Search results for: strains

Authors: Fatima Bouazza, Rachida Hassikou, Lamiae Amallah, Jihane Ennadir, Khadija Khedid

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This study evaluated the in vitro resistance and susceptibility of Enterobacteriaceae (Escherichia coli and Klebsiella oxytoca strains) and Staphylococci strains, isolated from sheep’s milk, against antibiotics and essential oils from Thymus satureioides and Mentha pulegium. Antibiotic resistance tests were done using disc diffusion while essential oils were extracted by steam distillation, and yields were calculated relative to plant dry matter. Gas chromatography-mass Spectrometry (GC-MS) was used to analyze each oil's chemical composition. The AMC, CTX, FOX, NA, CN, CIP, and OFX were very effective against the E. coli strains tested. Half of the strains were resistant to AMC, 60% to TIC, and 80% to TE. The K. oxytoca was resistant against AMC, FOX, and TIC (100%). Antibiotic-resistant testing on Staphylococci strains indicated Staphylococcus capitis and Staphylococcus chromogenes as the most sensitive. Staphylococcus aureus, Staphylococcus xylosus, and Staphylococcus cohnii ureal exhibited less resistance to OX, TE, PT, E, and P. The M. pulegium resulted in a higher yield of essential oil of 3.2% oil compared to T. satureioides with only 1.85% yield. Staphylococcus aureus, Staphylococcus xylosus, and Staphylococcus cohnii ureal had lower OX, TE, PT, E, and P resistance. M. pulegium yielded 3.2% essential oil compared to 1.85% for T. satureioides. The monoterpene oxygenated derivatives, monoterpene hydrocarbons, and phenols are found in essential oil extracts. T. satureioides essential oil had high antibacterial activity even at low concentrations (0.2; 0.55 g/mL). The Minimal Bactericidal Concentration (MBC) values indicate that the essential oils from the plants analyzed had bactericidal effects on all strains tested and are similar to the Minimal Inhibitory Concentration (MIC) values. The high antibacterial properties of these medicinal plants, against bacteria isolated from sheep’s milk, provide an opportunity to use these medicinal plants in the breeding sector as additives and preservatives in the dairy industry.

Keywords: antibiotic resistance, medicinal plants, essential oils, enterobacteriaceae, staphylococci, sheep milk

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Authors: Abdelkarim Mahdhi, Fdhila Kais, Faouzi Lamari, Zeineb Hmila, Fathi Kamoun, Maria Ángeles Esteban, Amina Bakhrouf

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Pathogenic bacteria are considered to be responsible for several infectious diseases in aquaculture. To overcome diseases in fish culture, the use of antimicrobial drugs as strategy, have been adopted. The use of probiotic was a promising approach to avoid the risk associated to pathogenic bacteria. To find a biological control treatment against pathogens, we undertook this investigation to study the maintain of the probiotic properties of Bacillus sp., such as viability, adhesive ability to abiotic surface, antibacterial activity and pathogenicity/toxicity, under marine starvation conditions. Our data revealed that the tested strains maintained their capacity to inhibit pathogens in vivo and in vitro conditions. These strains maintain their adhesive capacity to polystyrene and do not demonstrate the pathogenic or toxic effect to the host. The obtained results give insight about the effect of starvation conditions on the physiological responses of these Bacillus strains that can be considered as a potential candidate’s probiotic.

Keywords: bacillus, probiotic, cell viability, starvation conditions

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Authors: M. Suwaibah, S. W. Tan, I. Aiini, K. Yusoff, A. R. Omar

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Respiratory diseases are the most important infectious diseases affecting poultry worldwide. One of the avian respiratory virus of global importance causing significant economic losses is Infectious Bronchitis Virus (IBV). The virus causes a wide spectrum disease known as Infectious Bronchitis (IB), affecting not only the respiratory system but also the kidney and the reproductive system, depending on its strain. IB and Newcastle disease are two of the most prevalent diseases affecting poultry in Malaysia. However, a study on the molecular characterization of Malaysian IBV is lacking. In this study, an IBV strain IBS130 which was isolated in 2015 was fully sequenced using next-gene sequencing approach. Sequence analysis of IBS130 based on the complete genome, polyprotein 1ab and S1 genes were compared with other IBV sequences available in Genbank, National Center for Biotechnology Information (NCBI). IBV strain IBS130 is characterised as QX-like strain based on whole genome and S1 gene sequence analysis. Comparisons of the virus with other IBV strains showed that the nucleotide identity ranged from 67% to 99.2%, depending on the region analysed. The similarity in whole genome nucleotide ranging from 84.9% to 90.7% with the least similar was from Singapore strains (84.9%) and highly similar with China QX-like strains. Meanwhile, the similarity in polyprotein 1ab ranging from 85.3% to 89.9% with the least similar to Singapore strains (85.3%) and highly similar with Mass strains from USA.

Keywords: infectious bronchitis virus, phylogenetic analysis, chicken, Malaysia

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Authors: J. Singh, Swati Dubey, R. P. Singh

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Microalgal strains can accumulate greatly enhanced levels of lipids under nitrogen-deficient condition, making these as one of the most promising sustainable sources for biofuel production. High-grade biofuel production from microalgal biomass could be facilitated by analysing the lipid content of the microalgae and enumerating its dynamics under varying nutrient conditions. In the present study, a detailed investigation of changes in lipid composition in Chlorella species and Scenedesmus abundans in response to nitrogen limited condition was performed to provide novel mechanistic insights into the lipidome during stress conditions. The mass spectroscopic approaches mainly LC-MS and GC-MS were employed for lipidomic profiling in both the microalgal strains. The analyses of lipid profiling using LC-MS revealed distinct forms of lipids mainly phospho- and glycolipids, including betaine lipids, and various other forms of lipids in both the microalgal strains. As detected, an overall decrease in polar lipids was observed. However, GC-MS analyses had revealed that the synthesis of the storage lipid i.e. triacylglycerol (TAG) was substantially stimulated in both the strains under nitrogen limited conditions. The changes observed in the overall fatty acid profile were primarily due to the decrease in proportion of polar lipids to TAGs. This study had enabled in analysing a detailed and orchestrated form of lipidomes in two different microalgal strains having potential for biodiesel production.

