甘蔗与抗旱性相关差异蛋白质组分析

采用桶栽方式,对抗旱性强的F172和抗旱性弱的YL6甘蔗品种在苗期进行重度干旱胁迫处理后,应用蛋白质双向电泳技术进行差异蛋白质分析,分别找出差异显著的28和20个差异蛋白点,其中部分呈现上调表达,部分呈现下调表达,还有部分新增的蛋白点,因品种抗性不同而表现各异,F172叶片中的差异蛋白主要表现为上调表达,而YL6中大多表现为下调表达。在重度干旱胁迫下,抗旱性不同的甘蔗品种蛋白质丰度变化有显著差异。采用MALDI-TOF-TOF/MS鉴定所获得的差异蛋白,从YL6、F172中分别鉴定出18、14个蛋白的氨基酸序列,对所鉴定的蛋白质根据功能分为8类。YL6中参与自由基清除的2个,参与光合作用的6个,参与细胞生长和分裂的1个,参与基础代谢的6个,参与防卫反应的2个,未知功能蛋白1个。F172中参与自由基清除的1个,参与光合作用的2个,参与细胞生长和分裂的2个,参与基础代谢的4个,参与信号转导的2个,参与蛋白加工的1个,未知功能蛋白2个,其中22 k D干旱诱导蛋白的丰度明显提高,而在YL6中则检测不到此蛋白。这说明在干旱胁迫下抗旱性不同的甘蔗品种在蛋白质组成上有很大差异,推测这是不同甘蔗品种间抗旱性差异的重要分子基础。     

Ultrastructural Study of the Early Development of the Sheep Embryo

An ultrastructural study of the different stages of pre-implantation in sheep was carried out, analysing the changes brought about mainly in the morula and blastocyst stages. The analysis of the embryos obtained showed a series of common characteristics in all stages, most noticeable being the presence of a high number of vesicles distributed in a uniform way in the cytoplasm, and also the presence of numerous electron-dense mitochondria in many varied forms. The most important ultrastructural modifications took place at the 16-cell stage and affected, principally, the nucleus, which presented numerous condensations of chromatin distributed along the nucleoplasm. The nucleoli adopted a reticular morphology, abandoning the compact aspects presented in the previous stage. These changes might be involved in the synthesis of embryonic RNA, and, accordingly, in the activation of the genome of this species. These data indicate that this stage is critical to the embryonic development and might be related to the blockage produced in the development of cultivated sheep embryos at the point of transition from 8 to 16 cells. Nevertheless, it should be pointed out that the first signs of modifications in the aspect of the nucleus are observed at the four-cell stage, being characterized by the appearance of vacuolated areas in the nucleolus, indicating the first signs of embryonic nucleic activity, which would anticipate the main change in the control of the protein synthesis.     

Flavobacterium columnare genomovar influences mortality in channel catfish (Ictalurus punctatus)

Flavobacterium columnare, causal agent of columnaris disease, is pathogenic to many species of freshwater fish throughout the world. The United States channel catfish (Ictalurus punctatus) aquaculture industry is severely impacted by columnaris disease. The majority of the F. columnare isolates recovered from diseased channel catfish belonged to either genomovars I or II. The objective of the present study was to determine if differences existed in the ability of these genomovars to induce mortality in channel catfish. Single strand conformation polymorphism analysis (SSCP) was used to ascribe the isolates used in this study to the appropriate genomovar. Immersion challenge experiments (15min immersion exposure to approximately 5x10(5) to 1x10(6) CFU/mL) were carried out to assess virulence of genomovar I and II isolates to channel catfish. The results demonstrated that genomovar II (n=4) isolates were significantly (P<0.05) more virulent to channel catfish fry (92-100% mortality) than genomovar I (n=3) isolates (0-46% mortality). In vivo adhesion of the genetically characterized F. columnare also correlated (r2=0.73) to increased mortality in the challenged fry. In fingerling channel catfish, significantly higher mortality (P<0.05) resulted with genomovar II isolates ALM-05-182 and ALG-00-530 as compared to all the genomovar I isolates (n=3). Mortality of genomovar II isolate BGFS-27 with similar to genomovar II isolate (ALG-00-530) and two genomovar I isolates (ALM-05-53 and 140). The results suggest that although both genomovars are present in the aquatic environment, genomovar II appears to be more pathogenic for channel catfish.     

Implications of Rock Fragments for Soil Quality Evaluation: Assessing Changes in a Gravelly Irrigated Soil Following No Till Adoption

Stony soils are increasingly being converted to intensive agricultural use, including irrigation. Conservation tillage can be adopted in these soils for soil protection and quality enhancement, but its assessment can be troublesome. Crop yields and the implications of rock fragments for soil quality indicators and for calculating C and N stocks were monitored under conventional and no-tillage in an experimental field recently converted to irrigation, on a soil with 40% rock fragments. Gains of up to 10 Mg C ha^?1 were observed in the tilled layer (0–30 cm) only with two years of irrigation, with no differences between treatments, although the vertical distribution of carbon (C) and nitrogen (N) was affected by the correction of the rock fragment content. The labile organic fraction stood as a sensitive indicator to management changes, even after rock fragment correction. Different methodologies used for rock fragment correction led to overestimations of 20% of organic C stocks.     

