Salt Stress Induced Changes in Growth and Enzyme Activities in Germinating Phaseolus Mungo Seeds

NaCl salt stress induced changes in growth and enzyme activities in blackgram (Phaseolus mungo L.) seeds during germination were studied. A decrease in germination percentage, root length, shoot length, and fresh mass was noticed with an increase in NaCl concentration. With the increase in NaCl concentration and duration of stress proline content increased and catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities decreased.     

Biochemical characterization of Escherichia coli DNA helicase I

The gene product of F tral is a bifunctional protein which nicks and unwinds the F plasmid during conjugal DNA transfer. Further biochemical characterization of the Tral protein reveals that it has a second, much lower, Km for ATP hydrolysis, in addition to that previously identified. Measurement of the single-stranded DNA-stimulated ATPase rate indicates that there is co-operative interaction between the enzyme monomers for maximal activity. Furthermore, 18O-exchange experiments indicate that Tral protein hydrolyses ATP with, at most, a low-level reversal of the hydrolytic step during each turnover.     

Endophytic bacterial flora in the stem tissue of a tropical maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) genotype: isolation,identification and enumeration

The genotypic diversity of indigenous bacterial endophytes within stem of tropical maize (Zea mays L.) was determined in field and greenhouse experiments. Strains were isolated from stem tissues of a tropical maize cultivar (PEHM-1) by trituration and surface disinfestation and their population dynamics was determined. Endophytes were found in most of the growing season at populations ranging from 1.36–6.12 × 10⁵ colony-forming units per gram fresh weight (c.f.u./gm fw) of stem. Analysis of these bacterial endophytes using Gas Chromatography—Fatty Acid Methyl Ester (GC-FAME) led to the identification of Bacillus pumilus, B. subtilis, Pseudomonas aeruginosa and P. fluorescens as the relatively more predominant group of bacterial species residing in maize stem. When the maize seedlings grown in a greenhouse were inoculated with these four isolates individually, their population densities decreased (1.6–3.1 × 10⁵ c.f.u./gm fw of stem) as compared to the field-grown maize (1.8–3.8 × 10⁵ c.f.u./gm fw of stem). The highest persistence, however, was recovered in the case of B. subtilis with a population density of 3.1 × 10⁵ c.f.u./gm fw of stem tissue on 28 days after emergence (DAE). This is the first report on population dynamics of bacterial endophytes from tropical maize and the results establish that symptomless populations of bacteria exist in the maize stem.     

Frontal eye field inactivation alters the readout of superior colliculus activity for saccade generation in a task-dependent manner

Saccades require a spatiotemporal transformation of activity between the intermediate layers of the superior colliculus (iSC) and downstream brainstem burst generator. The dynamic linear ensemble-coding model (Goossens and Van Opstal 2006) proposes that each iSC spike contributes a fixed mini-vector to saccade displacement. Although biologically-plausible, this model assumes cortical areas like the frontal eye fields (FEF) simply provide the saccadic goal to be executed by the iSC and brainstem burst generator. However, the FEF and iSC operate in unison during saccades, and a pathway from the FEF to the brainstem burst generator that bypasses the iSC exists. Here, we investigate the impact of large yet reversible inactivation of the FEF on iSC activity in the context of the model across four saccade tasks. We exploit the overlap of saccade vectors generated when the FEF is inactivated or not, comparing the number of iSC spikes for metrically-matched saccades. We found that the iSC emits fewer spikes for metrically-matched saccades during FEF inactivation. The decrease in spike count is task-dependent, with a greater decrease accompanying more cognitively-demanding saccades. Our results show that FEF integrity influences the readout of iSC activity in a task-dependent manner. We propose that the dynamic linear ensemble-coding model be modified so that FEF inactivation increases the gain of a readout parameter, effectively increasing the influence of a single iSC spike. We speculate that this modification could be instantiated by FEF and iSC pathways to the cerebellum that could modulate the excitability of the brainstem burst generator.

     

Dopaminergic influence on thyrotropin secretion in primary hypothyroidism.

This study was conducted to assess the influence of dopamine on thyrotropin secretion in patients with primary hypothyroidism before and after optimized L-thyroxin replacement therapy. Thyrotropin responses to dopamine infusion (4 microg/kg/min over 3 hours) and IV metoclopramide (10 mg bolus), a dopamine receptor blocker were studied in 25 consecutive patients with primary hypothyroidism before and after achieving stable euthyroid state and compared with 15 normal age-matched controls. Thyrotropin response to both dopamine infusion (decremental) and IV metoclopramide bolus (incremental) was greater in patients with primary hypothyroidism than that in the control subjects. Thyrotropin response was greater in women than in men. The magnitude of decremental thyrotropin response to dopamine infusion and the incremental response to IV metoclopramide bolus significantly correlated with the basal T3 and T4 levels. Thyrotropin response was blunted to dopamine infusion but not to metoclopramide at follow-up after six-month replacement with L-thyroxin, and both the responses were comparable in women and men in patient group. We conclude that modulation of dopaminergic system by dopamine or by dopamine receptor blocker has a greater influence on thyrotropin secretion in patients with primary hypothyroidism than euthyroid normal subjects.     

