Direct somatic embryogenesis and plantlet regeneration from seedling leaves of winged bean,Psophocarpus tetragonolobus (L.) DC

Excised seedling leaf segments of winged bean [Psophocarpus tetragonolobus (L.) DC.] underwent direct somatic embryogenesis under appropriate incubation conditions. Initiation and development of the somatic embryos occurred using a two-step culture method. The culture procedure involved incubation for 28 days on MS basal medium supplemented with 0.1–0.5 mg/l NAA and 1.0–2.0 mg/l BA (induction medium) before transfer to MS medium supplemented with 0.1 mg/l IAA and 2.0 mg/l BA (embryo development medium). The initial exposure to low levels of NAA coincident with high levels of BA in the induction medium was essential for embryogenic induction. Maximum embryogenesis (43.3%) was obtained with 0.2 mg/l NAA and 2.0 mg/l BA, and at least 14 days on induction medium were required prior to transfer to the embryo development medium. The conversion frequency of cotyledonary embryos was 53.3% upon culture on MS medium containing 0.1 mg/l ABA for 7 days followed by transfer to MS medium supplemented with 0.1 mg/l IBA and 0.2 mg/l BA. Following conversion, the regenerated plantlets were transferred to soil and showed normal morphological characteristics.Abbreviations MS Murashige and Skoog (1962) medium - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - BA 6-benzylaminopurine - ABA abscisic acid     

The design and synthesis of human branched-chain amino acid aminotransferase inhibitors for treatment of neurodegenerative diseases

The inhibition of the cytosolic isoenzyme BCAT that is expressed specifically in neuronal tissue is likely to be useful for the treatment of neurodegenerative and other neurological disorders where glutamatergic mechanisms are implicated. Compound 2 exhibited an IC50 of 0.8 microM in the hBCATc assays; it is an active and selective inhibitor. Inhibitor 2 also blocked calcium influx into neuronal cells following inhibition of glutamate uptake, and demonstrated neuroprotective efficacy in vivo. SAR, pharmacology, and the crystal structure of hBCATc with inhibitor 2 are described.     

Evaluation of antioxidant properties of root bark of Hemidesmus indicus R. Br. (Anantmul).

Hemidesmus indicus R. Br. (Asclepiadaceae) is a well known drug in Ayurveda system of medicine. In the present study, antioxidant activity of methanolic extract of H. indicus root bark was evaluated in several in vitro and ex vivo models. Further, preliminary phytochemical analysis and TLC fingerprint profile of the extract was established to characterize the extract which showed antioxidant properties. The in vitro and ex vivo antioxidant potential of root bark of H. indicus was evaluated in different systems viz. radical scavenging activity by DPPH reduction, superoxide radical scavenging activity in riboflavin/light/NBT system, nitric oxide (NO) radical scavenging activity in sodium nitroprusside/Greiss reagent system and inhibition of lipid peroxidation induced by iron-ADP-ascorbate in liver homogenate and phenylhydrazine induced haemolysis in erythrocyte membrane stabilization study. The extract was found to have different levels of antioxidant properties in the models tested. In scavenging DPPH and superoxide radicals, its activity was intense (EC50 = 18.87 and 19.9 microg/ml respectively) while in scavenging NO radical, it was moderate. It also inhibited lipid peroxidation of liver homogenate (EC50 = 43.8 microg/ml) and the haemolysis induced by phenylhydrazine (EC50 = 9.74 microg/ml) confirming the membrane stabilization activity. The free radical scavenging property may be one of the mechanisms by which this drug is effective in several free radical mediated disease conditions.     