Keywords: biofuel, GC-MS, LC-MS, lipid, microalgae

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Authors: Sabeen Alam, Mehboob Alam

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The research work entitled “Effect of Bacillus pumilus strains on heavy metal accumulation in lettuce grown on contaminated soil” focused on functional role of Bacillus pumilus strains inoculated with lettuce seed in mitigating heavy metal in chromite mining soil. In this experiment, factor A was three Bacillus pumilus strains (sequence C-2PMW-8, C-1 SSK-8 and C-1 PWK-7) while soil used for this experiment was collected from Prang Ghar mining site and lettuce seeds were grown in three levels of chromite mining soil (2.27, 4.65 and 7.14 %). For mining soil minimum days to germinate noted in lettuce grown on garden soil inoculated with sequence. Maximum germination percentage noted was for C-1 SSK-8 grown on garden soil, maximum lettuce height for sequence C-2 PWM-8, fresh leaf weight for C-1 PWK-7 inoculated lettuce, dry weight of lettuce leaf for lettuce inoculated with C-1 SSK-8 and C-1 PWK-7 strains, number of leaves per plant for lettuce inoculated with C-1 SSK-8, leaf area for C-2 PMW-8 inoculated lettuce, survival percentage for C-1 SSK-8 treated lettuce and chlorophyll content for C-2 PMW-8. Results related to heavy metals accumulation showed that minimum chromium was in lettuce and in soil for all three sequences, cadmium (Cd) in lettuce and in soil for all three sequences, manganese (Mn) in lettuce and in soil for three sequences, lead (Pb) in lettuce and in soil for three sequences. It can be concluded that chromite mining soil significantly reduced the growth and survival of lettuce, but when lettuce was inoculated with Bacillus.pumilus strains, it enhances growth and survival. Similarly, minimum heavy metal accumulation in plant and soil, regardless of type of Bacillus pumilus used, all three sequences has same mitigating effect on heavy metal in both soil and lettuce. All the three Bacillus pumilus strains ensured reduction in heavy metals content (Mn, Cd, Cr) in lettuce, below the maximum permissible limits of WHO 2011.

Keywords: bacillus pumilus, heavy metals, permissible limits, lettuce, chromite mining soil, mitigating effect

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Authors: Vinod Kumar Arya

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Creep analysis of a thick-walled composite anisotropic cylinder under internal pressure and considering large strains is presented. Using a threshold creep law for composite materials, expressions for stresses, strains, and strain rates are derived for several anisotropic cases. Numerical results, presented through several graphs and tables, depict the effect of anisotropy on the stress, strain, and strain rate distributions. Since for a specific type of material anisotropy described in the paper, these quantities are found to have the lowest values at the inner radius (the potential location of cylinder failure), it is concluded that by employing such an anisotropic material for the design of a thick-walled cylinder a longer service life for the cylinder may be achieved.

Keywords: creep, composites, large strains, thick-walled cylinders, anisotropy

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Authors: Asma Afshari, Abdollah Jamshidi, Jamshid Razmyar, Mehrnaz Rad

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Clostridium perfringens is a serious pathogen which causes enteric diseases in domestic animals and food poisoning in humans. Spores can survive cooking processes and play an important role in the possible onset of disease. In this study RAPD-PCR and REP-PCR were used to examine the genetic diversity of 49isolates ofC. Perfringens type A from 3 different sources. The results of RAPD-PCR revealed the most genetic diversity among poultry isolates, while human isolates showed the least genetic diversity. Cluster analysis obtained from RAPD_PCR and based on the genetic distances split the 49 strains into five distinct major clusters (A, B, C, D, and E). Cluster A and C were composed of isolates from poultry meat, cluster B was composed of isolates from human feces, cluster D was composed of isolates from minced meat, poultry meat and human feces and cluster E was composed of isolates from minced meat. Further characterization of these strains by using (GTG) 5 fingerprint repetitive sequence-based PCR analysis did not show further differentiation between various types of strains. To our knowledge, this is the first study in which the genetic diversity of C. perfringens isolates from different types of meats and human feces has been investigated.

Keywords: C. perfringens, genetic diversity, RAPD-PCR, REP-PCR

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Authors: M. D. Asemoloye, S. G. Jonathan, A. Rafiq, O. J. Olawuyi, D. O. Adejoye

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Calmodulin is one of the intracellular calcium proteins that regulates large spectrum of enzymes and cellular functions including metabolism of cyclic nucleotides and glycogen. The potentials of calmodulin gene in fungi necessitates their genetic response and their strong cassette of enzyme secretions for pesticide degradation. Therefore, this study was carried out to investigate the ‘Transcriptomic’ response of calmodulin encoding genes in Talaromyces fungi in response to 2, 2-dichlorovinyl dimethyl phosphate (DDVP or Dichlorvos) an organophosphate pesticide and γ-Hexachlorocyclohexane (Lindane) an organochlorine pesticide. Fungi strains isolated from rhizosphere from grasses rhizosphere in pesticide polluted sites were subjected to percentage incidence test. Two most frequent fungi were further characterized using ITS gene amplification (ITS1 and ITS4 combinations), they were thereafter subjected to In-vitro DDVP and lindane tolerance tests at different concentrations. They were also screened for presence and expression of calmodulin gene (caM) using RT-PCR technique. The two Talaromyces strains had the highest incidence of 50-72% in pesticide polluted site, they were both identified as Talaromyces astroroseus asemoG and Talaromyces purpurogenum asemoN submitted in NCBI gene-bank with accession numbers KY488464 and KY488468 respectively. T. astroroseus KY488464 tolerated DDVP (1.23±0.023 cm) and lindane (1.11±0.018 cm) at 25 % concentration while T. purpurogenum KY488468 tolerated DDVP (1.33±0.061 cm) and lindane (1.54±0.077 cm) at this concentration. Calmodulin gene was detected in both strains, but RT-PCR expression of caM gene revealed at 900-1000 bp showed an under-expression of caM in T. astrorosues KY488464 but overexpressed in T. purpurogenum KY488464. Thus, the calmodulin gene response of these fungal strains to both pesticides could be considered in monitoring the potentials of fungal strains to pesticide tolerance and bioremediation of pesticide in polluted soil.

