A Molecular Biologic Study of Enterocytozoon bieneusi in HIV-Infected Patients in Lima, Peru

ABSTRACT. A cross-sectional study was conducted to examine the genotype distribution of Enterocytozoon bieneusi in HIV-infected patients who visited two government hospitals in Lima, Peru from January 2000 through March 2003. Microsporidia were detected by microscopy in 105 (3.9%) of 2,672 patients. A total of 212 stool samples from 89 microsporidia-positive patients were genotyped by sequence analysis of the internal transcribed spacer (ITS) region of the rRNA gene. A 392-bp fragment containing the complete ITS region was amplified and sequenced. Multiple alignments and phylogenetic analysis of these ITS sequences identified 11 distinct genotypes of E. bieneusi (Peru-1 to Peru-11), 6 of which were new genotypes not reported before. The remaining 5 genotypes had nucleotide sequences identical to those previously reported in humans, cats, pigs, and wild mammals. All the 11 E. bieneusi-genotypes identified are genetically related, and members of the group have been previously found in humans, domestic animals, and some wild mammals. Thus, there is a high genetic diversity of E. bieneusi in humans in Peru, and zoonotie transmission is possible if humans are in close contact with infected animals.     

Effects of diet quality on performance and nutrient regulation in an omnivorous katydid

1. Omnivores by definition eat both plants and animals. However, little is known about how diet macronutrient content affects omnivore performance, or the extent to which they can regulate macronutrient intake. We assessed these questions using the salt marsh katydid, Conocephalus spartinae Fox (Tettigoniidae). 2. In our first experiment we used artificial diets with different protein–carbohydrate ratios to assess the effects of diet quality on survival, growth, and lipid accumulation. We found that diets with a high protein–carbohydrate ratio negatively affected Conocephalus survival. Among surviving individuals growth was not significantly different across the treatments, but lipid content decreased significantly as the protein–carbohydrate ratio of diets increased. 3. In a second experiment we explored the ability of Conocephalus to regulate their protein–carbohydrate intake. Results revealed that Conocephalus did not feed randomly when presented with two nutritionally complementary foods. A detailed analysis of their protein–carbohydrate intake revealed selection for a protein‐biased diet, but a lack of tight regulate of protein–carbohydrate intake. 4. We discuss how key macronutrients can limit omnivores, and how nutritional flexibility may enable omnivores to persist in nutritionally heterogeneous environments.     

Vouchering DNA‐barcoded specimens: test of a nondestructive extraction protocol for terrestrial arthropods

Morphology‐based keys support accurate identification of many taxa. However, identification can be difficult for taxa that are either not well studied, very small, members of cryptic species complexes, or represented by immature stages. For such cases, DNA barcodes may provide diagnostic characters. Ecologists and evolutionary biologists deposit museum vouchers to document the species studied in their research. If DNA barcodes are to be used for identification, then both the DNA and the specimen from which it was extracted should be vouchered. We describe a protocol for the nondestructive extraction of DNA from terrestrial arthropods, using as examples members of the orders Acarina, Araneae, Coleoptera, Diptera, and Hymenoptera chosen to represent the ranges in size, overall sclerotization, and delicacy of key morphological characters in the group. We successfully extracted sequenceable DNA from all species after 1–4 h of immersion in extraction buffer. The extracted carcasses, processed and imaged using protocols standard for the taxon, were distinguishable from closely related species, and adequate as morphological vouchers. We provide links from the carcasses and DNA vouchers to image (MorphBank) and sequence (GenBank) databases.     

The Involvement of a Class of Cell Surface Glycoconjugates in Pseudoplasmodial Morphogenesis in Dictyostelium discoideum

Pseudoplasmodia of the cellular slime mold Dictyostelium discoideum were mechanically dissociated into cells and treated with the lectin, wheat germ agglutinin, or an antipseudoplasmodial cell antibody. Morphogenesis of the agglutinates and cell differentiation were reversibly interrupted by binding of these proteins to the cell surface. This demonstrates that one or more wheat germ agglutinin receptors and the pseudoplasmodial antigen on the cell surface of these cells play a critical role in development after aggregation.     

Differences in distribution and performance of two sap-sucking herbivores on glandular and non-glandular Datura wrightii

1. Datura wrightii Regel (Solanaceae) is polymorphic with regard to trichome type. Some plants are densely covered with short, non-glandular trichomes, whereas other plants in the same populations possess glandular trichomes that excrete a sticky exudate. The hypothesis that glandular trichomes enhance resistance to all small insect herbivores is evaluated.
2. Field censuses in four southern Californian D. wrightii plant populations revealed that glandular plants are indeed resistant to whitefly spp. (Homoptera: Aleyrodidae). Whiteflies are almost exclusively found on non-glandular plants. In contrast, Tupiocoris notatus (Distant) (Heteroptera: Miridae), another sap-sucking herbivore of similar body size, is found predominantly on plants with glandular trichomes.
3. Laboratory experiments showed that whiteflies are unable to colonize glandular D. wrightii phenotypes. After the whitefly adults had landed on the leaves of these plants, they were trapped in the exudate and died.
4. Tupiocoris notatus adults, on the other hand, laid significantly more eggs on glandular plants. The presence of the exudate was shown to be the cue that determined their choice of glandular plants.
5. In no-choice experiments, T. notatus nymphs reared on glandular plants had significantly higher survival rates and had shorter developmental periods than those raised on non-glandular plants. This, combined with the higher oviposition rates, resulted in higher T. notatus population growth rates on glandular plants than on non-glandular plants.
6. Glandular trichomes are not therefore a universal protection against small herbivores. Differences in distribution over the two plant types within the natural herbivore guild on D. wrightii may, among other selection pressures, contribute to the maintenance of the observed trichome polymorphism.     

