Digestibilidade in vivo dos nutrientes de cultivares de amoreira (Morus alba L.) em caprinos

Este trabalho foi conduzido para avaliar a digestibilidade in vivo dos nutrientes dos cultivares de amoreira FM 86 e FM SM nas idades de crescimento de 45 e 90 dias. Foram utilizados 8 caprinos machos, da raça Saanen, com 6 meses de idade e peso vivo médio de 26kg. O delineamento experimental adotado foi o inteiramente casualizado em esquema fatorial 2 X 2 (2 cultivares de amoreira e 2 idades de crescimento). O coeficiente de digestibilidade da FDN do cultivar FM 86 (74,82 %) superou o cultivar FM SM (69,36 %), não ocorrendo diferença significativa entre as idades de crescimento. Ocorreu interação significativa entre cultivar e idade de crescimento para o Coeficiente de Digestibilidade da FDA, e o cultivar FM 86 na idade de 45 dias (75,09 %) superou a de 90 dias (68,82 %). Para os parâmetros NDT e oeficientes de digestibilidade da energia, MS e PB, verificou-se superioridade da idade de corte de 45 dias, sem diferença entre os cultivares. Concluiu-se que os cultivares FM 86 e FM SM apresentaram excelente valor energético e altos coeficientes de digestibilidade da MS, da PB e dos constituintes da parede celular, indicando um elevado potencial da amoreira como forrageira para caprinos.

Poliaminas na embriogênese somática em cenoura (Daucus carota L.)

As poliaminas, putrescina (put), espermidina (spd) e espermina (spm) são amplamente distribuídas na natureza, desempenhando importante papel em vários eventos celulares. Considerando que as poliaminas estão envolvidas no processo embriogênico, torna-se importante conhecer as bases para estas alterações no metabolismo. O objetivo do presente trabalho foi observar os teores de poliaminas durante as diferentes fases da embriogênese somátka da cenoura. As análises foram realizadas, através da modificação do método de Flores e Galston a cada 96 horas durante 50 dias da cultura de células em suspensão. As células foram obtidas a partir de calos e inoculadas em meio de Murashige & Skoog (MS), modificado e acrescido de 0,2 mg/l de 2,4-D e 0,1 mg/l de cinetina durante os primeiros 14 dias da cultura, sendo que no restante do período permaneceram em meio MS desprovido de fiorreguladores. Os teores de poliaminas oscilaram durante todo o processo embriogênico, sendo que a putrescina foi a que apresentou maior acúmulo. Estes resultados sugerem que os níveis de espermidina e espermina são reduzidos em relação a putrescina devido a intensa utilização da spd e spm no processo de divisão e diferenciação celular, enquanto que a put parece ter apenas a função de sintetizar as outras duas amidas.

Microscopia eletrônica de varredura do endosperma de café (Coffea arabica L.) durante o processo de secagem

A manutenção da integridade das membranas celulares, entre outros eventos, é um forte indicativo de que a qualidade do café foi preservada na pós-colheita. Objetivou-se neste trabalho, analisar o efeito de diferentes métodos de secagem na manutenção da integridade da parede celular e da membrana plasmática de café natural e café despolpado, buscando determinar as condições e o momento em que ocorrem as rupturas microscópicas. Os cafés foram submetidos a um período de pré-secagem em terreiro. Após este, uma parcela de cada tipo de café foi desidratada no terreiro e, outra, à temperatura de 40ºC e 60ºC em secadores de camada fixa, monitorando-se a temperatura e o teor de água até 11% (bu). Nesse período, grãos foram aleatoriamente amostrados e fragmentos do endosperma preparados para a microscopia eletrônica de varredura, registrando-se diversas eletromicrografias, avaliando-se as alterações na membrana plasmática da célula do endosperma dos grãos de cafés em função do teor de água e tempo de secagem. O citoplasma das células a 11% (bu) de teor de água não foi comprometido na secagem em terreiro e a 40°C; na secagem a 60°C, observou-se comprometimento nas estruturas celulares nos cafés com teor de água de 20% (bu).

FLAVOR-CHANGING NEUTRAL CURRENTS IN SU(3)L-CIRCLE-TIMES-U(1)Y MODELS

We consider flavor changing neutral current effects coming from the Z' exchange in 3-3-1 models. We show that the mass of this extra neutral vector boson may be less than 2 TeV and discuss the problem of quark family discrimination.

