacillus strains QA1, QA2, and S8 tolerated high salt stress induced by NaCl with a maximum tolerable concentration of 8%. Three performant isolates, QA1, S6 and QF11, were further selected for seed germination assay because of their pronounced abilities in terms of P solubilization, IAA production and salt tolerance. The early plant growth potential of tested strains showed that inoculated quinoa seeds displayed greater germination rate and higher seedlings growth under bacterial treatments. The positive effect on seed germination traits strongly suggests that the tested strains are growth promoting, halotolerant and P solubilizing bacteria which could be exploited as biofertilizers.

Keywords: phosphate solubilizing bacteria, IAA, Seed germination, salt tolerance, quinoa

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Authors: N. Tabatadze

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The research aim is to study the physical and mechanical characteristics of hydraulic concrete in the surface active environment. The specific goal is to obtain high strength and low deformable concrete based on nano additives, resistant to the aggressive environment. As result of research, the alkali-silica reaction was improved (relative elongation 0,122 % of admixture instead of 0,126 % of basic concrete after 14 days). The aggressive environment impact on the strength of heavy concrete, fabricated on the basis of the hydraulic admixture with the penetrating waterproof additives also was improved (strength on compression R28=47,5 mPa of admixture instead of R28=35,8 mPa). Moreover, water absorption (W=0,59 % of admixture instead of W=1,41 %), water tightness (R14=37,9 mPa instead R14=28,7 mPa) and water-resistance (B=18 instead B=12). The basic parameters of concrete with admixture was improved in comparison with basic concrete.

Keywords: hydraulic concrete, alkali-silica reaction, water absorption, water-resistance

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Authors: Latifat Afolake Ogunfolabo, Hakeem Babafemi Ogunfolabo

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The gastrointestinal tract is densely populated with micro-organism which closely and intensively interacts with the host and ingested feed. Food borne infections are some of the major international challenges that lead to high mortality and also, antimicrobial resistance, which has been classified as a serious threat by World Health Organization. Samples of slaughtered cattle and goats intestines were collected and standard culture methods were used for bacteria isolation and identification. Minimum inhibitory concentration of commonly used antibiotic using modification of the disk diffusion method was carried out on isolates. The samples cultured were all positive to Pseudomonas aeruginosa (95% and 90%), Escherichia coli (85%), Salmonella typhi (70% and 60%), Staphylococcus aureus (75%and 100%), Micrococcus luteus (55% and35%), Bacillus macerans (60% and 5%), Bacillus cereus (25% and 20%), Clostridium perfringens (20% and 5%), Micrococcus varians (20% and 5%), Bacillus subtilis (25% and 5%), Streptococcus faecalis (40% and 25%) and Streptococcus faecium (15% and 10%) in goat and cattle respectively. Also, Proteus mirabilis (40%), Micrococcus luteus (35%), Proteus vulgaris (30%), Klebsiella aerogenes(15%) were isolated from cattle. The total coliform (13.55 x10⁵cfu/gm ± 1.77) and (20.30 x10⁵cfu/gm ± 1.27) counts were significantly higher than the total bacteria count (8.3 x10⁵cfu/gm ± 1.41) and (16.60 x10⁵cfu/gm ±0.49) for goat and cattle respectively. Selected Bacteria count of isolates showed that Staphylococcus aureus had the highest significant value (6.9 x10⁵cfu/gm ± 0.57) and (16.80 x10⁵cfu/gm ± 0.57) Escherichia coli (4.60 x10⁵cfu/gm ± 0.42) and (7.05 x10⁵cfu/gm ± 0.64) while the lowest significant value was obtained in Salmonella/Shigella (1.7 x10⁵cfu/gm ± 0.00) and (1.5 x10⁵cfu/gm ± 0.00) for goat and cattle respectively. Susceptibility of bacteria isolated from slaughtered goat and cattle intestine to commonly used antibiotics showed that the highest statistical significant value for zone of inhibition for goat was obtained for Ciprofloxacin (30.00 ± 2.25, 23.75 ± 2.49, 17.17 ± 1.40) followed by Augmentin (28.33 ± 1.22, 21. 83 ± 2.44, 16.67 ± 1.49), Erythromycin (27.75 ±1.48, 20.25 ± 1.29, 16.67 ± 1.26) while the lowest values were obtained for Ofloxacin (27.17 ± 1.89, 21.42 ± 2.19, 16.83 ± 1.26) respectively and values obtained for cattle are Ciprofloxacin (30.64 ± 1.6, 25.79 ± 1.76, 8.07 ± 11.49) followed by Augmentin (28.29 ± 1.33, 22.64 ± 1.82, 17.43 ± 1.55) Ofloxacin (26.57 ± 2.02, 20.79 ± 2.75, 16.21 ± 1.19) while the lowest values were obtained for Erythromycin (26.64 ± 1.49, 20.29 ± 1.49, 16.29 ± 1.33) at different dilution factor (10⁻¹, 10⁻², 10⁻³) respectively. The isolates from goat and cattle were all susceptible to Augmentin at the three different dilution factors. Some goat isolates are intermediate to Ciprofloxacin and Erythromycin at 10⁻² and 10⁻³, while resistance to Ciprofloxacin at 10⁻³ dilution factor. Ciprofloxacin and Ofloxacin at the dilution factors of 10⁻³ and 10⁻¹ for some cattle isolate and resistance were observed for Ofloxacin and Erythromycin at dilution of 10⁻³. These results indicate the susceptibilities and the antimicrobial resistance to commonly used antibiotic.

