SCHIZACHYRIUM HATSCHBACHII (POACEAE), NUEVO REGISTRO PARA LAFLORA ARGENTINA

Schizachyrium hatschbachii Peichoto is cited for the first time for the Argentinian flora. Some ecological observations and the key to differentiate it from related species are includedSe cita a Schizachyrium hatschbachii Peichoto por primera vez para la flora argentina. Seincluyen algunas observaciones ecológicas y una clave para diferenciarla de las entidadesafine

Digestión de láminas foliares de Paspalum notatum sometidas a diferentes tiempos de incubación ruminal en bovinos

In order to evaluate the ruminal degradation of Paspalum notatum (grass pasture) in rumen of bovines at different times of the year, in a field of northeastern Argentina, samples of this pasture were collected at 15, 30 and 45 days of regrowth, were cut and placed 5 g in dacron bags, to be introduced in the rumen at 120, 72, 48, 24, 12, 6, 3 and 0 hours, and removed at the same time, an aliquot was fixed in acetoalcoholic formalin solution (FAA), dehydrated with acetone and mounted on aluminum foil and metallized for observation in scanning microscope (MEB). The degradation of the tissues was determined according to the state of the cell walls. Four categories were established: D: highly degraded; DA: advanced degradation; PD: partially degraded; ND: not degraded. In autumn, the cut from 15 days to 12 hours, the disappearance of the chlorenchyma (mesophyll) was advanced and the phloem beganto be digested. After 48 hours, some paranchymalcells of the beam sheath remained undigested. At 30 days and 48 hours of incubation, mesophyll and phloem suffered complete degradation. At 45 days instead, he only showed a complete digestion for the chlorenchyme, the phloem presented advanced digestion. In winter, at 24 hours on lythex ylem tissues and abaxial sclerench y maremained. After 48 hours in rumen the only thing not digested was xylem, sclerenchyma and sheath of the beam. The mesophyll and the phloem, at 15 days and 24 hours, were digested 100%, for 30 and 45 days, advanced digestion was observed. In spring, the three ages showed chlorenchyme, phloem, and partially degraded sheath at 12 hours, the 24-hour the reveal e advanced degradation and complete digestion after 48 hours. The xylem, was degraded in it sentir et y to 48 hours of the cut of 15 days, instead for 30 and 45 days, the degradation was advanced . In summer the behavior was similar to spring. In general terms the anatomical characteristics observed, in the thre eages of cut and different seasons were variable fort his species.Con el objetivo de evaluar la degradación ruminal de Paspalum notatum (pasto horqueta) en rumen de bovinos en distintas épocas del año, en un campo del nordeste argentino se recolectaron muestras de dicha pastura a los 15, 30 y 45 días de rebrote, se cortaron y colocaron 5 g en bolsas de dacrón, para ser introducidas en el rumen a 120; 72; 48; 24; 12; 6; 3 y 0 horas, y retiradas al mismo tiempo. Una alícuota se fijó en solución de formol aceto-alcohólica (FAA), se deshidrató con acetona y montó en lámina de aluminio y metalizó para observación en microscopio de barrido (MEB). Se determinó la degradación de los tejidos según el estado de las paredes celulares. Se establecieron cuatro categorías: D: altamente degradado; DA: degradación avanzada; PD: parcialmente degradado; ND: no degradado. En otoño, el corte de 15 días a 12 h, la desaparición del clorénquima (mesófilo) fue avanzado, y el floema comenzó a ser digerido. Luego de 48 h algunas células paranquimáticas de la vaina del haz permanecieron sin digerir. A 30 días y 48 h de incubación, mesófilo y floema sufrieron degradación completa. A 45 días en cambio solo mostró una digestión completa para el clorénquima, el floema presentó digestión avanzada. En invierno, a 24 hs solo permanecieron los tejidos xilemáticos y casquete de esclerénquima abaxial. Al cabo de 48 h en rumen lo único no digerido fue xilema, esclerénquima y vaina del haz. El mesófilo y el floema, a los 15 días y 24 horas, se digirieron en un 100%, para 30 y 45 días, se observó una digestión avanzada. En primavera las tres edades, mostraron clorénquima, floema, y vaina del haz parcialmente degradados a las 12 h, el in situ de 24 h reveló degradación avanzada y digestión completa luego de 48 h. El xilema, se degradó totalmente a 48 h de incubación en el corte de 15 días, en cambio para 30 y 45 días, la degradación fue avanzada. En verano el comportamiento fue similar a primavera. En términos generales las características anatómicas observadas, en las tres edades de corte y distintas estaciones fueron variables para esta especie

