Description: To screen potential nematophagous fungi candidates for the biological control of parasitic nematodes in livestock, in vitro and in vivo studies of the native isolates of nematophagous fungi against the larvae of trichostrongylides were conducted. The in vitro predatory activity of 16 native nematophagous fungal isolates on the larvae of trichostrongylides in sheep feces was assessed. In the ten isolates of Duddingtonia flagrans , the reduction percentage for the infective larvae (L3) of Trichostrongylus colubriformis ranged from 57.21 to 99.83%, and that of Haemonchus contortus ranged from 62.12 to 99.88%. The analysis of the same assay on five isolates of Arthrobotrys superba and one isolate of A. cookedickinson ( Monacrosporium cystosporum ) showed comparable results with those for D. flagrans . To determine the excretion time of fungal isolates in feces after oral administration, D. flagrans (SDH035) were studied in vivo in sheep and rabbits. Results showed that the tested fungal isolates existed in sheep feces from 12 to 72 h after fungal treatment, and the fungal excretion in rabbit feces occurred at 4 h, reached a peak at 10 h, and declined gradually 18 h after oral administration. All the native fungal isolates were assessed after passing through the gastrointestinal tract of sheep. Treatment with isolates of D. flagrans significantly reduced the number of developing larvae in the feces, and the efficacies ranged from 55.15 to 98.82%. One out of the five isolates of A. superba and A. cookedickins on (BS002) survived after passing through the gastrointestinal tract, and the L3 reduction rates were 83.79 and 81.33%, respectively. Results of the present study provide information about the in vitro predatory activity of nematophagous fungi from China on the L3 of trichostrongylides and their ability to pass through the gastrointestinal tract before administering them for biocontrol.

Description: Riboflavin (vitamin B 2 ) is one of the B-group water-soluble vitamins and is essential for energy metabolism of the cell. The aim of this study was to determine factors that affect riboflavin production by Lactobacillus ( L .) plantarum CRL 725 grown in a semi defined medium and evaluate the expression of its rib genes. The factors found to enhance riboflavin production in this medium were incubation at 30 °C, and the addition of specific medium constituents, such as casamino acids (10 g L −1 ), guanosine (0.04 g L −1 ), and sucrose as carbon source (20 g L −1 ). In these conditions, higher riboflavin concentrations were directly associated with significant increases in the expression of ribA , ribB , and ribC genes. The culture conditions defined in this work and its application to a roseoflavin resistant mutant of L. plantarum allowed for a sixfold increase in riboflavin concentrations in our semi-defined medium which were also significantly higher than those obtained previously using the same strain to ferment soymilk. These conditions should thus be evaluated to increase vitamin production in fermented foods.

Description: In this study, we analyzed the in vivo microbial community structure and diversity differences of Haemaphysalis flava ( H. flava ) in four developmental stages (egg, larva, nymph, and adult) to determine which bacterial genera could be propagated through transovarial transmission and transmitted by transstadial transmission during different developmental stages of H. flava . Paired-end sequencing of the V3 region of the 16S ribosomal DNA (16S rDNA) of H. flava in four developmental stage samples was conducted using the Illumina MiSeq sequencing platform. The following operational taxonomic units (OTUs) of H. flava were obtained during the four developmental stages: 89 of egg, 111 of larva, 104 of nymph, and 106 of female adult tick. Sixty-four of these OTUs had high similarity in the four developmental stages of H. flava . Eight bacterial genera had the highest abundances in all developmental stages, namely, Rickettsia , Coxiella , Pseudomonas , Ehrlichia , Escherichia , Acinetobacter , Citrobacter , and Cupriavidus . The nymph had the highest abundance of Coxiella , and the female adult tick had the highest abundance of Rickettsia . Staphylococcus and Wolbachia were detected in all developmental stages except the egg.

Description: Mercury resistant (Hg R ) bacteria were screened from industrial effluents and effluents-polluted rhizosphere soils near to districts Kasur and Sheikhupura, Pakistan. Out of 60 isolates, three bacterial strains, Bacillus sp. AZ-1, Bacillus cereus AZ-2, and Enterobacter cloacae AZ-3 showed Hg-resistance as 20 μg ml −1 of HgCl 2 and indole-3-acetic acid (IAA) production as 8–38 μg ml −1 . Biochemical and molecular characterization of selected bacteria was confirmed by 16S ribotyping. Mercury resistant genes mer A, mer B, and mer E of mer operon in Bacillus spp. were checked by PCR amplification. The mer E gene involved in the transportation of elemental mercury (Hg 0 ) via cell membrane was first time cloned into pHLV vector and transformed in C43(DE3) Escherichia coli cells. The recombinant plasmid (pHLMerE) was expressed and purified by nickel (Ni +2 ) affinity chromatography. Chromatographic techniques viz. thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and Gas chromatography–mass spectrometry (GC–MS) confirmed the presence of Indole-3-acetic acid (IAA) in supernatant of selected bacteria. The strain E. cloacae AZ-3 detoxified 88% of mercury (Hg +2 ) from industrial effluent ( p  〈 0.05) after immobilization in Na-alginate beads. Finally, Hg-resistant and IAA producing bacterial consortium of two strains, Bacillus sp. AZ-1 and E. cloacae AZ-3, inoculated in mercury amended soil with 20 μg ml −1 HgCl 2 resulted 80, 22, 64, 116, 50, 75, 30, and 100% increase as compared to control plants in seed germination, shoot and root length, shoot and root fresh weight, number of pods per plant, number of seeds and weight of seeds, respectively, of chickpea ( Cicer arietinum L.) in pot experiments ( p  〈 0.05).