Keywords: antibiotic susceptibility, bacteria, cattle, goat, identification

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Authors: Ayuko Itsuki, Sachiyo Aburatani

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Soil neutral sugar contents in Kasuga-yama Hill Primeval Forest, which is a World Heritage Site in Nara, Japan consisting of lowland laurel-leaved forest where natural conditions have been preserved for more than 1,000 years, were examined using the two-step hydrolysis to clarify the source of the neutral sugar and relations with the neutral sugar constituted the soil organic matter and the microbial biomass. Samples were selected from the soil (L, F, H and A horizons) surrounding laurel-leaved (BB-1) and Carpinus japonica (BB-2 and PW) trees for analysis. The neutral sugars were one factor of increasing the fungal and bacterial biomass in the laurel-leaved forest soil (BB-1). The more neutral sugar contents in the Cryptomeria japonica forest soil (PW) contributed to the growth of the bacteria and fungi than those of in the Cryptomeria japonica forest soil (BB-2). The neutral sugars had higher correlation with the numbers of bacteria and fungi counted by the dilution plate count method than by the direct microscopic count method. The numbers of fungi had higher correlation with those of bacteria by the dilution plate method.

Keywords: forest soil, neutral sugars, soil organic matter, two-step hydrolysis

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Authors: Bisi-Johnson, Mary A., Hamzart A. Oyelade, Kehinde A. Adediran, Saheed A. Akinola

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Geophagic and cosmetic clays are among potential nano-material which occur naturally and are of various forms. The use of these nano-clays is a common practice in both rural and urban areas mostly due to tradition and medicinal reasons. These naturally occurring materials can be valuable sources of nano-material by serving as nano-composites. The need to ascertain the safety of these materials is the motivation for this research. Physical Characterization based on the hue value and microbiological qualities of the nano-clays were carried out. The Microbial analysis of the clay samples showed considerable contamination with both bacteria and fungi with fungal contaminants taking the lead. This observation may not be unlikely due to the ability of fungi species to survive harsher growth conditions than bacteria. 'Atike pupa' showed no bacterial growth. The clay with the largest bacterial count was Calabash chalk (Igbanke), while that with the highest fungal count was 'Eko grey'. The most commonly isolated bacteria in this study were Clostridium spp. and Corynebacterium spp. while fungi included Aspergillus spp. These results are an indication of the need to subject these clay materials to treatments such as heating before consumption or topical usage thereby ascertaining their safety.

