1,448 research outputs found
Leaf Beetles of the Cayman Islands (Coleoptera: Chrysomelidae)
Data are presented for 29 chrysomelid species (Coleoptera: Chrysomelidae) occurring in the Cayman Islands, West Indies, 26 of these not having been reported from these islands previously. Altica occidentalis Suffrian is removed from the genus Lysathia Bechyné and reinstated in Altica Geoffroy. Chaetocnema perplexa Blake is synonymized with Chaetocnema confinis Crotch, new synonymy. Omophoita cyanipennis octomaculata (Crotch) is synonymized with Omophoita cyanipennis (Fabricius), new synonymy. The following nine species are named and described: Apraea luciae, Apraea priscilae, Cryptocephalus catharinae, Cryptocephalus kirki, Cryptocephalus paulotigrinus, Longitarsus alisonae, Megistops adiae, Nyctiplanctus bifasciatus, Syphrea thurstonae, all are new species. Taxonomic notes and a key to species, as well as information on plant associations and extralimital distribution, are also provided
Evolução da produção de leite em pequenos ruminantes: polimorfismos do gene da hormona de crescimento
Os efetivos autóctones de pequenos ruminantes têm vindo a diminuir,em parte devido ao seu baixo potencial produtivo. A necessidade de encontrar formas mais expeditas de aumentar o potencial produtivo
das nossas raças, e assim promover a sua manutenção bem como a sustentabilidade
dos sistemas extensivos onde são explorados, levou à procura de marcadores moleculares, nomeadamente no gene da hormona de crescimento (GH), associados com a produção e qualidade do leite em pequenos ruminantes. Nas raças ovinas Churra da Terra Quente,
Merino da Beira Baixa, Saloia e Serra da Estrela e caprinas Algarvia e Serrana verificou -se que o gene da GH é muito polimórfico, tendo sido encontrados polimorfismos especÃficos em algumas das raças. Os resultados sugerem que os polimorfismos do gene da GH, entre outros (e.g., nas caseÃnas), poderão vir a ser utilizados na seleção assistida por marcadores genéticos, de modo a melhorar da produção de leite sem afetar a sua qualidade. Contudo, a resposta à seleção será sempre condicionada pela prática de um correto maneio alimentar dos animais
Functional analysis of the mouse Nodal antagonist, Cerl2, during left-right axis formation
Although recently our understanding of how the LR asymmetry is generated in vertebrate embryos has seen rapid progress, many important questions remain to be explained. In mouse embryos, the leftward flow of the extra-embryonic fluid in the node cavity, called nodal flow, seems to be the symmetry-breaking event. However, it is not yet know how this flow functions or how the asymmetric signal(s) generated in the node is/are transferred to the lateral plate mesoderm. The mouse gene cerberus-like2(cerl2) encodes a 20-kDa protein with a predicted signal peptide sequence and a cysteine-rich domain (CRD) containing nine cysteines characteristic of the Cerberus/DAN family. Whole-mount in situ hybridization studies showed that cerl2 transcripts could be first detected in a horseshoe-shaped expression pattern in the perinodal region of the mouse embryo (E7.0), resembling Nodal expression at this stage. At stage E7.5, expression of cerl2 begins to decrease in intensity on the left side, and by early somitogenesis (E8.0), it can be strongly detected in the right side of the node, assuming a complementary expression pattern to that observed in Nodal. Furthermore, it was shown that Cerl2 activity is upstream of the Nodal receptor inhibiting Nodal and its downstream targets. A physical interaction between these two proteins exists, which suggests that Cerl2 is a secreted Nodal antagonist. Here, to elucidate the role of Cerl2 protein in the early events of symmetry breaking the functional activity of this Nodal antagonist will be discussed.info:eu-repo/semantics/publishedVersio
Myxobolus sp. and Henneguya sp. (Cnidaria: Myxobolidae) natural co-infection in the kidney of Piaractus mesopotamicus(Characiformes: Serrasalmidae)
This study evaluated the myxozoan infection and
histopathology of the kidney of freshwater fish Piaractus
mesopotamicus from intensive fish farming in Brazil. A total
of 55 fish were examined for myxozoan infection. Infected
organs were processed by usual histology and stained with
hematoxylin-eosin (H&E) and Ziehl-Neelsen (ZN). From the
total of 55 fish analyzed, 47 (85.45%) presented myxospores,
being 9.09% (5/55) only with Myxobolus sp., 5.45% (3/55)
only with Henneguya sp., and 70.91% (39/55) presenting both
parasites. The presence of myxospores was associated with
histological alterations in both stromal and renal parenchyma.
