Faecal shedding detected earlier than immune responses in goats naturally infected with Mycobacterium avium subsp. paratuberculosis

Paratuberculosis was diagnosed in a goat herd that participated in a sanitation program against Mycobacterium avium subsp. paratuberculosis. The aim of this study was to characterise the development of gamma interferon (IFN-γ) and antibody responses as well as the occurrence of faecal shedding. Faecal culture appeared surprisingly sensitive as about 18% and 40% of the goats were positive at 9 and 15-17 months of age, respectively, and shedding was often seen prior to peripheral immune responses. Peripheral IFN-γ responses were not related to protection as clinical and high shedding goats often had high responses. An IFN-γ response usually preceded a humoral response. However, positive antibody titers could sometimes be seen simultaneously with, and even prior to, IFN-γ responses. In conclusion, faecal culture appeared as sensitive as IFN-γ testing. Furthermore, the antibody ELISA and the IFN-γ assay may perform equally well in an infected herd if surveillance is conducted annually.     

盐胁迫对扁桃砧木叶片SOD、POD和CAT活性的影响

以温室盆栽的3种扁桃砧木为材料,研究了不同浓度的NaCl、Na2SO4和不同胁迫时间对其叶片活性氧代谢变化的影响.结果表明:NaCl和Na2SO4胁迫下,石头扁桃,桃扁桃和毛桃叶片中POD、CAT活性均随盐浓度的增加而升高,而随着盐胁迫时间的延长其活性有所下降,但都高于对照.SOD活性均随盐浓度的增加先升高后下降,而且后期下降幅度很大.与NaCl胁迫相比,Na2SO4胁迫下这3种砧木叶片中POD、CAT和SOD活性低.从2种盐胁迫下POD、CAT和SOD活性变化规律初步判断这3种砧木的抗盐能力强弱为桃扁桃＞毛桃＞石头扁桃.     

中国家鸡和红色原鸡mtDNA控制区遗传多态性及系统进化分析

通过线粒体DNA控制区的结构和多态性来研究中国家鸡和红色原鸡的遗传多态性与系统进化。测定14个中国地方鸡种和红色原鸡2个亚种的256个个体线粒体DNA控制区部分序列约560bp,结果表明,A、C、G、T这4种核苷酸的平均比例分别为25．∞％、37．40％、4．40％和33．20％。共发现44个变异位点,约占分析位点总数的7．86％,没有观测到插入／缺失,颠换和转换之比为0．13;共具有32种单倍型,9种为共享单倍型;16个群体内单倍型多样度从0到0．964,单倍型变异度总体为0．909±0．014,整体的平均核苷酸差异数为7．276,核苷酸多样度为1．851％。群体间核苷酸分歧度（Dxy）在0．747％～3．125％之间变化,核苷酸净遗传距离（Da）为0．015％～2．633％。16个群体表现出较高水平的遗传多态性,群体间表现出显著的遗传分化。群体遗传多态性和亲缘关系分析表明,一些中国家鸡的群体（如固始鸡和仙居鸡）起源于泰国红色原鸡Gallus gallu sgallus亚种,一些中国家鸡的群体（如茶花鸡和藏鸡等）起源于中国红色原鸡Gallus gallus spadiceus亚种,在一些中国地方鸡种还同时具有这2种红色原鸡的遗传贡献;认为中国家鸡起源于泰国或单纯起源于中国的观点都是不全面的。     

Congenital dyserythropoiesis and progressive alopecia in Polled Hereford calves: hematologic, biochemical, bone marrow cytologic, electrophoretic, and flow cytometric findings.

