Molecular taxonomy of Dunaliella (Chlorophyceae), with a special focus on D. salina: ITS2 sequences revisited with an extensive geographical sampling

We used an ITS2 primary and secondary structure and Compensatory Base Changes (CBCs) analyses on new French and Spanish Dunallela salina strains to investigate their phylogenetic position and taxonomic status within the genus Dunaliella. Our analyses show a great diversity within D. salina (with only some clades not statistically supported) and reveal considerable genetic diversity and structure within Dunaliella, although the CBC analysis did not bolster the existence of different biological groups within this taxon. The ITS2 sequences of the new Spanish and French D. salina strains were very similar except for two of them: ITC5105 "Janubio" from Spain and ITC5119 from France. Although the Spanish one had a unique ITS2 sequence profile and the phylogenetic tree indicates that this strain can represent a new species, this hypothesis was not confirmed by CBCs, and clarification of its taxonomic status requires further investigation with new data. Overall, the use of CBCs to define species boundaries within Dunaliella was not conclusive in some cases, and the ITS2 region does not contain a geographical signal overall.     

GABAA receptor subtype involvement in addictive behaviour

GABA_A receptors form the major class of inhibitory neurotransmitter receptors in the mammalian brain. This review sets out to summarize the evidence that variations in genes encoding GABA_A receptor isoforms are associated with aspects of addictive behaviour in humans, while animal models of addictive behaviour also implicate certain subtypes of GABA_A receptor. In addition to outlining the evidence for the involvement of specific subtypes in addiction, we summarize the particular contributions of these isoforms in control over the functioning of brain circuits, especially the mesolimbic system, and make a first attempt to bring together evidence from several fields to understanding potential involvement of GABA_A receptor subtypes in addictive behaviour. While the weight of the published literature is on alcohol dependency, the underlying principles outlined are relevant across a number of different aspects of addictive behaviour.     

Characterization of glycoside residues of porcine zona pellucida and ooplasm during follicular development and atresia

The glycoside residues (glycoconjugates, GC) of the zona pellucida (ZP) glycoproteins are important during the first phases of fecundation. Our aim in this work was to determine the lectin affinity pattern of porcine ZP in order to analyze the changes that take place during: (a) preantral folliculogenesis, (b) the follicular atresia process, and (c) antral growth. Several prepubertal and adult pig ovaries and different sized antral follicles were used. Conventional carbohydrate histochemical techniques and peroxidase and digoxigenin (DIG) lectins were used to reveal the acid groups and the glycosidic residues of the ZP. It was seen that the ZP forms in the preantral follicles throughout their growth period. In primordial and primary follicles, ZP in the process of formation showed neutral GC. SBA, RCA-I, MAA, WGA lectins, and AAA after methylation-saponification (MS) were positive in the ZP of primordial and primary follicles. The affinity for SBA, RCA-I, MAA, and WGA increased in the multilaminar-primary follicles and new affinities for UEA-I and LFA were observed. After MS, AAA, SNA, PNA, and SBA reactivity was observed. The ZP of antral follicle oocytes of different sizes showed the same lectin pattern as multilaminar-primary follicles. The oocyte ooplasm and the follicular fluid of large antral follicles showed less affinity for WGA and LFA lectins and less intensive staining with AB (pH 2.5). Atresia did not change the antral or preantral follicle oocyte ZP lectin pattern. In conclusion, the follicles showed substantial changes in their ZP glycosidic composition as they developed, especially, during the change from primary to multilaminar-primary follicles. The ZP glycosidic composition showed no significant change during the growth of antral follicles and follicular atresia in our study.     

