DNA Fingerprinting of Trypanosoma vivax Isolates Rapidly Identifies Intraspecific Relationships

ABSTRACT. Using the polymerase chain reaction and arbitrarily selected oligonucleotide primers of 10 or 11 bases, we have amplified DNA sequences from Trypanosoma vivax parasites isolated from South America and Africa. On the basis of polymorphisms in the DNA fingerprints generated by three of the primers, the parasites could be separated into two major groups, one comprising T. vivax isolates from Kenya and the second including all the other T. vivax parasites (from Colombia, The Gambia, Nigeria and Uganda). One of these three primers (ILo 525) also gave isolate-specific DNA fingerprints for the parasites for the parasites tested, which will allow the use of this technique both in the species identification and discrimination of T. vivax parasites.     

Surface proteins on Cloudman melanoma cells

Lactoperoxidase-catalyzed cell surface radioiodination was used to study the size distribution and physiological characteristics of cell surface proteins of Cloudman melanoma cells maintained in vivo (An cell) or in vitro (TC cells). Slight qualitative and quantitative differences were observed between detergent-extracted radiolabeled membrane proteins obtained from An and TC cells when the proteins were resolved by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Striking differences were observed in the membrane residence times of radioiodinated proteins of the An and TC cells when labeled cells were cultured 24 hr. Many labeled surface proteins are lost more rapidly from An cells than from TC cells. The possibility that the release of surface proteins from tumor cell membranes may be an important factor which determines the nature of the host immune response against incipient cancers is considered.     

Estimation of Detection Probability in Manatee Aerial Surveys at a Winter Aggregation Site

Abstract: Estimating components of detection probability is crucial to improving the design of aerial surveys for wildlife populations, and this is especially true for species of marine mammals that are threatened or endangered. To evaluate the probability that Florida manatees (Trichechus manatus latirostris) will be detected by observers during aerial surveys, we conducted 6 series of survey flights, during mornings and afternoons on 14-16 consecutive days over the Tampa Electric Company's (TECO) Big Bend power plant discharge canal in Tampa Bay, Florida, USA (winter 2000 through 2003). Our objective was to understand how our ability to detect manatees at a winter aggregation site affects aerial survey counts, so that we may improve techniques for estimating manatee population size. We estimated the probability that manatees would be present at the warm-water discharge of the plant during winter cold fronts and estimated the overall detection probability of manatees present at the plant and the 2 components that make up the probability of detection (the probability of being available and the probability of being detected given they are available). We used telemetry tags and marker flags (n = 15) to facilitate capture-recapture analyses. The probability that marked manatees would be at the plant varied from 48% to 68% across flight series and was inversely related to the ambient water temperature. Based on sightings of marked animals, estimates of the overall probability of detecting a manatee ranged from 45% to 69% across flight series (x̄ = 58%, n = 6). The probability that a manatee would be available to an observer ranged from 73% to 94% across flight series (x̄ = 83%) but was constant among years (83%, 81%, and 78%; x̄ = 81%). The probability that an available manatee would be detected by an aerial observer was variable across flight series (55-95%) and years (73%, 86%, and 66%, x̄ = 73%). Independent estimates of the probability that a manatee would be available to the observer on one pass were obtained from time-depth data loggers and ranged from 5% to 33% (x̄ = 19%, SE = 3.7%), and the probability that a manatee would be available during ≥1 of 10 passes ranged from 41% to 98% (x̄ = 88%, 95% confidence bounds 0.71-0.95). We adjusted survey counts using measures of detectability. Although corrected counts presented here are site-specific, adjusting counts based on detection probability will greatly improve reliability of population estimates from all aerial surveys. Special sampling to estimate components of detection probability should be built into all aerial surveys to ensure that reliable and unbiased information on species abundance is used to evaluate wildlife populations.     

Origins and relationships of the Pleuronectoidei: Molecular and morphological analysis of living and fossil taxa

Flatfishes (Pleuronectiformes) are a species‐rich and distinct group of fishes characterized by cranial asymmetry. Flatfishes occupy a wide diversity of habitats, including the tropical deep‐sea and freshwaters, and often are small‐bodied fishes. Most scientific effort, however, has been focused on large‐bodied temperate marine species important in fisheries. Phylogenetic study of flatfishes has also long been limited in scope and focused on the placement and monophyly of flatfishes. As a result, several questions in systematic biology have persisted that molecular phylogenetic study can answer. We examine the Pleuronectoidei, the largest suborder of Pleuronectiformes with >99% of species diversity of the order, in detail with a multilocus nuclear and mitochondrial data set of 57 pleuronectoids from 13 families covering a wide range of habitats. We combine the molecular data with a morphological matrix to construct a total evidence phylogeny that places fossil flatfishes among extant lineages. Utilizing a time‐calibrated phylogeny, we examine the timing of diversification, area of origin and ancestral temperature preference of Pleuronectoidei. We find polyphyly or paraphyly of two flatfish families, the Paralichthyidae and the Rhombosoleidae, and support the creation of two additional families—Cyclopsettidae and Oncopteridae—to resolve their non‐monophyletic status. Our findings also support the distinctiveness of Paralichthodidae and refine the placement of that lineage. Despite a core fossil record in Europe, the observed recent diversity of pleuronectoids in the Indo‐West Pacific is most likely a result of the Indo‐West Pacific being the area of origin for pleuronectoids and the ancestral temperature preference of flatfishes is most likely tropical.     

