IRANIAN JOURNAL OF BIOLOGY
Year:2009 | Volume:22 | Issue:3|Papers Count:21

Facilitation and competition were studied between perennial semi-shrub Artemisia aucheri Boiss and annual grass Bromus tectorum L. Near surface temperature and luminance, relative humidity of different soil depths and density of Bromus, were different under canopy of Artemisia as compared with those of the nearby open spaces. Soil humidity was the primary source for plant-plant interaction. Relative soil humidity weight was higher under Artemisia canopy, which was due to the lower air temperature and irradiance. Such conditions, enhanced establishment of Bromus under the canopy of Artemisia (facilitation effect). On the other hand, regression analysis indicated decreases in the Artemisia vigor by increasing the number of Bromus in its understory (competition effect). Accordingly, a cyclic dynamic is suggested, which starts by Artemisia establishment, continues with facilitation and competition, and terminates after Artemisa death. In conclusion, a high mortality rate of Artemisia shrubs in the Nasrabad rangelands, during dry years of 1999-2001, is partly because of the intense competition effects by Bromus tectorum.

Growth and physiology of plants influence by allelochemicals realeased from weeds by various methods. In this investigation, the effects of Hordeum spontaneum 10% w/v aqueous extracts on carbohydrates and proteins content and some oxidative enzymes activity of two wheat cultivars (Tajan and Shirodi) were studied. In the presence of allelopathic derived from Hordeum spontaneum, total proteins reduced in Tajan but increased in Shirodi cv. Polysaccharid content increased in Shirodi leaves by Hordeum spontaneum allelochemicala while the highest amount of reduced sugar observed in Tajan roots. We observed a decrease in ascorbate peroxidase, peroxidase and catalase activities, however polyphenoloxidase activity were increased. Protease activity decreased in the leaves while it increased in roots. The electrophoretic patterns of enzymes were differ with compared to control. Thus allellochemicals effect on different enzymes by various methods.

Water deficit stress is a common abiotic stress that seriously affects crop production in more parts of the world. Thus, in order to study the effects of water deficit stress and foliar application of ascorbic acid on the activity of some antioxidant enzymes, proline accumulation, lipid peroxidation, protein, chlorophyll, ascorbate and dehydroascorbate contents of grain corn (single cross 704), an experiment was conducted in Faculty of Agronomy of Tarbiat Modares University. Experiment was as a split-split plot in randomized complete block design arrangement with three replications. Water deficit stress was allocated to main plots (before flowering, after flowering and without stress). Ascorbic acid was used at two times (before and after flowering) in sub plot units and four concentrations (0, 50, 100, 150-ppm) in sub-sub plot units. Results showed that water deficit stress increased antioxidant enzymes activity, as this enhancement was remarkably in after flowering stress plots whereas, foliar application of ascorbic acid decreased it. In addition, water deficit stress decreased protein content and chlorophyll concentration in leaves. Proline and malondialdehyde content were increased in response to stress. Ascorbic acid prevented of degradation of protein and chlorophyll of leaves and decreased proline and malondialdehyde in leaves by reduction of water deficit stress. It was observed that cellular ascorbate concentration was increased by exogenous ascorbate application and dehydroascorbate concentration was decreased in water deficit stress treatments particularly in plots which were treated after flowering stress. In addition, plants were preferred ascorbate utilize as a scavenger than the enhancement enzyme activity in against stress. The latter could indirectly decrease enzyme activity and improved growth conditions for plants.

In other to investigate the effects of water deficit on yield and photochemical efficiency of photo system II of barley varieties, an experiment split plot based on randomized complete block design with three replications was conducted in Farm Seed and Plant Improvement Institute Karaj in 2002. In this study the main plots were irrigation in five levels (0, 20, 50, 75 and 100 % of plant water requirement) and sub–plots were barely varieties (Torkaman, Karon×kavir, Rihany, C-74-9, Ghorghan-4, Kavir×Badia). The result showed that water deficit caused an decreased in temperature of canopy, however varieties with warmer canopy under control treatment were tolerant to drought and showed higher yield than other varieties under drought condition. In water deficit treatment, photochemical efficiency of photo system II (ratio of Fv/Fm) declined significantly due to increasing of Fo and ultimately decreasing of Fv. Water deficit affected significantly on yield and yield components and it caused an decrease in all of their, although there was significant different among varieties under water deficit.

