scholarly journals Analysis of Cholinesterase Enzyme Activity in Rineloricaria kronei from Coastal Rivers in Southern Brazil

2013 ◽  
Vol 8 (1) ◽  
pp. 87-92
Author(s):  
Carvalho S.J. ◽  
Menezes M.S. ◽  
Guimarães A.T.B.
Keyword(s):  
Enzyme Activity ◽  
Southern Brazil ◽  
Coastal Rivers

scholarly journals Target site as the main mechanism of resistance to imazamox in a Euphorbia heterophylla biotype

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Antonia M. Rojano-Delgado ◽  
João M. Portugal ◽  
Candelario Palma-Bautista ◽  
Ricardo Alcántara-de la Cruz ◽  
Joel Torra ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Root Exudation ◽  
Acetolactate Synthase ◽  
Target Site ◽  
Southern Brazil ◽  
Fresh Weight ◽  
Weed Species ◽  
Site Mutation ◽  
Principal Mechanism ◽  
Continuous Use

Abstract Euphorbia heterophylla is a weed species that invades extensive crop areas in subtropical regions of Brazil. This species was previously controlled by imazamox, but the continuous use of this herbicide has selected for resistant biotypes. Two biotypes of E. heterophylla from southern Brazil, one resistant (R) and one susceptible (S) to imazamox, were compared. The resistance of the R biotype was confirmed by dose-response assays since it required 1250.2 g ai ha−1 to reduce the fresh weight by 50% versus 7.4 g ai ha−1 for the S biotype. The acetolactate synthase (ALS) enzyme activity was studied using ALS-inhibiting herbicides from five different chemical families. The R biotype required the highest concentrations to reduce this enzyme activity by 50%. A Ser653Asn mutation was found in the ALS gene of the R biotype. The experiments carried out showed that imazamox absorption and metabolism were not involved in resistance. However, greater 14C-imazamox root exudation was found in the R biotype (~70% of the total absorbed imazamox). Target site mutation in the ALS gene is the principal mechanism that explains the imazamox resistance of the R biotype, but root exudation seems to also contribute to the resistance of this biotype.

scholarly journals A new species of the characid genus Hollandichthys Eigenmann from coastal rivers of southern Brazil (Teleostei: Characiformes) with a discussion on the diagnosis of the genus

2013 ◽  
Vol 11 (4) ◽  
pp. 767-778 ◽  
Author(s):  
Vinicius A. Bertaco ◽  
Luiz R. Malabarba
Keyword(s):  
New Species ◽  
Black Spot ◽  
Lower Number ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Caudal Fin ◽  
Coastal Rivers ◽  
Fin Rays ◽  
Adipose Fin ◽  
A New Species

Hollandichthys taramandahy, new species, is described from the rio Tramandaí, rio Mampituba, and rio Araranguá basins, coastal drainages of Rio Grande do Sul and Santa Catarina States, Brazil. The new species is distinguished from H. multifasciatus, the single recognized species of the genus, by the presence of a small black spot covering the base of median caudal-fin rays, by the lower number of dorsal and ventral procurrent caudal-fin rays, by the absence of a black spot located along anterior half of adipose-fin, and by the absence of humeral spot in specimens larger than 60 mm of standard length. Comments about the geographic distribution and diagnosis are provided for the genus.

scholarly journals Descriptions of five new species of the Neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the rio Uruguay drainage

2015 ◽  
Vol 13 (4) ◽  
pp. 637-662 ◽  
Author(s):  
Luiz R. Malabarba ◽  
Maria Claudia Malabarba ◽  
Roberto E. Reis
Keyword(s):  
New Species ◽  
Southern Brazil ◽  
Dorsal Fin ◽  
Rio Negro ◽  
Coastal Rivers

ABSTRACT Gymnogeophagus is a Neotropical cichlid genus distributed in the río Paraguay, rio Paraná and rio Uruguay drainages and also in the coastal rivers of Uruguay and southern Brazil. Its monophyly is supported by two derived features: the absence of supraneurals and the presence of a forward spine in the first dorsal-fin pterygiophore. Herein, five new species of Gymnogeophagus are described from middle to upper tributaries of the rio Uruguay drainage and from the rio Negro. All these new species belong to a clade, which includes G. gymnogenys , easily recognized by sharing two synapomorphies: the absence of an oblique bar between the dorsal border of the eye and the nape, and the possession of a black bar originating in the dorsal contour near the dorsal-fin origin and directed downward and backward on the dorsum. A key to all species of Gymnogeophagus is provided.

