Seroprevalence and risk factors of Q fever in goats on commercial dairy goat farms in the Netherlands, 2009-2010

Background

Highly pathogenic avian influenza (HPAI) viruses have had devastating effects on poultry industries worldwide, and there is concern about the potential for HPAI outbreaks in the poultry industry in Great Britain (GB). Critical to the potential for HPAI to spread between poultry premises are the connections made between farms by movements related to human activity. Movement records of catching teams and slaughterhouse vehicles were obtained from a large catching company, and these data were used in a simulation model of HPAI spread between farms serviced by the catching company, and surrounding (geographic) areas. The spread of HPAI through real-time movements was modelled, with the addition of spread via company personnel and local transmission.

Results

The model predicted that although large outbreaks are rare, they may occur, with long distances between infected premises. Final outbreak size was most sensitive to the probability of spread via slaughterhouse-linked movements whereas the probability of onward spread beyond an index premises was most sensitive to the frequency of company personnel movements.

Conclusions

Results obtained from this study show that, whilst there is the possibility that HPAI virus will jump from one cluster of farms to another, movements made by catching teams connected fewer poultry premises in an outbreak situation than slaughterhouses and company personnel. The potential connection of a large number of infected farms, however, highlights the importance of retaining up-to-date data on poultry premises so that control measures can be effectively prioritised in an outbreak situation.     

Factor XIII Transglutaminase Supports the Resolution of Mucosal Damage in Experimental Colitis

The thrombin-activated transglutaminase factor XIII (FXIII) that covalently crosslinks and stablizes provisional fibrin matrices is also thought to support endothelial and epithelial barrier function and to control inflammatory processes. Here, gene-targeted mice lacking the FXIII catalytic A subunit were employed to directly test the hypothesis that FXIII limits colonic pathologies associated with experimental colitis. Wildtype (WT) and FXIII^-/- mice were found to be comparable in their initial development of mucosal damage following exposure to dextran sulfate sodium (DSS) challenge. However, unlike FXIII-sufficient mice, FXIII-deficient cohorts failed to efficiently resolve colonic inflammatory pathologies and mucosal damage following withdrawal of DSS. Consistent with prior evidence of ongoing coagulation factor activation and consumption in individuals with active colitis, plasma FXIII levels were markedly decreased in colitis-challenged WT mice. Treatment of colitis-challenged mice with recombinant human FXIII-A zymogen significantly mitigated weight loss, intestinal bleeding, and diarrhea, regardless of whether cohorts were FXIII-sufficient or were genetically devoid of FXIII. Similarly, both qualitative and quantitative microscopic analyses of colonic tissues revealed that exogenous FXIII improved the resolution of multiple colitis disease parameters in both FXIII^-/- and WT mice. The most striking differences were seen in the resolution of mucosal ulceration, the most severe histopathological manifestation of DSS-induced colitis. These findings directly demonstrate that FXIII is a significant determinant of mucosal healing and clinical outcome following inflammatory colitis induced mucosal injury and provide a proof-of-principle that clinical interventions supporting FXIII activity may be a means to limit colitis pathology and improve resolution of mucosal damage.     

In Vitro Induction of Regulatory CD4+CD8α+ T Cells by TGF-β, IL-7 and IFN-γ

In vitro CD4⁺ T cell differentiation systems have made important contributions to understanding the mechanisms underlying the differentiation of naive CD4⁺ T cells into effector cells with distinct biological functions. Mature CD4⁺ T cells expressing CD8αα homodimers are primarily found in the intestinal mucosa of men and mice, and to a lesser extent in other tissues such as peripheral blood. Although CD4⁺CD8α⁺ T cells are easily identified, very little is known about their development and immunological functions. It has been reported, however, that CD4⁺CD8α⁺ T cells possess regulatory properties. In this report, we present a novel in vitro differentiation system where CD4⁺ T cells are stimulated to become CD4⁺CD8α⁺ T cells in the presence of TGF-β, IL-7 and IFN-γ, resulting in cells with very similar features as CD4⁺CD8α⁺ intraepithelial lymphocytes. This novel in vitro differentiation culture should provide a powerful and tractable tool for dissecting the differentiation and biological functions of CD4⁺CD8α⁺ T cells.     