Regulation of steroidogenesis by atrial natriuretic peptide (ANP) in the rat testis: differential involvement of GC-A and C receptors

Previous studies have established a stimulatory effect of natriuretic peptides (NP) on testosterone production in mouse Leydig cells as intense as that of LH. Chronic administration of ANP in mice, on the other side, reduced testosterone levels. So, the understanding of the role of ANP on testicular steroidogenesis has been impaired by discrepant findings. The aim of the present study was to clarify the physiological role of ANP in the rat testis steroidogenesis using a model that preserves the interactions between testis cells and a medium devoid of any circulating factors that could interfere with testosterone production. First, ANP was immunolocalized in the interstitial compartment of the rat testis, mainly in Leydig cells. We also determined the presence of ANP and both GC-A (guanylyl cyclase A) and C receptors by real-time PCR in testis. Perfusion in vitro of testis with ANP (1 and 3x10(-7)M) stimulated testosterone production in a time- and dose-dependent manner. On the other side, testosterone secretion induced by LH was blunted by ANP. Similar effect was obtained using the specific C receptor ligand, cANF, indicating the involvement of C receptor in such response. In conclusion, ANP stimulated testosterone production in the rat testis perfused in vitro but decreased testosterone production LH-induced, effect that seems to involve C receptor. To this extent, our results suggest the existence of a local and complex peptidergic system in the rat testis, involving ANP and its receptors that could importantly modulate the androgen biosynthesis.     

New insights into the pathogenesis of vitiligo: imbalance of epidermal cytokines at sites of lesions

Vitiligo is a skin disease that is caused by selective destruction of melanocytes and is characterized by white spots. Melanocytes and keratinocytes seem to exhibit a functional close relationship, mediated at least in part by keratinocyte-derived cytokines, which seem important for survival and activity of melanocytic cells. We wanted to investigate the hypothesis that in vitiligo the expression of epidermal cytokines may be modified compared with normal skin. In 15 patients with active, non-segmental vitiligo, biopsies were obtained from lesional, perilesional and non-lesional skin; normal skin from five healthy donors was also tested. Tissue sections were tested using immunohistochemistry for the expression of keratinocyte-derived cytokines with stimulating activity, such as granulocyte-monocyte colony stimulating factor (GM-CSF), basic fibroblastic growth factor (bFGF), and stem cell factor (SCF) or with inhibiting activity, such as interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) on melanocytes. Cytokine receptors and specific melanocytic markers were also investigated. No melanocyte was identified in lesional skin by means of specific markers or c-kit receptor, whereas in perilesional, non-lesional and healthy skin, melanocytes were found in similar number. In vitiligo skin a significantly lower expression of GM-CSF, bFGF and SCF was found, and a significantly higher expression of IL-6 and TNF-alpha was detected, compared with perilesional, non-lesional and healthy skin. In conclusion, we provided evidence that a significant change of epidermal cytokines exists in vitiligo skin compared with perilesional, non-lesional and healthy skin, suggesting that the cytokine production of epidermal microenvironment may be involved in vitiligo.     

Copolymer-1 induces adaptive immune anti-inflammatory glial and neuroprotective responses in a murine model of HIV-1 encephalitis

Copolymer-1 (COP-1) elicits neuroprotective activities in a wide range of neurodegenerative disorders. This occurs, in part, by adaptive immune-mediated suppression of microglial inflammatory responses. Because HIV infection and immune activation of perivascular macrophages and microglia drive a metabolic encephalopathy, we reasoned that COP-1 could be developed as an adjunctive therapy for disease. To test this, we developed a novel animal model system that reflects HIV-1 encephalitis in rodents with both innate and adaptive arms of the immune system. Bone marrow-derived macrophages were infected with HIV-1/vesicular stomatitis-pseudotyped virus and stereotactically injected into the basal ganglia of syngeneic mice. HIV-1 pseudotyped with vesicular stomatitis virus envelope-infected bone marrow-derived macrophages induced significant neuroinflammation, including astrogliosis and microglial activation with subsequent neuronal damage. Importantly, COP-1 immunization reduced astro- and microgliosis while diminishing neurodegeneration. Hippocampal neurogenesis was, in part, restored. This paralleled reductions in proinflammatory cytokines, including TNF-alpha and IL-1beta, and inducible NO synthase, and increases in brain-derived neurotrophic factor. Ingress of Foxp3- and IL-4-expressing lymphocytes into brains of COP-1-immunized animals was observed. We conclude that COP-1 may warrant therapeutic consideration for HIV-1-associated cognitive impairments.     

Potential anthropogenic regime shifts in three freshwater lakes in Tropical East Asia

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