Awareness of gene action of traits is very important in plant breeding methods. Generation mean analysis (GMA) using parents. (P1 & P2) and their progenies (F1, F2, BC1 & BC2) in two mating groups was used to study the type of gene action and the best genetically model of traits under drought stress condition. The experiment was conducted using a randomized complete block design with three replications for each mating group. Generation mean analysis was performed using Mather and Jinks model and joint scaling test. The nine traits included spike length, spike number, pedancle length, awn length, grain yield, plant height, spike weight, grains per spikes and 100 grain weight were evaluated. The analysis showed disagreement of additive-dominance model for all traits, resulted that there is epistatic non-allele interactions between the genes of each trait. The distribution of traits was continuous in F2 and backcrossed populations, as a reason for polygenic inheritance of the traits. For the majority of the traits, additive gene effect was significant, but its magnitude was less than dominant gene effect. The amount of h/d for many traits such as grain yield was high (h/d>1), indicated the predominance of dominant gene effects in F1 progeny.

In the present study, 15 fungal samples were isolated from sugarcane bagasse which were able to grow on bagasse as the main carbon source. Morphological and microbiological studies showed that these three isolates were related to Aspergillus genus. Our experiments showed that the ability of As. niger, As. terreus and, As. fumigatus for bagasse degradation were 12.54, 9.85, 3.48 percent (in ratio to bagasse dry wight) and their lignin peroxidase activities were 10.02, 9.89 and 5.56 U/L in the presence of veratryl alcohol as an lignin peroxidase inducer after 21 days incubation, respectively. Cellulase activities of 47, 58 and 39 U/L were obtained by mentioned fungi, respectively. In this study the maximum lignin degradation activity was obtained for As. niger (12.54 percent) and maximum cellulase activity was measured for As. terreus (58 U/L). It seems that these isolates are efficiently able to use bagasse as the main carbon source for production of lignolytic enzymes.

Filamentous fungi such as Trichoderma spp. Produce a variety of chitinases that degrade chitin and play an important role in biological control of fungal diseases. In this research Trichoderma atroviride an over producer of chitinase enzyme among 30 Trichoderma spp. isolates used for study of antagonistic effects on phytopathogenic fungus, Rhizoctonia solani (causal agent of root rot disease in sugar beet). Results of dual culture, slide culture, in vitro and in vivo studies demonstrated the ability of T. atroviride inhibitory effect on R. solani mycelial growth.

Assessment of genetic diversity is highly essential in order to identify different genes, distance estimation between and within populations (enter specific and intra specific relationships), and determination of heterosysis value. In spite of very reach pistachio genetic resources in Iran, a few studies have been carried out on this genus. In the present study, genetic diversity of 32 pistachio cultivated genotypes of Kerman province were investigated using RAPD molecular markers. 136 polymorphic bands were found from 10 primers. Zero–one matrix dendrogram of immigrated bands were drawn by NTSYS software with Dice coefficient. Based on the results, the investigated genotypes were clustered in six groups. The similar genotypes which collected from different regions, were placed in the same groups. Also the results indicated that Kerman Ohadi and Zarand Ohadi genotypes were completely similar. Furthermore, comparison between two and three dimensional plots of principle coordinate analysis method and the clustering method showed that the results were similar. This fact can be considered for investigating diversity and primer selection .

The study was performed in 2007, at four hospitals in Sistan and Balochestan. The main objective was to determine the sterility of anesthetical instruments and also to identify the most common contaminating microorganisms. Samples were taken from the instruments and were cultured under sterile conditions. Among the 147 samples taken, 49 yielded positive cultures which froms a high overall percentage. Hospital 1 had the most positive cases while number tree hospital had the least. The most common pathogenic microorganisms in order were: Gram-positive Bacill, Corynebacterium, Geram-negative Bacill, Neisseria, Staphylococcus, Gram positive Diplococcus. We have concluded that lack of attention in sterilizing and also maintaining the sterile status of anesthetical instruments are among the infecting factors.

Green fluorescent protein can be joined to recombinant antibodies to produce recombinant fluorescent antibodies. Recombinant fluorescent antibodies are functional in different assays in which fluorescent antibodies are traditionally used. Their intrinsic fluorescent renders them directly applicable in many fluorescent-based assays currently used in a wide range of life science. The aim of this study was to manipulate a phagmid antibody vector to produce recombinant fluorescent antibodies by cloning the EGFP gene. With this aim the sequence of a linker peptide and two restriction enzyme sites were added to the EGFP gene and the NcoI restriction site in this gene was removed by means of site-specific mutagenesis. The modified gene was then cloned into pIT2 vector which was subsequently transformed into Escherichia coli. After confirming the sequencing results, this new vector was called pGK-29. Finally, the activities of the recombinant vector were tested by fluorescent microscopy and ELISA experiments. The results revealed that the produced chimeric protein has fluorescent activity and is able to recognize its corresponding antigen.

