Cloning and characterization of a new hetero-gene cluster of nonribosomal peptide synthetase and polyketide synthase from the cyanobacterium Microcystis aeruginosa K-139

Two nonribosomal peptide synthetase genes responsible for the biosynthesis of microcystin and micropeptin in Microcystis aeruginosa K-139 have been identified. A new nonribosomal peptide synthetase gene, psm3, was identified in M. aeruginosa K-139. The gene is a cluster extending 30 kb and comprising 13 bidirectionally transcribed open reading frames arranged in two putative operons. psm3 encodes four adenylation proteins, one polyketide synthase, and several unique proteins, especially Psm3L consisting of halogenase, acyl-CoA binding protein-like protein, and acyl carrier protein. Alignment of the binding pocket of the adenylation domain and an ATP-PPi exchange analysis using a recombinant protein with the adenylation domain of Psm3B showed that Psm3G and Psm3B activate aspartic acid and tyrosine, respectively. Although disruption of psm3 did not reveal the product produced by Psm3, we identified microviridin B and aeruginosin K139 in the cells of M. aeruginosa K-139. The above-mentioned results indicated that M. aeruginosa possesses at least five nonribosomal peptide synthetase gene clusters.     

Preliminary investigations on inducing salt tolerance in maize through inoculation with rhizobacteria containing ACC deaminase activity

Twenty rhizobacterial strains containing 1-aminocyclopropane-1-carboxylate deaminase were isolated from the rhizosphere of salt-affected maize fields. They were screened for their growth-promoting activities under axenic conditions at 1, 4, 8, and 12 dS x m-1 salinity levels. Based upon the data of the axenic study, the 6 most effective strains were selected to conduct pot trials in the wire house. Besides one original salinity level (1.6 dS x m-1), 3 other salinity levels (4, 8, and 12 dS x m-1) were maintained in pots and maize seeds inoculated with selected strains of plant growth-promoting rhizobacteria, as well as uninoculated controls were sown. Results showed that the increase in salinity level decreased the growth of maize seedlings. However, inoculation with rhizobacterial strains reduced this depression effect and improved the growth and yield at all the salinity levels tested. Selected strains significantly increased plant height, root length, total biomass, cob mass, and grain yield up to 82%, 93%, 51%, 40%, and 50%, respectively, over respective uninoculated controls at the electrical conductivity of 12 dS x m-1. Among various plant growth-promoting rhizobacterial strains, S5 (Pseudomonas syringae), S14 (Enterobacter aerogenes), and S20 (Pseudomonas fluorescens) were the most effective strains for promoting the growth and yield of maize, even at high salt stress. The relatively better salt tolerance of inoculated plants was associated with a high K+/Na+ ratio as well as high relative water and chlorophyll and low proline contents.     

Linking Plants Functioning to Adaptive Responses Under Heat Stress Conditions: A Mechanistic Review

Journal of Plant Growth Regulation - The general circulation models estimated an average increase in global surface temperature about 4 °C (2.9 to 5.5 °C). Escalating...     

Young Plasma Induces Antidepressant-Like Effects in Aged Rats Subjected to Chronic Mild Stress by Suppressing Indoleamine 2,3-Dioxygenase Enzyme and Kynurenine Pathway in the Prefrontal Cortex

Pathophysiology of depression in elderlies is linked to aging-associated increase in indoleamine 2,3-dioxygenase (IDO) levels and activity and kynurenine (Kyn) metabolites. Moreover, these aging-induced changes may alter the brain’s responses to stress. Growing evidence suggested that young plasma can positively affect brain dysfunctions in old age. The present study aimed to investigate whether the antidepressant effects of young plasma administration in aged rats subjected to chronic unpredictable mild stress (CUMS) and underlying mechanisms, focusing on the prefrontal cortex (PFC). Young (3 months old) and aged (22 months old) male rats were divided into five groups; young control, aged control, aged rats subjected to CUMS (A?+?CUMS), aged rats subjected to CUMS and treated with young plasma (A?+?CUMS?+?YP), and aged rats subjected to CUMS and treated with old plasma (A?+?CUMS?+?OP). Plasma was injected (1 ml, intravenously) three times per week for four weeks. Young plasma significantly improved CUMS-induced depressive-like behaviors, evidenced by the increased sucrose consumption ratio in the sucrose preference test and the reduced immobility time in the forced swimming test. Furthermore, young plasma markedly reduced the levels of interferon-gamma (IFN-γ), IDO, Kyn, and Kyn to tryptophan (Kyn/Trp) ratio in PFC tissue. Expression levels of the serotonin transporter and growth-associated protein (GAP)-43 were also significantly increased after chronic administration of young plasma. These findings provide evidence for the antidepressant effect of young plasma in old age; however, whether it improves depressive behaviors or faster recovery from stress-induced deficits is required to be elucidated.

