Receptor-induced phosphorylation by mammary-derived growth factor 1 in mammary epithelial cell lines.

Previous work has shown that a mammary-derived growth factor (MDGF1), a human milk-derived, acidic, 62-kDa, N-glycosylated growth factor binds to cell surface receptors and stimulates proliferation of mammary epithelial cells. An 18-amino acid N-terminal partial sequence of the factor did not show any homology to other known growth factors or proteins. Using polyclonal antiserum raised against the synthetic peptide, we demonstrated that conditioned medium prepared from human breast cancer cell lines contains the factor. The antibody could adsorb the biological activity of the factor present in the conditioned medium. Earlier experiments on receptor cross-linking indicated that the receptor was approximately 120-140 kDa. Since tyrosine phosphorylation plays a crucial role in cell proliferation and cell transformation, experiments were conducted to find out whether MDGF1 induces the appearance of phosphotyrosine in MDGF1-receptor-positive MDA-MB 468, MCF-7, and 184A1N4 cell lines compared to receptor-negative lines. Western blot analysis using monoclonal antiphosphotyrosine indicated that MDGF1 induces phosphotyrosine in a 180-185-kDa protein in MDGF1 receptor-positive cell lines. Phosphorylation was not blocked and phosphorylated proteins were not immunoprecipitated by an antibody directed against the binding site of the EGF receptor. Cell membrane fractionation demonstrated that phosphorylation induced by MDGF1 was membrane-associated. The nature of this 180-185-kDa protein and its possible relationship to the MDGF1 receptor are under investigation.     

Effects of exogenously applied plant growth regulators in combination with PGPR on the physiology and root growth of chickpea (Cicer arietinum ) and their role in drought tolerance

Both the plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) exert beneficial effects on plant growth even under stress, but combined effect of both of them has not been evaluated yet. Present investigation was aimed to determine the responses of 2 chickpea varieties (differing in drought tolerance) to 3 PGPR viz. Bacillus subtilis, Bacillus thuringiensis and Bacillus megaterium and PGR (SA and Putrescine) on physiology of chickpea grown in sandy soil. The PGR, Salicylic acid (SA) and Putrescine (Put) were sprayed on the seedling 20 days after germination. Results revealed, synergistic effects of PGPR and PGR on chlorophyll, protein and sugar contents. Addition of PGR to PGPR inoculated plants assisted the plant in osmoregulation and amelioration of oxidative stresses and in induction of new proteins. Combined application of PGR and PGPR decreased lipid peroxidation more effectively but increased the leaf area. It is inferred that PGPR and PGR work synergistically to promote growth of plants under moisture and nutrient deficit condition of sandy soil. Since, SA induces Systemic Acquired Resistance (SAR) in plants hence the addition of SA along with PGPR may render the plant more productive and better tolerant to diseases/pathogen attack.     

Characterization of dextransucrase immobilized on calcium alginate beads from Leuconostoc mesenteroides PCSIR-4

Immobilization of dextransucrase from Leuconostoc mesenteroides PCSIR-4 on alginate is optimized for application in the production of dextran from sucrose. Dextransucrase was partially purified by ethanol upto 2.5 fold. Properties of dextransucrase were less affected by immobilization on alginate beads from soluble enzyme. Highest activities of both soluble and immobilized dextransucrase found to be at 35 degrees C and optimum pH for activity remain 5.00. Substrate maxima for immobilized enzyme changed from 125 mg/ml to 200 mg/ml. Incubation time for enzyme-substrate reaction for maximum enzyme activity was increased from 15 minutes to 60 minutes in case of immobilized enzyme. Maximum stability of immobilized dextransucrase was achieved at 25 degrees C with respect to time.     

Analyzing the role of cannabinoids as modulators of Wnt/β-catenin signaling pathway for their use in the management of neuropathic pain

Neuropathic pain is a debilitating form of treatment-resistant chronic pain caused by damage to the nervous system. Cannabinoids have been known for suppressing neuropathic pain by modulating the endo cannabinoid system. Since the canonical Wnt/β-catenin signaling has recently been implicated in pain sensation, we investigated the impact of major cannabinoids (1–6) from the leaves of Cannabis sativa and an epoxy derivative of compound 2, here upon referred to as 2a, on modulating Wnt/β-catenin signaling pathway. The results presented in this study show that compound 1, 2 and 2a exhibited potent inhibitory activity against Wnt/β-catenin pathway in a dose-dependent manner. Compound 2a was seen to inhibit this pathway at slightly lower concentrations than its parent molecule 2, under similar conditions. Taken together, compound 1, 2 and 2a, by virtue of their inhibition of Wnt/β-catenin signaling pathway, could be developed as effective neuroprotective agents for the management of neuropathic pain.     

