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Dalmacio Vélez Sársfield, Argentina

Blariza M.J.,National University of Cordoba | Soria N.W.,Laboratorio Of Analisis Clinicos Especializados Lace | Torres A.G.,National University of Cordoba | Grosso C.G.,National University of Cordoba | Garcia B.A.,National University of Cordoba
Gene | Year: 2014

Two vitellogenin genes (Vg1 and Vg2) were identified in the Chagas' disease vector Triatoma infestans. The putative coding sequence corresponding to Vg2 was found to be 5553. bp long, encoding 1851 amino acids in a single open reading frame. The comparative analysis of the deduced amino acid sequences from Vg1 and Vg2 cDNA fragments of T. infestans revealed 58.94% of identity with 76.43% of homology. The phylogenetic tree based on the complete Vg amino acid sequences of hemimetabolous insects unambiguously supported two clusters, one consisting of Vg sequences from dictyopteran and the other containing Vg sequences of hemipteran. The Vg1 and Vg2 mRNAs were detected in fat bodies and ovaries of adult females with the highest levels of both Vg transcripts in the first tissue. Quantitative PCR showed low expression of Vg2 in head and muscle of adult females, while the Vg1 transcript was not present in these organs. Neither Vg1 nor Vg2 was expressed in fifth instar nymph fat bodies or in adult male fat bodies, heads, and muscles. © 2014 Elsevier B.V.

Blariza M.J.,National University of Cordoba | Leyria J.,National University of Cordoba | Canavoso L.E.,National University of Cordoba | Soria N.W.,Laboratorio Of Analisis Clinicos Especializados Lace | Garcia B.A.,National University of Cordoba
Acta Tropica | Year: 2016

The reproductive success of all oviparous species depends on vitellogenin (Vg) biosynthesis and its accumulation in the developing oocytes. The expression levels of two Vg genes (Vg1 and Vg2) were analyzed by qPCR and western blot in fat body and ovaries of adult females, at different times after ecdysis (pre-vitellogenic phase) and after blood feeding of females (vitellogenic phase). Vg genes were also evaluated in fat bodies of adult males as well as in female fifth instar nymphs. No trace of Vg mRNA was detected in adult males or in nymphs. Vg1 and Vg2 were expressed in the fat bodies and ovaries of adult females. The Vg genes start to be expressed slightly in both tissues of adult females during pre-vitellogenesis. After blood feeding, Vg1 and Vg2 were up regulated and significant levels of Vg transcripts as well as protein expression were observed in fat bodies sampled throughout vitellogenesis. During this period however, the distribution patterns of Vg1 and Vg2 transcripts showed two peaks around early and advanced vitellogenesis (days 4 and 12 post-feeding, respectively). In the ovaries, levels of mRNAs increased from the day 10 post-blood feeding onwards. In addition, the immunofluorescence assays showed a strong signal for vitellin in the yolk bodies of terminal follicles of vitellogenic females. The involvement of fat body and ovary in the synthesis of Vg suggests different roles of Vgs in supporting the growth of oocytes. © 2016 Elsevier B.V.

Della Costa N.S.,National University of Cordoba | Marin R.H.,National University of Cordoba | Busso J.M.,National University of Cordoba | Hansen C.,Laboratorio Of Analisis Clinicos Especializados Lace | And 2 more authors.
Zoo Biology | Year: 2016

