The use of alternative fuels for the mitigation of ecological impacts by use of diesel has been focus of intensive research. In the present work, algal oils extracted from cultivated biomass of Cladophora sp., Spirogyra sp. and Oedogonium sp. were evaluated for the lipase-mediated synthesis of fatty acid monoalkyl esters (FAME, biodiesel). To optimize the transesterification of these oils, different parameters such as the alkyl group donor, reaction temperature, stirring time and oil to alcohol ratio were investigated. Four different alcohols i.e. methanol, ethanol, n-propanol and n-butanol were tested as alkyl group donor for the biosynthesis FAME and methanol was found to be the best. Similarly, temperature 50 C and stirring time of 6 h were optimized for the transesterification of oils with methanol. The maximum biodiesel conversions from Cladophora (75.0%), Spirogyra (87.5%) and Oedogonium (92.0%) were obtained when oil to alcohol ratio was 1: 8. 相似文献
Two populations, one from lesser saline Derawar Fort (DF) and the other from highly saline Ladam Sir (LS) in the Cholistan
desert, for each of the five grass species, Aeluropus lagopoides, Cymbopogon jwarancusa, Lasiurus scindicus, Ochthochloa compressa, and Sporobolus ioclados were examined to investigate the influence of salinity on structural and functional characteristics of stomata. Salinity
tolerance in A. lagopoides mainly depended on controlled transpiration rate (E) and high water-use efficiency (WUE), which was found to be regulated by fewer and smaller stomata on both leaf surfaces
as well as stomatal encryption by epidermal invaginations. C. jwarancusa had sunken stomata on the abaxial surface only, which largely reflected a reduced E, but less affected stomatal conductance (gs) or WUE. L. scindicus had fewer but larger stomata along with hairs/trichomes which may function to avoid water loss through transpiration, and
hence, to attain a high WUE. In O. compressa stomata were found only on the abaxial surface and these were completely encrypted by epidermal invaginations as well as
a dense covering of microhairs, which was associated with a low E and high WUE under salinity stress. In S. ioclados, the traits of increased stomatal density and decreased stomatal area may be critical for stomatal regulation under salt-prone
environments. High stomatal regulation depended largely on stomatal density, area, and degree of encryption under salinity,
which is of great ecophysiological significance for plants growing under osmotic stresses. 相似文献
Macrobrachium rosenbergii was experimentally challenged with Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) to study the clearance of these viruses and consequent changes in various immunological parameters. The healthy animals were injected MrNV and XSV intramuscularly and various organ samples such as gill tissue, head soft tissue, pleopods and intestine were collected at different time intervals of 3, 5, 10, 15, 25, 50, 75 and 100 d post-infection (p.i.) to study the viral clearance. Tissue tropism and clearing of MrNV and XSV were confirmed by RT-PCR, nested RT-PCR and bioassay. These 2 viruses failed to cause mortality or clinical signs of disease in injected adult prawns during the experimental period of 100 days. The result of RT-PCR analysis revealed that all the organs showed positive for both viruses by single step RT-PCR on 3, 5 and 10 d p.i., positive by nested RT-PCR on 15 and 20 d p.i. and all the organs became negative at 25 d p.i. onwards. The viral inoculum prepared from the tissue of MrNV and XSV-injected M. rosenbergii at 3, 5, 10, 15 and 20 d p.i. caused 100% mortality in post-larvae of M. rosenbergii at 9, 8, 7, 10 and 10 d p.i., respectively whereas the inoculum prepared at 25, 50 and 100 d p.i. failed to cause significant mortality in post-larvae of prawn. Immunological parameters such as proPO, superoxide anion, SOD, THC, clotting time and oxyhemocyanin were determined in MrNV and XSV-injected prawns and significant differences in some of the immunological parameters were found in the early days p.i. and became insignificant in the later days p.i. 相似文献
Two chromium-resistant bacterial strains, Bacillus cereus S-6 and Ochrobactrum intermedium CrT-1, and two cyanobacterial strains, Oscillatoria sp. and Synechocystis sp., were used in this study. At initial chromate concentrations of 300 and 600 μg K2CrO4 mL−1, and an inoculum size of 9.6×107 cells mL−1, B. cereus S-6 completely reduced Cr(VI), while O. intermedium CrT-1 reduced Cr(VI) by 98% and 70%, respectively after 96 h. At 100 μg K2CrO4 mL−1, Synechocystis sp. MK(S) and Oscillatoria sp. BJ2 reduced 62.1% and 39.9% of Cr(VI), respectively, at 30°C and pH 8. Application of hexavalent chromate salts adversely affected wheat seedling growth and anatomical characters. However, bacterial inoculation alleviated the toxic effects, as reflected by significant improvements in growth as well as anatomical parameters. Cyanobacterial strains also led to some enhancement of various growth parameters in wheat seedlings.
