bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunity in natural SIV infections
Authors: Silvestri G. 
Published: December 2008

Abstract.In stark contrast to human immunodeficiency virus (HIV)‐infected individuals who, if left untreated, almost invariably progress to acquired immunodeficiency syndrome (AIDS), natural hosts for the simian immunodeficiency viruses (SIV) remain asymptomatic throughout the course of infection. This observation represents one of the main unresolved puzzles of AIDS research, particularly if one considers that natural SIV infections are characterized by chronically high levels of viraemia as well as intrinsic virus cytopathicity comparable with that of HIV. In this review, I discuss the basic immunological features of natural, nonpathogenic SIV infections, the evidence suggesting that attenuated, rather than extraordinarily strong, immune responses to the virus may favour their benign course, and the implications of these findings in terms of HIV therapy and vaccines.
Signalling pathways leading to IFN‐α production in human plasmacytoid dendritic cell and the possible use of agonists or antagonists of TLR7 and TLR9 in clinical indications
Authors: Guiducci C. , Coffman R. L. , Barrat F. J. 
Published: December 2008

Abstract.Plasmacytoid dendritic cells (PDC) are highly specialized immune cells capable of producing large amounts of type I and III IFN in response to viral infection. This response is mediated through TLR7 and TLR9 signalling pathways. In addition, PDC can differentiate into fully mature dendritic cells able to efficiently crosspresent viral antigens, thus playing an important role in adaptive immunity. This dual property of PDC is being used in clinical settings where synthetic TLR7 and TLR9 ligands are currently evaluated in clinical trials for the treatment of viral infections, allergies and cancers. Interestingly, there is evidence suggesting that chronic activation of PDC by endogenous RNA and DNA containing immune complexes maybe an important mechanism of driving autoimmunity and significant efforts to develop bi‐functional antagonists of TLR7 and TLR9 are currently underway.
Antiviral CD8+ T cells in the genital tract control viral replication and delay progression to AIDS after vaginal SIV challenge in rhesus macaques immunized with virulence attenuated SHIV 89.6
Authors: Genescà M. , McChesney M. B. , Miller C. J. 
Published: December 2008

Abstract.The recently failed clinical efficacy trial of an acquired immunodeficiency syndrome (AIDS) vaccine that elicits antiviral CD8+ T‐cell responses has emphasized the challenge of producing an effective vaccine against human immunodeficiency virus (HIV). In the simian immunodeficiency virus (SIV)/ rhesus monkey model of AIDS, live‐attenuated lentivirus ‘vaccines’ provide the best protection from uncontrolled viral replication and clinical disease after pathogenic SIV challenge. This review summarizes a recent series of studies in which we show that after vaginal SIV challenge of rhesus macaques immunized with an attenuated lentivirus protection from uncontrolled viral replication is primarily mediated by CD8+ T cells in the vaginal mucosa. Immunization with a chimeric simian/human immunodeficiency virus (SHIV) results in a systemic infection that induces a moderate population of SIV‐specific CD8+ and CD4+ T cells with cytolytic potential in the vaginal mucosa. Depletion of CD8+ T cells at the time of SIV challenge completely abrogates the protection mediated by prior infection with attenuated SHIV. Further after vaginal SIV challenge, the only significant expansion of SIV‐specific T cells occurs in the vagina in these animals. No significant expansion of T‐cell responses was observed in systemic lymphoid tissues. Thus, the presence of SIV‐specific CD8+ T cells in the vagina on the day of vaginal SIV challenge and a modest expansion of local effector T cells is sufficient to stop uncontrolled SIV replication. It seems that T‐cell based vaccine strategies that can elicit mucosal effector CD8+ T‐cell populations and avoid inducing systemic T‐cell proliferation upon exposure to HIV have the greatest potential for mimicking the success of live‐attenuated lentiviral vaccines.
Developing an HIV cytotoxic T‐lymphocyte vaccine: issues of CD8 T‐cell quantity, quality and location
Authors: Masopust D. 
Published: December 2008

