丁布的生物活性研究进展

丁布是广泛存在于小麦、玉米等禾本科作物中的异羟肟酸类次生化学物质, 研究表明其具有广谱活性。本文从丁布的抗虫活性、抗菌活性、化感作用、土壤微生物活性、生态毒性及作用机理等方面进行了概述, 并对今后的研究进行了展望。     

Preliminary study on homing,site fidelity,and diel movement of black rockfish <Emphasis Type="Italic">Sebastes inermis</Emphasis> measured by acoustic telemetry

Several species of fish exhibit strong homing ability and distinct site fidelity to their original habitats and spawning sites. We have studied the homing ability, site fidelity, and diel movement patterns of three nocturnal black rockfish Sebastes inermis. The patterns were studied by radio-linked acoustic positioning system (VRAP) and fixed monitoring receivers (VR2) in Maizuru Bay, Japan from June to July 2004. All tagged fish were displaced by 80–120 m, but they returned to their respective captured sites at dusk, regardless of the time of release. The fish tagged with a depth sensor transmitter displayed active vertical movement just after the release, and subsequently swam near the bottom depth around the captured site. After homing, they displayed small home ranges [average 815 ± 265 m² (SD)] around a single rocky area with one or two core areas (average 64 ± 30 m²). One core area was utilized during the daylight and dark periods, whereas the other was used primarily during the dark period. The depth-tagged fish primarily used the depth of the rock crevice during the daylight, and it spent its dark period between the surface and the deeper bottom depth.     

A serologic investigation of epizootic hemorrhagic disease virus (EHDV) in cattle and gazella subgutturosa subgutturosa in Turkey

Epizootic hemorrhagic disease virus (EHDV) is a vector-borne disease of ruminants disseminated in the tropic and subtropic zone of the world. Gazella subgutturosa subgutturosa (goitered gazelle) is native species of Anatolia. Due to risk of extinction, captured gazelles have been taken under protection in a restricted area at Ceylanpinar state farm. In this study, the presence of EHDV was investigated serologically in 82 goitered gazelle and 399 cattle. Seropositivity rates in goitered gazelle and cattle were detected as 2.43% and 3.50%, respectively.     

不同行数植物篱对红枫湖坡耕地养分的拦截效应

为选出控制红枫湖坡耕地水土流失效果较好的植物篱带宽,对比了由香根草和灰毛豆混合建设(1∶1行间混交,>2行为行间交互混交)的不同行数的植物篱(每个处理小区种植3带植物篱,分别设每带2行,每带4行,每带6行,自上而下每带分别2、4、6行4个植物篱处理及对照共5个处理)对地表径流量、泥沙量及地表径流中水溶解态全氮、全磷、全钾、铵态氮和泥沙中的固体态的全磷、全钾的影响。结果表明:各植物篱处理的各项指标都小于对照处理;方差分析结果及F测验证明,处理间存在显著差异(P<0.05)。多重比较结果表明:1)除每带2行植物篱外,其他植物篱处理都相对于对照对养分元素具有显著的拦截作用。2)每带4行处理和自上而下各带分别2、4、6行植物篱处理与每带2行处理无显著差异;每带6行处理显著小于每带2行植物篱处理。3)除泥沙所含的磷、钾元素外,每带6行与自上而下分别2、4、6行植物篱无显著差异,每带6行的各个指标都与每带4行无显著差异。综合试验结果和实际应用要求得出,每带4行是本试验所涉及的植物篱行数中的最佳行数,其次自上而下每带分别2、4、6行的种植方式也较好。     

Genetic variability of faba bean genotypes for chocolate spot (<Emphasis Type="Italic">Botrytis fabae</Emphasis>) resistance and yield

Faba bean (Vicia faba L.) has high utility as a food and soil fertility improving crop. One of the major fungal pathogens of faba bean is Botrytis fabae, the causative agent of chocolate spot. The disease affects significantly the leaf, stem, pod and seed of faba bean compromise its productivity in the smallholder farming sector. Nonetheless, there are limited resistant/tolerant faba bean varieties available and disease control technology options. Therefore, it was prudent to evaluate faba bean landraces for chocolate spot resistance. Fifty landraces together with ten improved varieties were evaluated both in the field and in the greenhouse under natural and artificial inoculation with previously selected aggressive Botrytis fabae isolate (Iso-016) from West Gojjam, in Ethiopia. There were highly significant differences (p?<?0.001) among the landraces for reaction to the disease and agronomic traits. Significant positive correlation was recorded between reaction of genotypes in the field and greenhouse disease data. The overall mean disease epidemics varied from 92.5 to 697.5 for the area under disease progress curve (AUDPC). The highest level of resistance was found in the ICARDA lines, ILB-4726, ILB-938 and BPL-710. Of all 18 landrace collections displayed significantly lower disease reaction than the susceptible check. However the resistance was moderate. The selected eighteen landraces will be recommended for use in breeding for chocolate resistance. Overall, resistance was highly heritable, suggesting that phenotypic selection can be exploited to improve chocolate spot resistance in faba bean varieties.     

Effect of starvation on biochemical composition and gametogenesis in the Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis>

The effects of starvation on biochemical composition and gametogenesis were investigated in the Pacific oyster Crassostrea gigas. Histological analysis, combined with oocyte examination and measurements of protein, glycogen and lipid levels and RNA/DNA ratio from gonad, adductor muscle and mantle tissue of each sex were performed. In the starved groups, C. gigas showed gonad development, but the progress was delayed during the experiment. Glycogen was the first substrate used by C. gigas for dealing with lack of food. While glycogen was rapidly consumed, protein and lipid contents decreased gradually. A decrease in the RNA/DNA ratio in the starved groups in all the body components was found during starvation, illustrating that RNA/DNA ratio was a valid indicator of nutritional condition in C. gigas. A significant increase in water and ash contents and a corresponding decrease in condition index were observed in the starved groups, showing that the water and ash content and condition index were related to the usage of glycogen, lipid and protein reserves in body composition. During starvation, energy reserves were mobilized for survival and gonad development, but spawning was arrested. The information obtained in this study is useful for broodstock management in the Pacific oyster industry.     