Keywords: Calmodulin gene, pesticide, RT-PCR, talaromyces, tolerance

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Authors: Sadaf Ilyas, Saba Riaz

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The extensive use of antibiotics has led to increases emergence of antibiotic-resistant organisms. Pseudomonas is a notorious opportunistic pathogen involoved in nosocomial infections and exhibit innate resistance to many antibiotics. The present study was conducted to assess the prevalence, levels of antimicrobial susceptibility and resistance mechanisms of Pseudomonas. A total of thirty clinical strains of Pseudomonas were isolated from different clinical sites of infection. All clinical specimens were collected from Chughtais Lahore Lab. Jail road, during 8-07-2010 to 11-01-2011. Biochemical characterization was done using routine biochemical tests. Antimicrobial susceptibility was determined by Kirby-Baeur method. The plasmids were isolated from all the strains and digested with restriction enzyme PstI and EcoRI. Transfer of Multi-resistance plasmid was checked via transformation and conjugation to confirm the plasmid mediated resistance to antibiotics. The prevalence of Pseudomonas in clinical specimens was found out to be 14% of all bacterial infections. IPM has shown to be the most effective drug against Pseudomonas followed by CES, PTB and meropenem, wheareas most of the Pseudomonas strains have developed significant resistance against Penicillins and some Cephalasporins. Antibiotic resistance determinants were carried by plasmids, as they conferred resistance to transformed K1 strains. The isolates readily undergo conjugation, transferring the resistant genes to other strains, illustrating the high rates of cross infection and nosocomial infection in the immunocompromised patients.

Keywords: pseudomonas, antibiotics, drug resistance, horizontal gene transfer

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Authors: M. G. Shehata, S. A. El Sohaimy, Marwa M. Abu-Serie, Nourhan M. Abd El-Aziz

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Probiotic strains can potentially be used as bio-preservatives and functional food supplement. Eight lactic acid bacteria strains (LAB) Lactobacillus brevis NRRL B-4527; Streptococcus thermophilus BLM 58; Pediococcusacidilactici ATCC 8042; Lactobacillus rhamnosus CCUG 1452; Lactobacillus curvatus ATCC 51436; Lactococcuslactis sub sp. lactisDSM 20481; Lactobacillus plantarum DMSZ 20079 and Lactobacillus plantarumTF103 were selected to screen the antioxidant, anticancer potential and probiotic properties. LAB strains exhibited good probiotic, antioxidant properties and showed antagonistic activity against food-borne pathogenic (Bacillus subtilis DB 100 host; Candida albicans ATCCMYA-2876; Clostridium botulinum ATCC 3584; Escherichia coli BA 12296; Klebsiellapneumoniae ATCC12296; Salmonella senftenberg ATCC 8400 and Staphylococcus aureus NCTC 10788). Further, in vitro probiotic properties of eight strains displayed excellent acid tolerance, bile tolerance, simulated gastrointestinal juice tolerance, in vitro adhesion ability for HT-29 cell line. The antioxidant effect of intracellular and cell-free extract of lactic acid bacteria strains was evaluated by various antioxidant assays, namely, resistance to hydrogen peroxide, DPPH radical scavenging, ABTS radical scavenging, and hydroxyl radical scavenging (HRS). The results showed that intracellular and cell-free supernatant of S. Thermophilus BLM 58, L. lactissubsp.lactis DSM 20481, P. acidilactici ATCC 8042, L. brevis NRRL B-4527 strains possess excellent antioxidant capacity. The intracellular of S. Thermophilus BLM 58 and P. acidilactici ATCC 8042 also showed excellent anticancer activity against Caco-2, MCF-7, HepG-2, and PC-3. Antioxidative property of selected lactic acid bacteria strains would be useful in the functional food manufacturing industry. They could beneficially affect the consumer by providing dietary source of antioxidants.

Keywords: anticancer activity, antioxidant activity, functional food, lactic acid bacteria, probiotic

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Authors: Daomao Yang, Qizhi Wang

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Monoterpenoids are mainly found in plant essential oils and they are ideal substrates for biotransformation into oxygen-containing derivatives with important commercial value due to their low price and simple structure. In this paper, eleven strains of endophytic fungi from Praxelis clematidea were used as test strains to conduct the whole cell biotransformation of the monoterpenoids: (+)-limonene, (-)-limonene and myrcene. The fungi were inoculated in 50 ml Sabouraud medium and incubated at 30 ℃ with the agitation of 150 r/min for 6 d, and then 0.5% (v/v) substrates were added into the medium and biotransformed for further 3 d. Afterwards the cultures were filtered, and extracted using equal volume of ethyl acetate. The metabolites were analyzed by GC-MS technique with NIST database. The Total Ion Chromatogram of the extractions from the eleven strains showed that the main product of (+)- and (-)-limonene biotransformation was limonene-1,2-diol, while it is limonene and linalool oxide for biotransformation of myrcene. This work will help screen the microorganisms to biotransform the monoterpenes.

