مجله زیست شناسی ایران
سال بیست و پنجم شماره 3 (پاییز 1391)

Aeluropus lagopoides is a Graminaceae related halophytic plant belongs to Poaceae family that grows in salty soils. In this research، several indicators were studied on plants under different concentrations of NaCl in hydroponic culture. Comparison the fresh and dry weights of roots، shoots، and whole plants under various treatments determined that the highest growth rates occur in the presence of 300 mM NaCl، however، lower and higher salinity reduces the growth rate. While the root length was highly depended on the salt concentration، shoots height did not vary significantly. Variances analysis showed that cations (Na+ and K+) are distributed differentially in the roots and shoots when the control and salt-treated plants were compared، and as a result، salinity had significant effect on roots and shoots Na+ content. In general، it may be stated that Aeluropus lagopoides reacts differently to various concentrations of Na+. Apparently، at low environmental NaCl concentrations the root system is developed and the absorbtion of cations is increased to provide water and essential minerals. In other words، it uses mineral osmolytes that are not toxic for the cell at low exogenous NaCl concentrations in order to maintain intracellular water and osmotic pressure، whereas at medium and high concentrations of NaCl، organic osmolytes like glycine betaine and proline are accumulated، respectively، to regulate osmotic pressure. As a result، the rate of plant growth is reduced in order to stand high salinity for a while. Furthermore، it seems that because of the strongly regulation of Na+ and K+ transport from root to shoot their contents are regulated tightly in shoots.

Six nitrogen-fixing bacteria which were isolated from root of cultivated rice and wheat and also one strain from a kind of biofertilizer، identified as Azospirillum with PCR amplification of 16S rDNA gene. Among the Azospirillum isolates from rice and wheat roots، one isolate from wheat (Golestan cultivar) and another from rice (Tarom cultivar) were selected for comparison of their cell wall degrading enzymes activities، because of more enzyme activity in cellulose، CMC (Carboxymethylcellulose)، salicin، pectin، NBRIP and phytin media. Azospirillum strain was isolated from rice had CMCase and phytase activities significantly more than one isolated from wheat، 31. 77% and 46. 99% respectively، but the FPase activity of both strains were nearly similar. The reason for Tarom colonization by the strain with higher activity of cellulase and phytase may be related to more celluletic cell wall and phytin content of this cultivar in comparison with Golestan.

In this study، a collection of 26 dairy products were subjected to bacteriocin analysis by using a culture-independent approach. The culture-independent approach involved extraction of total bacterial DNA directly from the products، this is followed by a polymerase chain reaction (PCR) using three pairs of specific primers (enterocin A، enterocin P and enterocin As48). The PCR analysis showed that only enterocin A was predominant in all study samples، however the other genes were absent. The absent of other bacteriocins in 26 samples، give the idea that Enterococcus spp are predominant bacteriocin producing LAB in different dairy products obtained from different area in Iran. Also the PCR approach was found to have a much higher sensitivity for detection of bacteriocin producing strains in dairy products in a fast، reliable، and reproducible manner.

Astrocytes are the aboundent cell type in the central nervous system. They play role in maintenance of normal brain physiology. In addition، astrocytes become reactive during injury of the central nervous system and have important roles during CNS inflammation. Shikonin، is a main compound of the roots of Lithospermum erythrohizon and Arnebia euchroma that has various biological activities، including anti- inflammatory، anti- HIV1، antimicrobial، anti- thrombotic and anti-tumor properties. The aim of the present study was to investigate the cytotoxic effects of different concentration (20µM-5µM) of shikonin on primary astrocytes and cell line 1321N1. We used MTT reaction to assay cell viability and stained the cells with DAPI to investigate the cell death. The results show that shikonin have dose dependent effects on this cells، in high concentration it is toxic for cells but in its low concentration shikonin has not the cytotoxic effect on cells.