Abstract.Issues of quantity, quality and location impact the ability of CD8 T cells to mediate protection from infection. These issues are considered in light of human immunodeficiency virus (HIV)/simian immunodeficiency virus (SIV) vaccination. Methods are reviewed that result in 100‐ to 1000‐fold higher frequencies of vaccine‐specific memory CD8 T cells than that achieved by current HIV/SIV vaccine approaches. Data demonstrating that location within mucosal tissues has a direct impact on memory CD8 T‐cell function are discussed. Arguments are made that establishing memory CD8 T cells within mucosal sites of transmission, a priori to natural infection, may be essential for conferring optimal and rapid protection. Lastly, it is proposed that heterologous prime‐boost vaccination with recombinant live replicating vectors, which has the potential to induce tremendous numbers of cytolytic memory CD8 T cells within mucosal tissues, would provide a far more stringent test of the hypothesis that memory CD8 T cells could, in principal, form the basis for a preventative HIV vaccine.
Genetic consequences of habitat fragmentation in plant populations: susceptible signals in plant traits and methodological approaches
Authors: AGUILAR RAMIRO , QUESADA MAURICIO , ASHWORTH LORENA , HERRERIAS‐DIEGO YVONNE , LOBO JORGE 
Published: December 2008

AbstractConservation of genetic diversity, one of the three main forms of biodiversity, is a fundamental concern in conservation biology as it provides the raw material for evolutionary change and thus the potential to adapt to changing environments. By means of meta‐analyses, we tested the generality of the hypotheses that habitat fragmentation affects genetic diversity of plant populations and that certain life history and ecological traits of plants can determine differential susceptibility to genetic erosion in fragmented habitats. Additionally, we assessed whether certain methodological approaches used by authors influence the ability to detect fragmentation effects on plant genetic diversity. We found overall large and negative effects of fragmentation on genetic diversity and outcrossing rates but no effects on inbreeding coefficients. Significant increases in inbreeding coefficient in fragmented habitats were only observed in studies analyzing progenies. The mating system and the rarity status of plants explained the highest proportion of variation in the effect sizes among species. The age of the fragment was also decisive in explaining variability among effect sizes: the larger the number of generations elapsed in fragmentation conditions, the larger the negative magnitude of effect sizes on heterozygosity. Our results also suggest that fragmentation is shifting mating patterns towards increased selfing. We conclude that current conservation efforts in fragmented habitats should be focused on common or recently rare species and mainly outcrossing species and outline important issues that need to be addressed in future research on this area.
Global phylogeography and seascape genetics of the lemon sharks (genus Negaprion)
Authors: SCHULTZ J. K. , FELDHEIM K. A. , GRUBER S. H. , ASHLEY M. V. , MCGOVERN T. M. , BOWEN B. W. 
Published: December 2008

AbstractSeascapes are complex environments, and populations are often isolated by factors other than distance. Here we investigate the role of coastal habitat preference and philopatry in shaping the distribution and population structure of lemon sharks. The genus Negaprion comprises the amphiatlantic lemon shark (N. brevirostris), with a relict population in the eastern Pacific, and its Indo‐West Pacific sister species, the sicklefin lemon shark (N. acutidens). Analyzing 138 individuals throughout the range of N. brevirostris (N = 80) and N. acutidens (N = 58) at microsatellite loci (nine and six loci, respectively) and the mitochondrial control region, we find evidence of allopatric speciation corresponding to the Tethys Sea closure (10–14 million years ago) and isolation of the eastern Pacific N. brevirostris population via the emergence of the Isthmus of Panama (~3.5 million years ago). There is significant isolation by oceanic distance (R2 = 0.89, P = 0.005), defined as the maximum distance travelled at depths greater than 200 m. We find no evidence for contemporary transatlantic gene flow (m, M = 0.00) across an oceanic distance of ~2400 km. Negaprion acutidens populations in Australia and French Polynesia, separated by oceanic distances of at least 750 km, are moderately differentiated (FST = 0.070–0.087, P≤ 0.001; ΦST = 0.00, P = 0.99), with South Pacific archipelagos probably serving as stepping stones for rare dispersal events. Migration between coastally linked N. brevirostris populations is indicated by nuclear (m = 0.31) but not mitochondrial (m < 0.001) analyses, possibly indicating female natal site fidelity. However, philopatry is equivocal in N. acutidens, which has the lowest control region diversity (h = 0.28) of any shark yet studied. Restricted oceanic dispersal and high coastal connectivity stress the importance of both local and international conservation efforts for these threatened sharks.
Inferring the history of speciation in house mice from autosomal, X‐linked, Y‐linked and mitochondrial genes
Authors: GERALDES ARMANDO , BASSET PATRICK , GIBSON BARBARA , SMITH KIMBERLY L. , HARR BETTINA , YU HON‐TSEN , BULATOVA NINA , ZIV YARON , NACHMAN MICHAEL W. 
Published: December 2008

