C3 allotypes in pregnancy hypertension and eclampsia

C3 allotyping has been performed on 424 Australian women, 203 with normotensive pregnancies, 161 with hypertensive noneclamptic pregnancies and 60 eclamptic women. The frequency of women heterozygous for 'rare' C3 alleles was 1% in the normotensive women and 3.7% in the hypertensive group. Three out of 25 (12%) of the women with proteinuric hypertension in pregnancy carried 'rare' C3 alleles. This suggested the hypothesis that pre-eclampsia/eclampsia is associated with a higher frequency of rare alleles. The sample of 60 eclamptic women collected to test the hypothesis had no rare alleles, refuting the hypothesis. The frequency of the common (C3F, C3S) alleles did not differ significantly between the three groups. We conclude that there is no evidence for any association between susceptibility to eclampsia and allotypes of the C3 complement component.     

Population differences in larval hostplant use in the checkerspot butterfly, Euphydryas chalcedona

Larvae from two populations of Euphydryas chalcedona Doubleday & Hewitson (Nymphalidae) were reared on their own hostplant and that of the other population, in both pre-diapause and post-diapause instars. One population, Chico, uses Penstemon breviflorus Lindl. (Scrophulariaceae), and the other, Echo Lake, uses P. newberryi Gray. Growth rate and survival were determined for pre-diapause and post-diapause larvae from both populations on both plant species; and digestive efficiencies were calculated during the prediapause instars. The results showed that larvae from the two populations differed in their responses to the two plant species. Pre-diapause larvae from Chico performed equally well on both plant species—survival and digestive indices were not significantly different for two Penstemon species. In contrast, pre-diapause larvae from Echo Lake performed significantly worse on the non-hostplant—growth and survival were significantly lower on the non-host, P. breviflorus. In addition, comparison of digestive efficiencies for the two plants showed that larvae from Echo Lake digested P. breviflorus better than P. newberryi, but were significantly less able to convert P. breviflorus to body mass. In the post-diapause instars, larvae from Chico grew faster on the host than on the non-host. Larvae from Echo Lake grew quite slowly on both plant species and significantly more of the Echo Lake larvae returned to diapause instead of completing development.

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Résumé Des chenilles de deux populations d'E. chalcedona ont été élevées sur leur propre plante-hôte et sur celle de l'autre population, aux stades avant et après diapause. Les deux populations s'alimentent sur différentes espèces de Penstemon (Scrophulariaceae), et une population—Echo Lake—est monophage sur P. newberry, tandis que l'autre—Chico—utilise d'abord P. breviflorus, mais les chenilles après diapause sont trouvées sur au moins deux autres espèces de plantes. Les taux de croissance et de survie ont été déterminés pour des chenilles avant et après diapause pour les deux populations sur les deux plantes; les efficacités digestives ont été calculées sur les chenilles avant diapause.Les résultats ont montré que les chenilles des deux populations différaient par leur degré de spécialisation digestive sur leur plante hôte normale: les chenilles de Chico ont utilisé aussi bien les deux plantes, tandis que celles d'Echo Lake le faisaient significativement moins bien sur la plante non-hôte, par suite de l'inaptitude à la digérer. Ainsi la population oligophage est alimentairement moins spécialisée et plus capable de se débrouiller avec une plante non-hôte. Après diapause, les chenilles de Chico s'alimentaient significativement mieux sur plante hôte que non-hôte, ce qui était le cas aussi pour la population monophage. Dans l'ensemble, les chenilles de la population monophage semblaient moins capables de se débrouiller dans des conditions défavorables ou moins avantageuses.

     

Survey for mitochondrial-desmosome complexes in differentiating epithelia

Summary Mitochondria are frequently found to be closely associated with the plaques of desmosomes in a variety of columnar or cuboidal epithelia of fetal or early postnatal mammals (mouse, rat, human being). The organs in which mitochondrial-desmosome complexes were found include stomach, small intestine, pancreas, kidney, epididymis, seminal vesicle, coagulating gland, thyroid gland. The association has not been observed in simple squamous epithelium (vascular endothelium). Mitochondria lie quite close to desmosomes in the stratum spinosum of stratified squamous mucous epithelium of fetal animals and also to axo-dendritic synapses in still poorly differentiated central nervous system. Mitochondria have also been detected close to attachment sites in ectoderm of the early frog gastrulae. Here there is as yet no visible plaque material.We suggest that the mitochondria may provide energy or some chemical for the formation of the plaque. This hypothesis does not explain why the complexes are not found in poorly differentiated epithelia from older animals.Dedicated to Professor Berta V. Scharrer on her 60th birthday, with affection and admiration. — This study was supported by U.S.P.H.S. research grants NB-05219 and GM-10757 from the National Institutes of Health.     

