Risk factors associated with negative in-vivo diagnostic results in bovine tuberculosis-infected cattle in Spain

Background

Despite great effort and investment incurred over decades to control bovine tuberculosis (bTB), it is still one of the most important zoonotic diseases in many areas of the world. Test-and-slaughter strategies, the basis of most bTB eradication programs carried out worldwide, have demonstrated its usefulness in the control of the disease. However, in certain countries, eradication has not been achieved due in part to limitations of currently available diagnostic tests. In this study, results of in-vivo and post-mortem diagnostic tests performed on 3,614 animals from 152 bTB-infected cattle herds (beef, dairy, and bullfighting) detected in 2007–2010 in the region of Castilla y León, Spain, were analyzed to identify factors associated with positive bacteriological results in cattle that were non-reactors to the single intradermal tuberculin test, to the interferon-gamma (IFN-γ) assay, or to both tests applied in parallel (Test negative/Culture + animals, T-/C+). The association of individual factors (age, productive type, and number of herd-tests performed since the disclosure of the outbreak) with the bacteriology outcome (positive/negative) was analyzed using a mixed multivariate logistic regression model.

Results

The proportion of non-reactors with a positive post-mortem result ranged from 24.3% in the case of the SIT test to 12.9% (IFN-γ with 0.05 threshold) and 11.9% (95% CI 9.9-11.4%) using both tests in parallel. Older (>4.5 years) and bullfighting cattle were associated with increased odds of confirmed bTB infection by bacteriology, whereas dairy cattle showed a significantly lower risk. Ancillary use of IFN-γ assay reduced the proportion of T-/C + animals in high risk groups.

Conclusions

These results demonstrate the likelihood of positive bacteriological results in non-reactor cattle is influenced by individual epidemiological factors of tested animals. Increased surveillance on non-reactors with an increased probability of being false negative could be helpful to avoid bTB persistence, particularly in chronically infected herds. These findings may aid in the development of effective strategies for eradication of bTB in Spain.     

G protein-dependent CCR5 signaling is not required for efficient infection of primary T lymphocytes and macrophages by R5 human immunodeficiency virus type 1 isolates

The requirement of human immunodeficiency virus (HIV)-induced CCR5 activation for infection by R5 HIV type 1 (HIV-1) strains remains controversial. Ectopic CCR5 expression in CD4(+)-transformed cells or pharmacological inhibition of G(alpha)i proteins coupled to CCR5 left unsolved whether CCR5-dependent cell activation is necessary for the HIV life cycle. In this study, we investigated the role played by HIV-induced CCR5-dependent cell signaling during infection of primary CD4-expressing leukocytes. Using lentiviral vectors, we restored CCR5 expression in T lymphocytes and macrophages from individuals carrying the homozygous 32-bp deletion of the CCR5 gene (ccr5 Delta32/Delta32). Expression of wild-type (wt) CCR5 in ccr5 Delta32/Delta32 cells permitted infection by R5 HIV isolates. We assessed the capacity of a CCR5 derivative carrying a mutated DRY motif (CCR5-R126N) in the second intracellular loop to work as an HIV-1 coreceptor. The R126N mutation is known to disable G protein coupling and agonist-induced signal transduction through CCR5 and other G protein-coupled receptors. Despite its inability to promote either intracellular calcium mobilization or cell chemotaxis, the inactive CCR5-R126N mutant provided full coreceptor function to several R5 HIV-1 isolates in primary cells as efficiently as wt CCR5. We conclude that in a primary, CCR5-reconstituted CD4(+) cell environment, G protein signaling is dispensable for R5 HIV-1 isolates to actively infect primary CD4(+) T lymphocytes or macrophages.     

A novel SR-related protein is required for the second step of Pre-mRNA splicing

The SR family proteins and SR-related polypeptides are important regulators of pre-mRNA splicing. A novel SR-related protein of an apparent molecular mass of 53 kDa was isolated in a gene trap screen that identifies proteins which localize to the nuclear speckles. This novel protein possesses an arginine- and serine-rich domain and was termed SRrp53 (for SR-related protein of 53 kDa). In support for a role of this novel RS-containing protein in pre-mRNA splicing, we identified the mouse ortholog of the Saccharomyces cerevisiae U1 snRNP-specific protein Luc7p and the U2AF65-related factor HCC1 as interacting proteins. In addition, SRrp53 is able to interact with some members of the SR family of proteins and with U2AF35 in a yeast two-hybrid system and in cell extracts. We show that in HeLa nuclear extracts immunodepleted of SRrp53, the second step of pre-mRNA splicing is blocked, and recombinant SRrp53 is able to restore splicing activity. SRrp53 also regulates alternative splicing in a concentration-dependent manner. Taken together, these results suggest that SRrp53 is a novel SR-related protein that has a role both in constitutive and in alternative splicing.     

