Genomic and phenotypic attributes of novel salinivibrios from stromatolites, sediment and water from a high altitude lake

Background: Salinivibrios are moderately halophilic bacteria found in salted meats, brines and hypersaline environments. We obtained three novel conspecific Salinivibrio strains closely related to S. costicola, from Socompa Lake, a high altitude hypersaline Andean lake (approx. 3,570 meters above the sea level).Results: The three novel Salinivibrio spp. were extremely resistant to arsenic (up to 200 mM HAsO42-), NaCl (up to 15%), and UV-B radiation (19 KJ/m2, corresponding to 240 minutes of exposure) by means of phenotypic tests. Our subsequent draft genome ionsequencing and RAST-based genome annotation revealed the presence of genes related to arsenic, NaCl, and UV radiation resistance. The three novel Salinivibrio genomes also had the xanthorhodopsin gene cluster phylogenetically related to Marinobacter and Spiribacter. The genomic taxonomy analysis, including multilocus sequence analysis, average amino acid identity, and genome-to-genome distance revealed that the three novel strains belong to a new Salinivibrio species.Conclusions: Arsenic resistance genes, genes involved in DNA repair, resistance to extreme environmental conditions and the possible light-based energy production, may represent important attributes of the novel salinivibrios, allowing these microbes to thrive in the Socompa Lake. © 2014 Gorriti et al.; licensee BioMed Central Ltd.Fil: Gorriti, Marta Fabiana. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; ArgentinaFil: Dias, Graciela M.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Chimetto, Luciane A.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Trindade-Silva, Amaro E.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Silva, Bruno S.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Mesquita, Milene M.A.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Gregoracci, Gustavo B.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Farias, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; ArgentinaFil: Thompson, Cristiane C.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; BrasilFil: Thompson, Fabiano L.. Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brasil ; Brasi

The molecular logic of endocannabinoid signalling

The endocannabinoids are a family of lipid messengers that engage the cell surface receptors that are targeted by Δ9-tetrahydrocannabinol, the active principle in marijuana (Cannabis). They are made on demand through cleavage of membrane precursors and are involved in various short-range signalling processes. In the brain, they combine with CB1 cannabinoid receptors on axon terminals to regulate ion channel activity and neurotransmitter release. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. © 2003, Nature Publishing Group. All rights reserved

Role of the endogenous cannabinoid system as a modulator of dopamine transmission: implications for Parkinson's disease and schizophrenia.

The endogenous cannabinoid system is a new signaling system composed by the central (CB1) and the peripheral (CB2) receptors, and several lipid transmitters including anandamide and 2-arachidonylglycerol. This system is the target of natural cannabinoids, the psychoactive constituents of Cannabis sativa preparations (marijuana, hashish). Acute and chronic cannabis exposure has been associated with subjective feelings of pleasure and relaxation, but also to the onset of psychiatric syndromes, a decrease of the efficacy of neuroleptics and alterations in the extrapyramidal system regulation of motor activity. These actions point to a tight association of the cannabinoid system with the brain dopaminergic circuits involved in addiction, the clinical manifestation of positive symptoms of schizophrenia and Parkinson's disease. The present work discusses anatomical, biochemical and pharmacological evidences supporting a role for the endogenous cannabinoid system in the modulation of dopaminergic transmission. Cannabinoid CB1 receptors are present in dopamine projecting brain areas. In primates and certain rat strains it is also located in dopamine cells of the A8, A9 and A10 mesencephalic cell groups, as well as in hypothalamic dopaminergic neurons controlling prolactin secretion. CB1 receptors co-localize with dopamine D1/D2 receptors in dopamine projecting fields. Manipulation of dopaminergic transmission is able to alter the synthesis and release of anandamide as well as the expression of CB1 receptors. Additionally, CB1 receptors can switch its transduction mechanism to oppose to the ongoing dopamine signaling. Acute blockade of CB1 receptor potentiates the facilitatory role of dopamine D2 receptor agonists on movement. CB1 stimulation results in sensitization to the motor effects of indirect dopaminergic agonists. The dynamics of these changes indicate that the cannabinoid system is an activity-dependent modulator of dopaminergic transmission, an hypothesis relevant for the design of new therapeutic strategies for dopamine-related diseases such as the psychosis and Parkinson's disease

Reversal of dopamine D(2) receptor responses by an anandamide transport inhibitor.

