Search results for: Bacteria Foraging

Authors: Kyaw Myo Lin, Wunna Swe, Pyone Lai Swe

Abstract:

This paper presents the coordinated controller design of static synchronous compensator (STATCOM) and power system stabilizers (PSSs) for power system stability improvement. Coordinated design problem of STATCOM-based controller with multiple PSSs is formulated as an optimization problem and optimal controller parameters are obtained using bacteria foraging optimization algorithm. By minimizing the proposed objective function, in which the speed deviations between generators are involved; stability performance of the system is improved. The nonlinear simulation results show that coordinated design of STATCOM-based controller and PSSs improve greatly the system damping oscillations and consequently stability improvement.

Keywords: Bacteria Foraging, Coordinated Design, Power System Stability, PSSs, STATCOM.

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Authors: Florin Leon, Silvia Curteanu

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The Bacterial Foraging Optimization (BFO) algorithm is inspired by the behavior of bacteria such as Escherichia coli or Myxococcus xanthus when searching for food, more precisely the chemotaxis behavior. Bacteria perceive chemical gradients in the environment, such as nutrients, and also other individual bacteria, and move toward or in the opposite direction to those signals. The application example considered as a case study consists in establishing the dependency between the reaction yield of hydrogels based on polyacrylamide and the working conditions such as time, temperature, monomer, initiator, crosslinking agent and inclusion polymer concentrations, as well as type of the polymer added. This process is modeled with a neural network which is included in an optimization procedure based on BFO. An experimental study of BFO parameters is performed. The results show that the algorithm is quite robust and can obtain good results for diverse combinations of parameter values.

Keywords: Bacterial foraging optimization, hydrogels, neural networks, modeling.

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Authors: K. Geetha, P. Thangaraj, C. Rasi Priya, C. Rajan, S. Geetha

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This paper presents the performance of Integrated Bacterial Foraging Optimization and Particle Swarm Optimization (IBFO_PSO) technique in MANET routing. The BFO is a bio-inspired algorithm, which simulates the foraging behavior of bacteria. It is effectively applied in improving the routing performance in MANET. In results, it is proved that the PSO integrated with BFO reduces routing delay, energy consumption and communication overhead.

Keywords: Ant Colony Optimization, Bacterial Foraging Optimization, Hybrid Routing Intelligent Algorithm, Naturally inspired algorithms, Particle Swarm Optimization.

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Authors: Jagabondhu Hazra, Avinash Sinha

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Economic dispatch problem is an optimization problem where objective function is highly non linear, non-convex, non-differentiable and may have multiple local minima. Therefore, classical optimization methods may not converge or get trapped to any local minima. This paper presents a comparative study of four different evolutionary algorithms i.e. genetic algorithm, bacteria foraging optimization, ant colony optimization and particle swarm optimization for solving the economic dispatch problem. All the methods are tested on IEEE 30 bus test system. Simulation results are presented to show the comparative performance of these methods.

Keywords: Ant colony optimization, bacteria foraging optimization, economic dispatch, evolutionary algorithm, genetic algorithm, particle swarm optimization.

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Authors: S. Bougrine, S. Ouchraa, B. Ahiod, A. A. El Imrani

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Ant colony optimization is an ant algorithm framework that took inspiration from foraging behavior of ant colonies. Indeed, ACO algorithms use a chemical communication, represented by pheromone trails, to build good solutions. However, ants involve different communication channels to interact. Thus, this paper introduces the acoustic communication between ants while they are foraging. This process allows fine and local exploration of search space and permits optimal solution to be improved.

Keywords: Acoustic Communication, Ant Colony Optimization, Local Search, Traveling Salesman Problem.

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Authors: R. Satish, G. Raja Rao

Abstract:

In this paper a hybrid distributed generation (DG) system connected to isolated load is studied. The DG system consisting of photo voltaic (PV) system, fuel cells, aqua electrolyzer, diesel engine generator and a battery energy storage system. The ambient temperature value of PV is taken as constant to make the output power of PV is directly proportional to the radiation and output power of other DG sources and frequency of the system is controlled by simple integral (I), proportional plus integral (PI), and proportional plus integral and derivative(PID) controllers. A maiden attempt is made to apply a more recent and powerful optimization technique named as bacterial foraging technique for optimization of controllers gains of the proposed hybrid DG system. The system responses with bacterial foraging based controllers are compared with that of classical method. Investigations reveal that bacterial foraging based controllers gives better responses than the classical method and also PID controller is best. Sensitivity analysis is carried out which demonstrates the robustness of the optimized gain values for system loading condition.

