Progress in Biological Sciences
Volume:6 Issue: 1, Winter and Spring 2016

In this paper we introduce a stochastic optimization method based on a mixed Bayesian/frequentist approach to a sample size determination problem in a clinical trial. The data are assumed to come from a nor- mal distribution for which both the mean and the variance are unknown. In contrast to the usual Bayesian decision theoretic methodology, which assumes a single decision maker, our method recognizes the existence of three decision makers, namely: the company conducting the trial, which decides on its size; the regulator, whose approval is necessary for the drug to be licensed for sale; and the public at large, who determine ultimate usage. Moreover, we model the subsequent usage by plausible assumptions for actual behaviour. A Monte Carlo Markov Chain is applied to nd the maximum expected utility of conducting the trial. Sample size determination problem is an important task in the planning of trials. The problem may be formulated formally in statistical terms. The most frequently used methods are based on the required size, and power of the trial for a specifed treatment efect Several authors have recognized the value of using prior distributions rather than point estimates in sample size calculations.

Human cytomegalovirus (HCMV) causes persistent infection in humans and severe diseases in fetus and immunocompromised individuals. Although HCMV is not currently implicated in human cancer, emerging evidence suggests that HCMV infection might be specifically associated with some human malignancies including glioma. Glioma is one of the most common brain tumors affecting children and adults. In this study, we used Real-Time (RT) PCR and immunohistochemistry techniques for detection of HCMV infection in glioma brain tumor biopsies. Paraffin embedded tumor tissues were obtained from patients who had been diagnosed with glioma. After designing of specific primers for the HCMV US28 region, a RT-PCR method was developed for HCMV DNA detection. Immunohistochemistry was performed on the same samples by using monoclonal antibodies specific for immediate earlyprotein (IE)-72 and IE 86 protein of HCMV. The results of RT-PCR on 4 of 18 patients (22/2 %) were positive. Two of the patients with HCMV positive RT-PCR results, passed away. Seven patients (38.8%) were positive with the IHC assay. It was also shown that in patients with higher grade of glioma, higher level of positive cells was observed using IE72 and IE 86 antibodies. Considering the results and controversies associated with reports from other regions of the world, a more comprehensive study using this and other diagnostic methods are suggested in Iranian patients with glioma.

The vasodilator response of nitric oxide (NO), hydrogen sulfide (H2S) and sulfur dioxide (SO2) were studied to determine the significance of the actions and interactions of these gasotransmitters for controlling aortic tone in rats. The isometric tension of five separate sets of experiments was recorded. Sodium nitroprusside (SNP; NO donor), sodium disulphide (Na2S; H2S donor), SO2 derivatives and their paired combinations were added to phenylephrine (PE)-induced contraction during the peak value. Then maximal relaxation rate was calculated four times at 5 min intervals. Tetraethylammonium (TEA) and Glibenclamide (GLIB) were applied for investigating the molecular mechanism of the gasses. While, in a separate set of experiments, we used either L-Arginine (L-Arg), L-Cysteine (L-Cyst) or L-nitroarginine methyl ester (L-NAME) before applying gasotransmitters. Highest and prolonged relaxation rate were recorded when SNP was combined with SO2. The combination of Na2S and SO2-induced vasorelaxation was blocked by TEA and GLIB pretreatments. L-Cyst decreased relaxation compared to SNP and vice versa to SO2 induced vasorelaxation. L-Arg markedly attenuated relaxation responses of Na2S and SO2 derivatives. Also, L-NAME delayed relaxation compared to Na2S and SO2. These results suggest that exogenous paired combinations of H2S, NO and SO2 will enhance and elongate the rate of aortic relaxation. Meanwhile, preincubation of aortic rings with precursors attenuate the dilatory effects of exogenous studied gases.

Medical polymers, such as urinary catheters are widely used biomaterials. One of the main problem for using the urinary catheters is biofilm formation on their surface, when they are used in a long time in the body. Virulence and pathogenicity of Staphylococcus epidermidis is often enhanced when growing as a biofilm. Many techniques have been presented to reduce the biofilm formation by surface modification. One of the most revolutionary techniques allowing such surface modifications is the plasma surface modification. In this work, plasma effects on S. epidermidis biofilm formation on urinary catheter surface have been investigated. Plasma was produced in a Pyrex glass tube containing nitrogen with pressure 1.6×10-1 Torr for plasma treatment of a catheter surface. Discharge voltage was about 1.2 kV and current was 150 mA. Each set of plasma treated catheter samples was inoculated by cultivation of S. epidermidis on 50 ml of Tryptic soy broth medium in the shaking incubator for 48 h at 37°C and 100 rpm. Then, amount of biofilm formation on the surface of polymer were assessed by crystal violet binding assay and sonication method. The results of these experiments indicated reduced biofilm formation on the modified surface around 50-60% compared to non-modified surface. This study shows that plasma surface modification can be used to reduce biofilm formation on medical polymers such as urinary catheter.

