Compositional and toxicological investigation of pooled venom from farm-raised Naja atra

Background: Naja atra is a venomous snake species medically relevant in China. In the current study, we evaluated the composition and toxicological profile of venom collected from farm-raised N. atra. Methods: Venom was collected from third-generation captive bred N. atra on a snake farm in Hunan Province, China. The venom was analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and nano-liquid chromatography with electrospray ionization tandem mass spectrometry. In addition, hemolytic activity, median lethal dose, serum biochemical and histopathological parameters were accessed. Results: N. atra venom proteome was dominated by phospholipase A2 (46.5%) and three-finger toxins (41.4 %), and a set of common low relative abundance proteins, including cysteine-rich secretory proteins (4.7%), NGF-beta (2.4%), snake venom metalloproteinase (1.5%), glutathione peroxidase (0.6%), vespryn (0.3%), and 5ʹ-nucleotidases (0.2%) were also found. Furthermore, the venom exhibited direct hemolytic activity, neurotoxicity, myotoxicity, and high lethal potency in mice, with a subcutaneous median lethal dose of 1.02 mg/kg. Histopathological analysis and serum biochemical tests revealed that venom caused acute hepatic, pulmonary and renal injury in mice. Conclusion: This study revealed the composition and toxicity of venom collected from farm-raised N. atra, thereby providing a reference for the analysis of venom samples collected from captive-born venomous snakes in the future.(AU)

Protective effect of CD73 inhibitor α, ß-methylene ADP against amyloid-ß-induced cognitive impairment by inhibiting adenosine production in hippocampus

BACKGROUND: Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disease. Recent studies have reported the close association between cognitive function in AD and purinergic receptors in the central nervous system. In the current study, we investigated the effect of CD73 inhibitor α, ß-methylene ADP (APCP) on cognitive impairment of AD in mice, and to explore the potential underlying mechanisms. RESULTS: We found that acute administration of Aß1­42 (i.c.v.) resulted in a significant increase in adenosine release by using microdialysis study. Chronic administration of APCP (10, 30 mg/kg) for 20 d obviously mitigated the spatial working memory impairment of Aß1­42-treated mice in both Morris water maze (MWM) test and Y-maze test. In addition, the extracellular adenosine production in the hippocampus was inhibited by APCP in Aß-treated mice. Further analyses indicated expression of acetyltransferase (ChAT) in hippocampus of mice of was significantly reduced, while acetylcholinesterase (AChE) expression increased, which compared to model group. We observed that APCP did not significantly alter the NLRP3 inflammasome activity in hippocampus, indicating that anti-central inflammation seems not to be involved in APCP effect. CONCLUSIONS: In conclusion, we report for the first time that inhibition of CD73 by APCP was able to protect against memory loss induced by Aß1­42 in mice, which may be due to the decrease of CD73-driven adenosine production in hippocampus. Enhancement of central cholinergic function of the central nervous system may also be involved in the effects of APCP.

Analysis of CANT1 gene variant in a girl with Desbuquois dysplasia type I / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with scoliosis, congenital dislocation of the hip joint and growth retardation by using next generation sequencing (NGS).@*METHODS@#Peripheral blood samples were obtained from the proband and his parents. Whole genomic DNA was extracted and subjected to NGS. Suspected variant was predicted by bioinformatic tools and validated by Sanger sequencing.@*RESULTS@#The proband was found to carry compound heterozygous variants c.494T>C (p.Met165Thr) and c.848A>G (p.His283Arg) of the CANT1 gene, among which c.494T>C (p.Met165Thr) was inherited from her father and reported to be pathogenic by HGMD. c.848A>G (p.His283Arg) was inherited from her mother and was predicted to be likely pathogenic according to the ACMG 2015 guidelines.@*CONCLUSION@#The compound heterozygous variants of c.494T>C (p.Met165Thr) and c.848A>G (p.His283Arg) of the CANT1 gene probably underlie the disease in the proband.

