The Sperm Of Hexagenia (pseudeatonica) Albivitta Walker (ephemeroptera: Fossoriae: Ephemeridae)

This study describes the sperm morphology of the mayfly Hexagenia (Pseudeatonica) albivitta (Ephemeroptera). Its spermatozoon measures approximately 30 μm of which 9 μm corresponds to the head. The head is composed of an approximately round acrosomal vesicle and a cylindrical nucleus. The nucleus has two concavities, one in the anterior tip, where the acrosomal vesicle is inserted and a deeper one at its base, where the flagellum components are inserted. The flagellum is composed of an axoneme, a mitochondrion and a dense rod adjacent to the mitochondrion. A centriolar adjunct is also observed surrounding the axoneme in the initial portion of the flagellum and extends along the flagellum for at least 2 μm, surrounding the axoneme in a half-moon shape. The axoneme is the longest component of the flagellum, and it follows the 9+9+0 pattern, with no central pair of microtubules. At the posterior region of the flagellum, the mitochondrion has a dumb-bell shape in cross sections that, together with the rectangular mitochondrial-associated rod, is responsible for the flattened shape of the flagellum. An internal membrane is observed surrounding both mitochondrion and its associated structure.

Molecular systematics of Thorea (Rhodophyta, Thoreales) species in Brazil

This study aimed to evaluate species level taxonomy and phylogenetic relationship among Thorea species in Brazil and other regions of the world using two molecular markers - RUBISCO large subunit plastid gene (rbcL) and nuclear small-subunit ribosomal DNA (SSU rDNA). Three samples of Thorea from Brazil (states of Mato Grosso do Sul and São Paulo) and one sample from Dominican Republic (DR) were sequenced. Analyses based on partial sequences of rbcL (1,282 bp) and complete sequences of SSU (1,752 bp) were essentially congruent and revealed that Thoreales formed a distinct monophyletic clade, which had two major branches with high support, representing the genera Thorea and Nemalionopsis. Thorea clade had four main branches with high support for all analyses, each one representing the species: 1) T. gaudichaudii C. Agardh from Asia (Japan and Philippines) - this clade occurred only in the rbcL analyses; 2) T. violacea Bory from Asia (Japan) and North America (U.S.A. and DR); 3) T. hispida (Thore) Desvaux from Europe (England) and Asia (Japan); 4) a distinct group with the three Brazilian samples (sequence identity: rbcL 97.2%, 1,246 bp; SSU 96.0-98.1%, 1,699-1,720 bp). The Brazilian samples clearly formed a monophyletic clade based on both molecular markers and was interpreted as a separate species, for which we resurrected the name T. bachmannii Pujals. Morphological and molecular evidences indicate that the Thoreales is well-resolved at ordinal and generic levels. In contrast, Thorea species recognized by molecular data require additional characters (e.g. reproductive and chromosome numbers) to allow consistent and reliable taxonomic circumscription aiming at a world revision based on molecular and morphological evidences.

Use of chromosome microdissection in fish molecular cytogenetics

Chromosome microdissection is a technique in which whole chromosomes or chromosomal segments are dissected under an inverted microscope yielding chromosome-specific sequences. Several protocol modifications introduced during the past 15 years reduced the number of chromosomes required for most applications. This is of particular interest to fish molecular cytogenetics, since most species present highly uniform karyotypes which make impossible the collection of multiple copies of the same chromosome. Probes developed in this manner can be used to investigate chromosome homologies in closely related species. Here we describe a protocol recently used in the gymnotiform species group Eigenmannia and review the major steps involved in the generation of these markers focusing on protocol modifications aiming to reduce the number of required chromosomes.

Cytogenetic characterization of the strongly electric Amazonian eel, Electrophorus electricus (Teleostei, Gymnotiformes), from the Brazilian rivers Amazon and Araguaia

A karyotype analysis of the electric eel, Electrophorus electricus (Teleostei, Gymnotiformes), a strongly electric fish from northern South America, is presented. Two female specimens were analyzed, one from the Amazon River and one from the Araguaia River. The specimens had a chromosomal number of 2n = 52 (42M-SM + 10A). C-bands were present in a centromeric and pericentromeric position on part of the chromosomes; some interstitial C-bands were also present. Heteromorphic nucleolus organizer regions (NORs) were detected in two chromosome pairs of the specimen from the Amazon River. The chromosome number and karyotype characteristics are similar to those of other Gymnotidae species. The genera Electrophorus and Gymnotus are positioned as the basal lineages in the Gymnotiformes phylogeny.