伊比利亚河共生的当年生鳟和埃布罗河鳟的夏季摄食关系

1996-1998年8月在Larraun河(埃布罗河流域,西班牙北部)共捕获306尾埃布罗河(鱼岁)和185尾0龄的鳟,分析比较了胃含物组成,并测定了种间的食物重叠.食物的个数百分比组成表明两种都主要摄食水生无脊椎动物.摄食策略图显示两种都是摄食不同食物 种类的广食性种类.另外,比较胃含物和底栖大型无脊椎动物群落表明,0龄的鳟和埃布罗河(鱼岁)不摄食光螺科、钩虾科、细蜉科、 四节蜉科和卷襀科的物种,而喜食摇蚊科、五节蜉科和毛翅目物种.尽管简化的Morisitas指数表明Larraun河中这两种鱼之间的食物重叠是显著的,但由于栖息地不同和摄食的可塑性可以降低种间的竞争,使得该水域的这两种鱼能以相对较大的数量共存.然而,在食物资源和可用栖息地有限的河域,埃布罗河(鱼岁)的引入,其适应性和可塑性有可能威胁单独存在的鳟     

Alkylation damage in DNA and RNA--repair mechanisms and medical significance

Alkylation lesions in DNA and RNA result from endogenous compounds, environmental agents and alkylating drugs. Simple methylating agents, e.g. methylnitrosourea, tobacco-specific nitrosamines and drugs like temozolomide or streptozotocin, form adducts at N- and O-atoms in DNA bases. These lesions are mainly repaired by direct base repair, base excision repair, and to some extent by nucleotide excision repair (NER). The identified carcinogenicity of O(6)-methylguanine (O(6)-meG) is largely caused by its miscoding properties. Mutations from this lesion are prevented by O(6)-alkylG-DNA alkyltransferase (MGMT or AGT) that repairs the base in one step. However, the genotoxicity and cytotoxicity of O(6)-meG is mainly due to recognition of O(6)-meG/T (or C) mispairs by the mismatch repair system (MMR) and induction of futile repair cycles, eventually resulting in cytotoxic double-strand breaks. Therefore, inactivation of the MMR system in an AGT-defective background causes resistance to the killing effects of O(6)-alkylating agents, but not to the mutagenic effect. Bifunctional alkylating agents, such as chlorambucil or carmustine (BCNU), are commonly used anti-cancer drugs. DNA lesions caused by these agents are complex and require complex repair mechanisms. Thus, primary chloroethyl adducts at O(6)-G are repaired by AGT, while the secondary highly cytotoxic interstrand cross-links (ICLs) require nucleotide excision repair factors (e.g. XPF-ERCC1) for incision and homologous recombination to complete repair. Recently, Escherichia coli protein AlkB and human homologues were shown to be oxidative demethylases that repair cytotoxic 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) residues. Numerous AlkB homologues are found in viruses, bacteria and eukaryotes, including eight human homologues (hABH1-8). These have distinct locations in subcellular compartments and their functions are only starting to become understood. Surprisingly, AlkB and hABH3 also repair RNA. An evaluation of the biological effects of environmental mutagens, as well as understanding the mechanism of action and resistance to alkylating drugs require a detailed understanding of DNA repair processes.     

DNA barcoding and minibarcoding as a powerful tool for feather mite studies

Feather mites (Astigmata: Analgoidea and Pterolichoidea) are among the most abundant and commonly occurring bird ectosymbionts. Basic questions on the ecology and evolution of feather mites remain unanswered because feather mite species identification is often only possible for adult males, and it is laborious even for specialized taxonomists, thus precluding large‐scale identifications. Here, we tested DNA barcoding as a useful molecular tool to identify feather mites from passerine birds. Three hundred and sixty‐one specimens of 72 species of feather mites from 68 species of European passerine birds from Russia and Spain were barcoded. The accuracy of barcoding and minibarcoding was tested. Moreover, threshold choice (a controversial issue in barcoding studies) was also explored in a new way, by calculating through simulations the effect of sampling effort (in species number and species composition) on threshold calculations. We found one 200‐bp minibarcode region that showed the same accuracy as the full‐length barcode (602 bp) and was surrounded by conserved regions potentially useful for group‐specific degenerate primers. Species identification accuracy was perfect (100%) but decreased when singletons or species of the Proctophyllodes pinnatus group were included. In fact, barcoding confirmed previous taxonomic issues within the P. pinnatus group. Following an integrative taxonomy approach, we compared our barcode study with previous taxonomic knowledge on feather mites, discovering three new putative cryptic species and validating three previous morphologically different (but still undescribed) new species.     

Thymic alterations in EphA4-deficient mice

In the present work, we have demonstrated in vivo an altered maturation of the thymic epithelium that results in defective T cell development which increases with age, in the thymus of Eph A4-deficient mice. The deficient thymi are hypocellular and show decreased proportions of double-positive (CD4+CD8+) cells which reach minimal numbers in 4-wk-old thymi. The EphA4 (-/-) phenotype correlates with an early block of T cell precursor differentiation that results in accumulation of CD44-CD25+ triple-negative cells and, sometimes, of CD44+CD25- triple-negative thymocytes as well as with increased numbers of apoptotic cells and an important reduction in the numbers of cycling thymocytes. Various approaches support a key role of the thymic epithelial cells in the observed phenotype. Thymic cytoarchitecture undergoes profound changes earlier than those found in the thymocyte maturation. Thymic cortex is extremely reduced and consists of densely packed thymic epithelial cells. Presumably the lack of forward Eph A4 signaling in the Eph A4 -/- epithelial cells affects their development and finally results in altered T cell development.     

Cognitive impairment and the risk of falling in the elderly

Risk of fall is significantly increased in old people with cognitive decline due to specific associations between gait parameters and cognition. This association has recently been demonstrated, there being increasing evidence that cognitive domains such as attention, executive function and types of memory are critical for the correct regulation of gait. Gait disturbances can appear as early predictors of dementia in elderly patients. In the assessment of the fall risk, the use of dual tasks is novel, simple and relevant, especially in cognitive decline. Evidence for interventions in this population is limited, with vitamin D and physical exercise being the most encouraging, for decreasing the risk of fall in dementia.