AbstractPatterns of genetic differentiation among taxa at early stages of divergence provide an opportunity to make inferences about the history of speciation. Here, we conduct a survey of DNA‐sequence polymorphism and divergence at loci on the autosomes, X chromosome, Y chromosome and mitochondrial DNA in samples of Mus domesticus, M. musculus and M. castaneus. We analyzed our data under a divergence with gene flow model and estimate that the effective population size of M. castaneus is 200 000–400 000, of M. domesticus is 100 000–200 000 and of M. musculus is 60 000–120 000. These data also suggest that these species started to diverge approximately 500 000 years ago. Consistent with this recent divergence, we observed considerable variation in the genealogical patterns among loci. For some loci, all alleles within each species formed a monophyletic group, while at other loci, species were intermingled on the phylogeny of alleles. This intermingling probably reflects both incomplete lineage sorting and gene flow after divergence. Likelihood ratio tests rejected a strict allopatric model with no gene flow in comparisons between each pair of species. Gene flow was asymmetric: no gene flow was detected into M. domesticus, while significant gene flow was detected into both M. castaneus and M. musculus. Finally, most of the gene flow occurred at autosomal loci, resulting in a significantly higher ratio of fixed differences to polymorphisms at the X and Y chromosomes relative to autosomes in some comparisons, or just the X chromosome in others, emphasizing the important role of the sex chromosomes in general and the X chromosome in particular in speciation.
Phylogenetic and population genetic divergence correspond with habitat for the pathogen Colletotrichum cereale and allied taxa across diverse grass communities
Authors: CROUCH JO ANNE , TREDWAY LANE P. , CLARKE BRUCE B. , HILLMAN BRADLEY I. 
Published: December 2008

AbstractOver the past decade, the emergence of anthracnose disease has newly challenged the health of turfgrasses on North American golf courses, resulting in considerable economic loss. The fungus responsible for the outbreaks, Colletotrichum cereale, has also been identified from numerous natural grasses and cereal crops, although disease symptoms are generally absent. Here we utilize phylogenetic and population genetic analyses to determine the role of ecosystem in the advancement of turfgrass anthracnose and assess whether natural grass and/or cereal inhabitants are implicated in the epidemics. Using a four‐gene nucleotide data set to diagnose the limits of phylogenetic species and population boundaries, we find that the graminicolous Colletotrichum diverged from a common ancestor into distinct lineages correspondent with host physiology (C3 or C4 photosynthetic pathways). In the C4 lineage, which includes the important cereal pathogens Colletotrichum graminicola, C. sublineolum, C. falcatum, C. eleusines, C. caudatum and several novel species, host specialization predominates, with host‐associated lineages corresponding to isolated sibling species. Although the C3 lineage —C. cereale— is comprised of one wide host‐range species, it is divided into 10 highly specialized populations corresponding to ecosystem and/or host plant, along with a single generalist population spread across multiple habitat types. Extreme differentiation between the specialized C. cereale populations suggests that asymptomatic nonturfgrass hosts are unlikely reservoirs of infectious disease propagules, but gene flow between the generalist population and the specialized genotypes provides an indirect mechanism for genetic exchange between otherwise isolated populations and ecosystems.
Genetic diversity and gene flow in collapsed and healthy abalone fisheries
Authors: MILLER K. J. , MAYNARD B. T. , MUNDY C. N. 
Published: December 2008