Scanning Electron Microscopy of “Saddleback” Lesions Associated with Experimental Infections of Flavobacterium columnare in Channel Catfish,Ictalurus punctatus (Siluriformes: Ictaluridae), and Zebrafish,Danio rerio (Cypriniformes: Cyprinidae)

Laboratory‐reared, specific pathogen‐free fingerling channel catfish, Ictalurus punctatus, and adult zebrafish, Danio rerio, were each separately exposed by immersion challenge to the etiological agent of “columnaris disease,”Flavobacterium columnare (Japanese Collection of Microorganisms 21327 strain). At 24‐h post‐immersion, fish exhibiting a “saddleback” lesion were fixed whole in 10% neutral buffered formalin. Skin samples approximately 5 mm² were excised from both the margin and center of each saddleback lesion as well as from corresponding sites in control, non‐challenged, fish before being prepared routinely for scanning electron microscopy (SEM). Skin samples from control channel catfish and zebrafish had uniform, contiguous epidermal cells with continuous or closely apposed cell margins and well‐defined microridges. Channel catfish skin lesion samples had margins typified by epidermal sloughing and lesion centers that exhibited a multitude of rod‐shaped bacterial cells, approximately 3–10 µm long × 0.3–0.5 µm wide, intermingled with cellular debris across a surface characterized by denuded, strongly ridged, or folded dermal connective tissue. Zebrafish skin lesion samples had a multitude of rod‐shaped bacterial cells and exhibited comparable ultrastructural changes but some lacked scales. These findings are the first published SEM observations of columnaris disease and saddleback lesions in channel catfish and zebrafish and thereby advance our understanding of the ultrastructural characteristics of acute‐stage saddleback lesions and columnaris disease pathogenesis.     

Fumonisins: probable role as effectors in the complex interaction of susceptible and resistant maize hybrids and Fusarium verticillioides

Fusarium verticillioides is best known for its worldwide occurrence on maize resulting in highly variable disease symptoms, ranging from asymptomatic to severe rotting and wilting and fumonisin production. The aim of this study was to investigate the influence of hybrid genotypes in the early stages of F. verticillioides infection, and the role of fumonisins as effectors in the outcome of this complex interaction. Disease symptoms, growth parameters, root morphology, and fungal colonization were evaluated at 7, 14, and 21 days after planting in seedlings from maize seeds of resistant (RH) and susceptible (SH) hybrids inoculated with F. verticillioides or watered with solutions of fumonisins. F. verticillioides induced growth enhancement or retardation depending on the plant genetic background and the fungal colonization rate, while fumonisins caused severe reduction in biomass and fitness. Seedlings watered with high fumonisin concentrations displayed lesions similar to those seen in F. verticillioides maize seedling disease, and also elicited inhibitory effects on root growth and morphology and on functional properties. In summary, these data strongly suggest a dual role for fumonisins in the F. verticillioides-maize interaction, acting as pathogenic factors at high concentrations, or triggering the plant detoxification mechanisms at low levels.     

Is the variability in my crop due to genetic or environmental factors? Using heritability to solve this question

Journal of Crop Science and Biotechnology - Usually is common to see great differences among plants in our crops, this can allow us to think about selection of some plants with the best traits in...     

Rapid and sensitive detection of African horse sickness virus by real-time PCR

A highly sensitive and specific TaqMan-MGB real-time RT-PCR assay has been developed and standardised for the detection of African horse sickness virus (AHSV). Primers and MGB probe specific for AHSV were selected within a highly conserved region of genome segment 7. The robustness and general application of the diagnostic method were verified by the detection of 12 AHSV isolates from all of the nine serotypes. The analytical sensitivity ranged from 0.001 to 0.15 TCID₅₀ per reaction, depending on the viral serotype. Real-time PCR performance was preliminarily assessed by analysing a panel of field equine samples. The same primer pair was used to standardise a conventional RT-PCR as an affordable, useful and simple alternative method in laboratories without access to real-time PCR instruments. The two techniques present novel tools to improve the molecular diagnosis of African horse sickness (AHS).     

Factors Controlling the Spatial Variability of Copper in Topsoils of the Northeastern Region of the Iberian Peninsula, Spain

Aerosol samples were collected at Catania (Italy), from 16 March to 13 June 2005. The sampling was performed using a low pressure five-stage Berner cascade impactor. The samples were analysed for total aerosol mass, Water Soluble Organic Carbon (WSOC), Total Carbon (TC) and main inorganic ionic species. The Water-Insoluble Carbon (WINC) was derived by the difference: TC-WSOC. The samples share some common features: ammonium sulphate and carbon-containing species (both soluble and insoluble) are the largest contributors of fine particle mass, while coarse particles essentially consist of sea-salt, sodium nitrate and unaccounted PM (probably crustal material). The WINC/WSOC ratio decreases from the smallest size range to the large accumulation mode range (0.42–1.2 μm), while the ${\text{nssSO}}^{ = }_{4} $ and $ {\text{NH}}^{ + }_{4} $ contribution rises. The water-insoluble carbonaceous matter is the dominant component in the smallest particles (0.05–0.14 μm). We identified four different aerosol types, corresponding to different sources, contributing to the total particles load of the investigated urban environment: vehicular traffic, producing primary carbonaceous insoluble particles, secondary aerosols, dominating the composition of accumulation mode particles, and marine particles and mineral dust (both important components of the coarse aerosol fraction).