The mycoflora and toxicity of feedstuffs from a production plant in córdoba, Argentina

Feedstuffs used for poultry nutrition in Argentina were analyzed for fungal flora and natural incidence of mycotoxins. Survey of 120 samples of poultry feeds, taken from May 1998 to April 1999, showed the presence of 15 genera of filamentous fungi. The predominant genera wereFusarium spp. andPenicillium ssp., isolated in 67.5 % of the samples, followed byAspergillus spp. (57.5 %). Yeast, were significantly isolated from most of the samples. Species identification was carried down for the toxigenic genera. Fungal total counts of poultry feeds ranged from 2.0 × 10³ to 3.0 × 10⁵ CFU g^-1 The fungal total counts during two months of sampling, were slightly over the limit value of 1 × 105 CFU g^-1, which ensure the hygienic quality of the feed. Potentially toxicogenic species presented moderate mean colony counts. Many of the fungi isolated from poultry feeds are mycotoxin producers. Fumonisins had the highest incidence, and were found in 97 % of the analyzed samples followed by aflatoxin B₁ (46 %), zearalenone (18 %) and deoxynivalenol (6 %). On the co-occurrence of both carcinogenic mycotoxins, all of the FBs contaminated feed samples were co-contaminated with AFB₁. The results show the relevance of the samples screening for viable fungi propagules and the surveillance of their associated mycotoxins in poultry feeds.     

CLN6, which is associated with a lysosomal storage disease, is an endoplasmic reticulum protein

The neuronal ceroid lipofuscinoses (NCLs) are severe inherited neurodegenerative disorders affecting children. In this disease, lysosomes accumulate autofluorescent storage material and there is death of neurons. Five types of NCL are caused by mutations in lysosomal proteins (CTSD, CLN1/PPT1, CLN2/TTPI, CLN3 and CLN5), and one type is caused by mutations in a protein that recycles between the ER and ERGIC (CLN8). The CLN6 gene underlying a variant of late infantile NCL (vLINCL) was recently identified. It encodes a novel 311 amino acid transmembrane protein. Antisera raised against CLN6 peptides detected a protein of 30 kDa by Western blotting of human cells, which was missing in cells from some CLN6 deficient patients. Using immunofluorescence microscopy, CLN6 was shown to reside in the endoplasmic reticulum (ER). CLN6 protein tagged with GFP at the C-terminus and expressed in HEK293 cells was also found within the ER. Investigation of the effect of five CLN6 disease mutations that affect single amino acids showed that the mutant proteins were retained in the ER. These data suggest that CLN6 is an ER resident protein, the activity of which, despite this location, must contribute to lysosomal function.     

UTILLdb, a Pisum sativum in silico forward and reverse genetics tool

The systematic characterization of gene functions in species recalcitrant to Agrobacterium-based transformation, like Pisum sativum, remains a challenge. To develop a high throughput forward and reverse genetics tool in pea, we have constructed a reference ethylmethane sulfonate mutant population and developed a database, UTILLdb, that contains phenotypic as well as sequence information on mutant genes. UTILLdb can be searched online for TILLING alleles, through the BLAST tool, or for phenotypic information about mutants by keywords.     

红脂大小蠹Dendroctonus valens(Coleoptera,Scolytidae)和大唼蜡甲 Rhizophagus grandis(Coleoptera,Rhizophagidae)的耐寒性

红脂大小蠹 Dendroctonus valens LeConte (Red turpentine beetle,RTB)是近年来在中国爆发的入侵生物,在我国主要以老熟幼虫在油松伐桩和立木的根部越冬.室内测定昆虫的过冷却点(SCP)和短时间致死低温(LLT)是评价昆虫耐寒能力的重要方法.实验结果显示,红脂大小蠹越冬幼虫的平均过冷却点为一11.98±2.55℃,是一种耐冰冻的昆虫.红脂大小蠹的过冷却点在不同地理分布区的种群问有明显差异,老熟幼虫的过冷却点明显低于低龄幼虫,在越冬前和越冬后的幼虫问没有明显差异.红脂大小蠹幼虫在冬季至少町以忍受-23.5℃的大气温度安全越冬.从2001年开始引入我国的云杉大小蠹的捕食者大唼蜡甲(Rhizophagus grandis cyll.)幼虫的过冷却点为-18.05±2.76℃,低于红脂大小蠹所有虫态的过冷却点,说明比红脂大小蠹有更强的耐寒能力.     