Keywords: nano-material, clay, microorganism, quality

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Authors: Supawadee Phetkhajone, Wisuwat Songnuan

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Metalaxyl is one of the most common and effective fungicides used to control Phytophthora palmivora infection in durian (Durio zibethinus L.). The efficacy of metalaxyl residue in durian under greenhouse condition was evaluated using bioassay. Durian seedlings were treated with 2 methods of application, spraying, and soil drenching of metalaxyl, at recommended concentration (1000 mg/L). Mock treated samples were treated with 0.1% Tween20 and water for spraying and soil drenching methods, respectively. The experiment was performed in triplicates. Leaves were detached from treated plants at 0, 1, 7, 15, 20, 30, and 60 days after application, inoculated with metalaxyl-resistant and metalaxyl-sensitive isolates of P. palmivora, and incubated in a high humidity chamber for 5 days at room temperature. Metalaxyl efficacy was determined by measuring the lesion size on metalaxyl treated and mock treated samples. The results showed that metalaxyl can control metalaxyl-sensitive isolate of P. palmivora for at least 30 days after application in both methods of application. The metalaxyl-resistant isolate was not inhibited in all treatments. Leaf samples from spraying method showed larger lesions compared to soil drench method. These results demonstrated that metalaxyl applications, especially soil drenching methods showed high efficacy to control metalaxyl-sensitive isolates of P. palmivora, although it cannot control metalaxyl-resistant isolates of P. palmivora in all treatments. These qualitative data indicate that metalaxyl may suitable to control metalaxyl-sensitive isolates of P. palmivora infection.

Keywords: bioassay, degradation, durian, metalaxyl

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Authors: Alisha Akya, Afsaneh salami

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Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen associated with nosocomial infections. One of the major concerns for the treatment of P. aeruginosa infections is its resistant to a variety of antibiotics. The purpose of this study was to assess the dissemination of p. aeruginosa isolates obtained from major hospitals in Kermanshah, west of Iran. Materials and Methods: Antibiotic susceptibility testing was performed using the minimal inhibitory concentrations. Mettalo-beta-lactamase was investigated using the double disk diffusion (DDST) test and PCR. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE). Results: The 60 P. aeruginosa isolates, 30 (50%) were resistant to gentamicin, 38 (63/3%) to piperacilin, 42 (70%) to ceftazidime, and 45 (75%) to cefepime. Twenty-nine (48/3%) isolates were MBLs producer based on the DDST test. Five (8/3%) isolates were positive for VIM gene and 4 of them were from burn specimens. PFGE analysis among MBLs producers revealed 12 distinct genotype patterns. A pattern covering the highest number of strains was determined as the dominant clone. Conclusions: Our study showed that P. aeruginosa strains can be spread between patients in hospitals or acquired from different environmental sources. P. aeruginosa isolates were highly resistant to antibiotics and, therefore, the susceptibility of isolates to antibiotics should be tested before treatment. Given the clinical significance of MBLs producing isolates, identification of these organisms is essential in the hospitals in order to get a better therapeutic response and control of bacterial dissemination.

Keywords: clonal dissemination, mettalo-beta-lactamase, Pseudomonas aeruginosa, PFGE

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Authors: Thangaraj Arasakumar, Athar Ata, Palathurai Subramaniam Mohan

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A series of novel 4-quinolone-3-carboxylic acid grafted spiropyrrolidines as new type of antibacterial agents were synthesized via multicomponent 1,3-dipolar cycloaddition reaction of an azomethine ylides with a newly prepared (E)-4-oxo-6-(3-phenyl-acryloyl)-1,4-dihydro-quinoline-3-carboxylic acids in high regioselectivity with good yields. The structure of cycloadduct characterized by FT IR, mass, 1H, 13C, 2D NMR techniques and elemental analysis. Structure and spectrometry of compound 8a has been investigated theoretically by using HF and DFT approach at B3LYP, M05-2x/6-31G* levels of theories. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. A good agreement is found between the measured and calculated values. The DFT studies support the molecular mechanism of this cycloaddition reaction and determine the molecular electrostatic potential and thermodynamic properties. Furthermore, the antibacterial activities of synthesized compounds were evaluated against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria strains (Escherichia coli, Klebsiella pneumoniae). Among 21 compounds screened, 8f and 8p were found to be more active against tested bacteria.