Keywords: Aqua electrolyzer, bacterial foraging, battery energy storage system, diesel engine generator, distributed generation, fuel cells, photo voltaic system.

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Authors: A. Rajagopal, S. Somasundaram, B. Sowmya, T. Suguna

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Wireless Sensor Networks (WSNs) enable new applications and need non-conventional paradigms for the protocol because of energy and bandwidth constraints, In WSN, sensor node’s life is a critical parameter. Research on life extension is based on Low-Energy Adaptive Clustering Hierarchy (LEACH) scheme, which rotates Cluster Head (CH) among sensor nodes to distribute energy consumption over all network nodes. CH selection in WSN affects network energy efficiency greatly. This study proposes an improved CH selection for efficient data aggregation in sensor networks. This new algorithm is based on Bacterial Foraging Optimization (BFO) incorporated in LEACH.

Keywords: Bacterial Foraging Optimization (BFO), Cluster Head (CH), Data-aggregation protocols, Low-Energy Adaptive Clustering Hierarchy (LEACH).

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Authors: I. V. N. Rathnayake, Mallavarapu Megharaj, Nanthi Bolan, Ravi Naidu

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With the intention of screening for heavy metal tolerance, a number of bacteria were isolated and characterized from a pristine soil. Two Gram positive isolates were identified as Paenibacillus sp. and Bacillus thuringeinsis. Tolerance of Cd2+, Cu2+ and Zn2+ by these bacteria was studied and found that both bacteria were highly sensitive to Cu2+ compared to other two metals. Both bacteria showed the same pattern of metal tolerance in the order Zn+ > Cd2+ > Cu2+. When the metal tolerance in both bacteria was compared, Paenibacillus sp. showed the highest sensitivity to Cu2+ where as B. thuringiensis showed highest sensitivity to Cd2+ and Zn2+ .These findings revealed the potential of Paenibacillus sp. in developing a biosensor to detect Cu2+ in environmental samples.

Keywords: Heavy metals, bacteria, soil, tolerance.

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Authors: Abdollah Hosseini, Abbas Maleki, Khalil Fasihi, Rahim Naseri

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In order to investigate the effect of Plant Growth Promoting Rhizobacteria (PGPR) and rhizobium bacteria on grain yield and some agronomic traits of mungbean (Vigna radiate L.), an experiment was carried out based on randomized complete block design with three replications in Malekshahi, Ilam province, Iran during 2012-2013 cropping season. Experimental treatments consisted of control treatment, inoculation with rhizobium bacteria, rhizobium bacteria and Azotobacter, rhizobium bacteria and Azospirillum, rhizobium bacteria and Pseudomonas, rhizobium bacteria, Azotobacter and Azospirillum, rhizobium bacteria, Azotobacter and Pseudomonas, rhizobium bacteria, Azospirillum and Pseudomonas and rhizobium bacteria, Azotobacter, Azospirillum and Pseudomonas. The results showed that the effect of PGPR and rhizobium bacteria were significant affect on grain and its components in mungbean plant. Grain yield significantly increased by PGPR and rhizobium bacteria, so that the maximum grain yield was obtained from rhizobium bacteria + Azospirillum + Pseudomonas with the amount of 2287 kg.ha-1 as compared to control treatment. Excessive application of chemical fertilizers causes environmental and economic problems. That is, the overfertilization of P and N leads to pollution due to soil erosion and runoff water, so the use of PGPR and rhizobium bacteria can be justified due to reduce input costs, increase in grain yield and environmental friendly.

Keywords: Azotobacter, Mungbean, Pseudomonas, Rhizobium bacteria.

