Vibrio cholerae strains possess multiple strategies for abiotic and biotic surface colonization

Despite its notoriety as a human pathogen, Vibrio cholerae is an aquatic microbe suited to live in freshwater, estuarine, and marine environments where biofilm formation may provide a selective advantage. Here we report characterization of biofilms formed on abiotic and biotic surfaces by two non-O1/O139 V. cholerae strains, TP and SIO, and by the O1 V. cholerae strain N16961 in addition to the isolation of 44 transposon mutants of SIO and TP impaired in biofilm formation. During the course of characterizing the mutants, 30 loci which have not previously been associated with V. cholerae biofilms were identified. These loci code for proteins which perform a wide variety of functions, including amino acid metabolism, ion transport, and gene regulation. Also, when the plankton colonization abilities of strains N16961, SIO, and TP were examined, each strain showed increased colonization of dead plankton compared with colonization of live plankton (the dinoflagellate Lingulodinium polyedrum and the copepod Tigriopus californicus). Surprisingly, most of the biofilm mutants were not impaired in plankton colonization. Only mutants impaired in motility or chemotaxis showed reduced colonization. These results indicate the presence of both conserved and variable genes which influence the surface colonization properties of different V. cholerae subspecies.     

Effect of nutrition on growth and virulence of the entomopathogenic fungus Beauveria bassiana

Three isolates of the entomopathogen Beauveria bassiana along with one strain of Metarhizium anisopliae were cultured on seven media with different carbon/nitrogen (C/N) ratios. The effect of nutrition on virulence of the isolates was evaluated via measurement of colony growth, spore yield, germination speed, conidial C/N ratio and Pr1 (a serine protease) activity. 'Osmotic stress' medium produced the lowest colony growth with low numbers of conidia in all isolates. However, these conidia showed a high germination rate and virulence. However, conidial Pr1 activity was low in some isolates. In most but not in all cases conidia from 1% yeast extract, 2% peptone and low (10 : 1) C/N medium had higher Pr1 activity compared with conidia from other media. However, in some instances we could not conclude that there was a relationship among germination rate, conidial Pr1 activity and virulence. C/N ratio of conidia was statistically different among various media and fungal isolates. Conidia with lower C/N ratio generally produced lower LT(50) (lowest median lethal time) values (more virulent). Insect-passaged conidia from different media had lower C/N ratio compared with similar conidia from artificial cultures. Therefore, they should be more virulent than in vitro produced conidia. As germination rate, conidial Pr1 activity and C/N ratio are independent of host, it seems that host-related determinants such as insect cuticle and physiology and environmental conditions may influence host susceptibility and therefore fungal isolate virulence towards host insects.     

Halotolerant Plant Growth-Promoting Rhizobacteria Induce Salinity Tolerance in Wheat by Enhancing the Expression of SOS Genes

Journal of Plant Growth Regulation - Soil salinity is one of the main yield-limiting factors in various crops. Under different environmental stresses, many rhizobacteria have demonstrated...     

Comparative study on floristic diversity of protected and unprotected Forests of Sathan Gali,District Mansehra,KP, Pakistan

This first ever study was carried out to explore the floristic composition of protected and unprotected forests of Sathan Gali, District Mansehra, KP, Pakistan. The study area being the part of the Western Himalayas harbours rich floristic diversity. In the current investigation, an effort was made to record primary data about floral diversity of the area. The study area was visited recurrently during 2013 and 2014. Plants were collected from different sampling sites, identified, preserved and deposited in Herbarium of Hazara University, Mansehra. A total of 127 plants species including 59 common and 68 different were found in 13 stands of reserved forest. The different species were only confined with this forest whereas common plant species were distributed in both forests. The dominant family was Asteraceae (13 species, 10.7%) followed by Labiateae (10 species, 7.75%), Poaceae and Rosaceae (8 species, 6.2%) each, Polygonaceae and Pteridaceae by (5 species, 3.87%) each. Angiosperms were represented by 118 (92.91%), plant species, Pteridophytes 5(3.93%) species and Gymnosperms 4 (3.14%) species were recorded in reserved forest. Only single species of climber was documented. The number of herbs, shrubs and trees species recorded were 73.64%, 13.17% and 10.07% respectively. A total of 103 plant species of 55 families including 61 common in both forest types and 42 species different to guzara Forest. These plant species were recorded from 22 sampling stands. Angiosperms by (92.3%) plant species, Gymnosperms (2.88%) and Pteridophytes (4.8%) were recorded. The dominant family was Poaceae by 11 plant species followed by Asteraceae and Rosaceae each represented by 10 species and Pteridaceae by 5 plant species. Habit wise 69.23% were herbs, 14.42% shrubs and 16.34% species of tree were reported. This study will assist ecologists, botanists, taxonomist, conservationists and policy makers to mend, and manage the current vegetation status and sustainability for upcoming generations. The present investigation will also serves as base line for future researches on the Himalaya regions.     