Keywords: antibacterial activity, azomethine ylide, DFT calculation, spirooxindole

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Authors: Waad Al Saleemi, Badriya Al Adawi, Zaaima Al Jabri, Sahim Al Ghafri, Jalila Al Hadhramia

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Objectives: Using standard lab methods, a positive blood culture requires a minimum of two days (two occasions of overnight incubation) to obtain a final identification (ID) and antimicrobial susceptibility results (AST) report. In this study, we aimed to evaluate the accuracy and precision of identification and antimicrobial susceptibility testing of an alternative method (direct method) that will reduce the turnaround time by 24 hours. This method involves the direct inoculation of positive blood culture broths into the Phoenix system using serum separation tubes (SST). Method: This prospective study included monomicrobial-positive blood cultures obtained from January 2022 to May 2023 in SQUH. Blood cultures containing a mixture of organisms, fungi, or anaerobic organisms were excluded from this study. The result of the new “direct method” under study was compared with the current “standard method” used in the lab. The accuracy and precision were evaluated for the ID and AST using Clinical and Laboratory Standards Institute (CLSI) recommendations. The categorical agreement, essential agreement, and the rates of very major errors (VME), major errors (ME), and minor errors (MIE) for both gram-negative and gram-positive bacteria were calculated. Passing criteria were set according to CLSI. Result: The results of ID and AST were available for a total of 158 isolates. Of 77 isolates of gram-negative bacteria, 71 (92%) were correctly identified at the species level. Of 70 isolates of gram-positive bacteria, 47(67%) isolates were correctly identified. For gram-negative bacteria, the essential agreement of the direct method was ≥92% when compared to the standard method, while the categorical agreement was ≥91% for all tested antibiotics. The precision of ID and AST were noted to be 100% for all tested isolates. For gram-positive bacteria, the essential agreement was >93%, while the categorical agreement was >92% for all tested antibiotics except moxifloxacin. Many antibiotics were noted to have an unacceptable higher rate of very major errors including penicillin, cotrimoxazole, clindamycin, ciprofloxacin, and moxifloxacin. However, no error was observed in the results of vancomycin, linezolid, and daptomycin. Conclusion: The direct method of ID and AST for positive blood cultures using SST is reliable for gram negative bacteria. It will significantly decrease the turnaround time and will facilitate antimicrobial stewardship.

Keywords: bloodstream infection, oman, direct ast, blood culture, rapid identification, antimicrobial susceptibility, phoenix, direct inoculation

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Authors: Suman Chaudhary, Rinku Dhanker, Tanvi, Sneh Goyal

Abstract:

Sulphur oxidizing bacteria (SOB) have marked their significant role in perspectives of maintaining healthy environment as researchers from all over the world tested and apply these in waste water treatment plants, bioleaching of heavy metals, deterioration of bridge structures, concrete and for bioremediation purposes, etc. Also, these SOB are well adapted in all kinds of environment ranging from normal soil, water habitats to extreme natural sources like geothermal areas, volcanic eruptions, black shale and acid rock drainage (ARD). SOB have been isolated from low pH environment of anthropogenic origin like acid mine drainage (AMD) and bioleaching heaps, hence these can work efficiently in different environmental conditions. Besides having many applications in field of environment science, they may be proven to be very beneficial in area of agriculture as sulphur is the fourth major macronutrients required for the growth of plants. More amount of sulphur is needed by pulses and oilseed crops with respect to the cereal grains. Due to continuous use of land for overproduction of more demanding sulphur utilizing crops and without application of sulphur fertilizers, its concentration is decreasing day by day, and thus, sulphur deficiency is becoming a great problem as it affects the crop productivity and quality. Sulphur is generally found in soils in many forms which are unavailable for plants (cannot be use by plants) like elemental sulphur, thiosulphate which can be taken up by bacteria and converted into simpler forms usable by plants by undergoing a series of transformations. So, keeping the importance of sulphur in view for various soil types, oilseed crops and role of microorganisms in making them available to plants, we made an effort to isolate, optimize, and characterize SOB. Three potential strains of bacteria were isolated, namely SSF7, SSA21, and SSS6, showing sulphate production of concentration, i.e. 2.268, 3.102, and 2.785 mM, respectively. Also, these were optimized for various culture conditions like carbon, nitrogen source, pH, temperature, and incubation time, and characterization was also done.

