Effects of fertilizers on plant diversity,density, and uniformity in Golestan rangelands

One of the management operations in rangeland ecosystems for pastures restoration and improvement is fertilizer application. This study was designed to investigate the effect of fertilizer (50 kg/ha urea and ammonium phosphate fertilizers) on species diversity changes in a 100-ha experimental field of Salmechal Rangeland, Golestan Province. Plant species mean canopy cover was recorded using a 50-m² sampling plot. Statistical analysis was performed using Excel 2007 and PAST software. Fertilizer application increased the number of species present in the region from 21 to 51 and the plant families from 11 to 23. The forbs had the highest proportion (54.91%) and bushes and shrubs had the lowest percentage in the region. Fertilizer application increased plant diversity, uniformity, and coverage of the grasses. There was a significant difference (p < 0.01) between the grass and forbs coverage before and after fertilizer treatments. The results showed that the biological and physiological growth periods of the annual and perennial plants were significantly different before and after fertilizer application (p < 0.01). Also, their proportion in rangeland plant species composition significantly increased after fertilizer application.     

Plasma cortisol changes and body composition in Stizostedion lucioperca exposed to handling stress

Stizostedion lucioperca aquaculture/stoking, remains a restrained industry due to several factors such as the paucity of freshwater resources and studies on the physiological responses of this species under environmental changes. The fish were subjected to handling stress by holding them out of the water in a hand-held dip net for 30 sec and netting the fish from the rearing tanks and transferring them to a small confinement tank. Sufficient aeration was supplied to the confinement tank to revert additional stress from oxygen depletion. Then measured changes in plasma cortisol levels and the growth ability (body composition) in Stizostedion lucioperca subjected to handling stress. Blood samples were collected from the fish after exposure to the handling stress. Crude protein (Nx6.25) was determined according to the Kjeldahl method, moisture content was determined by oven drying at 105+/-2 degrees C to constant weight and ash by heating in a muffle furnace at 550 degrees C to constant weight. Total lipids were extracted according to the Bligh and Dyer method. The results indicated that, handling stress significantly increased the plasma levels of cortisol 59.04 ng mL(-1) versus 40.83 ng mL(-1) in control group. Also the decrease of the level of protein and lipid concentrations show a significant difference between treatment and control (p<0.05). As protein and lipid decreased, moisture increased from 78.19% in control to 80.40% in treatment groups. According to the results, there was no significant change in ash content in control and treatment groups which was about 9%. In other words, it could be emphasized that nutrition-related behavior of Stizostedion lucioperca resulting from the activation of the hypothalamic/inter-renal axis in response to stress despite of different reactions bear resemblance to that of other fishes. Present data indicate that cortisol appears to be adequate to assess stress in Stizostedion lucioperca.     

Expression of the herpes simplex virus type 2 glycoprotein D in baculovirus expression system and evaluation of its immunogenicity in guinea pigs

Background: Herpes simplex virus type 2 (HSV-2) is highly prevalent and major cause of genital herpes in humans. The life-long nature of infection and the increasing prevalence of genital herpes imply that vaccination is the best strategy for controlling the spread of infection and limiting HSV disease. HSV glycoprotein D (gD) is one of the most important viral immunogen which has an essential role in virus infectivity and induction of immune responses. Methods: HSV-2 DNA was extracted and used as template in polymerase chain reactions to amplify gD2 gene. The PCR product was confirmed by restriction enzyme analysis, cloned into a cloning vector and then sequenced. The Bac-to-Bac expression system was used to express HSV-2 gD in insect cells. The expressed protein was used as subunit vaccine to immunize guinea pigs after confirmation. Results: The expressed protein was confirmed with SDS-PAGE and Western-blot analysis. In Western-blot analysis, two major protein bands, with approximate molecular weights of 52-55 and 41-43 kDa corresponding to the glycosylated and non-glycosylated forms of gD2 protein, were observed, respectively. Immunization with the recombinant gD2 could elicit humoral responses in guinea pigs as measured by neutralization test and ELISA, and offered high protection against induced HSV-2 genital disease. Conclusion: The baculovirus expression of heterologous genes permits proper folding, post-translational modification and oligomerization in manners that are often identical to those that occur in mammalian cells. Expression of proteins under the control of the strong polyhedrin promoter, allowing high level protein production, can be used as subunit vaccine.     

Estimation of the organic carbon content by the pattern recognition method

Studying the status of agricultural soils is one of the most important concerns in the agricultural sector. The soil organic carbon (SOC) is one of the main parameters and it plays an important role in improving soil properties. Hence, knowing this parameter is important in soil science. This study applied the pattern recognition (PR) method in predicting the SOC. Also, the ability of this method was compared with different methods such as the Radial Basis Function Network (RBF), Multilayer Perceptron Neural Network (MLP), Multiple Linear Regression (MLR) and Support Vector Regression (SVR). To compare the results, four performance criteria, namely, root mean square errors (RMSE), the Nash–Sutcliffe efficiency (NS), Willmott’s Index of agreement (WI), mean absolute error (MAE) and Taylor diagrams were used. Results indicated that the PR model performed significantly better than the MLP, MLR, SVR, and RBF models for the estimation of the SOC.     