Does Mortality Vary between Asian Subgroups in New Zealand: An Application of Hierarchical Bayesian Modelling

The aim of this paper was to see whether all-cause and cause-specific mortality rates vary between Asian ethnic subgroups, and whether overseas born Asian subgroup mortality rate ratios varied by nativity and duration of residence. We used hierarchical Bayesian methods to allow for sparse data in the analysis of linked census-mortality data for 25–75 year old New Zealanders. We found directly standardised posterior all-cause and cardiovascular mortality rates were highest for the Indian ethnic group, significantly so when compared with those of Chinese ethnicity. In contrast, cancer mortality rates were lowest for ethnic Indians. Asian overseas born subgroups have about 70% of the mortality rate of their New Zealand born Asian counterparts, a result that showed little variation by Asian subgroup or cause of death. Within the overseas born population, all-cause mortality rates for migrants living 0–9 years in New Zealand were about 60% of the mortality rate of those living more than 25 years in New Zealand regardless of ethnicity. The corresponding figure for cardiovascular mortality rates was 50%. However, while Chinese cancer mortality rates increased with duration of residence, Indian and Other Asian cancer mortality rates did not. Future research on the mechanisms of worsening of health with increased time spent in the host country is required to improve the understanding of the process, and would assist the policy-makers and health planners.     

Diarrheagenic Escherichia coli Carrying Supplementary Virulence Genes Are an Important Cause of Moderate to Severe Diarrhoeal Disease in Mexico

Diarrheagenic Escherichia coli (DEC) cause acute and persistent diarrhoea worldwide, but little is known about their epidemiology in Mexico. We determined the prevalence of bacterial enteropathogens in 831 children with acute diarrhoea over a four-year period in Yucatan, Mexico. Six DEC supplementary virulence genes (SVG), mainly associated with enteroaggregative E. coli (EAEC), were sought in 3100 E. coli isolates. DEC was the most common bacterial enteropathogen (28%), surpassing Salmonella (12%) and Shigella (9%). Predominant DEC groups were diffusely adherent E. coli (DAEC) (35%), EAEC (24%), and enteropathogenic E. coli (EPEC) (19%). Among children with DEC infections, 14% had severe illness mainly caused by EPEC (26%) and DAEC (18%); 30% had moderate diarrhoea mainly caused by DAEC (36%), mixed DEC infections (33%) and EAEC (32%). DAEC was most prevalent during spring, while ETEC, EAEC and EPEC predominated in summer. EAEC was more frequent in children 6–24 months old than in those younger than 6 months of age (P = 0.008, OR = 4.2, 95% CI, 1.3–13.9). The presence of SVG dispersin, (aatA), dispersin-translocator (aatA), enteroaggregative heat-stable toxin 1 (astA), plasmid encoded toxin (pet), cytolethal distending toxin (cdt) was higher in DEC than non-DEC strains, (36% vs 26%, P <0.0001, OR = 1.5, 95% CI, 1.3–1.8). 98% of EAEC-infected children harboured strains with SVG; 85% carried the aap-aatA gene combination, and 33% of these also carried astA. 28% of both EPEC and ETEC, and 6% of DAEC patients had strains with SVG. 54% of EPEC patients carried pet-positive strains alone or in combination with astA; only this DEC group harboured cdt-positive isolates. All ETEC patients carried astA- or astA-aap-positive strains. astA and aap were the most common SVG in DAEC (3% and 2%) and non-DEC strains (21% and 13%). DEC carrying SVG are an important cause of moderate to severe bacterial diarrhoea in Mexican children.     

Ammonia-oxidizing Archaea in the Arctic Ocean and Antarctic coastal waters

We compared abundance, distributions and phylogenetic composition of Crenarchaeota and ammonia-oxidizing Archaea (AOA) in samples collected from coastal waters west of the Antarctic Peninsula during the summers of 2005 and 2006, with samples from the central Arctic Ocean collected during the summer of 1997. Ammonia-oxidizing Archaea and Crenarchaeota abundances were estimated from quantitative PCR measurements of amoA and 16S rRNA gene abundances. Crenarchaeota and AOA were approximately fivefold more abundant at comparable depths in the Antarctic versus the Arctic Ocean. Crenarchaeota and AOA were essentially absent from the Antarctic Summer Surface Water (SSW) water mass (0–45 m depth). The ratio of Crenarchaeota 16S rRNA to archaeal amoA gene abundance in the Winter Water (WW) water mass (45–105 m depth) of the Southern Ocean was much lower (0.15) than expected and in sharp contrast to the ratio (2.0) in the Circumpolar Deep Water (CDW) water mass (105–3500 m depth) immediately below it. We did not observe comparable segregation of this ratio by depth or water mass in Arctic Ocean samples. A ubiquitous, abundant and polar-specific crenarchaeote was the dominant ribotype in the WW and important in the upper halocline of the Arctic Ocean. Our data suggest that this organism does not contain an ammonia monooxygenase gene. In contrast to other studies where Crenarchaeota populations apparently lacking amoA genes are found in bathypelagic waters, this organism appears to dominate in well-defined, ammonium-rich, near-surface water masses in polar oceans.