Keywords: endophytic fungi, (+)–limonene, (-)–limonene, myrcene

Procedia PDF Downloads 126

Authors: C. Girometta, S. Babbini, R. M. Baiguera, D. S. Branciforti, M. Cartabia, D. Dondi, M. Pellegrini, A. M. Picco, E. Savino

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Interest on wood decay fungi (WDF) has been increasing in the last year's thanks to the potentiality of this kind of fungi; research on new WDF strains has increased as well thus pointing out the key role of the culture collections. One of the most recent biotechnological application of WDF is the development of novel materials from natural or recycled resources. Based on different combinations of fungal species, substrate, and processing treatment involved (e.g. heat pressing), it is possible to achieve a wide variety of materials with different features useful for many industrial applications: from packaging to thermal and acoustic insulation. In comparison with the conventional ones, these materials represent a 100% natural and compostable alternative involving low amounts of energy in the production process. The purpose of the present work was to isolate and select WDF strains able to colonize and degrade different plant wastes thus producing a fungal biomass shapeable to achieve bio-composite materials. Strains were selected within the mycological culture collection of Pavia University (MicUNIPV, over 300 strains of WDF). The selected strains have been investigated with regards their ability to colonize and degrade plant residues from the local major cultivations (e.g. poplar, alfalfa, maize, rice, and wheat) and produce the fungal biomass. The degradation of the substrate was assessed by Thermogravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). Chemical characterization confirmed that TGA and FTIR are complementary techniques able to provide quality-quantitative information on compositional and structural variation that occurs during the transformation from the substrate to the bio-composite material. This pilot study provides a fundamental step to tune further applications in fungus-residues composite biomaterials.

Keywords: bio-composite material, lignocellulosic residues, sustainable materials, wood decay fungi

Procedia PDF Downloads 141

Authors: Recep Keşli, Gülşah Aşık, Cengiz Demir, Onur Türkyılmaz

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Objective: Proteus mirabilis (P. mirabilis) is one of Gram-negative pathogens in human and it causes urinary tract and nosocomial infections. P. mirabilis is susceptible to β-lactams, aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole. It was aimed to investigate the resistance status to antimicrobial agents of Proteus mirabilis strains produced from samples sent to Afyon Kocatepe University, ANS Research and Practice Hospital, Microbiology Laboratory from different clinics and polyclinics during the period of 24 months. Methods: Between October 2013 and September 2015, a total of 30 Proteus were isolated from clinical samples of patients were hospitalized in intensive care units and in various departments of Afyon Kocatepe University, ANS Research and Practice Hospital. Identification of the bacteria was determined by conventional methods and VITEK 2 system (bioMérieux, France) was used additionally. Antibacterial susceptibility tests were performed by Kirby Bauer disc (Oxoid, Hempshire, England) diffusion method following the recommendations of CLSI. Results: Of the total 30 Proteus strains isolated from clinical samples, 19 from urine, 7 from wound, 4 from tracheal aspiration materials were isolated. Antimicrobial resistant for these strains were determined to 24,3% for meropenem, 26.2% for imipenem, 20.2% for amikacin 10.5% for cefepim, 33.3% for ciprofloxacin and levofloxacine, 31.6% for ceftazidime, 20% for ceftriaxone, 15.2% for gentamicin and 26.6% for amoxicillin-clavulanate, 26.2% trimethoprim-sulfamethoxale. Conclusion: In the present study, the highest number of clinical isolates of P. mirabilis were isolated from urine (63,3%), followed by the others (36,6%). The distribution of samples P. mirabilis strains to the clinics were as fallows; 16,8% intensive care unit (ICU), 29,9% polyclinics, 53,3% hospital service units The most effective antibiotic on the total of strains were found to be cefepim, the least effective antibiotics on the total of strains were found to be trimethoprim-sulfamethoxale.

Keywords: proteus mirabilis, antibiotic resistance, intensive care unit, Proteus spp.

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Authors: Mulue Girmay Gebreslasie

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Entomopathogenic fungi are naturally safe and eco-friendly biological agents. Their potential of host specificity and ease handling made them appealing options to substitute synthetic pesticides in pest control programs. However, they are highly delicate and unstable under field conditions. Therefore, the current experiment was held to search out persistent fungal strains by defining the relationship between invitro heat tolerance and field persistence. Current results on leaf and soil persistence assay revealed that strains of Metarhizium species, M. pingshaense (F2685), M. pingshaense (MS2) and M. brunneum (F709) exhibit maximum cumulative CFUs count, relative survival rate and least percent of CFUs reductions showed significant difference at 7 days and 28 days post inoculations (dpi) in hot seasons from sampled soils and leaves and in cold season from soil samples. Whereas relative survival of B. brongniartii (TNO6) found significantly higher in cold weather leaf treatment application as compared to hot season and found as persistent as other fungal strains, while higher deterioration of fungal conidia seen with M. pingshaense (MS2). In the current study, strains of Beauveria brongniartii (TNO6) and Cordyceps javanica (Czy-LP) were relatively vulnerable in field condition with utmost colony forming units (CFUs) reduction and least survival rates. Further, the relationship of the two parameters (heat tolerance and field persistence) was seen with strong linear positive correlations elucidated that heat test could be used in selection of field persistent fungal strains for hot season applications.

Keywords: integrated pest management, biopesticides, Insect pathology and microbial control, entomology

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Authors: Abdelkarim Mahdhi, Fdhila Kais, Faouzi Lamari, Zeineb Hmila, Fathi Kamoun, Maria Ángeles Esteban, Amina Bakhrouf

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Aquaculture is the world’s fastest growing food-production sector. However, one of the most serious problems regarding the culture of marine fishes is the mortality associated with pathogenic bacteria that occurs in the critical phases of larval development. Conventional approaches, such as the use of antimicrobial drugs to control diseases, have had limited success in the prevention or cure of aquatic diseases. Promising alternatives to antibiotics are probiotics, which are food supplements consisting of live microorganisms that benefit the host organism. In the search for more effective and environmentally friendly treatments with probionts against pathogenic species in shrimp larval culture, the probiotic properties of Bacillus strains isolated from Artemia culture such as antibacterial activity, adhesion, pathogenicity, toxicity and the effect of marine stress on viability and survival were investigated, as well as the changes occurring in their properties. Analyses showed that these bacteria corresponded to the genus Bacillus sp. Antagonism and adherence assays revealed that these strains have an inhibitory effect against pathogenic bacteria in vitro and in vivo conditions and are fairly adherent. Challenge tests performed with Artemia larvae provided evidence that the tested Bacillus strains were neither pathogenic nor toxic to the host. The tested strains maintained their viability and their probiotic properties during the period of study. The results suggest that the tested strains have suffered changes allowing them to survive in seawater in the absence of nutrients and outside their natural host, identifying them as potential probiotic candidates for Artemia culture.

