1,911 research outputs found

    Competitive mating in Drosophila melanogaster

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    Imported Asian swamp eels (Synbranchidae: Monopterus ) in North American live food markets: Potential vectors of non-native parasites

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    Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus “Clade C”—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus “Clade C” swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites

    Model of Youth Tolerance Limits and Juvenile Delinquency

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    Sociolog

    Dynamic weather effects induced from the 2017 total solar eclipse

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    This research project was part of a nationwide effort organized by Montana Space Grant consortium to study and film the 2017 total solar eclipse with high altitude balloons. Our mission is to measure the changes in light from the total solar eclipse and its effects on the local weather conditions in the air and on the ground. Our results showed that the effects of totality on the ambient light levels were not gradual, like we had expected from our observations of sunsets, but rather the light levels decreased sharply at totality. We measured a 5.61% decrease in light before full totality, followed by a 94.4% decrease, over 90 seconds, into totality. The dramatic decreases in light levels are the root cause for the measured weather phenomena, including a short-term pressure increase associated with totality

    The African origin of plasmodium vivax

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    Gene Loss and Adaptation to Hominids Underlie the Ancient Origin of HIV-1

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    SummaryHIV-1 resulted from cross-species transmission of SIVcpz, a simian immunodeficiency virus that naturally infects chimpanzees. SIVcpz, in turn, is a recombinant between two SIV lineages from Old World monkeys. Lentiviral interspecies transmissions are partly driven by the evolution and capacity of viral accessory genes, such as vpx, vpr, and vif, to antagonize host antiviral factors, such as SAMHD1 and the APOBEC3 proteins. We show that vpx, which in other lentiviruses antagonizes SAMHD1, was deleted during the creation of SIVcpz. This genomic deletion resulted in the reconstruction of the overlapping vif gene by “overprinting,” creating a unique vif that overlaps in its 3′ end with the vpr gene and can antagonize hominid APOBEC3s. Moreover, passage of SIVs through chimpanzees facilitated the subsequent adaptation of HIV-1 to humans. Thus, HIV-1 originated through a series of gene loss and adaptation events that generated its chimpanzee precursor and lowered the species barrier to human infection

    The evolution of HIV-1 and the origin of AIDS

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    The major cause of acquired immune deficiency syndrome (AIDS) is human immunodeficiency virus type 1 (HIV-1). We have been using evolutionary comparisons to trace (i) the origin(s) of HIV-1 and (ii) the origin(s) of AIDS. The closest relatives of HIV-1 are simian immunodeficiency viruses (SIVs) infecting wild-living chimpanzees (Pan troglodytes troglodytes) and gorillas (Gorilla gorilla gorilla) in west central Africa. Phylogenetic analyses have revealed the origins of HIV-1: chimpanzees were the original hosts of this clade of viruses; four lineages of HIV-1 have arisen by independent cross-species transmissions to humans and one or two of those transmissions may have been via gorillas. However, SIVs are primarily monkey viruses: more than 40 species of African monkeys are infected with their own, species-specific, SIV and in at least some host species, the infection seems non-pathogenic. Chimpanzees acquired from monkeys two distinct forms of SIVs that recombined to produce a virus with a unique genome structure. We have found that SIV infection causes CD4(+) T-cell depletion and increases mortality in wild chimpanzees, and so the origin of AIDS is more ancient than the origin of HIV-1. Tracing the genetic changes that occurred as monkey viruses adapted to infect first chimpanzees and then humans may provide insights into the causes of the pathogenicity of these viruses
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