Family studies on transverse fronto-parietal index

In the present paper an attempt has been made to study the Transverse Fronto-parietal Index on 200 biological families with 577 children, taking the age and the sex of the individuals into consideration. The present study on 200 Punjabi families hints at the dominating nature of the mesometopic type (70.4–74.9) as evidenced from the index value.     

Optimization,purification, and characterization of L-asparaginase from Actinomycetales bacterium BkSoiiA

Actinobacteria are promising source of a wide range of important enzymes, some of which are produced in industrial scale, with others yet to be harnessed. L-Asparaginase is used as an antineoplastic agent. The present work deals with the production and optimization of L-asparaginase from Actinomycetales bacterium BkSoiiA using submerged fermentation in M9 medium. Production optimization resulted in a modified M9 medium with yeast extract and fructose as carbon and nitrogen sources, respectively, at pH 8.0, incubated for 120 hr at 30 ± 2°C. The crude enzyme was purified to near homogeneity by ammonium sulfate precipitation following dialysis, ion-exchange column chromatography, and finally gel filtration. The sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) revealed an apparent molecular weight of 57 kD. The enzyme was purified 95.06-fold and showed a final specific activity of 204.37 U/mg with 3.49% yield. The purified enzyme showed maximum activity at a pH 10.0 and was stable at pH 7.0 to 9.0. The enzyme was activated by Mn²⁺ and strongly inhibited by Ba²⁺. All these preliminary characterization suggests that the L-asparaginase from the source may be a tool useful to pharmaceutical industries after further research.     

Effect of Peroxides on [3H]d-Aspartate Release from Bovine Isolated Retinae

In the present study, we investigated the effect of naturally occurring and synthetic peroxides on K+-depolarization-evoked release of [3H]D-aspartate from bovine isolated retinae. Furthermore, effect of peroxides on endogenous glutamate concentrations were measured by HPLC in bovine neural retinae and vitreous humor of eyes treated with hydrogen peroxide (H2O2) ex vivo. Both naturally occurring H2O2 (1-100 microM) and synthetic (cumene hydroperoxide, cuOOH; 1-100 microM) peroxides caused a concentration-dependent inhibition of K+-evoked [3H]D-aspartate release without affecting basal tritium efflux. The antioxidant, trolox (2 mM) prevented the inhibition of evoked [3H]D-aspartate overflow elicited by both H2O2 (30 microM) and cuOOH (10 microM). Inhibition of catalase by 3-amino-triazole (3- AT 100 mM) enhanced an inhibitory effect of a low concentration of H2O2 (1 microM) but antagonized the effect of H2O2 (30 microM) on K+-induced [3H]D-aspartate release. In ex vivo experiments, exogenously applied H2O2 (1-100 microM) also caused a concentration-related decrease in glutamate levels in the bovine retina. We conclude that peroxides can inhibit K+-evoked release of [3H]D-aspartate and also decrease endogenous glutamate concentrations in the bovine retina.     

The role of neoadjuvant and adjuvant chemotherapy regimens consisting of different combinations of drugs in the treatment of advanced oral cancer

We performed a retrospective analysis on the effect of neoadjuvant chemotherapy with three cycles of methotrexate (100 mg/m² on day 1), cisplatin (90 mg/m² on day 1) and bleomycin (20 mg/m² on day 1–5) with 21 d gap between each cycle in 44 patients with advanced squamous cell carcinoma of the cheek, lip and tongue followed by surgery and adjuvant chemotherapy consisting of cisplatin (90 mg/m² on day 1), Mitomycin C (6 mg/m² on day 1) and 5-fluorouracil (1000 mg/m² 120 h continuous infusion from day 1) repeated every 3 weeks for three cycles. Following induction chemotherapy, complete response was observed in 11 out of 44 patients (25%), and a partial response in a further 28 patients (64%). The overall median survival of all patients was 29 months and those in stage III and stage IV were 30 and 15 months respectively (P<0.001). The median duration of the time to relapse in patients who responded to adjuvant chemotherapy was 28 months. The main toxic effect was vomiting followed by hematological toxicity. No treatment-related deaths occurred. The regimen showed a significant response, encouraging median survival and a good tolerability profile.