IRANIAN JOURNAL OF BIOLOGY
Year:2011 | Volume:24 | Issue:3|Papers Count:20

Leber hereditary optic neuropathy (LHON) is an inherited form of bilateral optic atrophy and loss of central vision.  The primary cause of vision loss is mutation in the mtDNA however unknown secondary genetic and/or epigenetic risk factors are suggested to influence its neuropathology. In this study folate gene polymorphisms has examined as possible LHON secondary genetic risk factor in Iranian patients.  Common polymorphisms in methylene tetrahydrofolate reductase (MTHFR) (C677T and A1298C) and methionine synthase reductase (MTRR) (A66G) genes have been tested in 21 LHON patients and 150 normal controls. Strong linkages have been observed between LHON syndrome and C677T of the MTHFR (P<0.001) and A66G of the MTRR (P<0.001) genes.  However, no significant linkage was found between A1298C (P=0.69) of the MTHFR gene and LHON syndrome.  This is the first study that shows MTHFR C677T and MTRR A66G polymorphisms play role in the etiology of LHON syndrome. This finding may help in better understanding of mechanisms involved in neural degeneration and vision loss of LHON and better treatment of patients.

In this project, an appropriate indigenous Bacillus strain for xylanase production was isolated from cotton farm (Iran- kashan). According to evaluation by preliminary and secondary screening procedures, the competency of produced xylanase by this strain was confirmed. pH and temperature of enzyme activity in elevated pH and temperature ranges was assessed by measurement of released amounts of reducing sugar method. Optimum pH 9 and temperature of 55 oC for xylanase activity for this strain determined as optimum points. 16S rRNA sequencing analysis identified the isolate, as a strain of Bacillus mojavensis. Optimization step for screened Bacillus mojavensis strain, as a superior strain in the course of enzyme economical production process was performed in the presence of molasses, bagasse, wheat bran, oat husk and rice straw, and enzyme production level was evaluated. Finally, xylanase production level from 194/68 IU/ml, under non-optimized culture condition, increased to 302/466 IU/ml in optimized fermentation condition. Increase in cost- effective xylanase production by lignocellulosic wastes (Oat husk as optimum carbon source), strain ability to ferment such wastes, production of high level of xylanase, and optimum enzyme activity in alkaline pH and elevated temperature, all reveal the superiority of this Bacillus as a candidate for industrial-scale economical production of xylanase.

Agrobacterium–mediated transformation and regeneration of two Iranian citrus genotypes, including Minou (Citrus sp.) and Darabi (Citrus grandis) was carried out in optimized conditions developed for most of citrus species. Additionally the effects of cocultivation period and concentration of Benzyl aminopurin (BAP), notably affecting transgenesis, were also evaluated on a set of 50 explants. Internodal stem segments of 1 cm length from 6–8 month old greenhouse grown seedlings were cocultivated with A. tumefaciens strain C58C1 (GV 3850) caring pBI121 plasmid with introduced b–glucoronidase (uid A) gene. A 72 hr cocultivation on a medium rich in BAP (5 mg/l) markedly improved transformation frequencies as it increased dividing cells competent for transformation at the cut ends of explants. In these conditions, a transformation efficiency of 34.8 % and 30.1 % was achieved for Minou and Darabi, respectively, as surveyed by GUS expression biochemical assay and confirmed by PCR amplification of uid A gene. The transgenic explants continued to growth in shoot induction medium and produced 5–10 cm shoots competent for grafting. This is the first report of transformation and regeneration of Iranian citrus genotypes.

Datura innoxia (solanaceae) has pharmaceutical valuable tropane alkaloids. Atropine and scopolamine are two major tropane alkaloids of this plant. In this study to increase of tropane alkaloid production, the influence of putrecine, a precursor of tropane alkaloid biosynthetic pathway, was determined on in vitro regenerated plantlets of Datura innoxia. To produce explants including single nodes with auxiliary buds, seed embryos were cultured in MS medium. To optimize the culture conditions, the explants were cultured in MS media with 0, 0.5, 1, 1.5 and 2 mM of IAA and BA, as plant growth regulators. For putrenine treatments, the explants were cultured in MS media containing 0.01, 0.02, 0.04 mM of putrecine. Results showed significant differences in shoot growth between media with different concentrations of IAA and BA. By increasing the putrescine concentrations, atropine and scopolamine contents in shoots and roots of treated plantlets were significantly increased.