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Authors: Togzhan D. Mukasheva, Anel A. Omirbekova, Raikhan S. Sydykbekova, Ramza Zh. Berzhanova, Lyudmila V. Ignatova

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Following plants-barley (Hordeum sativum), alfalfa (Medicago sativa), grass mixture (red fescue-75%, long-term ryegrass - 20% Kentucky bluegrass - 10%), oilseed rape (Brassica napus biennis), resistant to growth in the contaminated soil with oil content of 15.8 g / kg 25.9 g / kg soil were used. Analysis of the population showed that the oil pollution reduces the number of bacteria in the rhizosphere and rhizoplane of plants and enhances the amount of spore-forming bacteria and saprotrophic micromycetes. It was shown that regardless of the plant, dominance of Pseudomonas and Bacillus genera bacteria was typical for the rhizosphere and rhizoplane of plants. The frequency of bacteria of these genera was more than 60%. Oil pollution changes the ratio of occurrence of various types of bacteria in the rhizosphere and rhizoplane of plants. Besides the Pseudomonas and Bacillus genera, in the presence of hydrocarbons in the root zone of plants dominant and most typical were the representatives of the Mycobacterium and Rhodococcus genera. Together the number was between 62% to 72%.

Keywords: Identification, micromycetes, pollution, root system.

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Authors: Sawangjit Sopid

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In this study sugarcane field soils with a long history of atrazine application in Chachoengsao and Chonburi provinces have been explored for their potential of atrazine biodegradation. For the atrazine degrading bacteria isolation, the soils used in this study named ACS and ACB were inoculated in MS-medium containing atrazine. Six short rod and gram-negative bacterial isolates, which were able to use this herbicide as a sole source of nitrogen, were isolated and named as ACS1, ACB1, ACB3, ACB4, ACB5 and ACB6. From the 16S rDNA nucleotide sequence analysis, the isolated bacteria ACS1 and ACB4 were identified as Rhizobium sp. with 89.1-98.7% nucleotide identity, ACB1 and ACB5 were identified as Stenotrophomonas sp. with 91.0-92.8% nucleotide identity, whereas ACB3 and ACB6 were Klebsiella sp. with 97.4-97.8% nucleotide identity.

Keywords: Atrazine-degrading bacteria, bioremediation, Thai isolate bacteria.

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Authors: A. Elragig, S. Townley, H. Dreiwi

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In this paper we introduce a bacteria-leukocyte model with bacteria chemotaxsis. We assume that bacteria develop a tactic defence mechanism as a response to Leukocyte phagocytosis. We explore the effect of this tactic motion on Turing space in two parameter spaces. A fine tuning of bacterial chemotaxis shows a significant effect on developing a non-uniform steady state.

Keywords: Chemotaxis-diffusion driven instability, bacterial chemotaxis.

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Authors: E. Marei, A. Hammad, S. Ismail, A. El-Gindy

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This study aims to investigate the ability of different formula of mixed bacteria as a biological treatments of wastewater after primary treatment as a bio-treatment and bio-removal and bio-adsorbent of different heavy metals in natural circumstances. The wastewater was collected from Sarpium forest site-Ismailia Governorate, Egypt. These treatments were mixture of free cells and mixture of immobilized cells of different bacteria. These different formulas of mixed bacteria were prepared under Lab. condition. The obtained data indicated that, as a result of wastewater bio-treatment, the removal rate was found to be 76.92 and 76.70% for biological oxygen demand, 79.78 and 71.07% for chemical oxygen demand, 32.45 and 36.84 % for ammonia nitrogen as well as 91.67 and 50.0% for phosphate after 24 and 28 hrs with mixed free cells and mixed immobilized cells, respectively. Moreover, the bio-removals of different heavy metals were found to reach 90.0 and 50. 0% for Cu ion, 98.0 and 98.5% for Fe ion, 97.0 and 99.3% for Mn ion, 90.0 and 90.0% Pb, 80.0% and 75.0% for Zn ion after 24 and 28 hrs with mixed free cells and mixed immobilized cells, respectively. The results indicated that 13.86 and 17.43% of removal efficiency and reduction of total dissolved solids were achieved after 24 and 28 hrs with mixed free cells and mixed immobilized cells, respectively.

Keywords: Biological desalination, bio-sorption heavy metals, free cell bacteria, immobilized bacteria, wastewater bio-treatment.

