Atividade antibacteriana do Aspergillus niger van Tieghem, 1867; pesquisas em 14 amostras da National Collection of Type Cultures (M. R. C.)

1. Pesquisamos a atividade antibacteriana em 14 amostras de Aspergillus niger da National Collection of Type Cultures. 2. Em meio de Raulin e Mosseray, sete amostras apresentaram atividade total, nunca superior a 1:10, contra Staphylococcus aureus nº 553, sendo que as amostras 1.161 e 2.390 permaneceram ativas por mais de 40 dias. 3. A utilização do meio de Czapek-Dox com 5% de "corn-steep" não melhorou os resultados obtidos com o meio de Raulin e Mosseray. 4. No meio de levedo peptonado, todas as amostras apresentaram-se inativas.

Endogeneizing know-how flows through the nature of R&D investments

In this paper we carefully link knowledge flows to and from a firms innovation process with this firms investment decisions. Three types of investments are considered: investments in applied research, investments in basic research, and investments in intellectual property protection. Only when basic research is performed, can the firm effectively access incoming knowledge flows and these incoming spillovers serve to increase the efficiency of own applied research.. The firm can at the same time influence outgoing knowledge flows, improving appropriability of its innovations, by investing in protection. Our results indicate that firms with small budgets for innovation will not invest in basic research. This occurs in the short run, when the budget for know-how creation is restricted, or in the long-run, when market opportunities are low, when legal protection is not very important, or, when the pool of accessible and relevant external know-how is limited. The ratio! of basic to applied research is non-decreasing in the size of the pool of accessible external know-how, the size and opportunity of the market, and, the effectiveness of intellectual property rights protection. This indicates the existence of economies of scale in basic research due to external market related factors. Empirical evidence from a sample of innovative manufacturing firms in Belgium confirms the economies of scale in basic research as a consequence of the firms capacity to access external knowledge flows and to protect intellectual property, as well as the complementarity between legal and strategic investments.

Restriction site-associated DNA sequencing, genotyping error estimation and de novo assembly optimization for population genetic inference.

Restriction site-associated DNA sequencing (RADseq) provides researchers with the ability to record genetic polymorphism across thousands of loci for nonmodel organisms, potentially revolutionizing the field of molecular ecology. However, as with other genotyping methods, RADseq is prone to a number of sources of error that may have consequential effects for population genetic inferences, and these have received only limited attention in terms of the estimation and reporting of genotyping error rates. Here we use individual sample replicates, under the expectation of identical genotypes, to quantify genotyping error in the absence of a reference genome. We then use sample replicates to (i) optimize de novo assembly parameters within the program Stacks, by minimizing error and maximizing the retrieval of informative loci; and (ii) quantify error rates for loci, alleles and single-nucleotide polymorphisms. As an empirical example, we use a double-digest RAD data set of a nonmodel plant species, Berberis alpina, collected from high-altitude mountains in Mexico.

Competitive displacement of Biomphalaria glabrata by B. straminea

Data on the interaction between populations of closely related species of Biomphalaria, B. glabrata and B. straminea, are presented in the current paper. Laboratory and field observations and experiments have shown that B. straminea has competitive advantages over B. glabrata.

Effect of vitamin D on Epstein-Barr (EBV)-specific CD8+T cells in patients with early multiple sclerosis (MS)

