Application of Lactic Acid Bacteria(LAB) in Freshness Keeping of Tilapia Fillets as Sashimi

Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria(LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19(obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.

Characterization of Bacterial Communities Associating with Larval Development of Yesso Scallop(Patinopecten yessoensisis Jay, 1857) by High-Throughput Sequencing

Bacterial community presumably plays an essential role in inhibiting pathogen colonization and maintaining the health of scallop larvae, but limiting data are available for Yesso scallop （Patinopecten yessoensisis Jay, 1857） larval development stages. The aim of this study was to characterize and compare the bacterial communities associating with Yesso scallop larval development at fertilized egg S l, trochophora S2, D-shaped larvae S3, umbo larvae S4, and juvenile scallop S5 stages by Illumina high-throughput sequencing. Genomic DNA was extracted from the larvae and their associating baetera, and a gene segment covering V3-V4 region of 16S rRNA gene was amplified and sequenced using an Illumina Miseq sequencer. Overall, 106760 qualified sequences with an average length of 449 bp were obtained. Sequences were compared with those retrieved from 16S rRNA gene databases, and 4 phyla, 7 classes, 15 orders, 21 families, 31 genera were identified. Proteobacteria was predominant phylum, accounting for more than 99%, at all 5 larval development stages. At genus level, Pseudomonas was dominant at stages S1 （80.60%）, S2 （87.77%） and S5 （68.71%）, followed by Photobacterium （17.06%） and Aeromonas （1.64%） at stage S1, Serratia （6.94%）, Stenotrophomonas （3.08%） and Acinetobacter （1.2%） at stage S2, Shewanella （25.95%） and Pseudoalteromonas （4.57%） at stage S5. Moreover, genus Pseudoal- teromonas became dominant at stages S3 （44.85%） and S4 （56.02%）, followed by Photobacterium （29.82%）, Pseudomonas （11.86%）, Aliivibrio （8.60%） and Shewanella （3.39%） at stage S3, Pseudomonas （18.16%）, Aliivibrio （14.29%）, Shewanella （4.11%）, Psychro- monas （4.04%） and Psychrobacter （1.81%） at stage S4. From the results, we concluded that the bacterial community changed sig- nificantly at different development stages of Yesso Scallop larvae.

Isolation, identification and characterization of cadmium-resistant Pseudomonas aeruginosa strain E_1

Strain E1 with resistance to 18 mmol/L cadmium （Cd）, isolated from Cd-contaminated soil was identified by morphological observation, biochemical and physiological characterization and 16S rDNA sequence analysis. The resistance to heavy metals Cd, Cu, Co, Mn, Pb, Zn and 12 antibiotics was examined. The ability of removing Cd from solution was studied. The characterizations show that strain El is affiliated to Pseudomonas aeruginosa （P aeruginosa）. Strain E1 has high resistance to heavy metals and the order is found to be Cd〉Mn〉Zn〉Cu〉Pb〉Co in solid media. Strain E1 also exhibits the resistance to 12 antibiotics. Both living and non-living cells of strain E1 can remove Cd from solution, and living cell has better biosorption than non-living cell.

ROLE OF OUTER MEMBRANE PROTEINS IN IMIPENEM DIFFUSION IN PSEUDOMONAS AERUGINOSA

The present study identified the properties of porins in the outer membrane in Pseudomonas aeruginosa,and showed the role of outer membrane in determining imipenem diffusion in Pseudomonas aeruginosa The molecular weight of the major outer membrane protein was analyzed by SDS PAGE The purification of the porins in Pseudomonas aeruginosa was achieved by DEAE ion exchange HPLC The purified outer membrane proteins were reconstituted with phosphatidylcholine and dicetylphosphate into membrane vesicles, and were tested by the liposomes swelling method for the diffusion of imipenem The permeability assay showed that OprC (70 kD), OprD 2 (46kD), and OprE(43 kD) were the channel forming proteins But only OprD 2 was thought to be the likely route of imipenem diffusion

Antimicrobial Activity of Ulva reticulata and Its Endophytes

Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy （GC-MS） revealed the existence of phenol, 3, 5-bis （1, 1-dimethylethyl） in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas smtzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

