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  • Author: M. Carvalhaes x
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Lagochilascaris minor: Specific antibodies are related with resistance to experimental infection in A/J strain of mice

Abstract

Lagochilascaris minor is the causative agent of human lagochilascariosis, a disease that affects the neck region causing abscesses with eggs, adult parasites and L3/L4 larvae within purulent exudates. Nowadays, mice are considered intermediary hosts for the parasite. In previous study we observed that A/J mice experimentally infected with Lagochilascaris minor showed higher survival ratios than B10.A mice. Now, we denoted that A/J mice (resistant to experimental infection) produced higher levels of IgM, IgG and IgA against the crude extract (excepted for IgM) and secreted/excreted antigens of the parasite; on the other hand, B10.A mice (susceptible to experimental infection) produced higher levels of IgE in the later period of the experimental infection than A/J infected mice.

Open access
Influence of the genetic pattern and sex of mice in experimental lagochilascariosis

Abstract

We studied experimental lagochilascariosis in male and female mice of four strains. The survival ratio and number of larvae recovered varied: B10.A and C57BL/6 mice had the highest number of larvae 90 days after infection and the lowest survival ratio at 345 days of infection. BALB/c mice had an intermediate survival ratio and number of larvae. A/J mice had the lowest number of larvae and the highest survival ratio. Our findings suggest that resistance to Lagochilascaris minor is not linked to the H-2a region because both susceptible B10.A and resistant A/J mice express the H-2a haplotype. However, the pattern of mortality and larvae recovered that we observed in C57BL/6 mice, which possess the same genetic background as B10.A, indicates that the background genotype does affect the outcome of lagochilascariosis in mice. This study demonstrates that the genetic background, but not H-2a or sex, determine the outcome of lagochilascariosis in mice.

Open access
The X-chromosome-linked immunodeficiency determines an improved course of murine lagochilascariosis

Abstract

Lagochilascaris minor is the causative agent of lagochilascariosis, a disease that affects the neck region causing exudative abscesses with eggs, adult parasites and L3/L4 larvae within purulent exudates. Nowadays, mice are considered intermediate hosts for the parasite. To determine the pattern of infection in B1 cell-defective mice, experimental lagochilascariosis was studied in BALB/c and X-chromosome-linked immunodeficient (Xid) mice. BALB.xid infected mice showed higher survival ratios and less intense lung lesions than BALB/c mice. Serum levels of IL-10 was higher in BALB/c infected mice when compared to BALB.xid animals; however, serum levels of IFNγ, in control and infected BALB.xid mice, were statistically different from that seen in BALB/c mice. We discuss the participation of B1 cells and their cytokines in the resistance to infection.

Open access
Genetic diversity and spatial genetic structure in populations of Orbignya phalerata Mart. under different exploitation intensities in the Brazilian savanna

Abstract

Genetic studies in tropical tree species have found signs of decreased genetic diversity and increased levels of inbreeding and spatial genetic structure (SGS) in fragmented and exploited populations. The aim of this paper was to investigate genetic diversity, structure, and intrapopulation SGS using eight microsatellite loci for three Orbignya phalerata populations that have undergone different intensities of seed harvesting. From each population, we georeferenced and sampled 30 seedlings, 30 juveniles, and 30 adult trees. The total number of alleles over all loci (k), and observed (Ho) and expected heterozygosity (He) presented lower values for the population experiencing more intense fruit harvesting than less heavily exploited populations, suggesting that fruit harvesting may decrease genetic diversity. Null alleles were detected in practically all loci among seedlings, juveniles, and adults in all populations, indicating that the estimates of Ho, He, and fixation index (F) are biased. When corrected for null alleles (FNull), the fixation index decreased for all samples, resulting in significantly higher than zero results for seedlings of all populations, but not for juveniles and adults of all populations. The comparison of FNull values between cohorts in the most heavily exploited population (ESP) suggests that inbred individuals are eliminated between seedling and adult stages. Significant SGS was detected up to 60 m in all populations, which indicates short distance seed dispersal. Genetic differentiation (G’ST) between pairwise populations was related to spatial distance between populations, with the greatest difference between more distant populations.

Open access