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Authors: A. Fazilah, I. Darah, I. Noraznawati

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Three different bacteria capable of degrading phenanthrene were isolated from hydrocarbon contaminated site. In this study, the phenanthrene-degrading activity by defined monoculture was determined and mixed culture was identified as Acinetobacter sp. P3d, Bacillus sp. P4a and Pseudomonas sp. P6. All bacteria were able to grow in a minimal salt medium saturated with phenanthrene as the sole source of carbon and energy. Phenanthrene degradation efficiencies by different combinations (consortia) of these bacteria were investigated and their phenanthrene degradation was evaluated by gas chromatography. Among the monocultures, Pseudomonas sp. P6 exhibited 58.71% activity compared to Acinetobacter sp. P3d and Bacillus sp. P4a which were 56.97% and 53.05%, respectively after 28 days of cultivation. All consortia showed high phenanthrene elimination which were 95.64, 79.37, 87.19, 79.21% for Consortia A, B, C and D, respectively. The results indicate that all of the bacteria isolated may effectively degrade target chemical and have a promising application in bioremediation of hydrocarbon contaminated soil purposes.

Keywords: Acinetobacter sp. P3d, Bacillus sp. P4a, consortia, phenanthrene, Pseudomonas sp. P6.

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Authors: Santi Behera, M. Tripathy, J. K. Satapathy

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Power systems are operating under stressed condition due to continuous increase in demand of load. This can lead to voltage instability problem when face additional load increase or contingency. In order to avoid voltage instability suitable size of reactive power compensation at optimal location in the system is required which improves the load margin. This work aims at obtaining optimal size as well as location of compensation in the 39- bus New England system with the help of Bacteria Foraging and Genetic algorithms. To reduce the computational time the work identifies weak candidate buses in the system, and then picks only two of them to take part in the optimization. The objective function is based on a recently proposed voltage stability index which takes into account the weighted average sensitivity index is a simpler and faster approach than the conventional CPF algorithm. BFOA has been found to give better results compared to GA.

Keywords: BFOA, GA, SSVSL, WASI.

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Authors: Saif N. Al-Bahry, Yahya M. Al-Wahaibi, Abdulkadir E. Elshafie, Ali S. Al-Bemani, Sanket J. Joshi

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Environmental pollution is a global problem and best possible solution is identifying and utilizing native microorganisms. One possible application of microbial product -biosurfactant is in bioremediation of hydrocarbon contaminated sites. We have screened forty two different petroleum contaminated sites from Oman, for biosurfactant producing spore-forming bacterial isolates. Initial screening showed that out of 42 soil samples, three showed reduction in surface tension (ST) and interfacial tension (IFT) within 24h of incubation at 40°C. Out of those 3 soil samples, one was further selected for isolation of bacteria and 14 different bacteria were isolated in pure form. Of those 14 spore-forming, rod shaped bacteria, two showed highest reduction in ST and IFT in the range of 70mN/m to <35mN/m and 26.69mN/m to <9mN/m, respectively within 24h. These bacterial biosurfactants may be utilized for bioremediation of oil-spills.

Keywords: Bioremediation, biosurfactant, hydrocarbon pollution, spore-forming bacteria.

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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: A. R. Shirazinejad, I. Noryati, A. Rosma, I. Darah

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Lactic acid alone and its combined application with nisin were evaluated for reducing population of naturally occurring microorganisms on chilled shrimp. Fresh shrimps were dipped in 0, 1.0% and 2.0% (v/v) lactic acid alone and their combined application with 0.04 (g/L/kg) nisin solution for 10 min. Total plate counts of aerobic bacteria (TPCs), Psychrotrophic counts, population of Pseudomonas spp., H2S producing bacteria and Lactic acid bacteria (LAB) on shrimps were determined during storage at 4 °C. The results indicated that total plate counts were 2.91 and 2.63 log CFU/g higher on untreated shrimps after 7 and 14 days of storage, respectively, than on shrimps treated with 2.0% lactic acid combined with 0.04 (g/L/kg) nisin. Both concentrations of lactic acid indicated significant reduction on Pseudomonas counts during storage, while 2.0% lactic acid combined with nisin indicated the highest reduction. In addition, H2S producing bacteria were more sensitive to high concentration of lactic acid combined with nisin during storage.

