Opportunistic or selective? Stage-dependent feeding behavior in a wild vector of Chagas disease.

The composition and contribution of different host species in the dynamics of vector-borne zoonotic parasites are particularly relevant for public health. Hence, the study of host selection by vectors is fundamental. Developmental stage and infection status are factors that may modulate vector feeding behavior. In the semi-arid Mediterranean ecosystem of South America, the transmission of Trypanosoma cruzi, the protozoan causing Chagas disease, includes the triatomine vector Mepraia spinolai and several vertebrate species. In this field study, we examined whether M. spinolai exhibits an opportunistic feeding behavior dependent upon developmental stage and/or infection status. We found that M. spinolai does not feed according to the relative availability of vertebrate species. In addition, early stage nymphs (first/second instars) fed on twice as many different species as middle (third/fourth instars) and late (fifth instars and adults) M. spinolai, with the former feeding on native rodents and lizards and the latter mostly on rabbits. Infected and uninfected M. spinolai showed similar feeding profiles. Wild triatomine species might be described as stage-dependent selective blood feeders, as a consequence of the temporal and spatial scale at which host-vector interactions occur, highlighting that all developmental stages might be infected and capable of transmitting T. cruzi.

Basic and applied features in the cryopreservation progress of bovine embryos.

The expansion of the use of in vitro production techniques has revolutionized the bovine embryo market. In the last decade, we have seen the number of in vitro produced (IVP) embryos surpass the number of in vivo-derived (IVD) embryos obtained worldwide. Concomitantly, other biotechnologies were also improved, following the global trend. Embryo cryopreservation has received special attention, as it is one of the tools capable of disseminating in vitro production. Currently, two protocols are available: slow freezing and vitrification. Both have advantages and disadvantages regarding their application and, many aspects need to be considered before their use. In this review, we discuss in vitro production market trends, cellular and molecular features involved in embryo response to cryopreservation, and addressed cryo-storage period and embryonic developmental stage on cryosurvival. In addition, we also presented an overview of some aspects that impact the pregnancy rate following transfer of fresh and cryopreserved IVP embryos.

Chemotaxonomic Profile and Intraspecific Variation in the Blow Fly of Forensic Interest Chrysomya megacephala (Diptera: Calliphoridae).

Necrophagous insects such as blow flies (Diptera: Calliphoridae) are considered crucial in forensic entomology. Identification at species level and determination of larval stage are the basis for estimation of postmortem interval (PMI). Insect evidence can also be used in the determination of crime scenes, since body displacement is common. The aim of this study was to determine the chemotaxonomic profile and intraspecific variability of the forensically important blow fly Chrysomya megacephala (F. 1794). Adults were collected in the municipalities of Dourados-MS (Brazil) and Rio Claro-SP (Brazil), and then transferred to the laboratory for oviposition and development of the immature stages. Chemical analysis of cuticular compounds was performed by gas chromatography. Cuticular chemical profiles varied significantly between the two populations, as well as between developmental stages, supporting the use of these compounds as a complementary tool to help identify the species and its stages, along with geographical variability. This could greatly accelerate forensic investigations, eliminating the need to allow the fly larvae to develop until adult stage in order to confirm the species identity and sample origin.

Protein undernutrition during development and oxidative impairment in the central nervous system (CNS): potential factors in the occurrence of metabolic syndrome and CNS disease.

Mitochondria play a regulatory role in several essential cell processes including cell metabolism, calcium balance and cell viability. In recent years, it has been postulated that mitochondria participate in the pathogenesis of a number of chronic diseases, including central nervous system disorders. Thus, the concept of mitochondrial function now extends far beyond the common view of this organelle as the 'powerhouse' of the cell to a new appreciation of the mitochondrion as a transducer of early metabolic insult into chronic disease in later life. In this review, we have attempted to describe some of the associations between nutritional status and mitochondrial function (and dysfunction) during embryonic development with the occurrence of neural oxidative imbalance and neurogenic disease in adulthood.

Corpus luteum diameter and embryo developmental stage are associated with pregnancy rate: data analysis from 17, 521 embryo transfer s from a commercial in vitro bovine embryo production program

The objective of th is study was to assess the association between CL diameter , embryo developmental status and recipient pregnancy rate after in vitro - produced embryo transfer. Data from a total of 17 , 521 embryo transfer s from a commercial program were analyzed. The information was organized in pivot tables and the frequency of variables was determined with contingency tables. Additionally, a logistic regression analysis was performed to determine the o dds ratio and the degree of association between the variables. Higher pregnancy rates were achieved when the CL was larger than 24 mm (39.7%) and 22 mm (33.7 %) in diameter , whereas lower pregnancy rates were associated with a CL of 14 mm ( 24.2 %). Moreover, pregnancy rate was 30.5% when the recipients had a CL greater than 20 mm in diameter , whereas pregnancy rate was 32.0% with a CL smaller than 20 mm (P ˂ 0.01). Furthermore, an association between high conception rate s and CL diameter was found. With regard to embryo developmental status , higher pregnancy rates were associated with expanded blastocyst (37.0 %) and blastocyst (28.8%) transfer. Low pregnancy rates were achieved when morula e were transferred (15.4%). The present results suggest that variables such as CL diameter and embryo developmental status are significantly important and must be considered for the success of an in vitro - produced bovine embryo transfer program.

Corpus luteum diameter and embryo developmental stage are associated with pregnancy rate: data analysis from 17, 521 embryo transfer s from a commercial in vitro bovine embryo production program

The objective of th is study was to assess the association between CL diameter , embryo developmental status and recipient pregnancy rate after in vitro - produced embryo transfer. Data from a total of 17 , 521 embryo transfer s from a commercial program were analyzed. The information was organized in pivot tables and the frequency of variables was determined with contingency tables. Additionally, a logistic regression analysis was performed to determine the o dds ratio and the degree of association between the variables. Higher pregnancy rates were achieved when the CL was larger than 24 mm (39.7%) and 22 mm (33.7 %) in diameter , whereas lower pregnancy rates were associated with a CL of 14 mm ( 24.2 %). Moreover, pregnancy rate was 30.5% when the recipients had a CL greater than 20 mm in diameter , whereas pregnancy rate was 32.0% with a CL smaller than 20 mm (P ˂ 0.01). Furthermore, an association between high conception rate s and CL diameter was found. With regard to embryo developmental status , higher pregnancy rates were associated with expanded blastocyst (37.0 %) and blastocyst (28.8%) transfer. Low pregnancy rates were achieved when morula e were transferred (15.4%). The present results suggest that variables such as CL diameter and embryo developmental status are significantly important and must be considered for the success of an in vitro - produced bovine embryo transfer program.(AU)