AbstractOverexploitation of marine species invariably results in population decline but can also have indirect effects on ecological processes such as larval dispersal and recruitment that ultimately affect genetic diversity and population resilience. We compared microsatellite DNA variation among depleted and healthy populations of the black‐lip abalone Haliotis rubra from Tasmania, Australia, to determine if over‐fishing had affected genetic diversity. We also used genetic data to assess whether variation in the scale and frequency of larval dispersal was linked to greater population decline in some regions than in others, and if larval dispersal was sufficient to facilitate natural recovery of depleted populations. Surprisingly, allelic diversity was higher in depleted populations than in healthy populations (P < 0.05). Significant subdivision across hundreds of metres among our sampling sites (FST = 0.026, P < 0.01), coupled with assignment tests, indicated that larval dispersal is restricted in all regions studied, and that abalone populations across Tasmania are largely self‐recruiting. Low levels of larval exchange appear to occur at the meso‐scale (7–20 km), but age estimates based on shell size indicated that successful migration of larvae between any two sites may happen only once every few years. We suggest that genetic diversity may be higher in depleted populations due to the higher relative ratio of migrant to self‐recruiting larvae. In addition, we expect that recovery of depleted abalone populations will be reliant on sources of larvae at the meso‐scale (tens of km), but that natural recovery is only likely to occur on a timescale unacceptable to fishers and resource managers.
Lysine restriction and realimentation affected growth, blood profiles and expression of genes related to protein and fat metabolism in weaned pigs
Authors: Yang Y. X. , Guo J. , Jin Z. , Yoon S. Y. , Choi J. Y. , Wang M. H. , Piao X. S. , Kim B. W. , Chae B. J. 
Published: December 2008

SummaryTo investigate the effects of lysine restriction and subsequent realimentation on growth performance, blood profiles and gene expression of leptin and myostatin, 128 weaned pigs [initial body weight (BW) 6.96 ± 1.07 kg, 26 ± 2 days of age] were randomly allotted to four treatments. The starter diets during the first 2 weeks (P1) contained 100%, 80%, 70% or 60% of recommended lysine levels (National Research Council, 1998). Then, common grower 1 and 2 diets were offered for 2 weeks (P2 and P3) each. During P1, average daily gain (ADG) was linearly reduced (p < 0.05) with the increasing levels of lysine restriction. Growth rate was greater in pigs previously fed lysine‐restricted diets than well‐fed pigs although it did not reach a significant level during realimentation. However, the final BW and overall ADG were the lowest (p < 0.05) and F/G was poor in pigs fed 60% lysine diet. Relative visceral organ weights and composition of skeletal muscle were similar (p > 0.05) among the treatment. Blood triglyceride and glucose levels were increased (p < 0.05) during P1, while blood urine nitrogen, total protein and albumin levels were decreased (p < 0.05) during P2 with the reduction in dietary lysine levels. The abundance of myostatin mRNA in skeletal muscle and leptin mRNA in subcutaneous adipose tissue were lower (p < 0.05) in lysine‐restricted pigs than in pigs fed non‐restricted diets. In conclusion, 80% and 70% lysine restriction of starter diets resulted in inferior growth and compensatory growth effect was noted during realimentation, while 60% lysine restriction had a negative influence on growth performance. Moreover, the changes in myostatin and leptin mRNA abundance caused by nutritional manipulations may be involved in the regulation of protein and fat deposition in young pigs.
Performance and dietary preferences of white‐tailed deer grazing chicory, birdsfoot trefoil or alfalfa in north central Alberta
Authors: Chapman G. A. , Bork E. W. , Donkor N. T. , Hudson R. J. 
Published: December 2008