Keywords: bacillus, probiotic, cell viability, stress response

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Authors: Mohamed Al-Hazmi, Abdullah Al-Arfaj, Moussa Ihab

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Raw, unpasteurized milk can carry dangerous bacteria such as Salmonella, E. coli, and Listeria, which are responsible for causing numerous foodborne illnesses. The objective of this study was molecular characterization of shiga toxogenic E. coli in raw milk collected from different Egyptian governorates by multiplex PCR. During the period of 25th May to 25th October 2012, a total of 320 bulk-tank milk samples were collected from 10 cow farms located in different Egyptian governorates. Bacteriological examination of milk samples revealed the presence of E. coli organisms in 65 samples (20.3%), serotyping of the E. coli isolates revealed, 35 strains (10.94%) O111, 15 strains (4.69%) O157: H7, 10 strains (3.13%) O128 and 5 strains (1.56%) O119. Multiplex PCR for detection of shiga toxin type 2 and intimin genes revealed positive amplification of 255 bp fragment of shiga toxin type 2 gene and 384 bp fragment of intimin gene from all E. coli serovar O157: H7, while from serovar O111 were 25 (71.43%), 20 (57.14%) and from serovar O128 were 6 (60%), 8 (80%), respectively. The results of multiplex PCR assay are useful for identification of STEC possessing the eaeA and stx2 genes.

Keywords: raw milk, E. coli, multiplex PCR, Shiga toxin type 2, intimin gene

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Authors: W. Lakhdari, B. Doumendji-Mitich, A. Dahliz, S. Doumendji, Y. Bouchikh, R. M'lik, H. Hammi, A. Soud

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This work was done in order to fight against Brachytrupes megacephalus, a major pest in the Algerian oasis and promote one aspect of biological control against it. He wears a hand on the isolation and identification of indigenous fungi on imagos of this insect harvested in the station of INRAA Touggourt and secondly, the study of the pathogenicity of these strains fungal on this orthoptère adults. The results obtained showed the presence of six different species of entomopathogenic fungi, it is: Aspergillus flavus, Fusarium sp, Beauveria bassiana, Penicillium sp, Metharizium anisopliae and Aspergillus Niger. The pathogenicity test using fungi Beauveria bassiana strains and Metharizium anisopliae. On adult of B. megacephalus highlights the effectiveness of these strains of predatory adults, with a mortality rate approaching 100% after 11 days.

Keywords: biological control, brachytrupes megacephalus, entomopathogenic fungi, Southeastern Algeria

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Authors: Jayarama Reddy, Anand S., H., Sundaram, Jeldi Hemachandran

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Forty two strains of Trichoderma sp. were isolated from cultivated lands around Bangalore and analyzed for their antagonistic potential against Macrophomina phaseolina. The potential of biocontrol agents ultimately lies in their capacity to control pathogens in vivo. Bioefficacy studies were hence conducted using chickpea (Cicer arientum c.v. Annigeri) as an experimental plant by the roll paper towel method. Overall the isolates T6, T35, T30, and T25 showed better antagonistic potential in addition to enhancing plant growth. The production of chitinases to break down the mycelial cell walls of fungal plant pathogens has been implicated as a major cause of biocontrol activity. In order to study the mechanism of biocontrol against Macrophomina phaseolina, ten better performing strains were plated on media, amended with colloidal chitin and Sclerotium rolfsii cell wall extract. All the isolates showed chitinolytic activity on day three as well as day five. Production of endochitinase and exochitinase were assayed in liquid media using colloidal chitin amended broth. Strains T35 and T6 displayed maximum endochitinase and exochitinase activity. Although all strains exhibited cellulase activity, the quantum of enzyme produced was higher in T35 and T6. The results also indicate a positive correlation between enzyme production and bioefficacy.

Keywords: biocontrol, bioefficacy, cellulase, chitinase

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Authors: Saba Pajuhan, Afshin Farahbakhsh, S. M. M. Dastgheib

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Biosurfactants and bioemulsifiers are a structurally diverse group of surface-active molecules synthesized by microorganisms, they are amphipathic molecules which reduce surface and interfacial tensions and widely used in pharmaceutical, cosmetic, food and petroleum industries. In this paper, several methods of bioemulsifer synthesis and purification by Bacillus licheniformis strains (namely ACO1, PTCC 1595 and ACO4) were investigated. Strains were grown in nutrient broth with different conditions in order to get maximum production of bioemulsifer. The purification of bio emulsifier and the quality evaluation of the product was done by adding sulfuric acid (H₂SO₄) (98%), Ethanol or HCl to the solution followed by centrifuging. To determine the optimal conditions yielding the highest bioemulsifier production, the effect of various carbon and nitrogen sources, temperature, NaCl concentration, pH, O₂ levels, incubation time are indispensable and all of them were highly effective in bioemulsifiers production.