Identifying genes underlying complex diseases/traits that generally involve multiple etiological mechanisms and contributing genes is difficult. Although microarray technology has enabled researchers to investigate gene expression changes, but identifying pathobiologically relevant genes remains a challenge. To address this challenge, we apply a new method for selecting the disease-relevant genes from a published microarray dataset. The approach is comprised of combination of fisher criteria, SAM (Significance Analysis for Microarrays), and GA/SVM (Genetic Algorithm/ Support Vector Machine). To get rid of noisy and redundant genes in high dimensional microarray data, the Fisher method is used. SAM technique is utilized and different subsets of highly informative genes are selected by GA/SVM which uses different training sets. The final subset, highly informative genes, is achieved by analyzing the number of times each gene occurs in the different gene subsets. The proposed method was tested on microarray data of Alzheimer’s disease (AD) and the biological significance of identified genes was evaluated, and the results were compared with those of previous studies. The results indicate that the proposed method has a good selection and classification performance, which can produce 94.55 of classification accuracy by use of only 44 genes. From biological point of view, at least 24 (55%) of these genes are Alzheimer associated genes. Analysis of these genes by GO and KEGG led to identification of AD-related terms and pathways. These genes can act as predictors of the disease as well as a mean to find new candidate genes.

Ghrelin is an orexigenic peptide synthesized mainly by stomach and hypothalamus. Ghrelin decreases secretion of thyroid hormones. Testosterone is an esteroidogenic hormone that exerts stimulatory effects on Hypothalamus-Pituitary-Thyroid (HPT) axis activity. The aim of the present study was to investigate the effect of interactions between the central injection of ghrelin and testosterone on mean plasma thyroid hormones concentration. Twenty male Wistar rats (200-250 g) were randomly divided into four groups. The groups received saline, 5 nmol ghrelin, 1 μg testosterone and simultaneous injection of 5 nmol ghrelin and 1 μg testosterone in third cerebral ventricle in volumes of 3 μl. Blood samples were collected one day before injection and until 12 hours after that. Mean plasma thyroid hormones concentrations were determined by radio-immunoassay (RIA). The results indicated that testosterone significantly increased the mean plasma concentration of T3 and T4 hormones after injection compared to before injection, whereas ghrelin significantly decreased the mean plasma concentration of T3 and T4 compared to before injection. The results demonstrated that ghrelin significantly decreased the stimulatory effect of testosterone on mean plasma T3 and T4 concentrations.

The objectives of this study were to clarify whether the wild yeast isolated from fruits and humus is suitable for bread making. Using colony PCR, assimilation of carbohydrate and 18S rRNA sequencing, seven strains from among 70 samples were identified as Saccharomyces cerevisiae. The ethanol and CO2 production by the 10-2 wild yeast strain were highest among the strains. The pH and utilized glucose of all strains were pH 3.00-3.60 and 99.99%, respectively. The total acid content of the 9-3 culture was the highest (82.7 mg/100 ml) among the seven strains. The acetic acid contents of 9-3 and 10-2 cultures were 56.8 mg/100 ml and 56.3 mg/100 ml, respectively. Our finding showed that the 9-3 and 10-2 strain isolated from fruits have abilities of fermentation suitable for bread making.

Actinomycetes are a source of a broad variety of secondary metabolites with diverse biological activities, such as antifungi, antibiotics and antitumorals; many of which have been developed for clinical use. In this study, 34 actinomycetes from untouched soils were isolated from Alborz Province-Iran. Evaluation ofantifungal and anti bacterial activities of these isolates, demonstrated the capability of the isolates to inhibit the growth of fungi and bacteria using agar well diffusion method. Moreover, the ethyl acetate and ethanol extracts of an isolate were also tested against Staphylococcus aureus (MRSA) and their inhibited zones were measured. 53% of isolates were active against at least one of the seven tested pathogens and 32% of actinomycetes were active against tested pathogenic fungi. Some of the actinomycetal isolates had shown strong antifungal and antibacterial activity which promises a good source of novel antimicrobial agents. As a case, isolate act-3 was selected for its high antimicrobial activity against MRSA. These results suggested that actinomycetes from Alborz Province have a good potential for the production of biologically active compounds.