     

A genome-wide approach to the comprehensive analysis of GASA gene family in Glycine max

Plant Molecular Biology - A vital role of short amino acid gene family, gibberellic acid stimulated arabidopsis (GASA), has been reported in plant growth and development. Although, little...     

Identification of a homozygous splice site mutation in the dynein axonemal light chain 4 gene on 22q13.1 in a large consanguineous family from Pakistan with congenital mirror movement disorder

Mirror movements (MRMV) are involuntary movements on one side of the body that mirror voluntary movements on the opposite side. Congenital mirror movement disorder is a rare, typically autosomal-dominant disorder, although it has been suspected that some sporadic cases may be due to recessive inheritance. Using a linkage analysis and a candidate gene approach, two genes have been implicated in congenital MRMV disorder to date: DCC on 18q21.2 (MRMV1), which encodes a netrin receptor, and RAD51 on 15q15.1 (MRMV2), which is involved in the maintenance of genomic integrity. Here, we describe a large consanguineous Pakistani family with 11 cases of congenital MRMV disorder reported across five generations, with autosomal recessive inheritance likely. Sanger sequencing of DCC and RAD51 did not identify a mutation. We then employed microarray genotyping and autozygosity mapping to identify a shared region of homozygosity-by-descent among the affected individuals. We identified a large autozygous region of ~3.3 Mb on chromosome 22q13.1 (Chr22:36605976?39904648). We used Sanger sequencing to exclude several candidate genes within this region, including DMC1 and NPTXR. Whole exome sequencing was employed, and identified a splice site mutation in the dynein axonemal light chain 4 gene, DNAL4. This splice site change leads to skipping of exon 3, and omission of 28 amino acids from DNAL4 protein. Linkage analysis using Simwalk2 gives a maximum Lod score of 6.197 at this locus. Whether or how DNAL4 function may relate to the function of DCC or RAD51 is not known. Also, there is no suggestion of primary ciliary dyskinesis, situs inversus, or defective sperm in affected family members, which might be anticipated given a putative role for DNAL4 in axonemal-based dynein complexes. We suggest that DNAL4 plays a role in the cytoplasmic dynein complex for netrin-1-directed retrograde transport, and in commissural neurons of the corpus callosum in particular. This, in turn, could lead to faulty cross-brain wiring, resulting in MRMV.     

Bacterial FHA domains: neglected players in the phospho-threonine signalling game?

Forkhead-associated (FHA) domains bind phospho-threonine peptides and are known to mediate phosphorylation-dependent protein–protein interactions in a variety of eukaryotic settings. However, their role in bacterial physiology and signalling has been largely neglected. We have surveyed bacterial FHA domains and discovered that they are implicated in many bacterial processes, including regulation of cell shape, type III secretion, sporulation, pathogenic and symbiotic host–bacterium interactions, carbohydrate storage and transport, signal transduction and ethambutol resistance. The way is now open to identify the targets of each FHA domain, and their roles in cellular physiology, and perhaps even to develop novel FHA-blocking antibacterial agents.     

SAS-4 is recruited to a dynamic structure in newly forming centrioles that is stabilized by the gamma-tubulin-mediated addition of centriolar microtubules

Centrioles are surrounded by pericentriolar material (PCM), which is proposed to promote new centriole assembly by concentrating gamma-tubulin. Here, we quantitatively monitor new centriole assembly in living Caenorhabditis elegans embryos, focusing on the conserved components SAS-4 and SAS-6. We show that SAS-4 and SAS-6 are coordinately recruited to the site of new centriole assembly and reach their maximum levels during S phase. Centriolar SAS-6 is subsequently reduced by a mechanism intrinsic to the early assembly pathway that does not require progression into mitosis. Centriolar SAS-4 remains in dynamic equilibrium with the cytoplasmic pool until late prophase, when it is stably incorporated in a step that requires gamma-tubulin and microtubule assembly. These results indicate that gamma-tubulin in the PCM stabilizes the nascent daughter centriole by promoting microtubule addition to its outer wall. Such a mechanism may help restrict new centriole assembly to the vicinity of preexisting parent centrioles that recruit PCM.