Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders

We analyzed mitotic and meiotic cells of a Brazilian amblypygid, Heterophrynus longicornis, using conventional and molecular cytogenetic techniques (Giemsa staining, C-banding, Ag-NOR, and FISH with rDNA probe). This is the first study that focuses solely on amblypygid chromosomes; it was undertaken to add data on cytogenetic knowledge of this group and contribute to the understanding of chromosome evolution in the Arachnida. We found 2n = 66 for male and female individuals, monocentric chromosomes, and absence of morphologically differentiated sex chromosomes. C-banding showed heterochromatin in the pericentromeric region of most chromosomes. Mitotic and meiotic nuclei submitted to silver impregnation and FISH revealed, respectively, Ag-NORs and ribosomal genes in the terminal region of two chromosome pairs. Most chromosome features that we observed in H. longicornis are shared with species of other arachnid orders; however, the absence of morphologically differentiated sex chromosomes in amblypygid contrasts with the remarkable variety of sex chromosome systems recorded for the Araneae. Consequently, we conclude that analysis of species of the Tetrapulmonata clade is useful for understanding the trends of sex chromosome evolution in this arachnid group. © FUNPEC-RP.

Morphological and molecular characterization and phylogenetic relationships of a new species of trypanosome in Tapirus terrestris (lowland tapir), Trypanosoma terrestris sp nov., from Atlantic Rainforest of southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cyclic codes through B[X;(a/b)Z_0, with (a/b) in Q^{+} and b=a+1, and Encoding

Let B[X; S] be a monoid ring with any fixed finite unitary commutative ring B and is the monoid S such that b = a + 1, where a is any positive integer. In this paper we constructed cyclic codes, BCH codes, alternant codes, Goppa codes, Srivastava codes through monoid ring . For a = 1, almost all the results contained in [16] stands as a very particular case of this study.

Chromosome mapping of retrotransposable elements Rex1 and Rex3 in Leporinus Spix, 1829 species (Characiformes: Anostomidae) and its relationships among heterochromatic segments and W sex chromosome

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Escherichia coli strains isolated from the uteri horn, mouth, and rectum of bitches suffering from pyometra: virulence factors, antimicrobial susceptibilities, and clonal relationships among strains

Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼ 50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans.

Karyologic diversification and phylogenetic relationships of the genus Thalpomys (Rodentia, Sigmodontinae)

We describe the karyotype of Thalpomys species, from different Brazilian localities of the Cerrado. Thalpomys cerradensis Herskovitz, 1990 showed 2n = 36, FN = 34 and T. lasiotis Thomas, 1916 2n = 38, FN = 38. Comparisons of G-band karyotypes showed evident inter-specific homologies indicating that their chromosome complements could be derived from one another by two presumed rearrangements. Both species showed pericentromeric C-band regions in almost all chromosomes but a comparison with CMA3/DA/DAPI staining indicated that the molecular content of heterochromatic regions was different. T. lasiotis specimens from two different localities differed in the morphology of the X chromosome due to the presence of a short heterochromatic arm. These chromosome types are apparently fixed in each population rather than maintained as a polymorphic variation. Phylogenetic analyses supported the monophyly of the genus Thalpomys but was not capable of elucidating its phylogenetic relationship to other Akodontini rodents. These analyses also showed inter-individual variation in T. lasiotis, even within a given population. Phylogenetic analyses placed T. lasiotis specimens with different karyotypes in different monophyletic branches. Molecular and karyologic data confirmed the identity of the genus Thalpomys.

Spatial relationships between soil attributes and corn yield in no-tillage system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Phylogenetic relationships of Pseudis and Lysapsus (Anura, Hylidae, Hylinae) inferred from mitochondrial and nuclear gene sequences