Keywords: Shrimp, lactic acid, nisin, spoilage bacteria

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Authors: Noor Muzamil Mohamad, Abdul Manaf Ali, Hamzah Mohd Salleh

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Phytases (myo-inositol hexakisphosphate phosphohydrolases; EC 3.1.3.8) catalyze the hydrolysis of phytic acid (myoinositol hexakisphosphate) to the mono-, di-, tri-, tetra-, and pentaphosphates of myo-inositol and inorganic phosphate. Therrmophilic bacteria isolated from water sampled from hot spring. About 120 isolates of bacteria were successfully isolated form hot spring water sample and tested for extracellular phytase producing. After 5 passages of the screening on the PSM media, 4 isolates were found stable in producing phytase enzyme. The 16s RDNA sequencing for identification of bacteria using molecular technique revealed that all isolates those positive in phytase producing are belong to Geobacillus spp. And Anoxybacillus spp. Anoxybacillus rupiensis UniSZA-7 were identified for their carbon source utilization using Phenotype Microarray Plate of Biolog and found they utilize several kind of carbon source provided.

Keywords: Phytase, Phytic Acid, Thermophilic Bacteria, PSM Media and Phytase Assay

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Authors: Phanwipa Pangsri, Yawariyah Weahayee

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The lactic acid bacteria (LAB) were isolated from 10 samples of fermented foods (Sa-tor-dong and Bodo) in South locality of Thailand. The 23 isolates of lactic acid bacteria were selected, which were exhibited a clear zone and growth on MRS agar supplemented with CaCO3. All of lactic acid bacteria were tested on morphological and biochemical. The result showed that all isolates were Gram’s positive, non-spore forming but only 10 isolates displayed catalase negative. The 10 isolates including BD1 .1, BD 1.2, BD 2.1, BD2.2, BD 2.3, BD 3.1, BD 4.1, BD 5.2, ST 4.1 and ST 5.2 were selected for inhibition activity determination. Only 2 strains (ST 4.1 and BD 2.3) showed inhibition zone on agar, when using Escherichia coli sp. as target strain. The ST 4.1 showed highest inhibition zone on agar, which was selected for probiotic property testing. The ST4.1 isolate could grow in MRS broth containing a high concentration of sodium chloride 6%, bile salts 7%, pH 4-10 and vary temperature at 15-45°C.

Keywords: Lactic acid bacteria, Probiotic, Antimicrobial.

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Authors: Wei-Soon Ng, Min-Lee Lee, Siew-Ling Hii

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Microbial-induced calcite precipitation (MICP) is a relatively green and sustainable soil improvement technique. It utilizes biochemical process that exists naturally in soil to improve engineering properties of soils. The calcite precipitation process is uplifted by the mean of injecting higher concentration of urease positive bacteria and reagents into the soil. The main objective of this paper is to provide an overview of the factors affecting the MICP in soil. Several factors were identified including nutrients, bacteria type, geometric compatibility of bacteria, bacteria cell concentration, fixation and distribution of bacteria in soil, temperature, reagents concentration, pH, and injection method. These factors were found to be essential for promoting successful MICP soil treatment. Furthermore, a preliminary laboratory test was carried out to investigate the potential application of the technique in improving the shear strength and impermeability of a residual soil specimen. The results showed that both shear strength and impermeability of residual soil improved significantly upon MICP treatment. The improvement increased with increasing soil density.

Keywords: Bacteria, biocementation, bioclogging, calcite precipitation, soil improvement.

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Authors: M. Shafighi, Z. Emami, M. Shahsanaei, E. Khaliliyan

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The aim of this study was to assess the effect of LAB isolated from Iranian native olives on the opportunistic skin pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Lactic Acid Bacteria were isolated from the brine of each sample in the prior of time. The samples were spread on MRS agar for isolation of lactobacillus and for lactococcus. 28 strains of labs were isolated. The labs were centrifuged, the supernatant was strewed and pellet was used to inoculation in wells or at blank disks. 20μl of each pellet was inoculated to blank disks and 40μl of each pellet was inoculated to each well. The result of disk and well diffusion agar against these pathogens were confirmed each other. The size of inhibition zone was different according to the type of bacteria, the method and the concentrations of labs.

