Comparison of selection methods among and within full-sibling progenies in Urochloa humidicola

Hybridization in the Urochloa humidicola breeding programme allowed to explore the genetic variability of the apomictic sources and, thus, to obtain new sexual and apomictic parents with compatible ploidy and/or superior progenies. However, given the high variability arising from crosses, there is a need to adopt efficient selection strategies among and within progenies. The aim of this study was to compare the selection methods among U. humidicola progenies with (t-BLUP) and without (BLUP) the weighting based on prediction error and subsequent selection within progenies by individual simulated (BLUP_IS) or optimal individual BLUP. We evaluated seventy-one U. humidicola full-sib progenies from biparental crosses between nine sexual and ten apomictic parents. The experiment was set up in an incomplete block design with 64 blocks of 15 plots each, consisting of individual plants. Seven consecutive cuts were made and the traits total dry-matter, leaf dry-matter and regrowth scores were measured. Genetic variance was expressive for all traits. The selection procedure among progenies of U. humidicula based on t-BLUP proved to be more advantageous regarding the use of BLUP not weighted by the prediction error, resulting in higher selection gains, taking as reference the optimal procedure of the individual BLUP. Furthermore, the use of BLUP_IS allowed an optimized selection of hybrids, allowing the breeder to explore with variable selection intensity the genetic variability within the selected full-sib progenies based on relative genetic merit.     

Nephrotoxicity and oxidative stress of single large dose or two divided doses of gentamicin in rats

Gentamicin (GS) is a potent antimicrobial exhibiting concentration dependent bacterial killing. A high dose ofgentamicin (10 mg kg(-1)) is required to reach sufficient concentrations in specific fluids as cerebrospinal fluid and to be effective on antibiotics resistant bacteria as well as treatment of acute and dangerous illness. Using a rat model, the renal toxicity and oxidative stress of administering gentamicin (10 mg kg(-1) daily for 7 days) either in a single dose or divided into 2 doses was investigated. The safety of dose regimens was assessed through oxidant-antioxidant parameters as well as renal function tests. Typical renal damage and high oxidative stress were evident in the control group receiving 100 mg kg(-1) gentamicin daily for 7 days. This was verified by high serum urea, uric acid, creatinine as well as increase in the levels of oxidative stress biomarkers as malondialdehyde, NO, total antioxidant capacity and decrease in reduced glutathione level. At any of the used regimen, 10 mg kg(-1) gentamicin did not provide high compromise for renal functions nor significantly increased the oxidative stress and tissue damage. Based on microscopic lesions scores and biochemical analysis, there were no significant differences between single or two divided dosages of gentamicin at dose rate of 10 mg kg(-1) day(-1). Further studies are required for applications in other animals of human subjects.     

Pseudomonas putida improved soil enzyme activity and growth of kasumbha under low input of mineral fertilizers

Effective management of the nutrients and enzyme activity in the soil is necessary for maximum crop growth and productivity. However, the excessive use of chemical fertilizers (CFs) not only adversely affects the soil nutrient status and soil physicochemical properties but also aids pollution to the ecosystem. The objective of present study was to investigate the effect of single as well as combined applications of phosphate-solubilizing bacteria and agrochemicals on important soil enzyme activities and their impact on the growth of kasumbha (safflower). Pseudomonas putida (P. putida;10⁶ cells/mL) was applied as seed inoculation prior to sowing, and CFs were applied as full, half, and quarter doses during sowing to modulate the growth of kasumbha host plants. P. putida in combination with half dose of CFs (PH) increased the soil urease and phosphatase activities, while P. putida combined with quarter dose of CFs (PQ) augmented the soil invertase activities. Moreover, the PQ treatment exhibited the maximum colony-forming units of P. putida. Leaf chlorophyll, carotenoids, protein contents, and root lengths were increased by PH treatment. Whereas, shoot length and leaf area were improved by PH and PQ treatments, respectively. Leaf protease activity was enhanced by P. putida in combination with full dose of CFs and PQ treatments, while leaf phosphate contents were significantly improved by PQ treatment. It can be concluded that P. putida in combination with half as well as quarter doses of CFs is a promising approach for the improvement of soil enzyme activities and growth of kasumbha and replacing 50% of the use of CFs.     

Antiparasitic efficacy of dietary administration of trichlorfon (Masoten®) in the control of Neoechinorhynchus buttnerae (Neochinorhynchidae) in Colossoma macropomum (Serrasalmidae)

Aquaculture International - This study investigated the efficacy of trichlorfon against Neoechinorhynchus buttnerae, as well as its palatability, residue analysis, and the blood parameters of...     