Biodegradation of Petroleum Hydrocarbon by Pseudomonas Aeruginosa

A bacterial strain of the genus Pseudomonas aeruginosa was inoculated into a hydrocarbon culture medium and incubated for a definite period of time. The ability of the bacterial strain to biodegrade a hydrocarbon, viz. n-hexadecane, was evaluated through determining the hexadecane concentration in the inoculated culture medium on a gas chromatograph (GC). The effect of pH value on the degrading ability of the bacterial isolate and the impact of temperature on microbial growth were also explored. Test results showed that Pseudomonas aeruginosa was markedly effective in biodegrading n-hexadecane. Furthermore, the ability of Pseudomonas aeruginosa to biodegrade n-hexadecane was different at various pH values. Pseudomonas aeruginosa provided excellent degrading ability at a pH value of 7.0. The microbial cells of Pseudomonas aeruginosa increased with an increasing incubation duration at temperatures ranging from 28 ℃ to 35 ℃, and an exponential phase of microbial growth was observed.

Dolomite apatite separation by amphoteric collector in presence of bacteria

Bioflotation represents one of the growing trends to enhance the selectivity of conventional flotation processes. It utilizes the micro-organisms to replace or to interact with the chemical reagents to increase the gap between surface properties of similar minerals and to enhance the separation selectivity. In this work, dolomite-phosphate separation was investigated using amphoteric collector （dodecyl-N-carboxyethyl-N-hyroxyethyl-imidazoline） in presence of bacteria. Two types of bacteria, Corynebacterium- diphtheriae-intermedius （CDI）, and Pseudomonas aeruginosa （PA）, were used. The collector-bacteria interaction was characterized by Fourier transform infra-red （FTIR）, frothing height and Zeta potential. The results show that the collector-bacteria interaction improves the flotation selectivity. Although, the PA positively affects the separation results, the CDI cannot lower the MgO to less than 1%. A phosphate content of 0.7% MgO and 31.77% P205 with a recovery of 68% at pH 11, 3.0 kg/t amphoteric collector, 4× 10^7 cells of PA is obtained.

Optimizing rhamnolipid production by Pseudomonas aeruginosa ATCC 9027 grown on waste frying oil using response surface method and batch-fed fermentation

Rhamnolipid production by Pseudomonas aeruginosa ATCC 9027 with waste frying oil as sole carbon source was studied using response surface method. Cultures were incubated in shaking flask with temperature, NO3- and Mg2+ concentrations as the variables. Meanwhile, fed-batch fermentation experiments were conducted. The results show that the three variables are closely related to rhamnolipid production. The optimal cultivation conditions are of 6.4 g/L NaNO3 , 3.1 g/L MgSO4 at 32 ℃, with the maximum rhamnolipid production of 6.6 g/L. The results of fed-batch fermentation experiments show that feeding the oil in two batches can enhance rhamnolipid production. The best time interval is 72 h with the maximum rhamnolipid production of 8.5 g/L. The data are potentially useful for mass production of rhamnolipid on oil waste with this bacterium.

Allelopathic Effects of Eichhornia crassipes on the Growth of Microcystis aeruginosa

Algal blooms caused by eutrophication in fresh water are one of the major environmental problems in the world. Using biological methods to control algal growth, especially based on allelopathic inhibitory effects of aquatic macrophytes on phytoplankton growth, have been received world-wide attention. In this study, the allelopathic activity of the invasive macrophyte, Eichhornia crassipes （water hyacinth）, on blue-green algae, Microcystis aeruginosa （PCC7806） was investigated using coexistence assay. Our results showed that water hyacinth had disparate effects on the growth ofM~ aeruginosa （PCC7806） under different initial algal densities. Under lower initial algal density （OD650 = 0.10 and OD650 = 0.05）, the algal growth was significantly inhibited by water hyacinth （inhibition ratio was 95.6% and 97.3%, respectively）. While it was stimulated at higher initial algal densities （OD650 = 0.20）. Water hyacinth inhibited the growth of algae mainly through its root system. Culture water from water hyacinth and aqueous methanol extracts from dry roots samples also showed inhibition effects on algal growth. The inhibition effects increased as the increase of crude extract concentration, suggest that water hyacinth may excrete inhibitory substances from root system and show allelopathic inhibitory potential to the growth ofM. aeruginosa.

