Assessing and monitoring the soil quality of forested and agricultural areas using soil-quality indices and digital soil-mapping in a semi-arid environment

In recent decades, the conversion of forest to agricultural land has been a major worldwide concern and a cause of environmental and soil-quality degradation. In this study, soil-quality indices (SQIs) were applied using several soil properties to determine the effects of land use on soil quality in a 206.50 km² area in Kurdistan Province, Iran. The Weighted Additive Soil Quality Index (SQI_w) was calculated using two scoring methods and two soil indicator selection approaches. Nine soil-quality indicators/variables were measured for 124 soil samples (0–30 cm depth). Calculated SQIs were digitally mapped with a random forest (RF) model using auxiliary data. The RF model was the best predictor of the SQI computed using the total dataset (TDS) and linear score function (SQI_w-TDS-linear). Soil quality was better estimated using non-linear scoring (r² = 0.82) than with linear scoring (r² = 0.73). The mean values of all SQIs were significantly greater in forestland than cropland. It is clear that soil quality is considerably reduced by deforestation, and that best management practices that maintain soil quality and reduce erosion must be developed for the soils of this region if they are to remain productive.     

Organic and urea nitrogen fertilizer effects on rapeseed and wild mustard competition

The competitive effects of wild mustard on rapeseed with organic amendments and urea alone or combined were studied for 2 years. Treatments consisted of three Sinapis arvensis densities and fertilizer treatments of composted cattle manure, composted municipal waste, urea nitrogen, a combination CCM+urea, a combination of CMW+urea, and a control. Weed growth was stronger in urea fertilizer and with combined organic amendments than in organic amendments alone. However, application of organic amendments could increase weed competitive ability. In the first year, urea fertilizer alone and combined with organic amendments led to the greatest rapeseed yield, but in the following year, organic amendments alone were able to increase rapeseed yield approximately equal to urea fertilizer and combined with organic amendments. Application of organic amendments alone or combined with N fertilizer could be an efficient method to increase soil productivity.     

Ultra-structure of intracellular lipid vesicles of porcine GV-oocytes after in vitro fertilization and parthenogenetic activation

The aim of our investigation was to compare the ultrastructure of lipid droplets in porcine pronuclear oocytes obtained after in vitro fertilization (IVF) or parthenogenetic activation (PGA) of Metaphase II (MII) oocytes. The ultrastructure of lipids in the IVF or PGA pronuclear oocytes after vitrification was also studied. There are two kinds of lipid droplets in porcine GV oocytes: 'dark' and homogenous vesicles next to 'grey' vesicles with electron-lucent streaks. After IVF or PGA and following 16-h culture, only the presence of 'grey' vesicles was detected in IVF and PGA oocytes. Ultra-structure of lipid vesicles of PGA and IVF oocytes was similar. The PGA oocytes can be as model of the two pronuclear stage IVF oocytes.     

Effect of feed restriction early in life on humoral and cellular immunity of two commercial broiler strains under heat stress conditions

1. An experiment was carried out to evaluate the effect of early feed restriction (FR) on immunocompetence of Ross and Arian chickens with separated sexes under heat stress (HS) conditions. 2. Chickens consumed feed ad libitum (AL) or were restricted on alternate days from 11 to 20 d of age. From 35 to 41 d of age, the HS groups were exposed to a high ambient temperature of 39 +/- 1 degreesC for 7 h each day, while the thermoneutral groups (TN) were at 33 degrees C. 3. At 21 and 42d of age, the percentage of CD4+ (helper T cells) and CD8+ (cytotoxic T cells) were determined by flow cytometry. Antibody response to sheep red blood cells (SRBC) and heterophil/lymphocyte (H/L) ratio were determined on d 21 and 42. 4. On d 21, FR elevated the CD4+, antibody titre and H/L ratio, but it decreased the CD8+ T cells. On d 42, HS decreased CD4+, CD8+, and antibody titre, but it increased H/L ratio. Under TN conditions, FR chickens had higher CD4+ than AL chickens. On d 42, FR/HS chickens had higher CD4+ and antibody titre, but they had lower CD8+ and H/L ratio than AL/HS chickens. 5. On d 42, the TN-Ross strain had lower CD4+, but they had higher CD8+ and antibody titres than the TN-Arian strain. On d 42, the HS-Arian strain had higher antibody titres and a lower H/L ratio than the HS-Ross strain. 6. Male chickens had higher CD4+, CD8+, antibody titres and H/L ratios 25 in all treatment groups. 7. In conclusion, FR early in life reduced some of the negative effects of the heat stress on the immune system of broiler chickens when exposed to high environmental temperatures later in life.     

Distribution of enterococcal species and detection of vancomycin resistance genes by multiplex PCR in Tehran sewage

BACKGROUND: Enterococci are important because of their role as the leading cause of nosocomial infections which have a significant role in the dissemination and persistence of antimicrobial resistance genes. METHODS: In this study, we determined the distribution of enterococcal species in the sewage treatment plants in Iran. Furthermore, we improved a rapid and specific PCR method using primers (sodA and ddl genes) for identification of enterococci spp. RESULTS AND CONCLUSION: A total number of 712 enterococci spp. were isolated and the results showed that 56%, 24%, 12%, 4%, 2%, 1% and 1% isolates were E. faecium, E. hirae, E. faecalis, E. gallinarum, E. casseliflavus, E. mundtii and other enterococcal spp., respectively. The use of species-specific PCR was in agreement with the biochemical tests. Furthermore, multiplex PCR was developed to study the presence of vancomycin resistant genes in E. faecium or E. faecalis. The multiplex PCR appeared to be a useful, rapid and specific method for detecting and discriminating genotypes for vancomycin-resistant Enterococcus.