نشریه یافته های نوین در علوم زیستی
پیاپی 2 (زمستان 1393)

Recently، concern over environmental and health effects of massive use of antibiotics has led to the growth of bio-control agent application. Poly-β-hydroxybutyrate (PHB) is a natural polymer that can be depolymerized into water-soluble short-chain fatty acid monomers and acts as a microbial control agent. In this study، the effects of the addition of PHB to the diet of Siberian sturgeon fingerlings by 2% and 5% were investigated. Community Level Physiological Profile (CLPP) was used to analyze anaerobic bacterial metabolic diversity in Siberian sturgeon fingerlings hindgut by using Biolog™ Ecoplate microplates. The results indicated that PHB increased metabolic activity in anaerobic bacteria in sturgeon hindgut. Also Lorenz curve and the Shannon index of Biolog™ Ecoplate data revealed that anaerobic metabolic potential of the bacterial community was different in the PHB-treated fishes compared with the control situation.

Microbial analysis of ground water, as the sole supplying water source in many areas, must be evaluated. Because the treatment of water cannot remove all pathogenic bacteria leaked from domestic wastewater, bacterial analysis of Bojnourd groundwater sources was performed. For this reason, membrane filter (MF) technique and Most Probable Number (MPN) method were used to evaluate the microbial quality of the water. Escherichia coli (E. coli) and Enteroccocus faecalis (E. faecalis) were traced as excremental indices. E. coli was detected from three out of six stations and E. faecalis was only isolated from one station. Although molecular techniques are very rapid and exact methods for detection of microbial community and can identify ‘Viable But Not Cultivable’ (VBNC) bacteria, they are unable to make a distinction between living and non-living microorganisms. By means of a standard technique, it is possible to study living and metabolically active microorganisms. Due to the detection of E.coli and E.feacalis in some stations the sanitization of groundwater must be revised to lessen the microbial population in this groundwater.

In this research, plant morphology and pollen micromorphology of 14 populations of 3 species belonging to two sections Plethiosphace and Hemisphace of Salvia genus in Iran were studied. In the morphological study 25 quantitative and qualitative characters were investigated and the results clearly separated the species into two groups. The pollen grains from the herbarium specimens were prepared by acetolysis method and then 4 quantitative characters were examined by light microscopy. Data was processed by principal component analysis method. Results indicated that although the pollen grains in the section were comparatively homogenous and all of them were 6-colpate with reticulate ornamentation, a considerable variation in the quantitative characters studied turned out to exist. However among the characters studied, equatorial and polar diameters of pollen grains were the most significant and based on these characters the members of these sections can be divided into two groups.

Saponins are secondary metabolites that are found in many plants and some animals. These compounds are high molecular weight glycosides, consisting of a sugar moiety linked to a triterpene or steroid aglycone. Many saponins have detergency properties and give stable foam in water. The genus Silene L. with more than 700 species is one of the largest genera of the family Caryophyllaceae mainly distributed in northern hemisphere. Saponins are one of the important secondary metabolites in the members of the genus. Quantitative and qualitative study of the saponins in the aerial parts and roots of three Silene species, namely S. ginodioica Ghaz. subsp. Penducularis (Fenzl ex Boiss.) Melzh., S. spergulifolia (Willd.) M. Bieb. and S. swertiifolia Boiss. were carried out by spectrophotometry and TLC methods. In this study, 5 fractions were obtained from each plant part and in both parts of the three species, fraction 1 contains the highest amounts of saponins. On the other hands, root extracts have high amounts of saponins. In addition, thin layer chromatography (TLC) of the extracts revealed some saponins spots with different Rf.

Effects of ozone depletion and increase of UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B radiation on Melissa officinalis L. as well as the impact of salicylic acid and magnetic fields in the reduction of harmful effects of radiation on plants. The Melissa officinalis L. plants were treated with 28 ± 2 Cº for approximately 60 days. The light intensity was 150 µ E mˉ² Sˉ¹ and the light/dark regime was 16/8 h. UV-B treatment was applied after the six-leaf stage for a period of 15 days and 20 min every day. Salicylic acid (1mM) was daily sprayed on the plants after the six-leaf stage for one week. Magnetic field treatment was applied for an hour with intensities of 0, 40 and 85 mT. The results indicated that the UV-B radiation led to reduction of root and shoot dry and fresh weights, and root and shoot elongation. The radiations also reduced the content of photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid), sugar and soluble proteins. The phenylalanine ammonia-lyase activity and UV-absorbing content compounds increased under the effect of UV-B radiation. The results showed that treatment with salicylic acid and magnetic fields reduced damages to the plant due to UV-B radiation.

Pedicularis L. (Orobanchaceae) is a large hemiparasitic genus, distributed mostly over boreal and arctic-alpine regions of the northern hemisphere. In the present study 9 species of the genus that are reported in flora of Iran, were undertaken for stigma morphological study and numerical analysis. The stigmatic surface is even in P. pycnantha and P. wilhelmsiana, is expanded into a subspherical shape in P. cabulica, P. caucasica, P. rechingeri, P. sibthorpii, P. condensata and P. strausii and is conical form in P. rhinanthoides. To determine the relationship between species, numerical analysis was carried out using 45 quantitative and qualitative morphological, anatomical and palynological characters. UPGMA and PCA dendrograms were drawn. According to the results some characters such as the thickness of pericarp, the thickness of spongy parenchyma, the length of stem, the thickness of bark, the thickness of stem and the length of midrib are the most variable, and can be used for identification and determination of relationship between species.

Although there is extensive literature on different aspects of floral structure and embryology in Ranunculaceae, the distribution of developmental studies on the family is inharmonic. Studies on some genera are extensive, but others have been less extensively investigated or some may have remained unstudied. This research is an attempt to study the developmental stages of ovule in Consolida orientalis. The flowers and buds in different developmental stages were sectioned at 7-10 μm with a microtome. Staining was performed with hematoxylin and eusine. The sections were studied by means of a light microscope. Results indicated that ovules are anatropous, bitegumic and crassinucellate. The megaspore tetrads are linear or nonlinear. The development of embryo sac belongs to the Polygonum type, but the presence of Allium type was also abundant in other species of this family. On the contrary to the common Polygonum type, the antipodal cells are large, persistent, and highly polyploid and remain uninucleate. They penetrate the embryo sac under the pressure provided by postament degenerate in the cellular stage of endosperm.

Cholestasis caused by the excessive accumulation of bile within the liver, due to intrinsic or extrinsic factors. Cholestasis side effects are associated directly or indirectly with the reduction of bile flow and the confinement of materials related to bile secretion (such as bile acids, bilirubin, and cholesterol). On the other hand, some factors such as opioids, alkaline phosphatase, endotoxin and nitric oxide increase in blood, which could cause tissue damage. Since water intake reduces during cholestasis and hypothalamic nuclei such as paraventricular and supraoptic nucleuses are involved in the regulation of body water; Therefore, in this study, the histopathological changes of hypothalamic nuclei were evaluated. Male Wistar rats weighing 200–250 g were randomly divided into three groups. Three sets of seven groups were unoperated control, sham-operated and bile duct-ligated rats. The tissue samples were analyzed using histotechnique and light microscope. Brain tissue necrosis in paraventricular and supraoptic nucleus in cholestatic rats increased, but in the sham and control rats no changes were observed and also cholestasis caused wrinkle chromatic nuclei and increased thickness of hypothalamic nuclei. Because endotoxin causes tissue trauma, it is likely increased endotoxin may leads to tissue changes in the brain.