IRANIAN JOURNAL OF BIOLOGY
Year:2005 | Volume:18 | Issue:2|Papers Count:10

One of the most diver effects of salinity on crop growth is the accumulation of toxic ions, particularly sodium, in plant tissue. Seed treatment with calcium nitrate may improve seed germination under salt stress by reducing uptake of sodium and chloride ions. This research was conducted to study the effect of seed treatment with calcium nitrate on distribution of Sodium and potassium in seedlings of two rice varieties under saline conditions. Therefore, a factorial experiment was performed based on Completely Randomized Design with 40 treatments and 3 replication. The treatments were consisted of different concentrations of calcium nitrate (0, 1, 5, or 10 mM), EGTA (calcium chelator, with 5 mM concentration), four levels of salinity (0, 50, 100, 150 mM of NaCl), and two varieties of rice (Tarum and Gerdeh). The results indicated in both varieties, increasing the salt concentration caused a reduction in K+ concentration of root and shoot, but the Na+ concentration and Na+/ K+ ratio increased in shoot and root. The EGTA treatment induced a reduction in K+ concentration of root and shoot of both varieties, but Na+ content and Na+/ K+ ratio in these organs was increased by this treatment. In contrast, 10 mM of calcium nitrate under all salt concentration caused a reduction in sodium content and Na+/ K+ ratio of root and shoot, but potassium concentration in these organs was increased. In conclusion, Ca(No3)2 was effective to reduce the adverse effects of salinity in both varieties.

Chromium is an essential micronutrient in human and animals. Trivalent form of chromium as an important component of a balanced diet is necessary for proper carbohydrate and lipid metabolism. One of the suitable ways for preventing of chromium deficiency and its undesirable effects is using of chromium accumulator plants in daily diets. For this purpose, Cr+3 and Cr+6 accumulation effects on growth and chlorophyll content in parsley plants were studied. Seedlings of parsley (Petroselinum crispum) were grown in hydroponic culture (Hoagland) containing various concentrations of Cr+3 (0.1, 0.25, 0.75,1, 1.5, 2 and 3 mg/l) and Cr+6 (0.1, 0.25, 0.5 and 0.75 mg/l) for 5 weeks. After harvesting, the influence of these ions on root and shoot dry weights, root and shoot lengths and chlorophyll (a, b and total chlorophyll) content was studied. Besides, chromium accumulation was determined in roots and shoots. Data analysis was carried out and means were compared at 0.05 level. Results showed that with increasing Cr+3 and Cr+6 concentrations in medium, the root and shoot dry weights and lengths and chlorophyll content decreased. Significant decrease in the root and shoot dry weights were observed at 3 mg/l and 2-3 mg/1Cr+3, respectively. In plants treated by Cr+6 , significant decrease in the root and shoot dry weights was observed at 0.75 mg/l. Cr+3 caused significant diminishment in the root and shoot lengths from 0.75 mg/l up to 3 mg/l. While significant decrease in the root and shoot lengths of plants treated by Cr+6 was observed at 0.75 mg/l and 0.5-0.75 mg/l, respectively. Decrease of chlorophyll a, b and total chlorophyll were significant at the highest Cr+3 concentrations (3 mg/l). The levels of chlorophyll a, b and raw chlorophyll decreased significantly at 0.25 mg/l and higher concentrations of Cr+6. With enhancing Cr+3 and Cr+6 concentrations in medium, the levels of these ions in the roots and shoots increased significantly. Chromium accumulation in the roots was much higher than the shoots.

