Georgia Populations Research Articles

Regional changes of maximum dose insecticide responses in diamondback moth (Lepidoptera: Plutellidae) populations from Georgia and Florida, USA.

Maximum dose bioassays were conducted to assess the efficacy of multiple registered active ingredients for diamondback moth (DBM), Plutella xylostella (L.), control in Georgia and Florida from 2021 to 2023 as a follow-up to an earlier study. Low efficacy (<40% mortality) was recorded for the highest labeled rate of Bacillus thuringiensis var. kurstaki strain ATBS-351 in Georgia, as well as chlorantraniliprole, cyantraniliprole, and cyclaniliprole in Georgia and Florida. The active ingredients with the highest efficacy (>80% mortality) in both states were naled, emamectin benzoate, and spinetoram. Independent analysis of data by state indicated that the efficacy of bifenthrin, chlorantraniliprole, cyantraniliprole, tolfenpyrad, and methomyl was higher in Florida populations than in Georgia populations. In addition, a comparison of these data to a recent DBM maximum dose survey in the same region suggested that these DBM populations have rapidly developed high levels of resistance to cyantraniliprole and cyclaniliprole. This work provides growers in the region with a recent ranking of insecticide efficacy that documents the loss of control for certain active ingredients, which assists pest managers in the planning of ongoing insecticide rotations for DBM resistance management.

Extension of the geographical range of the primary burrowing crayfish Cambarus strigosus Hobbs, 1981 (Decapoda: Astacidea: Cambaridae) in South Carolina

Abstract Knowledge of the geographical distribution for many primary burrowing crayfishes is often limited to information presented in species descriptions or field notes associated with epigean crayfish surveys. Cambarus strigosusHobbs, 1981, a rare primary burrowing crayfish, was collected as part of a survey of the Sumter National Forest, South Carolina (SC), USA. Prior to this discovery, C. strigosus appeared to be endemic to mid-reaches of the Broad River Drainage in Georgia (GA). We conducted additional field sampling in SC and GA and used mitochondrial DNA (mtDNA) to compare the relative genetic distance between individuals across all populations in an effort to determine the identity of the specimens collected. Genetic data indicated that the crayfish collected in SC was C. strigosus, with one shared haplotype between SC and GA populations. Our genetic results exhibited geographic structuring and indicated that SC populations have a specific haplotype unique to them, providing strong evidence that SC populations are not introduced. Two additional SC records of C. strigosus from 1983 housed in the US National Museum were examined and determined to be C. strigosus. With these records, we hypothesized that like in GA, the distribution of C. strigosus in SC is limited to riparian habitats associated with the Savannah River Drainage. While the range of this species has been extended, it is still limited to small portions of this drainage. Thus, further sampling to determine the true extent of C. strigosus distribution within SC along with conservation efforts are needed to protect this globally rare species.

Not just range limits: Warming rate and thermal sensitivity shape climate change vulnerability in a species range center.

Climate change manifests unevenly across space and time and produces complex patterns of stress for ecological systems. Species can also show substantial among-population variability in response to environmental change across their geographic range due to evolutionary processes. Explanatory factors or their proxies, such as temperature and latitude, help parse these sources of environmental and intraspecific variability; however, overemphasizing latitudinal trends can obscure the role of local environmental conditions in shaping population vulnerability to climate change. Focusing on the geographic center of a species range to disentangle latitude, we test the hypothesis that populations from warmer regions of a species range are more vulnerable to ocean warming. We conducted a mesocosm experiment and field reciprocal transplant with four populations of a marine snail, Nucella lamellosa, from two regions in British Columbia, Canada, that differ in thermal characteristics: the Central Coast, a cool region, and the Strait of Georgia, one of the warmest regions of this species' range and one that is warming faster than the Central Coast. Populations from the Strait of Georgia experienced growth reductions at contemporary summertime seawater temperatures in the laboratory and showed stark reductions in survival and growth under future seawater conditions and when outplanted at their native transplant sites. This indicates a high vulnerability to ocean warming, especially given the faster rate of ocean warming in this region. In contrast, populations from the cooler Central Coast demonstrated high performance at contemporary seawater temperatures and high growth and survival in projected future seawater temperatures and at their native outplant sites. Given their position within the geographic center of N. lamellosa's range, extirpation events in the vulnerable Strait of Georgia populations could compromise connectivity within the metapopulation and lead to gaps across this species' range. Overall, our study supports predictions that populations from warm regions of species ranges are more vulnerable to environmental warming, suggests that the Strait of Georgia and other inland or coastal seas could be focal points for climate change effects and ecological transformation, and emphasizes the importance of analyzing climate change vulnerability in the context of regional environmental data and throughout a species' range.

