A Comparison of Two Brazilian Populations of Culex quinquefasciatus (Say, 1823) from Endemic and Non-endemic Areas to Infection with Wuchereria bancrofti (Cobbold, 1877)

Culex quinquefasciatus is known to be an efficient insect host of Wuchereria bancrofti. In Brazil Cx. quinquefasciatus is widely distributed throughout the country and is often abundant in and around human habitations. In contrast, Bancroftian filariasis is limited to three foci in Brazil. Experiments were undertaken to compare the vector capacities of Cx. quinquefasciatus originating from Maceió (Alagoas), one of the endemic areas of W. bancrofti infection in Brazil, and Belo Horizonte (Minas Gerais), a non endemic area. Laboratory-reared Cx. quinquefasciatus were dissected 20 days after blood feeding on microfilaraemic patients. Survival rates and the number of infective larvae that developed did not differ in female mosquitoes of different origins. Thus both populations of Culex were susceptible to infection with W. bancrofti

Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species

Size-selective fishing is expected to affect traits such as individual growth rate, but the relationship between the fishery-linked selection differentials and the corresponding phenotypic changes is not well understood. We analysed a 25-year monitoring survey of sympatric populations of the two Alpine whitefish Coregonus albellus and C. fatioi. We determined the fishing-induced selection differentials on growth rates, the actual change of growth rates over time, and potential indicators of reproductive strategies that may change over time. We found marked declines in adult growth rate and significant selection differentials that may partly explain the observed declines. However, when comparing the two sympatric species, the selection differentials on adult growth were stronger in C. albellus while the decline in adult growth rate seemed more pronounced in C. fatioi. Moreover, the selection differential on juvenile growth was significant in C. albellus but not in C. fatioi, while a significant reduction in juvenile growth over the last 25 years was only found in C. fatioi. Our results suggest that size-selective fishing affects the genetics for individual growth in these whitefish, and that the link between selection differentials and phenotypic changes is influenced by species-specific factors.

Genetic differentiation in two European tree frog (Hyla arborea) metapopulations in contrasted landscapes of Western Switzerland

The survival of threatened species as the European tree frog (Hyla arborea) is strongly dependent on the genetic variability within populations, as well as gene flow between them. In Switzerland, only two sectors in its western part still harbour metapopulations. The first is characterised by a very heterogeneous and urbanized landscape, while the second is characterised by a uninterrupted array of suitable habitats. In this study, six microsatellite loci were used to establish levels of genetic differentiation among the populations from the two different locations. The results show that the metapopulations have: (i) weak levels of genetic differentiation (FST within metapopulation ≈ 0.04), (ii) no difference in levels of genetic structuring between them, (iii) significant (p = 0.019) differences in terms of genetic diversity (Hs) and observed heterozygozity (Ho), the metapopulation located in a disturbed landscape showing lower values. Our results suggest that even if the dispersal of H. arborea among contiguous ponds seems to be efficient in areas of heterogeneous landscape, a loss of genetic diversity can occur.

Non-covalent and covalent protein labeling in two-dimensional gel electrophoresis.

Over the past decades, several sensitive post-electrophoretic stains have been developed for an identification of proteins in general, or for a specific detection of post-translational modifications such as phosphorylation, glycosylation or oxidation. Yet, for a visualization and quantification of protein differences, the differential two-dimensional gel electrophoresis, termed DIGE, has become the method of choice for a detection of differences in two sets of proteomes. The goal of this review is to evaluate the use of the most common non-covalent and covalent staining techniques in 2D electrophoresis gels, in order to obtain maximal information per electrophoresis gel and for an identification of potential biomarkers. We will also discuss the use of detergents during covalent labeling, the identification of oxidative modifications and review influence of detergents on finger prints analysis and MS/MS identification in relation to 2D electrophoresis.

The Infection Rates of Trypanosomes in Squirrel Monkeys at Two Sites in the Brazilian Amazon

