Markov Systematic Sampling

In this paper, a new systematic sampling scheme with Markovian behaviour which yields positive first order inclusion probabilities for all units and positive second order inclusion probabilities for all pairs of units is introduced. The suggested method has been compared with sample random sampling, stratified random sampling, linear systematic sampling and systematic sampling with two random starts for the populations exhibiting exponential trend, autocorrelatedness and randomness. Throughout the discussion, the sample size is assumed to be even and the population size is a multiple of the sample size. The suggested method works well for estimating a finite population total for the population exhibiting exponential trend.     

Differential induction, purification and characterization of cold active lipase from Yarrowia lipolytica NCIM 3639

The production, purification and characterization of cold active lipases by Yarrowia lipolytica NCIM 3639 is described. The study presents a new finding of production of cell bound and extracellular lipase activities depending upon the substrate used for growth. The strain produced cell bound and extracellular lipase activity when grown on olive oil and Tween 80, respectively. The organism grew profusely at 20 °C and at initial pH of 5.5, producing maximum extracellular lipase. The purified lipase has a molecular mass of 400 kDa having 20 subunits forming a multimeric native protein. Further the enzyme displayed an optimum pH of 5.0 and optimum temperature of 25 °C. Peptide mass finger printing reveled that some peptides showed homologues sequence (42%) to Yarrowia lipolytica LIP8p. The studies on hydrolysis of racemic lavandulyl acetate revealed that extracellular and cell bound lipases show preference over the opposite antipodes of irregular monoterpene, lavandulyl acetate.     

Effects of Nerve Growth Factor on Glutathione Peroxidase and Catalase in PC 12 Cells

Abstract: Nerve growth factor (NGF) is a member of the neuro- trophin family and is required for the survival and maintenance of peripheral sympathetic and sensory ganglia. In the CNS, NGF regulates cholinergic expression by basal forebrain cholinergic neurons. NGF also stimulates cellular resistance to oxidative stress in the PC12 cell line and protects PC12 cells from the toxic effects of reactive oxygen species. The hypothesis that NGF protection involves changes in antioxidant enzyme expression was tested by measuring its effects on catalase and glutathione per- oxidase (GSH Px) mRNA expression in PC12 cells. NGF increased catalase and GSH Px mRNA levels in PC 12 cells in a time- and dose-dependent manner. There was also a corresponding increase in the enzyme activities of catalase and GSH Px. Thus, NGF can provide cytoprotection to PC12 cells by inducing the free radical scavenging enzymes catalase and GSH Px.     

Adventitious shoot formation in decapitated dicotyledonous seedlings starts with regeneration of abnormal leaves from cells not located in a shoot apical meristem

Regeneration of new shoots in plant tissue culture is often associated with appearance of abnormally shaped leaves. We used the adventitious shoot regeneration response induced by decapitation (removal of all preformed shoot apical meristems, leaving a single cotyledon) of greenhouse-grown cotyledon-stage seedlings to test the hypothesis that such abnormal leaf formation is a normal regeneration progression following wounding and is not conditioned by tissue culture. To understand why shoot regeneration starts with defective organogenesis, the regeneration response was characterized by morphology and scanning electron and light microscopy in decapitated cotyledon-stage Cucurbita pepo seedlings. Several leaf primordia were observed to regenerate prior to differentiation of a de novo shoot apical meristem from dividing cells on the wound surface. Early regenerating primordia have a greatly distorted structure with dramatically altered dorsoventrality. Aberrant leaf morphogenesis in C. pepo gradually disappears as leaves eventually originate from a de novo adventitious shoot apical meristem, recovering normal phyllotaxis. Similarly, following comparable decapitation of seedlings from a number of families (Chenopodiaceae, Compositae, Convolvulaceae, Cucurbitaceae, Cruciferae, Fabaceae, Malvaceae, Papaveraceae, and Solanaceae) of several dicotyledonous clades (Ranunculales, Caryophyllales, Asterids, and Rosids), stems are regenerated bearing abnormal leaves; the normal leaf shape is gradually recovered. Some of the transient leaf developmental defects observed are similar to responses to mutations in leaf shape or shoot apical meristem function. Many species temporarily express this leaf development pathway, which is manifest in exceptional circumstances such as during recovery from excision of all preformed shoot meristems of a seedling.     

Syringeal anatomy and allometry in murres (Alcidae: Uria)

Species and sexual differences in vocalizations and the vocal tract are widespread. We studied the vocal tract of Common (Uria aalge) and Thick-billed (U. lomvia) Murres. We predicted anatomical or allometric differences in adults between species and sexes due to vocal differences related to social behavior (Common Murres nest at higher densities; males are the more aggressive sex, etc.). The vocal tract was anatomically simple and similar between species and sexes. The trachea was mainly cartilage, but the posteriormost 4–6 tracheal rings were calcified and fused as the tympanum, as part of the syrinx. The syrinx included the (unfused) first bronchial semirings, which were enlarged and calcified beneath the insertion of M. tracheolateralis. Weak bilateral asymmetry (right side larger) occurred in widths of M. tracheolateralis and M. sternotrachealis. The trachea was ∼10% longer in Common Murres; the tympanum and M. sternotrachealis width were relatively larger in Thick-billed Murres. Vocal-tract morphology and size did not differ between the sexes in either species. In allometric analyses on adults, isometry characterized (1) tympanum size in relation to head + bill length, and to humerus length (respectively), in Thick-billed Murres, and (2) M. sternotrachealis width in relation to tarsometatarsal length in both species. Comparative field studies on species and sexes are needed to clarify the functional significance of our findings in relation to vocalization.     

Effect of deacetylation time on the preparation, properties and swelling behavior of chitosan films

The objectives of the study were to propose a two-stage microfluidization combined with an ultrafiltration (UF) treatment for chitosan mass production and the manipulation of molecular weight and its distribution. The proposed methods are based on the degradation rate and rate constant of various process variables studied. Results obtained were that the rate constants were faster during the earlier reaction period, were higher for those operating at a higher pressure, were better for using concurrent UF treatment to remove small degraded fragments, and the degradation rate constants were faster for 30 °C solutions than that for 50 or 0 °C. A two-stage microfluidization process is proposed. The first stage constitutes of the highest possible concentration solution with concurrent UF treatment at 50 °C, and recycled 5 times. The second stage consists of the highest possible concentration of solutions with concurrent UF treatment at 30 °C, and recycled 5 times.     

The differential stability of the left and right domains of papain

We have investigated the differential stability of the two domains of papain, a broad specific cysteine protease, which is one of the most commonly used enzyme in various industries. The denaturant induced equilibrium unfolding of this enzyme has been investigated by different spectroscopic techniques. By site specific fluorescent labeling of one of the domain, we observed that during the unfolding process, L domain unfolds first and the R domain unfolds at a later stage. Spectroscopic studies reveal a biphasic unfolding transition, suggesting the presence of an intermediate during the unfolding process. The intermediate is observed between 1.5 and 2.5 M GuHCl and between 3 and 5 M in the case of urea induced unfolding. The unfolding process for both native to intermediate and intermediate to unfolded species is reversible in the case of urea unfolding, with a ΔG of ?2.4 and ?5.5 kcal/mole respectively where as for GuHCl unfolding only native to intermediate species is reversible indicating the predominance of hydrophobic interactions in the stability of the molecule.