نشریه یافته های نوین در علوم زیستی
سال دوم شماره 4 (پیاپی 6، زمستان 1394)

During the infection- while the xylem is colonized by the F. oxysporum f. sp. Lycopersici (Fol)- several effector proteins have been secreted into the xylem that suppress the plant’s defense response and enable parasitic colonization. So far, 14 effector proteins have been reported in Fol. However, there are no identified domains in their sequences. LysM effector proteins were identified in some plant pathogenic fungi and involved in sequestering chitin oligosaccharides. Here, considering the role of LysM effector proteins in plant-pathogen interactions, we searched for candidate effector proteins possessed Lysin (LysM) domains in the genome of FOL. Hence, the LysM domain was searched in the WGS data bank of Fol using Pfam tool and 17 proteins were identified. Two proteins, Fol-LysM1 and Fol-LysM3, were selected based on low molecular weight and present of signal peptide in their sequences. Prediction of the gene structures preformed using FGENESH tools and domain structures and effector characters including signal peptide, number and position of cysteine residues, disulfide bond connectivity and molecular weight of proteins were predicted. The entire nucleotide sequences of the coding region of their genes were determined by PCR and phylogeny of lysM effector proteins was studied. Furthermore, the domain organization of these proteins was compared with that of other lysM effector proteins. This is a first report of detection of lysM effector genes in Fol.

Human serum albumin (HSA) is the most abundant protein in blood plasma, which is responsible for 80% of blood pressure; it also acts as a carrier protein for many compounds in the blood such as drugs. In the present study, the interaction and side-effects of a newly-designed anti-cancer compound of isopentyl-glycine1, 10-phenanthroline Platinum nitrate on HSA have been investigated. In this investigation, the side effects, values of the number of binding sites and the association binding constants of new synthesized Pt(II) complex have been studied by different spectroscopic (fluorescence and circular diachronic (CD) techniques at different temperatures of 25 and 37 °C. The analysis of fluorescence spectra showed that the addition of the complex led to a significant reduction in the fluorescence spectra of HSA via quenching mechanism. Also, it can change the three-dimensional structure of tryptophan existing in the protein. The number of binding sites, the Stern-Volmer quenching constant and the association constant of the complex were calculated on the HSA protein. The analysis of circular dichroic spectra showed that the complex can change the regular secondary structure of the protein via reduction of α helical structure and increase of β sheet structure which indicates a decrease in the stability of the protein. According to the results obtained, it can be concluded that this new synthesized Pt(II) complex can bind to the main blood carrier protein (HSA) and change the secondary and tertiary structure of the protein which can be considered as the side-effects of this drug.

In this study, water stress was applied by polyethylene glycol at a concentration of 20 perecentage. To improve the resistance of the plants, the samples were treated by potassium nitrate at concentrations 5, 10, and 15 mM within 9 days. Changes in proline, total protein, photosynthetic pigments, carotene, anthocyanin, malondialdehyde, phenols, flavonols, flavonoids, soluble sugars and potassium ion were examined. The results showed that tobacco plants which had been exposed to drought used the accumulation of osmolytes such as proline, soluble sugars and potassium in order to balance their osmotic pressure. Drought stress also caused oxidative stress and increased the production of active forms of oxygen. As a result, non-enzymatic antioxidant defense system of tobacco plants including anthocyanins, flavonoids, flavonols and beta-carotene increased, which could be considered to be a major step for resistance to drought. The results also showed that the concentration of 15 mM potassium nitrate in particular, could significantly improve some of the harmful effects of stress and reduced photosynthetic pigments and proteins. Potassium nitrate could also bring down the MDA and beta-carotene levels to equivalent levels in control plants. As a result, it seems that using potassium can affect plant resistance to drought and plays an important role to reduce some harmful effects of stress.

Rhamnus L. is the genus of Rhamnaceae in Iran with nearly eight species. These species are used as valuable shrubs. This research was carried out in order to investigate the anatomical leaf. Samples from nine populations of Rhamnus pallasii and Rhamnus cathartica were taken. Treatment specimen cover various habitats from north of Iran, moreover herbarium samples were taken into account. The results presented two forms of epidermal cells such as Polygonal and irregular cells in addition, waved and straight anti-clinical walls were observed in R. pallasii subsp. pallasii and R. pallasii subsp. sintensii. Two types of stomata were demonstrated like anemositic and parasitic in two main species. Some characters e.g. thrichome, parenchyma, collenchyma layers were determined to finding some similarity among treatment specimen.

In this survey, anatomical characteristics of leaves in 35 populations belonging to 18 taxa of Scrophularia have been studied. Among 39 quantitative and qualitative anatomical characters, some have more suitable taxonomic value for differentiation of taxa, such as blade thickness, thickness of upper and lower cuticle of midrib, length of upper and lower palisade parenchyma of blade, thickness of lower epidermis wall of midrib, thickness of upper and lower epidermis of blade, rows of spongy parenchyma of blade, upper collenchyma type of midrib and the presence of idioblast. Finally, comparison of the results of the current study together with Grau’s (1981) results confirm the validity of 4 groups out of the 12 groups which he had introduced. As for the remaining groups, no noticeable concordance was found.

Tea was planted in Lahijan by Kashefalsataneh in 1930. The main concern about important commercial plants such as tea is the formation of ice crystals in low temperatures. This can damage the live cells leading to lowering the quality of the plant and eventually its death. Formation of reactive oxygen species (ROS) and oxidative stress is the result of various environmental stresses leading to freezing. Investigating the variations in any of these factors could help to understand the mechanism of freeze resistance in ever-green plants. The aim of the present research was to investigate lipid peroxidation, the presence of antifreeze protein and variations in the activity of some antioxidant enzymes, including superoxide dismutase (SOD), ascorbate peroxidize (APX) and catalyse (CAT) in tea leaves subjected to 20, 0, -2, -5 and -8°C in tea leaves from the north of Iran. The results showed formation of an antifreeze protein with MW of about 20 KD in response to cold stress. It was also found that the activity of SOD, APX and CAT increased in tea leaves due to cold stress. The activity of SOD increased down to -8°C. APX and CAT increased their activity down to -5°C. On the other hand, the lipid per oxidation factor, MDA, was also elevated in response to the cold stress.

It is clear that DNA concentration and biological detection devices have many applications in the fields of genetics and biotechnology. For this goal, some similar devices have been designed working with the laser light which the disadvantages of them are high prices and the use of significant amounts of sample volume. But this designed device which works with LED light has very cheap manufacturing cost. The amounts of DNA used in this device are very low, about a few micro-liters and measurement of small, fast and portable it is also the advantages of these devices. The Data recorded as voltage versus time and the Fourier transform the frequency domain. From the frequency curve, by using the Byrlambrt it is possible to obtain the relative concentrations of DNA, viruses and assays measuring DNA damage and many other applications. By use of this device, the concentration of DNA colored with three different pigments was measured.