Genetics and telemetry indicate unexpected movements among structured populations for Brachyplatystoma platynemum in the Amazon

The genetic analysis of Brachyplatystoma platynemum individuals sampled from the lower Madeira River reinforces the existence of two structured populations in the Amazon Basin (Madeira and Amazon populations). However, the recapture of an individual from the Amazon population in the Solimões River, which was telemetry-tagged in the Madeira River after the damming, indicates that fish from the Amazon population move between the two river systems. This has not yet been observed, however, in the Madeira River population, which is currently divided and isolated in the lower and upper Madeira River by the construction of two dams.     

Fat absorptive processes in the intestine of the Antarctic fish Notothenia coriiceps (Richardson, 1844)

Absorption of lipids by the enterocytes of Notothenia coriiceps, an omnivorous Antarctic and subAntarctic fish, was studied by light and electron microscopy. The lipids are absorbed by the anterior and middle intestine segments. They appear as fat droplets that measure from 0.5 to 7 μm of diameter and which accumulate in the apical cytoplasm within the first 24 h and seem to be the main fat storage form in the enterocytes. Fat is also observed as lipid particles with 60–300 nm inside the rough endoplasmic reticulum and cytoplasmic smooth vesicles. The epithelial intercellular space and the mucosal inner lamina contain lipid particles, which probably are the fat transport form. Our observations show that an intense lipid absorptive process takes place in N. coriiceps digestive system, due to the great extension of the intestine involved and due to the great lipid accumulation found in the epithelial compartment.     

Evidence that dams promote biotic differentiation of zooplankton communities in two Brazilian reservoirs

Hydrobiologia - Human activities may change beta diversity—the spatial variation in species composition—in different ways. Positive and negative trends in beta diversity are referred as...     

Novel avenues for passion fruit in vitro regeneration from endosperm culture,and morpho-agronomic and physiological traits of triploid Passiflora cincinnata Mast. emblings

The present study describes a new regeneration system based on somatic embryogenesis from mature endosperm Passiflora cincinnata Mast. cultures. Moreover, the morpho-agronomic and phenological traits, as well as enzymatic activity of regenerated triploid emblings are compared to those of diploids. Mature endosperms were cultured on Murashige and Skoog medium supplemented with various concentrations (4.5–45.2 µM) of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.5 μM 6-benzylaminopurine (BA). No plant growth regulators were included in the control group. Embryogenic calli were observed only in treatments supplemented with 13.6 and 18.1 µM 2,4-D?+?4.5 µM BA, with the highest number of somatic embryos per explant and regenerated plants (emblings) obtained with 18.1 µM 2,4-D. Most emblings (70%) were triploid (2n?=?3x?=?27), with a DNA amount (4.38 pg) similar to that of endosperm and 1.5 times greater than in diploid P. cincinnata seedlings (2n?=?2x?=?18), that contained 2.98 pg of DNA. While the number of organs and/or structures was akin to that in diploids, triploid emblings generally exhibited larger and longer vegetative and floral structures. The flower lifespan was also slightly altered by triploidy, nectar concentration was 27% higher, and the activity of plant defense enzymes β-1,3-glucanase and polyphenol oxidase was 29.8% and 22.1% higher. This study describes a new regeneration system for the production of phenotypic variants of this ornamental passion fruit species, opening new perspectives for future studies on genetic passion fruit breeding.

     

Update on the application of magnetic fields to microalgal cultures

Coenzyme Q₁₀ (CoQ₁₀) is the main CoQ species in human and is used extensively in food, cosmetic and medicine industries because of its antioxidant properties and its benefit in prophylactic medicine and therapy for a variety of diseases. Among various approaches to increase the production of CoQ₁₀, microbial fermentation is the most effective. As knowledge of the biosynthetic enzymes and regulatory mechanisms modulating CoQ₁₀ production increases, opportunities arise for metabolic engineering of CoQ₁₀ in microbial hosts. In this review, we present various strategies used up to date to improve CoQ₁₀ production and focus on metabolic engineering of CoQ₁₀ overproduction in microbes. General strategies of metabolic engineering include providing sufficient precursors for CoQ₁₀, increasing metabolic fluxes, and expanding storage capacity for CoQ₁₀. Based on these strategies, CoQ₁₀ production has been significantly improved in natural CoQ₁₀ producers, as well as in heterologous hosts.