Many environmental conditions elevate plasma corticosterone in laying birds, leading to elevated hormone accumulation in the egg. We investigated whether maternal yolk corticosterone levels in Greater Rheas differ between fresh eggs collected from an intensive (IRS) and a semi-extensive (SRS) rearing system. After HPLC validation, yolk corticosterone was measured using a corticosterone 125I radio-immunoassay kit. Results (mean ± SE) showed that eggs collected from the IRS exhibited a significantly higher corticosterone concentration than eggs from SRS (89.88 ± 8.93 vs. 45.41 ± 5.48 ng/g yolk, respectively). Our findings suggest that rearing conditions under an intensive scheme (e.g., small pens with bare ground, no direct foraging and handling) might be perceived as more stressful for Greater Rhea females than semi-extensive rearing conditions (e.g., low animal density distributed in extensive areas and direct foraging), which would result in the transfer of higher yolk corticosterone levels. A better understanding of environmental conditions and female traits that affect yolk corticosterone deposition provides a background for future studies concerning the roles of maternal corticosterone on offspring development. Zoo Biol. 35:246–250, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Leche A.,National University of Cordoba | Bazzano G.,National University of Cordoba | Hansen C.,Laboratorio Of Analisis Clinicos Especializados Lace | Navarro J.L.,National University of Cordoba | And 2 more authors.
Journal of Ornithology | Year: 2014

In recent years, wild populations of Greater Rhea (Rhea americana) have declined drastically, due mainly to the conversion of grassland into cropland as a result of intensive, specialized agricultural practices. In this study we test the potential stressful effects of agricultural activities on this ratite by assessing their adrenocortical response. Specifically, we compared fecal glucocorticoid metabolite (FGM) levels of rheas living in two areas under very different land use: grasslands mainly used for cattle grazing and agro-ecosystems intensively used for crop production. Groups of rheas were observed during 45–50 min from a distance of approximately 1 km to avoid any potential disturbance. Therefore, no matching of each fecal sample with a particular sex or individual within the group was possible. Radioimmunoassay of fecal samples from 269 individuals indicated no significant differences in mean concentrations of FGM from the two habitats sampled. In the agro-ecosystem we found no overall effect of agricultural practices on the birds’ FGM levels. However, during the dry season FGM concentrations were significantly higher, which may represent a stress response to the low availability of food in the post-harvesting season. In contrast, no increase in FGM levels was registered during the dry season in the grassland, where food was available throughout the year. In this environment the highest increases in FGM levels coincided with the reproductive period, likely due to the frequent agonist encounters between males at this time of the year. Our findings, therefore, suggest that the agricultural practices have to be viewed as chronic environmental stressors for Greater Rhea populations living under such conditions. The present results support earlier research showing detrimental impacts of agricultural activities on this species, which inhabits the most productive regions of South America. © Dt. Ornithologen-Gesellschaft e.V. 2014

Leche A.,National University of Cordoba | Della Costa N.S.,National University of Cordoba | Hansen C.,Laboratorio Of Analisis Clinicos Especializados Lace | Navarro J.L.,National University of Cordoba | And 2 more authors.
Poultry Science | Year: 2013

The effect of transport stress on blood corticosterone levels in captive Greater Rheas was investigated. Twelve adult individuals (7 males; 5 fe-males) were loaded in pairs inside wooden crates and transported along a paved road for 30 min. Blood sam-ples were taken before the individuals were introduced into the crate (baseline value) and immediately after they were unloaded (30 min after capture). To assess whether corticosterone levels were affected by the blood sampling procedure per se, another 6 (nontransport) control birds (3 males; 3 females) were also captured and sampled at the same times as their transported counterparts. Plasma corticosterone concentrations were measured using a commercially available corticos-terone 125I radio-immunoassay kit. Baseline corticoste-rone levels were similar in the control and transported birds (9. 0 ± 1. 6 and 10. 4 ± 0. 8 ng/mL, respective-ly). Transportation induced a highly significant (P < 0. 001), more than 40-fold increase in the corticosterone levels (433. 6 ± 35. 4 ng/mL) that was about 5 times higher (P < 0. 001) than in their nontransported coun-terparts (88. 4 ± 14. 8 ng/mL). The present findings suggest that Greater Rhea is a species highly sensitive to stressful manipulations. Both blood sampling and transportation induced highly significant adrenocorti-cal responses. Considering that transportation is one of the unavoidable common practices in the management of Greater Rheas and, as shown in the present study, that it induces a significant 40-fold corticosterone stress response, efforts should focus on helping to generate management transport standards for optimization of the welfare of this ratite. © 2013 Poultry Science Association Inc.

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