We characterized the pharmacological properties of the anandamide transport inhibitor N-(4-hydroxyphenyl)-arachidonamide (AM404) in rats and investigated the effects of this drug on behavioral responses associated with activation of dopamine D(2) family receptors. Rat brain slices accumulated [(3)H]anandamide via a high-affinity transport mechanism that was blocked by AM404. When administered alone in vivo, AM404 caused a mild and slow-developing hypokinesia that was significant 60 min after intracerebroventricular injection of the drug and was reversed by the CB1 cannabinoid receptor antagonist SR141716A. AM404 produced no significant catalepsy or analgesia, two typical effects of direct-acting cannabinoid agonists. However, AM404 prevented the stereotypic yawning produced by systemic administration of a low dose of apomorphine, an effect that was dose-dependent and blocked by SR141716A. Furthermore, AM404 reduced the stimulation of motor behaviors elicited by the selective D(2) family receptor agonist quinpirole. Finally, AM404 reduced hyperactivity in juvenile spontaneously hypertensive rats, a putative model of attention deficit hyperactivity disorder. The results support a primary role of the endocannabinoid system in the regulation of psychomotor activity and point to anandamide transport as a potential target for neuropsychiatric medicines

Reversal of dopamine D(2) receptor responses by an anandamide transport inhibitor.

We characterized the pharmacological properties of the anandamide transport inhibitor N-(4-hydroxyphenyl)-arachidonamide (AM404) in rats and investigated the effects of this drug on behavioral responses associated with activation of dopamine D(2) family receptors. Rat brain slices accumulated [(3)H]anandamide via a high-affinity transport mechanism that was blocked by AM404. When administered alone in vivo, AM404 caused a mild and slow-developing hypokinesia that was significant 60 min after intracerebroventricular injection of the drug and was reversed by the CB1 cannabinoid receptor antagonist SR141716A. AM404 produced no significant catalepsy or analgesia, two typical effects of direct-acting cannabinoid agonists. However, AM404 prevented the stereotypic yawning produced by systemic administration of a low dose of apomorphine, an effect that was dose-dependent and blocked by SR141716A. Furthermore, AM404 reduced the stimulation of motor behaviors elicited by the selective D(2) family receptor agonist quinpirole. Finally, AM404 reduced hyperactivity in juvenile spontaneously hypertensive rats, a putative model of attention deficit hyperactivity disorder. The results support a primary role of the endocannabinoid system in the regulation of psychomotor activity and point to anandamide transport as a potential target for neuropsychiatric medicines

Cerebrospinal Anandamide Levels are Elevated in Acute Schizophrenia and are Inversely Correlated with Psychotic Symptoms

The endocannabinoids are a family of bioactive lipids that activate CB1 cannabinoid receptors in the brain and exert intense emotional and cognitive effects. Here, we have examined the role of endocannabinoid signaling in psychotic states by measuring levels of the endocannabinoid anandamide in cerebrospinal fluid (CSF) of acute paranoid-type schizophrenic patients. We found that CSF anandamide levels are eight-fold higher in antipsychotic-naïve first-episode paranoid schizophrenics (n 47) than healthy controls (n 84), dementia patients (n 13) or affective disorder patients (n 22). Such an alteration is absent in schizophrenics treated with ‘typical ’ antipsychotics (n 37), which antagonize dopamine D2-like receptors, but not in those treated with ‘atypical ’ antipsychotics (n 34), which preferentially antagonize 5HT2A receptors. Furthermore, we found that, in nonmedicated acute schizophrenics, CSF anandamide is negatively correlated with psychotic symptoms (rS 0.452, P 0.001). The results suggest that anandamide elevation in acute paranoid schizophrenia may reflect a compensatory adaptation to the disease state

TPX2/Aurora kinase A signaling as a potential therapeutic target in genomically unstable cancer cells

Genomic instability is a hallmark feature of cancer cells, and can be caused by defective DNA repair, for instance due to inactivation of BRCA2. Paradoxically, loss of Brca2 in mice results in embryonic lethality, whereas cancer cells can tolerate BRCA2 loss. This holds true for multiple DNA repair genes, and suggests that cancer cells are molecularly "rewired" to cope with defective DNA repair and the resulting high levels of genomic instability. In this study, we aim to identify genes that genomically unstable cancer cells rely on for their survival. Using functional genomic mRNA (FGmRNA) profiling, 16,172 cancer samples were previously ranked based on their degree of genomic instability. We analyzed the top 250 genes that showed a positive correlation between FGmRNA levels and the degree of genomic instability, in a co-functionality network. Within this co-functionality network, a strong cluster of 11 cell cycle-related genes was identified, including TPX2. We then assessed the dependency on these 11 genes in the context of survival of genomically unstable cancer cells, induced by BRCA2 inactivation. Depletion of TPX2 or its associated kinase Aurora-A preferentially reduced cell viability in a panel of BRCA2-deficient cancer cells. In line with these findings, BRCA2-depleted and BRCA2-mutant human cell lines, or tumor cell lines derived from Brca2(-/-); p53(-/-) mice showed increased sensitivity to the Aurora-A kinase inhibitor alisertib, with delayed mitotic progression and frequent mitotic failure. Our findings reveal that BRCA2-deficient cancer cells show enhanced sensitivity to inactivation of TPX2 or its partner Aurora-A, which points at an actionable dependency of genomically unstable cancers