Variabilidad y estructura genética de poblaciones de Schizachyrium (Poaceae, Andropogoneae) de la provincia de Corrientes (Argentina)

A fin de evaluar la utilidad de los estudios genético-poblacionales en la identificación de especies de Schizachyrium y en el papel de la hibridación natural en la evolución de dichas especies, se analizó la variabilidad y estructura genética de S. bimucronatum, S. sanguineum y S. tenerum. La identificación de bandas RAPDs y haplotipos de ADNcp exclusivos, sumados a los resultados del PCoA y AMOVA evidenciaron que dichas especies difieren genéticamente entre sí. La consistencia de estos resultados con la distinción de grupos morfológicos definidos previamente, sugiere que los análisis genético-poblacionales basados en marcadores nucleares y de cloroplastos combinados podrían contribuir a la identificación inequívoca de las especies de Schizachyrium. Asimismo, el hallazgo de algunos individuos con una proporción de sus genomas asignable a los de otras poblaciones o especies, sugiere la ocurrencia de eventos de hibridación seguida de introgresión o de poliploidización. Finalmente, los patrones de estructuración genética observados estarían relacionados a las características de los sistemas reproductivos de las especies estudiadas; mientras que la identificación de unidades evolutivas independientes en dichas especies sería de interés para el desarrollo de estrategias de conservación de las especies y de las comunidades que integran

A transcriptomic analysis of gene expression in the venom gland of the snake Bothrops alternatus (urutu)

<p>Abstract</p> <p>Background</p> <p>The genus <it>Bothrops </it>is widespread throughout Central and South America and is the principal cause of snakebite in these regions. Transcriptomic and proteomic studies have examined the venom composition of several species in this genus, but many others remain to be studied. In this work, we used a transcriptomic approach to examine the venom gland genes of <it>Bothrops alternatus</it>, a clinically important species found in southeastern and southern Brazil, Uruguay, northern Argentina and eastern Paraguay.</p> <p>Results</p> <p>A cDNA library of 5,350 expressed sequence tags (ESTs) was produced and assembled into 838 contigs and 4512 singletons. BLAST searches of relevant databases showed 30% hits and 70% no-hits, with toxin-related transcripts accounting for 23% and 78% of the total transcripts and hits, respectively. Gene ontology analysis identified non-toxin genes related to general metabolism, transcription and translation, processing and sorting, (polypeptide) degradation, structural functions and cell regulation. The major groups of toxin transcripts identified were metalloproteinases (81%), bradykinin-potentiating peptides/C-type natriuretic peptides (8.8%), phospholipases A₂(5.6%), serine proteinases (1.9%) and C-type lectins (1.5%). Metalloproteinases were almost exclusively type PIII proteins, with few type PII and no type PI proteins. Phospholipases A₂were essentially acidic; no basic PLA₂were detected. Minor toxin transcripts were related to L-amino acid oxidase, cysteine-rich secretory proteins, dipeptidylpeptidase IV, hyaluronidase, three-finger toxins and ohanin. Two non-toxic proteins, thioredoxin and double-specificity phosphatase Dusp6, showed high sequence identity to similar proteins from other snakes. In addition to the above features, single-nucleotide polymorphisms, microsatellites, transposable elements and inverted repeats that could contribute to toxin diversity were observed.</p> <p>Conclusions</p> <p><it>Bothrops alternatus </it>venom gland contains the major toxin classes described for other <it>Bothrops </it>venoms based on trancriptomic and proteomic studies. The predominance of type PIII metalloproteinases agrees with the well-known hemorrhagic activity of this venom, whereas the lower content of serine proteases and C-type lectins could contribute to less marked coagulopathy following envenoming by this species. The lack of basic PLA₂agrees with the lower myotoxicity of this venom compared to other <it>Bothrops </it>species with these toxins. Together, these results contribute to our understanding of the physiopathology of envenoming by this species.</p

