Isolation, Identification and Distribution of the Gram-Positive Bacterial Isolates Contaminating the Drinking Water of Al Gedarif City, Sudan

In this study, the possible aerobic Gram-positive bacteria were isolated from the main sources of the drinking water in Al Gedarif city (raw and treated waters of Atbara River, main reservoirs and zeer waters of all sources). The isolates were identified using the manual identification tests (primary and biochemical). The primary tests identified the isolates up to the genera level. The results indicated that the isolates belonged to four genera (Staphylococcus, Micrococcus, Bacillus and Corynebacterium). However, the biochemical tests identified the isolates up to the species level. The species identified included three of the genus Staphylococcus, four of the genus Micrococcus and eight of the genus Bacillus, as well as the bacterium Corynebacterium diphtheriae. The study also included the distribution of the identified species in the different sources. It was found that Staphylococcus aureus and S. epidermidis were found in almost all sources. However, the other bacterial species were detected in some of the sources and absent in the others. On the other hand, S. saprophyticus, M. varians, M. kristinae, B. thuringiensis, B. pantothenticus and B. firmus were not detected in any of the underground sources

Investigation of the nanocrytalline SnO2 Synthesized by Homogeneous Precipitation

Nanocrystalline tin dioxide synthesized by the homogeneous pre cipitation method using the reaction of tin tetrachloride pentahydrate and urea solutions has been investigated. The nanocrystalline powder has been traced at different calcination temperatures (300ºC-1050ºC), and then characterized by using   Thermogravemetric analysis, differential thermal analysis and x-ray diffraction. The microstructure of the obtained nanoparticles has been examined by scanning and transmission electron microscopy. The average crystallite size, determined by x-ray diffraction, was found to be in the range of 3 –30 nm. The analysis exhibited a tetragonal phase.  Optical properties were investigated by a UV–vis absorption spectrophotometer. The calculated optical band gap lies between 4.47–3.71 eV as a result of increasing the calcination temperatures and crystallite size. Surface area and porosity of SnO2 nanoparticles are measured. Specific surface area which is related to pore volume and decreases from 155 m2/g at 100ºC to 3.3 m2/g at 1050ºC.Â

Production and characterization of Pectic enzymes from three fungi

Pectins are compounds  that  are resistant   to  enzymatic  cleavage  in most  organisms  and  plants, Studies  were  therefore  made towards finding methods for hydrolyzing these compounds. One such approach  is enzymatic hydrolysis.  Three fungi   (Trichoderma   viride,    Asperigillus     niger   and penicillum   digitatum)  are   used   for  production   of   pectinase  enzymes, Two  methods (reducing  sugar and viscometary)  were  used  for  measuring enzymes activities. Pectin and sodium polypectate compounds were used  as substrates. The  production of  pectinases by the three fungi was investigated in culture media. T. viride and P. digitatum  gave  maximum   production  of pectinase  enzymes  after  two  week  and  A. niger  gave  it  after  one week. Purification   by   ammonium    sulphate   precipitation,     showed   that   the maximum  pectinase  activity  was  at   80%   concentration for both fungi A niger and P. digitatum. By using  gel  electrophoresis, five bands were found to   give   pectinase  enzymes   activities. The   present   study   showed    the importance   of   fungi   as   sources  of  enzymes and recommends that more studies  must   be   done   in   the  field of  biotechnology to produce glucose  from natural products by  using fungi. &nbsp