Quantification of dye-mediated photodamage during single-molecule DNA imaging

Single-molecule fluorescence imaging of DNA-binding proteins has enabled detailed investigations of their interactions. However, the intercalating dyes used to visually locate DNA molecules have the undesirable effect of photochemically damaging the DNA through radical intermediaries. Unfortunately, this damage occurs as single-strand breaks (SSBs), which are visually undetectable but can heavily influence protein behavior. We investigated the formation of SSBs on DNA molecules by the dye YOYO-1 using complementary single-molecule imaging and gel electrophoresis-based damage assays. The single-molecule assay imaged hydrodynamically elongated lambda DNA, enabling the real-time detection of double-strand breaks (DSBs). The gel assay, which used supercoiled plasmid DNA, was sensitive to both SSBs and DSBs. This enabled the quantification of SSBs that precede DSB formation. Using the parameters determined from the gel damage assay, we applied a model of stochastic DNA damage to the time-resolved DNA breakage data, extracting the rates of single-strand breakage at two dye staining ratios and measuring the damage reduction from the radical scavengers ascorbic acid and β-mercaptoethanol. These results enable the estimation of the number of SSBs that occur during imaging and are scalable over a wide range of laser intensities used in fluorescence microscopy.     

Polyamine auxotrophs of Saccharomyces cerevisiae.

Strains of yeast have been constructed that are unable to synthesize ornithine and are thereby deficient in polyamine biosynthesis. These strains were used to develop a protocol for isolation of mutants blocked directly in polyamine synthesis. There were seven mutants isolated that lack ornithine decarboxylase activity; these strains exhibited greatly decreased pool levels of putrescine, spermidine, and spermine when grown in the absence of polyamines. Three of the mutants lack S-adenosylmethionine decarboxylase activity; polyamine limitation of a representative mutant resulted in an accumulation of putrescine and a decrease in spermidine and spermine. When the mutants were cultured in the absence of polyamines, a continuously declining growth rate was observed.     

Deuterated docosahexaenoic acid protects against oxidative stress and geographic atrophy‐like retinal degeneration in a mouse model with iron overload

Oxidative stress plays a central role in age‐related macular degeneration (AMD). Iron, a potent generator of hydroxyl radicals through the Fenton reaction, has been implicated in AMD. One easily oxidized molecule is docosahexaenoic acid (DHA), the most abundant polyunsaturated fatty acid in photoreceptor membranes. Oxidation of DHA produces toxic oxidation products including carboxyethylpyrrole (CEP) adducts, which are increased in the retinas of AMD patients. In this study, we hypothesized that deuterium substitution on the bis‐allylic sites of DHA in photoreceptor membranes could prevent iron‐induced retinal degeneration by inhibiting oxidative stress and lipid peroxidation. Mice were fed with either DHA deuterated at the oxidation‐prone positions (D‐DHA) or control natural DHA and then given an intravitreal injection of iron or control saline. Orally administered D‐DHA caused a dose‐dependent increase in D‐DHA levels in the neural retina and retinal pigment epithelium (RPE) as measured by mass spectrometry. At 1 week after iron injection, D‐DHA provided nearly complete protection against iron‐induced retinal autofluorescence and retinal degeneration, as determined by in vivo imaging, electroretinography, and histology. Iron injection resulted in carboxyethylpyrrole conjugate immunoreactivity in photoreceptors and RPE in mice fed with natural DHA but not D‐DHA. Quantitative PCR results were consistent with iron‐induced oxidative stress, inflammation, and retinal cell death in mice fed with natural DHA but not D‐DHA. Taken together, our findings suggest that DHA oxidation is central to the pathogenesis of iron‐induced retinal degeneration. They also provide preclinical evidence that dosing with D‐DHA could be a viable therapeutic strategy for retinal diseases involving oxidative stress.     