How distinct killifish populations respond differently to stress

Down the east coast of North America, populations of Atlantic killifish, Fundulus heteroclitus, experience wildly different thermal environments. Southern populations experience water that is, on average, 12°C hotter than northern populations annually. These northern and southern killifish populations cope with stress differently. When fish are stressed, such as when predators are nearby, they activate a suite of mechanisms that regulate the release of the stress hormone cortisol, allowing the fish to remain in good condition. Researchers found previously that killifish from southern populations had higher plasma cortisol levels than killifish from northern populations after they experienced the same stress. To figure out why some fish respond strongly to stress while others do not, Madison Earhart and co-workers from the University of British Columbia, Canada, with colleagues from the University of Manitoba, Canada, and the University of Glasgow, UK, set out to determine what genes are responsible for the differences in killifish stress responses by investigating different mechanisms that trigger cortisol release after experiencing stress.Earhart and colleagues travelled to the USA and collected adult killifish from northern New Hampshire and southern Georgia populations. Then, they brought the fish back to the lab in British Columbia. First, the team wanted to see whether the differences in population stress response changed when the fish experienced stress briefly or were exposed to the same stress repeatedly over the period of a week by either putting the fish in buckets and shaking them for half an hour or repeatedly shaking them every day for a week. After stressing the fish, the team collected samples of the fish's blood to measure their cortisol plasma levels, in addition to collecting samples of the fish's brain, head kidney – the organ that produces cortisol – and liver – the organ that produces and breaks down glucose – to measure the expression of genes important for the production and release of cortisol due to stress.After experiencing the single stressful situation, the southern killifish population had higher cortisol levels than the northern killifish population. However, when the fish were repeatedly stressed over the period of a week, there was no difference in cortisol levels between the northern and southern populations. The southern population of killifish, which had a stronger response to the individual stressful situation, expressed more of the genes involved in cortisol production in the brain and head kidney. In addition, the livers of fish from the southern population were more responsive to the cortisol stress hormone as they expressed larger amounts of the gene for the protein that triggers the protective mechanisms that are activated by cortisol when a fish is stressed.The team also measured the condition of the fish after repeated stress. They found that the southern killifish, which were more stress responsive than the northern killifish, were in better condition after experiencing repeated stress than were northern populations. This showed that responding to stress by increasing cortisol was beneficial for the southern population of fish.Earhart and colleagues noted that the answer as to why some fish respond more strongly to stress than others is more complex than simply increasing cortisol levels in the body. They showed that there are differences in the expression of genes all along the pathways that make cortisol, respond to cortisol and cease cortisol production in these two different populations of fish. Therefore, it is important to continue to study these differences in populations of the same species adapted to different environments.

Compensating for Small Body Size: The Reproductive Ecology of Southern Spotted Turtle (Clemmys guttata) Populations