Biologia molecular como ferramenta no esporte de alto rendimento: possibilidades e perspectivas

Várias estratégias têm sido pensadas com o propósito de se utilizar a biologia molecular como ferramenta na pré-seleção e na seleção de talentos esportivos, na manipulação genética visando ao aumento ou à diminuição da produção de determinadas substâncias pelo organismo, na prescrição do treinamento e na recuperação de lesões. Portanto, o objetivo desta revisão é apresentar o DNA como regulador do funcionamento do organismo e de que forma alterações no perfil genético, tanto espontâneas como induzidas artificialmente, podem modular respostas fisiológicas e morfológicas por alterar a expressão de determinadas proteínas. Será dada especial atenção à descrição dos procedimentos utilizados para a manipulação genética, nos baixos riscos associados e nas estratégias que têm sido desenvolvidas com o objetivo de detectá-la. Com base em conhecimentos científicos, coerência e bom senso, diversas visões devem ser expostas e amplamente discutidas para ser definido o que é permitido e o que é proibido nas competições esportivas.

Molecular markers and genetic diversity of Plasmodium vivax

Enhanced understanding of the transmission dynamics and population genetics for Plasmodium vivax is crucial in predicting the emergence and spread of novel parasite phenotypes with major public health implications, such as new relapsing patterns, drug resistance and increased virulence. Suitable molecular markers are required for these population genetic studies. Here, we focus on two groups of molecular markers that are commonly used to analyse natural populations of P. vivax. We use markers under selective pressure, for instance, antigen-coding polymorphic genes, and markers that are not under strong natural selection, such as most minisatellite and microsatellite loci. First, we review data obtained using genes encoding for P. vivax antigens: circumsporozoite protein, merozoite surface proteins 1 and 3α, apical membrane antigen 1 and Duffy binding antigen. We next address neutral or nearly neutral molecular markers, especially microsatellite loci, providing a complete list of markers that have already been used in P. vivax populations studies. We also analyse the microsatellite loci identified in the P. vivax genome project. Finally, we discuss some practical uses for P. vivax genotyping, for example, detecting multiple-clone infections and tracking the geographic origin of isolates.

A phylogenetic analysis of Brycon and Henochilus (Characiformes, Characidae, Bryconinae) based on the mitochondrial gene 16S rRNA

The genus Brycon, the largest subunit of the Bryconinae, has 42 valid species distributed from southern Mexico to the La Plata River in Argentina. Henochilus is a monotypic genus, comprising a single species (H. wheatlandii) found in the upper Rio Doce basin. In the present study, partial sequences of the mitochondrial gene 16S were obtained for fifteen species of Brycon and for Henochilus wheatlandii. The results showed that the genus Brycon is paraphyletic, since Henochilus is the sister-group of B. ferox and B. insignis. The most basal species analyzed were the trans-Andean species B. henni, B. petrosus, and B. chagrensis.

Enzyme kinetics, structural analysis and molecular modeling studies on a series of Schistosoma mansoni PNP inhibitors

The enzyme purine nucleoside phosphorylase from Schistosoma mansoni (SmPNP) is an attractive molecular target for the development of novel drugs against schistosomiasis, a neglected tropical disease that affects about 200 million people worldwide. In the present work, enzyme kinetic studies were carried out in order to determine the potency and mechanism of inhibition of a series of SmPNP inhibitors. In addition to the biochemical investigations, crystallographic and molecular modeling studies revealed important molecular features for binding affinity towards the target enzyme, leading to the development of structure-activity relationships (SAR).

Structural and chemical basis for anticancer activity of a series of 'beta'-tubulin ligands: molecular modeling and 3D QSAR studies

An important approach to cancer therapy is the design of small molecule modulators that interfere with microtubule dynamics through their specific binding to the ²-subunit of tubulin. In the present work, comparative molecular field analysis (CoMFA) studies were conducted on a series of discodermolide analogs with antimitotic properties. Significant correlation coefficients were obtained (CoMFA(i), q² =0.68, r²=0.94; CoMFA(ii), q² = 0.63, r²= 0.91), indicating the good internal and external consistency of the models generated using two independent structural alignment strategies. The models were externally validated employing a test set, and the predicted values were in good agreement with the experimental results. The final QSAR models and the 3D contour maps provided important insights into the chemical and structural basis involved in the molecular recognition process of this family of discodermolide analogs, and should be useful for the design of new specific ²-tubulin modulators with potent anticancer activity.

