Investigating the antimicrobial,antioxidant and cytotoxic activities of the biological synthesized glutathione selenium nano-incorporation

BioMetals - Aqueous glutathione selenium nano-incorporation (GSH-SeN-Inco) was prepared by gamma radiation in presence of microbial glutathione (GSH) and selenium dioxide. The novel prepared...     

Spirulina platensis extract addition to semen extender enhances cryotolerance and fertilizing potentials of buffalo bull spermatozoa

The objective of this study was to investigate the effect of Spirulina platensis extract (SPE) addition to the freezing extender on freezability, lipid peroxidation, ultrastructure alterations and fertilizing potentials of frozen-thawed buffalo bull spermatozoa. Semen samples were collected with artificial vagina from five adult fertile bulls and diluted with Tris-base extender containing SPE (1, 5, 10 and 20 μg/mL) or without SPE (control). Diluted semen was cooled to 4 °C throughout one hour and frozen in 0.25 mL straws: prior to being stored in liquid nitrogen. Cryopresreved spermatozoa were assessed for post-thawing sperm motility, viability, acrosomal integrity, ultrastructure changes, antioxidant activities, lipid peroxidation and fertility rate. The current results clearly indicated that adding 10μg/mL SPE to the freezing extender significantly improved (P< 0.05) post-thawing motility and decrease the percentage of acrosomal damage (51.67±6.02% and 16.33±1.46%, respectively) compared with the control (28.33±4.41% and 26.33±1.77%, respectively). Moreover, addition of 10 μg/mL SPE to the semen extender significantly diminished (P< 0.05) MDA concentration (10.66±2.40 nmol/10⁹) compared with the control (22.66±4.26 nmol/10⁹). Therefore, the present results revealed that addition of 10μgl/mL SPE to the freezing extender might improve semen quality and reduce cryodamage of the buffalo bull spermatozoa.     

^14CO2 Fixation and Translocation of Photoassimilates as Selection Criteria of Egyptian Taro Genotypes

The growth characterlstlcs, different physlological parameters, photosynthetic activity （^14CO2 fixation）, and the translocatlon rate of photoassimllates In different taro （Colocasia esculenta L. Schott） genotypes was studled In order to determlne the posslble use of these parameters as selectlon crlterla for dlfferent wldely used genotypes of taro （Delta No. 9, 15, 20, 21, and balady）. The results obtalned suggest that Delta No. 21 shows the most slgnlflcant increase In all parameters tested compared wlth the control （balady）, followed by Delta No. 9, 15, and 20, respectively. The results show a positive correlation between photosynthetlc actlvlty, translocatlon efflclency, and total yield. The selected clone Delta No. 21 Is recommended for cultlvatlon In the delta reglon of Egypt.     

Evaluation of tolerance in Chrysoperla carnea Steph. (Neuropt., Chrysopidae) to successive insecticidal treatments

The results obtained indicate that the Chrysoperia carnea collected from Giza region (where no insecticidal treatments were used), were more sensitive to malathion than those of Kafr El-Sheikh, where insecticides were used intensively. In predator colonies which were treated repeatedly with malathion, the sensitivity to malathion decreased from the first to the fifth generation. On the other hand, insects of the reference colony, showed a considerable increase in sensitivity within the same generations.     

Factors in the cryopreservation of bone marrow cells from children with acute lymphocytic leukemia.

Bone marrow cells from 42 children with acute lymphocytic leukemia in remission and 19 normal adults were preserved in liquid nitrogen for periods of up to 50 weeks. Many factors in the process of cryopreservation were investigated in an attempt to optimize the recovery of the bone marrow colony forming cells. The effect of cryopreservation on the cells which produce colony stimulating activity also was investigated. With optimization of this technique, it was observed that approximately 100% of the bone marrow nucleated cells were recovered and approximately 50% of the total colony forming cells were viable after 50 weeks in liquid nitrogen.     

Purification of β-xylosidase from Aspergillus tamarii using ground oats and a possible application on the fermented hydrolysate by Pichia stipitis

In this study we determined that Aspergillus tamarii Kita is able to utilize Avena sativa L. (oats) for the production of β-xylosidase under static or shaking conditions in submerged liquid-state (LSF), solid-state (SSF) and slurry-state (SlSF) cultures. The produced enzyme was purified and characterized. Maximum yield occurred under shaking conditions in SSF cultures (33.7 U/ml), with 24.9 and 5.5 U/ml produced in SISF and LSF cultures, respectively. Peptone was found to be the best nitrogen additive and enhanced enzyme production (41.5 U/ml). The produced enzyme was precipitated by ammonium sulfate (60 %) and further purified by gel filtration through a Sephadex G-100 and ion exchange column of diethylaminoethyl cellulose, with a yield of 40.57 % and 35.73-fold purification. Enzyme activity was optimal at pH 5.5 and 55 °C. The purified enzyme retained full activity even at the end of a 1-h incubation at this optimal condition. Midpoint of thermal inactivation (Tm) was recorded at 60 °C after 90 min of exposure. The Michaelis–Menten constant, maximal reaction velocity, turnover number and specificity constant of the purified enzyme were calculated to be 0.075 mg/ml, 71.42 U/mg of protein, 7.14/S and 95.2 mg/ml/s, respectively. The inability of the purified enzyme to hydrolyze celluloses indicated that the enzyme was a free cellulase. The most efficient enzyme activators were Mg2+, followed by Mn2+ and Zn2+ in that order. The molecular mass of the purified enzyme was 91 kDa as determined by SDS-PAGE. The possibility of using the fermentation of ground oat hydrolysate for the production of ethanol and xylitol in the presence of Pichia stipitis Pignal was assessed. The maximum production of ethanol and xylitol were obtained after 72 h of fermentation, resulting in 11.06 and 21.51 g/l respectively.     

The substrate specificity of two yeast strains utilizing hydrocarbons

StrainsCandida lipolytica 4-1 andCandida lipolytica K were compared in their growth and dawaxing capacities during batch growth on model gas oil. The model gas oil was composed of a mixture of even-numbered puren-alkanes (n-decane ton-dotriacontane) dissolved in dewaxed gas oil. The results show that both strains differ in their substrate specificity and in the sequence of utilization of individualn-alkanes. Strain K, previously used for dewaxing of mineral oil, has its substrate specificity shifted toward the highern-alkanes.     

Amylase of the thermophilic actinomycete Thermomonospora vulgaris.

alpha-Amylase of the thermophilic actinomycete Thermomonospora vulgaris was partially purified. Maximal enzyme activity was obtained at 60degreeC and pH 6.0. KM value was l.4%. The effect of some metal salts on enzyme activity was studied. Enzyme activity was inhibited by by KCN, EDTA, and iodoacetate. Inhibition by EDTA was completely nullified by CaCl2, but the inhibition by iodoacetate was not overcome by 2-mercaptoethanol. Exposure of the enzyme to pH 7.0 and 9.0 for 2 hr. did not affect the enzyme, but exposure to pH 3.0 for few minutes completely inactivated the enzyme. Exposure of the enzyme to 60degreeC resulted in an appreciable inactivation and exposure to 80degreeC completely inactivated the enzyme. Addition of CaCl2, 2-mercaptoethanol, or enzyme substrate the 60degreeC exposed enzyme. However, bovine serym albumin had a protective effect when the enzyme was exposed to 60degreeC but not to 80degreeC. The enzyme was stable in the presence of 8 M urea.