Keywords: Olive, Probiotic, Lactic Acid Bacteria (LAB), P.aeroginosa and S.aureus

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Authors: Nelson R. Osungbemiro, Rafiu O. Sanni, Rotimi F. Olaniyan, Abayomi O. Olajuyigbe

Abstract:

Bacteria flora of Clarias gariepinus collected from two natural habitats namely Owena River (freshwater) and Igbokoda lagoon (brackish water) were examined using standard microbiological procedures. Thirteen bacterial species were identified. The result indicated that from the identified bacteria isolated, Vibrio sp, Proteus sp. Shigella sp. and E. coli were present in both habitats (fresh and brackish waters). Others were habitat-selective such as Salmonella sp., Pseudomonas sp, Enterococcus sp, Staphylococcus sp. that were found only in freshwater habitat. While Branhamella sp, Streptococcus sp. and Micrococcus sp. were found in brackish water habitat. Bacteria load from Owena river (freshwater) was found to be the highest load recorded at 6.21 x 10⁴cfu. T-test analysis also revealed that there was a marked significant difference between bacterial load in guts of sampled Clarias from fresh water and brackish water habitats.

Keywords: Bacteria flora, gut, Clarias gariepinus, Owena river

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Authors: P. O. Angienda, D. J. Hill

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The purpose of this study was to elucidate the factors affecting antimicrobial effectiveness of essential oils against food spoilage and pathogenic bacteria. The minimum inhibition concentrations (MIC) of the essential oils, were determined by turbidimetric technique using Biocreen C, analyzer. The effects of pH ranging from 7.3 to 5.5 in absence and presence of essential oils and/or NaCl on the lag time and mean generation time of the bacteria at 370C, were carried out and results were determined showed that, combination of low pH and essential oil at 370C had additive effects against the test micro-organisms. The combination of 1.2 % (w/v) of NaCl and clove essential oil at 0.0325% (v/v) was effective against E. coli. The use of concentrations less than MIC in combination with low pH and or NaCl has the potential of being used as an alternative to “traditional food preservatives".

Keywords: Antimicrobial, Bacteria, Bioscreen C, essential oil.

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Authors: Feng Zhou, Yuyan Wang

Abstract:

This study aimed to detect and to identify the main strains of airborne microorganisms present in the Shanghai Metro system. Samples were collected using agar plates exposed to the air and microorganisms were identified using catalase, plasma coagulase and hymolytic analysis. The results show that the concentration of mildew present within a newly opened metro line was significantly higher than for other lines. Differences among underground and elevated stations can be attributed to differences in passenger flow and the environment surrounding the stations. Additionally, the investigation indicated that bacteria reached maximum levels at different times on weekdays and weekends. The bacteria in the Metro stations were identified as primarily Gram positive, consisting mainly of coagulase-negative staphylococcus strains (CNS).

Keywords: Bacteria, environment, Metro system, mildew, passenger flow

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Authors: L. S. Markosyan, L. A. Ganushkina, N. S. Vardanyan, K. V. Harutyunova, M. V. Harutyunova

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Five original strains of entomopathogenic bacteria with insecticidal activity against mosquito larvae of the genera Aedes, Culex and Anopheles have been isolated from natural conditions in Armenia and characterized. According to morphological, physiological and biochemical parameters, all isolates were identified as Bacillus thuringiensis spp. israelensis (Bti). High larvicidal activity has been showed by three strains Bti. These strains can be recommended for industrial production of bacterial preparations.

Keywords: Armenia, Bacillus thuringiensis ssp. israelensis, bloodsucking mosquito control, new effective strains of bacteria.