Description: Cover illustration: Growth of Pestalotiopsis microspora on complete medium. The fungi were incubated at 28 °C for 96 h. (Photo: Qian Zhang, State Key Program of Microbiology and Department of Microbiology, College of Life Sciences, Nankai Universit, P.R. China)

Description: Rhodobacter sphaeroides is a purple non-sulfur bacterium which photoheterotrophically produces hydrogen from organic acids under anaerobic conditions. A gene coding for putative chlorophyll a synthase (chlG) from cyanobacterium Prochlorococcus marinus was amplified by nested polymerase chain reaction and cloned into an inducible-expression plasmid which was subsequently transferred to R. sphaeroides for heterologous expression. Induced expression of chlG in R. sphaeroides led to changes in light absorption spectrum within 400–700 nm. The hydrogen production capacity of the mutant strain was evaluated on hydrogen production medium with 15 mM malate and 2 mM glutamate. Hydrogen yield and productivity were increased by 13.6 and 22.6%, respectively, compared to the wild type strain. The results demonstrated the feasibility of genetic engineering to combine chlorophyll and bacteriochlorophyll biosynthetic pathways which utilize common intermediates. Heterologous expression of key enzymes from biosynthetic pathways of various pigments is proposed here as a general strategy to improve absorption spectra and yield of photosynthesis and hydrogen gas production in bacteria.

Description: Nitrospira are the most widespread and well known nitrite-oxidizing bacteria (NOB) and putatively key nitrite-oxidizers in acidic ecosystems. Nevertheless, their ecology in agriculture soils has not been well studied. To understand the impact of straw incorporation on soil Nitrospira -like bacterial community, a cloned library analysis of the nitrite oxidoreductase gene- nxrB was performed for a long-term rapeseed-rice rotation system. In this study, most members of the Nitrospira -like NOB in the paddy soils from the Wuxue field experiment station were phylogenetically related with Nitrospira lineages II. The Shannon diversity index possessed a decrease trend in the straw applied soils. The relative abundances of 16 OTUs (accounting 72% of the total OTUs, including 11 unique OTUs and 5 shared OTUs) were different between in the straw applied and control soils. These data suggested a selection effect from the long-term straw fertilization. Canonical correspondence analysis data showed that a centralized group of Nitrospira -like NOB OTUs in the community was partly explained by the soil ammonium, nitrate, available phosphorus, and the available potassium. This could suggest that straw fertilization led to the soil Nitrospira -like NOB community shift, which was correlated with the change of available nutrients in the bulk soil.

Description: Benzo[ a ]pyrene, a high molecular weight polycyclic aromatic hydrocarbon possesses carcinogenic, teratogenic, and mutagenic properties. The present study focuses on benzo[ a ]pyrene degradation by Pleurotus ostreatus PO-3, characterization and identification of metabolites produced and the extent of degradation in the presence of axenic culture of P. ostreatus PO-3 and defined co-cultures of the basidiomycete with bacteria and non-basidiomycete fungi. Thin-layer chromatography revealed that P. ostreatus PO-3 transformed benzo[ a ]pyrene to polar metabolites. Following degradation, appearance of numerous peaks in the mass spectrum indicated that benzo[ a ]pyrene degradation was a result of the metabolic activity of P. ostreatus PO-3. A degradation product corresponding to the m/z 284.2 was detected which could possibly be B a P-quinone, resulting from the oxidation of benzo[ a ]pyrene. Compared to the axenic culture of P. ostreatus PO-3 (64.3%), co-cultures of P. ostreatus PO-3 and Penicillium chrysogenum MTCC 787 and P. ostreatus PO-3 and Pseudomonas aeruginosa MTCC 1688 could degrade 86.1 and 75.1% of benzo[ a ]pyrene, respectively. Thus it could be inferred from the present investigation that the combined catabolic activities of P. ostreatus PO-3 with bacteria and non-basidiomycete fungi can produce synergistic effects to enhance B a P degradation. The increase in the generation of polar metabolites as degradation products from the recalcitrant parent compound advocates the potential application of P. ostreatus PO-3 in benzo[ a ]pyrene bioremediation.

Description: Green synthesized nanoparticles have gained great attention due to their non-toxic and non-hazardous nature. In the present study, bark extract of the medicinal plant in Ayurveda Crataeva nurvala (Buch–Ham) (CN) was chosen for the biosynthesis of silver nanoparticles (AgNPs). These NPs were characterized by Ultra violet visible spectroscopy, Fourier Transform Infra Red, Atomic Force Microscopy, and Transmission Electron Microscopy (TEM). The average particle size of green synthesized CN-AgNPs was 15.2 ± 1.01 nm. Gas chromatography- mass spectrometry analysis of methanolic bark extract involved in the formation of CN-AgNPs revealed lupeol as a major active component. In this study, CN-AgNPs (15 μg ml −1 ) efficiently suppressed the production of quorum sensing mediated virulence factors viz. pyocyanin, protease, hemolysin, and biofilm formation in Pseudomonas aeruginosa . The pyocyanin production was strongly inhibited (74.64%) followed by proteolysis (47.3%) and hemolysin production (47.7%). However, the biofilm forming ability was maximally reduced up to 79.70%. Moreover, the Confocal Laser Scanning Microscopic Analysis showed that CN-AgNPs inhibit colonization of P. aeruginosa on to the surface. Furthermore, TEM analysis revealed internalization of CN-AgNPs inside the bacterial cell. It is concluded that green synthesized AgNPs have great potential to inhibit virulence factors and biofilm forming ability of drug-resistant clinical isolates of P . aeruginosa .