Self-Purificatory Ganga Water Facilitates Death of Pathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> O157:H7

Concern over the prevalence of active pharmaceutical agents and subsequent occurrence of antimicrobial resistance in the environment is increasing. Incorruptible ability of Ganga water was evaluated using fresh, 8-year-old, and 16-year-old Ganga water samples spiked with pathogenic Escherichia coli serotype O157:H7. Survival of E. coli O157:H7 over the course of the experiment was 3, 7, and 15 days for fresh, 8-year-old, and 16-year-old Ganga waters, respectively. On the contrary, in Milli Q water the decline in viable count of E. coli O157:H7 up to 30 days was only 2 log units. Survival of E. coli O157:H7 was greater in boiled water compared with water after passage through a 0.2-μm-pore-size membrane filter, indicating involvement of heat-labile agents influencing survival of E. coli O157:H7 in Ganga water, which seems to indicate the role of antimicrobial peptides. Functional diversity of Ganga water’s native microbial community structure as assessed with Biolog Eco plates was not affected even in the presence of a 5-fold log units higher pathogenic load of E. coli O157:H7. These findings suggest that Ganga water has certain novel antimicrobial attributes, besides its remarkable fluidity, which may provide a much-needed basis for the development of new antimicrobial compounds.     

Analysis of the role of mitochondrial and endoplasmic reticulum localized small heat shock proteins in tomato

This communication examines the role of small heat shock proteins (sHsps) targeted to mitochondria (Mt) and endoplasmic reticulum (ER) in tomato plants (Lycopersicon esculentum Mill.) under heat stress. Genetic response of transgenic and wild type plants varied under optimum, moderately elevated and elevated temperature. In optimum temperature higher biomass was recorded in wild type than the transgenic lines, whereas in moderately elevated temperature biomass increased in Mt-sHsp line. Also, net photosynthetic rate (P_N) increased in Mt-sHsp line in both the elevated temperatures, though higher in moderately elevated. Cell membrane stability (CMS) improved in all the lines after exposure to elevated temperatures, but always remained higher in transgenic lines. Transgenic lines expressed sHsps in different temperature regimes in both vegetative and reproductive parts, while wild type expressed such proteins only after 1 h of heat shock.     

The purB gene controls rhizosphere colonization by Pantoea agglomerans

Aims: To isolate the rhizosphere competence‐defective transposon Tn5 mutant of Pantoea agglomerans NBRISRM (SRM) and to identify the gene causing defect in its root colonization ability. Methods and Results: From over 5000 clones containing Tn5, one mutant P. agglomerans NBRISRMT (SRMT) showing 6 log units less colonization when compared with SRM, after 30 days in sand‐nonsterilized soil assay system was selected for further work to determine the effects of the mutation on rhizosphere competence. Southern hybridization analysis of restricted genomic DNA of SRMT demonstrated that the mutant had a single Tn5 insert. SRM increased in titre to about 2 × 10⁸ CFU g^?1 root, compared with the indigenous bacterial population of heterotrophs of about 5 × 10⁷ CFU g^?1 root. In contrast, 30 days later, the titre value of SRMT was almost undetectable at 1 × 10² CFU g^?1 root, demonstrating its inability to survive and colonize the rhizosphere. Sequencing of the flanking region of the Tn5 mutant revealed that Tn5 disrupted the purB gene. Conclusions: A defect in the colonization phenotype of the SRMT was attributed to the disruption in adenylosuccinate lyase (EC 4.3.2.2) which is encoded by the pur B gene and is required for rhizosphere colonization in P. agglomerans. Significantly less exopolysaccharide and biofilm was formed by SRMT when compared to SRM, because of the disruption of the purB gene. Significance and Impact of the Study: This work provides the first evidence for a functional role of purB gene in rhizosphere competence and root colonization by any rhizobacteria.     

Crossing the Limits of Rhizobium Existence in Extreme Conditions

An ecological survey was conducted to characterize 5000 Rhizobium sp. sesbania strains of diverse geographical origin, isolated from the root nodules of Sesbania aculeata growing in neutral (pH 7) and alkaline (pH 8.5 and above) soils. The rhizobia from the alkaline soil showed significantly higher salt tolerance than those isolated from neutral soil. Upper limits of stress survival of rhizobial isolates, Rhizobium sp. NBRI0102 sesbania selected from neutral soil, and Rhizobium sp. NBRI2505 sesbania selected from alkaline soil, were studied under free living conditions. Rhizobium sp. NBRI0102 sesbania and Rhizobium sp. NBRI2505 sesbania tolerated yeast extract mannitol broth (YEB) containing 10% and 28% salt (NaCl, wt/vol) for up to 18 h of incubation at 30°C. Growth of Rhizobium sp. NBRI0102 sesbania and Rhizobium sp. NBRI2505 sesbania at pH 7, 11, and 12 was identical, except for a lag period of about 10 h in the growth of Rhizobium sp. NBRI0102 sesbania at pH 11 and 12, as compared with pH 7. Rhizobium sp. NBRI0102 sesbania and Rhizobium sp. NBRI2505 sesbania survived at 50°C and 65°C, in YEB at pH 7 for up to 4 and 2 h, respectively. To our knowledge, this is the first report of rhizobia demonstrating survival of Rhizobium sp. NBRI2505 sesbania, estimated by counting viable cells, to such extreme conditions of salt and temperature, individually. In contrast to Rhizobium sp. NBRI0102 sesbania, high temperature was tolerated efficiently by Rhizobium sp. NBRI2505 sesbania, in the presence of salt at higher pH. Our results suggest that the possession of the trait of high salt tolerance might be of some evolutionary significance for the survival of rhizobia in alkaline soils, at high pH and temperature. Received: 23 May 2000 / Accepted: 26 June 2000     