A study was conducted to determine the prevalence of natural infections by trypanosome species in squirrel monkeys: Saimiri sciureus (Linnaeus) and Saimiri ustus (Geoffroy) caught respectively near 2 hydroelectric plants: Balbina, in the State of Amazonas, and Samuel, in the State of Rondônia, Brazil. A total of 165 squirrel monkeys were examined by thick and thin blood smears (BS), haemocultures and xenodiagnosis: 112 monkeys, 67.9%,(being 52.7% with mix infections) were positive to trypanosomes. Four species of trypanosomes were found in monkeys from the 2 areas: Trypanosoma (Tejeraia) rangeli Tejera or T. rangeli-like parasites in 58 squirrel monkeys (35.2%), Trypanosoma (Megatrypanum) minasense Chagas in 55 (33.3%), Trypanosoma (Herpetosoma) saimirii Rodhain or T. saimirii-like parasites in 53 (32.1%) and Trypanosoma (Schizotrypanum) cruzi Chagas in 17 (10.3%). As T. saimirii resembles T. minasense in blood-stream trypomastigotes and T. rangeli in cultural forms and in this survey almost all monkeys presenting trypanosomes morphologically indistinguishable from T. saimirii and/or T. minasense in BS were found through xenodiagnosis and/or haemoculture to be infected by T. rangeli, we suggest that the validity of T. saimirii needs to be evaluated

Anopheles aquasalis Eggs from Two Venezuelan Localities Compared by Scanning Electron Microscopy

Anopheles (Nyssorhynchus) aquasalis, is the main coastal vector of malaria from northeastern Venezuela to southeastern Brazil. Several authors have argued that An. aquasalis is a highly polymorphic species while others indicated that it is a complex of closely related species. This investigation compared the morphology of An. aquasalis eggs from Sinamaica (Zulia State) and Yaguaraparo (Sucre State), the west and east of Venezuela, respectively. We were able to separate eggs from the two localities using discriminant analyses based on ratios and percentages of anterior and posterior tubercles measured by scanning electron microscopy. The results of this work suggest that An. aquasalis has high intraspecific variation

Evolutionary and convergence stability for continuous phenotypes in finite populations derived from two-allele models.

The evolution of a quantitative phenotype is often envisioned as a trait substitution sequence where mutant alleles repeatedly replace resident ones. In infinite populations, the invasion fitness of a mutant in this two-allele representation of the evolutionary process is used to characterize features about long-term phenotypic evolution, such as singular points, convergence stability (established from first-order effects of selection), branching points, and evolutionary stability (established from second-order effects of selection). Here, we try to characterize long-term phenotypic evolution in finite populations from this two-allele representation of the evolutionary process. We construct a stochastic model describing evolutionary dynamics at non-rare mutant allele frequency. We then derive stability conditions based on stationary average mutant frequencies in the presence of vanishing mutation rates. We find that the second-order stability condition obtained from second-order effects of selection is identical to convergence stability. Thus, in two-allele systems in finite populations, convergence stability is enough to characterize long-term evolution under the trait substitution sequence assumption. We perform individual-based simulations to confirm our analytic results.

Comparison between Two Methods for Diagnosis of Trichinellosis: Trichinoscopy and Artificial Digestion

Two direct methods for the diagnosis of trichinellosis were compared: trichinoscopy and artificial digestion. Muscles from 17 wistar rats, orally infected with 500 Trichinella spiralis encysted larvae were examined. From each of the following muscles: diaphragm, tongue, masseters, intercostals, triceps brachialis and cuadriceps femoralis, 648,440 larvae from 1 g samples were recovered. The linear correlation between trichinoscopy and artificial digestion was very high and significant (r=0.94, p< 0.0001), showing that both methods for the detection of muscular larvae did not differ significantly. In both methods, significant differences were found in the distribution of larvae per gramme of muscle

A two-compartment mathematical model of neuroglial metabolism using [1-(11)C] acetate.

The purpose of this study was to develop a two-compartment metabolic model of brain metabolism to assess oxidative metabolism from [1-(11)C] acetate radiotracer experiments, using an approach previously applied in (13)C magnetic resonance spectroscopy (MRS), and compared with an one-tissue compartment model previously used in brain [1-(11)C] acetate studies. Compared with (13)C MRS studies, (11)C radiotracer measurements provide a single uptake curve representing the sum of all labeled metabolites, without chemical differentiation, but with higher temporal resolution. The reliability of the adjusted metabolic fluxes was analyzed with Monte-Carlo simulations using synthetic (11)C uptake curves, based on a typical arterial input function and previously published values of the neuroglial fluxes V(tca)(g), V(x), V(nt), and V(tca)(n) measured in dynamic (13)C MRS experiments. Assuming V(x)(g)=10 × V(tca)(g) and V(x)(n)=V(tca)(n), it was possible to assess the composite glial tricarboxylic acid (TCA) cycle flux V(gt)(g) (V(gt)(g)=V(x)(g) × V(tca)(g)/(V(x)(g)+V(tca)(g))) and the neurotransmission flux V(nt) from (11)C tissue-activity curves obtained within 30 minutes in the rat cortex with a beta-probe after a bolus infusion of [1-(11)C] acetate (n=9), resulting in V(gt)(g)=0.136±0.042 and V(nt)=0.170±0.103 μmol/g per minute (mean±s.d. of the group), in good agreement with (13)C MRS measurements.