Señales purinérgicas / Purinergic signals

En la última década se ha aportado clara evidencia de que tanto nucleósidos como nucleótidos de adenina y uridina pueden funcionar como factores de señalización extracelular. Su acción es mediada por dos tipos principales de receptores de superficie denominados purinérgicos. Los receptores P1 se activan por adenosina, y son todos metabotrópicos, mientras que los receptores de nucleótidos (ATP, ADP, UTP y UDP) y nucleótidos-azúcares (UDP-glucosa y UDP-galactosa) pueden ser metabotrópicos (P2Y) o ionotrópicos (P2X). La importancia y complejidad de este sistema de señalización se evidencia por la diversidad de mecanismos de liberación de nucleótidos al medio extracelular y por la distribución ubicua de varios grupos de ectonucleotidasas capaces de catalizar la degradación y conversión de nucleótidos. Hasta el momento se han descrito y clonado una veintena de estos receptores que modulan una variedad de respuestas, como el impulso nervioso, la respuesta inflamatoria, la secreción de insulina, la regulación del tono vascular y la percepción del dolor. En la presente revisión se describen las características estructurales y farmacológicas de los receptores purinérgicos y se analiza la interacción dinámica entre estos receptores, los nucleósidos y nucleótidos, y las ectonucleotidasas, con especial atención a la dinámica de la agregación plaquetaria, la respuesta inmune y la hidratación de las mucosas respiratorias.

In the last decade evidence accumulated that nucleosides and nucleotides of both uridine and adenine can act as extracellular signaling factors. Their action is mediated by two main types of surface receptors commonly known as purinergic. P1 receptors are metabotropic and activated by adenosine, whereas receptors for nucleotides (ATP, ADP, UTP and UDP) and nucleotide-sugars (UDP-glucose and UDP-galactose) can be either metabotropic (P2Y) or ionotropic (P2X). The importance and complexity of this signaling system is evidenced by various mechanisms of nucleotide release, as well as by the ibiquitous distribution of various types of ectonucleotidases which catalyze and convert extracellular nucleotides. Up to now about twenty receptors have been cloned and found to modulate the nerve impulse, inflammatory response, insuline secretion, the regulation of the vascular tone and nociception, among other processes. In the present review we describe the main structural and pharmacological features of purinergic receptors, and analyze how the dynamic interaction between these receptors, nucleotides and nucleosides, and ectonucleotidases modulate several biological responses. Particular focus is given to platelet aggregation and thrombus formation, the immune response and the hydration of the mucosal linings of the respiratory tract.

The ecto-ATPases of endoparasites and of blood cells and vessels

The cells of blood vessel walls and the external surface of all blood cells have an ecto-ATPase which hydrolyzes ATP to ADP and also ADP to AMP. This enzyme has also been called apyrase or ATP-diphosphohydrolase. The enzyme hydrolyzes a broad range of tri-and diphosphate nucleosides such as UTP and UDP, GTP and GDP in additon to the adenine nucleotides and because of that it has also been called a nucleoside triphosphate hydrolase. The possible physiological roles for this ecto-ATPase involve the control of vascular tone by modulation of the levels of ATP and ADP binding to purino-receptors of the vasculature, the modulation of thrombogenesis by controlling the extracellular level of ADP which is known to activate platelet aggregation, and the protection from cytolytic effects of extracellular ATP. An ATP-diphosphohydrolase activity has been characterized on the external surface of Schistosoma mansoni, a parasite that lives in the circulation of the human host, and on the outer surface of Entamoeba histolytica, a parasite that may enter the circulation of the host through ulceration in the intestinal mucosa. The endoparasite Toxoplasma gondii also exhibits a nucleoside triphosphate hydrolase of high activity, although in this case the ecto-localization is still not documented. We raise the possibility that the endoparasites have evolved in a way to possibly mimic some of the conditions on the surface of cells normally present in the host circulation, thus escaping hemostatic defense responses of the host which require extracellular ADP or ATP.

Leishmania mexicana amazonenesis: heterogeneity in 5-nucleotidase and peroxidase activities of mononuclear phagocytes during in vivo and in vitro infection

Um estudo sobre o grau de maturaçäo das células do Sistema Fagocítico Mononuclear foi realizado durante a infecçäo in vivo e in vitro com a Leishmania mexicana amazonensis. A caracterizaçäo da diferenciaçäo das células fagocíticas foi obtida com a localizaçäo ultraestrutural de dois marcadores enzimáticos bam conhecidos: a enzima 5'-Nucleotidase marcadora de membrana plasmática de células maduras e a enzima peroxidase, presente em grânulos, marcadora de células imaturas. A atividade da enzima 5'-Nucleotidase foi encontrada apenas em alguns macrófagos, presentes no foco inflamatório, em projeçöes da membrana plasmática e em algumas vesículas citoplasmáticas. Macrófagos peritoneais de camundongo apresentaram a mesma reatividade para este marcador. Contudo a análise da atividade peroxidásica demonstrou a predominância da presença de fagócitos mononucleares imaturos nas lesöes crônicas induzidas neste sistema por Leishmania mexicana amazonensis