Atropa belladonna, a member of Solanaceae family, is a very important pharmaceutical plant. Its roots are composed of significant amount of important alkaloids atropine and scopolamin. In this study the effect of different concentrations (0, 0.01 and 0.1 mM) of salicylic acid as a signal molecule was evaluated on gene expression levels of hyocyamin 6-b hydroxylase (H6H) and putrescinN-methyl transferase (PMT) in the hairy roots and plantlet. Expression level of these genes was evaluated by semi quantitative RT-PCR. The results showed that different concentrations of salicylic acid have different effects on gene expression levels. Isozymes of PMT and H6H in different organs and in response to the concentrations of salicylic acid were differentially expressed. H6H and PMT2 genes expression were increased at 0.01mM in the hairy roots. Expression of PMT2 in the roots was increased at 0.01mM. But the level of gene expression in shoot was not significantly affected.

Drought stress is the second important constraint of yield in chickpea after disease. In order to study the effects of drought on total dry weight, seed yield, chlorophyll content, relative water content and amount of proline and soluble sugars accumulation of 6 Kabuli chickpea genotypes including Arman, Jam, Hasham, Flip93-93 (Azad) , ILC482 and ILC1799, a experiment was conducted during the 2007 at experimental greenhouse of the agricultural faculty of Bu-Ali Sina University. The experiment was established using a factorial completely randomized design with three irrigation levels (100, 50 and 25% available water). Assessment of the results indicated that total dry weight, seed yield, chlorophyll content and relative water content were significantly decreased by reduction in available water from 100 to 50 and 25%. The detrimental effects of reduction in soil available water on chlorophyll a content was more than chlorophyll b. Reduction in available water from 100 to 50 and 25% decreased chlorophyll a content 31 and 43 percent, while the reduction of chlorophyll b content in that range was 16 and 38 percent, respectively. Water deficit stress caused an increase of proline and total soluble carbohydrates contents, so that their concentrations at 25% AW increased to 32 and 2 times, respectively. Proline accumulation was mainly different from changes in soluble sugars concentration, total dry weight and relative water content.

In this study, in order to study genetic diversity in the accessions of Aegilops tauschii from Northern area of Iran, 86 accessions of this species selected and evaluated using SSR markers. Ten SSR primer pairs were applied for genotyping assays. A total of 140 alleles were detected across all loci, ranging from 9 to 25 alleles per locus, with an average of 15.5 alleles per locus. The polymorphic information content (PIC) values of the loci ranged from 0.16 (WMS111) to 0.38 (WMS114). Genetic similarity calculated from the SSR data ranging from 0 (many genotypes) to 0.88 (two genotypes from Ghazvin and Gilan) with an average of 0.101. Cluster and PCA analyses could not separate accessions, indicating that there is high genetic diversity among accessions.

For achievement to sustainable development and conservation of natural ecosystems and their biodiversity, study on ecological factors and their effects is necessary. Regarding to topographical condition of northern forests of Iran, altitude is an important ecological factor controlling many other dependant variables. In order to, study on this factor 84 sample plots with 400 m2 area were taken by systematic - random sampling method in Sardabrood forests of Chalous. Plant species were identified and their coverage was recorded on the basis of Braun – blanquet scales within every sample plot. Site altitude were divided to five classes including 100 – 400, 400 – 700, 700 – 1000 and 1000 – 1300 m a.s.e. in order to investigate of plant diversity in different altitudinal classes. Heterogeneity indices including Simpson, Reciprocal of Simpson, Shannon and evenness indices including Camargo, Simpson, Smith and Wilson were calculated using Ecological Methodology software. Analysis of variance for heterogeneity and evenness indices showed that the values of these indices had significant differences (P<0.01) in different altitudinal classes. The maximum and minimum of heterogeneity indices were founded in fourth and first altitude classes, respectively. The highest value of evenness indices observed in fourth altitude classes and the other classes showed no significant differences. The highest species richness was observed at first altitudinal class and the lowest one was devoted to fourth altitudinal class.

In order to ecologically investigate Cercis griffithii L. species and recognize its existing sites in West of Iran, boundaries of this species were located on the topographic map and 89 plots with areas of 1200 square meters were implemented. The vegetation type (including tree and shrub species), soil type, and physiographic factors of the region were determined. Using multivariate analysis, four sites were recognized. Results showed that Ilam region has two sites which the first site includes Cercis griffithii L. that has a positive correlation with Silt, pH, Mg, K, Ca, and P that together form a group. Two sites include Quercus brantii L. that has a positive correlation with Clay, Silt and organic matter that together form a group. Similarly, Paveh region has two sites. Here, like Ilam region, the first site includes Cercis griffithii but this Cercis griffithii L. had a positive correlation with Clay, Silt, pH, EC, CaCo3, C-O, N, Mg, K, and Ca that together form a group. Two sites include Pistacia atlantica Desf. subsp. mutica But this Pistacia atlantica Desf. subsp. mutica had a positive correlation with Silt, organic matter, N, K, Ca and P that together form a group. According to the results of this study, it can be concluded that Cercis griffithii species in regions with soil types of high amounts of clay, silt, C-O, Ca, and K, are located in steep lands with north directions. Therefore, in order to plant this species in green area, reclamation and enrichment of this species in its natural site and other dry and semi-dry regions requirements of this species must be considered.

