Analyses of Sexual Reproductive Success in Transgenic and/or Mutant Plants

The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.     

Nuclear envelope barrier leak induced by dexamethasone

Nuclear pore complexes (NPCs) are multiprotein channels that span the nuclear envelope. They strongly limit the efficiency of gene transfection by restriction of nuclear delivery of exogenously applied therapeutic macromolecules. NPC dilation could significantly increase this efficiency. Recently, it was shown in oocytes of Xenopus laevis that NPCs dilate from about 82 to 110 nm within min after injection of the glucocorticoid analog dexamethasone (dex). In the present paper we analyzed by means of atomic force microscopy the structural details of NPC dilation and correlated them with functional changes in nuclear envelope permeability. 5-11 min after Dex injection NPC dilation was found at its maximum (approximately 140 nm). In addition, a yet unknown configuration, so-called giant pore, up to 300 nm in diameter, was visualized. Giant pore formation was paralleled by an increase in nuclear envelope permeability tested by electrophysiology and confocal fluorescence microscopy. Even large macromolecules lacking any nuclear localization signal (77 kDa FITC-dextran, molecule diameter up to 36 nm) could gain access to the nucleus. We conclude that dex transiently opens unspecific pathways for large macromolecules. Dex treatment could be potentially useful for improving the efficiency of nuclear gene transfection.     

Portal vein thrombosis and high factor VIII in Turner syndrome

BACKGROUNDS/AIMS: Turner syndrome is not usually associated with thrombotic events. The aim of this study is to report 3 Turner syndrome patients with portal vein thrombosis and, in 2 of them, high factor VIII. These findings are compared to values in Turner syndrome patients without thrombosis and controls. METHODS: In different years, 3 patients with Turner syndrome were initially seen at the Gastroenterology Clinic of Hospital de Clínicas de Porto Alegre, Brazil, for portal vein thrombosis. After the most common causes of portal vein thrombosis and thrombophilias had been excluded, the 2 surviving patients were studied for clotting factors VIII, IX and von Willebrand factor. The same factors were also assessed in 25 Turner syndrome patients without thrombosis and 25 normal girls. RESULTS: One of the patients with portal vein thrombosis died before the study. In the 2 surviving patients, factors VIII and von Willebrand levels were >150 IU/dl, which is considered to be high. In Turner syndrome patients without thrombosis, the mean factor VIII level was 127.2 +/- 41.1 IU/dl and for von Willebrand factor 101.2 +/- 26.9 IU/dl, while in control girls these were 116.0 +/- 27.6 and 94.28 +/- 27.5 IU/dl, respectively. Factor VIII and von Willebrand factor were not different between these 2 groups. When non-O blood group Turner syndrome patients and normal girls were compared, the former had significantly higher levels of factor VIII. CONCLUSIONS: This is the first report on the unusual finding of portal thrombosis in patients with Turner syndrome in whom high levels of factor VIII and von Willebrand factor were found. Factor VIII is higher in the non-O blood group Turner syndrome patients without thrombosis when compared to normal girls.     

An array of Escherichia coli clones over-expressing essential proteins: a new strategy of identifying cellular targets of potent antibacterial compounds

With the advancement of high throughput screening, it has become easier and faster to discover hit compounds that inhibit proliferation of bacterial cells. However, development in technologies used to identify cellular targets of potent antibacterial inhibitors has lagged behind. Here, we describe a novel strategy of target identification for antibacterial inhibitors using an array of Escherichia coli clones each over-expressing one essential protein. In a proof-of-concept study, eight essential genes were cloned into pLex5BA vector under the control of an inducible promoter. Over-expression of target proteins was confirmed. For two clones, one over-expressing FabI and the other over-expressing MurA enzymes, the host cells became 17- and 139-fold more resistant to the specific inhibitors triclosan and phosphomycin, respectively, while the susceptibility of other clones towards these inhibitors remained unchanged after induction of gene expression. Target identification via target protein over-expression was demonstrated using both mixed clone and individual clone assay formats.     