     

Isolation, Characterization and Antifungal Activity of Proteinase Inhibitors from Capsicum chinense Jacq. Seeds

Capsicum species belong to the Solanaceae family and have great social, economic and agronomical significance. The present research presents data on the isolation and characterization of Capsicum chinense Jacq. peptides which were scrutinized in relation to their toxicity towards a diverse set of yeast species. The protein extract was separated with C18 reverse-phase chromatography in high performance liquid chromatography, resulting in three different peptide enriched fractions (PEFs) termed PEF1, PEF2 and PEF3. Tricine-SDS-PAGE of the PEF2 revealed peptides with molecular masses of approximately 5.0 and 8.5 kDa. These PEFs also exhibited strong antifungal activity against different yeasts. In the presence of the PEF2, Candida tropicalis exhibited morphological changes, including cellular agglomeration and formation of pseudohyphae. Determined N-terminal sequences of PEF2 and PEF3 were proven to be highly homologous to serine proteinase inhibitors, when analysed by comparative database sequence tools. For this reason were performed protease inhibitory activity assay. The PEFs displayed high inhibitory activity against trypsin and low inhibitory activity against chymotrypsin. PEF2 and PEF3 were considerably unsusceptible to a broad interval of pH and temperatures. Due to the myriad of application of Proteinase inhibitors (PIs) in fields ranging from plant protection against pathogens and pests to medicine such as in cancer and virus replication inhibition, the discovery of new PIs with new properties are of great interest.     

Length–weight relationships for fishes caught by shrimp trawl in Santa Catarina coast,south Atlantic,Brazil

Length–weight relationships (TW = a TL^b) were estimated for fish species caught by bottom shrimp trawl north of Santa Catarina Island (Brazil) from October 2003 to September 2004. For three of the species this is the first LWR data in Brazil.     

Application of modified Salmonella/microsome prescreen to petroleum-derived complex mixtures and polynuclear aromatic hydrocarbons (PAH)

In some cases, the Salmonella mutagenicity assay may fail to predict the carcinogenic potential of PAH (and of complex mixtures containing PAH) because of nonoptimal in vitro metabolic activation parameters. In this study, 7 petroleum-derived complex mixtures, as well as a number of individual PAH which were representative constituents of such mixtures, were tested in a Salmonella prescreen using quadrant plates with rat or hamster S9 at concentrations approximately 2-8 times those used in the standard assay. Some PAH (perylene, quinoline, benzo[b]chrysene, phenanthrene, anthracene) were optimally activated to mutagens by S9 at 400 microliters/plate. Rat S9 was similar to hamster S9 for most tested PAH, but anthracene and quinoline mutagenicity was enhanced by hamster S9. All 7 complex mixtures were more mutagenic with 200-400 microliters/plate S9; rat was generally slightly more efficient than hamster. Modifying this assay to include a prescreen using a range of S9 concentrations (and perhaps from species other than rat) may improve prediction of the potential carcinogenicity of complex petroleum-derived mixtures.     

Familial breast/ovarian cancer and BRCA1/2 genetic screening: the role of immunohistochemistry as an additional method in the selection of patients.

Only 20-25% of families screened for BRCA1/2 mutations are found positive. Because only a positive result is informative, we studied the role of BRCA1/2 immunohistochemistry as an additional method for patient selection. From 53 high-risk-affected probands, 18 (34%) had available paraffin blocks of their tumors and were selected for this study. Mutation screening was done by conformation-sensitive gel electrophoresis and multiplex ligation-dependent probe amplification. For immunohistochemistry, 21 neoplastic specimens (15 breast carcinomas, 5 ovary neoplasms, and 1 rectal adenocarcinoma) were analyzed with BRCA1 (monoclonal antibody, Ab-1, oncogene) and BRCA2 (polyclonal antibody, Ab-2, oncogene) antibodies. Absence of the BRCA1 protein was confirmed in negative tumors by Western blotting. Seven patients were positive for BRCA1/2 mutations: 5 for BRCA1 and 2 for BRCA2. Four out of five positive patients had tumors negative for BRCA1 immunostaining, and the remaining 13 BRCA1-negative patients had positive BRCA1 immunostaining in all tumor samples. Sensitivity to predict for BRCA1 mutation carriers was 80%, and specificity was 100%, with a positive predictive value of 100% and a negative predictive value of 93%. This correlation was statistically significant (p=0.001). No correlation was observed for BRCA2. If larger studies confirm these results, high-risk patients with BRCA1-negative tumors should be screened first for this gene.