Exclusion of Vibrio spp. by an antagonistic marine actinomycete Streptomyces rubrolavendulae M56

A marine actinomycete Streptomyces rubrolavendulae M56 isolated from the sediments of Bay of Bengal and displaying biogranulation property was used for the study. The strain showed antagonistic property against vibrios, the opportunistic pathogens in aquaculture. The efficacy of the biogranules of actinomycete M56 in competitive exclusion of Vibrio spp. was tested both in vitro and in vivo. Streptomyces rubrolavendulae M56 biogranules could significantly exclude the pathogenic Vibrio spp. in co‐culture experiments (in vitro). In vivo exclusion of Vibrio spp. in a Penaeus monodon postlarval rearing system was evaluated by treatment of the rearing water with biogranules of S. rubrolavendulae M56. The experiments proved that S. rubrolavendulae M56 biogranules could reduce the pathogenic Vibrio spp., while maintaining total heterotrophic bacterial count. Therefore, the actinomycete biogranules (M56) can be used as a promising alternative to antibiotics in the shrimp larval production system which is often affected by vibriosis.     

Fungal endophyte infection increases carbon sequestration potential of southeastern USA tall fescue stands

Tall fescue (Schedonorus arundinaceous (Schreb.)) is often infected with a common toxic fungal endophyte (Neotyphodium coenophialum) capable of producing alkaloids that affect grazing animal health, insect herbivory, plant production, and litter decomposition. The strength of these endophyte-associated effects is thought to depend on the abiotic and biotic conditions of a specific site. Prior work from Georgia, USA, has demonstrated that fungal endophyte infection can increase soil carbon pools of tall fescue pastures; however, for endophyte infection to contribute substantially to regional carbon sequestration, this result would have to hold true across the broad range of environmental conditions that support tall fescue growth. In this study, we evaluated whether endophyte infection consistently alters various soil parameters, including carbon storage, of tall fescue stands located throughout the southeastern United States. Soil samples were collected from nine sites with established paired high- and low- endophyte-infected tall fescue stands. These samples were analyzed for basic soil parameters, soil organic carbon (SOC), soil total nitrogen (TN), particulate and non-particulate organic matter-C and -N (POM, n-POM), C and N mineralization rates, and microbial biomass and community composition. Averaged across all sites, endophyte-infected tall fescue stands had 6% greater SOC and 5% greater TN pools in surface soil than adjacent endophyte-free stands. The lack of a significant interaction between site and endophyte infection status indicated that this result was relatively consistent across sites, despite differences in stand age, climate, and other environmental conditions. While POM C and POM N tended to be higher in endophyte-infected than endophyte-free stands, this result was not significant. However, greater pools of n-POM C and N were observed in endophyte-infected vs. endophyte-free stands when averaged across all the sites, suggesting increased retention of recalcitrant substrates occurred in response to fungal endophyte infection. Total microbial biomass, measured via phospholipid fatty acid (PLFA) analysis, was greater in endophyte-infected than endophyte-free soils when averaged across sites, reflecting the trends observed with SOC and TN. Microbial community composition shifted somewhat in response to fungal endophyte infection: significantly higher fungal to bacterial ratios were observed in endophyte-free compared to endophyte-infected stands. However, ordinations of the PLFA data demonstrated only slight separation of endophyte-infected and endophyte-free microbial communities at some sites and no clear separation at others. Enhanced SOC, TN, recalcitrant n-POM C and N pools, and altered microbial biomass and communities suggest that this aboveground fungal endophyte symbiosis has widespread effects on soil biology and biochemistry, and that high prevalence of the aboveground endophyte increases C sequestration capacity of tall fescue stands throughout the southeastern USA.     

A climatic risk analysis of the threat posed by the South American leaf blight (SALB) pathogen <Emphasis Type="Italic">Microcyclus ulei</Emphasis> to major rubber producing countries

In 2010, symptoms of cobweb disease were observed on cultivated Pleurotus eryngii crops in Spain. Based on morphological and genetic analyses, the causal agent of cobweb was identified as Cladobotryum mycophilum. Pathogenicity tests on fruit bodies were performed using conidial suspensions of three C. mycophilum isolates. The causal agent was re-isolated in 80–85 % of the fruit bodies inoculated internally and 15–40 % of those fruit bodies inoculated on the cap surface. The results pointed to a certain resistance of the P. eryngii cap surface to the mycelium of C. mycophilum. Two cropping trials inoculated with C. mycophilum were set up to evaluate the pathogenicity of the causal agent of cobweb in two casings. At the end of the growth cycle, 50–60 % of the inoculated blocks cased with mineral soil, and 20–33 % of the inoculated blocks cased with black peat showed cobweb symptoms. This difference in the appearance of the disease and its aggressiveness may be partly explained by different electrical conductivity values of the casing materials used. In vitro sensitivity of the C. mycophilum isolates and P. eryngii strains against four fungicides (chlorothalonil, prochloraz-Mn, thiabendazole and thiophanate-methyl) was assessed in radial growth experiments on fungicide-amended media. The most effective fungicides for inhibiting the in vitro growth of C. mycophilum were prochloraz-Mn and chlorothalonil, while prochloraz-Mn was also the most selective fungicide between P. eryngii and C. mycophilum, and chlorothalonil was the most toxic fungicide against the P. eryngii mycelium.     