A new species ofLeptosphaerulina from decaying mangrove wood from Hong Kong

Leptosphaerulina mangrovei sp. nov. (Pleosporaceae, Ascomycota) from decaying mangrove wood ofKandelia candel from subtropical Hong Kong is described and compared to related taxa.     

Ω3-Polyunsaturated fatty acids prevent lipoperoxidation, modulate antioxidant enzymes, and reduce lipid content but do not alter glycogen metabolism in the livers of diabetic rats fed on a high fat thermolyzed diet

Ω3-Polyunsaturated fatty acids (Ω3-PUFAs) are known to act as hypolipidaemics, but the literature is unclear about the effects that Ω3-PUFAs have on oxidative stress in obese and diabetic patients. In this study, our aim was to investigate the effects of Ω3-PUFAs on oxidative stress, including antioxidant enzyme activity and hepatic lipid and glycogen metabolism in the livers of diabetic and non-diabetic rats fed on a high fat thermolyzed diet. Rats were divided into six groups: (1) the control group (C), (2) the control diabetic group (D), (3) the high fat thermolyzed diet group (HFTD), which were fed a diet that was enriched in fat that was heated for 60 min at 180°C, (4) the high fat thermolyzed diet diabetic group (D + HFTD), (5) the high fat thermolyzed diet + Ω3 polyunsaturated fatty acid group (HFTD + Ω3), and (6) the high fat thermolyzed diet + Ω3 polyunsaturated fatty acid diabetic group (D + HFTD + Ω3). The most important finding of this study was that Ω3-PUFAs are able to reduce triglycerides, non-esterified fatty acid, lipoperoxidation levels, advanced glycation end products, SOD/CAT enzymatic ratio, and CAT immunocontent and increase SOD2 levels in the livers of diabetic rats fed with a HFTD. However, Ω3-PUFAs did not alter the observed levels of protein damage, blood glucose, or glycogen metabolism in the liver. These findings suggest that Ω3-PUFAs may represent an important auxiliary adjuvant in combating some diseases like diabetes mellitus, insulin resistance, and non-alcoholic fatty liver disease.     

From thin to thick: major transitions during stem development

The variability of shoot architecture in plants is striking and one of the most extreme examples of adaptive growth in higher organisms. Mediated by the differential activity of apical and lateral meristems, flexibility in stem growth essentially contributes to this variability. In spite of this importance, the regulation of major events in stem development is largely unexplored. Recently, however, novel approaches exploiting knowledge from root and leaf development are starting to shed light on molecular mechanisms that regulate this essential plant organ. In this review, we summarize our understanding of initial patterning events in stems, discuss prerequisites for the initiation of lateral stem growth and highlight the burning questions in this context.     

Dexamethasone reduces bronchial wall remodeling during pulmonary migration of Strongyloides venezuelensis larvae in rats

Strongyloidiasis is an intestinal parasitosis with an obligatory pulmonary cycle. A Th2-type immune response is induced and amplifies the cellular response through the secretion of inflammatory mediators. Although this response has been described as being similar to asthma, airway remodeling during pulmonary migration of larvae has not yet been established. The aim of this study was to identify the occurrence of airway remodeling during Strongyloides venezuelensis (S. v.) infection and to determine the ability of dexamethasone treatment to interfere with the mechanisms involved in this process. Rats were inoculated with 9,000 S. v. larvae, treated with dexamethasone (2 mg/kg) and killed at 1, 3, 5, 7, 14 and 21 days. Morphological and morphometric analyzes with routine stains and immunohistochemistry were conducted, and some inflammatory mediators were evaluated using ELISA. Goblet cell hyperplasia and increased bronchiolar thickness, characterized by edema, neovascularization, inflammatory infiltrate, collagen deposition and enlargement of the smooth muscle cell layer were observed. VEGF, IL1-β and IL-4 levels were elevated throughout the course of the infection. The morphological findings and the immunomodulatory response to the infection were drastically reduced in dexamethasone-treated rats. The pulmonary migration of S. venezuelensis larvae produced a transitory, but significant amount of airway remodeling with a slight residual bronchiolar fibrosis. The exact mechanisms involved in this process require further study.