The moderately halophilic bacteria tolerate extensive range of sodium choloride salt. Intracellular concentration of salt is lower than medium, thus membrane bound proteins and extracellular proteins have halophilic/halotolerant qualities. To isolate the moderately halophilic bacteria, sampling was carried out from Persian Gulf water and different parts of tannery factory. Samples were enriched in selective media for halophils, and bacteria were cultured with streak plate method. In this investigation, 62 bacterial isolates from different parts of tannery factory and 15 strains from Persian Gulf were isolated. The ability of salt-tolerant bacterial isolates were examined for the production of different hydrolytic enzymes. From 42 bacterial strains, isolated from tannery factory, 22 isolates were able to produce some of hydrolytic enzymes. In the case of bacterial strains isolated from Persian Gulf, 8 of 9 total bacterial isolates had capability for producing of hydrolitic enzymes. Results indicated that halophilic bacteria have the high potential to produce different enzymes and their production districted in presence of various concentration of NaCl salt.

Two distinct modes of cell death, apoptosis and necrosis can be distinguished based on differences in morphological, biochemical and molecular changes of dying cells. Apoptosis is the most common form of eukaryotic cell death. It is a physiological suicide mechanism that preserves homeostasis. It has been reported that dietary fibers such as pectins causes cell death either in vitro or in vivo. In this study the effects of the pectic acid (derived from apple) on the GH3/B6 cell death is investigated. Materials and methods: GH3/B6 cells were cultured in the Ham’s F12 medium enriched with 15% horse serum and 2.5% fetal bovine serum for 3 days. Then they were treated by various amounts of pectic acid in different periods (6, 24, 48 hours). Previous studies showed that bromocriptine is one of the apoptotic agents in these cells, so it was used as positive control. The cell viability was detected by MTT exclusive test. The nuclear morphology of cells was explored by florescent stains including Acridine Orange/Ethidium Bromide (AO/EB). In addition, percentage of necrotic and apoptotic cells were studied with TUNEL kit. MTT test has shown that different concentration of pectic acid in 24 h decreased GH3/B6 cells viability in a dose dependant manner. Furthermore, florescent staining and TUNEL test showed that pectic acid concentration from 100mg/ml up to 1mg/ml concentration can induce apoptosis in a dose dependent manner and in the higher concentration such as 2.5 mg/ml and 5 mg/ml can induce necrosis in these cells (p<0.001). According to our results it seems that pectic acid causes apoptosis and necrosis in GH3/B6 cells.

Results of many studies have shown that in animal and plant populations, naturally exposed to radiation there are genetic instability. In this study, our goal was evaluation of RAPD polymorphism in offspring (F1 generation) from parents exposed to acute (3Gy) and chronic (total dose was 37cGy) irradiation. RAPD method widely used for classification of breeds, lines, sorts and cultures and also drawing up phylogenetic maps. In the view of radiogenetic monitoring the positive property of RAPD method is possibility of rapid scanning of genome descendants irradiated parents and no prior genomic sequence information. Male CBA/lac and BALB/c mice and female hybrid (CBA/lac×c57/black) mice are used in study. The results of this experiment indicated that using this primers give the most variability of RAPD markers in offspring from male parents exposed to gamma-radiation (3Gy) 3 months before mating. We also observed increased level of DNA polymorphism in descendants of parents exposed to chronic gamma-radiation. Our results demonstrated that level of polymorphism in irradiated mice is 27-50% more than non-irradiated mice. Using this primer series (759, 760, M1 (761 and 763), 765 and M2 (766, 768, 769 and 775) made possible to receive significant increase in mean frequency of new bands in offspring's treatment group that allow us to use this system in future investigations for studying induction of genomic instability.

