JOURNAL OF ANIMAL PHYSIOLOGY AND DEVELOPMENT (QUARTERLY JOURNAL OF BIOLOGICAL SCIENCES)
Year:2010 | Volume:3 | Issue:2 (9)|Papers Count:9

Drought stress is considered as a major limiting factor in plant growth and development. this study was conducted to determine the effect of various levels of drought on S. leriifolia. The study was carried out as a complete randomized design with 4 replications in pot and greenhouse condition. The drought Levels were included 0, -2, -4, -6, -8 Bar. Soil misture various potentials was measured using a pressure plate devise.After six weeks of drought treatment, variations in chlorophyll, soluble sugars, pottasium, fresh and dry weight of root and shoot, shoot lenght were measured. Result showed chlorophyll a, b contents, fresh and dry weight of root and shoot and shoot lenght significantly decreased but soluble sugars content in root and leaf, potassium concentration in shoot increased with increasing levels of drought stress. Increasing of soluble sugars and pottasium content possibly indicate the establisshment of a tolerance mechanism to drought stress in Salvia leriifolia Benth.

The effects of AlCl3 with different concentrations of 0, 50, 150, 300, 450, 600, and 750 mM on certain physiological parameters in bean plants (Phaseolus vulgaris L.) during 25 days growth period (15 days Treatment) in hydroponic cultivation environment were studied. With increasing aluminium chloride, carbohydrate and protein contents were increased. In high concentrations of AlCl3, peroxidase activity increased, however, in 50 and 150 mM AlCl3 in comparison with control, peroxidase activity decreased and also with increasing aluminium chloride, catalase activity increased in comparison with control, but in 600 and 750 mM AlCl3 catalase activity decreased.

Cellulose is the most abundant biopolymer on biosphere and one of the most important constituent in plant cell wall. Biodegradation of cellulose in soil has an important role in Carbon flow and changing fixed Carbon to CO2, and in producing stable biological products and bioenergy. In this research fungus were isolated from soil of Zanjan and Abhar, due to great potential of soil mycoflora in degradation of cellulose. Then isolates were grown in selective media containing Avicel as Carbon source and their cellulolytic activity were measured by DNS method. Among 67 samples, Aspergillus niger is the the most prevalent fungus between isolates and it has the highest activity among the isolates of Zanjan and Abhar.

Penicillin G acylase (PGA) of Escherichia coli is one of the most widely used enzymes at industrial scale. It is used to hydrolyse penicillin G to 6-aminopenicillanic acid, an essential intermediate in the production of semisynthetic penicillins. Due to high industrial importance of PGA, numerous efforts have been made towards screening for strains overproducing this enzyme. The objective of this study was to screen clinical samples for isolation and identification of E. coli strains producing PGA enzyme.The E. coli bacteria isolated from clinical samples were screened for PGA activity using the bioassay method. This method is based on the use of Serratia marcescens which is sensitive to 6-APA but comparatively resistant to benzylpenicillin. After primary screening, the PGA production in positive isolates was verified by biochemical assay.Finally, the effects of incubation time, temperature, PAA concentration and media PH on PGA synthesis were studied and the optimum conditions for process were determined. The PDAB colorimetric method was used for quantitative PGA activity assay.Among 121 E. coli isolates were studied, only 3 isolates showed the PGA activity but one of them had higher activity. For the selected strain, the optimal condition for enzyme production was obtained in 0.1% PAA, media PH of 7-8, incubation time of 48h and incubation temperature of 32oC.The result of this study showed that biological screening method is a rapid and efficient method for dentification of PGA producing bacteria.

Nanobiotechnology is a novel science in the fields of industry, medicine and biology. Nanoparticles especially gold nanoparticles are subjected to have several applications in diagnosis and therapy of cancer. Ever increasing pressure to develop environmentally benign nanoparticle synthesis has lead to an interest in biotransformations as a route to growth of nanoscale structures. In this study, we have investigated biosynthesis of gold nanoparticles using Rhodococcus. sp isolated from Ahar copper mine (in north-west of Iran). The results showed the intracellular/ extracellular synthesis of gold nanoparticles by reaction of 1 mM aqueous HAuCl4 incubated at pH 7 after 24 h with Rhodococcus. Sp. The UV–vis and XRD of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of gold nanoparticles with average size of 50 nm.

Water quality is usually determined through detection of a few microbiological parameters, typically fecal indicator such as total coliform (TC), fecal coliform (FC), E. coli, Clostridium perfringens, Streptococcus faecalis (FS). Fecal indicators are found in elevated concentrations in human and animal feces. Water quality samples were analyzed for five bacteria, TC, FC, E. coli, C. perfringens, S. faecalis. Goal of this study TC, FC, E. coli, S. faecalis measured by the MPN method at this study and C. perfringenswas was detected by useing of litmuse milk and stormy fermentation. Results show that the number of TC less than 1000 MPN/100ml in 60% of samples and FC lees than 1000 MPN/100ml in 77% of samples and S. faecalis in 77% of samples was 3 MPN/100ml. Ratio FC/FS in 49% was more than 4 and also there was C. perfringens in 54% of samples. Present of fecal indicator bacteria in water indicates potential adverse health effects for indivduals or populations exposed to this waters. we conclude that there is a risk of infection for users of Zanjan, s fresh and surface waters.

The effects of different cytokinins (benzyl amino purine (BAP), Kinetine (Kin) in combination with different auxins (Indole butyric acid (IBA), 2, -dichlorophenoxy acetic acid (2, 4-D) were investigated on callogenesis and organogenesis of Chrysanthemum morifolium Ramat L. Leaves explants were cultured in the MS medium supplemented with different auxins and cytokinins. Results of using IBA and BAP in the media indicated that calli which were taken from medium with IBA (2 mgL-1) and BAP (0.5 mgL-1) produced roots and callus of IBA (1 mgL-1) and BAP (1mgL-1) produced shoots. By using 2, 4-D and Kin in the medium, rhizogenesis were occurred in the media supplemented with 2, 4-D (0.5, 4 mgL-1) and Kin (2 mgL-1).Subculture of calli increased rooting. Calli of medium with 2, 4-D (0.5 mgL-1) and Kin (2mgL-1) produced shoot after the first subculture in the free hormone medium. In the 2, 4-D and BAP treatments, maximum level of callogenesis and rhizogenesis were achieved. Calli in the medium supplemented with 2, 4-D (0.5 mgL-1) and BAP (1mgL-1) produced roots and shoots.

For studing of the effects of plant growth regulators on in vitro culture of Zinnia elegans, an experiment has been done by using different concentrations of Cytokinins (benzyl amino purin and kinetin) (1, 2, 3 mM) in Murashig-skoog (MS) culture medium by factoryel manner. The applied explants were embryos with halfed dicotiledons, in which, the percentage of their germinating (seeding), number and length of their leaves, length of shoots and roots were considered. The majority number of leaves were seen in BAP hormone in concentration of 3 mM.The best concentration for increasing the length of leaves was observed in BAP hormone in concentration of 2 mM. The branch formation was also seen in BAP hormone in 2 mM concentration. The most increase of stem length was related to BAP hormone in 1 mM concentration and the most increase of root length was related to Khn hormone in concentration of 1 mM.