Dietary docosahexaenoic acid decreased lipid accumulation via inducing adipocytes apoptosis of grass carp, <Emphasis Type="Italic">Ctenopharygodon idella</Emphasis>

The purpose of this study was to explore the mechanism of by which docosahexaenoic acid (DHA) inhibit the accumulation of adipose tissue lipid in grass carp (Ctenopharyngodon idella). We therefore designed two semi-purified diets, namely DHA-free (control) and DHA-supplemented, and fed them to grass carp (22.19 ± 1.76 g) for 3 and 6 weeks. DHA supplementation led to a significantly lower intraperitoneal fat index (IPFI) than that in the control group by reducing the number of adipocytes but significantly higher adipocyte size (P < 0.05). In the intraperitoneal adipose tissue, the DHA-fed group showed significantly higher peroxisome proliferator-activated receptor (PPAR)γ, CCAAT enhancer-binding protein (C/EBP)α, and sterol regulatory element-binding protein (SREBP)1c mRNA expression levels at both 3 and 6 weeks (P < 0.05). However, the ratio of the expression levels of B cell leukemia 2 (Bcl-2) and Bcl-2-associated X protein (Bax) was significantly lower in the DHA-fed group than in the control group (P < 0.05), and the protein expression levels of the apoptosis-related proteins caspase 3, caspase 8, and caspase 9 were also significantly higher (P < 0.05). Overall, although DHA promotes lipid synthesis, it is more likely that DHA could suppress the lipid accumulation in adipocytes of grass carp by inducing adipocyte apoptosis.     

High immune diversity in farmed Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.)

As with any other intensively farmed animal species, the Atlantic salmon has been selectively bred and cross-bred to maximize desirable traits. Selection tends to diminish genetic diversity in target populations, which among other negative effects is hypothesized to decrease their capacity to confront a broad variety of pathogens. We have analyzed mitochondrial (mtDNA) as well as major histocompatibility complex (MHC) DNA sequences from individuals collected from a single aquaculture cage in southern Chile. Interestingly, only two mtDNA haplotypes were obtained; however, several different MH alleles were detected, with divergence values that were compared with those of natural populations of salmonids. Thus, it seems evolutionary processes responsible of keeping MH diversity in the wild managed to retain MH variability in farmed Atlantic salmon, maintaining high immune diversity despite the generally lower levels of observed neutral genetic diversity.     

<Emphasis Type="Italic">Alternaria alternata</Emphasis> apple pathotype (<Emphasis Type="Italic">A. mali</Emphasis>) causes black spot of European pear

A disease caused by Alternaria alternata occurred on the leaves of European pear cultivar Le Lectier in Niigata Prefecture, Japan, and was named black spot of European pear. In conidial inoculation tests, the causal pathogen induced not only small black lesions on the leaves of European pear cultivar Le Lectier, but severe lesions on the leaves of apple cultivar Red Gold, which is susceptible to the A. alternata apple pathotype (previously called A. mali) causing Alternaria blotch of apple. Interestingly, the apple pathotype isolate showed the same pathogenicity as the European pear pathogen. HPLC analysis of the culture filtrates revealed that A. alternata causing black spot of European pear produced AM-toxin I, known as a host-specific toxin of the A. alternata apple pathotype. AM-toxin I induced veinal necrosis on leaves of Le Lectier and General Leclerc cultivars, both susceptible to the European pear pathogen, at 5?×?10^?7 M and 10^?6 M respectively, but did not affect leaves of resistant cultivars at 10^?4 M. PCR analysis with primers that specifically amplify the AM-toxin synthetase gene detected the product of expected size in the pathogen. These results indicate that A. alternata causing black spot of European pear is identical to that causing Alternaria blotch of apple. This is the first report of European pear disease caused by the A. alternata apple pathotype. This study provides a multiplex PCR protocol, which could serve as a useful tool, for the epidemiological survey of these two diseases in European pear and apple orchards.     

Deadwood volume in strictly protected,natural, and primeval forests in Poland

Standing and downed deadwood at different stages of decay provides a crucial habitat for a wide range of organisms. It is particularly abundant in unmanaged forests, such as strictly protected areas of national parks and nature reserves. The present work used the available data for such sites in Poland, analyzing a total of 113 studies concerning 79 sites to determine the causes contributing to variation in deadwood volume based on the duration of conservation, changes in deadwood volume over time (for those sites which were examined multiple times), elevation above sea level, forest type, stage of forest development, input of dead trees from the years preceding deadwood measurements, live tree volume, and the proportion of downed to standing deadwood). Depending on species composition and site altitude, most tree stands fell into one of four categories: subalpine spruce forests, montane beech-fir forests, low altitude beech-fir forests, or oak-hornbeam and riparian forests. The mean deadwood volume for all forest types amounted to 172.0 m³/ha. The mean volume of deadwood in montane beech-fir forests (223.9 m³/ha) was statistically significantly greater than in the other three forest types, for which it ranged from 103.5 to 142.5 m³/ha. A direct effect of the duration of conservation on deadwood volume was not identified. Nevertheless, analysis of repeated measurements on the same sample plots at 10-year intervals showed a consistent rise in mean deadwood volume. A linear regression model for all the analyzed factors reported from montane beech-fir forests and subalpine spruce forests showed that in addition to site altitude, another statistically significant variable was the input of dead trees (R²?=?63.54%).