Effects of different concentrations [0, 1, 5, 10, 20 and 40 mgL-1] of Fe3O4 and CuO nano-particles (nFe3O4 and nCuO) were investigated on sulforaphane (SFN) production level in 7-day-old seedlings of Lepidium draba at different time intervals (8 and 16 hrs). According to the results, the influence of the particles on SFN content depends on nano-particle (NP) concentrations, time of treatment as well as chemical nature of NPs. The SFN content was significantly increased in treated seedlings with 5 mgL-1nCuO and all nFe3O4 concentrations as well as nFe3O4-treated callus after 8 hrs. However, by the increasing treatment time to 16 hrs, no significant changes on the SFN content were seen compared to the control. Furthermore, activity of peroxidase was also significantly promoted in treatment with both NPs (especially at higher concentrations) after 8 hrs and drastically decreased after 16 hrs. On the other hand, seed germination as well as the root and shoot length (except root length in treatment with nFe3O4) decreased compared to the control when seed germinated and plant growth in presence of both NPs for 7 days. Totally, these observations can be attributed to induce oxidative stress by NPs as a subsequence of their uptake by the plant. The increment in production of the phytochemicals through nano-metals treatment (nano-elicitation), opens an opportunity for induction of beneficial phytochemical content.

The anther, pollen and ovule development in Achillea tenuifolia were studied with a bright field microscopy. Results showed that the anther is of tetrasporangiate type and the anther wall is composed by four layers: an epidermis, an endothecium, one middle layer and a tapetum layer. Tapetum is of secretory type and its cells showed polyploidy. Pollen tetrads were tetrahedral, microspores were very irregular and contained large amounts of starch at the time of dispersion. Pollen grains were generally tricolporate, and in some cases were tetracolporate or even pentacolporate with spines on surface. The size of the pollen grains varied and ranging from 18-42.5 μm at the polar axis and from 16.5-35.5 μm at the equatorial axis. Ovule is anatropous, unitegmic and tenuiucellate. The archesporium may consist of one or more archeosporial cells, but only one of them undergoes meiosis, forming a linear or T-shaped tetrad. A 7-celled embryo sac is formed corresponding to the Polygonum type. Embryo sac is very tiny at the beginning of its development, its size was increased considerably at late growth stages. The relationship between Asteraceae, Calyceraceae and Goodeniaceae are discussed but based on embryological evidence, Goodeniaceae appear to be the putative sister group of Asteraceae. To understand more exact relationships within the order Asterales, embryological studies are recommended.

An efficient DNA isolation protocol specifically modified to get pure quality DNA required for molecular studies has been reported in this paper. Some aquatic plants (Potamogeton spp., Ceratophyllum demersum and Myriophyllum spicatum) were used for the study. The protocol developed will be useful in getting high and pure DNA. Instead of using the available DNA extraction kits, this protocol can be used to get pure quality DNA, free from proteins and polysaccharide compounds. The absorbance rate A260/A280 was 1.92 ± 0.069 and A260/A230 was 1.73 by spectrophotometer and NanoDrop machines which showed the sample genomic DNA is pure, free from contaminant proteins and polyphenolics/polysaccharides compound. The highest concentration of DNA was 640 ± 340.58 ng/μl when measured at 260 nm. When we run on agarose gel also, the isolated DNA gave a clear and sharp band. Thus, the DNA does not need any additional purification before proceeding for molecular analysis of the isolated DNA samples. This protocol is very simple and economical which will find wide applications in genomic studies of aquatic plants.

Large and diverse genera, such as Silene need more reliable morphological traits for the credible identification and delimitation of the species. Despite the fact that the type of indumentum among the species of Silene had been addressed in most available revisions, monographs and floristic studies, the trichome-based features and their adaptational importance have not been investigated explicitly. In the present study, the trichomes of annual species of Silene in Iran are studied. Beside other floral traits and vegetative features, the presence, distribution and mixture of the glandular and eglandular trichomes on stems, leaves, inflorescence axes, pedicels, anthophores, inner and outer surfaces of calyces, petals and styles are proved to be of diagnostic importance in Silene. Indumentum of the inner calyx among the studied species is investigated here for the first time. An identification key is performed mainly based on indumentum features. In addition, a putative trichome-based defense strategy is proposed in the examined species.