Keywords: sulphur oxidizing bacteria, isolation, optimization, characterization, sulphate production

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Authors: Sameh Abu El-Soud, Zahra Zayed, Safwan Khedr, Adel M. Belal

Abstract:

The population increase in Egypt is urging for horizontal land development which became a demand to allow the benefit of different natural resources and expand from the narrow Nile valley. However, this development is facing challenges preventing land development and agriculture development. Desertification and moving sand dunes in the west sector of Egypt are considered the major obstacle that is blocking the ideal land use and development. In the proposed research, the sandy soil is treated biologically using Bacillus pasteurii bacteria as these bacteria have the ability to bond the sand partials to change its state of loose sand to cemented sand, which reduces the moving ability of the sand dunes. The procedure of implementing the Microbial Induced Carbonate Precipitation Technique (MICP) technique is examined, and the different factors affecting on this process such as the medium of bacteria sample preparation, the optical density (OD600), the reactant concentration, injection rates and intervals are highlighted. Based on the findings of the MICP treatment for sandy soil, conclusions and future recommendations are reached.

Keywords: soil stabilization, biological treatment, microbial induced carbonate precipitation (MICP), sand cementation

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Authors: Navneetinder Singh, Harprabhjot Singh, Harpreet Singh, Supreet Singh

Abstract:

Many materials are known to mankind that is widely used for synthesis of corrosion resistant hydrophobic coatings. In the current work, novel hydrophobic composite was synthesized by mixing polytetrafluoroethylene (PTFE) and 20 weight% ceria particles followed by sintering. This composite had same hydrophobic behavior as PTFE. Moreover, composite showed better scratch resistance than virgin PTFE. Pits of plasma sprayed Ni₃Al coating were exploited to hold PTFE composite on the substrate as Superni-75 alloy surface through sintering process. Plasma sprayed surface showed good adhesion with the composite coating during scratch test. Potentiodynamic corrosion test showed 100 fold decreases in corrosion rate of coated sample this may be attributed to inert and hydrophobic nature of PTFE and ceria.

Keywords: polytetrafluoroethylene, PTFE, ceria, coating, corrosion

Procedia PDF Downloads 357

Authors: Mohammad Reza Haj Seyed Hadi, Fereshteh Ghanepasand, Mohammad Taghi Darzi

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The main objective of this study was to determine the effects of Nitrogen fixing bacteria and manure application on the seed yield and yield components in black cumin (Nigella sativa L.). The experiment was carried out at the RAN Research Station in Firouzkouh in 2012. A 4×4 factorial experiment, arranged in a randomized complete blocks designed with three replications. The treatments consisted of 4 level of nitrogen fixing bacteria (control, Azotobacter, Azospirillum and Azotobacter + Azospirillum) and 4 level of manure (0, 2.5, 5 and 7.5 ton ha-1). The present results have shown that the highest height, 1000 seeds weight, seed number per follicle, follicle yield, seed yield and harvest index were obtained after using Azotobacter and Azospirillum, simultaneously. Manure application only affects on follicle yield and by 5ton manure ha-1 the highest follicle yield obtained. Results of this investigation showed that the maximum seed yield obtained when Aotobacter+Azospirillum inoculated with black cumin seeds and 5 ton manure ha-1 applied. Combined application of nitrogen fixing bacteria and manure can be helpful in developing of production and yield in Black cumin.

Keywords: azotobacter, azospirillum, black cumin, yield, yield components

Procedia PDF Downloads 446

Authors: Sanam Pudasaini, A. T. K. Perera, Ahmed Syed Shaheer Uddin, Sum Huan Ng, Chun Yang

Abstract:

Development of high-efficiency and environment friendly bacterial inactivation methods is of great importance for preventing waterborne diseases which are one of the leading causes of death in the world. Traditional bacterial inactivation methods (e.g., ultraviolet radiation and chlorination) have several limitations such as longer treatment time, formation of toxic byproducts, bacterial regrowth, etc. Recently, an electroporation-based inactivation method was introduced as a substitute. Here, an electroporation-based continuous flow microfluidic device equipped with an array of micropillars is developed, and the device achieved high bacterial inactivation performance ( > 99.9%) within a short exposure time ( < 1 s). More than 99.9% reduction of Escherichia coli bacteria was obtained for the flow rate of 1 mL/hr, and no regrowth of bacteria was observed. Images from scanning electron microscope confirmed the formation of electroporation-induced nano-pore within the cell membrane. Through numerical simulation, it has been shown that sufficiently large electric field strength (3 kV/cm), required for bacterial electroporation, were generated using PDMS micropillars for an applied voltage of 300 V. Further, in this method of inactivation, there is no involvement of chemicals and the formation of harmful by-products is also minimum.

