A taxonomic survey of lactic acid bacteria isolated from wheat (Triticum durum) kernels and non-conventional flours

In order to explore the correspondence between raw material- and mature sourdough-lactic acid bacterial (LAB) communities, 59 Italian wheat (Triticum durum) grain samples, one bran and six non-conventional flour samples were analyzed through a culture-dependent approach. The highest cell count by an agar medium specific for LAB was 2.16 log CFU/g. From about 2300 presumptive LAB (Gram-positive and catalase-negative) colonies collected, a total of 356 isolates were subjected to identification by a genetic polyphasic strategy consisting of RAPD-PCR analysis, partial 16S rRNA gene sequencing, species-specific and multiplex PCRs. The isolates were recognized as 137 strains belonging to Aerococcus, Enterococcus, Lactobacillus, Lactococcus and Pediococcus genera and a phylogram based on partial 16S rRNA genes was constructed. The species most frequently found were Enterococcus faecium, Enterococcus mundtii and Lactobacillus graminis, which are not generally reported to be typical in mature sourdoughs.     

Relationship of aerobic and anaerobic parameters with 400 m front crawl swimming performance

The aims of the present study were to investigate the relationship of aerobic and anaerobic parameters with 400 m performance, and establish which variable better explains long distance performance in swimming. Twenty-two swimmers (19.1±1.5 years, height 173.9±10.0 cm, body mass 71.2±10.2 kg; 76.6±5.3% of 400 m world record) underwent a lactate minimum test to determine lactate minimum speed (LMS) (i.e., aerobic capacity index). Moreover, the swimmers performed a 400 m maximal effort to determine mean speed (S400m), peak oxygen uptake (V.O2PEAK) and total anaerobic contribution (C_ANA). The C_ANA was assumed as the sum of alactic and lactic contributions. Physiological parameters of 400 m were determined using the backward extrapolation technique (V.O2PEAK and alactic contributions of C_ANA) and blood lactate concentration analysis (lactic anaerobic contributions of C_ANA). The Pearson correlation test and backward multiple regression analysis were used to verify the possible correlations between the physiological indices (predictor factors) and S400m (independent variable) (p < 0.05). Values are presented as mean ± standard deviation. Significant correlations were observed between S400m (1.4±0.1 m·s^-1) and LMS (1.3±0.1 m·s^-1; r = 0.80), V.O2PEAK (4.5±3.9 L·min^-1; r = 0.72) and C_ANA (4.7±1.5 L·O₂; r= 0.44). The best model constructed using multiple regression analysis demonstrated that LMS and V.O2PEAK explained 85% of the 400 m performance variance. When backward multiple regression analysis was performed, C_ANA lost significance. Thus, the results demonstrated that both aerobic parameters (capacity and power) can be used to predict 400 m swimming performance.     

Effects of density and predation risk on leaf litter processing by Phylloicus sp.

The allochthonous detritus that accumulates in the substrate of streams is used by aquatic invertebrate shredders for shelter and food. Shredders are considered rare in tropical systems, and little information is available about the role of density effects and predation risk (associated with the perception of predators by prey) in relationship to the resources used by these organisms. The aim of this study was to examine experimentally the effects of increased predation risk and of the density of Phylloicus sp. (i.e. of two types of biological relationships) on the processing of the leaf litter of Nectandra megapotamica (Spreng.) Mez. Phylloicus sp. can use leaf litter for case building and as a food resource. The density effect was measured using four treatments that differed only in the number of individuals (one, two, three or four). A second experiment with five treatments was performed to test the risk of non‐lethal predation on detritus consumption (shelter and food) by Phylloicus sp. (T1: Caddisfly; T2: Mayfly; T3: Astyanax sp./fish; T4: Damselflies; T5: Stonefly). A single Phylloicus and one other organism (a potential predator blocked with 0.5 mm fine mesh) were placed in each tank (0.002 m³ volume). We observed a negative effect of density on per capita litter consumption (experiment 1). The low density of Phylloicus may be a natural factor that decreases intraspecific competition. In the presence of fish, Phylloicus showed the lowest amount of litter processing observed in the experiment, indicating top‐down control (experiment 2). In treatments that involved the presence of invertebrates (non‐predatory and predatory), Phylloicus showed the highest amount and an intermediate amount of leaf litter processing, respectively (experiment 2). This observation also suggests that the predation effect is more probable for specific predator–prey pairs. Population density and predation risk in Phylloicus may be important factors controlling leaf litter processing.     

