Multi-location evaluation of mungbean (Vigna radiata L.) in Indian climates: Ecophenological dynamics, yield relation, and characterization of locations

Crop yield varies considerably within agroecology depending on the genetic potential of crop cultivars and various edaphic and climatic variables. Understanding site-specific changes in crop yield and genotype × environment interaction are crucial and needs exceptional consideration in strategic breeding programs. Further, genotypic response to diverse agro-ecologies offers identification of strategic locations for evaluating traits of interest to strengthen and accelerate the national variety release program. In this study, multi-location field trial data have been used to investigate the impact of environmental conditions on crop phenological dynamics and their influence on the yield of mungbean in different agroecological regions of the Indian subcontinent. The present attempt is also intended to identify the strategic location(s) favoring higher yield and distinctiveness within mungbean genotypes. In the field trial, a total of 34 different mungbean genotypes were grown in 39 locations covering the north hill zone (n = 4), northeastern plain zone (n = 6), northwestern plain zone (n = 7), central zone (n = 11) and south zone (n = 11). The results revealed that the effect of the environment was prominent on both the phenological dynamics and productivity of the mungbean. Noticeable variations (expressed as coefficient of variation) were observed for the parameters of days to 50% flowering (13%), days to maturity (12%), reproductive period (21%), grain yield (33%), and 1000-grain weight (14%) across the environments. The genotype, environment, and genotype × environment accounted for 3.0, 54.2, and 29.7% of the total variation in mungbean yield, respectively (p < 0.001), suggesting an oversized significance of site-specific responses of the genotypes. Results demonstrated that a lower ambient temperature extended both flowering time and the crop period. Linear mixed model results revealed that the changes in phenological events (days to 50 % flowering, days to maturity, and reproductive period) with response to contrasting environments had no direct influence on crop yields (p > 0.05) for all the genotypes except PM 14-11. Results revealed that the south zone environment initiated early flowering and an extended reproductive period, thus sustaining yield with good seed size. While in low rainfall areas viz., Sriganganagar, New Delhi, Durgapura, and Sagar, the yield was comparatively low irrespective of genotypes. Correlation results and PCA indicated that rainfall during the crop season and relative humidity significantly and positively influenced grain yield. Hence, the present study suggests that the yield potential of mungbean is independent of crop phenological dynamics; rather, climatic variables like rainfall and relative humidity have considerable influence on yield. Further, HA-GGE biplot analysis identified Sagar, New Delhi, Sriganganagar, Durgapura, Warangal, Srinagar, Kanpur, and Mohanpur as the ideal testing environments, which demonstrated high efficiency in the selection of new genotypes with wider adaptability.

Prostaglandin E1-induced Catalepsy in the Rat: Role of Putative Neutrotransmitters

Prostaglandin E1 (PGE1) produced dose-related catalepsy in rats when administered intracerebroventricularly. PGE1 induced catalepsy was significantly inhibited after pretreatment with pharmacological agents known to attenuate central serotonergic and cholinergic activity. It was also inhibited by PGF2α and naloxone. On the contrary, treatments enhancing central dopaminergic activity also reduced the cataleptic effect of PGE1. The results suggest that PGE1 induces catalepsy in rats by modulating activity of central neurotransmitters.

Preoperative magnetic resonance spectroscopy improves diagnostic accuracy in a series of neurosurgical dilemmas

OBJECT

The purpose of this study was to evaluate the usefulness of preoperative magnetic resonance spectroscopy (MRS) in neurosurgical patients with diagnostically challenging intracranial lesions.

METHODS

Included in this study are twenty-three consecutive patients presenting to the neurosurgery service with diagnostically challenging intracranial lesions and who were investigated by conventional MR imaging and proton ((1)H) MRS, followed by surgery with subsequent histopathological diagnosis. An experienced neuroradiologist (RJ) blinded to the final histopathology evaluated the imaging studies retrospectively. Provisional diagnoses based on preoperative clinical and conventional MR data versus preoperative MRS data were compared with definitive histopathological diagnoses.

RESULTS

Compared with preoperative clinical and conventional MR data, (1)H MRS improved the accuracy of MR imaging from 60.9% to 83%. We found (1)H MRS reliably distinguished between abscess and high-grade tumour, and between high-grade glioma and low-grade glioma, but was not able to reliably distinguish between recurrent glioma and radiation necrosis. In 12/23 cases (52%) the (1)H MRS findings positively altered our clinical management. Two representative cases are presented.