Brevinin-2R، consisting of 25 amino acid residues، from the skin of the frog Rana ridibunda has potent antimicrobial and low hemolytic activity. From a structural point of view، this peptide has an N-terminal hydrophilic region، and a C-terminal loop region delineated by an intra-disulfide bridge، which is a common structural feature of antimicrobial peptides from Rana species. To investigate the structural features for antimicrobial، hemolytic activity and proteolytic stability، analogues diastereomer Sami-D brevinin-2R were synthesized and characterized. Structure-activity relationship studies revealed the importance of the amphipathic α-helical conformation of the reported peptides in inducing antimicrobial effects. Analogues D shows lower antimicrobial activity than brevinin-2R and did not show any hemolytic activity up 400 µg/ml whereas the brevinin-2R show low hemolytic activity. Circular dichroism spectra and the retention time on the C18 reverse phase column revealed that the brevinin-2R formed an amphipathic loop which increased hydrophobicity and helped to induce the α-helical structure in the membrane-mimetic environment. The hemolytic activity of brevinin-2R and its analogs also correlated well with the retention time and the α-helicity.

Stress effects on epilepsy excite different dissections. To clarify more، we studied the influences of acute and repeated stress on convulsions epilepsy elicited by pentylenetetrazole (PTZ). Adult male Wistar rats (200-250g، 10≥n≤7) were used. Two PTZ control groups، first with one session of injection (45 mg/Kg PTZ i. p.) and second with 3 session of injection (25 mg/Kg PTZ، with 15 minute interval) and two sham groups with vehicle (saline) injection instead of PTZ were used in this study. Three experimental categories، each one contain the above groups of PTZ were designed، animals in the first categories expose to forced swim stress 30 min before PTZ treatments. Treating of PTZ was done for the second categories 24 h after swimming and for third one 24 h after 3rd sessions of swimming (24h interval between each session)، after PTZ treatments the epilepsy behaviors were recorded. Forced swimming 30 min before one session of PTZ، reduced seizure (P<0. 05) 5 min after PTZ injection، Swim stress 24 min before one session of PTZ، reduced seizure (P<0. 01) during 10-15 min after PTZ injection. In one session of PTZ treating، 24h after repeated swim stress، reduced seizure during 5 (P<0. 01) and 10-15 min (P<0. 01) after PTZ injection was observed. Forced swimming 30 min before three session of PTZ، increased seizure 5-10 (P<0. 01) and 25-30 min (P<0. 05) after PTZ injection، Swim stress 24 min before three session of PTZ، reduced seizure (P<0. 05) during 15- 25 min after PTZ injection. In three session of PTZ treating، 24h after repeated swim stress، reduced seizure during 15-25 (P<0. 05) after PTZ injection was observed. Stress elicited both exciting and inhibitory effects on PTZ induced seizure. If it supposes that PTZ (45 mg/kg) saturates excitatory effects، so the inhibitory effects remains for stress، but PTZ (25 mg/Kg) has little influence on nervous system for revealing epilepsy، thus exciting part of stress can add to functions of PTZ and strength its effects. It may that repeated stress ability for recruitment of compensatory systems which regulates increased neurons excitation، at least in part، is responsible for inhibitory effect of repeated stress on PTZ induced seizure.

Ciliophora are the most diverse group of Protozoa that live in Brackish، Saline as well as fresh water. In Iran few works have been done on free living Ciliophora. In the present study we consider the density of free living Ciliophora for a period of one year from April 2006 to March 2007 in Ghareh Kahriz River. In the present study، the fluctuation of physico – chemical parameters (air and water temperature، dissolved oxygen، carbon dioxide، pH، total hardness، and total solids)، in relation to the population density of free living ciliates from three sampling sites in the length of Ghareh Kahriz river were considered. Maximum population density of free living Ciliophora observed in summer and autumn and in the sampling sites of 2 and 3، respectively. Paramecium caudatum and Litonotus fasciola showed، respectively، the maximum and minimum population density during the period of study. The high population density of free living ciliophora is due to the moderate water temperature، pH، dissolved oxygen as well as more food concentration due to the entrance of city west water drainage in summer and autumn and sampling stations 2 and 3. High water current، cold weather، and low food concentration in winter and spring might be responsible for the population density fluctuations in the present study.