Myxospores were found mostly in the peritubular interstitial
tissue and in low intensity in the glomerulus which caused
nuclear hypertrophy and loss of Bowman space. An increase
in the glomerular tuft and a reduction in the lumen of the
collector tubules were also observed, besides the high number
of melanomacrophage cells in the glomerulus. This study reports
for the first time detection of myxozoan mixed infection
in one organ of pacu and discuss the possible transportation of
myxospores in the circulating blood
Yarrowia lipolytica : an industrial workhorse
Yarrowia lipolytica is one of the most extensively studied ‘‘non-conventional’’ yeasts, being a strictly aerobic microorganism capable of producing important metabolites and having an intense secretory activity, which justifies efforts to use it in industry (as a biocatalyst), in molecular biology and in genetics studies. Moreover, Y. lipolytica has been considered an adequate model for dimorphism studies in yeasts. Yarrowia lipolytica presents the ability to grow on Olive Mill Wastewater (OMW) as well as to degradate organic compounds, including aliphatic and aromatic hydrocarbons, often
accompanied by biosurfactants production. One of the most important products secreted by this microorganism is lipase which can be exploited for several applications in the detergent, food, pharmaceutical, and environmental industries. In addition, Y. lipolytica is able to produce citric acid and aroma from a variety of carbon sources, including sugars, alkanes, plant oils, starch hydrolysates, ethanol, and glycerol. Thus, this chapter presents an overview of Yarrowia lipolytica features and its major biotechnological applications
Recurrent Upper Gastro-Intestinal Bleed Caused by a Pseudo-Aneurysm of the Gastro-Duodenal Artery
Os autores apresentam o caso clÃnico de um homem de 39 anos de idade com antecedentes de pancreatite crónica, que apresenta um quadro de hemorragia digestiva alta recorrente, com repercussão hemodinâmica, endoscopias altas sucessivas sem alterações, e cujos exames imagiológicos revelam presença
de mal-formação vascular do tronco celÃaco. Na sequência de mais um episódio de hemorragia digestiva alta com franca repercussão hemodinâmica, é internado no Serviço de Medicina,realizando arteriografia selectiva que mostrou a presença de pseudo-aneurisma da artéria gastroduodenal. Após a embolização, verificou-se uma progressiva e mantida melhoria da sua situação clÃnica. Descrevem os autores um quadro de hemorragia
digestiva alta recorrente por malformação arterial associada à pancreatite crónica
Analysis of the effects of hyperbaric gases on S. cerevisiae cell cycle through a morphological approach
The effects of hyperbaric gases on the cell cycle of Saccharomyces cerevisiae were studied in batch cultures under pressures between 0.1 and 0.6 MPa and different gas compositions (air, oxygen, nitrogen or carbon dioxide). Classification of S. cerevisiae cells based on their morphology stages was obtained using an automatic image analysis procedure. Information on the distribution of different sub-populations along the cell cycle
is reported. A structured morphological model was developed and used to describe the measured data. The results herein reported demonstrate that the bud separation phase is the limiting step in cell duplication. Additionally, the influence of the environmental conditions, specially the oxygen partial pressure, on the START event is reported. Under anaerobic conditions, no significant influence of hyperbaric gases on the cell cycle was
verified.CAPES/GRICES, CNPq (Brazil)
Fundação para a Ciência e a Tecnologia (FCT
Saccharomyces cerevisiae morphology under hyperbaric gases
The effects of hyperbaric stress on the morphology of Saccharomyces cerevisiae were studied
in batch cultures under pressures between 0.1 MPa and 0.6 MPa and different gas
compositions (air, O2, N2, or CO2), covering aerobic and anaerobic conditions. A method
using automatic image analysis for cell classification based on their morphology was applied to experimental data. Cell viability was assessed through the Methylene Blue staining method and the percentages of viable and non-viable cells were also estimated using digital image processing.
The results show that the effect of pressure on cell activity strongly depends on the nature of the gas used for pressurization. While nitrogen and air to a maximum of 0.6 MPa of pressure were innocuous to yeast, oxygen and carbon dioxide pressure caused cell inactivation, which was confirmed by the reduction on the number of budding cells with time and also a decrease in the average cell size (0.6 MPa CO2). A model taking into account cell
viability reveals the opposing effects between oxygen availability and the baric and oxidative
stresses present on the system. It is shown that cell viability in general is not constant during
the experiments but strongly depends on the environment
Classification of Saccharomyces cerevisiae morphology employing image analysis
Population dynamics of microbial systems can be described by several approaches and in
various levels of complexity, each of them arising from specific goals and limitations. From
the process-engineering viewpoint there is a need for a comprehensive mathematical model
describing population dynamics in terms of measurable entities (microbes) and chemicals
involved (limiting substrate, dissolved oxygen, etc.), as well as process configuration (number
and type of reactors, interconnections, etc.) and process parameters (inlet flow rate and
composition, reactor holdup, and more) [1].
The description of intricate population dynamics and the inference of cell states lead to
complex models with a great number of parameters. Knowledge about whole cell cycle and
morphology classification is imperative, since a considerable difference exists between the
cell description employed in model formulation and the laboratory reality. As soon as in
biological systems exists a relationship between cell morphology and productivity, some
authors drive efforts towards the on-line measurement of biomass component to avoid
process delays [2],[4] or to determine cellular characteristics related to its morphology and/or
physiology through image processing analysis [5],[6],[7].
Saccharomyces cerevisiae size and shape distribution are affected by growth rate, mutation,
and environmental conditions (composition, temperature, pressure, presence of oxidant
agents, etc.). Although its shape usually assumes an ellipsoid contour it is modified along the
cell cycle by bud formation and growing attached to the mother [5].
This work deals with S. cerevisiae classification based on morphology analysis. Image
acquisition was conducted in an optical microscope (x 400 magnification) coupled with a
black and white camera and linked to a microcomputer by a frame grabber. Traditional tools
generally used for image enhancing were employed. Feature extraction and objects separation
were necessary to classify "mothers" and "daughters" and to determine its frequency in the
analyzed samples.
Cells were automatically divided in five different classes with respect to bud size compared to
the respective mother through image analysis employing Matlab (v.6.1, The Mathworks Inc.).
This methodology was validated with distinct samples and employed along Sacharomyces
cerevisiae growth in different operational conditions. The data herein obtained is being used
for morphological structured model formulation.Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq); CAPES
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