Schizachyrium hatschbachii (Poaceae), new record for Argentinian flora

Schizachyrium hatschbachii&nbsp;Peichoto is cited for the first time for the Argentinian flora. Some ecological observations and the key to differentiate it from related species are included</span

Platelet participation in the pathogenesis of dermonecrosis induced by Loxosceles gaucho venom

Loxosceles gaucho spider venom induces in vitro platelet activation and marked thrombocytopenia in rabbits. Herein, we investigated the involvement of platelets in the development of the dermonecrosis induced by L. gaucho venom, using thrombocytopenic rabbits as a model. L. gaucho venom evoked a drop in platelet and neutrophil counts 4 h after venom injection. Ecchymotic areas at the site of venom inoculation were noticed as soon as 4 h in thrombocytopenic animals but not in animals with initial normal platelet counts. After 5 days, areas of scars in thrombocytopenic animals were also larger, evidencing the marked development of lesions in the condition of thrombocytopenia. Histologically, local hemorrhage, collagen fiber disorganization, and edema were more severe in thrombocytopenic animals. Leukocyte infiltration, predominantly due to polymorphonuclears, was observed in the presence or not of thrombocytopenia. Thrombus formation was demonstrated by immunohistochemistry at the microvasculature, and it occurred even under marked thrombocytopenia. Taken together, platelets have an important role in minimizing not only the hemorrhagic phenomena but also the inflammatory and wound-healing processes, suggesting that cutaneous loxoscelism may be aggravated under thrombocytopenic conditions.Fil: Tavares, F. L.. Instituto Butantan. Laboratório de Fisiopatologia; BrasilFil: Peichoto, María Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Medicina Tropical ; ArgentinaFil: Marcelino, J. R.. Instituto Butantan. Divisão de Desenvolvimento Tecnológico e Produção; BrasilFil: Barbaro, K. C.. Instituto Butantan. Laboratório de Imunopatologia; BrasilFil: Cirillo, M. C.. Instituto Butantan. Laboratório de Fisiopatologia; BrasilFil: Santoro, Marcelo Larami. Instituto Butantan. Laboratório de Fisiopatologia; BrasilFil: Sano Martins, I. S.. Instituto Butantan. Laboratório de Fisiopatologia; Brasi

Purification and characterization of a cysteine-rich secretory protein from Philodryas patagoniensis snake venom

Cysteine-rich secretory proteins (CRiSPs) are widespread in reptile venoms, but most have functions that remain unknown. In the present study we describe the purification and characterization of a CRiSP (patagonin) from the venom of the rear-fanged snake Philodryas patagoniensis, and demonstrate its biological activity. Patagonin is a single-chain protein, exhibiting a molecular mass of 24,858.6 Da, whose NH2-terminal and MS/MS-derived sequences are nearly identical to other snake venom CRiSPs. The purified protein hydrolyzed neither azocasein nor fibrinogen, and it could induce no edema, hemorrhage or inhibition of platelet adhesion and aggregation. In addition, patagonin did not inhibit contractions of rat aortic smooth muscle induced by high K+. However, it caused muscular damage to murine gastrocnemius muscle, an action that has not been previously described for any snake venom CRiSPs. Thus, patagonin will be important for studies of the structure-function and evolutionary relationships of this family of proteins that are widely distributed among snake venoms. © 2009 Elsevier Inc. All rights reserved.Fil: Peichoto, María Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste; Argentina. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Mackessy, Stephen P.. Univeristy of Northern Colorado; Estados UnidosFil: Teibler, Gladys Pamela. Universidad Nacional del Nordeste; ArgentinaFil: Tavares, Flávio L.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Burckhardt, Paula L.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Breno, María C.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Acosta, Ofelia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste; ArgentinaFil: Santoro, Marcelo Larami. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasi