OSP/claudin-11 forms a complex with a novel member of the tetraspanin super family and beta1 integrin and regulates proliferation and migration of oligodendrocytes

Oligodendrocyte-specific protein (OSP)/claudin-11 is a major component of central nervous system myelin and forms tight junctions (TJs) within myelin sheaths. TJs are essential for forming a paracellular barrier and have been implicated in the regulation of growth and differentiation via signal transduction pathways. We have identified an OSP/claudin-11-associated protein (OAP)1, using a yeast two-hybrid screen. OAP-1 is a novel member of the tetraspanin superfamily, and it is widely expressed in several cell types, including oligodendrocytes. OAP-1, OSP/claudin-11, and beta1 integrin form a complex as indicated by coimmunoprecipitation and confocal immunocytochemistry. Overexpression of OSP/claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line. Anti-OAP-1, anti-OSP/claudin-11, and anti-beta1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/claudin-11-deficient primary oligodendrocytes. These data suggest a role for OSP/claudin-11, OAP-1, and beta1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.     

Two common nonsynonymous paraoxonase 1 (<Emphasis Type="Italic">PON1</Emphasis>) gene polymorphisms and brain astrocytoma and meningioma

Background  

Human serum paraoxonase 1 (PON1) plays a major role in the metabolism of several organophosphorus compounds. The enzyme is encoded by the polymorphic gene PON1, located on chromosome 7q21.3. Aiming to identify genetic variations related to the risk of developing brain tumors, we investigated the putative association between common nonsynonymous PON1 polymorphisms and the risk of developing astrocytoma and meningioma.     

Long-term effects of graduated compression stockings on cardiorespiratory performance

The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners.     

The action of serotonin and its analogs on the in vitro maturation of amphibian oocytes

Indolylalkylamines (5-HT, 5-chlorotryptamine, 5-ethyltryptamine) suppress or block the progesterone-induced oocyte maturation in Bufo viridis and Xenopus laevis and disturb cytoskeletal rearrangements associated with oocytes involved, together with the other transmitter systems, in modulation of progesterone effect.     

Gangliosides of sea urchin embryos. Their localization and participation in early development

The influence of antibodies to gangliosides of sea urchin Strongylocentrotus intermedius eggs on early embryos of this species was studied. gamma-Globulins were isolated from rabbit anti-ganglioside serum by micropreparative electrophoresis. These gamma-globulins produced anomalies in the development of embryos permeabilized in Triton X-100. The anomalies were not observed when anti-ganglioside gamma-globulins were added to the incubation medium together with gangliosides or when the permeabilized embryos were incubated with gamma-globulins of normal rabbit serum. Pretreatment of S. intermedius embryos with serotonin, tryptamine or some other indole derivatives led to the disappearance of ganglioside determinants from the cell surface and sharply increased immunofluorescence within the cell. Such pretreatment of embryos increased the amount of cell-associated gangliosides more than threefold as compared to untreated embryos. Serotonin was shown to bind specifically to sea urchin gangliosides immobilized on octyl-Sepharose. These observations suggest that cell-surface gangliosides, after binding drugs, are internalized and that serotonin and its antagonists inhibit the transport of newly synthesized gangliosides to the cell-surface membrane.     

About possible functional interaction between serotonin and neuropeptides in control processes of embryogenesis (Experiments on embryos ofTritonia diomedea)

Ritanserin and inmecarb hydrochloride, antagonists of serotonin, act cytostatically and teratogenically on early embryos ofTritonia diomedea, a nudibranch mollusk. On the basis of a pharmacological analysis and the type of developmental abnormalities observed, this action appears to be due to disturbances in the functional activity of endogenous serotonin and is associated with damage to the cytoskeleton. The effects of ritanserin and inmecarb are prevented or attenuated by lipophilic serotonin analogs (serotoninamides of polyenoic fatty acids), as well as by polypeptides isolated from neurons Pd5 and Pd6 of the pedal ganglia of the adultTritonia. In late embryos (stage of veligers), serotonin and to a lesser extent its lipophilic analogs strongly increase embryonic motility. This effect of serotonin is potentiated by some neuropeptides and inhibited by others. These results provide evidence for functional interaction between serotonin and neuropeptides in the control processes of embryogenesis.     

Variability in host plant resistance of Sorghum to Striga Hermonthica infestation in West Africa

Fourteen elite sorghum lines were evaluated for their resistance to Striga hermonthica at three locations in Nigeria and Mali. Results showed that many of the lines especially MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64 (Keninkédié) and the check SRN 39 remained resistant to Striga in all locations with low emerged Striga counts, while SAMSORG 14 had the highest Striga infestation in all locations. Considerable variation in reaction to Striga infestation was observed on Séguètana, 97-SB-F5DT-63 (Wasa), 97-SB-F5DT-65, CMDT 38, CMDT 39 and CMDT 45 which were susceptible to Striga at Samaru, Nigeria but were resistant to Striga at both locations in Mali. Based on low Striga resistance and high grain yield, lines MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64, 97-SB-F5DT-65, CMDT 39 and SAMSORT 14 have been nominated for wider evaluation across more West African countries.     

Patterns in the binding of cytotoxic neuropharmacologic preparations by early sea urchin embryos]

Early embryos of Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis intensively bind cytotoxic neuropharmacological drugs, such as antiserotonine indole derivatives, cholinolytics and tricyclic antidepressants. The binding intensity decreases markedly upon quaternization of the drugs. Quantitative analysis indicates that: a)with respect to the drugs, the suspension of living embryos may be described as a single adsorbing system following the Langmuir equation; b) at least two independent binding pools exist in embryos; c) the magnitude of cytotoxic effect of a given drug is not proportional to its binding.     

Sensitivity of sea urchin early embryos to antagonists of acetylcholine and monoamines

Early embryos of A. lixula are 10–800 times more sensitive to several neuropharmaca than are early embryos of 6 other studied species of sea urchins. Of 53 neuropharmaca studied, 25 were found hyperactive; of 19 other inhibitors of development (mitotic and metabolic poisons) only antimycin A was hyperactive for A. lixula. Both hyperactive neuropharmaca and neuropharmaca with normal activity suppress cleavage divisions and inhibit protein biosynthesis acting as antagonists of intracellular acetylcholine and monoamines. The mechanism responsible for the normal sensitivity and hypersensitivity of early sea urchin embryos is discussed.     

The influence of second messengers and related substances on the sensitivity of early embryos to cytostatic neurochemicals

"Prenervous" neurotransmitters interact with second messengers in the regulation of early embryogenesis of sea urchins and the clawed frog Xenopus laevis. Propranolol and atropine inhibit cleavage divisions of X. laevis only after their intracellular administration. The level of the membrane potential (including a zero level) of the embryos studied is not essential for the cleavage divisions. Possible mechanisms of action of the "prenervous" neurotransmitters at the intracellular level and their coupling with second messengers are discussed.