A differentiation-dependent splice variant of myosin light chain kinase, MLCK1, regulates epithelial tight junction permeability

Activation of Na(+)-nutrient cotransport leads to increased tight junction permeability in intestinal absorptive (villus) enterocytes. This regulation requires myosin II regulatory light chain (MLC) phosphorylation mediated by MLC kinase (MLCK). We examined the spatiotemporal segregation of MLCK isoform function and expression along the crypt-villus axis and found that long MLCK, which is expressed as two alternatively spliced isoforms, accounts for 97 +/- 4% of MLC kinase activity in interphase intestinal epithelial cells. Expression of the MLCK1 isoform is limited to well differentiated enterocytes, both in vitro and in vivo, and this expression correlates closely with development of Na(+)-nutrient cotransport-dependent tight junction regulation. Consistent with this role, MLCK1 is localized to the perijunctional actomyosin ring. Furthermore, specific knockdown of MLCK1 using siRNA reduced tight junction permeability in monolayers with active Na(+)-glucose cotransport, confirming a functional role for MLCK1. These results demonstrate unique physiologically relevant patterns of expression and subcellular localization for long MLCK isoforms and show that MLCK1 is the isoform responsible for tight junction regulation in absorptive enterocytes.     

Development and training of coordination skills in 11- to 19-year-old soccer players

The purpose of the study was to determine the specificity of the development and training of coordination skills (CSs) in 11- to 19-year-old soccer players (n = 600). Tests for soccer players’ CSs and technical skills and one- and two-year training experiments on targeted development of CSs were used. It was found that the period from 11 to 13 years of age was the most favorable for the development of CSs in soccer players, and the period from 14 to 16 years of age was the next most favorable. The use of special coordination training aimed at development of individual CSs led to a greater improvement, with the CS and technical skill parameters of athletes from the experimental groups being significantly higher (by 2.5–38.3 and 3.6–12.2%, respectively) than those of athletes from the control groups developing CSs by the traditional method using dexterity exercises.     

DESCRIPTION OF A NEW NAVICULOID DIATOM GENUS MORENEIS GEN. NOV. (BACILLARIOPHYCEAE) FROM SAND FLATS IN KOREA1

This article describes a new diatom genus Moreneis from the Yellow Sea sand flats on the west coast of Korea. The new genus is characterized by a unique combination of morphological characteristics, including the shape of the plastids, which have not been previously observed in diatoms. The valve morphology resembles other genera belonging to Lyrellaceae, within which we place this genus. In terms of areolae structure, Moreneis resembles Petroneis and Placoneis; however, it differs from both genera with respect to the raphe system and plastid shape. Cells of Moreneis spp. have a single large plastid appressed to the girdle of the secondary side of the valve, with two lobes extended toward the primary side of the valve. Furthermore, the unique feature of Moreneis frustules is the raphe, which has both external central and apical endings bent in opposite directions. We differentiated four taxa, which we describe as new for science. However, based on our findings, several established species from Navicula should also be formally transferred to Moreneis, including N. alpha Cleve, N. besarensis Giffen, N. epsilon Cleve, N. menaiana Hendey, N. polae Heiden, and N. quadri‐undulata F. Meister. Analysis of published data revealed that species belonging to Moreneis are numerous in tropical marine littoral waters, and in moderate climate zones, especially in the western Pacific, with only a few species occurring in the Mediterranean and Atlantic.     

Sangassou virus, the first hantavirus isolate from Africa, displays genetic and functional properties distinct from those of other murinae-associated hantaviruses

We have discovered the first indigenous African hantavirus, Sangassou virus (SANGV). The virus was isolated from an African wood mouse (Hylomyscus simus), trapped in a forest habitat in Guinea, West Africa. Here, we report on the characterization of the genetic and functional properties of the virus. The complete genome of SANGV was determined and showed typical hantavirus organization. The small (S), medium (M), and large (L) genome segments containing genes encoding nucleocapsid protein, two envelope glycoproteins, and viral polymerase were found to be 1,746, 3,650, and 6,531 nucleotides long, respectively. The exact 5' and 3' termini for all three segments of the SANGV genome were determined and were predicted to form the panhandle structures typical of bunyaviruses. Phylogenetic analyses of all three segment sequences confirmed SANGV as a Murinae-associated hantavirus most closely related to the European Dobrava-Belgrade virus. We showed, however, that SANGV uses β(1) integrin rather than β(3) integrin and decay-accelerating factor (DAF)/CD55 as an entry receptor. In addition, we demonstrated a strong induction of type III lambda interferon (IFN-λ) expression in type I IFN-deficient Vero E6 cells by SANGV. These properties are unique within Murinae-associated hantaviruses and make the virus useful in comparative studies focusing on hantavirus pathogenesis.     