Synthesis and structural characterization of block and random low molecular weight copolymers composed of L-lactic acid and isosorbide succinate moieties

Isosorbide succinate moieties were incorporated into poly(L-lactide) (PLLA) backbone in order to obtain a new class of biodegradable polymer with enhanced properties. This paper describes the synthesis and characterization of four types of low molecular weight copolymers. Copolymer I was obtained from monomer mixtures of L-lactide, isosorbide, and succinic anhydride; II from oligo(L-lactide) (PLLA), isosorbide, and succinic anhydride; III from oligo(isosorbide succinate) (PIS) and L-lactide; and IV from transesterification reactions between PLLA and PIS. MALDI-TOFMS and 13C-NMR analyses gave evidence that co-oligomerization was successfully attained in all cases. The data suggested that the product I is a random co-oligomer and the products II-IV are block co-oligomers.

Comparative morphology among representatives of main taxa of Scaphopoda and basal protobranch Bivalvia (Mollusca)

This study deals with detailed morphology and anatomy of 4 species of Scaphopoda and 5 species of protobranch Bivalvia. Both classes are traditionally grouped in the taxon Diasoma, which has been questioned by different methodologies, such as molecular and developmental. This study is developed under a phylogenetic methodology with the main concern in performing it in an intelligible and testable methodology. The analyzed Scaphopoda species came from the Brazilian coast and belong to the family Dentaliidae [(1) Coccodentalium carduus; (2) Paradentalium disparile] and Gadiliidae; [(3) Polyschides noronhensis, n. sp. from Fernando de Noronha Archipelago; (4) Gadila braziliensis]. These species represent the main branches of the class Scaphopoda. From protobranch bivalves, representatives of the families Solemyidae [(5) Solemya occidentalis, from Florida; S. notialis, n. sp. from S.E. Brazil], Nuculanidae [(6) Propeleda carpentieri from Florida], and Nuculidae [(7) Ennucula puelcha, from south Brazil] are included. These species represent the main branches of the basal Bivalvia. The descriptions on the anatomy of S. occidentalis and of P. carpentieri are published elsewhere. The remaining are included here, for which a complete taxonomical treatment is performed. Beyond these species, representatives of other taxa are operationally included as part of the ingroup (indices are then shared with them), as a procedure to test the morphological monophyly of Diasoma. These taxa are: two lamellibranch bivalves [(8) Barbatia - Arcidae; (9) Serratina - Tellinidae; both published elsewhere;, and Propilidium (10) Patellogastropoda, and (11) Nautilus, basal Cephalopoda, based on basal taxa. The effective outgroups are (12) Neopilina (Monoplacophora) and (13) Hanleya (Polyplacophora). The phylogenetic analysis based on morphology revealed that the taxon Diasoma is supported by 14 synapomorphies, and is separated from Cyrtosoma (Gastropoda + Cephalopoda). Although they are not the main goal of this paper, the taxa Scaphopoda and Bivalvia are supported by 8 and by 7 synapomorphies respectively. The taxon Protobranchia resulted paraphyletic. Both scaphopod orders resulted monophyletic. The obtained cladogram is: ((((Coccodentalium carduus - Paradentalium disparile) (Polyschides noronhensis - Gadila brasiliensis)) ((Solemya occidentalis - S. notialis) (Propeleda carpenteri (Ennucula puelcha (Barbatia cancellaria - Serratina capsoides))))) (Propilidium curumim - Nautilus pompilius - Lolliguncula brevis)).

Occurrence and molecular characterization of Cryptosporidium spp. isolated from domestic animals in a rural area surrounding Atlantic dry forest fragments in Teodoro Sampaio municipality, State of São Paulo, Brazil

The aim of this study was to assess the occurrence of Cryptosporidium in domestic animals in rural properties surrounding rain forest fragments within the municipality of Teodoro Sampaio, southeastern Brazil. Conventional sucrose flotation method followed by molecular characterization of the parasites by sequencing PCR products amplified from SSU rRNA gene were used. Stool samples were collected from domestic animals raised as pets and livestock in all rural properties surrounding three forest fragments. Samples from cattle (197), equine (63), pigs (25), sheep (11), and dogs (28) were collected from 98 rural properties. The frequency of occurrence of Cryptosporidium within each animal species was 3.0% (6/197) among cattle and 10.7% (3/28) among dogs. Cryptosporidium was not detected in stool samples from equine, sheep, and pigs. All sequences obtained from the six samples of calves showed molecular identity with Cryptosporidium andersoni while all sequences from dog samples were similar to C. canis. The frequency of occurrence of Cryptosporidium in these domestic animal species was low. The absence of C. parvum in the present study suggests that the zoonotic cycle of cryptosporidiosis may not be relevant in the region studied. The presence of Cryptosporidium species seldom described in humans may be, otherwise, important for the wild fauna as these animals are a source of infection and dissemination of this protozoan to other animal species. The impact and magnitude of infection by C. andersoni in wild ruminants and C. canis in wild canids have to be assessed in future studies to better understand the actual importance of these species in this region.