CONCLUSIONS

Our study supports a beneficial role for (1)H MRS in certain diagnostic intracranial dilemmas presenting to neurosurgeons. The information gleaned from preoperative (1)H MRS can be a useful adjunct to clinical and conventional MR imaging data in guiding the management of patients with intracranial pathologies, particularly high-grade tumour versus abscess, and high-grade versus low-grade glioma. Further larger prospective studies are needed to clearly define the utility of (1)H MRS in diagnostically challenging intracranial lesions in neurosurgery.

Reaction of Dithiothreitol and Para-nitroacetophenone with Different Radical Precursors of .OH Radical-induced Strand Break Formation of Single-stranded DNA in Anoxic Aqueous Solution

The yields of single-strand breakage (ssb) in single-stranded calf thymus DNA (ssDNA) have been determined after 60Co gamma-irradiation of aqueous anoxic solutions in the presence of different concentrations of dithiothreitol (DTT), ascorbate or trans-4,5-dihydroxy-1,2-dithiane, using low-angle laser light scattering. The influence of DTT on the kinetics of ssb formation has been determined by conductivity measurements in pulse radiolysis. The results suggest that strand breakage in ssDNA proceeds via two modes of about equal contribution and with half-lives of about 7 ms and 0.8s, respectively. Both modes reflect reactions of at least two DNA radicals, which react with DTT by hydrogen-atom transfer reactions with similar rate constants of about 5-9 x 10(5) dm3 mol-1 s-1. These hydrogen-atom transfer reactions inhibit strand break formation. The slow mode is shown to represent the decay of base-radicals to generate sugar radicals. The involvement of the oxidizing .OH adduct radical of guanine in the formation of strand breaks can be ruled out and there is no evidence for a contribution from the anion or radical anion of DTT to the inhibition of strand breaks via electron transfer reactions to DNA radicals.

A Novel Insect Antifeedant Nonprotein Amino Acid from Calotropis gigantea

Giganticine (1), a novel nonprotein amino acid, has been isolated from a methanol extract of the root bark of Calotropis gigantea and its structure established by spectroscopic methods. It exhibited a significant antifeedant activity against nymphs of the desert locust Schistocerca gregaria.

Hierarchical gene diversity and genetic structure of tribal populations of Andhra Pradesh, India

Gene diversity and genetic structure of tribal populations of Andhra Pradesh, India, have been analyzed under a hierarchical model consisting of five regions of the state, tribes within the regions, and local subpopulations within the tribes. Average gene diversity has been estimated from gene frequency data for 15 polymorphic loci by using nested gene diversity analysis of GST. The intralocation coefficient of gene diversity was estimated at 96% of the total, whereas the intertribal, within--and between--regional gene diversities were found to be only 1.90, 0.95, and 1.43%, respectively. The estimate of gene diversity was higher for loci with higher degrees of polymorphism such as ABO, MN, ESD, and PTC and lower for loci with low-level polymorphism and extreme gene frequencies such as Hb, Tf, PHI, 6PGD, and Hp. The nature of selective preference or neutrality at the loci seems to be important in this respect. Tribes of the plains exhibit the least gene diversity, apparently because of higher gene flow among them. The contribution of loci with intermediate gene frequencies in intertribal and regional gene diversity was found to be higher than for loci with extreme allelic frequencies. These results suggest that the most significant component of variation is between individuals within locations and that variation between local subpopulations is negligible in the genetic structure of a population. Forces like selection, gene flow and drift also influence the diversity depending upon the nature of the locus.

Effect of centrally administered prostaglandin D2 and some prostaglandin synthesis inhibitors on carrageenan-induced paw oedema in rats

The putative modulatory role of central prostaglandins (PGs) on peripheral inflammation has been explored by investigating the effects of intracerebroventricularly (i.c.v.) administered PGD2, the major rodent brain PG, hydrocortisone, a phospholipase A2 inhibitor, and the cyclo-oxygenase inhibitors, paracetamol and mefenamic acid, on carrageenan-induced paw inflammation in rats. PGD2 produced a dose-related inflammation-augmenting effect, whereas hydrocortisone and the PG synthesis inhibitors, paracetamol and mefenamic acid, induced attenuation of the peripheral oedema. These findings confirm an earlier report from this laboratory which had indicated that central PGs may modulate peripheral inflammation and that conventional anti-inflammatory agents exert at least part of their effect by inhibiting central PG synthesis.