Optimization of Biosurfactant Production from Glycerol by Pseudomonas Aeruginosa EQ 109 Using Factorial Design 2^3

One possible application for the excess of glycerol, which is an exceeding byproduct in biodiesel industry, was used as carbon and energy sources for bioproducts synthesis. This work aims to evaluate biosurfactant production from glycerol by Pseudomonas aeruginosa EQ 109 isolated from crude oil-contaminated soil. Factorial design 2^3 was utilized to optimize the amount of biosurfactant produced, by using pH （A）, initial biomass concentration （B）, and initial glycerol concentration （C） as independent factors. The experiments were carried out in flasks containing 100 mL of mineral medium. Biosurfactant production was monitored by increase of the emulsification of aviation kerosene （E24） and surface tension reduction （STr）. The results have shown that, at pH = 7.0, in order to increase E24, variables as B and C are the most influential, leading to a maximum value of E24 = 79%, as well as for an increase of GC （GCmax = 49%）. STR was the variable with the best correlation factor for the proposed linear model （R2=0.96） and its maximum value was 48%. Xfwas not significant to the model, although it was influenced by pH and C, with C = 40g/L （Xfmax = 4.56 g/L）.

Antibacterial Effect of the Essential Oils Extracted From Ruta chalepensis L. and Ruta montana （L.） L.

Ruta genus is a member of the family Rutaceae that has been cultivated widely in many regions of the world because of its medicinal properties. In Tessala Mountain （Sidi Bel Abbes Country, North-Western of Algeria）, the Ruta genus commonly known by ＂fidjel＂ is represented by two species： Ruta Chalepensis L. and Ruta Montana （L.） L. frequently used by local population in a traditional treatment. The water-distilled essential oils from this species yielded 7.23% and 6.104% for Ruta chalepensis L. and Ruta montana （L.） L. respectively. The essential oil of Ruta montana （L.） L. showed a strong antibacterial activity against all bacterial strains tested （Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Mycobacterium kansasii ATCC ! 2478 and Mycobacterium vaccae ATCC 1548314） compared to Ruta chalepensis L. oils which have a moderate effect only on Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853. Therefor, the antibacterial properties of the essential oils of Ruta Chalepensis L. and Ruta Montana （L.） L. are now well established through this study and therefore could justify their future uses in the treatment of nosocomial infections.

Antimicrobial Activity of Stainless Steel with a Modified Tin Upperlayer on Meat Related Contaminants

Advanced material with antibacterial properties would be a promising way to improve the disinfection process in food plants. Our objective was to combine the bactericidal effect of TiO2 with the mechanical strength of TiN coatings. A TiO2 rutile film was obtained after annealing of a supplied 316 stainless steel with a TiN coating. This TiO2 upperlayer displays a photocatalytic activity under UV light exposure. The substrates with the TiN coating and the TiO2 upperlayer are more hydrophobic than the 316 control. The adhesion of either Listeria or Pseudomonas, on 316-TIN is characterized by the presence of clusters of cells, while the oxidation of the TiN surface leads to a more hydrophilic layer where cells are individualized. After UV illumination of the adherent cells and subsequent growth, the residual bacterial population present on 316-TIO2 is lower than that present on the 316-TIN. The bactericidal effect is more important on Listeria than on Pseudomonas.

Risk of Getting Nosocomial Water-Borne Infections from the Main Water Systems in Hospitals

Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.

Synthesis Antimicrobial Activity of p-Dimetyl-Amino-Benyzlaldehide Shift Base of α-NaftyI-Amine and Metal Complexes

A new Shift bases was synthesized by the reaction of p-dimetyl-amino-benzylaldehide and α-naftyl-amine. All synthesized compounds were characterized by elemental analysis, IR （infra red） spectroscopy and NMR （nuclear magnetic resonance） spectroscopy and evaluated for their in vitro antifungal activities of the compounds tested against Pseudomonas aeruginosa, Mycobacterium lacticolium, Aspergillus niger, Cladasporium resinale, Penicillium chrosegenum, Chastorniurn gloloodium and Trichoderma virideh. These derivatives have vast range of biological activities which benefit us.

Production and Recovery of Rhamnolipids Using Sugar Cane Molasses as Carbon Source

Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration ratio （Vm/Vf） of 0.4 and 0.6. A concentration of 3.0% was used for the carbon and energy source （molasses） and of 0.3% for the nitrogen source （NaNO3）. Samples were removed at regular times until 96 hours of cultivation. The reduction in surface tension was measured using the ring method; cell concentration was obtained by the dry mass and substrate consumption by the DNS method. The metabolite produced was extracted and quantified by the thioglycolic method. The results showed a maximum surface tension reduction of 46.57% after 60 h, 3.63 g/L of biomass after 8 h （μXmax =0.15 h^-1）, 79.60% of substrate consumption （μs= 0.67 h-1） and 4.47 g/L of rhamnolipid （μp=0.029 h^-1）.

