Thermal Manipulation of Gold Nanocomposites for Microfluidic Platform Optimization

Plasmonics - Surface gold–polymer nanocomposites are prepared by using the thermal convection method for the deposition of gold colloids onto the surface of four polymer films: poly(-vinyl...     

Sex-specific changes in platelet aggregation and secretion with sexual maturity in pigs.

Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2-3 mo) and sexually mature (adult; 5-6 mo) male and female pigs (n=8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 microM) and collagen (6 microg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet fibrinogen receptor, P-selectin expression, and receptors for sex steroids did not change with sexual maturation. Plasma C-reactive protein and brain-type natriuretic peptide also did not change. Results indicate that changes in platelet aggregation and secretion change with sexual maturity differently in females and males. These observations provide evidence on which clinical studies could be designed to examine platelet characteristics in human children and young adults.     

Influence of carbon and nitrogen sources on glutathione catabolic enzymes inCandida albicans during dimorphism

The effect of carbon sources, glucose and sucrose, and nitrogen sources such as ammonia, glutamate andl-citrulline on the activities of glutathione metabolic enzymes has been studied. Yeast and mycelial cells were used to identify changes in activity levels of glutathione reductase (GSSGR), glutathione transferase (GST), glutathione peroxidase (GPX) and -glutamyl transpeptidase (GGT). Enzyme activities from cells grown in sucrose media were lower than in glucose media regardless of the enzyme tested, morphological form, or the growth interval. In all enzymes except GST, activity was higher in yeast form than in mycelia, regardless of nitrogen source, with lower activity from 24 to 72 h than at 96 h. In citrulline media, yeast form showed the maximum GST, GGT, and GPX activity. In ammonia-amended media, mycelia showed maximum activity in GGT, whereas in glutamate media, mycelia showed the maximum activity in GST. Also, the type of nitrogen source had no effect on GPX activity in the mycelial form. Finally, changing the nitrogen source showed no significant effect on GSSGR activity, either in the yeast or mycelial form.     

Recipes for reconstituting skin

Reconstituted Living Skin Equivalent (LSE) is made up of a dermal equivalent (DE) on which keratinocytes are plated where they give rise to a multilayered differentiated epidermis. The dermal equivalent develops through interactions between fibroblasts and collagen fibrils that begin to form after the cell-matrix precursor is cast. The gel that forms as a result of collagen polymerization and fluid trapping is contracted uniformly in all dimensions. By securing it at ends and edges in the mold in which it is cast, the final dimensions, strength and morphology of the forming tissue are altered. The same phenomena are seen in casting tubular tissues for the fabrication of small caliber blood vessel equivalents. The cells of the dermal equivalent are biosynthetically active and enrich the matrix to different degrees with secretory products, depending on how the cells are stimulated and on the presence or absence of an epidermis. Collagen biosynthesis by dermal cells in the DE is sensitive to growth factors, ascorbate concentrations and amino acid pools. Both ascorbate and TGF beta 1 increase total collagen biosynthesis at least two-fold by one week after tissue formation. With TGF beta 1 present, the capacity of cells in the DE to synthesize collagen increases with time, over a two-week period. If ascorbate (200 micrograms/ml) is added just after the tissue is cast and daily thereafter, contraction lattice is blocked, and collagen biosynthesis is enhanced relative to contracted controls that had received 200 micrograms/ml ascorbate once. The increase was nearly an order of magnitude over that of controls and was coordinate with a comparable increase in hyaluronate and sulfated glycosaminoglycan (GAG) production as shown by TCA-precipitable glucosamine in the intercellular matrix of the DE. Both the LSE and the Living Dermal Equivalent (LDE) exhibit complex responses to UV radiation and to various chemicals that are greatly different from responses given by monolayered cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

N-terminal Pro-Brain Natriuretic Peptide And Atrial Fibrillation

NT-proBNP is produced from both atria and ventricles. The primary regulation of production is at the synthesis level. The plasma half-life of NT-proBNP is 60-120 min. Cutoff value of NT-proBNP for diagnosis of heart failure is 125 pg/ml in the age group below 75 years and 450 pg/ml in the age group above 75 years. It increases in atrial fibrillation and drops after successful cardioversion. High levels predict development of atrial fibrillation (AF) in healthy persons with sinus rhythm (SR). Some studies concluded that baseline level predicts maintenance of SR after cardioversion of AF while some others found that it did not. Many studies have proven that it is useful in monitoring rhythm stability after cardioversion of AF. Since it is increased in many other conditions, out of which some may also cause AF, care must be taken before ascribing changes in its level to AF alone.     