Brain monoamines during carrageenan-induced acute paw inflammation in rats

Paw inflammation was induced in rats by sub-plantar administration of carrageenan. Significant inflammatory oedema was observed 1 h later and the peak effect was noted between 3-4 h. The oedema was markedly reduced after 12-24 h. Steady state levels of whole brain and hypothalamic monoamines were estimated spectrofluorometrically during the course of the carrageenan-induced paw inflammation. In addition, the rate of accumulation of the brain 5-hydroxytryptamine (5-HT) and noradrenaline (NA) was assessed in clorgyline-pretreated rats during the inflammation. The whole brain and hypothalamic concentrations of 5-HT and NA were augmented during the early phase of the inflammation, but fell below control values when peak inflammation was achieved. Thereafter, the monoamine levels tended to normalize by 24 h when the inflammation had virtually subsided. On the contrary, whole brain and hypothalamic dopamine levels remained largely unaffected. The rate of accumulation of brain 5-HT and NA were enhanced during carrageenan inflammation, indicating that the turnover of these monoamines is augmented during the inflammatory process. The results suggest that acute peripheral inflammation may significantly affect central 5-HT and noradrenergic activity in rats.

Hyperthermic effect of centrally administered bradykinin in the rat: role of prostaglandins and serotonin

Intracerebroventricularly administered bradykinin (2.5, 5 and 10 micrograms/rat) produced a dose-related increase in the rectal temperature of adult Wistar strain albino rats. The bradykinin-induced hyperthermia was significantly attenuated following pretreatment of the animals with pharmacological agents which selectively reduce rat brain serotonin or prostaglandin (PG) activity. These findings, and those of earlier reports emanating from this laboratory which indicate that centrally administered bradykinin augments rat brain serotonin and PGE2 activity, suggest the involvement of PGs and serotonin in the hyperthermic action of bradykinin in this species.

Effect of pre-existing inflammation on carrageenan-induced paw oedema in rats

Twenty-four hours after injection of carrageenan into one hind paw, injection of the same amount into the contralateral paw produced a significantly attenuated inflammatory response. However, when the second injection was given 7 days later, the inflammation induced in the contralateral paw was comparable with the initial response to carrageenan. A time-course study of carrageenan-induced inflammation in rats showed that significant oedema persisted 24 h after carrageenan administration and complete recovery was achieved in 7 days. The attenuated inflammatory response in the contralateral paw after 24 h was antagonized by bilateral adrenalectomy and chemical sympathectomy induced by 6-hydroxydopamine. Carrageenan-induced paw oedema was also significantly less in rats with subacute inflammation induced by the croton oil granuloma pouch technique. This attenuated response was antagonized by pretreatment of the rats with metyrapone, an inhibitor of adrenocorticoid synthesis, and by 6-hydroxydopamine. It is likely that the pre-existing acute or subacute inflammation attenuates the inflammatory response of carrageenan, by acting as a stressor, inducing activation of the sympatho-adrenal system.

Prostaglandin D2-induced catalepsy in rats: role of 5-hydroxytryptamine

Prostaglandin D2 (PGD2), the major PG in the rat brain, induced a dose-related catalepsy in rats on intracerebroventricular (i.c.v.) administration. This cataleptic response was significantly attenuated following the i.c.v. administration of pharmacological agents that decrease rat brain 5-hydroxytryptamine (5-HT) activity. PGE1 synergized but PGF2 alpha antagonized the catalepsy induced by PGD2. PGD2 and PGE1 have previously been shown to augment rat brain 5-HT activity, whereas PGF alpha inhibited it. It is therefore likely that the observed effects of these PGs on catalepsy involve a central 5-HT mechanism.

Effects of intracerebroventricular administration of bradykinin on rat brain serotonin and prostaglandins

Intracerebroventricular (ICV) administration of bradykinin (5, 10 and 20 micrograms) produced a dose-related increase in the concentration of serotonin in rat brain. The maximum increase was observed after 15 min of bradykinin administration. Thereafter, the augmented levels of serotonin declined and tended to come to normal value after 60 min. Bradykinin (20 micrograms) significantly increased the concentrations of serotonin specifically in cortex, hypothalamus, midbrain and pons-medulla but not in cerebellum and spinal cord. The time course of increase and subsequent decline of regional concentrations of serotonin in brain were similar to that noted with bradykinin-induced changes in serotonin levels in whole brain. Bradykinin (5, 10 and 20 mg, ICV) increased the concentration of prostaglandin E2 (PGE2) but not of PGF2 alpha of rat brain. The time course of bradykinin-induced changes in PGE2 concentrations were similar to the effects of bradykinin on the levels of serotonin in rat brain. The inhibitors of PG synthesis, hydrocortisone, diclofenac and paracetamol, antagonized the bradykinin-induced increase of serotonin in rat brain. These results have provided support for the contention that PGs may presumably mediate some of the central actions of bradykinin and that bradykinin-induced augmentation of central serotonergic activity could possibly account for PGE2-induced modulation of rat brain serotonin.