Neuroprotective role of BNIP3 under oxidative stress through autophagy in neuroblastoma cells

Reactive oxygen species (ROS) are produced due to oxidative stress which has wide range of affiliation with different diseases including cancer, heart failure, diabetes and neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease, ischemic and hemorrhagic diseases. This study shows the involvement of BNIP3 in the amplification of metabolic pathways related to cellular quality control and cellular self defence mechanism in the form of autophagy. We used conventional methods to induce autophagy by treating the cells with H₂O₂. MTT assay was performed to observe the cellular viability in stressed condition. MDC staining was carried out for detection of autophagosomes formation which confirmed the autophagy. Furthermore, expression of BNIP3 was validated by western blot analysis with LC3 antibody. From these results it is clear that BNIP3 plays a key role in defence mechanism by removing the misfolded proteins through autophagy. These results enhance the practical application of BNIP3 in neuroblastoma cells and are helpful in reducing the chances of neurodegenerative diseases. Although, the exact mode of action is still unknown but these findings unveil a molecular mechanism for the role of autophagy in cell death and provide insight into complex relationship between ROS and non-apoptotic programmed cell death.     

Sterile Immunity to Malaria after DNA Prime/Adenovirus Boost Immunization Is Associated with Effector Memory CD8+T Cells Targeting AMA1 Class I Epitopes

Background

Fifteen volunteers were immunized with three doses of plasmid DNA encoding P. falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1) and boosted with human adenovirus-5 (Ad) expressing the same antigens (DNA/Ad). Four volunteers (27%) demonstrated sterile immunity to controlled human malaria infection and, overall, protection was statistically significantly associated with ELISpot and CD8+ T cell IFN-γ activities to AMA1 but not CSP. DNA priming was required for protection, as 18 additional subjects immunized with Ad alone (AdCA) did not develop sterile protection.

Methodology/Principal Findings

We sought to identify correlates of protection, recognizing that DNA-priming may induce different responses than AdCA alone. Among protected volunteers, two and three had higher ELISpot and CD8+ T cell IFN-γ responses to CSP and AMA1, respectively, than non-protected volunteers. Unexpectedly, non-protected volunteers in the AdCA trial showed ELISpot and CD8+ T cell IFN-γ responses to AMA1 equal to or higher than the protected volunteers. T cell functionality assessed by intracellular cytokine staining for IFN-γ, TNF-α and IL-2 likewise did not distinguish protected from non-protected volunteers across both trials. However, three of the four protected volunteers showed higher effector to central memory CD8+ T cell ratios to AMA1, and one of these to CSP, than non-protected volunteers for both antigens. These responses were focused on discrete regions of CSP and AMA1. Class I epitopes restricted by A*03 or B*58 supertypes within these regions of AMA1 strongly recalled responses in three of four protected volunteers. We hypothesize that vaccine-induced effector memory CD8+ T cells recognizing a single class I epitope can confer sterile immunity to P. falciparum in humans.

Conclusions/Significance

We suggest that better understanding of which epitopes within malaria antigens can confer sterile immunity and design of vaccine approaches that elicit responses to these epitopes will increase the potency of next generation gene-based vaccines.     

Structure of the neural (N-) cadherin prodomain reveals a cadherin extracellular domain-like fold without adhesive characteristics

Classical cadherins mediate cell-cell adhesion through calcium-dependent homophilic interactions and are activated through cleavage of a prosequence in the late Golgi. We present here the first three-dimensional structure of a classical cadherin prosequence, solved by NMR. The prototypic prosequence of N-cadherin consists of an Ig-like domain and an unstructured C-terminal region. The folded part of the prosequence-termed prodomain-has a striking structural resemblance to cadherin "adhesive" domains that could not have been predicted from the amino acid sequence due to low sequence similarities. Our detailed structural and evolutionary analysis revealed that prodomains are distant relatives of cadherin "adhesive" domains but lack all the features known to be important for cadherin-cadherin interactions. The presence of an additional "nonadhesive" domain seems to make it impossible to engage homophilic interactions between cadherins that are necessary to activate adhesion, thus explaining the inactive state of prodomain-bearing cadherins.