Keywords: electroporation, high-efficiency, inactivation, microfluidics, micropillar

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Authors: Irina E. Sukovataya, Oleg S. Sutormin, Valentina A. Kratasyuk

Abstract:

Effect of viscosity of media on kinetic parameters of the coupled enzyme system NADH:FMN-oxidoreductase–luciferase was investigated with addition of organic solvents (glycerol and sucrose), because bioluminescent enzyme systems based on bacterial luciferases offer a unique and general tool for analysis of the many analytes and enzymes in the environment, research, and clinical laboratories and other fields. The possibility of stabilization and increase of activity of the coupled enzyme system NADH:FMN-oxidoreductase–luciferase activity in vicious aqueous-organic mixtures have been shown.

Keywords: coupled enzyme system of bioluminescence bacteria NAD(P)H:FMN-oxidoreductase–luciferase, glycerol, stabilization of enzymes, sucrose

Procedia PDF Downloads 375

Authors: Anuj Tyagi, Balwinder Singh, Naveen Kumar B. T., Niraj K. Singh

Abstract:

Characterization of diverse microbial communities in specific environment plays a crucial role in the better understanding of their functional relationship with the ecosystem. It is now well established that gut microbiome of fish is not the simple replication of microbiota of surrounding local habitat, and extensive species, dietary, physiological and metabolic variations in fishes may have a significant impact on its composition. Moreover, overuse of antibiotics in human, veterinary and aquaculture medicine has led to rapid emergence and propagation of antibiotic resistance genes (ARGs) in the aquatic environment. Microbial communities harboring specific ARGs not only get a preferential edge during selective antibiotic exposure but also possess the significant risk of ARGs transfer to other non-resistance bacteria within the confined environments. This phenomenon may lead to the emergence of habitat-specific microbial resistomes and subsequent emergence of virulent antibiotic-resistant pathogens with severe fish and consumer health consequences. In this study, gut microbiota of freshwater carp (Labeo rohita) was investigated by shotgun metagenomics to understand its taxonomic composition and functional capabilities. Metagenomic DNA, extracted from the fish gut, was subjected to sequencing on Illumina NextSeq to generate paired-end (PE) 2 x 150 bp sequencing reads. After the QC of raw sequencing data by Trimmomatic, taxonomic analysis by Kraken2 taxonomic sequence classification system revealed the presence of 36 phyla, 326 families and 985 genera in the fish gut microbiome. At phylum level, Proteobacteria accounted for more than three-fourths of total bacterial populations followed by Actinobacteria (14%) and Cyanobacteria (3%). Commonly used probiotic bacteria (Bacillus, Lactobacillus, Streptococcus, and Lactococcus) were found to be very less prevalent in fish gut. After sequencing data assembly by MEGAHIT v1.1.2 assembler and PROKKA automated analysis pipeline, pathway analysis revealed the presence of 1,608 Metacyc pathways in the fish gut microbiome. Biosynthesis pathways were found to be the most dominant (51%) followed by degradation (39%), energy-metabolism (4%) and fermentation (2%). Almost one-third (33%) of biosynthesis pathways were involved in the synthesis of secondary metabolites. Metabolic pathways for the biosynthesis of 35 antibiotic types were also present, and these accounted for 5% of overall metabolic pathways in the fish gut microbiome. Fifty-one different types of antibiotic resistance genes (ARGs) belonging to 15 antimicrobial resistance (AMR) gene families and conferring resistance against 24 antibiotic types were detected in fish gut. More than 90% ARGs in fish gut microbiome were against beta-lactams (penicillins, cephalosporins, penems, and monobactams). Resistance against tetracycline, macrolides, fluoroquinolones, and phenicols ranged from 0.7% to 1.3%. Some of the ARGs for multi-drug resistance were also found to be located on sequences of plasmid origin. The presence of pathogenic bacteria and ARGs on plasmid sequences suggested the potential risk due to horizontal gene transfer in the confined gut environment.