In this survey flora of Ghorkhood area has been studied. Ghorkhood area locate in North Khorasan province. Its geographical position is 56o 08' E to 56o 39' and 37o 20' N to 37o 31'. Plant species sampling was carried out in according to the beginning of growth season. Then collected plants were identified by using of indispensable references. In these study 31 families, 118 genera and 196 species were identified. The largest family is Poaceae with 17 genera and 32 species. The life form of plant species was determined by using of Raunkiaer's method and they are including 11.2% phanerophytes, 16.8% chamaephytes, 43.9% hemicryptophytes, 8.2% geophytes and 19.9% therophytes. As most of the species are perennials and confirms the species adaptabilities to climatic and edaphic conditions of the studied area.

Bothynoderes obliquefasciatus (Menetries, 1939, Coleoptera: Curculionidae) is a major pest of sugar beet in the warm and dry regions of Isfahan province. The adults are attracted to different hosts such as Chenopodium album (Linnaeus, 1753, Chenopodiaceae), Amaranthus sp. (Amaranthaceae) and Salsola sp. (Salsolaceae) in the absence of sugar beet.  Investigation on preferences for attraction to host plants is important for bioecological control of insects. Unfortunately, conventional insecticides do not control the pest effectively. Thus it is very important to look for a new method rather than insecticides, for example, trap crops. Host plant preferences for attraction, attraction to extracts of these hosts by adult B. obliquefasiatus, and the amount of feeding on different sugar beet varieties were determined in choice – experiments in laboratory, green house and semi field conditions. We displayed the amount of feeding on different sugar beet varieties and analyzed data from all experiments provided in statistical tables. The results showed that considerable variation exists in attraction and feeding preferences of the sugar beet weevil among different sugar beet varieties and some weeds. In all experiments, adult insects attracted and fed on the IC1, Amelie and Rizofort varieties rather than the others. The attraction to and feeding from V7233 was the least. Adult insects preferred Chenopodium album for feeding and they used other weeds as shelter.

During a faunistic survey on mites associated with Pistachio trees which was conducted in 2007-2008 in Mahvalat region and campus of Ferdowsi University of Mashhad, specimens of Shevtchenkella recki (Bagd.) were collected for the first time. The morphological characters of this species and closely related species are given. By this report, the number of eriophyid species on Pistachio trees reached to three. Some important morphological characters of three eriophyid species found on Pistachio trees in Iran are compared.

One of the most interesting phenomenons among some animals is color polymorphism between different populations of the same species. This variation in color is likely due to the adaptation of animals with the environment in order to escape from the predator or nearing to their prey. Here, we investigated this phenomenon in Rana ridibunda which is found throughout the Iran. We demonstrated that there are seven different morphs among populations of this frog. Of these, frequency of the morph 3 is more common than the others. We have also shown that there is no clear relationship between the gender and morphs and it seems these have been evolved independently.

The effects of some abiotic factors (pre-incubation condition, floating in 1% NaOCL, temperature and photoperiod) was investigated on the hatching response of Daphnia similis ephippial eggs collected from live food ponds in cultivation centre of Gorgan. After isolation, the eggs were kept in dry and wet conditions at 4oC for 2 months in darkness. Following the pre-incubation period, the eggs in each group were subdivided into 2 parts and treated with1% NaOCL and distilled water. The effect of temperature levels (20oC, 25oC and 30oC) and photoperiod levels (12L: 12D and 24L: 0D) were identified on the hatching of eggs in AdaM medium during 15 days. Results indicated that the exposure of wet eggs of Daphnia similis to 12-hour photoperiod and 20oC after soaking in 1% NaOCL, increased the maximum rate and speed of hatching. These ephippial eggs significantly reacted more rapidly while keeping in wet condition at 20oC but no significant difference (P>0/05) in shortening time until hatch was observed among different levels of photoperiod and floating in 1% NaOCL.

Faunal study of Odonata of Fars province began for the first time in Iran at the department of biology, Shiraz University in 2002 (1380). According to the accessible references, no study on larval stage of Odonata of Iran was found till the time of this research. A total of 332 larvae, 229 of the suborder dragonflies (Anisoptera) and 103 of he suborder damselflies (Zygoptera) were collected in a year sampling. All these collected larvae are 14 genera, 9 belong to Anisoptera and 5 to Zygoptera which identified for the first time in Iran. Description of the full-grown larva of a species from genus Anax and a provisional key to the families and the last larval instar of the known 14 genera is given.