Association with the Syndrome "Basses Richesses" of Sugar Beet of a Phytoplasma and a Bacterium-Like Organism Transmitted by a Pentastiridius sp

ABSTRACT The syndrome "basses richesses" of sugar beet (SBR) was first observed in 1991 in Burgundy, France. A cixiid planthopper, Pentastiridius beieri, has been proved to be involved in the transmission to sugar beet of a stolbur phytoplasma, which could be detected in some affected plants. In 2000, periwinkle and sugar beet exposed to field-collected cixiids developed symptoms similar to SBR on sugar beet. Use of 4'-6-diamidino-2-phenylindole (DAPI) staining and transmission electron microscopy confirmed the presence of phytoplasma in some of the plants, which were also positive for this pathogen in a polymerase chain reaction (PCR) analysis. A phloem-restricted gram-negative bacteria was seen in all other plants with symptoms but PCR-negative for phytoplasma. Three primer pairs reported as diagnostic for phloem-limited bacteria were tested but only primers specific for 'Candidatus Phlomobacter fragariae' gave a positive signal, which related to the presence of DAPI-stained bacteria-like objects in diseased plants. Although phytoplasma and bacterium-like organisms were associated with the same macroscopic symptoms on sugar beet, histochemical analysis of phloem cells showed that phytoplasma were associated with cell necrosis and cell wall lignification, while bacteria were associated with these same abnormalities as well as deposit of phenolic compounds in the lumen of phloem cells.     

Retrospective analysis of the influence of environmental drivers on commercial stocks and fishing opportunities in the Irish Sea

Irish Sea fisheries have undergone considerable change in recent years following the decline of commercially important finfish stocks and their slow response to management's recovery plans. In 2015, the fishing industry called for a holistic exploration into the impact of environmental change and food web effects to identify the drivers underpinning stock dynamics. In this study, we identify correlations between large‐scale climatic indicators, temperature, primary and secondary productivity, and fish recruitment in the Irish Sea and incorporate them into an Ecopath with Ecosim food web model co‐created by scientists and fishers. Negative correlations were found between the North Atlantic Oscillation winter index (NAOw) and large zooplankton abundance and between the Atlantic Multidecadal Oscillation (AMO) and the recruitment of cod (Gadus morhua) and whiting (Merlangius merlangus). Using correlation analyses to direct the addition of environmental drivers to the Irish Sea ecosystem model improved the models fit against observed biomass and catch data and revealed the indirect impacts of environmental change as mitigated through trophic interactions. Model simulations suggest that historic environmental change suppressed the overall production of commercial finfish, limiting opportunities for the fishing industry, whilst also dampening the rate of stock recovery despite marked reductions in fishing effort. These results suggest that failure to account for ecosystem information may lead to misconceived expectations and flawed fisheries management; therefore, there is a need to operationalize ecosystem information through management procedures to support fisheries advice.     

Molecular Docking of Laccase Protein from Bacillus Safensis DSKK5 Isolated from Earthworm gut: A Novel Method to Study dye Decolorization Potential

Water, Air, &; Soil Pollution - The bacterial communities in the intestinal tracts of earthworm were isolated by culture-dependent approaches. In total, 72 cultures were isolated and purified...     

Antimicrobial flavonoids from the stem bark of Erythrina burttii

The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant.     

A study of water distribution from a branch to distributary canals: A case study of Gugera Branch,Punjab, Pakistan

This study was conducted on Gugera Branch of Lower Chenab Canal, Punjab, Pakistan. Sample distributaries off taking from Gugera Branch were selected for the study. The existing conditions of water distribution among the distributaries were studied. Field data were collected during the whole of 1988. Field observations suggested that the variability at the head of distributaries is much greater than the variability in the Gugera Branch under existing operational practices. The distribution of water among the distributaries is rarely in accordance with design criteria. Some channels get priority over other channels. The annual closure period varied from 17 to 41 days for different channels. The discharge at the head of distributaries remained lower than the standard operational range for 69 to 183 days in a year. The data suggested that a regulating gate at the head of the distributary can reduce discharge variation up to 2.4 times compared with a Karrees System (wooden stop logs used for water regulation). The data indicated that the adjustments in the head gate of a distributary on daily basis can substantially improve discharge conditions at the head of distributary. Rotational schedules are not being followed as per design and need to be improved. Most of the existing head discharge relationships of discharge measuring structures are not reliable. A frequent calibration of these structures is recommended.