The previous uncertain placement of Lysapsus and Pseudis within the neobatrachians was recently resolved by molecular and morphological studies, which supported them as members of the Hylinae subfamily. Their inter- and intrageneric relationships, however, have long been under debate and no studies shed light on these questions. Aiming to elucidate such questions, this paper used 3.2 kb comprising the mitochondrial genes 12S, tRNA valine, 16S and cytochrome b, and the nuclear exon 1 coding for rhodopsin, to all representatives of both genera (except to two subspecies of Pseudis paradoxa). The results identified three major clades: the clade 1 was composed by Lysapsus species and subspecies; clade 2 included the subspecies of the Pseudis paradoxa (Pseudis paradoxa paradoxa, P. paradoxa platensis and P. paradoxa occidentalis), P. fusca, P. bolbodactyla and P. tocantins, and clade 3 was composed by Pseudis southern Brazil species (Pseudis cardosoi and P. minuta). As closely related taxa we found Pseudis minuta + P. cardosoi; P. tocantins + P. fusca, and the subspecies within each genus. Evidence that Pseudis is not monophyletic with respect to Lysapsus was found and we suggest Lysapsus to be a junior synonym of Pseudis. Based on pair-wise comparison among gene sequences, we also suggest that the subspecies of Pseudis paradoxa and Lysapsus limellum must be considered as full species. (c) the Willi Hennig Society 2007.

Reproductive relationships and degree of synapsis in the polytene chromosomes of the Drosophila buzzatii species cluster

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of management on plankton community of fishponds during the dry and rainy seasons

Aim: The present investigation aims at evaluating attention to the occurrence and abundance of planktonic communities in fishponds and their relationships to the management employed; Methods: Seven fishponds (V1-V7) fertilized with different treatments were analyzed by monthly sampling, taken between July and December/07, during both dry and rainy seasons; Results: Euglenophyceae and Chlorophyceae were most representative during the studied period. In the fishpond with organic fertilizer Cyanobacteria was more than 65 and 90% of total phytoplankton abundance in September and August, mainly represented by Microcystis sp. (14,595 and 22,500 ind.L-1, respectively). An inverse relationship occurred between Copepoda and Cladocera, and Copepoda and Rotifera were present in all fishponds during the both seasons. Diversity (H') and species richness was low and equitability indices generally showed the highest values for zooplankton. The lowest values were observed for phytoplankton during the rainy season; Conclusions: The use of organic fertilizer and the random emptying of the fishponds affected directly and species diversity and richness, with dominance of Cyanobacteria emphasizing the need to adopt a management technique to increase fishponds productivity and consequently, fish production.

Nesting architecture and population structure of the fungus-growing ant Cyphomyrmex transversus (Formicidae: Myrmicinae: Attini) in the Brazilian coastal zone of Ilheus, Bahia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Habitat use, reproductive traits and social interactions in a stream-dweller treefrog endemic to the Brazilian Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Phenotypical characterization and adhesin identification in Escherichia coli strains isolated from dogs with urinary tract infections

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cardiovascular changes under normoxic and hypoxic conditions in the air-breathing teleost Synbranchus marmoratus: importance of the venous system

Synbranchus marmoratus is a facultative air-breathing fish, which uses its buccal cavity as well as its gills for air-breathing. S. marmoratus shows a very pronounced tachycardia when it surfaces to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause a decline in stroke volume (VS), but this can be compensated for by an increase in venous tone to maintain stroke volume. Thus, the study on S. marmoratus was undertaken to investigate how stroke volume and venous function are affected during air-breathing. To this end we measured cardiac output (Q), heart rate (fH), central venous blood pressure (PCV), mean circulatory filling pressure (MCFP), and dorsal aortic blood pressures (PDA) in S. marmoratus. Measurements were performed in aerated water (P-O2 > 130 mmHg), when the fish alternated between gill ventilation and prolonged periods of apnoeas, as well as during hypoxia (P-O2 <= 50 mmHg), when the fish changed from gill ventilation to air-breathing. Q increased significantly during gill ventilation compared to apnoea in aerated water through a significant increase in both fH and VS. PCV and MCFP also increased significantly. During hypoxia, when the animals surface to ventilate air, we found a marked rise in fH, PCV, MCFP, Q and VS, whereas PDA decreased significantly. Simultaneous increases in PCV and MCFP in aerated, as well as in hypoxic water, suggests that the venous system plays an important regulatory role for cardiac filling and VS in this species. In addition, we investigated adrenergic regulation of the venous system through bolus infusions of adrenergic agonists (adrenaline, phenylephrine and isoproterenol; 2 mu g kg(-1)). Adrenaline and phenylephrine caused a marked rise in PCV and MCFP, whereas isoproterenol led to a marked decrease in PCV, and tended to decrease MCFP. Thus, it is evident that stimulation of both alpha- and beta-adrenoreceptors affects venous tone in S. marmoratus.