نشریه دانش زیستی ایران
سال پانزدهم شماره 1 (بهار 1399)

Stress is mentioned as a common problem in daily life. Disrupting the homeostasis of metal elements such as zinc in the central nervous system, stress causes diseases or dysfunction of various tissues. Zinc plays an important role in the function of vital organs, especially the central nervous system. Disorders of zinc homeostasis in turn lead to the development or progression of diseases such as Alzheimer's, depression, learning disabilities, and ischemia. Zinc transporters (ZnT) and ZIP proteins maintain Zinc homeostasis in the live organisms. The aim of this study was to investigate the effect of acute motor restraint stress on the expression of Znt1, Znt2, Znt3, and Znt4 genes in the hippocampus of rats as one of the tissues with high zinc density. Adult male rats were divided into groups of control and stress. RNA was extracted from hippocampal tissue and changes in the expression of Znt1, Znt2, Znt3 and Znt4 genes were monitored by real-time PCR. The results showed that due to stress induction, Znt1 gene expression increased significantly and no significant changes were observed in the expression of other studied genes. Identifying those zinc transporter genes that are altered by stress can make it possible to find a cure for stress by regulating zinc levels in the body through Zinc-containing drugs.

Punica granatum L. (pomegranate), is among important horticultural plants which is cultivated in many parts of the world and appreciated for its fruit value and medicinal properties. Several pomegranate cultivars are cultivated in Iran which differs in fruit characteristics and agronomical features. In spite of economic importance of pomegranate cultivars, limited knowledge is available on genetic and cytogenetic peculiarities of these cultivars. Therefore, we aimed to investigate cytogenetically twelve unreported cultivars and also compile all available data on chromosome pairing, chiasma frequency and meiotic irregularities in 88 cultivars and carry on a meta analysis. We found all cultivars to have 2n = 2x = 16 chromosome number, but significantly differed in all meiotic features studied. Most of meiotic features studied were significantly correlated while PCA analysis revealed that characters like chiasma frequency and distribution as well as ring bivalents are associated to each other and differentiated the cultivars which were distributed towards longitude. Similarly, characters related to meiotic irregularities such as chromosome stickiness and anaphase failure differentiated the cultivars which were distributed toward altitude. PCA plot placed pomegranate cultivars in three major groups due to meiotic difference. Data obtained can be used in future conservation and breeding of pomegranate.

Urinary tract infection is one of the most important nosocomial infections that is often caused by catheterization. Europathogenic bacteria can potentially cause urinary tract infections by forming biofilms in catheters. The aim of present study was to investigate the formation of Klebsiella pneumoniae biofilm from catheter-associated urinary tract infection. The study was performed on 110 urine samples of patients who referred to the clinical laboratory of Milad Hospital, Tehran. Patients were divided into two groups with catheter-associated and non-catheter- associated urinary tract infections. Isolation and identification of Klebsiella pneumoniae were performed by biochemical tests and biofilm formation by plate microtiter method. 70 and 40 samples were related to catheter- associated and non-catheter- associated infections, respectively. 60% of Klebsiella pneumoniae isolates from associated with urinary tract infections due to catheterization were strong biofilm, 26.7% moderate and 13.3% weak. 33.3% of Klebsiella pneumoniae isolates associated with urinary tract infection without catheter formed strong biofilm, 36.6% moderate and 23.3% weak biofilm and 2 isolates did not form any biofilm. The use of catheters in hospitalized patients increases the risk of urinary tract infections, which depends on various factors such as the duration of catheterization, type of catheter, and ability to form a biofilm of uropathogenic bacteria. The power of bacterial biofilm formation during catheterization increases the risk of infection and leads to antibiotic resistance of isolates and lack of proper treatment of patients.

This article introduces the appropriate Persian equivalent for the two English terms Dendrocolous and Dendrophilous. According to the study and rootting of these terms in Greek and English and also the use of these terms in the field of biology and natural resources, the Persian term "Dar Zei" instead of Dendrocolous meaning "creatures that live or grow on trees". The Persian equivalent of "Dar roy" instead of Dendrophilous in the meaning of "plant growth on the tree", with these terms accurately, the technical concept conveyed by these terms, in English is also more accurately conveyed in Persian. On the other hand, the ability to understand and use different derivatives of these terms, such as verb and subject, etc., can be used better.

It is very important to observe hygienic principles in the production of mayonnaise, as a nutritious and popular product, as well as to prevent physical, chemical, microbial spoilage and thus prevent its quality reduction. In this study, we tried to evaluate the efficiency of extracting aqueous extract of chestnut fruit as a natural antioxidant. For this purpose, Samples of mayonnaise with different concentrations of the extract were prepared under treatments B1 (mayonnaise + 750 ppm sodium benzoate + 750 ppm sodium sorbate), B2 (mayonnaise + 400 ppm chestnut extract + 500 ppm sodium benzoate + ppm sodium + ppm) B3 (mayonnaise +800 ppm chestnut extract +500 ppm sodium benzoate + 500 ppm sodium sorbate) and B4 (mayonnaise + 1200 ppm chestnut extract). Chemical factors (acidity and peroxide number), microbial, and sensory factors (general acceptance) were examined for the 6 months (first day, the second month, the fourth month, and the sixth month).  The results showed that the extraction efficiency of the extract by the aqueous method was equal to 22.5%. According to the results, Chestnut fruit extract with benzoate and sodium sorbate significantly reduced peroxide and acid index in the samples (p<0.05). The antimicrobial effect of chestnut fruit extract is confirmed on a significant reduction in microbial population and shelf life of mayonnaise. Sample B3 was introduced as the superior treatment in this study by considering sensory factors (general acceptance).

Salmonellosis is the most important form of bacterial infection in humans and animals caused by the non-typhoid salmonella family. Salmonella infection is the most common cause of foodborne infections. One of the most important sources of Salmonella contamination is poultry and meat products. In the last two decades, the emergence of Salmonella resistant to common antibiotics has increased the problems of Salmonella contamination in meat products. Transmission of these resistant bacteria to humans makes the treatment process difficult and lengthy. The aim of this study was to determine the prevalence of Salmonella bacteria and tetA and tetB resistance genes from poultry stores in Zahedan. In this descriptive cross-sectional study, Salmonella isolates were isolated from 130 poultry stores in Zahedan based on standard methods published by OIE and FDA. The results of this study show that only 6.15% of the samples were Salmonella and 3.07% were Salmonella typhimurium strains. Examination of the frequency of resistance genes in isolated samples in the present study shows that in 50% of Salmonella isolates, none of the tetA or tetB resistance genes was detected, while in the other 50%, only the tetB resistance gene was identified. The presence of tetracycline resistance genes in Salmonella isolates suggests that the use of antibiotics in the poultry industry should be controlled and more carefully used to reduce the frequency of these genes.