SummaryLittle information exists on the performance of deer on alternative forage species in northern temperate environments during summer and fall, the period of inherent maximum growth in deer. In performance and choice experiments, we compared live weight gain (g/kg0.75/day), absolute [kg/ha dry matter (DM)] and relative (% DM) herbage utilization, relative preference index (RPI) as well as plant community visitation of white‐tailed deer grazing alfalfa (Medicago sativa), birdsfoot trefoil (Lotus corniculatus) or chicory (Cichorium intybus) in north central Alberta, Canada. Herbage phytomass and quality was also measured on the grazed pastures. Alfalfa had higher dry matter yields and crude protein concentrations than chicory and trefoil. Chicory had lower neutral detergent fiber concentrations than the other forages. Tannin concentrations were greatest in birds foot trefoil (nearly 55 g/kg DM), well above those in the other forages (<5 g/kg DM). Live weight gain was similar among deer feeding within the paddocks seeded to birds foot trefoil and chicory, and more than two times higher (p < 0.05) than deer feeding in paddocks seeded to alfalfa. Deer spent more grazing time (about 40%) on chicory pastures than on alfalfa and birds foot trefoil pastures. RPI values were greatest for birds foot trefoil at 2.11, intermediate for chicory at 1.40, and lowest for alfalfa at <0.60. Absolute herbage utilization remained similar (p > 0.05) among the three forage species. In contrast, relative herbage utilization was greater from birds foot trefoil (52% DM) than chicory (40% DM) or alfalfa (25% DM). These results suggest that the use of alfalfa with other alternative forages may prove beneficial to deer production, rather than using alfalfa pasture alone.
Influence of winds and oceanographic conditions on the mucilage aggregation in the Northern Adriatic Sea in 2003–2006
Authors: De Lazzari Amelia , Berto Daniela , Cassin Daniele , Boldrin Alfredo , Giani Michele 
Published: December 2008

AbstractMeteorological and oceanographic conditions in the Northern Adriatic Sea in a year notable for massive mucilage formation (2004) were compared with those in years where this phenomenon did not occur (2003, 2005 and 2006) to suggest possible links. The months preceding the mucilage event in 2004 were considered the ‘incubation period’ and were characterized by a strong freshet in May which increased the water column stability. Winter cooling and scarcity of freshwater inputs from the Po River triggered the dense water formation and intrusion in the northern basin. Weak southeasterly winds and an increase in surface seawater temperatures contributed to maintain and reinforce the water column stability, and at the same time an intense diatom spring bloom created the conditions for accumulation of organic matter. The interplay of climatological forcings and biological processes caused temporal variations of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the basin, with POC playing an important role in the aggregation process, as suggested by its increase relative to DOC before massive mucilage formation. We therefore suggest that high POC/total particulate nitrogen ratios in the suspended particulate organic fraction, a steep increase of POC/Chlorphyll a, and the decreased DOC/POC ratios represent ‘early warning’ signals of the main processes that lead to mucilage events in the Northern Adriatic Sea.
ELECTRONIC RESOURCES FOR SURGICAL ANATOMY
Authors: Choi Ah‐Rin Anna , Tamblyn Rodney , Stringer Mark D. 
Published: December 2008

Background:  Numerous electronic resources are now available to assist students studying anatomy in medicine, dentistry and allied health sciences. Few studies have evaluated these in detail, and there is little guidance as to which are most suitable for the surgical trainee. The aim of this review was to determine which of the currently available electronic resources are most suitable for learning surgically relevant anatomy.Methods:  A structured review was undertaken, beginning with an initial Internet search. Inclusion/exclusion criteria were developed and applied. The selected sites were analysed in detail using a specifically designed survey matrix focusing on background data, content, interactive self‐evaluation features, and surgical relevance.Results:  The initial Internet search identified more than 100 anatomical websites of potential relevance. Of these, 19 online and six stand‐alone multimedia resources were evaluated in detail. These varied considerably in content (atlas, text, graphics, etc.), surgical relevance and cost. Resources most appropriate for surgical trainees tended to offer either three‐dimensional images that should promote a better understanding of spatial anatomy or other technological benefits such as Podcast tutorials.Conclusions:  There are a variety of excellent electronic resources currently available to assist the surgical trainee in acquiring a solid foundation in anatomy. Although many provide useful supplementary material, only a few offer a more comprehensive, surgically relevant framework that could usefully complement practical tuition in anatomy.