scholarly journals Revisionary study of the armored catfish Corydoras paleatus (Jenyns, 1842) (Siluriformes: Callichthyidae) over 180 years after its discovery by Darwin, with description of a new species

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Luiz Fernando Caserta Tencatt ◽  
Marcelo Ribeiro de Britto ◽  
Carla Simone Pavanelli
Keyword(s):  
New Species ◽  
Posterior Margin ◽  
Unique Combination ◽  
Southern Brazil ◽  
Anterior Portion ◽  
Dorsal Fin ◽  
Black Spots ◽  
Coastal Rivers ◽  
Pectoral Spine ◽  
A New Species

ABSTRACT The taxon known as Corydoras paleatus carries one of the most complex taxonomic histories among Corydoradinae catfishes. A comprehensive review of specimens attributed to that species from several localities was carried out, allowing the clear recognition of C. paleatus and also of a new species previously misidentified as C. paleatus , described herein. Corydoras paleatus can be distinguished from its congeners by presenting the following unique combination of features: perpendicularly directed serrations along entire posterior margin of the pectoral spine; three large black blotches along midline of flank; hyaline or black pectoral fin; and transversal black bars on caudal-fin lobes. Corydoras paleatus is known from the lower rio Paraná basin, coastal rivers from Southern Brazil and Uruguay and rio Uruguai basin. The new species can be distinguished from its congeners by having the following unique combination of features: three large black blotches along midline of flank; three nasal pores; mesethmoid short; infraorbital 2 not in contact with compound pterotic; striated black spots from the snout tip to nuchal plate region; markedly rounded snout; and anterior portion of dorsal fin spotted. The new species is known from the upper rio Uruguai basin, from the rivers Canoas, do Peixe and Pelotas.

Gymnotus refugio, a new and endangered species of electric fish of the Gymnotus pantherinus species-group from southern Brazil (Gymnotiformes: Gymnotidae) 

Zootaxa ◽  
2016 ◽  
Vol 4066 (5) ◽  
pp. 581 ◽  
Author(s):  
JULIA GIORA ◽  
LUIZ ROBERTO MALABARBA
Keyword(s):  
New Species ◽  
Endangered Species ◽  
Electric Fish ◽  
Rio Grande ◽  
Species Group ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Meristic Characters ◽  
Coloration Pattern ◽  
Coastal Rivers

Gymnotus refugio, new species, is described from coastal rivers of Rio Grande do Sul and Santa Catarina states, Brazil. It is diagnosed from most species of the Gymnotus pantherinus species-group by the coloration pattern, further differing from G. pantherinus and G. capitimaculatus on the basis of morphometric and meristic characters. The new species represents the most meridional record of the G. pantherinus species-group. 

Morphological and biochemical analyses of changes in rat hepatocytes related to wine and ethanol consumption

1984 ◽  
Vol 42 ◽  
pp. 232-233
Author(s):  
S.M. Geyer ◽  
C.L. Mendenhall ◽  
J.T. Hung ◽  
E.L. Cardell ◽  
R.L. Drake ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Enzyme Activity ◽  
Malic Enzyme ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Mature Male ◽  
Treatment Groups ◽  
Malic Enzyme Activity ◽  
Biochemical Analyses

Thirty-three mature male Holtzman rats were randomly placed in 3 treatment groups: Controls (C); Ethanolics (E); and Wine drinkers (W). The animals were fed synthetic diets (Lieber type) with ethanol or wine substituted isocalorically for carbohydrates in the diet of E and W groups, respectively. W received a volume of wine which provided the same gram quantity of alcohol consumed by E. The animals were sacrificed by decapitation after 6 weeks and the livers processed for quantitative triglycerides (T3), proteins, malic enzyme activity (MEA), light microscopy (LM) and electron microscopy (EM). Morphometric analysis of randomly selected LM and EM micrographs was performed to determine organellar changes in centrilobular (CV) and periportal (PV) regions of the liver. This analysis (Table 1) showed that hepatocytes from E were larger than those in C and W groups. Smooth endoplasmic reticulum decreased in E and increased in W compared to C values.

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