Spectrophotometric Determination of Os(VIII) with Thioglycollic Acid

368-36

Effect of Diluents on the Extraction of Mercury(II) by n-Butyl Acetate

179-18

Spectrophotometric Investigation of Os(VI)- Thiocyanate Complex

291-29

A comparative study of three different methods of shoot meristem excision for induction of embryogenic calli in coconut

A protocol was standardized to maximize yields of embryogenic calli from shoot meristem culture of coconut. Three different shoot meristem excision methods were tested viz., excision of shoot meristem aseptically from in vitro germinated embryo after 10-12 days, excision of shoot meristem from in vitro germinated embryo subjected to GA3 treatment for five days and excision of shoot meristem from fresh embryo. The primary calli induction after 30 days of culture incubation for the three treatments were 21%, 27%  and 79% respectively.  Further, the primary calli formed from the shoot meristem excised from fresh embryo gave rise to 56% of embryogenic calli. The calli obtained from the shoot meristem which were excised from in vitro germinated embryo formed less percentage of embryogenic calli because of the presence of cotyledonary tissues which inhibited the multiplication of meristematic tissues. In the case of shoot meristem extracted from GA3-treated embryos, the percentage of non-embryogenic calli was more compared to the shoot meristem excised from fresh embryo. It was observed that the addition of GA3 in the initial stages of culture inhibited the formation of embryogenic calli and favored direct shoot development. Currently, the shoot meristem excised from fresh embryo is being employed for scaling up the planting material production from released varieties of coconut

Maintenance of embryogenic potential of calli derived from embryonic shoot of West Coast Tall cv. of coconut (Cocos nucifera L.)

Maintenance of embryogenic potential of calli is important as the totipotency is often lost in a short time in vitro. This caters to the need for year round availability of somatic embryos in a regenerable state. In the present study, 14 media combinations, with either 2,4-D or picloram as auxin source, were tested for maintaining embryogenic calli obtained from embryonic shoot explants of coconut. Irrespective of type and concentration of auxins, callusing was observed in all the media combinations. However, high dose of 2,4-D (above 74.6 μM) in the initial medium resulted in intense browning and lesser percentage of callusing. Embryogenic nature of calli could be maintained to a maximum of 21 weeks in medium supplemented with 2,4-D (74.6 μM) and subsequent culturing into higher concentration of 2,4-D (90.4 μM). Gene expression studies carried out using qRT-PCR revealed that genes such as ECP, GST, LEAFY and WUS were highly expressed in long term embryogenic calli (21 week old) and genes such as SERK, GLP, WRKY and PKL in initial embryogenic calli (21 days old). The study concludes that coconut plumular calli could be maintained for longer periods without compromising on the embryogenic potential of the calli

Initiation of coconut cell suspension culture from shoot meristem derived embryogenic calli: A preliminary study

An attempt was made to establish highly competent embryogenic cell suspension culture in coconut, a species recalcitrant to in vitro culture. Embryogenic calli were initiated from shoot meristem explants of coconut. Y3 medium supplemented with 2.4-D (4.5 μM) and glutamine (34.2 μM) was found to be the best medium to initiate cell suspension. Growth evaluation was done by packed cell volume (PCV) and it was found that maximum growth volume of 9.9% was reached at 200 days of culture initiation. About 52% of viable cells were detected through fluorescent microscopy. Cell aggregation was noticed in Y3 medium supplemented with glutamine (34.2 μM), malt extract (100mg/l), biotin (40.9 μM) and kinetin (9.3 μM), but further progress could not be achieved. It was also observed that embryogenic calli were not of a friable type, but were associated with densely aggregated cells. Because of its hard nature, we were unsuccessful to obtain high quality cell suspension

Studying vapor-liquid transition using a generalized ensemble

Homogeneous vapor-liquid nucleation is studied using the generalized Replica Exchange Method (gREM). The generalized ensemble allows the study of unstable states that cannot directly be studied in the canonical ensemble. Along with replica exchange, this allows for efficient sampling of the multiple states in a single simulation. Statistical Temperature Weighted Histogram Analysis Method is used for postprocessing to get a continuous free energy curve from bulk vapor to bulk liquid. gREM allows the study of planar, cylindrical, and spherical interfaces in a single simulation. The excess Gibbs free energy for the formation of a spherical liquid droplet in vapor for a Lennard-Jones system is calculated from the free energy curve and compared against the umbrella sampling results. The nucleation free energy barrier obtained from gREM is then used to calculate the nucleation rate without relying on any classification scheme for separating the vapor and liquid

Detrimental effects of tropisetron on permanent ischemic stroke in the rat

<p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence indicates that blockade of 5-hydroxytryptamine (5-HT) receptor 3 (5-HT₃) is able to confer protection in different models of neuronal injury. The purpose of the present study was to investigate the effect of tropisetron, a 5-HT₃receptor antagonist, on infarct size and neurological score in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in the rat.</p> <p>Methods</p> <p>Two different doses of tropisetron (5 and 10 mg/kg) or vehicle were administered intraperitoneally 30 min before pMCAO. Neurological deficit scores, mortality rate and infarct volume were determined 24 h after permanent focal cerebral ischemia.</p> <p>Results</p> <p>Tropisetron failed to reduce cerebral infarction. Animals receiving tropisetron showed a significant increase (p < 0.05) in neurological deficits and mortality rate.</p> <p>Conclusion</p> <p>Data from this study indicate that blockade of 5-HT₃receptors with tropisetron worsens ischemic brain injury induced by pMCAO. These findings could have important clinical implications. Patients taking tropisetron, and possibly other 5-HT₃antagonists, could potentially have a worse outcome following a brain infarct.</p