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Authors: Ayuko Itsuki, Sachiyo Aburatani

Abstract:

The soil ecology of the organic and mineral soil layers of laurel-leaved and Cryptomeria japonica forest in the Kasuga-yama Hill Primeval Forest (Nara, Japan) was assessed. The number of bacteria obtained by the dilution plate count method was less than 0.05% of those counted by the direct microscopic count. We therefore found that forest soil contains large numbers of non-culturable bacteria compared with agricultural soils. The numbers of bacteria and fungi obtained by both the dilution plate count and the direct microscopic count were larger in the deeper horizons (F and H) of the organic layer than in the mineral soil layer. This suggests that active microbial metabolism takes place in the organic layer. The numbers of bacteria and the length of fungal hyphae obtained by the direct count method were greater in the H horizon than in the F horizon. The direct microscopic count revealed numerous non-culturable bacteria and fungi in the soil. The ratio of fungal to bacterial biomass was lower in the laurel-leaved forest soil. The fungal biomass was therefore relatively low in the laurel-leaved forest soil due to differences in forest vegetation.

Keywords: Bacterial number, Dilution plate count, Direct microscopic count, Forest soil.

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Authors: Laura Gjyli, Pirro Prifti, Lindita Mukli, Silvana Gjyli, Irida Ikonomi, Jerina Kolitari

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Microbial air contamination of the outdoor air in Marine Durres-s Harbour (Durres, Albania) was estimated by sedimentation technique in August-October 2008. The sampling areas were: Ferry Terminal (FT), Fishery Harbor (FH), East Zone (EZ), Fuel Quay (FQ) and Apollonian Beach (AB). The aim of this study was to measure the number of aerobic plate count (mesophilic aerobic bacteria) and fungi (yeasts and molds) in the outdoor air in these areas. The number of colonies that were formed determines the number of cells at the moment in the outdoor air; respectively the number of mesophilic aerobic bacteria and yeasts and molds. The measure of bacteria and fungi used is CFU (Colony Forming Units) per Petri dish. It is said that marine harbours are very polluted areas. The aim of study was the definition of mesophilic aerobic bacteria and yeasts and molds number, and the comparison of microorganisms number in air sampling areas.

Keywords: Air microbiology, colony forming units, Marine Durres's Harbour, mesophilic aerobic bacteria, outdoor air, yeasts and molds.

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Authors: Vu Thu Trang, Lam Xuan Thanh, Samira Sarter, Tomoko Shimamura, Hiroaki Takeuchi　

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Antimicrobial activities of aminoreductone (AR), a product formed in the initial stage of Maillard reaction, were screened against pathogenic bacteria. A significant growth inhibition of AR against all 7 isolates (Staphylococcus aureus ATCC® 25923™, Salmonella typhimurium ATCC® 14028™, Bacillus cereus ATCC® 13061™, Bacillus subtilis ATCC® 11774™, Escherichia coli ATCC® 25922™, Enterococcus faecalis ATCC® 29212™, Listeria innocua ATCC® 33090™) were observed by the standard disc diffusion methods. The inhibition zone for each isolate by AR (2.5 mg) ranged from 15±0mm to 28.3±0.4mm in diameter. The minimum inhibitory concentration (MIC) of AR ranging from 20mM to 26mM was proven in the 7 isolates tested. AR also showed the similar effect of growth inhibition in comparison with antibiotics frequently used for the treatment of infections bacteria, such as amikacin, ciprofloxacin, meropennem and levofloxacin. The results indicated that foods containing AR are valuable sources of bioactive compounds towards pathogenic bacteria.

Keywords: Pathogenic bacteria, aminoreductone, Maillard reaction, antimicrobial activity.

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Authors: Arpita Soni, Sapna Mittal

Abstract:

Austenite and Martensite indicate the phases of solids undergoing phase transformation which we usually associate with materials and not with living organisms. This article provides an overview of bacterial proteins and structures that are undergoing phase transformation and suggests its probable effect on mechanical behavior. The context is mainly within the role of phase transformations occurring in the flagellum of bacteria. The current knowledge of molecular mechanism leading to phase variation in living organisms is reviewed. Since in bacteria, each flagellum is driven by a separate motor, similarity to a Differential drive in case of four-wheeled vehicles is suggested. It also suggests the application of the mechanism in which bacteria changes its direction of movement to facilitate single point turning of a multi-wheeled vehicle. Finally, examples are presented to illustrate that the motion due to phase transformation of flagella in bacteria can start a whole new research on motion mechanisms.

Keywords: Flagella, Phase Transformation, Nanobots, Differential Drive, Single point turn, Biomimetics

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