Two monoclonal rat antibodies with specificity for the beta-chain variable region V beta 6 of the murine T-cell receptor.

Two rat monoclonal antibodies (mAbs), 44-22-1 and 46-6B5, which recognize an alloreactive cytotoxic clone, 3F9, have been further tested on a panel of T hybridomas and cytotoxic T-cell clones for binding and functional activities. The mAbs recognized only those cells sharing the expression of the T-cell receptor beta-chain variable region gene V beta 6 with 3F9. All V beta 6+ cells were activated by these mAbs under cross-linking conditions and their antigen-specific activation was blocked by soluble mAb. Furthermore, depletion of 46-6B5+ normal lymph node T cells eliminated all cells expressing the epitope recognized by 44-22-1 and V beta 6 mRNA.

A Redescription of Riggia paranensis Szidat, 1948 (Isopoda, Cymothoidae) Based on Thirty-two Specimens from Curimatid Fish of Rio de Janeiro, Brazil, with an Emendation of the Genus

Riggia paranensis Szidat, 1948 is redescribed on the basis of 30 female and 2 male specimens collected from the pericardial cavities of the curimatid fish Cyphocarax (= Curimata) gilberti (Quoy & Gaimard). The fishes were caught in the Itabapoana River, State of Rio de Janeiro, southeastern Brazil. The presence of" dwarf" males, as reported by Szidat, was verified. The fusion of the pleonites and pleotelson in adult females was also confirmed. The generic diagnosis was emended to include details of the mouthparts and pleopods

Participation of interleukin-5, interleukin-8 and leukotriene B4 in eosinophil accumulation in two different experimental models

There are several experimental models describing in vivo eosinophil (EO) migration, including ip injection of a large volume of saline (SAL) or Sephadex beads (SEP). The aim of this study was to investigate the mechanisms involved in the EO migration in these two models. Two consecutive injections of SAL given 48 hr apart, induced a selective recruitment of EO into peritoneal cavity of rats, which peaked 48 hr after the last injection. SEP, when injected ip, promoted EO accumulation in rats. The phenomenom was dose-related and peaked 48 hr after SEP injection. To investigate the mediators involved in this process we showed that BW A4C, MK 886 and dexamethasone (DXA) inhibited the EO migration induced by SAL and SEP. To investigate the source of the EO chemotactic factor we showed that mast cells, macrophages (MO), but not lymphocytes, incubated in vitro in presence of SAL released a factor which induced EO migration. With SEP, only mast cells release a factor that induced EO migration, which was inhibited by BW A4C, MK 886 and DXA. Furthermore, the chemotactic activity of SAL-stimulated mast cells was inhibited by antisera against IL-5 and IL-8 (interleukin). SAL-stimulated MO were only inhibited by anti-IL-8 antibodies as well SEP-stimulated mast cells. These results suggest that the EO migration induced by SAL may be dependent on resident mast cells and MO and mediated by LTB4, IL-5 and IL-8. SEP-induced EO migration was dependent on mast cells and may be mediated by LTB4 and IL-8. Furthermore, IL-5 and IL-8 induced EO migration, which was also dependent on resident cells and mediated by LTB4 . In conclusion, EO migration induced by SAL is dependent on mast cells and MO, whereas that induced by SEP is dependent on mast cells alone. Stimulated mast cells release LTB4, IL-5 and IL-8 while MO release LTB4 and IL-8. The IL-5 and IL-8 release by the SAL or SEP-stimulated resident cells may act in an autocrine fashion, thus potentiating LTB4 release.

Mendacastrum n. gen. and Domuzdagia n. gen., two Jurassic spherical Spumellaria (Radiolaria) with hagiastrid medullary shell

Two new spumellarian radiolarian genera, Mendacastrum and Domuzdagia, are described from the lower Tithonian and lower Pliensbachian respectively. Both have a spherical cortical shell of actinommid type and a spherical or subspherical double medullary shell with the inner medullary shell of hagiastrid s.l. type. The inner medullary shell of Mendacastrum is of dactyliosphaerid or higumastrid s. sit. type, whereas that of Domuzdagia is of angulobracchiid type. Since they cannot be assigned to any described Mesozoic pyloniacean families, they are considered as type genera of two new families: Mendacastridae and Domuzdagiidae respectively.