Keywords: antibiotic resistance, fish gut, metabolic pathways, microbial diversity

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Authors: Muhammad Raqib Rasul, Tavga Sulaiman Rashid

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Fertilization increases efficiency and obtains better quality of product recovery in agricultural activities. However, fertilizer consumption increased exponentially throughout the world, causing severe environmental problems. Biofertilizers can be a practical approach to minimize chemical fertilizer sources and ultimately develop soil fertility. This study was carried out to isolate, identify and characterize bacteria from medicinal plant (Rumex tuberosus L. and Verbascum sp.) rhizosphere for in vivo screening. 25 bacterial isolates were isolated and several biochemical tests were performed. Two isolates that were positive for most biochemical tests were chosen for the field experiment. The isolates were identified as Go1 Alcaligenes faecalis (Accession No. OP001725) and T11 (Bacillus sp.) based on the 16S rRNA sequence analysis that was compared with related bacteria in GenBank database using MEGA 6.1. For the field trial isolate GO1 and T11 (separately and mixed), NPK as a positive control was used. Both isolates increased plant height, chlorophyll content, number of tubers, and tuber’s weight. The results demonstrated that these two isolates of bacteria can potentially replace with chemical fertilizers for potato production.

Keywords: biofertilizer, Bacillus subtilis, Alcaligenes faecalis, potato tubers, in vivo screening

Procedia PDF Downloads 92

Authors: John Hang Leung, Shyh-Yau Wang, Hei-Tung Yip, Fion, Ho Tsung-chin, Agnes LF Chan

Abstract:

Objectives: Platinum-resistant ovarian cancer has a short overall survival of 9–12 months and limited treatment options. The combination of immunotherapy and targeted therapy appears to be a promising treatment option for patients with ovarian cancer, particularly to patients with platinum-resistant recurrent ovarian cancer (PRrOC). However, there are no direct head-to-head clinical trials comparing their efficacy and toxicity. We, therefore, used a network to directly and indirectly compare seven newer immunotherapies or targeted therapies combined with chemotherapy in platinum-resistant relapsed ovarian cancer, including antibody-drug conjugates, PD-1 (Programmed death-1) and PD-L1 (Programmed death-ligand 1), PARP (Poly ADP-ribose polymerase) inhibitors, TKIs (Tyrosine kinase inhibitors), and antiangiogenic agents. Methods: We searched PubMed (Public/Publisher MEDLINE), EMBASE (Excerpta Medica Database), and the Cochrane Library electronic databases for phase II and III trials involving PRrOC patients treated with immunotherapy or targeted therapy plus chemotherapy. The quality of included trials was assessed using the GRADE method. The primary outcomes compared were progression-free survival, the secondary outcomes were overall survival and safety. Results: Seven randomized controlled trials involving a total of 2058 PRrOC patients were included in this analysis. Bevacizumab plus chemotherapy showed statistically significant differences in PFS (Progression-free survival) but not OS (Overall survival) for all interested targets and immunotherapy regimens; however, according to the heatmap analysis, bevacizumab plus chemotherapy had a statistically significant risk of ≥grade 3 SAEs (Severe adverse effects), particularly hematological severe adverse events (neutropenia, anemia, leukopenia, and thrombocytopenia). Conclusions: Bevacizumab plus chemotherapy resulted in better PFS as compared with all interested regimens for the treatment of PRrOC. However, statistical differences in SAEs as bevacizumab plus chemotherapy is associated with a greater risk for hematological SAE.