Deregulation of the serum- and glucocorticoid-inducible kinase SGK1 in the endometrium causes reproductive failure

Infertility and recurrent pregnancy loss (RPL) are prevalent but distinct causes of reproductive failure that often remain unexplained despite extensive investigations. Analysis of midsecretory endometrial samples revealed that SGK1, a kinase involved in epithelial ion transport and cell survival, is upregulated in unexplained infertility, most prominently in the luminal epithelium, but downregulated in the endometrium of women suffering from RPL. To determine the functional importance of these observations, we first expressed a constitutively active SGK1 mutant in the luminal epithelium of the mouse uterus. This prevented expression of certain endometrial receptivity genes, perturbed uterine fluid handling and abolished embryo implantation. By contrast, implantation was unhindered in Sgk1-/- mice, but pregnancy was often complicated by bleeding at the decidual-placental interface and fetal growth retardation and subsequent demise. Compared to wild-type mice, Sgk1-/- mice had gross impairment of pregnancy-dependent induction of genes involved in oxidative stress defenses. Relative SGK1 deficiency was also a hallmark of decidualizing stromal cells from human subjects with RPL and sensitized these cells to oxidative cell death. Thus, depending on the cellular compartment, deregulated SGK1 activity in cycling endometrium interferes with embryo implantation, leading to infertility, or predisposes to pregnancy complications by rendering the feto-maternal interface vulnerable to oxidative damage.     

Phenological variations of primary biochemicals in male and female plants of Hippophae salicifolia D. Don

Journal of Plant Biochemistry and Biotechnology - Dioecious nature of a plant shows variations in male and female individuals of that species, due to their differential role in sexual reproduction....     

Net photosynthetic rate in peanut (Arachis hypogaea L.): Influence of leaf position,time of day,and reproductive-sink

Net photosynthetic rate (P_N) was studied in field-grown peanut cv. GG 2 in relation to leaf position, time of day, reproductive-sink, and phenophase. In general, P_N remained higher in the upper leaves (first from top to the fourth) than in the lower leaves (fifth to eighth). The mean P_N of the leaves situated upper and the leaves lower in the canopy increased from the morning, reached a maximum during noon hours, and decreased thereafter. Between 09:00 to 10:00 h, P_N, stomatal conductance (g_s), and transpiration rate (E) in the upper leaves were higher than in the lower leaves, but between 12:00 and 13:00 h, these activities increased significantly in the lower leaves. Highest P_N was found during pod-development phase. Removal of flowers, and hence of active reproductive-sink, decreased plant height and number of leaves, and initiated accumulation of photosynthates in the leaves. The P_N per unit leaf area in plants with reproductive-sink (WRS) was similar to those without reproductive-sink (WORS). However, leaf area of WORS plants decreased significantly, mainly due to the reduction in number of leaves. No feed-back inhibition of P_N (per unit leaf area) was found despite accumulation of photosynthates in the leaves as a result of removal of the active reproductive-sink. This revised version was published online in September 2006 with corrections to the Cover Date.     

Lead induced antioxidant defense system in pigeon pea and its impact on yield and quality of seeds

Toxic effects of lead (>0.2 mM Pb) were measured in pigeon pea (Cajanus cajan Mill) cv. UPAS grown in sand culture as reduction in growth, yield, and quality of seeds. Leaves containing >38 μg g⁻¹ Pb showed oxidative damage as decrease in chlorophyll content and induction of antioxidants such as carotenoids, proline, and non-protein thiol contents with enhanced activities of SOD and peroxidase. At excess (>0.2 mM) Pb, accumulation of >1,000 μg Pb g⁻¹ root tissue was associated with increase in non-protein thiol content. It is concluded that inhibition in root-to-shoot translocation of Pb and induction in the level of proline, chloroplast pigments, and non-protein thiols and activities of antioxidant enzymes SOD and peroxidase at <0.2 mM Pb could have protected the pigeon pea plants from the deleterious effects of Pb. However, excess Pb at >0.2 mM showed a decline in yield, boldness, and quality of seeds despite the expression of an additional band each of Cu–Zn SOD and peroxidase isoform. The threshold of toxicity and toxicity values in pigeon pea leaves of plants exhibiting 10 and 33% yield depression at 27 days after metal supply were 27 and 56 μg Pb g⁻¹, respectively.