Cytometric evaluation of transferrin receptor 1 (CD71) in childhood acute lymphoblastic leukemia

Transferrin receptor 1 (CD71) is a transmembrane glycoprotein responsible for cellular iron uptake. Higher expression of CD71 has been identified as a negative prognostic marker for numerous solid tumor types and for some lymphomas. The aim of this study was to evaluate CD71 expression on acute lymphoblastic leukemia (ALL) cells and to follow its possible clinical correlations. Sixty one patients, aged 1-17 years and diagnosed with ALL, were enrolled in the study. CD71 expression was analyzed on the bone marrow blastic cells by flow cytometry. CD71 expression on the leukemic blasts was diversified; in most patients, all blastic cells showed expression of CD71, but levels of expression varied. CD71 expression was statistically higher on T-lineage leukemias. Within the B lineage ALL, a significant difference in CD71 expression existed between precursor B ALL and mature B-ALL, which showed higher CD71 expression. CD71 expression positively correlated with Hgb concentration at diagnosis. Initial risk group assessment and therapy response were not correlated with CD71 expression, although disease free and overall survival times tended to be shorter in patients with B-lineage leukemias with initial high CD71 expression.     

Beta-amyloid peptides enhance the proliferative response of activated CD4CD28 lymphocytes from Alzheimer disease patients and from healthy elderly

Alzheimer's disease (AD) is the most frequent form of dementia among elderly. Despite the vast amount of literature on non-specific immune mechanisms in AD there is still little information about the potential antigen-specific immune response in this pathology. It is known that early stages of AD include β-amyloid (Aβ)- reactive antibodies production and inflammatory response. Despite some evidence gathered proving cellular immune response background in AD pathology, the specific reactions of CD4(+) and CD8(+) cells remain unknown as the previous investigations yielded conflicting results. Here we investigated the CD4(+)CD28(+) population of human peripheral blood T cells and showed that soluble β-amyloids alone were unable to stimulate these cells to proliferate significantly, resulting only in minor, probably antigen-specific, proliferative response. On the other hand, the exposure of in vitro pre-stimulated lymphocytes to soluble Aβ peptides significantly enhanced the proliferative response of these cells which had also lead to increased levels of TNF, IL-10 and IL-6. We also proved that Aβ peptide-enhanced proliferative response of CD4(+)CD28(+) cells is autonomous and independent from disease status while being associated with the initial, ex vivo activation status of the CD4(+) cells. In conclusion, we suggest that the effect of Aβ peptides on the immune system of AD patients does not depend on the specific reactivity to Aβ epitope(s), but is rather a consequence of an unspecific modulation of the cell cycle dynamics and cytokine production by T cells, occurring simultaneously in a huge proportion of Aβ peptide-exposed T lymphocytes and affecting the immune system performance.     

Implication of Glutathione in the In Vitro Antiplasmodial Mechanism of Action of Ellagic Acid

The search for new antimalarial chemotherapy has become increasingly urgent due to parasite resistance to current drugs. Ellagic acid (EA) is a polyphenol, recently found in various plant products, that has effective antimalarial activity in vitro and in vivo without toxicity. To further understand the antimalarial mechanism of action of EA in vitro, we evaluated the effects of EA, ascorbic acid and N-acetyl-L-cysteine (NAC), alone and/or in combination on the production of reactive oxygen species (ROS) during the trophozoite and schizonte stages of the erythrocytic cycle of P. falciparum. The parasitized erythrocytes were pre-labelled with DCFDA (dichlorofluorescein diacetate). We showed that NAC had no effect on ROS production, contrary to ascorbic acid and EA, which considerably reduced ROS production. Surprisingly, EA reduced the production of the ROS with concentrations (6.6×10⁻⁹ − 6.6×10⁻⁶ M) ten-fold lower than ascorbic acid (113×10⁻⁶ M). Additionally, the in vitro drug sensitivity of EA with antioxidants showed that antiplasmodial activity is independent of the ROS production inside parasites, which was confirmed by the additive activity of EA and desferrioxamine. Finally, EA could act by reducing the glutathione content inside the Plasmodium parasite. This was consolidated by the decrease in the antiplasmodial efficacy of EA in the murine model Plasmodium yoelii- high GSH strain, known for its high glutathione content. Given its low toxicity and now known mechanism of action, EA appears as a promising antiplasmodial compound.     

Density and potential utilisation of medicinal grassland plants from Abe Bailey Nature Reserve, South Africa

The Abe Bailey Nature Reserve, South Africa has been identified as a potential community resource reserve compatible with biodiversity conservation. As part of the planning and public participation phase this study investigated the potential for sustainably harvesting medicinal plants. Medicinal plant use data on local species, parts used and harvesting techniques, in collaboration with neighbouring traditional healers were collected. A census of these plants was conducted in the reserve and frequency, density and abundance were calculated. A medicinal plant rating system for assessing conservation priorities was used to combine both social-qualitative and ecological-quantitative data. Five medicinal species suitable for high impact harvesting were identified. Thirty-four species have potential to be set up as harvesting trials to determine sustainable quotas. Thirty-one medicinal species including Boophane disticha, Dicoma anomala, Eucomis autumnalis, Hypoxis hemerocallidea, Pentanisia prunelloides and Indigofera daleoides are considered to be site-specific sensitive species and should not be harvested from the reserve. Following this research an on site nursery has been started at the reserve. A multi-pronged approach involving harvesting trials, propagation and plant rescue from developments to cope with escalating demand and dwindling natural populations needs to be implemented.