Molecular phylogeny of the New World Dipsadidae (Serpentes: Colubroidea): a reappraisal

We present a phylogenetic analysis of the New World dipsadids based on an expanded data matrix that includes 246 terminal taxa including 196 dipsadids. The species are sampled for eight genes (12S, 16S, cytb, nd2, nd4, bdnf, c‐mos, rag2). The data are explored using two distinct optimality procedures—maximum parsimony and maximum likelihood—and two alignment strategies—dynamic homology and static homology. Two previously unsampled dipsadid genera, Sordellina and Rhachidelus, are now included in the analysis. The definitions of the genera, Erythrolamprus, Clelia, Hypsirhynchus, Philodryas and Phimophis, and the tribes Alsophiini, Echinantherini and Conophiini, are revised. In order to maintain monophyly, the genus Umbrivaga is synonymized with Erythrolamprus, and two new genera are erected to accommodate Phimophis iglesiasi and Clelia rustica, as well as their closely related species. The West Indian genera Schwartzophis, Darlingtonia, Antillophis and Ocyophis are resurrected. © The Willi Hennig Society 2012.     

Improvement of Brazilian bioethanol production – Challenges and perspectives on the identification and genetic modification of new strains of Saccharomyces cerevisiae yeasts isolated during ethanol process

In Brazil, bioethanol is produced by sucrose fermentation from sugarcane by Saccharomyces cerevisiae in a fed-batch process that uses high density of yeast cells (15–25 % of wet weight/v) and high sugar concentration (18–22 % of total sugars). Several research efforts have been employed to improve the efficiency of this process through the isolation of yeasts better adapted to the Brazilian fermentation conditions. Two important wild strains named CAT-1 and PE-2 were isolated during the fermentation process and were responsible for almost 60 % of the total ethanol production in Brazil. However, in the last decade the fermentative substrate composition was much modified, since new sugar cane crops were developed, the use of molasses instead of sugar cane juice increase and with the prohibition of burning of sugarcane prior harvest. As consequence, these previously isolated strains are being replaced by new wild yeasts in most of ethanol plants. In this new scenario the isolation of novel better adapted yeasts with improved fermentative characteristics is still a big challenge. Here, we discuss the main aspects of Brazilian ethanol production and the efforts for the selection, characterization and genetic modifications of new strains with important phenotypic traits such as thermotolerance.     

The Pmr1 protein, the major yeast Ca2+-ATPase in the Golgi, regulates intracellular levels of the cadmium ion

Cadmium is a nonessential, highly toxic heavy metal that shows ionic properties similar to calcium. These ionic similarities imply that the cadmium ion, Cd²⁺, is a calcium ion, Ca²⁺, receptor-agonist, affecting the same biochemical pathways involved in Ca²⁺ homeostasis. In the yeast Saccharomyces cerevisiae , the PMC1 and PMR1 genes encode vacuolar and Golgi Ca²⁺-ATPases, respectively. The PMR1 protein product Pmr1p is involved in both Ca²⁺ and Mn²⁺ homeostasis. This study investigated the importance of Pmc1p and Pmr1p for Cd²⁺ cellular detoxification. Using the standard techniques of yeast molecular research and a multielemental procedure named particle-induced X-ray emission, Pmr1p was identified as a protein that directly participates in the detoxification of Cd²⁺, possibly through the secretory pathway. The results allow us to posit a model of Cd²⁺ detoxification where Pmr1p has a central role in cell survival in a Cd²⁺-rich environment.     

Genetic, geographic, and linguistic variation among South American Indians: possible sex influence.

To better understand the relationship between genetic variability, geographical distance, and linguistic affiliation in South Amerinds, and to elucidate whether the migration rate is the same for both sexes, spatial autocorrelation, Mantel's test, and F(ST) analyses were performed in four sets of populations and alleles (group 1: 48 populations, 12 alleles; group 2: 16 (all belonging to the Tupi linguistic group) and 12; group 3: 21 and 17; and group 4: 28 and 4 haplotypes). Groups 1-3 included blood group and protein (i.e., serum protein, red cell enzymes, and immunoglobulin systems), while group 4 was concerned with mitochondrial DNA (mtDNA) only. The latter set was also subjected to a molecular analysis of variance (AMOVA) evaluation. The frequencies of statistically significant correlograms were lower than those obtained in other populations when the blood groups and protein systems were considered, but 3 of the 4 mtDNA haplogroups gave suggestions of population structure. The variability in this organelle is also significantly correlated with language when geography is held constant. Migration per generation is generally low, but higher estimates were obtained for females. The AMOVA results suggest that populations whose members speak the same language are genetically homogeneous and may be viewed as the ultimate evolutionary unit at this level of analysis.     

Diversity and natural hybridization in a highly endemic species of Petunia (Solanaceae): a molecular and ecological analysis

Intrinsic reproductive barriers among the species of Petunia are weak and genetic isolation is obtained mainly by geographical separation and ecological diversification. The Serra do Sudeste region in the extreme south of Brazil is one of the centres of diversity of this genus and is characterized by the presence of species with different pollination syndromes. Petunia exserta is known only from four sandstone towers in a restricted area of this region (about 500 km(2)) and is characterized by its differentiated habitat (shelters in the sandstone towers) and by its floral characteristics adapted to ornithophily. In towers where this species is sympatric with the sphingophilous Petunia axillaris, phylogenetically close to P. exserta, we found plants with intermediate floral morphology, suggesting hybridization between them. To test this hypothesis and to better understand its consequences we analysed the sequences of the plastid trnH-psbA, trnS-trnG and psbB-psbH intergenic spacers in 121 individuals sampled all over the P. exserta distribution. The joint analysis of the three markers revealed 13 haplotypes and the network showed two main genetic clades, which probably represent the original gene pool of the two species in the region. In general, individuals of a given population presented the same haplotype, independently of phenotype, corroborating the hybridization hypothesis. Field observations suggest that hummingbirds are responsible for the interspecific gene flow. Analysis of molecular variance revealed high interpopulational diversity among the towers. The low gene flow between populations is possibly related to the autochoric seed dispersion system.     