Interaction of pathogenic fungi with host cells: Molecular and cellular approaches

This review provides an overview of several molecular and cellular approaches that are likely to supply insights into the host-fungus interaction. Fungi present intra- and/or extracellular host-parasite interfaces, the parasitism phenomenon being dependent on complementary surface molecules. The entry of the pathogen into the host cell is initiated by the fungus adhering to the cell surface, which generates an uptake signal that may induce its cytoplasmatic internalization. Furthermore, microbial pathogens use a variety of their surface molecules to bind to host extracellular matrix (ECM) components to establish an effective infection. on the other hand, integrins mediate the tight adhesion of cells to the ECM at sites referred to as focal adhesions and also play a role in cell signaling. The phosphorylation process is an important mechanism of cell signaling and regulation; it has been implicated recently in defense strategies against a variety of pathogens that alter host-signaling pathways in order to facilitate their invasion and survival within host cells. The study of signal transduction pathways in virulent fungi is especially important in view of their putative role in the regulation of pathogenicity. This review discusses fungal adherence, changes in cytoskeletal organization and signal transduction in relation to host-fungus interaction. (c) 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

Hepatocyte lesions and cellular immune response in yellow fever infection

The study of the in-situ cellular immune response is very important for the understanding of different liver infections. In the present study, 53 liver samples obtained by viscerotomy from patients who died during the course of jungle yellow fever were analyzed. The diagnosis was confirmed by serology, viral isolation and virus-specific immunohistochemistry. The specimens were analyzed by immunohistochemistry using specific antibodies for apoptosis, CD45RO, CD4, CD8, CD20, S100, CD57 and CD68. Quantitative analysis of the labeling pattern showed a clear predominance of the different phenotypes in the portal tract and midzone region of the acini. There was a predominance of T CD4+ lymphocytes, accompanied by the presence of T CD8+ lymphocytes, natural killer cells (CD57), macrophages and antigen-presenting cells (S100). The disproportion between the intensity of inflammation and the degree of hepatic injury was probably due to the intense apoptotic component, which classically does not induce an inflammatory response. The present study demonstrates that, despite the disproportion between injury and inflammation, the cellular immune response plays an important role in the pathogenesis of the hepatocytic injury observed in yellow fever, probably as a result of cytolytic actions through mechanisms involving MHC II and the activation of Fas receptors and granzymes/perforins. (C) 2006 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

DETECTION OF CELLULAR-IMMUNITY WITH THE SOLUBLE-ANTIGEN OF THE FUNGUS SPOROTHRIX-SCHENCKII IN THE SYSTEMIC FORM OF THE DISEASE

Sporothrix schenckii is the etiologic agent of sporotrichosis, a mycosis of world-wide distribution more commonly occurring in tropical regions. The immunological mechanisms involved in the prevention and control of sporotrichosis are not fully understood but apparently include both the humoral and cellular responses. In the present investigation, cellular immunity was evaluated by in vivo and in vitro tests in mice infected with yeast-like forms of S. schenckii. The disease developed systemically and cellular immunity was evaluated for a period of 10 weeks. The soluble antigen utilized in the tests was prepared from yeast form of the fungus through the sonication (20 min: 10 sonications at 50 W at 2-min intervals). Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen. This depression frequently indicates worsening of the disease, with greater involvement of the host. This is a promising field of research for a better understanding of the pathogeny of this mycosis.

HEAVY CHARGED LEPTONS IN AN SU(3)L-CIRCLE-TIMES-U(1)N MODEL

We consider an SU(3)L x U(1)N model for the electroweak interactions which includes extra charged leptons which do not mix with the known leptons. These new leptons couple to Z0 only through vector currents. We consider constraints on the mass of one of these leptons coming from the Z0 width and from the muon (g - 2) factor. The last one is less restrictive than the former.