Keywords: biosurfactant, bioemulsifier, purification, surface tension, interfacial tension

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Authors: Saria Almarzook, Monika Reissmann, Gudrun Brockmann

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Due to its history, occurrence in different ecosystems and diverse using, the modern horse (Equus caballus) shows large variability in size, appearance, behavior and habits. At all times, breeders try to create groups (breeds, strains) representing high homology but showing clear differences in comparison to other groups. A great interest of analyzing phenotypic and genetic traits looking for real diversity and genetic uniqueness existents for Arabian horses in Syria. 90 Arabian horses from governmental research center of Arabian horses in Damascus were included. The horses represent three strains (Kahlawi, Saklawi, Hamdani) originated from different geographical zones. They were raised on the same farm, under stable conditions. Twelve phenotypic traits were measured: wither height (WH), croup width (CW), croup height (CH), neck girth (NG), thorax girth (TG), chest girth (ChG), chest depth (ChD), chest width (ChW), back line length (BLL), body length (BL), fore cannon length (FCL) and hind cannon length (HCL). The horses were divided into groups according to age (less than 2 years, 2-4 years, 4-9 years, over 9 years) and to sex (male, female). The statistical analyzes show that age has significant influence of WH while the strain has only a very limited effect. On CW, NG, BLL, FCL and HCL, there is only a significant influence of sex. Age has significant effect on CH and BL. All sources of classes have a significant effect on TG, ChG, ChD and ChW. Strain has a significant effect on the BL. These results provide first information for real biodiversity in and between the strains and can be used to develop the breeding work in the Arabian horse breed.

Keywords: Arabian horse, phenotypic traits, strains, Syria

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Authors: I. Savitskaya, A. Kistaubayeva, A. Zhubanova, I. Blavachinskaiya, D. Ibrayeva, M. Abdulzhanova, A. Otarbay, A.Isabekova

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This study was conducted for the investigation of number of cellulolytic bacteria and their ability in decomposition. Seven samples surface soil were collected on cellulose Zailiskii Alatau slopes. Cellulolitic activity of new strains of Bacillus, isolated from soil is determined. Isolated cellulose degrading bacteria were screened for determination of the highest cellulose activity by quantitative assay using Congo red, gravimetric assay and colorimetric DNS method trough of the determination of the parameters of sugar reduction. Strains are assigned to: B.subtilis, B.licheniformis, B. cereus and, В. megaterium. Bacillus strains consisting of several different types of cellulases have broad substrate specificity of cellulase complexes formed by them. Cellulolitic bacteria were recorded to have highest cellulase activity and selected for optimization of cellulase enzyme production.

Keywords: cellulose-degrading bacteria, cellulase complex, foothills soil, screening

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Authors: Sihame Amakrane, Zineb Ouahdi, Mohammed Salah, Said Belaaouad

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\This research explores the efficacy of novel pyrimidine derivatives on bacterial strains such as Escherichia coli, Staphylococcus aureus, and Myccobacterium tuberculosis, utilizing bending energy calculations. Of the 25 compounds examined, 13 displayed potent activity against all the bacterial strains under study, exhibiting bending energy measurements between -7.4 and -10.7 kcal/mol. The -7.4 kcal/mol value corresponds to the bending energy of the SA12 and SA13 compounds with the 2xct protein (Staphylococcus aureus), whereas the -10.7 kcal/molis linked with the bending energy of SA6 and SA11 compounds with the 6GAV protein (Myccobacterium tuberculosis). Further research will involve a QSAR (Quantitative Structure-Activity Relationship) study aimed at constructing a reliable model to combat the aforementioned bacterial strains and a molecular dynamics study to evaluate the stability of ligand-protein complexes.

Keywords: docking, QSAR, bending energy, e. coli

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Authors: K. B. M. Islam, Syeeda Shiraj-Um-Mahmuda, Afroj Jahan, A. A. Bhuiyan

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In Bangladesh, the use of imported probiotics in poultry is gradually being increased. But surprisingly, no probiotic bacteria have been isolated yet in Bangladesh despite the existence of scavenging native poultry as potential source that is seemingly more resistant to GIT infection as well as other diseases. Therefore, the study was undertaken to isolate, identify and characterize the potential probiotic Lactobacillus and Bifidobacteria strains from Bangladeshi indigenous poultry, and to evaluate their suitability to use in poultry industry. Crop and cecal samples from 61 healthy indigenous birds were used to isolate potential probiotics strains following conventional cultural methods. A total of 216 isolates were identified following physical, biochemical and molecular methods that belonged to the genus Lactobacillus and Bifidobacteria. An auto-aggregation test was performed for 180 and 136 isolated lactobacilli and bifidobacteria strains, respectively. Twelve lactobacilli isolates and 7 bifidobacteria isolates were selected because of their convenient aggregation. In vitro tests including antibacterial activity, resistance to low pH, hemolytic activities etc. were performed for evaluation of probiotic potential of each strain. Under the in vitro conditions and with respects to the probiotic traits, three lactobacilli; LS16, LS45, LS133 and two bifidobacteria, BS21 and BS90 were found to be potential probiotic strains. Thus, they are proposed to be evaluated for their in vivo probiotic properties. If the proposed strains are found suitable as the probiotics to be used in commercial poultry industry, it is expected that the local probiotics would be more beneficial and would save the huge amount of money that Bangladesh spends every year for the importation of such materials from abroad.

Keywords: Bangladeshi poultry, gut microbiota, lactic acid bacteria, scavenging chicken, GIT health

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Authors: Rama Devi Kyatham, D. Ashok, K. S. K. Rao Patnaik, Raju Bathula

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We have shown the importance of pyrazoles as anti-microbial chemical entities. These compounds have generally been considered significant due to their wide range of pharmacological acivities and their discovery motivates new avenues of research.The proposed pyrazoles were synthesized and evaluated for their anti-microbial activities. The Synthesized compounds were analyzed by different spectroscopic methods.