Expression of follicle-stimulating hormone receptor (FSHR) in goat ovarian follicles and the impact of sequential culture medium on in vitro development of caprine preantral follicles

This study evaluated the expression of FSH receptors (FSHR) in the different stages of goat follicle development and investigated whether the addition of increasing concentrations of FSH throughout the culture period influences the survival, growth and antral formation of in vitro-cultured caprine preantral follicles. The expression of FSHR was analysed before and after culturing follicles using real-time RT-PCR. For the culture, preantral follicles (≥150 μm) were isolated from ovarian fragments and cultured for 18 days in α-MEM+ alone or associated with recombinant FSH (rFSH: 100 or 1000 ng/ml), or in α-MEM+ supplemented with increasing concentrations of FSH throughout culture periods as follows: (a) sequential medium 1: FSH 100 ng/ml (from day 0 to 6), FSH 500 ng/ml (from day 6 to 12) and FSH 1000 ng/ml (from day 12 to 18); and (b) sequential medium 2: FSH 500 ng/ml (from day 0 to 9) and 1000 ng/ml (from day 9 to 18). Follicle development was evaluated on the basis of antral cavity formation, follicular and oocyte growth, and cumulus-oocyte complex health. The expression of FSHR in isolated caprine follicles increased from the preantral to antral phase. Regarding the culture, after 18 days, sequential medium 1 promoted follicular survival, antrum formation and a reduction in oocyte extrusion. Both sequential media promoted a higher rate of meiotic resumption compared with the other treatments. In conclusion, the addition of increased concentrations of FSH (sequential medium) has a significant impact on the in vitro development of caprine preantral follicles.     

Infection with Leishmania amazonensis upregulates purinergic receptor expression and induces host-cell susceptibility to UTP-mediated apoptosis

Nucleotides are released into the extracellular milieu from infected cells and cells at inflammatory sites. The extracellular nucleotides bind to specific purinergic (P2) receptors and thereby induce a variety of cellular responses including anti-parasitic effects. Here we investigated whether extracellular nucleotides affect leishmanial infection in macrophages, and found that UTP reduces strongly the parasite load in peritoneal macrophages. Ultrastructural analysis of infected cells revealed that UTP induced morphological damage in the intracellular parasites. Uridine nucleotides also induced dose-dependent apoptosis of macrophages and production of ROI and RNI only in infected macrophages. The intracellular calcium measurements of infected cells showed that the response to UTP, but not UDP, increased the sensitivity and amplitude of cytosolic Ca(2+) changes. Infection of macrophages with Leishmania upregulated the expression of P2Y(2) and P2Y(4) receptor mRNA. The data suggest indirectly that Leishmania amazonensis infection induces modulation and heteromerization of P2Y receptors on macrophages. Thus UTP modulates the host response against L. amazonensis infection. UTP and UTP homologues should therefore be considered as novel components of therapeutic strategies against cutaneous leishmaniasis.     

Genetic analysis of two Portuguese populations of <Emphasis Type="Italic">Ruditapes decussatus</Emphasis> by RAPD profiling

The clam Ruditapes decussatus is commercially important in the south of Portugal. The random amplified polymorphic DNA (RAPD) technique was applied to assess the genetic diversity and population structure of two Portuguese populations occurring in the Ria Formosa (Faro) and the Ria de Alvor, respectively. Twenty-five individuals of each population were investigated by RAPD profiles. Genetic diversity within populations, measured by the percentage of polymorphic loci (%P), varied between 68.57% (Alvor) and 73.88% (Faro). Shannon’s information index (H) and Nei’s gene diversity (h) were 0.281 and 0.176, respectively, for the Alvor population and 0.356 and 0.234 for the Faro population. Overall, genetic variation within R. decussatus populations was high. The total genetic diversity (H _T) was explained by a low variation between populations (G _ST = 0.145), which is consistent with high gene flow (N _m = 2.9). The analysis of molecular variance (AMOVA) showed that 65% of variability is within populations and 35% between populations (Φ_PT = 0.345; P ≥ 0.001). The value of Nei’s genetic distance was 0.0881, showing a low degree of population genetic distance, despite the different geographic origin. This is the first study on the population genetics of R. decussatus by RAPD technique. The results may be useful for restocking programs and aquaculture.