Structural remodelling of the heart valves extracellular matrix during embryo development

Alterations in heart valve development represent more than 20% of congenital cardiovascular malformations. Most of the functional properties of heart valves depend on extracellular matrix. Despite its relevance, little is known about fibrillar components on developing stages. Our objective is to define histological changes on valves fibrillar components in late embryonic development of Mus musculus. We found type III collagen as the predominant fibre type in the ECM in prenatal stages followed by a switch to a type I predominance for postnatal ages. The change in fibrillar components is necessary to support the normal mechanical function of adult heart valves.     

The nature and dynamics of bacterial genomes

Though generally small and gene rich, bacterial genomes are constantly subjected to both mutational and population-level processes that operate to increase amounts of functionless DNA. As a result, the coding potential of bacterial genomes can be substantially lower than originally predicted. Whereas only a single pseudogene was included in the original annotation of the bacterium Escherichia coli, we estimate that this genome harbors hundreds of inactivated and otherwise functionless genes. Such regions will never yield a detectable phenotype, but their identification is vital to efforts to elucidate the biological role of all the proteins within the cell.     

Seroprevalence and isolation of Toxoplasma gondii from free-range chickens from Espírito Santo state, southeastern Brazil

Prevalence of Toxoplasma gondii infection in 510 free-range (FR) chickens (380 from 33 small farms, and 130 from a slaughter house for FR chickens) from Espírito Santo state, southeastern Brazil, was investigated. Antibodies to T. gondii were sought using commercial indirect haemagglutination (IHAT, Imuno-HAI Toxo(?), Wama Diagnóstica, S?o Paulo, Brazil, cut-off 1:16) and the modified agglutination test (MAT, cut-off 1:25) tests. Attempts were made to isolate viable T. gondii from seropositive chickens by bioassay in mice. Pooled samples of brain, heart and quadriceps muscle of one thigh (total 40 g) from 64 chickens with IHAT titers of ≥ 1:16 were minced, digested in pepsin and bioassayed in mice. Antibodies to T. gondii were found in 40.4% (206/510) FR chickens by IHAT (titer ≥ 1:16) and 38.8% (198/510) by MAT (titer ≥ 1:25); concordance between IHAT and MAT was 81.6% (kappa index=0.614). Viable T. gondii was isolated (designated TgCkBr234-281) from 48 of 64 (75%) seropositive (IHAT titers ≥ 1:32) FR chickens. Most isolates of T. gondii were virulent for mice; 100% of mice inoculated with 44 of 48 isolates died of toxoplasmosis within 30 days post inoculation (p.i). An epidemiological investigation revealed that people living in rural areas have little knowledge about the parasite and about the risk of acquiring it from raw meat. Results indicated that the locally available IHAT was useful for screening of chicken sera for T. gondii antibodies.     

Food safety implications of ochratoxin A in animal-derived food products

Ochratoxin A (OTA) is an important mycotoxin with potential to reach the human food chain through carry-over of contaminated, mostly cereal-based, feed into animal-derived products. Certain population groups, such as infants and children, are intensive and relatively restricted consumers of some animal-derived products, particularly milk and other dairy products, which may become contaminated with OTA. This review examines the literature on the occurrence of OTA in animal-derived products and discusses the public health and food safety implications of consumption of these products. The risk of OTA contamination of meat, milk, blood and derived products is discussed.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Mossoró, Rio Grande do Norte, Brazil

Toxoplasma gondii is an obligate intracellular parasite with a variety of hosts, responsible for reproductive problems and economic losses in sheep flocks. Neospora caninum was recently identified and its clinical presentation in sheep is similar to that of toxoplasmosis, which can cause repeated abortions, though less frequently in this species. In order to confirm the prevalence of these agents in the city of Mossoró, Rio Grande do Norte, Brazil, 409 serum samples from adult sheep (364 females and 45 males) were tested by the indirect immunofluorescence antibody test, using cut-off point at a dilution of 1:64 and 1:50 for T. gondii and N. caninum, respectively. From the 35 properties examined, 23 (65.7%) had at least one seropositive animal for T. gondii and six (17.1%) for N. caninum. The prevalence of seropositive animals for T. gondii was 20.7% and for N. caninum 1.8%. There was no association between the presence of the agent’s antibody and gender, reports of reproductive problems and presence of dogs and/or cats in the properties. T. gondii is well distributed and N. caninum has low prevalence in sheep and in the properties of the studied region.     