Congenital dyserythropoiesis with dyskeratosis is a slow, progressive, and often fatal disease in Polled Hereford calves. Affected calves have a macrocytic normochromic anemia with a mild reticulocytosis. Studies indicate that calves are hyperferremic with increased saturation of serum total iron binding capacity, which rules out iron deficiency as a cause. Other secondary causes of dyserythropoiesis, including cobalamin and folate deficiencies, are unlikely because serum cobalamin and folate levels of affected calves were normal. Virus isolation was negative, and failure to identify bovine retroviral antigens or antibodies from several calves suggested that viral agents were not involved. Bone marrow cytologic findings were similar to those in congenital hereditary dyserythropoiesis in humans and included occasional multinucleate cells, internuclear chromatin bridging between nuclei of partially divided cells, and, more frequently, irregular nuclear shapes and chromatin patterns. DNA content and cell cycle distribution of erythroid cells appeared normal, and no electrophoretic abnormalities were detected in erythrocyte membrane proteins. The Polled Hereford syndrome is similar in many ways to type I congenital dyserythropoiesis in humans and may be an appropriate biomedical model for studying erythroid proliferation during dyserythropoiesis.     

The environmental safety of eprinomectin to earthworms

A study was conducted to assess the environmental safety of the endectocide eprinomectin to the earthworm Lumbricus terrestris under conditions mimicking typical product use on pasture. The LC50 value of eprinomectin in artificial soil after 28 days of exposure is higher than the levels expected in feces from dosed cattle or in soil fertilized with manure from dosed cattle, which indicates a wide margin of safety for this compound to earthworms. However, the no-observed-effect concentration has not been established. Therefore, the current study was conducted to determine whether there would be any effects on earthworms from feces from cattle treated with the commercial formulation of eprinomectin. Feces were collected rectally from grazing cattle on Day 0 before treatment and on Days 2, 4, 7 and 14 after treatment with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle (Merial Limited) at 0.5 mg eprinomectin per kg bodyweight. Assays of eprinomectin B1a (the major component of eprinomectin) were 0, 0.427, 0.152, 0.0512 and 0.00185 mg kg-1 wet weight of feces (equivalent to 0, 3.34, 1.19, 0.40 and 0.010 mg kg-1 on a dry weight basis, respectively). No significant differences (p>0.05) were observed at any day post-treatment in the survival or behavioral effects of any worms fed post-dose feces relative to the worms fed control feces. All post-dose comparisons of weight changes of living earthworms to the control group were not significantly different (p>0.05), indicating that treatment of cattle with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle did not affect feeding or weight gain of the earthworms. The LC50 value and the results of this study establish the wide margin of safety afforded to earthworms by eprinomectin under typical usage conditions.     

Influence of carrot psyllid (Trioza apicalis) feeding or exogenous limonene or methyl jasmonate treatment on composition of carrot (Daucus carota) leaf essential oil and headspace volatiles

The effect of carrot psyllid (Trioza apicalis F?rster) feeding and limonene and methyl jasmonate (MeJA) treatments on the essential oil composition and headspace volatiles of carrot (Daucus carota ssp. sativus), cvs. Parano and Splendid, leaves was studied. Carrot psyllid feeding significantly increased the concentrations of sabinene, beta-pinene, and limonene, whereas limonene treatment increased the concentration of (Z)-beta-ocimene in the leaves of both cultivars. The limonene treatment significantly increased the concentration of total phenolics in the leaves of both cultivars, and MeJA treatment increased phenolic concentration in the leaves of Parano. Exogenous limonene spray did not decrease the number of carrot psyllid eggs laid either 2 or 24 h after treatment. The results suggest that carrot psyllid feeding induces changes in the endogenous monoterpene pool in the carrot leaves. Limonene and MeJA treatments affect some induced defenses of the carrot, but the exogenous limonene spray is not an effective oviposition deterrent against carrot psyllid.     

Changing stock of biomass carbon in a boreal forest over 93 years

The growing stock more than doubled from 1.6 to 3.4 million m³ between 1912 and 2005 in forests on an area of 387 km² in southern Finland. The stock expansion continued for 93 years noting interim results, which were available for 1959, 1982, 1994 and 1999. Forested area in the region hardly changed. Carbon sequestration was mainly a result of a long-term recovery from forest degradation, a legacy of land use in the 18th and 19th centuries. Tree demography responded to management change especially of mature stands: Average tree size and stocking density of stands increased. On average the expanding biomass stock sequestered 18 tons C annually per km² (18 g C per m²). In comparison, the emissions of fossil carbon in the region were estimated at 12 tons C per km² (12 g C per m²) on average. However, fossil CO₂ emissions exceeded biomass sequestration in recent decades. The powerful and persistent expansion of the carbon stock was an unintended co-benefit of forestry, which was motivated by the intention to improve timber yield. On the more negative side the change in management introduced clear-cuts, and a loss of diverse elements of the pre-industrial biota.     

