Callus Cultures from Zygotic Embryos of Costus speciosus and Their Morphogenetic Responses

Soft, nodular and hard types of calli were initiated on mature zygotic embryo explants of two tetraploid clones of Costus speciosus, of which, only the hard calli were amenable to morphogenetic responses. The two clones differed in their growth regulator requirements both for the initiation of calli and for shoot regeneration. De novo formation of both shoot bud meristems and somatic embryoids were observed. Latter were encased partially or fUlly by coleoptilar sheath. Embryoids could be isolated as discrete units. On maturity, a stock like appendage developed from the base and finally embryoids got detached from the subtending tissue. Both shoot-bud meristems and somatic embryoids developed into complete plantlets, the former upon sequential transfer of calli on Schenk and Hildebrandt’s (SH) basal medium containing lower levels of growth hormones, while the latter only on basal medium. These culture regenerants were subsequently transferred to the field. The morphogenetic behaviour of these two tetraploid clones reflects their marked genotypic difference inspite of their same ploidy status.     

Evaluation of genus <Emphasis Type="Italic">Cenchrus</Emphasis> based on malondialdehyde,proline content,specific leaf area and carbon isotope discrimination for drought tolerance and divergence of species at DNA level

Cenchrus (family Poaceae) is an important component of major grass covers of the world. Largely it is apomictic and both annual and perennial species exist in nature. Variations in contents of malondialdehyde, proline, specific leaf area and carbon isotope discrimination for drought tolerance were estimated among eight prominent species of Cenchrus. Simultaneously, genetic variations were also estimated by employing 187 RAPD primers. Of these, 23 primers did not react, 2 performed poorly and 7 produced many non-scorable bands and one primer yielded a single monomorphic band. Rest of the 154 primers generated one or more unambiguously scorable fragments. Twelve hundred and four of the 1,296 putative loci were polymorphic (93%) between at least one pair-wise comparisons among eight species. Dice coefficient and neighbor-joining algorithm analyses showed clustering patterns that fit with the known habitat of the species except perennial, C. myosuroides which formed a node between two annuals species. When these species were subjected to water stress tolerance test, a correlation (r = 0.612) between specific leaf area (SLA) and carbon isotope discrimination (CID) and difference in levels of drought tolerance based parameters among eight species were observed. Of the eight species investigated two annuals viz., C. biflorus and C. echinatus showed highest level of genetic similarity which was also evident from the similar levels of SLA, MDA, proline contents and carbon isotope discrimination values observed in these two species.     

Prevalence of <Emphasis Type="Italic">H. influenzae</Emphasis> type b &; f among unvaccinated patients with respiratory tract infection and meningitis

Haemophilus influenzae type b meningitis has been reported predominantly among infants who have not completed the primary immunization series, whereas infection by capsular f has been reported mostly in patients with significant underlying diseases. The present study analyses H. influenzae type b & f infection among 25 unvaccinated patients with respiratory tract infections and symptoms of meningitis by PCR. 5/7 isolates from CSF sample were capsular type b; whereas capsular type f was detected in 2/10 and 5/8 isolates from throat swab and sputum samples, respectively. Rest 13 strains were negative for both the capsular types. To conclude, in India where H. influenzae type b conjugate vaccine is not included in national immunization program, individuals with respiratory tract infections and meningitis are at a greater risk of developing infection with H. influenzae type b strains along with other capsular types and non-capsular types.     

Growth and alkaloid production along with expression profiles of biosynthetic pathway genes in two contrasting morphotypes of prickly and prickleless Solanum viarum Dunal

Protoplasma - Growth and production kinetics of three important glycoalkaloids viz. α-solanine, solanidine, and solasodine in two contrasting prickly and prickleless plants of Solanum viarum...     

Cbl-b Is a Novel Physiologic Regulator of Glycoprotein VI-dependent Platelet Activation

Cbl-b, a member of the Cbl family of E3 ubiquitin ligases, plays an important role in the activation of lymphocytes. However, its function in platelets remains unknown. We show that Cbl-b is expressed in human platelets along with c-Cbl, but in contrast to c-Cbl, it is not tyrosine-phosphorylated upon glycoprotein VI (GPVI) stimulation. Cbl-b, unlike c-Cbl, is not required for Syk ubiquitylation downstream of GPVI activation. Phospholipase Cγ2 (PLCγ2) and Bruton''s tyrosine kinase (BTK) are constituently associated with Cbl-b. Cbl-b-deficient (Cbl-b^−/−) platelets display an inhibition in the concentration-response curve for GPVI-specific agonist-induced aggregation, secretion, and Ca²⁺ mobilization. A parallel inhibition is found for activation of PLCγ2 and BTK. However, Syk activation is not affected by the absence of Cbl-b, indicating that Cbl-b acts downstream of Syk but upstream of BTK and PLCγ2. When Cbl-b^−/− mice were tested in the ferric chloride thrombosis model, occlusion time was increased and clot stability was reduced compared with wild type controls. These data indicate that Cbl-b plays a positive modulatory role in GPVI-dependent platelet signaling, which translates to an important regulatory role in hemostasis and thrombosis in vivo.     