Nucleotide sequence of the Vibrio alginolyticus calcium-dependent, detergent-resistant alkaline serine exoprotease A

The nucleotide sequence of the Vibrio alginolyticus alkaline serine exoprotease A (ProA) gene cloned in Escherichia coli was determined. The exoprotease A gene (proA) consisted of 1602 bp which encoded a protein of 534 amino acids (aa) with an Mr of 55,900. The region upstream from the gene was characterized by a putative promoter consensus region (-10 -35), a ribosome-binding site and ATG start codon. The proA gene encodes a typical 21-aa N-terminal signal sequence which, when fused to alkaline phosphatase by means of transposon TnphoA, was able to mediate transport of the alkaline phosphatase to the periplasm in E. coli. Deletions of up to 106 aa from the C terminus of ProA did not result in the loss of extracellular protease activity. Additional V. alginolyticus genes were not involved in the secretion into the medium of the cloned ProA in E. coli. The amino acid sequence of ProA showed low overall homology to a Serratia marcescens serine exoprotease but significant homology was detected with other subtilisin family exoproteases. The fungal proteinase K, another sodium dodecyl sulfate-resistant protease, had 44% aa homology with ProA.     

USE OF BIOELECTRICAL IMPEDANCE ANALYSIS TO ASSESS BODY COMPOSITION OF SEALS

Abstract: Bioelectrical impedance analysis (BIA) measures resistance and reactance of a current as it passes through an organism. The validity of using BIA as a tool to measure body water content, and hence body composition and condition, was tested on harp and ringed seals. The resistance and reactance readings from BIA were compared to estimates of total body water (TBW) determined via tritiated water dilution. The relationship between resistance and TBW (% of body mass) was linear after logarithmic transformation and the two variables were highly correlated. We describe the electrode configuration and placements which provide reliable results in these seals. Our findings indicate that BIA has considerable potential as an inexpensive, rapid, and reliable technique for estimating body composition of phocid seals.     

Presence of predatory wasps and stinkbugs alters foraging behavior of cryptic and non-cryptic caterpillars on plantain (Plantago lanceolata)

We examined the foraging patterns of two species of caterpillar (Junonia coenia: Nymphalidae and Spilosoma congrua: Arctiidae) that contrast in feeding specialization and crypticity on plantain (Plantago lanceolata) in the absence and presence of two different insect predators [stinkbugs, Podisus maculiventris (Pentatomidae) and wasps, Polistes fuscatus (Vespidae)]. Junonia larvae were quite apparent to human observers, feeding on upper leaf surfaces during daylight, whereas Spilosoma larvae were relatively cryptic, often hiding under leaves and in soil crevices during daylight. In the presence of either predator species, the non-cryptic Junonia caterpillars more quickly left the plant on which they were initially placed and were less apparent than Junonia larvae not exposed to predators. The presence of predators had no detectable influence on where the caterpillars occurred on the plants (new, intermediate-aged or mature leaves, or reproductive stalks). Surprisingly, the predators influenced the behavior of the inherently cryptic Spilosoma: the apparency of these larvae at night increased when wasps had access to the plots during the day. Survivorship of the non-cryptic Junonia was less than 12% when stinkbugs were present compared to 60% in their absence. Although the presence of wasps resulted in a lower relative growth rate for the non-cryptic Junonia larvae, the indirect effect of predators on reduction in survivorship due to alterations in prey growth rate through behavioral changes was less than 3%. After taking into account the decline in caterpillars per plot through predation, we found that both the amount of leaves eaten and the proportion of plants eaten were altered on plots with predators present, which suggests that the caterpillars' increased consumption countered increased maintenance costs due to the presence of predators. Overall, our results indicate that hostplant size, level of predation and type of predator can influence the degree to which these caterpillars react to the presence of insect predators. In contrast, degree of inherent feeding specialization and cryptic behavior seemed to have little effect on the expression of reactive behaviors of these caterpillars to predators.     

Trypanosoma cruzi: strain selection by different schedules of mouse passage of an initially mixed infection

From an initial double infection in mice, established by simultaneous and equivalent inocula of bloodstream forms of strains Y and F of Trypanosoma cruzi, two lines were derived by subinoculations: one (W) passaged every week, the other (M) every month. Through biological and biochemical methods only the Y strain was identified at the end of the 10th and 16th passages of line W and only the F strain at the 2nd and 4th passages of line M. The results illustrate strain selection through laboratory manipulation of initially mixed populations of T. cruzi.