Distribution and severity of damage by Cryphonectria parasitica in the chestnut stands in Guilan province,Iran

Chestnut blight caused by Cryphonectria parasitica has recently been reported from Guilan province, the only region with natural chestnut (Castanea sativa) stands in Iran. During the past few years, chestnut stands in Iran have been seriously threatened by the fungus, incidence of the disease is increasing and vast canopies are reduced to sprouts. As yet, there is no report on the disease distribution and severity in this region. Six sites from three main growing regions of chestnut in Guilan province were selected for investigation. We report occurrence and evaluation of the damage of the disease caused by C. parasitica. To evaluate the scale of damage, the investigated trees were classified into six categories based on the degree of crown damage, the number of canker wounds and the presence of the fungus. Index of health condition was calculated for all sites. During this study, a total of 250 isolates of Cryphonectria species were obtained, of which 232 isolates were C. parasitica and 18 were Cryphonectria radicalis. Castanea parasitica was observed in all regions. Index of health condition was scored from 0 to 6 with 0 being disease free and six being the most severe infection. Index results in the investigated sites varied between 0.69–5.45 and 0.93–5.55 for years 2006 and 2007, respectively. The highest damage was found in Doran (I_H = 5.55), which is located some 100 km away from Shahbalutmahalleh, the site with lowest damage (I_H = 0.93). This is the first extended report on aspects of chestnut blight in Iran.     

The relationship of plasma leptin concentration and puberty in Holstein bull calves (Bos taurus)

The objective of this experiment was to study the changes of plasma leptin concentration during puberty and its relationship with testosterone level and testis dimensions in Holstein bull calves. Six Iranian Holstein bull calves with approximately 6 months of age were used. Semen evaluation was conducted at 1‐month interval to determine the puberty state. To detect the plasma leptin and testosterone changes, blood samples were collected from the jugular vein during pre‐puberty (6–7 months of age), puberty (8–9 months of age) and post‐puberty (10–11 months of age). In addition, body weight (BW), body condition score (BCS) and testicular width and length were measured at 3‐week intervals. The effects of time (age) on total sperm number and percentage of progressive motility of sperm, plasma concentration of leptin and testosterone, amplitude and frequencies of testosterone, BW, BCS, testicular dimensions were significant. Sperm number and progressive motility during post‐puberty were higher than those during puberty and pre‐puberty. Plasma concentration of leptin during the pre‐puberty was higher than those during puberty and post‐puberty (p < 0.01). Mean plasma testosterone concentrations during puberty were higher than those during pre‐puberty (p < 0.05). BW, BCS and testicular dimensions consistently increased throughout the trial. Results indicated that in growing bull calves, plasma concentrations of leptin decreased during puberty, while circulating testosterone increased.     

The detection of a population of submillimeter-bright, strongly lensed galaxies

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.     

库尔勒香梨光合特性的初步研究

[目的]了解库尔勒香梨光合生理特性及其相关变化规律.[方法]利用Li- 6400光合作用测定系统测定库尔勒香梨两种树形的光合特征参数,通过试验测得光合色素含量以及比叶重,进行分析探讨.[结果]两种树形的光合色素含量存在差异,疏散分层形树的Chla含量极显著大于开心形,Chla+ Chlb值在25.88～38.96 mg/cm2,而两种树形之间的比叶重均值相差不大;开心形和疏散分层形的光补偿点(LCP)分别是28.75、33.22 μmol/(m2·s),在光强为1 090 μmol/( m2·s)时开心形树达到光饱和点,对应最大净光合速率值为18.61 μmol/(m2·s),低于疏散分层形的饱和光强1 150 μmol/( m2·s);开心形和疏散分层形的CO2浓度补偿点分别是63.55和57.04 μmol/mol,两种树形的羧化效率(CE)分别为0.039 5、0.036 6.在CO2浓度达到1 135 μmol/mol时,开心形的净光合速率达到最大值,为29.34 μmol/( m2·s),疏散分层形CO2饱和点(CSP)为1 165 μmol/mol.[结论]疏散分层形树对强光以及对CO2的利用率较高.     