栀子水提取物对实验性2型糖尿病大鼠血糖及同型半胱氨酸水平的影响

观察栀子提取物对实验性2型糖尿病大鼠血糖、血脂及同型半胱氨酸水平的影响.采用Wistar雄性大鼠70只,随机抽取10只作为正常对照组,喂以普通维持饲料,其余60只高糖高脂饲料喂养4周后,ip链脲佐菌素(STZ)30 mg/kg建立2型糖尿病模型,7d后选取成模大鼠50只随机分为模型对照组(生理盐水)、盐酸二甲双胍对照组、栀子提取物低、中、高剂量组(0.2、0.4、0.6 g/kg),每组10只.连续ig给药4周后,观察各组大鼠血糖、血脂及同型半胱氨酸水平等变化.栀子提取物ig能降低糖尿病大鼠的血糖、甘油三酯(TG)、胆固醇(TC)、低密度脂蛋白(LDLC),同时能升高高密度脂蛋白(HDLC),降低同型半胱氨酸水平.     

Automated sequencing of complete mitochondrial genomes from laser-capture microdissected samples

Mitochondrial DNA mutations have been related to both aging and a variety of diseases such as cancer. Due to the relatively small size of the genome (16 kb) and with the use of automated DNA sequencing, the entire genome can be sequenced from clinical specimens in days. We present a reliable approach to complete mitochondrial genome sequencing from laser-capture microdissected human clinical cancer specimens that overcome the inherent limitations of relatively small tissue samples and partial DNA degradation, which are unavoidable when laser-capture microdissection is used to attain pure populations of cells from heterogeneous tissues obtained from surgical procedures. The acquisition of sufficient template combined with a standard set of 18 pairs of PCR primers allows for the efficient amplification of the genome. Subsequent single-stranded amplification is performed using 36 sequencing primers, and samples are run on an ABI PRISM 3100 Genetic Analyzer. The use of this procedure should allow even investigators with little experience sequencing from clinical specimens success in complete mitochondrial genome sequencing.     

Assessment of the serodiagnostic potential of nine novel proteins from Mycobacterium tuberculosis

To identify antigens that would improve the accuracy of serological diagnosis of active tuberculosis, we cloned the genes encoding nine potentially immunogenic secreted or surface-associated proteins of Mycobacterium tuberculosis. Recombinant proteins were reacted with sera from HIV-negative individuals with extrapulmonary tuberculosis (EP-TB) or HIV-positive individuals with pulmonary tuberculosis (TBH). Specific and high level antibody responses were obtained for four recombinant proteins, of which antigen GST-822 was recognized by 60% of EP-TB and 42% of TBH and antigen MBP-506 was recognized by 45% of EP-TB and 61% of TBH. These results suggest that these proteins are strong candidates as subunits in a polyvalent serodiagnostic test.     

水分胁迫下发草(Deschampsia caespitosa)叶片脯氨酸及其代谢产物变化

以发草(Deschampsia caespitosa)为供试材料,通过盆栽模拟水分胁迫,研究重度干旱、中度干旱、轻度干旱、植物正常需水量(对照)、轻度水涝、中度水涝、重度水涝处理下发草叶片脯氨酸(Pro)积累状况及其代谢途径中底物、中间产物和关键酶的动态变化,以期从脯氨酸代谢途径对发草抗旱/涝机理进行初步探讨。结果显示,干旱和水涝胁迫前期发草叶片Pro含量显著升高,谷氨酸(Glu)和鸟氨酸(Orn)含量显著下降,Δ¹-吡咯琳-5-羧酸合成酶(P5CS)活性、鸟氨酸转氨酶(δ-OAT)活性、Δ¹-吡咯琳-5-羧酸还原酶(P5CR)活性均显著增强,而脯氨酸脱氢酶(ProDH)活性显著降低,表明干旱和水涝胁迫前期发草叶片通过脯氨酸合成代谢的加强和分解代谢的抑制共同积累脯氨酸,以缓解干旱和水涝胁迫产生的危害,Glu途径和Orn途径协同作用于叶片脯氨酸合成代谢过程。中度、轻度干旱和轻度水涝处理21 d后Pro含量趋于稳定,持续21 d的重度干旱处理和持续28 d的重度水涝处理时发草死亡,共同显示了发草对水涝和干旱具有较强的耐受性。结论为高寒沼泽湿地旱涝"共耐性"植物的研究提供理论基础,同时为利用发草开展退化高寒沼泽湿地植被恢复提供科学依据。