Factors Affecting Activity of Cellulose Enzymes Produced By Three Fungi

Three fungi (Trichoderma viride, Asperigillus niger and Penicillium digitatum) were used in the present study for the production of the cellulase enzymes (carboxymethylcellulase and cellobiase). The effects of different metal ions on the activities of these enzymes were , caused a ++and Mn+ , K++, Ba++using the reducing group method. The addition of Ca investigatedsignificantly higher increase in the activity of the carboxymethylcellulase enzyme of the three . However, the addition ++and Zn++ e a less increase was found by the addition of Mgfungi, whilactivity. The activity of the is enzyme caused a decrease in th ++, and Fe++, Cu++, Cd+, Ag+of Naand +ence of Hg, but it was decreased in the pres+and K ++cellobiase was increased with Caat the was occurred A. nigerenzyme produced by cellobiasehe higher activity of the T.++Cd, however, ++Ca and ++900 ppm for Mn –500 , while it occurred at+900 ppm of K –200 of range P. and T. viride ase of bothobiFor the cell 900 ppm. –800 of at the range it occurred ,++Ba for . ++, no significant different was noticed with different concentrations of Cadigitatumfungi at all th ase enzyme of boobigave a lower activity for the cell ++On the other hand, Ba concentrations. The optimum temperature for the carboxymethylcellulase enzyme activity was at . P. digitatum and T. viride bothfor C 050 –C 0it was between 40 , whileA. niger50°C for C.0However, the optimum temperature for the cellobiase activity of the three fungi was at 40 The optimum activity of the carboxymethylcellulase enzyme produced by A. niger was at pH 4, and for that of T. viride was at pH 6. Two peaks were detected for the same enzyme produced by P. digitatum, at pH 6 and pH 7. However, the optimum pH value for the cellobiase enzymes produced by the three fungi was at pH 4.0only

The role of losartan and enalapril in the protection against stress-induced gastric mucosal ulceration in rats

Background: Angiotensin II (ANG II) is a stress hormone and its level dramatically increases in the stomach during stress. In addition, it generates reactive oxygen species (ROS) with cellular damage and inflammation. So the aim of this study is to evaluate the mechanism of losartan and enalapril in the prevention of stress-induced gastric ulcer through their action on mucosal prostaglandin (PGs) and antioxidant enzymes and compare between them.Methods: Thirty- six adult male wistar albino rats weighing 180-200 g were divided into 6 groups; n= 6. Groups 1, 2, and 3 were received saline (normal control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks. Groups 4, 5, and 6 were pretreated with saline (ulcer control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks duration. On 29th day, group 4, 5 and 6 were submitted to gastric ulcer by water immersion method, then animals of all groups were sacrificed, stomachs were excised for gross and microscopic examination and determination of the mucosal levels of prostaglandin E2 (PGE2), superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT).Results: Stress produced gastric ulcer and a significant decrease in all measured gastric parameters compared to normal control group. Pre-treatment of rats with losartan or enalapril decreased the stress-induced alterations in mucosal parameters, but only losartan caused a significant increase in CAT activity in addition.Conclusions: Antagonize the action of ANG II by losartan and enalapril have preventive advantages in stress-induced gastric ulcer and losartan has better influence as it has an additional effect on CAT activity

Effects of Some Essential Oils on Aspergillus flavus Growth and Aflatoxin Production

The present study aimed at investigating the effects of some essential oils on inhibiting fungal growth of A. flavus and aflatoxin production. Clove oil was found as the best among the six different oils tested against the radial growth at the concentration of 0.05. mL/100ml. However the other oils were also significantly better than the control except the Pumpkin oil. Different concentrations (0.00, 0.01, 0.03 and 0.05 ml/100ml) of only three of the oils were tested against the radial growth of A. flavus. Clove and Cumin oils were significantly effective than the control at all these concentrations. Although Pumpkin oil was slightly more effective than the control at its higher concentration (0.05) ml/100ml), it was not effective at its lower concentrations (0.01 and 0.03 ml/100ml). Clove oil was also the best in suppressing mycelial growth at the concentration of 0.05 ml/100ml. However, the other oils were also significantly better than the control, while, Pumpkin oil was non-effective. Spore germination was also affected by the oils tested. Clove oil gave complete inhibition at its higher concentration followed by Cumin, Rehan, Garlic and Desert date, while Pumpkin oil was the least one. Aflatoxin production was highly affected by the essential oils tested. Clove and Cumin exhibited a complete inhibition, followed by Rehan; Garlic and Desert date while Pumpkin oil was non-effective