Resistance in hybrid derivatives of Lycopersicon accessions against leaf caterpillar, Spodoptera litura Fab.

Four tomato accessions, namely Ac 238, Roma, Seijima Jeisei and Varushanadu Local selected from preliminary screening of 321 accessions and their hybrid derivatives, namely HY₁F₁ (Varushanadu Local × Ac 238), HY₂F₁ (Varushanadu Local × Roma), HY₃F₁ (Ac 238 × Roma) (first generation), HY₁F₂, HY₂F₂ and HY₃F₂ (second generation) were evaluated for their resistance in comparison with a susceptible check, 1979 against the leaf caterpillar, Spodoptera litura Fab. both under field and laboratory conditions at Annamalainagar, Tamil Nadu, India. In the field evaluation, accession Seijima Jeisei and hybrid HY3F1 recorded the minimum larval population. In glasshouse and laboratory studies, Seijima Jeisei was the least preferred by S. litura for both feeding and oviposition. The hybrid HY₃F₁ exerted pronounced antibiosis effect on S. litura. Among the various biophysical and biochemical bases of resistance, contents of reducing sugar and phenol were found negatively correlated with S. litura larval feeding. Among the hybrids, HY₃F₁ and HY3F2 and the parent Seijima Jeisei recorded higher fruit yield per plant in both seasons. Considerable variation in the resistance traits of the hybrids was observed when compared with the parents.     

Preliminary characterization of exopolysaccharides produced by a marine biofilm-forming bacterium Pseudoalteromonas ruthenica (SBT 033)

AIM: The major objective of the present study was the partial characterization of the exopolysaccharides (EPS) produced by a marine biofilm-forming bacterium Pseudoalteromonas ruthenica under shake culture conditions. METHODS AND RESULTS: EPS-producing bacterial cultures were isolated from the sea water collected from the vicinity of coastal electric power station. Zobell marine broth medium was used for growth of the cultures and the EPS produced was quantified using phenol sulfuric acid method. Chemical characterization of the EPS was carried out using Fourier transform infrared spectroscopy (FTIR), and capillary gas chromatography (GC). Further, viscosity and rheological properties of the purified EPS were studied. The FTIR spectrum revealed prominent peaks of various groups of OH and CH(3) bending. GC analysis showed the presence of eight individual sugars. Rheological studies of the aqueous EPS showed good shearing property. CONCLUSIONS: Pseudoalteromonas ruthenica isolated from marine environment produced copious amount of EPS under shake culture conditions. GC analysis of the EPS revealed the presence of eight individual sugars and the EPS had good shearing property. SIGNIFICANCE AND IMPACT OF THE STUDY: The EPS produced by P. ruthenica is pseudoplastic in nature and is stable at higher pH levels. These properties suggest that the EPS may have potential applications in the oil, textiles and food industries.     

The influence of sample preparation and replicate analyses on HeLa Cell phosphoproteome coverage

Ongoing optimization of proteomic methodologies seeks to improve both the coverage and confidence of protein identifications. The optimization of sample preparation, inclusion of technical replicates (repeated instrumental analysis of the same sample), and biological replicates (multiple individual samples) are crucial in proteomic studies to avoid the pitfalls associated with single point analysis and under-sampling. Phosphopeptides were isolated from HeLa cells and analyzed by nano-reversed phase liquid chromatography electrospray ionization tandem mass spectrometry (nano-RP-LC-MS/MS). We observed that a detergent-based protein extraction approach, followed with additional steps for nucleic acid removal, provided a simple alternative to the broadly used Trizol extraction. The evaluation of four technical replicates demonstrated measurement reproducibility with low percent variance in peptide responses at approximately 3%, where additional peptide identifications were made with each added technical replicate. The inclusion of six technical replicates for moderately complex protein extracts (approximately 4000 uniquely identified peptides per data set) affords the optimal collection of peptide information.