Atrial myocytes that lack t-tubules appear to have two functionally separate sarcoplasmic Ca2+ stores: a peripheral store associated with plasmalemmal L-type calcium channels and a central store with no apparent proximity to L-type calcium channels. Here we describe a set of calcium sparks and waves that are triggered by puffing of pressurized (200-400 mmH2O) bathing solutions onto resting isolated rat atrial myocytes. Puffing of pressurized (200 mmH2O) solutions, identical to those bathing the myocytes from distances of approximately 150 microm onto the surface of a single myocyte triggered or enhanced spontaneously occurring peripheral sparks by five- to six-fold and central Ca2+ sparks by two- to three-fold, without altering the unitary spark properties. Exposure to higher pressure flows (400 mmH2O) often triggered longitudinally spreading Ca2+ waves. These results suggest that pressurized flows may directly modulate Ca2+ signaling of atrial myocytes by activating the intracellular Ca2+ release sites. 相似文献
Ingestion of aqueous 70% ethanol extract of Ballota nigra (400 mg/kg body weight for 7 days) by albino rats (n=10) was investigated to study its effects on glucose, total cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotransferase (ALT), troponin I (TnI), serum creatine kinase (CK), total protein, total bilirubin and blood urea. Ballota nigra extract caused a significant decrease in blood glucose, total serum cholesterol and CK levels. Blood levels of TnI, AST, ALT, triglycerides, total bilirubin, total protein and blood urea were unchanged. The hypoglycemic effect of Ballota nigra extract on albino rats was further investigated by conducting a glucose tolerance test intraperitoneally (IPGTT). Healthy rats that were fasting for 18 hours followed by administration of a dose of 400 mg/kg body weight of the crude extract of Ballota nigra, orally. A significant decrease in blood glucose levels (after 15, 30, and 45 minutes) with a significant increase in serum insulin level (after 15 and 30 minute) was noted. These results suggest that, the crude extract of Ballota nigra have hypoglycemic, insulin-releasing and cholesterol lowering effects in rats. 相似文献
The effects of long-term ingestion of fluoxetine on fertility were investigated in Sprague-Dawley male rats. Adult male rats were exposed to fluoxetine at a concentration of 200 mg/kg for 60 days. Long-term ingestion of fluoxetine for 60 days caused a great decrease in spermatogenesis in seminiferous tubules of the testes. Sperm motility and density were also significantly reduced in cauda epididymides and testes of the treated group. The weights of reproductive organs (testes, epididymides, ventral prostrate and seminal vesicle) were decreased considerably. The hormonal assay also showed significant decrease in testosterone levels and FSH levels. Testicular cell population dynamics also demonstrated a decrease in the number of both primary and secondary spermatocystes and spermatids in the treatment group. The number of female rats impregnated by male rats on long-term fluoxetine diet had decreased. The number of implantations and the number of viable fetuses were also notably decreased in female rats impregnated by male rats ingested fluoxetine. Fluoxetine caused a slight decrease in body weight, when initial and final body weights were compared in the experimental groups. Levels of ALT and AST were found to be significantly increased in the treated group when compared to the control. Histometery of reproductive organs confirmed these results. In conclusion, these results confirm that the long-term fluoxetine ingestion produce adverse effects on fertility and reproductive system in adult male rat. Thus, it would be of great interest to investigate the impact via long -term treatment with fluoxetine in male human fertility. 相似文献
Early (E9.5-E11.5) embryonic heart cells beat spontaneously, even though the adult pacemaking mechanisms are not yet fully established. Here we show that in isolated murine early embryonic cardiomyocytes periodic oscillations of cytosolic Ca(2+) occur and that these induce contractions. The Ca(2+) oscillations originate from the sarcoplasmic reticulum and are dependent on the IP(3) and the ryanodine receptor. The Ca(2+) oscillations activate the Na(+)-Ca(2+) exchanger, giving rise to subthreshold depolarizations of the membrane potential and/or action potentials. Although early embryonic heart cells are voltage-independent Ca(2+) oscillators, the generation of action potentials provides synchronization of the electrical and mechanical signals. Thus, Ca(2+) oscillations pace early embryonic heart cells and the ensuing activation of the Na(+)-Ca(2+) exchanger evokes small membrane depolarizations or action potentials. 相似文献