Properties of an aged phenanthrene-contaminated soil and its response to bioremediation processes

Purpose  

Persistent organic compounds exhibit declining extractability and bioavailability to microorganisms and other soil organisms with increasing contact time or ageing. Among the possible mechanisms are the association of organic compounds with natural organic matter. Ageing can reduce the negative effects that an organic pollutant may have on the biological, biochemical properties and phytotoxicity of the contaminated soil. The aim of the present work was to evaluate, under laboratory conditions, the response of an agricultural soil contaminated with phenanthrene (Phe) and subjected to 2-year ageing and the effects and potential remediation capabilities of compost and an effective Phe-degrading bacterial culture.     

Characterization of aflatoxigenic and non-aflatoxigenic strains of <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> isolated from corn grains of different geographic origins in Brazil

Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B₁, while 47.2% aflatoxins B₁ and B₂. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson’s correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB₁ and AFB₂, but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.     

The effects of obesity and fatty acids on the feline immune system

Obesity is a rising problem in cats. It is a risk factor for several diseases and has been linked to impaired immunity. The goal of this study was to determine the effect of body composition and effects of diet on immune function in cats. Twenty-eight short-term obese and 12 lean cats with equal gender distribution were evenly and randomly divided into two groups which were either fed a diet containing saturated (SFA) or long-chain n-3 polyunsaturated fatty acids (3-PUFA) for a period of 6 months prior to testing. Blood was collected by venipuncture from the jugular vein. Blood samples were analyzed in a double blind fashion. A complete blood count was performed and lymphocyte distribution was examined by flow cytometric analysis with specific fluorescein-conjugated subset markers. Immune function was measured as follows: the proliferative activity of different cellular fractions was tested with polyclonal mitogens such as lipopolysaccharide (LPS), phytohaemagglutinin (PHA), phorbol 12-myristate 13-acetate (PMA), Ca ionophore, and concanavalin A. Innate immune functions assessed were phagocytosis and natural killer cell (NK) cytotoxicity. A similar immune innate and adaptive immune response was elicited regardless of diet or body condition. However, there was no correlation between body condition, diet, and any of the quantitative and qualitative functional responses of the immune system. We conclude that short-term obesity and the fatty acid composition of the diet do not alter immune responses in cats.     

Changes in Lipid Composition After In-Vitro Selection for Glyphosate Tolerance in Tobacco

After a one-step selection procedure with glyphosate added to the callus medium, tobacco regenerants were obtained from calluses surviving on field doses of the herbicide. The lipid and sterol compositions of potted plants from the two original cultivars which underwent the selection procedure but without glyphosate, and the selected regenerants were investigated. Controls were derived from micropropagation and not from seeds. They served as appropriate controls for comparison with glyphosate regenerants, i.e. they underwent exactly the same experimental conditions except for the glyphosate treatment. Plant regeneration was strongly (at one-step selection) or fully (at stepwise selection) inhibited. Only a few glyphosate-tolerant plants (seven of Nevrokop A₂₄ and five of Zlatna arda) were obtained which were cloned and potted. At least 10 plants of one clone per genotype were used for the further biochemical analyses. The spraying of the tobacco plants from the cultivars with glyphosate led to a decrease of monogalactosyl diacylglycerol content and increase of the saturated fatty acids in all glycolipid classes. The concentration of stigmasterol increased and that of sitosterol decreased only in Zl.arda variety. In the regenerants there were different changes in lipid composition, concerning mainly a decrease of monogalactosyl diacylglycerols (MGDG) and an increase of digalactosyl diacylglycerols (DGDG) in Zl.arda-derived regenerants and increase of the amounts of neutral lipids and decrease of phospholipids (PL) in the Nevrokop A₂₄-derived regenerants. Surprisingly, after treatment of the regenerants with glyphosate, the MGDG amounts in these regenerants were higher than in the controls, which could mean a lesser ability to control ion permeability.