Plants offer a promising alternative to microbial fermentation and animal cell cultures for production of recombinant proteins, because of features such as high safety, low cost, post-translation modifications and high volume of production. In this report, recombinant cDNA of tissue Plasminogen activator was transformed to tobacco plants. This gene was expressed under the control of CaMV35S promoter and NOS terminator. Kozak sequence and KDEL signal were linked at amino and carboxy-termini of tPA gene, respectively. The constructed cassette pBI (tPA) was transferred to agrobacterium and the tPA gene was inserted into the plant genome by agrobacterium-mediated transformation. Transgenic plants were grown on selective medium and then transferred into perlite and soil, to obtain subsequent generation (T0). The transgenic plants were tested by polymerase chain reaction (PCR), RT-PCR and Western blotting.

Monascus is a microscopic fungus belonging to Eurotials order and due to its importance and extensive applications, such as pigment, flavouring and preservative agents production for foods and in drugs as cholesterol-lowering agent and also according to its worldwide distribution, we isolated and identified natives strains of this fungus for the first time in Iran. In this study, out of 122 samples collected from different sources such as flours, rice, soil, starch, fruits and slime, 4 conformed fungi strains were isolated using MEPAG culture medium in which two strains of the isolated colonies had capability for pigment production. After microscopic and macroscopic observation, the proper cases were isolated and identified by identification keys. To further confirm the identify of the two isolates, the PCR was applied for a rDNA specific region called ITS (Internal Transcribed Spacer) and was sequenced, that this method confirmed the genus recognition. The result of this research was isolation and identification of two Monascus species. Using standard taxonomic key, we recognized them as M. fumeus and M. purpureus.

The population structure of pikeperch Sander lucioperca was studied in the Iranian waters of Caspian sea and Aras dam lake using the morphometric and meristic characters. Samples were collected from the main fishing areas of this species in Iranian shores of Caspian Sea (Western and Eastern shores of Guilan) and also Aras dam lake. Twenty seven truss distances as well as eye diameter and interorbital width and also 13 meristic counts were measured on each individual. Univariate analysis of variance (One-way ANOVA) revealed significant differences with varying degrees between the means of the three samples for 13 standardized morphometric measurements and 6 meristic counts that showed nearly high significant differences between the three populations. Plotting discriminant functions 1 and 2 revealed a high discrimination between the samples of 3 areas. But for the meristic characters the amount of discrimination was low and the samples of 3 area showed a high overlap. The average of correct assignment of individuals into their original samples for morphometric and meristic characters was 89.5% and 67.5% respectively.

This survey was accomplishing during seven months (March-October 2007) on around of SABZEVAR region. The lizards captured on 7 one-ha plots (100m×100m), that based on topographic and vegetation change, Lizards were sampled by 2 methods. The first consist of padding and the second sampling method was accomplished with pit-fall trapping. Twenty pitfall traps were established in each plot and were placed at random-systematic within a plot. Over all, we capture 151 specimens that belong of 4 family, 8 genuses and 12 species. For measuring of the diversity we use Shannon-Wiener, N1, Simpson and Hill indexes, and for evenness measuring used the Camargo, Simpson and Smith &Wilson indexes, In addition, we use Rarefaction Method for equate of data and measure the species richness. Finally in regard with the results that derivatived by different indexes we found that, the relationship between altitude and species diversity is negative correlation but this relationship between altitude and lizard’s species evenness was positive. (diversity indexes): Shannon-Wiener (r=0.9, R2=0.806), N1 (r=0.91, R2=0.832), Hill (r=0.77, R2=0.59), Simpson (r=0.75, R2=0.56); (evenness indexes): Simpson (r=0.77, R2=0.57), Smith &Wilson and Camargo (r=0.8, R2=0.64). In addition, another negative correlation was be shown within altitude and species abundance (r=0.73, R2=0.53) and species richness (r=0.85, R2=0.73(.

The age structure and growth of Neogobius fluviatilis Pallasi were studied using 320 specimens from Madarsoo Stream, from 1997 to 1998 in Golestan National Park. Females made up 24.7% and males 75.3% of the individuals (p£0.05). The total length-weight relationships were W=0.004L3.32 and W=0.001L4.02 for male and female, respectively. The age data, derived from otolith reading. The result showed that 3+ was the oldest age group for both sexes. The most abundant ages was 2+ years, The age data were used to estimate the growth parameters of the Von Bertalanffy equation: L(t)=26.78 (1-e-0.1(t+1.776)) and L(t)=29.04 (1-e-0.1(t+1.472))for male and female, respectively. The results showed that there were significant differences in overall sex ratio between the males and females. The highest instantaneous growth rate was observed in 0+ to 1+ age groups and the growth showed down after 2+. The Pauly equation indicated a positive allometric growth model for both sexes.