Himalayan bacterial endophytes enhance microalgal cell numbers and chlorophyll content in synthetic co-culture

Endophytic bacteria associated with medicinal plants from Himalayan mountains possess great biotechnological potential. However, the influence of these Himalayan bacterial endophytes (HBE) on microalgal-promotion and metabolite production is still largely unknown. In this study, the interactions between two endophytic bacterial isolates of an endangered Himalayan medicinal plant and long-chain fatty acids accumulating green alga Micractinium sp. GA001 are characterized in synthetic co-culture systems. The endophytes Staphylococcus pasteuri PPE11 and Yersinia enterocolitica PPE118 significantly enhance microalgal cell numbers with 56% and 49% increase in total chlorophyll content, respectively. Co-culturing microalgae with these endophytes demonstrated distinct responses toward photosynthesis at different temperatures. Endophytes were metabolically active for an extended time (more than 28 days) in co-culturing. The findings were further complemented with genomics studies of endophytes which were subjected to multiple sequencing approaches to assemble and annotate their genomes, resulting in key genes involved in PGP activities, metabolites production and transportation being identified. This study expands the benefits and bioprocessing potential of endophytes of Himalayan medicinal plants.

     

Dietary Lactobacillus acidophilus and Mannan-Oligosaccharides Alter the Lipid Metabolism and Health Indices in Broiler Chickens

Probiotics and Antimicrobial Proteins - The effects of dietary Lactobacillus acidophilus (LBA) and mannan-oligosaccharide (MOS) supplementation on lipid metabolism and consequent lipid profile and...     

Hydrolysis of aromatic β-glucosides by non-pathogenic bacteria confers a chemical weapon against predators

Bacteria present in natural environments such as soil have evolved multiple strategies to escape predation. We report that natural isolates of Enterobacteriaceae that actively hydrolyze plant-derived aromatic β-glucosides such as salicin, arbutin and esculin, are able to avoid predation by the bacteriovorous amoeba Dictyostelium discoideum and nematodes of multiple genera belonging to the family Rhabditidae. This advantage can be observed under laboratory culture conditions as well as in the soil environment. The aglycone moiety released by the hydrolysis of β-glucosides is toxic to predators and acts via the dopaminergic receptor Dop-1 in the case of Caenorhabditis elegans. While soil isolates of nematodes belonging to the family Rhabditidae are repelled by the aglycone, laboratory strains and natural isolates of Caenorhabditis sp. are attracted to the compound, mediated by receptors that are independent of Dop-1, leading to their death. The β-glucosides–positive (Bgl⁺) bacteria that are otherwise non-pathogenic can obtain additional nutrients from the dead predators, thereby switching their role from prey to predator. This study also offers an evolutionary explanation for the retention by bacteria of ‘cryptic’ or ‘silent’ genetic systems such as the bgl operon.     

Inhibition of actin polymerization decreases osteogeneic differentiation of mesenchymal stem cells through p38 MAPK pathway

Background

Mesenchymal Stem Cells (MSC) are important candidates for therapeutic applications due to their ex vivo proliferation and differentiation capacity. MSC differentiation is controlled by both intrinsic and extrinsic factors and actin cytoskeleton plays a major role in the event. In the current study, we tried to understand the initial molecular mechanisms and pathways that regulate the differentiation of MSC into osteocytes or adipocytes.

Results

We observed that actin modification was important during differentiation and differentially regulated during adipogenesis and osteogenesis. Initial disruption of actin polymerization reduced further differentiation of MSC into osteocytes and osteogenic differentiation was accompanied by increase in ERK1/2 and p38 MAPK phosphorylation. However, only p38 MAPK phosphorylation was down regulated upon inhibition of actin polymerization which as accompanied by decreased CD49E expression.

Conclusion

Taken together, our results show that actin modification is a pre-requisite for MSC differentiation into osteocytes and adipocytes and osteogenic differentiation is regulated through p38 MAPK phosphorylation. Thus by modifying their cytoskeleton the differentiation potential of MSC could be controlled which might have important implications for tissue repair and regeneration.