Early changes in bile secretion following relief of short-term biliary obstruction in the rat

Se estudiaron los efectos que produce una obstrucción biliar extrahepática de 2 h en la rata después de liberada la interrupción del flujo biliar (FB). Las actividades plasmáticas de fosfatasa alcalina y 5'-nucleotidasa aumentaron luego de la obstrucción. El aumento de la coleresis post-obstructiva fue debido a la mayor excreción biliar de ácidos biliares acumulados durante la obstrucción, la cual no fue acompañada por otros lípidos, como ocurre en ratas normales. La inyección en bolo de taurocolato de sodio (TC) puso de manifiesto una capacidad disminuida pra ser secretado en bilis y además, una disminución de la eficiencia colerética. A su vez, las ratas post-colestásicas mostraron una gran susceptibilidad al efecto inhibitorio del TC sobre el FB independiente de sales biliares. Dichas alteraciones podrían reflejar importantes daños en la membrana ocasionados por la salbiliar excretada, a pesar del corto período de la obstrucción, así como que las alteraciones observadas del FB dependiente e independiente de sales biliares pueden ser atribuidas a una incapacidad para reparar membranas en las ratas post-colestásicas

Determinación automatizada de la 5'-nucleotidasa sérica: evaluación de dos métodos / Automatized determination of the serum 5'-nucleotidase: evaluation of 2 methods

Se determinó la actividad de la 5'-nucleotidasa sérica mediante los métodos de Arkesteijn (J. Clin. Chem. Clin. Biochem., 14, 155, 1976) y de Bertrand-Buret (Clin. Chim. Acta, 119. 275. 1982) en los autoanalizadores Hitachi-737 y CentrifiChem-600. La precisión obtenida puede considerarse buena de acuerdo con el criterio del Colegio Americano de Patólogos y se obtuvo una elevada correlación entre ambos métodos (r >-0,985)

Contenido proteico y actividades enzimáticas presentes en el veneno de la araña casera - Loxosceles laeta: II Parte / Protein content and enzymatic activities present in the poison of the house spider - Loxosceles laeta: Part II

Se ha investigado el contenido proteico y varias actividades enzimáticas en el veneno de la araña casera Loxosceles laeta. La cantidad de proteína encontrada en 3 de los 4 lotes de arañas en estudio fue de 38 ug por especímen. Asi mismo, se ha encontrado actividad de 5 nucleotidasa, fosfatasa ácida y alcalina, ADPasa y ATPasa, enzima cascinolítica y hialuronidasa. En cambio, no se ha registrado actividad de exonucleasa, endonucleasa, enzima semejante a trombina, enzima fibrinolítica, ni actividad esterásica

Actividad de una 5' nucleotidasa en el veneno de la serpiente Bothrops atrox (L.) "Jergon". / Activity of 5' nucleotidase in the venom of Bothrops atrox (L.) \"Jergon\"

Se ha estudiado las caracteristicas de una 5'nucleotidasa del veneno de Bothrops atrox (L.). La enzima muestra variacion de pH optico en un rango que fluctua entre 6,2 a 8,2 con buffer Tris-HCI y un pico a 8,6 con buffer Glicina-NaOH, mostrando una mayor afinidad con este ultimo.Estos valores de actividad son modificados por accion de magnesio 5 mM. Los iones calcio producen inhibicion de actividad enzimatica en grado variable, mientras que el magnesio es un ion activador, evidenciandose competencia ionica a valores de pH mayores que 8,6. Asi mismo se ha encontrado que la enzima es sensible al efecto termino, a la accion de agentes quelantes como citrato de sodio, EDTA y a L-aminoacidos como: glicina, prolina, ac. glutamico y lisina.En cambio los agentes reductores 2-Mercaptoetanol y L-Cisteina causan notable incremento de la actividad de la enzima a pH 8,6 con buffer Tris-HCl. La adicion de magnesio 5 mM e mezclas de reaccion que contienen L-aminoacidos incrementan la velocidad de hidrolisis