Flooding stress has important morphological and physiological effects on crop and wild plants. Flooding is induced by excessive irrigation or rainfall in soils with poor drainage. One of the important effects of flooding is the reduction of nutrient and water uptake in plants. Production of reactive oxygen species (ROS) and induction of oxidative stress in plant tissues are some of the other effects of flooding. Malondealdehyde (MDA) production is the indicator of lipid peroxidation reactions. A significant increase in MDA in plants which were flooded probably is the indication of fatty acid oxidation in the present of free radicals generated by flooding. In this research, seeds of Capsicum annum were sown in pots filled with vermiculate and then the pots were transferred to a controlled growth room with photoperiod of 16/8h light/dark and temperature 27/23 day/night. After three weeks, the seedlings were flooded for 3, 5 and 7 days. After sampling, antioxidant contents including ascorbic acid (ASA), carotenoids, as well as lipid peroxidation reactions and uptake of mineral elements were measured. In those plants which were flooded, ASA increased significantly. Flooding caused a significant decrease in chlorophyll b content (p=0.05) in those plants which were flooded for 5 and 7 days. Flooding also significantly decreased carotenoid in flooded plants when compared with controls. Flooded plants had a much higher MDA content than unflooded control plants. Potassium content of flooded plants decreased significantly, but sodium ion content was 2 to 3 times more in flooded plants in comparison with controls.

Dehydrogenation and biooxidation of organic compounds such as aliphatic and aromatic petrochemicals can potentially give rise to production of precious substances. Much more expensive chemical feed stocks are produced from low cost substrates using microbial dehydrogenases and biotechnological methods. A screening program resulted to isolation of 14 strains of Bacillus spp. with bioconversion capability from forest soils of north of Iran. Presence of alcohol dehydrogenase was indicated spectrophotometrically and assayed by determining the amount of NADH yielded through the reactions. Most of the isolates showed an enzymatic activity ranging between 0.2 to 0.7 U/mg-1 proteins.One of the isolates (Bacillus megaterium strain L2) showed the highest dehydrogenase activity (0.8U/mg-1protein). The strain showed the ability to consume a wide range of substrates as the sole carbon source including xylol benzyl alcohol, cyclohexane, and aliphatic alcohols such as methanol, ethanol, propanol, and buthanol. Crude extract of the bacterial cells showed dehydrogenase activity in the presence of all of these substrates. Higher dehydrogenase activities were obtained in the presence of linear alcohols, in comparison with aromatic ones. When benzyl alcohol was used as substrate, the reactions were not limited to a simple dehydrogenation bioconversion, and further enzymatic reactions occurred and several metabolites were produced at different concentrations. 4-hydroxy- 4-methyl-2-penthenon was produced as one of abundant end products with final relative concentration of 45.6 percent. Thus, it is expected that a range of enzymatic reactions or bioconversion processes such as biooxidation can be catalyzed by further extraction and purification of enzymes.

Cellulose is the most abundant biopolymer in nature which is made of glucose units with  b(1,4) links. It is hydrolysed to glucose through the cinergistic function of three groups of enzymes namely endogluconases, cellobiohydrolases and  betaglucosidases. The most important enzyme in this enzyme complex is b-1,4 endoglucanase (egl) which has industrial applications. In this study genomic DNA from T.reesei PTCC5142 (high EglI enzyme producer, 0.37 U/ml) and specific primers (EB1 and EF1) were used for eglI amplification. The amplified DNA fragment (1524 bp) was cloned into pBluscript SK(+) and sequenced. Also eglI cDNA was synthesized (1380 bp), cloned and sequenced. Comparison of genomic DNA and cDNA sequences showed that eglI gene contains two introns (70 bp and 57 bp) and codes for a polypeptide with a 459 amino acids long. Alignment of eglI sequence revealed three nucleotide differences with eglI gene from T. reesei VTT-D-80133 which altered two amino acids in its catalytic domain. The superposition, using SWISS-MODEL, of all backbone atoms (1480) between the template structure and eglI of T. reesei VTT-D-80133, rendered a Root Mean Squared Deviation (RMSD) of 0.47 A. While superposition over equivalent 370 C a atoms gives a RMSD=0.4 A.