Effects of neonatal diarrhea and other conditions on subsequent productive and reproductive performance of heifer calves

Diarrhea is one of the most frequent diseases of neonatal calves in dairy herds. The aim of this study was to evaluate the effects of neonatal diarrhea and other conditions on subsequent first lactation milk production and reproductive performance of heifer calves up to the first calving. Seven hundred heifer calves (350 with and 350 without the history of diarrhea in first month of life) were monitored from birth until a year after calving. For each heifer, birth season, birth weight, ease of birth and occurrence of diseases from birth to the end of first lactation were recorded as independent variables. Interval from birth to first service, interval from birth to conception, interval from birth to first calving and 305-days milk yield in the first lactation were recorded as dependent variables. Effects of explanatory variables on productive and reproductive indices were evaluated by survival analysis and general linear model. Heifers with the history of diarrhea during the first month of their lives showed lower daily hazard of conception [Hazard ratio: 0.85 (95%CI: 0.73–0.99)] and calving [Hazard ratio: 0.84 (95%CI: 0.72–0.98)] than those of healthy heifers. Subsequent reproductive performance of heifer calves was also associated with birth season and ease of birth. Further, heifer calves born with birth weight of below 35 kg produced an average of 518 and 506 l less milk in their first lactation compared to calves with a birth weight 40–45 (p = 0.013) and greater than 45 kg (P = 0.033), respectively. These findings showed that occurrence of neonatal diarrhea and other neonatal parameters are associated with harmful effects on subsequent production and reproductive performance.     

Physiological characteristics and irrigation water productivity of quinoa (Chenopodium quinoa Willd.) in response to deficit irrigation imposed at different growing stages—A field study from Southern Iran

Iran has been faced to drought during last decades, and one way to overcome this phenomenon is to improve the water productivity by introducing new crops tolerant to water stresses such as quinoa. Two-year field experiment was performed to find out the response of quinoa (cv. Titicaca) to deficit irrigation imposed at different growing stages. Hence, the effect of full irrigation (100% irrigation water requirement) and deficit irrigation (50% full irrigation) on physiological parameters, yield, irrigation water productivity and root density of quinoa was investigated during 2016 and 2017 growing seasons. The result showed that there was a significant difference between all variables in two years. Higher average air temperature in 2017 (2.0°C) resulted in a reduction of seed yield and water productivity (55% and 40% of that obtained in 2016, respectively). Application of deficit irrigation during different growing stages reduced crop height, stomatal conductance and seed yield, while it increased the root length density in both years. In conclusion, flowering stage of quinoa was very sensitive to deficit irrigation, and irrigation at grain filling stage would not help to recover the seed yield. Furthermore, the seed yield was lower than that obtained in other studies performed in other countries using same quinoa cultivar, which could be due to higher amount of applied irrigation water and different phenology under different climatic conditions. A decision on cultivating this crop under semi-arid conditions has to be made considering limited water resources.     

Mechanical properties and in vitro degradation of PLGA suture manufactured via electrospinning

The current research discusses the efforts to achieve a Poly(lactide-co-glycolide)(PLGA) nanofiber yarn using two differently charged nozzles with potential application as surgery suture. First, electrospinning parameters such as solution concentration, applied voltage, feed rate were optimized to produce yarn with smooth nanofibers. In order to improve the properties of produced suture, heat setting setup was developed. Two heat setting techniques, including hot water and dry heat were applied, and the influence of the heat setting process on the mechanical properties of yarn was studied. The results showed that heat setting with boiling water was the best method. At first strength, E-modulus and extension of prepared suture were 36.6 MPa, 0.9 GPa and 68.8 % respectively. After improvement with heat setting, strength and E-modulus increased to 63.7 MPa, 2.7 GPa respectively and extension decreased to 29.7 %. Finally, in order to analyze knot performance, two types of surgical knot (square and surgeon) were used, and mechanical properties were investigated. The presence of knot lessens mechanical properties for each two type. Square knot showed better mechanical properties than surgeon’s knot. With square knot strength, E-modulus and extension were 62.1 MPa, 2.1 GPa, 28.6 %, respectively. In vitro study of nanofiber yarn degradation behavior showed that the mechanical properties were decreased. This could be due to greater surface area of nanofibers exposed to surrounding environment.     

Effects of Different Types of Composts on Soil Characteristics and Morphological Traits of Two Dry Rangeland Species

Today, environmental protection and safe crop production are very important. The management of soil elements by compost is considered as important for sustainable agriculture. The mode of action of the composts is very different between various plant species. To evaluate the effects of different composts on soil structural and chemical properties and on morphological traits of two dry rangeland species (atriplex; Atriplex lentiformis and mesquite; Prosopos juliflora), a study was conducted in Fars Province of Iran during the year 2010. The study was a factorial experiment based on a randomized complete block design with three replications. Treatments included compost types: solid (SC) and liquid compost or compost tea (LC), solid-liquid mixture (XSL) and control (Con; non used compost) as the first factor, and two pasture plant species as the second factor. The results showed that the compost application had significant and positive effects on morphological traits such as plant height, stem diameter, plant volume, crown length, width, and area, and caused 15, 51.18, 70.67, 34.18, 18.35, and 64.94% increase on these morphological traits, respectively. Although soil acidity was not significantly affected by compost and species, the effects of compost were significant on organic matter percentage, soil phosphorous, and potassium contents. Soil nitrogen percentage was affected by both species and compost. Compost application caused a decrease in the amount of sodium compared with the control. Overall, the results of this study suggested that within the compost types, liquid compost was an advisable biofertilizer in a similar climate. Furthermore, the LC and the XSL are recommended for improving the morphological traits and the soil characteristics, respectively.