Aquatic Toxicities of Three Aryloxyphenoxypropanoic Acid Herbicides on Cyanobacterium Microcystis aeruginosa

Pesticides will be released into aquatic systems after application in agriculture or industry. AOPPs （aryloxyphenoxypropanoic acids） herbicides, including fenoxaprop, quizalofop-P-ethyl and haloxyfop-methyl, can pose aquatic toxicity on cyanobacterium M. aeruginosa （Microcystis aeruginosa）. The inhibition percentages of the biomass of M. aeruginosa exposure to 10 mg＇L-I fenoxaprop, quizalofop-P-ethyl and haloxyfop-methyl on day 7 were 23.13%, 7.55%, and 7.56%, respectively. Protein content was also inhibited by the three AOPPs to fenoxaprop is the most toxic, followed by quizalofop-P-ethyl varying degrees. The growth and protein content results showed that and haloxyfop-methyl. It indicates that both the biomass and the protein content can be served as an indicator for evaluating the toxicity of the three chemicals. Growth rates of M. aeruginosa exposure to fenoxaprop are also the most significantly different compared to the control, which means that fenoxaprop is the most toxic among the three compounds. Results from this study may provide insights for evaluation of environmental risks of AOPPs. In addition, such insights will be helpful for guiding the application of AOPPs in agriculture.

Biosurfactant Production by Pseudomonas aeruginosa and Yarrowia lipolytica and Its Use for Detergent Formulations

This work reports detergents production using biological surfactants, microbiologically synthesized, and compares its foaming power and emulsification capacity to those presented by a petroleum based surfactant. Both used microorganisms were capable to produce surfactants, been able to emulsify oil/water mixtures and cause decrease of surface tension of water. The biosurfactant produced from Yarrowia lipolytica has a critical micelle concentration lower than that obtained from Pseudomonas aeruginosa （10 and 30 mg·Lt, respectively）, but the later showed better results in foaming power and emulsification experiments, similar to the synthetic detergent.

Antibacterial Effect of Lavender （Lavandula） Flavor （Volatile）

The objective of this study was to test the essential oil-emitted flavor （volatile） of lavender by bacteria killing potency using Escherichia coli, methicillin-resistant Staphylococcus aureus （MRSA）, enterohemorrhagic E. coli O157：H7, Pseudomonas aeruginosa and Candida albicans. Antibacterial activity was assessed by creating of the bacterial growth curve in the liquid medium cultivation and the growth inhibition on the agar plate cultivation. Citronellal, one of compounds in Rosa rugose oil, was used as a positive control for comparison in activity. The results showed that lavender and citronellal flavor （volatile） or oil respectively demonstrated bacteria killing effect in both analytical manners. However, P. aeruginosa resisted bacteria killing potency of lavender （citronellal） oil or oil-emitted flavor. It could be concluded that both lavender oil-emitted flavor and oil showed bacteria killing potency. Lavender oil （or oil-emitted flavor） will be expected to apply for the patient waiting room to disinfect in air along with the mental relaxation of the patient.

KL-0153, a novel inhibitor of Pseudomonas aeruginosa MexAB-OprM efflux pump

Pseudomonas aeruginosa is an opportunistic pathogen that contributes to high morbidity and mortality. MexAB-OprM is the main efflux pump among the Resistance-Nodulation-Division family multi-drug effiux systems, which contribute greatly to the multidrug resistance of P. aeruginosa. Effiux pump inhibitors （EPIs） of MexAB-OprM could enhance the activity of the antibiotics effiuxed by MexAB-OprM, and thus they might be useful in the clinic as antibacterial synergistic agents. In this work, a new EPI of MexAB-OprM, KL-0153, was discovered by screening of a small molecular library. Its inhibition of MexAB-OprM was confirmed by assays of synergistic activity and EB accumulation. The activity of KL-0153 was shown to be synergistic with antibiotics effiuxed by MexAB-OprM when they were tested against strains expressing MexAB-OprM, especially so for the strains that express MexAB-OprM at high levels. KL-0153 showed more activity than the positive drug carbonyl cyanide m-chlorophenylhydrazone in the EB accumulation assay. It cannot be neglected that KL-0153 has significant liver and kidney toxicity. However, KL-0153 may be a lead comoound for the research and development of new tvoes of EPIs.