Resistance against rhizomania disease via RNA silencing in sugar beet

Rhizomania is one of the most damaging and widely spread diseases in major sugar beet growing regions of the world. The causal agent, beet necrotic yellow vein virus (BNYVV), is transmitted via the fungus Polymyxa betae, which retains it in the field for years. In this study, an RNA silencing mechanism was employed to induce resistance against rhizomania using intron‐hairpin RNA (ihpRNA) constructs. These constructs were based on sequences of the BNYVV 5′‐untranslated region of RNA‐2 or the flanking sequence encoding P21 coat protein, with different lengths and orientations. Both transient and stable transformation methods produced effective resistance against rhizomania correlated with the transgene presence. Among the constructs, those generating ihpRNA structures with small intronic loops produced the highest frequencies of resistant events. The inheritance of transgenes and resistance was confirmed over generations in stably transformed plants.     

Effects of probiotic Pediococcus acidilactici on growth performance,survival rate,and stress resistance of Persian sturgeon (Acipenser persicus)

This study was conducted to examine the effect of Artemia urmiana nauplii enriched with Pediococcus acidilactici on growth performances, survival rate, and stress resistance of Persian sturgeon (Acipenser persicus). Artemia nauplii were enriched with P. acidilactici at concentration of 10¹⁰ CFU/ml for 3 h (T3), 6 h (T6), 9 h (T9), and one nonenriched nauplii treatment (control). Since nauplii enriched for 9 h had the most significant CFU/g, fish were fed with T9 for 11 days and compared with the control. To evaluate the effect of probiotic on fish resistance, Persian sturgeon larvae were subjected to osmotic shocks of 15, 25, or 35 ppt; four pH treatments, pH 5, pH 6, pH 8 or pH = 9; and air for 5, 10, 15, or 20 s on the 11th day. There were no significant differences in final weight, weight gain, CF, SGR, and FCR between T9 and control (P > 0.05). However, the survival rate of larvae fed nauplii enriched for 9 h increased significantly in comparison with the control group (P < 0.05). In addition, significant higher resistance to all stress challenges was observed in the T9 group.     

A reduced organic carbon component in martian basalts

The source and nature of carbon on Mars have been a subject of intense speculation. We report the results of confocal Raman imaging spectroscopy on 11 martian meteorites, spanning about 4.2 billion years of martian history. Ten of the meteorites contain abiotic macromolecular carbon (MMC) phases detected in association with small oxide grains included within high-temperature minerals. Polycyclic aromatic hydrocarbons were detected along with MMC phases in Dar al Gani 476. The association of organic carbon within magmatic minerals indicates that martian magmas favored precipitation of reduced carbon species during crystallization. The ubiquitous distribution of abiotic organic carbon in martian igneous rocks is important for understanding the martian carbon cycle and has implications for future missions to detect possible past martian life.     

Maximizing seed germination in two Acacia species

Revegetation of disturbed land, particularly in arid environment, is often hindered by low seedling establishment. Information on seed biology and germination cues of valuable species is lacking. We investigated seed germination of two Acacia species (Acacia tortilis (Forsk.) Hayne and Acacia oerfota (Forssk) schweinf), required for nitrogen fixation and rehabilitation of arid and semi-arid areas.(four pre-germination seed treatments were applied in order to find the best treatment in germinating acacia species. The medium was L2 and three replicates were used. Seeds pre-treated with sand paper and also with H2SO4 and then H2O2 had the highest germination percentage in both species. The lowest germination percentage resulted from soaking seeds in water for 48 h followed by soaking in H2SO4 for A. oerfota and from soaking in water for 24 h for A. tortilis. Because the use of sand paper is difficult and time consuming, we recommend pre-treatment of A. tortilis and A. oerfota seeds with H2SO4 and H2O2 before planting. Our study results are significant for conservation agencies with an interest in optimizing germination in arid zones for rehabilitation and reforestation.     

Influence of dietary acetic acid,protexin (probiotic), and their combination on growth performance,intestinal microbiota,digestive enzymes,immunological parameters,and fatty acids composition in Siberian sturgeon (Acipenser baerii,Brandt, 1869)

Aquaculture International - This study was performed to investigate the effects of dietary acetic acid, probiotic protexin, and their combination on growth performance, intestinal microbiota,...