澳大利亚和新西兰硫肥研究和应用进展

含硫肥料农用效果与其水溶性、成粒状态以及颗粒大小密切相关. 对澳大利亚东部及新西兰现有含硫肥料的调查表明,当前所用的肥料品种甚多.大田作物和牧草现用的肥料中, 硫酸盐态(SO4)和元素态硫(S0)的比例范围很宽.澳大利亚现已开展了许多硫酸盐态硫源和元素硫态硫源肥料的比较试验.在粗质地土壤中,由于硫酸盐的淋失,常常降低植物对这类硫肥利用的效果.元素态硫颗粒的细度是其氧化速率的决定因素.这个问题可以很容易地在肥料中添加元素硫时通过配方巧妙地加以解决.这种含元素硫的肥料在澳大利亚有两种,一种是将元素硫与肥料充分混合后制成颗粒,另一种是将元素硫作为包衣,裹在肥料颗粒表面.土壤硫的测定现在还未被农民广泛使用.困难之一是土壤有机硫转化成硫酸盐的量变动很大.在一个35SO4示踪盆栽试验中根据脂态硫酸盐的有机库、吸附态和可溶态硫库、碳键硫库,以及植物中硫的转化情况来观察土壤中硫酸盐移出的快慢.新英格兰大学的研究者们,采用了各种土壤进行了一系列的这种试验.在大量的温室和田间试验研究中,用0.25 mol/L KCl溶液在40℃下浸提的土壤硫比用其他浸提剂提取的硫更能预示或表明土壤硫有效性状况,因为0.25 mol/L KCl,40℃提取了相当于作物所吸收的那部分吸附态硫、脂硫和土壤溶液中硫酸盐.雨水中的硫能够提供植物一定数量的硫.澳大利亚降雨中含硫情况的调研发现,不同地区降雨中硫的含量及季节性分配都有明显差异.在塔斯马尼亚 (Tasmania) 西海岸的Smithton 和塔斯马尼亚东北地区的Rushy Lagoon 两个地区降雨中的硫含量最高,前者每年每公顷降水含硫20.3 kg,后者11.7 kg.相反,在塔斯马尼亚中部的Jericho 降雨中含硫量最少,每年每公顷降雨中的硫仅有0.41 kg.在新西兰的类似试验也表明了降雨中含硫量的差异.因此,在施肥时,就必须对降雨中硫量加以考虑.在临近大海和工业中心,雨水中通常都含有相当量的硫,在需要施硫肥时,必须扣除雨水中的硫量.     

Comparing N-labelling techniques for enriching above- and below-ground components of the plant-soil system

Comparisons were made of three different ¹⁵N-feeding techniques, leaf, petiole and stem feeding, to identify the most efficient technique for labelling above-and below-ground plant biomass under controlled environment conditions. ¹⁵N-urea (0.5%, 10 atom % excess ¹⁵N) was applied to chickpea (Cicer aritenium var. ICCV 5003) plants twice during early growth. Leaf feeding was found to be the most efficient in terms of ¹⁵N-solution uptake (5.9 ml 48 h⁻¹) and ¹⁵N-enrichment at harvest, with 0.95, 0.41, 0.79, 0.67 and 0.22 atom % excess ¹⁵N in the leaves, stems, grain, grain straw and clean root fractions, respectively. Solution uptake was low in the second stem feeding event due to blockage of the drilled hole, resulting in low ¹⁵N-enrichment of leaves (0.29 atom % excess ¹⁵N). Although petiole feeding resulted in more even relative enrichments among plant parts our results highlight the usefulness of leaf ¹⁵N-feeding to estimate below-ground plant N and to trace the long-term fate of plant-derived N within the soil.     

Comparative analysis of <Emphasis Type="Italic">Argonaute</Emphasis> gene sequences in bananas (<Emphasis Type="Italic">Musa</Emphasis> sp.) shows conserved species-specific Ago-7 PIWI domains

The Argonaute proteins are key components in the effector complex of RNA silencing pathways which interact with small RNAs to mediate sequence specific silencing of nucleic acid targets. In plants, these proteins are involved in a diversity of biological roles such as antiviral defence, heterochromatin regulation and in the regulation of growth and development. This report describes the study of Argonaute gene sequences in bananas which are an important food staple for many developing nations. This study successfully isolated AGO7-specific PIWI domain genomic sequences from 12 diploid Musa species of three Musa sections and also from Ensete. The Musa AGO7-specific PIWI domain sequences showed the highest similarity to rice AGO7/SHOOTLESS4 with an average amino acid identity of 78%. Phylogenetic analysis of the Musa sequences revealed phylogenetic grouping that agrees fairly well with the present knowledge of the taxonomic classification of Musa species. In addition, this study estimated that there are at least 15 Argonaute genes or loci containing PIWI domain sequences in the genome of Musa acuminata ssp. malaccensis.     

Polycyclic Aromatic Hydrocarbons (PAHs) in the Aerosol of Higashi Hiroshima, Japan: Pollution Scenario and Source Identification

Polycyclic aromatic hydrocarbons (PAHs) are considered to be atmospheric pollutants and well-known human carcinogens. This study analyzes the pollution scenarios of PAHs in the aerosol of Higashi Hiroshima, Japan. We examined the characteristics, the influences of meteorological conditions, the distribution and seasonal variation of PAHs in aerosol samples collected from June 2000 to May 2001. The concentration of PAHs in the aerosol of Higashi Hiroshima was ranging from 11.8 to 157.5 μg/g with a mean concentration of 63.4 μg/g. Results showed that there is positive correlation between aerosol PAH concentrations and ambient temperature but a relatively little correlation with solar radiation. Seasonal variation was observed with a higher concentration during winter and lower concentration during summer. Apart from that, principal component analysis and molecular diagnostic ratios were also used to characterize and identify possible PAHs emission sources. Results obtained strongly suggested that vehicular emissions appeared to be the major source of aerosol PAHs in this study although other sources do have some degree of influence.