Keywords: platinum-resistant recurrent ovarian cancer, network meta-analysis, immune checkpoint inhibitors, target therapy, antiangiogenic agents

Procedia PDF Downloads 61

Authors: B. D. Ravindra, A. K. Tyagi, C. Kathirvelan

Abstract:

Some micronutrients in food (milk and meat), called ‘functional food components’ exert beneficial effects other than their routine nutrient function and conjugated linoleic acid (CLA) is an unsaturated fatty acid of ruminant origin, an example of this category. However, recently the fear of hypercholesterolemia due to saturated fats has led to the avoidance of dietary fat especially of animal origin despite its advantages such as lowering blood cholesterol, immuno-modulation and anticarcinogenic property due to the presence of CLA. The dietary increase of linoleic acid (LA) and linolenic acid (LNA) is one of the feeding strategies for increasing the CLA concentration in milk. Butyrivibrio fibrisolvens is the one potential rumen bacteria, which has high potential to isomerize LA to CLA. The study was conducted to screen the different oils for CLA production, selected based on their LA concentration. Butyrivibrio fibrisolvens culture (strain 49, MZ3, 30/10) were isolated from the rumen liquor of fistulated Buffalo (age ≈ 3 years; weight ≈ 250 kg) were used in in-vitro experiments, further work was carried out with three oils viz., sunflower, mustard and soybean oil at different concentration (0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 g/L of media) to study the growth of bacteria and CLA production at different incubation period (0, 8, 12, 18, 24, 48, 72 h). In the present study, growth of the bacteria was decreased linearly with increase in concentration of three oils. However, highest decrease in growth was recorded at the concentration of 0.30 g of three oils per litre of the media. Highest CLA production was 51.96, 42.08 and 25.60 µg/ml at 0.25 g and it decreased to 48.19, 39.35 and 23.41 µg/ml at 0.3 g supplementation of sunflower, soybean, and mustard oil per litre of the media, respectively at 18 h incubation period. The present study indicates the Butyrivibrio fibrisolvens bacteria involves in the biohydrogenation process, and LA rich sunflower meal can be used to improve the CLA production in rumen and thereby increasing the CLA concentration of milk.

Keywords: Butyrivibrio fibrisolvens, CLA, fatty acids, sunflower oil

Procedia PDF Downloads 359

Authors: Emil Iskandarov, Nazrin Agayeva

Abstract:

Background: The effectiveness of hormone suppressive therapy (HST) in patients with nodular goiter (NG) is controversial. The aim of this study was to identify the impact of long-time HST on the Quality of Life (QoL) of patients with NG. Material and Methods: A retrospective analysis of 146 patients with NG showed treated with HST showed that in 38,4% of cases, HST was not effective. Nodules were increased in size and moreover, and new nodules were developed. Statistical procedure identified the predictors of resistant nodules: only one nodule in the left lobe; nodule size >17mm; calcinate within the nodule. 174 patients with NG, by whom predictors of resistant nodules were established, were informed about the results of previous research and surgery was suggested. Eighty-eight patients (the basic group) agreed with surgery and thyroidectomy was led. 86 patients (control group) ignored the suggestion and wished to receive HST. 3, 6 and 12 months after starting HST; control group patients were examined. HST was non-effective and patients, due to developing symptoms, were operated on. Patients in both groups were followed up 3, 6 and 12 months after thyroidectomy. Quality of Life was checked with the SF-36 survey form and compared between groups. The statistical analysis was performed with the non-parametric Mann–Whitney U test and with the Student t-test. P values ＜0.05 were considered statistically significant. Results and Discussions: QoL of patients in the basic and control groups 3 months after surgery was almost the same. However, Emotional problems severely interfered with patients in a control group with normal social activities with family, friends, and neighbors. The causes were related to the non-effective HST treatment before surgery: stress for forgetting to take drugs timely every day for a long time; blood tests for thyroid hormone level; needle biopsies of nodules for cancer screening and regular ultrasound investigations, which showed that nodules not diminished in size. Changing the treatment method after 1-year non-effective HST and delayed surgery negatively impacted patient's QoL. Social role functioning and mental health in the control group were also impaired and the difference between the results in the basic group was statistically significant (p <0.05). Conclusion: Predictors, such as only one nodule, the width of nodules more than 17mm, and the existence of calcinate within the nodule, are able to forecast the resistant nodules. HST in patients with resistant nodules is non-effective and surgery is suggested in patients with resistant nodules in the thyroid gland. Long time HST has a negative impact on the QoL patient after surgery.

Keywords: thyroid gland, nodule, hormone suppressive therapy, quality of life

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