Inflammatory bowel diseases (IBD) are the one of the most comment alimentary diseases. Etiology and pathogenesis of IBD remain obscure. There is substantial evidence that proinflammatory cytokines such as Interleukin-6 (IL-6) and Tumour Necrosis Factor-alpha (TNF-alpha) exhibit a key role in the inflammatory process. In the last decade investigations were done on treatment and pretreatment effects of some modulators and inhibitors of these mediators which emphasize different aspects of experimental colitis models mimicking IBD in human. The aim of this study is investigation of therapeutic and prophylactic effects of pomegranate، fig and date in daily regimen in experimental acute colitis model on rat. The results of this study show that pomegranate juice induces both therapeutic and prophylactic effects and date has only therapeutic effect on colitis.

In this trial، 90 Common carp (Cyprinus carpio) was sampled from a bay during April - Jun 2008، and some reproductive characters were studied. The correlation between gonadic characteristics (absolute and relative fecundity، gonad weight، Gonadosomatic index، diameter of egg and number of egg per gram) with fish size (Length and weight) and hepatic index were determined with Pearson and fecundity was calculated by gravimetry method. Also، the broodstocked were divided into 6 groups on their total length، and compared with Duncan test (α=%5). In broodstocks with length of 29. 5 cm and 44. 5 cm hepatic index were 0. 43± 0. 2 and 0. 32±0/11 and gonadosomatic index were 12. 12±1. 98 and 9. 89±1. 18 respectively. The correlation between treatment were not significant (P>0. 05). According to the results، maximum and minimum absolute fecundity were 156238. 8±64003. 47 and 52429. 5±7630. 39 respectively and relative fecundity were 94335. 5±12698. 06 and 130581. 5±12508. 19 per kilogram body weight. The results show that increasing fish size، the absolute fecundity was increased significantly (P<0. 05)، but the relative fecundity not influenced by fish size. The highest correlation coefficient was observed in absolute fecundity with gonadal weight (GW) and relative fecundity with gonadosomatic index (GSI). With increasing fish size، the number of egg per gram were decreased but the correlation between them were not significant (P<0. 05). There are significant relationship between total weight and total length to egg diameter (P<0. 01). The index of total length of fish can be applied as the more subtle factor to select of the broods of cyprinus carpio.

Daisy is one of the most consuming cuttings flowers in the world. One of the problem in trading of twins flower is short postharvest life or postharvest case for increasing quality. Producers have solved this problem by using chemical preservatives. The goal of this research was comparing between vase-life of flowers treated with nanosilver with AgNO3 and used sucrose as a energy source. The items that were measured were vase-life of flowers، changing in weight percent of opened flowers during the shelf-life were evaluated and compared.

Saffron (Crocus sativus L.) is a perennial herbaceous rosette، which has permanent underground stem bases called bulb or corm and purple petal and red three branches stigmas. The stigmas contain three major compound، crocins (carotenoids compound responsible for color)، picrocrocin (responsible for taste) and safranal (responsible for odor). Crocin that is carotenoids compound of saffron as an anticancer prevents cancer cell development. In this research saffron collected from Ghaen and Tabas regions was quantified by HPLC and qualified.

Lagerstroemia indica is a wide spread garden and ornamental plant appreciated for its long lasting summer flowering and flower color (from white to purple). This genus is belonging to Lythraceae family some which especially Lythrum are notable because of heteromorphic stamens and styles. Light and electron microscopic studies were taken on the flower structure and stamen and pollen dimorphism. Perianth is hexamerous; the 6 sepals are synsepalous and leather like and the petals are unguiculate، with an oval to orbicular crispate limb. The stamens are dimorphic، 6 outer stamens are usually larger، both as to filament and anther، and reddish in floral buds and opened flowers. Instead، inner stamens (29-30) are smaller and bright yellow in color. In the end of first day of flower opening، outer and inner anthers were observed as reddish and yellowish respectively. Both anthers had extended epidermal cells diferentiated into the upper and lower epidermis significantly. Anthers were dorsifix، extrose، dehiscing by longitudinal slits. Cryomicroscopic studies showed extended epidermis and functional pollen grains (contain many organelles) in outer anthers. The pollen grains from outer anthers were smaller، thin walled and more regular in compared to those of inner anthers. Large anthers produced tricolporate pollen grains while in inner anthers، pollen grains showed some features such as pseudocolpi، pseddopores and exin protrusions. Pollen surface in outer anthers was relatively blunt in the polar region and meridional ridges of mesocolpial regions and in the other regions was scabrate while pollen surface in inner anthers was between striped and regulate in the polar regions and meridional ridges of mesocolpial regions and in the other regions was as distinct regulate to verucate and punctuate. The gynoecium was five-carpellate، and the placentation was axial.