Uridine 5′-diphosphate glucose 4-epimerase from ehrlich ascites carcinoma cells

Uridine 5′-diphosphate glucose 4-epimerase (EC 5.1.3.2) from Ehrlich ascites carcinoma cells was purified to apparent homogeneity using conventional procedures and NAD-hexane-agarose affinity chromatography. The protein had a molecular weight of 96,000. The ascites enzyme had an absolute requirement for exogenously added NAD (10 ΜM) for stability. This appears to be a unique feature of ascites epimerase since epimerase from other mammalian sources did not exhibit such a dependence. Exogenously added NAD was also needed for catalysis with an apparentK _m value of 2.5 ΜM. NADH was a very potent competitive inhibitor (K _i = 0.11 ΜM with respect to NAD) of the enzyme activity at pH values close to intracellular pH. The dependence of the enzyme on NAD for stability and its inhibition by NADH may have some potential significance in tumor metabolism     

Development of a simple sperm cryopreservation model using a chemically defined medium and goat cauda epididymal spermatozoa

This investigation was carried out to develop a simple sperm cryopreservation model using a chemically defined synthetic medium (modified Ringer's solution) and mature goat cauda epididymal sperm as the model system. Rates of cooling, freezing, and maximum freezing temperature were manipulated with the help of a computer-controlled programmable biofreezer. Highly motile goat cauda sperm dispersed in a modified Ringer's solution was subjected to the freezing protocol: cooling 0.25 degrees C min(-1) to 5 degrees C, 5 degrees C min (-1) to -20 degrees C, 20 degrees C min(-1) to -100 degrees C, prior to plunging into liquid nitrogen. In the absence of any cryoprotective agent, all of the spermatozoa lost their motility. Addition of glycerol (0.22 to 0.87 M) caused a dose-dependent increase of sperm motility recovery. The highest recovery of forward and total motility was (32 and 35%, respectively) at 0.87 M. Further increase of the glycerol concentration caused a marked decrease in motility. Changes in the cooling rate particularly before and during freezing had a notable effect on the sperm motility recovery. There was no or low recovery (0-18%) of sperm motility when the cells were transferred directly to liquid nitrogen from the initial two cooling stages. The data demonstrate the importance of all of the cooling stages in the cryopreservation of the cells. Like glycerol, dimethyl sulfoxide (Me(2)SO) and ethylene glycol also showed a dose-dependent increase in motility recovery as well as a biphasic curve of cryoprotection. At optimal concentrations, dimethyl sulfoxide (1.00 M) and ethylene glycol (1.29 M) were effective in recovering sperm motility to the extent of 20 and 13%, respectively. Thus these reagents have markedly lower cryoprotection potential than glycerol.     

Hypobaric hypoxia modulates brain biogenic amines and disturbs sleep architecture

Sojourners to high altitude experience poor-quality of sleep due to hypobaric hypoxia (HH). Brain neurotransmitters are the key regulators of sleep wakefulness. Scientific literature has limited information on the role of brain neurotransmitters involved in sleep disturbance in HH. The present study aimed to investigate the time dependent changes in neurotransmitter levels and enzymes involved in the biosynthesis of brain neurotransmitters in frontal cortex, brain stem, cerebellum, pons and medulla and the effect of these alterations on sleep architecture in HH. Thirty adult Sprague-Dawley rats, body weight of 230-250 g were exposed to simulated altitude ～7620 m, 282 mm Hg, partial pressure of O(2) 59 mm Hg for 7 and 14 days continuously in an animal decompression chamber. After 7 and 14 days of HH, brain nor-epinephrine and dopamine levels were significantly increased in frontal cortex, brain stem, cerebellum and pons and medulla whereas serotonin level was significantly reduced in frontal cortex and pons and medulla after 14 days of HH. Tyrosine hydroxylase level in locus coeruleus (LC) was significantly increased whereas Choline Acetyl Transferase and Glutamic Acid Decarboxylase (GAD) levels were significantly reduced in laterodorsal-tegmentum and pedunculopontine-tegmentum after 7 days of HH. GAD was also reduced in LC after 7 days HH. Alteration in these neurotransmitters and enzyme levels was accompanied with reduction in quality and quantity of sleep. There was a significant increase in sleep latency, rapid eye movement (REM) latency, duration of active awake, quiet awake, quiet sleep and a significant decrease in duration of REM sleep and deep sleep on day 7 and 14 of HH. It was concluded that HH alters the expression of enzymes linked to sleep neurotransmitter synthesis pathway and subsequent loss of homeostasis at neurotransmitter level disrupts the sleep pattern in hypobaric hypoxia.