Background: Infection with EBV and a lack in vitamin D may be important environmental triggers of MS. 1,25-(OH)2D3 mediates a shift of antigen presenting cells (APC) and CD4+ T cells to a less inflammatory profile. Although CD8+ T cells do express the vitamin D receptor, a direct effect of 1,25(OH)2D3 on these cells has not been demonstrated until now. Since CD8+ T cells are important immune mediators of the inflammatory response in MS, we examined whether vitamin D directly affects the CD8+ T cell response, and more specifically if it modulates the EBV-specific CD8+ T cell response. Material and Methods: To explore whether the vitamin D status may influence the pattern of the EBV-specific CD8+ T cell response, PBMC of 10 patients with early MS and 10 healthy controls (HC) were stimulated with a pool of immunodominant 8-10 mer peptide epitopes known to elicit CD8+ T cell responses. PBMC were stimulated with this EBV CD8 peptide pool, medium (negative control) or anti- CD3/anti-CD28 beads (positive control). The following assays were performed: ELISPOT to assess the secretion of IFN-gamma by T cells in general; cytometric beads array (CBA) and ELISA to determine whichcytokines were released by EBV-specific CD8+ T cells after six days of culture; and intracellular cytokine staining assay to determine by which subtype of T cells secreted given cytokines. To examine whether vitamin D could directly modulate CD8+ T cell immune responses, we depleted CD4+ T cells using negative selection. Results: We found that pre-treatment of vitamin D had an antiinflammatory action on both EBV-specific CD8+ T cells and on CD3/ CD28-stimulated T cells: secretion of pro-inflammatory cytokines (IFNgamma and TNF-alpha) was decreased, whereas secretion of antiinflammatory cytokines (IL-5 and TGF-beta) was increased. At baseline, CD8+ T cells of early MS patients showed a higher secretion of TNFalpha and lower secretion of IL-5. Addition of vitamin D did not restore the same levels of both cytokines as compared to HC. Vitamin D-pretreated CD8+T cells exhibited a decreased secretion of IFN-gamma and TNF-alpha, even after depletion of CD4+ T cells from culture. Conclusion: Vitamin D has a direct anti-inflammatory effect on CD8+ T cells independently from CD4+ T cells. CD8+ T cells of patients with earlyMS are less responsive to the inflammatory effect of vitamin D than HC, pointing toward an intrinsic dysregulation of CD8+ T cells. The modulation of EBV-specific CD8+T cells by vitaminDsuggests that there may be interplay between these twomajor environmental factors of MS. This study was supported by a grant from the Swiss National Foundation (PP00P3-124893), and by an unrestricted research grant from Bayer to RDP.

Fecundity of Biomphalaria straminea and B. glabrata in the laboratory: a twelve-month comparative study

In the present comparative study a Biomphalaria straminea sample from Picos (Piauí) showed expressive advantages related to fecundity over a B. glabrata sample from Belo Horizonte (Minas Gerais) such as: higher egg-mass production in 10 out of 12 months of study; higher egg production in all months of study; higher egg per egg-mass ratio in 11 out of 12 months of study; 66% of the egg-masses containing more than 20 eggs while in B. glabrata 70% of the egg-masses showed less than 20 eggs; three times less empty egg capsules than B. glabrata; attainning maximum fecundity in half the time required by B. glabrata. Mortality however was higher and sooner in B. straminea, suggesting higher semelparity in this species than in B. glabrata, a possibility that requires confirmation through long-term studies with other samples of both species. This first finding of a B. straminea sample more fecund than B. glabrata is discussed in relation to other data from the literature, and some recommendations are made on the quantification of fecundity of planorbid snails.

Effect of temperature on different stages of Romanomermis iyengari, a mermithid nematode parasite of mosquitoes

The effect of temperature (20 degrees-35 degrees C) on different stages of Romanomermis iyengari was studied. In embryonic development, the single-cell stage eggs developed into mature eggs in 4.5-6.5 days at 25-35 degrees C but, required 9.5 days at 20 degrees C. Complete hatching occurred in 7 and 9 days after egg-laying at 35 and 30 degrees C, respectively. At 25 and 20 degrees C, 85-96 of the eggs did not hatch even by 30th day. Loss of infectivity and death of the preparasites occurred faster at higher temperatures. The 50 survival durations of preparasites at 20 and 35 degrees C were 105.8 and 10.6 hr respectively. They retained 50 infectivity up to 69.7 and 30.3 hr. The duration of the parasitic phase increased as temperature decreased. Low temperature favoured production of a higher proportion of females which were also larger in size. The maximum time taken for the juveniles to become adults was 14 days at 20 degrees C and the minimum was 9 days at 35 degrees C. Oviposition began earlier at higher temperature than at lower temperature. However, its fecundic period was shorter at 20 degrees C than at 35 degrees C indicating enhanced rate of oviposition at 20 degrees C. Fecundity was adversely affected at 20 degrees C and 35 degrees C. It is shown that the temperature range of 25 degrees-30 degrees C favours optimum development of R. iyengari.