Avian research in the Caribbean: past contributions and current priorities

ABSTRACT The islands of the Caribbean contain habitat of critical importance to a large number of endemic and resident birds, as well as many overwintering Neotropical migrants, and they rank as a globally outstanding conservation priority ecoregion and biodiversity hotspot. Considerable research from the region has focused on the ecology of permanent resident species, and these studies have had particular significance for threatened species management, especially parrot biology and conservation, but also for tropical community ecology in general. Work by ornithologists in the Caribbean has been instrumental in improving our understanding of the ecology of overwintering Neotropical migrants and in developing long‐term monitoring programs. Although Caribbean‐based studies of birds have resulted in significant contributions in many important areas of ecological research, there is a great need for additional research. Especially needed are studies with application to the management of resident species, and studies of how bird populations may be affected by pathogens, parasites, plants, and other types of biotic interactions. Studies focusing on how bird species and populations are affected by global climate change, and cumulative, landscape‐level changes in land use are also needed. Along with additional research, scientists have an important role to play in building capacity to prepare the next generation of biologists in the region who will need to address mounting challenges related to biodiversity protection. As with many conservation efforts, funding is a critical need for almost all organizations and agencies involved in research, conservation action, and capacity building in the West Indies.     

New evidence for the potential role of Culex pipiens mosquitoes in the transmission cycle of West Nile virus in Tunisia

Physiological and molecular characteristics of natural populations of Culex pipiens Linnaeus, 1758 (Diptera: Culicidae) were investigated to elucidate how this species is potentially involved in the transmission of West Nile virus in Tunisia. A total of 215 Cx. pipiens females from 11 breeding habitats were analysed in the laboratory to estimate autogeny and stenogamy rates. They were tested individually for the locus CQ11 to distinguish between the two Cx. pipiens forms, pipiens and molestus. All tested Cx. pipiens populations were stenogamous. Females from underground breeding sites were all autogeneous, whereas females from above‐ground habitats were mostly anautogeneous. Of all the females tested, 59.7% were identified as pipiens, 22.4% as molestus, and 17.9% as hybrid pipiens/molestus. Furthermore, both Cx. pipiens forms and their hybrids were found to co‐occur in sympatry in all sites. The results of this study represent the first evidence that both Cx. pipiens forms and their hybrids are present in Tunisia. Because hybrids able to act as bridge vectors are present in all studied habitats, Tunisia can be considered to have a high degree of receptivity for the establishment of West Nile virus zoonotic cycles.     

Avian defensive behavior and blood-feeding success of the West Nile vector mosquito, Culex pipiens

Avian defensive behavior against host-seeking arthropods influencestransmission of vector-borne pathogens by affecting mosquitobiting rate, either by preventing vector–host contactor by increasing the rate of multiple host feeding. We exposedhouse sparrows (Passer domesticus L.) and chickens (Gallus gallusdomesticus L.) to Culex pipiens pipiens L. overnight in a largeobservation cage and measured avian defensive behavior ratesand mosquito blood-feeding success. Both bird species exhibiteda range of defensive behaviors, 90% of which were foot stomps,head movements, and wing shakes. Total behavior rates increasedproportionately with mosquito density in both species, increasedafter the first hour of mosquito exposure, and decreased asindividual birds were exposed to mosquitoes multiple times.Mosquito blood-feeding success on house sparrows was high overall(82 ± 5%) and independent of behavior rates. Blood-feedingsuccess on chicks was lower (58 ± 5%) and negativelycorrelated with defensive behavior rate after the first hourof mosquito exposure. Results revealed a higher percentage ofpartial blood meals on chicks (18 ± 3% of all blood mealson chicks) than on house sparrows (4.9 ± 3%). Birds ofboth species ate an average of 9.4 ± 1.2% of mosquitoes,and this percentage was positively correlated with defensivebehavior. High mosquito feeding success on house sparrows supportsits role as a potential amplifying host of West Nile virus.     

Virus-specific proliferative T-cell responses: Parameters and specificity

The genetic requirements for inducing virus-specific T-cell proliferation were investigated by taking spleen cells from animals primed with vaccinia virus in vivo, then culturing the cells in vitro with vaccinia virus-infected syngeneic peritoneal macrophages, and finally restimulating these cells a second time in vitro with vaccinia virus-infected macrophages from several strains of mice. Under these conditions, T cells proliferated in the tertiary response to virus-specific stimulation, whereas background proliferation caused by allogeneic differences between stimulator and responder cells was minimal. Compatibility between T cells and infected stimulator cells at the K or I regions alone or at I-A or I-A + I-B regions of the major histocompatibility complex (MHC) produced strong proliferative responses, whereas compatibility at D alone often resulted in somewhat weaker responses. However, these responses were rarely as great as in combinations of completely syngeneic stimulator and responder cells. Homology between responding and virus-infected stimulating cells in more than one of the H-2K, D, or I regions resulted in an additive, but not potentiating, effect. Genes coded outside the H-2 region did not seem to play a role in this system. In some rare cases, a weak response occurred across allogeneic barriers, but in general, virus-specific T-cell proliferation was strongly H-2 restricted.