Keywords: pyrazoles, validation, resistant microbial strains, anti-microbial activities

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Authors: T. Warinpramote, J. Sanguanjeen, P. Pholphakwaen, S. Kittisorayut, J. Kerdtubtim, S. Palachote, M. Taweechotipatr

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Cholesterol is a type of lipid molecule which is the significant risk factor for coronary heart disease. Currently, there are many cholesterol-lowering alternative treatments especially bile salt hydrolase positive lactobacilli. BSH can cleave the peptide linkage of bile salt, which results in removal of the amino acid group from the steroid core and increases production of the new bile acid by using more cholesterol. The purpose of this study was to isolate, and screen probiotic characteristics of lactobacilli from fermented Thai foods and further investigated for their comparative BSH activity. The result showed that 2 of 81 Lactobacillus strains, JPK2-2 and JPK3-2, isolated from Brassica juncea (L.) had significantly exhibited high BSH activity. In addition, these Lactobacillus strains showed their results that the ability to tolerate acid and bile salt. Furthermore, the using of 16S rDNA sequencing for definitive microbial identifications showed that these 2 strains belong to Lactobacillus plantarum. In the future, the L. plantarum with BSH activity strains JPK2-2 and JPK3-2 may be the candidate probiotics for application in functional foods and dairy products to improve in the patient with cardiovascular diseases.

Keywords: Lactobacillus plantarum, probiotics, bile salt hydrolase, cholesterol-lowering, fermented Thai food

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Authors: Benselama Amel, Ounane S. Mohamed, Bekki Abdelkader

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A collection of 20 isolates from fresh Nodules of the legume plant Lablab purpureus was isolated. These isolates have been authenticated by seedling inoculation grown in jars containing sand. The results obtained after two months of culture have revealed that the 20 isolates (100% of the isolates) are able to nodulate their host plants. The results obtained were analyzed statistically by ANOVA using the software statistica and had shown that the effect of the inoculation has significantly improved all the growth parameters (the height of the plant and the dry weight of the aerial parts and roots, and the number of nodules). We have evaluated the tolerance of all strains of the collection to the major stress factors as the salinity, pH and extreme temperature. The osmotolerance reached a concentration up to 1710mm of NaCl. The strains were also able to grow on a wide range of pH, ranging from 4.5 to 9.5, and temperature, between 4°C and 40°C. Also, we tested the effect of the acidity, aluminum and ferric deficit on the Lablab-rhizobia symbiosis. Lablab purpureus has not been affected by the presence of high concentrations of aluminum. On the other hand, iron deficiency has caused a net decrease in the dry biomass of the aerial part. The results of all the phenotypic characters have been treated by the statistical Minitab software, the numerical analysis had shown that these bacterial strains are divided into two distinct groups at a level of similarity of 86 %. The SDS-PAGE was carried out to determine the profile of the total protein of the strains. The coefficients of similarity of polypeptide bands between the isolates and strains reference (Bradyrhizobium, Mesorizobium sp.) confirm that our strain belongs to the groups of rhizobia.

Keywords: SDS-PAGE, rhizobia, symbiosis, phenotypic characterization, Lablab purpureus

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Authors: E. Samain, T. Aussenac, D. van Tuinen, S. Selim

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Plant growth promoting rhizobacteria are known as potential biofertilizers and plant resistance inducers. The present work aims to study the durability of the resistance induced as a response to wheat seeds inoculation with PB2 and its influence by Z. tritici strains. The internal and external roots colonization have been determined in vitro, seven days post inoculation, by measuring the colony forming unit (CFU). In planta experimentations were done under controlled conditions included four wheat cultivars with different levels of resistance against Septoria Leaf Blotch (SLB) and four Z. tritici strains with high aggressiveness and resistance levels to fungicides. Plantlets were inoculated with PB2 at sowing and infected with Z. tritici at 3 leaves or tillering growth stages. The infection level with SLB was evaluated at 17 days post inoculation using real-time quantitative polymerase chain reaction (PCR). Results showed that PB2 has a high potential of wheat root external colonization (> 10⁶ CFU/g of root). However, the internal colonization seems to be cultivar dependent. Indeed, PB2 has not been observed as endophytic for one cultivar but has a high level of internal colonization with more than 104 CFU/g of root concerning the three others. Two wheat cultivars (susceptible and moderated resistant) were used to investigate PB2-induced resistance (PB2-IR). After the first infection with Z. tritici, results showed that PB2-IR has conferred a high protection efficiency (40-90%) against SLB in the two tested cultivars. Whereas the PB2-IR was effective against all tested strains with the moderate resistant cultivar, it was higher with the susceptible cultivar (> 64%) but against three of the four tested strains. Concerning the durability of the PB2-IR, after the second infection timing, it has been observed a significant decrease (10-59%) depending strains in the moderate resistant cultivar. Contrarily, the susceptible cultivar showed a stable and high protection level (76-84%) but against three of the four tested strains and interestingly, the strain that overcame PB2-IR was not the same as that of the first infection timing. To conclude, PB2 induces a high and durable resistance against Z. tritici. The PB2-IR is pathogen strain, plant growth stage and genotype dependent. These results may explain the loss of the induced resistance effectiveness under field conditions.

Keywords: induced resistance, Paenibacillus sp. strain B2, wheat genotypes, Zymoseptoria tritici

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Authors: Mohammadreza Hajialigol, Nargues Falahi Charkhabi, Fatemeh Shahryari, Saadat Sarikhani