Shape and size of red blood cells from the Pygoscelid penguins of Antarctica using atomic force microscopy

Antarctic biodiversity is evolutionarily complex, reflecting the extreme ambient conditions. Therefore, Antarctic organisms exhibit sophisticated adaptations in all organization levels, including organs, tissues, and cells. Since red blood cells (RBCs) travel through the vertebrates blood delivering O₂ to all tissues and organs and purging the unwanted CO₂, they represent an interesting model to investigate biological adaptations. We have used atomic force microscopy (AFM) to compare the shape and size of RBCs of the Pygoscelid penguins. A total of 18 landmarks were measured in AFM images. When analyzed individually, the parameters were not capable of discriminating the RBCs of each species. However, the simultaneous use of multiple parameters discriminated (74%) among the RBCs. In addition, the use of RBC measurements was sufficient to hierarchically cluster the species in accordance to other common and reliable phylogenetic strategies. In light of these results, the use of RBC characters could effectively benefit taxonomic inferences.     

Localisation of the Vacuolar Proton Pump (V-H+-ATPase) and Carbonic Anhydrase II in the Human Eccrine Sweat Gland

The localisation of the vacuolar proton pump (V-H+ -ATPase) and the enzyme carbonic anhydrase II (CAII) was investigated in the human eccrine sweat gland employing standard immunohistochemical techniques after antigen retrieval using microwave heat treatment and high pressure. The high-pressure antigen retrieval unmasked the presence of V-H+ -ATPase in the clear cells of the secretory coil, with a distribution similar to that previously observed for CAII. However, the dark cells were unreactive to both antibodies. In addition, heat and high-pressure antigen retrieval demonstrated the presence of CAII in the apical zone of luminal cells of the reabsorptive duct, a location not previously reported. The localisation of V-H+ -ATPase and CAII in the secretory coil clear cells suggests that the formation of HCO3- and H+ by carbonic anhydrase II and the transport of H+ by V-H+ -ATPase may play an role in sweat fluid secretion. Their presence at the apex of the duct cells indicates involvement in ductal ion reabsorption.     

Antioxidant, a pro-oxidant and cytotoxic effects of Achyrocline satureioides extracts

In this study we compared the antioxidant properties of five different extracts of different composition obtained from Achyrocline satureioides' inflorescences (Compositae), a widely used Brazilian folk medicinal herb. All of the extracts presented significant antioxidant potential identified by TRAP assay, which increased in the presence of human plasma. Characterization of the content of flavonoids in each extract showed that the FDP80 (ethanol 80%) and FFr (enriched flavonoid fraction) extracts contained a higher content of flavonoids. Cytotoxicity of the extracts as determined in Sertoli cell culture showed that FDP80 and FFr were highly toxic at most concentrations tested. The extracts induced a significant increase in lipid peroxidation levels in Sertoli cells. These results suggest that medicinal herb extracts that contain higher flavonoid concentrations and shows higher antioxidant protection in vitro might not always produce the greatest benefit.     

Intra- and intercontinental molecular variability of an Alu insertion in the 3' untranslated region of the LDLR gene

One-hundred three individuals from two Mongolian, two Siberian, and ten native American populations were studied in relation to a 340-bp sequence from an Alu insertion located in the 3' untranslated region of the LDLR gene. Seven haplotypes have been determined, and haplotype B1 was the most common, accounting for about half the sequences found. In general, diversity values are quite high, about 2.5 times higher than those found in other autosomal Alu sequences. Almost all (93%) of the variability occurs at the intrapopulation level, but the greatest among-group differentiation (6-8%) was found when we grouped in a single population all Native Americans plus Siberian Eskimos and Chukchi and compared them with Mongolians. This result is compatible with earlier mtDNA and Y-chromosome suggestions of a single origin for the first colonizers of the American continent. With this nuclear locus it was not possible to broadly distinguish between Central and South American natives. No evidence of selection or marked demographic changes was obtained with these data.     

Dynamic rearrangement of the filamentous actin network occurs during zoosporogenesis and encystment in the oomycete phytophthora cinnamomi

The organization of filamentous actin (F-actin) in living cells of the oomycete Phytophthora cinnamomi was determined during zoosporogenesis and zoospore encystment by microinjecting sporangia with fluorescently labeled phalloidin and observing resultant fluorescence by confocal microscopy. In multinucleate sporangia prior to the induction of cleavage, phalloidin labeling took the form of plaques which occurred mainly in the periphery of the sporangia. After induction of cleavage, phalloidin labeling showed that the plaques disappeared and that F-actin began to accumulate along the developing cleavage planes and around nuclei and water expulsion vacuoles. F-actin labeling was also observed near the plasma membrane in zoospores and young cysts but reverted to the plaque form in older cysts. Localization of F-actin close to the developing cleavage planes is consistent with the idea that actin microfilaments function in the positioning and expansion of the cleavage membranes. Observations of plaques of actin in living sporangia provide evidence that plaques are not aldehyde-induced fixation artifacts. Copyright 1998 Academic Press.