Characterization of PLGA microparticles as a drug carrier for 3-ethoxycarbonyl-2H-benzofuro[3,2-f]-1-benzopyran-2-one. Ultrastructural study of cellular uptake and intracellular distribution

Here we describe the application of microparticles (MPs) for the delivery and release of the drug a benzopsoralen. We also evaluated the intracellular distribution and cellular uptake of the drug by using an encapsulation technique for therapeutic optimization. MPs containing the compound 3-ethoxycarbonyl-2H-benzofuro[3,2-f]-1-benzopyran-2-one (psoralen A) were prepared by the solvent evaporation technique, and parameters such as particle size, drug encapsulation efficiency, effect of the encapsulation process on the drug's photochemistry, zeta potential, external morphology, and < i > in vitro release behavior were evaluated. The intracellular distribution of MPs as well as their uptake by tissues were monitored. Size distribution studies using dynamic ligh scattering and scanning electron microscopy revealed that the MPs are spherical in shape with a diameter of 1.4 mu m. They present low tendency toward aggregation, as confirmed by their zeta potential (+10.6 mV). The loading efficiency obtained was 75%. As a consequence of the extremely low diffusivity of the drug in aqueous medium, the drug release profile of the MPs in saline phosphate buffer (pH 7.4) was much slower than that obtained in the biological environment. Among the population of peritoneal phagocytic cells, only macrophages were able to phagocytose poly-d,l-lactic-co-glycolic acid (PLGA) MP. The use of psoralen A in association with ultraviolet light (360 nm) revealed morphological characteristics of cell damage such as cytoplasmic vesiculation, mitochondria condensation, and swelling of both the granular endoplasmatic reticulum and the nuclear membrane. These results indicate that PLGA MP could be a promising delivery system for psoralen in connection with ultraviolet irradiation therapy (PUVA).

Cellular and tissue effects induced by photogemA (R) and red LED in photodynamic therapy

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

Interaction between the lateral preoptic area and the subfornical organ in the control of water ingestion caused by cellular dehydration, hypotension, hypovolemia, and deprivation

Water intake was studied in albino rats with lesions in the lateral preoptic area, in the subfornical organ, and in both the lateral preoptic area and the subfornical organ. Drinking was induced by cellular dehydration, hypovolemia, hypotension (isoproterenol or caval ligation), and water deprivation. The animals with lesions in both areas showed a significant reduction in their water intake in response to cellular dehydration. Drinking due to extracellular dehydration was reduced in the animals that received only subfornical organ lesions, and was reduced even further in the animals with both areas ablated. The lesions in the subfornical organ were sufficient to reduce the thirst induced by caval ligation. The lesions in both areas inhibit water intake induced by caval ligation. Water intake induced by deprivation was reduced when both areas were destroyed. These findings demonstrate that both the lateral preoptic area and the subfornical organ are necessary for normal drinking in response to cellular dehydration, hypovolemia, and hypotension. There is further evidence that the lateral preoptic area and subfornical organ interact in the control of water intake induced by a variety of thirst challenges.

Extra dimensions in superstring theory

It was earlier shown that an SO(9,1) θα spinor variable can be constructed from RNS matter and ghost fields. θα has a bosonic world-sheet super-partner λα which plays the role of a twistor variable, satisfying λΓμ λ = ∂xμ + iθΓμ ∂θ. For Type IIA superstrings, the left-moving [θL α, λL α] and right-moving [θRα, λRα] can be combined into 32-component SO(10,1) spinors [θA, λA]. This suggests that λAΓAB 11 λB = 2λL αλRα can be interpreted as momentum in the eleventh direction. Evidence for this interpretation comes from the zero-momentum vertex operators of the Type IIA superstring and from consideration of DD-branes. As in the work of Bars, one finds an SO(10,2) structure for the Type IIA superstring and an SO(9, 1) × SO(2, 1) structure for the Type IIB superstring. © 1997 Elsevier Science B.V.

Electrode poling of cellular polypropylene films with short high-voltage pulses

Recently, piezoelectric cellular polypropylene (PP) was proposed as a new type of quasi-ferroelectric. The observed hysteresis of the charge density as a function of the electric field could be explained as field-dependent charging inside the gas-filled voids. Interestingly enough, the measurable poling behavior of the macroscopic dipoles formed by charges that are trapped at the internal void surfaces is phenomenologically completely identical to the cooperative poling behavior of microscopic molecular dipoles in ferroelectric polymers. Therefore, it can be assumed that charge separation (or charge redistribution) and subsequent trapping in cellular PP is a rather fast switching process. In order to examine the poling dynamics, we developed an experimental setup for pulsed poling. High-voltage pulses with a duration of 45 μs (FWHM) were applied in direct contact to two-side metallized cellular PP films. The pulsed poling yields piezoelectricity in the cellular PP. We study and discuss the dependence of the resulting piezoelectricity on the poling field. We also characterize the charge separation during application of higher electric poling fields of up to -10 kV in direct contact to the two-side metallized films for longer times.