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BACKGROUND AND OBJECTIVES Iran is the third producer of Persian walnut worldwide. However, its walnut trees have been under threat from decline during last decade. Walnut canker caused by B. nigrifluens and B. rubrifaciens was recorded in multiple regions of Iran. Furthermore, Brenneria rosae subsp. rosae and Gibbsiella quercinecans were recently recognized as responsible for walnut decline in northwestern Iran. This study aimed to identify the causal agent of walnut decline in Kermanshah and Isfahan. MATERIAL AND METHODS Symptomatic samples were collected from affected walnut trees of Kermanshah and Isfahan provinces. The pathogenicity of strains was proved on immature walnut fruits cv. ‘Hartley’ and young green twigs of two-year-old walnut seedling cv. ‘Chandler’. Pathogenic strains were subjected to conventional phenotypic tests. 16S rRNA, gyrB, and infB genes were partially amplified and sequenced. RESULTS Irregular longitudinal cankers and dark lesions were observed in the outer and inner bark, respectively. Twenty-four strains were isolated on EMB-agar media. Fourteen strains were able to cause necrosis and a dark-colored region in the mesocarp and on young green twigs around the inoculation site 14 and 30 days post-inoculation, respectively. Strains were able to hydrolyze Tween 20, Tween 80, gelatin and esculin, however, did not produce indole or urease. Pairwise comparison, the 16S rRNA gene nucleotide sequences of strain I2 were 100% identical with those of Rahnella victoriana FRB 225T. Moreover, a phylogenetic tree reconstructed based on the concatenated sequences of two housekeeping gene fragments, gyrB (601 bp) and infB (615 bp), revealed that the strains I2, I5, and KE6 were clustered with R. victoriana FRB 225T. CONCLUSION To the best of our knowledge, this is the first report of R. victoriana in association with walnut decline. This result is necessary to find resistant genotypes.

Keywords: emerging pathogens, Iran, juglans regia, MLSA

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Authors: Beata Lachtara, Renata Szewczyk, Katarzyna Bielinska, Kinga Wieczorek, Jacek Osek

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Listeria monocytogenes is an important human and animal pathogen that causes foodborne outbreaks. The bacteria may be present in different types of food: cheese, raw vegetables, sliced meat products and vacuum-packed sausages, poultry, meat, fish. The most common method, which has been used for the investigation of genetic diversity of L. monocytogenes, is PFGE. This technique is reliable and reproducible and established as gold standard for typing of L. monocytogenes. The aim of the study was characterization by molecular serotyping and PFGE analysis of L. monocytogenes strains isolated from fresh fish and fish products in Poland. A total of 301 samples, including fresh fish (n = 129) and fish products (n = 172) were, collected between January 2014 and March 2016. The bacteria were detected using the ISO 11290-1 standard method. Molecular serotyping was performed with PCR. The isolates were tested with the PFGE method according to the protocol developed by the European Union Reference Laboratory for L. monocytogenes with some modifications. Based on the PFGE profiles, two dendrograms were generated for strains digested separately with two restriction enzymes: AscI and ApaI. Analysis of the fingerprint profiles was performed using Bionumerics software version 6.6 (Applied Maths, Belgium). The 95% of similarity was applied to differentiate the PFGE pulsotypes. The study revealed that 57 of 301 (18.9%) samples were positive for L. monocytogenes. The bacteria were identified in 29 (50.9%) ready-to-eat fish products and in 28 (49.1%) fresh fish. It was found that 40 (70.2%) strains were of serotype 1/2a, 14 (24.6%) 1/2b, two (4.3%) 4b and one (1.8%) 1/2c. Serotypes 1/2a, 1/2b, and 4b were presented with the same frequency in both categories of food, whereas serotype 1/2c was detected only in fresh fish. The PFGE analysis with AscI demonstrated 43 different pulsotypes; among them 33 (76.7%) were represented by only one strain. The remaining 10 profiles contained more than one isolate. Among them 8 pulsotypes comprised of two L. monocytogenes isolates, one profile of three isolates and one restriction type of 5 strains. In case of ApaI typing, the PFGE analysis showed 27 different pulsotypes including 17 (63.0%) types represented by only one strain. Ten (37.0%) clusters contained more than one strain among which four profiles covered two strains; three had three isolates, one with five strains, one with eight strains and one with ten isolates. It was observed that the isolates assigned to the same PFGE type were usually of the same serotype (1/2a or 1/2b). The majority of the clusters had strains of both sources (fresh fish and fish products) isolated at different time. Most of the strains grouped in one cluster of the AscI restriction was assigned to the same groups in ApaI investigation. In conclusion, PFGE used in the study showed a high genetic diversity among L. monocytogenes. The strains were grouped into varied clonal clusters, which may suggest different sources of contamination. The results demonstrated that 1/2a serotype was the most common among isolates from fresh fish and fish products in Poland.

Keywords: Listeria monocytogenes, molecular characteristic, PFGE, serotyping

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Authors: Gajanan V. Mane, Rashmi More, Mahesh S. Sonawane, Tushar Lodha, Rohit Sharma

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The diversity of fungi isolated from two different termite species viz., Odontoterms assmuthi and O. abesus was investigated by dilution- plate method, combined with morphological characteristics and sequencing of internal transcribed spacer region. In total, ninety-six fungi were isolated and purified, out of which 69 isolates were obtained from O. assmuthi belonging to 18 genera and 31 species, whereas 27 isolates were obtained from O. abesus belonging to 15 genera and 17 species. The fungal strains were screened for laccase, amylase, cellulase and pectinase enzymes production. Twenty-seven strains were positive for laccase, 59 strains were positive for amylase, 71 strains were positive for cellulase and 72 strains were positive for pectinase enzymes. The antimicrobial activities of the isolated fungi were tested by the dual plate culture method against standard pathogens. Bioactive secondary metabolites were identified by HPLC and LCMS. Four isolates viz., Penicillium goetzii MG 57, Epicoccum sp. MG 39, Penicillium tanzanicum MG 30, Aspergillus polyporicola MG 54, showed positive antimicrobial activity against standard pathogens, Streptococcus pneumonia MCC 2425, Staphylococcus aureus MCC 2408, Pseudomonas aeruginosa MCC 2080, Escherichia coli MCC 2412, Enterococcus faecalis MCC 2409, Klebsiella pneumonia MCC 2451, Micrococcus luteus MCC 2155 and Candida albicans MCC 1151. In conclusion, the study showed that the insect gut harbor fungal diversity, which is futuristic with biotechnological potential and could be a good source of enzymes and antibiotics.

Keywords: termites, fungi, its, enzyme, antimicrobial activity

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