Increase in Serum Ca2+/Mg2+ Ratio Promotes Proliferation of Prostate Cancer Cells by Activating TRPM7 Channels

TRPM7 is a novel magnesium-nucleotide-regulated metal current (MagNuM) channel that is regulated by serum Mg²⁺ concentrations. Changes in Mg²⁺ concentration have been shown to alter cell proliferation in various cells; however, the mechanism and the ion channel(s) involved have not yet been identified. Here we demonstrate that TRPM7 is expressed in control and prostate cancer cells. Supplementation of intracellular Mg-ATP or addition of external 2-aminoethoxydiphenyl borate inhibited MagNuM currents. Furthermore, silencing of TRPM7 inhibited whereas overexpression of TRPM7 increased endogenous MagNuM currents, suggesting that these currents are dependent on TRPM7. Importantly, although an increase in the serum Ca²⁺/Mg²⁺ ratio facilitated Ca²⁺ influx in both control and prostate cancer cells, a significantly higher Ca²⁺ influx was observed in prostate cancer cells. TRPM7 expression was also increased in cancer cells, but its expression was not dependent on the Ca²⁺/Mg²⁺ ratio per se. Additionally, an increase in the extracellular Ca²⁺/Mg²⁺ ratio led to a significant increase in cell proliferation of prostate cancer cells when compared with control cells. Consistent with these results, age-matched prostate cancer patients also showed a subsequent increase in the Ca²⁺/Mg²⁺ ratio and TRPM7 expression. Altogether, we provide evidence that the TRPM7 channel has an important role in prostate cancer and have identified that the Ca²⁺/Mg²⁺ ratio could be essential for the initiation/progression of prostate cancer.     

Expression,purification and substrate specificities of 3-nitrotoluene dioxygenase from Diaphorobacter sp. strain DS2

3-Nitotoluene dioxygenase (3-NTDO) is the first enzyme in the degradation pathway of 3-nitrotoluene (3-NT) by Diaphorobacter sp. strain DS2. The complete gene sequences of 3-NTDO were PCR amplified from genomic DNA of Diaphorobacter sp., cloned, sequenced and expressed. The 3-NTDO gene revealed a multi component structure having a reductase, a ferredoxin and two oxygenase subunits. Clones expressing the different subunits were constructed in pET21a expression vector system and overexpressed in E. coli BL21(DE3) host. Each subunit was individually purified separately to homogeneity. The active recombinant enzyme was reconstituted in vitro by mixing all three purified subunits. The reconstituted recombinant enzyme could catalyse biotransformations on a variety of organic aromatics.     

Non-Consent to a Wrist-Worn Accelerometer in Older Adults: The Role of Socio-Demographic,Behavioural and Health Factors

Background

Accelerometers, initially waist-worn but increasingly wrist-worn, are used to assess physical activity free from reporting-bias. However, its acceptability by study participants is unclear. Our objective is to assess factors associated with non-consent to a wrist-mounted accelerometer in older adults.

Methods

Data are from 4880 Whitehall II study participants (1328 women, age range = 60–83), requested to wear a wrist-worn accelerometer 24 h every day for 9 days in 2012/13. Sociodemographic, behavioral, and health-related factors were assessed by questionnaire and weight, height, blood pressure, cognitive and motor function were measured during a clinical examination.

Results

210 participants had contraindications and 388 (8.3%) of the remaining 4670 participants did not consent. Women, participants reporting less physical activity and less favorable general health were more likely not to consent. Among the clinical measures, cognitive impairment (Odds Ratio = 2.21, 95% confidence interval: 1.22–4.00) and slow walking speed (Odds Ratio = 1.38, 95% confidence interval: 1.02–1.86) were associated with higher odds of non-consent.

Conclusions

The rate of non-consent in our study of older adults was low. However, key markers of poor health at older ages were associated with non-consent, suggesting some selection bias in the accelerometer data.     

Tyrphostin-A47 inhibitable tyrosine phosphorylation of flagellar proteins is associated with distinct alteration of motility pattern in hamster spermatozoa

To acquire fertilizing potential, mammalian spermatozoa must undergo capacitation and acrosome reaction. Our earlier work showed that pentoxifylline (0.45 mM), a sperm motility stimulant, induced an early onset of hamster sperm capacitation associated with tyrosine phosphorylation of 45-80 kDa proteins, localized to the mid-piece of the sperm tail. To assess the role of protein tyrosine phosphorylation in sperm capacitation, we used tyrphostin-A47 (TP-47), a specific protein tyrosine kinase inhibitor. The dose-dependent (0.1-0.5 mM) inhibition of tyrosine phosphorylation by TP-47 was associated with inhibition of hyperactivated motility and 0.5 mM TP-47-treated spermatozoa exhibited a distinct circular motility pattern. This was accompanied by hypo-tyrosine phosphorylation of 45-60 kDa proteins, localized to the principal piece of the intact-sperm and the outer dense fiber-like structures in detergent treated-sperm. Sperm kinematic analysis (by CASA) of spermatozoa, exhibiting circular motility (at 1st hr), showed lower values of straight line velocity, curvilinear velocity and average path velocity, compared to untreated controls. Other TP-47 analogues, tyrphostin-AG1478 and -AG1296, had no effect either on kinematic parameters or sperm protein tyrosine phosphorylation. These studies indicate that TP-47-induced circular motility of spermatozoa is compound-specific and that the tyrosine phosphorylation status of 45-60 kDa flagellum-localized proteins could be key regulators of sperm flagellar bending pattern, associated with the hyperactivation of hamster spermatozoa.