Faecal case architecture in the gibbosus species group of Neochlamisus Karren, 1972 (Coleoptera: Chrysomelidae: Cryptocephalinae: Chlamisini)

Constructions composed of faeces are rare in insects, but occur in certain leaf-beetle clades. Members of the subfamily Cryptocephalinae share a complex behavioural and morphological synapomorphy, involving portable faecal cases that house the immature stages. A maternally initiated egg case is expanded and enlarged through four larval stadia, then sealed to provide a pupal chamber from which adults eventually emerge. We analyse and compare faecal-case architecture in ten taxa of the cryptocephaline genus Neochlamisus , and assess structural variation within a life cycle, between different 'host forms' of Neochlamisus bebbianae , and among species. These cases proved to be comprised primarily of faeces, with plant trichomes representing the only common secondary component. General architectural trends reflected variation in shape, faecal texture, and the incorporation and density of trichomes. Deviations of the Neochlamisus case from a simple geometrical gnomon reflect the changing body size of the animal, differential application of faeces, and shifts in the orientation of the carriage of the case. Neochlamisus cases are presumably energetically costly to produce, carry, and maintain, and some adaptive hypotheses of case evolution are proposed. Additionally, literature on case morphology in other camptosomates is reviewed.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 315–351.     

Devenir de la putrescine-1,4-14C chez Glycine max

Fate of Putrescine-1,4-¹⁴C in Glycine max Putrescine-1,4-¹⁴C was supplied to young decotylized Glycine max (L.) Merr. cv. Chippewa plants growing under aseptic conditions on a liquid medium with nitrogen supplied either as ammonium chloride or nitrates. Whatever the source of nitrogen the diamine was quickly transformed to γ-aminobutyric acid, succinic acid and malic acid; only a very minor part was utilized for the synthesis of polyamines. In the presence of ammonium chloride the putrescine catabolism may be slower than in the presence of nitrates. The results are explained by a weak isotopic dilution or by a diamine oxidase activity lower in “ammonium” plants than in “nitrate” plants; the two causes might co-exist. The possibility of a diamine compartmentation has to be considered.     

Predation by the Ordovician asteroid Promopalaeaster on a pelecypod

Blake, D.B. & Guensburg, T.E. 1994 10 15: Predation by the Ordovician asteroid Promopalaeaster on a pelecypod. An Ordovician Prornopalaeaster (Echinodermata: Asteroidea) wrapped about a Cuneamya? (Mol-lusca: Pelecypoda) in the extraoral feeding posture characteristic of Jurassic to modern members of the Asteriidae documents an early origin for this behavioral complex. Modern asteriids are convergent on Promopalaeastet; there is no direct phylogenetic linkage between the two. This fossil occurrence, combined with the success of modem Asteriidae, demonstrates that biological evolution and geological change need not outmode complex life habits. The fossil supports the notion of asteroids as Paleozoic-type predators, and its existence suggests that asteroids were not significant contributors to changing faunal structures in shelf seas during the Phanerozoic. Asteroidea, Pelecypoda, functional morphology, evolutionary ecology.     

Functional anatomy of the egg pore in Callosobruchus maculatus: a trade-off between gas-exchange and protective functions?

Abstract. The chorion of the egg in Callosobruchus maculatus (Coleoptera: Bruchidae) provides protection but also has to allow exchange of respiratory gases. A single opening in the chorion (the egg pore) allows diffusion of gases, and young larvae die if the egg pore is blocked. Comparison of respiration rates using a Gilson respirometer showed an increase in oxygen uptake from the first to the seventh day after the egg was laid; the increase was from 6.8 to 11.2 pl/egg/day in a Brazil strain and from 8.6 to 23.5 pl/egg/day in a Yemen strain. The Yemen strain had double the metabolic rate of Brazil-strain insects in the larvae, which are exposed to seed toxins, but not in the non-feeding adults. It is suggested that the higher metabolic rate in the Yemen larvae is related to their ability to develop in seeds that are toxic to the Brazil strain. The egg pore also differed in size and shape between the two strains. The egg pore was cylindrical in the Brazil strain, but shorter and funnel-shaped with an increased external diameter in the Yemen strain. Calculation showed that the different shape and size of the Yemen egg pore would allow a 2–3-fold increase in gas conductance compared with the Brazil strain, and this increase was consistent with the enhanced oxygen requirement of the Yemen larvae, which was a little over twice that of the Brazil larvae at 7 days. The anatomy of egg pores in Cmaculatus thus seems to represent a trade-off between two functions, allowing adequate gas exchange while maintaining the protective function of the chorion.