Structural characteristics of a low Arctic tundra ecosystem and the retreat of the Arctic fox

We conducted a large-scale, campaign-based survey in Finnmark, northern Norway to evaluate the proposition that declining Arctic fox populations at the southern margin of the Arctic tundra biome result from fundamental changes in the state of the ecosystem due to climatic warming. We utilized the fact that the decline of the Arctic fox in Finnmark has been spatially heterogeneous by contrasting ecosystem state variables between regions and landscape areas (within regions) with and without recent Arctic fox breeding.Within the region of Varanger peninsula, which has the highest number of recorded dens and the most recent breeding records of Arctic fox, we found patterns largely consistent with a previously proposed climate-induced, bottom-up trophic cascade that may exclude the Arctic fox from tundra. Landscape areas surrounding dens without recent Arctic breeding were here more productive than areas with recent breeding in terms of biomass of palatable and climate sensitive plants, the number of insectivorous passerines and predatory skuas. Even the frequency of unspecified fox scats was the highest in landscape areas where arctic fox breeding has ceased, consistent with an invasion of the competitively dominant red fox. The comparisons made at the regional level were not consistent with the results within the Varanger region, possibly due to different causal factors or to deficiencies in Arctic fox monitoring at a large spatial scale. Thus long-term studies and adequate monitoring schemes with a large-scale design needs to be initiated to better elucidate the link between climate, food web dynamics and their relations to Arctic and red foxes.     

CX3CR1-mediated dendritic cell access to the intestinal lumen and bacterial clearance

Dendritic cells (DCs) and macrophages are critical to innate and adaptive immunity to the intestinal bacterial microbiota. Here, we identify a myeloid-derived mucosal DC in mice, which populates the entire lamina propria of the small intestine. Lamina propria DCs were found to depend on the chemokine receptor CX3CR1 to form transepithelial dendrites, which enable the cells to directly sample luminal antigens. CX3CR1 was also found to control the clearance of entero-invasive pathogens by DCs. Thus, CX3CR1-dependent processes, which control host interactions of specialized DCs with commensal and pathogenic bacteria, may regulate immunological tolerance and inflammation.     

Wood modification with alkoxysilanes

Wood was treated with three different alkoxysilanes which are able to undergo a sol–gel process: tetraethoxysilane (TEOS), methyl triethoxysilane (MTES) and propyl triethoxysilane (PTEO). Two types of treatments were compared: impregnation of fibre saturated wood with monomeric silane solutions, and impregnation with pre-hydrolysed partly oligomeric silanes. Wood properties such as cell wall bulking, anti-swelling efficiency (ASE), moisture uptake and durability were more significantly improved in samples treated with monomeric silanes than in samples treated with oligomeric silanes. SEM-EDX mapping showed that this treatment resulted in a higher degree of silicon incorporation into the cell wall, although the weight percent gain (WPG) was lower compared to the treatment with pre-hydrolysed partly oligomeric silanes. The resistance against soil micro-organisms was enhanced in the initial phase of incubation especially in those samples treated with organo-functional-alkoxysilanes. In miniaturised block tests with the white-rot basidiomycete Trametes versicolor, an improved durability was observed within the test period. During an air conditioning step, a weight loss of the treated samples occurred which was accompanied by a reduction in bulking and ASE. The initial reduction of moisture uptake observed after treatment diminished almost completely. This effect was explained by an ageing of the gels in the wood cell wall which is a consequence of uncompleted hydrolysis and condensation of the silanes during the treatment.