In this research، essential oil content and composition of Artemisia sieberi was investigated. In addition، the antimicrobial effects of the essential oil، methanol extract and it’s different fractions were studied. The aerial parts of A. sieberi were collected from Firuzkuh. The plant materials were dried in shade and powdered for extraction. The essential oil was obtained by hydro-distillation and analyzed by GC and GC/MS. The results showed presence of 20 components. The main constituents of the A. sieberi oil were 1،8-cineole (47. 6%)، camphor (35. 5%) and camphene (8. 3%). The methanol extract was prepared by maceration، then the butanol، chloroform and water fractions were prepared from methanol extract. Finally the antimicrobial effects of the essential oil، methanol extract and the fractions were studied against Escherchia coli، Pseudomonas aeruginosa، Kelebsiell penomonia، Bacillus subtilis، Bacillus cereus، Micrococcus luteus، Staphylococcus aureus and Yersinia enterocolitica. The antimicrobial effect of the essential oil of Artemisia sieberi against Gram positive bacteria showed the oil produced inhibition zone more than 20 mm on all Gram positive bacteria. So the essential oil showed strong effects against these bacteria equal to tetracycline and erythromycin. Study antimicrobial effect of the essential oil of Artemisia sieberi against Gram negative bacteria showed no effect on P. aeruginosa، but strong effect against K. pneumonia. Comparing the effect of essential oil on E. coli with synthetic antibiotics، gentamicin and carbenycilin showed that essential oil was stronger. The effect of A. sieberi oil on Y. entrocolitica was less than gentamicin and carbenycilin. The results of antimicrobial study of the extracts and fractions showed different effects. For each bacterium some fractions with special polarity showed larger inhibition zones. Methanol extract produced the biggest inhibition zone on Y. entrocolitica، while it has no effect on E. coli. So these extracts or their special fractions can be used in drug formulation for treatment of some diseases.

Plants maybe affected directly or indirectly by allelochemicals which released from plants or microorganisms. In this study، the allelopathic effect of leaf leachate of Eucalyptus camaldulensis Labill was examine on germination، growth rate، morphological and physiological criteria of sorghum (Sorghum bicolor) and kidney-bean (Phaseolus vulgaris). Leaf leachate was tried at 5، 10 and 20 % concentrations and sterilized distilled water used as control. Seed germination، seedlings dry matter، shoot/root length were significantly reduced by all concentrations in both species (at 0/05 level). Decrease in chlorophyll content، soluble sugar content and consequently protein content is proportional to the increase in concentration of leaf leachate in both species. The results showed that the inhibitory effect of leaf leachate on germination، growth rate، morphological and physiological parameters in dicot (P. vulgaris) plant was more than monocot (S. bicolor) plant.

In this study، the antioxidant and antiradical activity of the methanolic extracts of leaves، stem and seeds of Asperugo procumbens L (Boraginaceae). were investigated. Total phenolic content، reducing power، scavenging capacity for (DPPH، nitrit، hydrogen peroxide and superoxide) radicals، iron chelating activity and the rate of radical decay were evaluated in extracts. Extract of seeds، with the highest phenolic content، showed the highest reducing power and free radical scavenging capacities. Chain-breaking activity measurement allows the rate of the radical decay to be determined. No correlation was found between phenol content of the extracts and their chelating activity. Regarding to the results، it seems that the seeds of A. procumbens L. are good source of natural antioxidants and could be used to prevent free-radical-induced deleterious effects.