Dominant negative MyD88 proteins inhibit interleukin-1beta /interferon-gamma -mediated induction of nuclear factor kappa B-dependent nitrite production and apoptosis in beta cells.

Insulin-dependent diabetes mellitus is an autoimmune disease in which pancreatic islet beta cells are destroyed by a combination of immunological and inflammatory mechanisms. In particular, cytokine-induced production of nitric oxide has been shown to correlate with beta cell apoptosis and/or inhibition of insulin secretion. In the present study, we investigated whether the interleukin (IL)-1beta intracellular signal transduction pathway could be blocked by overexpression of dominant negative forms of the IL-1 receptor interacting protein MyD88. We show that overexpression of the Toll domain or the lpr mutant of MyD88 in betaTc-Tet cells decreased nuclear factor kappaB (NF-kappaB) activation upon IL-1beta and IL-1beta/interferon (IFN)-gamma stimulation. Inducible nitric oxide synthase mRNA accumulation and nitrite production, which required the simultaneous presence of IL-1beta and IFN-gamma, were also suppressed by approximately 70%, and these cells were more resistant to cytokine-induced apoptosis as compared with parental cells. The decrease in glucose-stimulated insulin secretion induced by IL-1beta and IFN-gamma was however not prevented. This was because these dysfunctions were induced by IFN-gamma alone, which decreased cellular insulin content and stimulated insulin exocytosis. These results demonstrate that IL-1beta is involved in inducible nitric oxide synthase gene expression and induction of apoptosis in mouse beta cells but does not contribute to impaired glucose-stimulated insulin secretion. Furthermore, our data show that IL-1beta cellular actions can be blocked by expression of MyD88 dominant negative proteins and, finally, that cytokine-induced beta cell secretory dysfunctions are due to the action of IFN-gamma.

A low stringency polymerase chain reaction approach to the identification of Biomphalaria glabrata and B. tenagophila, intermediate snail hosts of Schistosoma mansoni in Brazil

The low stringency-polymerase chain reaction (LS-PCR) with a pair of specific primers for the amplification of the 18S rRNA gene was evaluated as a means of differentiating between the two Schistosoma mansoni intermediate host species in Brazil: Biomphalaria glabrata and B. tenagophila. Individual snails obtained from different states of Brazil were used and the amplification patterns obtained showed a high degree of genetic variability in these species. Nevertheless, 4 and 3 clearly defined specific diagnostic bands was observed in individuals from B. glabrata and B. tenagophila respectively. The detection of snail specific diagnostic bands suggests the possibility of reliable species differentiation at the DNA level using LS-PCR.

Restriction site-associated DNA sequencing, genotyping error estimation and de novo assembly optimization for population genetic inference.

Restriction site-associated DNA sequencing (RADseq) provides researchers with the ability to record genetic polymorphism across thousands of loci for nonmodel organisms, potentially revolutionizing the field of molecular ecology. However, as with other genotyping methods, RADseq is prone to a number of sources of error that may have consequential effects for population genetic inferences, and these have received only limited attention in terms of the estimation and reporting of genotyping error rates. Here we use individual sample replicates, under the expectation of identical genotypes, to quantify genotyping error in the absence of a reference genome. We then use sample replicates to (i) optimize de novo assembly parameters within the program Stacks, by minimizing error and maximizing the retrieval of informative loci; and (ii) quantify error rates for loci, alleles and single-nucleotide polymorphisms. As an empirical example, we use a double-digest RAD data set of a nonmodel plant species, Berberis alpina, collected from high-altitude mountains in Mexico.

Opening statement by Mr Michael Scanlan, Secretary General of the Department of Health & Children at the meeting of the DÃil Committee of Public Accounts on 7th May 2009

Opening statement by Mr Michael Scanlan, Secretary General of the Department of Health & Children at the meeting of the Dáil Committee of Public Accounts on 7th May 2009 Click here to download PDF 37kb