How much can a T-cell antigen receptor adapt to structurally distinct antigenic peptides?

Binding degeneracy is thought to constitute a fundamental property of the T-cell antigen receptor (TCR), yet its structural basis is poorly understood. We determined the crystal structure of a complex involving the BM3.3 TCR and a peptide (pBM8) bound to the H-2K(bm8) major histocompatibility complex (MHC) molecule, and compared it with the structures of the BM3.3 TCR bound to H-2K(b) molecules loaded with two peptides that had a minimal level of primary sequence identity with pBM8. Our findings provide a refined structural view of the basis of BM3.3 TCR cross-reactivity and a structural explanation for the long-standing paradox that a TCR antigen-binding site can be both specific and degenerate. We also measured the thermodynamic features and biological penalties that incurred during cross-recognition. Our data illustrate the difficulty for a given TCR in adapting to distinct peptide-MHC surfaces while still maintaining affinities that result in functional in vivo responses. Therefore, when induction of protective effector T cells is used as the ultimate criteria for adaptive immunity, TCRs are probably much less degenerate than initially assumed.     

Malaria on the Guiana Shield: a review of the situation in French Guiana

In a climate of growing concern that Plasmodium falciparum may be developing a drug resistance to artemisinin derivatives in the Guiana Shield, this review details our current knowledge of malaria and control strategy in one part of the Shield, French Guiana. Local epidemiology, test-treat-track strategy, the state of parasite drug resistance and vector control measures are summarised. Current issues in terms of mobile populations and legislative limitations are also discussed.     

Bioaccumulation of selected metals in the gill,liver and muscle tissue of rednose labeo Labeo rosae from two impoundments on the Olifants River,Limpopo river system,South Africa

Metal concentrations in the gill, muscle and liver tissues of Labeo rosae from two impoundments, Loskop and Flag Boshielo dams on the Olifants River, were evaluated in 2011 to detect patterns in metal associations between tissues and impoundments. Elevated concentrations of Ba, Zn, B, Al, Si and Fe, relative to a pristine site in the catchment, were found in the muscle, liver and gill tissues at both impoundments. Molybdenum concentrations were exceptionally high in all tissues at Loskop Dam and in liver at Flag Boshielo Dam. No definite pattern in the ratio metal concentrations within, or between, fish tissues was identified. The expected trend, liver > gills > muscle, was found at both impoundments, but was less prominent at Loskop Dam. Metal concentrations in muscle of Loskop Dam fish were significantly higher than in those at Flag Boshielo Dam. The inverse was true for liver. The long-term impact of elevated metal concentrations on fish health at both impoundments raises concern.     

Atrial natriuretic factor in pregnancy and pregnancy-induced hypertension.

In normal pregnancy, cross-sectional clinical data do not consistently show plasma ANF concentration differences between early pregnancy and the nonpregnant state. Sequential data in the baboon (but not in rat) show a significant decrease in plasma ANF concentration and in cardiac filling pressures in early pregnancy. The latter data support the view that pregnancy is an underfill state secondary to a primary vasodilatation. Cross-sectional and longitudinal studies in normal pregnancy in humans show that plasma ANF levels tend rise to values that are, in the third trimester, higher than in the nonpregnant state. However, late postpartum sequential data (1.5-3 months) in humans do now show a significant drop in plasma ANF concentrations, suggesting that plasma ANF is not actually increased in normal pregnancy. In the baboon (but not in the rat) there is a steady rise in plasma ANF levels to values that are significantly higher in third trimester than before pregnancy. These data suggest that in human pregnancy, in contrast with the baboon, the plasma volume expansion induced by normal pregnancy is not sensed as such by the atria probably because of an isopressive adaptation of plasma volume to an enlarged vascular bed. However, acute decrease or increase of venous return induced by low sodium diet, changing position or infusion of isotonic saline are sensed as such by the atria in normal pregnancy as in the nonpregnant state.(ABSTRACT TRUNCATED AT 250 WORDS)