Pseudomonas aeruginosa is one of the most important opportunistic human pathogens. This bacterium is ubiquitous and exhibits innate resistance to a wide range of antimicrobial agents. The purpose of this study was to compare antimicrobial susceptibility patterns and plasmid profiles in hospital P.aeruginosa.During 8 months, 104 isolates of P.aeruginosa from different clinical (urine, blood, stool, sputum…) and environmental samples (sink, disinfectant solution, bed, hand,…) were collected. Susceptibility pattern of these isolates was obtained by disc diffusion (Kirby-Bauer) method. The alkaline lysis method was used for detection of plasmids.8% of 104 isolates of P.aeruginosa was environmental. Antimicrobial resistance was as follows: linkomycin (100%), ceftazoxime (99%), lomefloxacin (94%), ceftazidime (60%), ticarcillin (50%), ceftriaxone (44%) cefoperazone (37%), tobramicyne and ciprofloxacin10mg (35%), piperacillin and gentamicin (34%), carbenicillin (25%), ciprofloxacin30mg (24%), amikacin (22%), imipeneme (1%). All isolates were MDR but plasmids were detected in 29.8% isolates with 15 different plasmid profiles. The latter constituted 61.7% of total isolates which showed resistance to 10 or more antibiotics. There were specific correlations between some plasmid and resistance to antibiotics. The frequency of plasmids in P.aeruginosa was low (29.8%), indicating that the resistance genes are likely to be chromosomal. In spite of limitation of plasmid profiling, it is easy to perform and thus can be a useful method in epidemiological study.

It has been recently reported that noscapine, an antitussive medicine, could antagonize bradykinin-induced responses. Concerning the role of bradykinin in inflammatory processes, the effect of noscapine on carrageenan-induced inflammation in rat hind paw was investigated. Healthy male Wistar rats were distributed into eight groups. Acute inflammation of hind paw was induced by subplantar injection of 0.1 ml of I% fresh suspension of carrageenan. Noscapine at doses 0.5, 1, 2, 5 and 10 mg/Kg/BW and indomethacin (l0 mg/Kg/BW), as a known anti-inflammatory drug, were administered intraperitoneally an hour before carrageenan injection. The thickness of the hind paw was measured with caliper before and I, 2, and 3 hours after carrageenan injection. The rat hind paw inflammation was decreased using noscapine. This effect was significant at second and third hours after carrageenan injection. The dose 5 mg/Kg/BW dosage three hours after carrageenan injection was the most effective one similar to anti-inflammatory effect of indomethacin at the same dosing time. This effect was diminished by using higher doses (10 mg/Kg/BW).

Identification and determination of predator insects abundance of Panonychus ulmi Koch along with biology of Stethorus gilvifrons have been investigatede in Padena region as well in Plant Pests and Diseases Res. Laboratory of Esfahan. Sampling of predators done at fort night interval from infested apple orchards by mites. Shaking methods of leaves and regular inspection of orchards were used for mite predators collection. Identified species of predator insects are as follow: Stethorus gilvifrons Mulsant , Stethorus punctillum Weise , Scymnus pallipes Mulsant , Scymnus flavicollis Redtenbacher , Orius niger Wolff , Aeolothrips intermedius Bagnall and Chrysoperla carnea Stephen. Among these, higher percentage belonged to S. gilvifrons (27, 8%). The biology of the species was studied under 25-28 oc , RH %55 ± 5 , and 14L: 10D. Its development from egg to adult lasted 14.72 days on average and its total fedding from Tetranychus urticae was 212. 34 mites on average. It layed daily 6 eggs on average.

In this investigation, 48 live specimens of the genus spermophilus Cuvier, 1825 colected from the type localities within various of Iran have been studied. The specimens were studied in detail with respect to their karyological characteristics. The karyotypic analysis of Spermophilus fulvus Lichtenstein, 1823 from Iran showed that its diploid chromosome number is 2n=36 the X chromosome is metacentric and medium in size and the Y chromosome is the smallest complement of the karyotype seems to be acrocentric and the autosomes contain eleven pairs of large to medium – sized submetacentric .Five pairs telocentric and othe one pair is metacentric. On the species spermophilus xanthoprymnus, Bennet 1385 diploid chromosome number is 2n=42, X chromosome is metacenteric and medium in size, and the Y chromosome is the smallest chromosome and it’s acrocentric, and the autosomes contain seven pairs of large to medium – sized submetacentric . Four pairs of large to medium – sized subtelocentric. Eight pairs of large to small acrocentric and one pair of small metacentric.