Gradients in environmental conditions across a species' geographic distribution can drive variability in a variety of life history traits. In North American freshwater turtles, both body and clutch size have commonly been shown to vary latitudinally, and these two traits are often directly related, with larger individuals producing larger clutches. We studied the reproductive ecology in two Georgia populations of Spotted Turtles (Clemmys guttata) from 2016–2020 by attaching radio transmitters to female turtles during the breeding season. We x-rayed turtles to determine clutch sizes and used thread bobbins to locate nesting locations, allowing us to determine nest fates. Across all Spotted Turtle clutches (n = 41), mean clutch size was 2.1 (range: 1–4) eggs per clutch. Approximately 92% of individuals that we monitored produced at least one clutch during the breeding season, and we identified 16 instances of individuals producing more than one clutch in a single year, including six turtles triple clutching during 2018. We located 24 Spotted Turtle nests during the study, nine (37.5%) of which either hatched or partially hatched. The other nests were either depredated (41.7%), did not hatch due to infertility or environmental reasons (8.3%), or had an undetermined fate (12.5%). Our results indicate that annual reproductive output in southern Spotted Turtle populations can exceed that of northern populations where individuals produce a single larger clutch per reproductive season. Finally, opportunistic observations in Florida from 2014–2021 indicated that the reproductive season can begin over a month earlier than in southern Georgia, highlighting the variability in reproductive ecology even across a relatively short latitudinal distance.

Phylogenetic relationships and genetic variations among cinereous vultures Aegypius monachus in South Korea

Mature individuals of the cinereous vulture, Aegypius monachus, number 15,600–21,000 birds worldwide and population size of the bird has been in decline due to poisoned baits and the decreasing availability of food. Approximately 12–16% of the global population of cinereous vultures spend their winters in Korean regions that are hence important areas. In this study, the population structure and genetic diversity of the cinereous vulture in South Korea were evaluated to clarify the relationships between the Mongolian and South Korean populations with genetic diversity assessed using mitochondrial DNA (mtDNA) and microsatellite markers. In the South Korean population, two unique haplotypes (Hap8 and Hap9) were newly discovered in their mtDNA, with three polymorphic sites and low-level genetic diversity. Most of the cinereous vultures in South Korea were represented by a single haplotype, Hap8, and analyses of phylogenetic trees and the haplotype network illustrated that Hap8 was clustered in Lineage D (Mongolia). Notably, the other haplotype, Hap9, was only identified in one individual in South Korea with an unexpected clustering in Lineage C (Caucasus region, Armenia, Georgia, and Kazakhstan populations), which indicated that it might have been a vagrant bird. The microsatellite loci ( n = 21) isolated from South Korean cinereous vultures indicated comparatively lower genetic variation, with a K value of 1. These results indicate that the origin of the South Korean population is most likely from one source population of the Far Eastern cluster (Mongolian population), which was also supported by the outcome of mtDNA analysis. This study improves our understanding of the population structure and genetic diversity between the Mongolian and South Korean cinereous vulture populations.

A Target Site Mutation Associated With Diamide Insecticide Resistance in the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae) is Widespread in South Georgia and Florida Populations.

Laboratory colonies of diamondback moth (DBM) larvae were established from larvae collected from four sites in Georgia and Florida where diamide, specifically chlorantraniliprole, insecticide resistance was recently documented. Based on dose-response experiments, these colonies exhibited 109- to 4,298-fold resistance to chlorantraniliprole, compared to a commercially available susceptible control colony. Colonies exhibited 50- to 107-fold resistance to another diamide, cyantraniliprole, based on similar dose-response experiments. All colonies were screened for the presence of four known mutations in the ryanodine receptor (RyR), the target of diamide insecticides, previously associated with resistance in Asian DBM populations. One mutation, G4946E, was identified in colonies from all four field sites, but not the susceptible control colony. Three additional RyR target site mutations, E1338D, Q4594L, and I4790M, were not identified in any of the screened samples. The estimated allele frequency of the G4946E mutation in these colonies ranged from 32 to 90%. These data are consistent with recently reported chlorantraniliprole control failures in Georgia and Florida. It is likely that the G4946E mutation is currently an important contributing factor to chlorantraniliprole resistance in Georgia and Florida DBM populations.

Reproductive incompatibility between Amblyomma maculatum (Acari: Ixodidae) group ticks from two disjunct geographical regions within the USA.

The Amblyomma maculatum Koch group of ixodid ticks consists of three species: A. maculatum, A. triste, and A. tigrinum. However, since Koch described this group in 1844, the systematics of its members has been the subject of ongoing debate. This is especially true of A. maculatum and A. triste; recent molecular analyses reveal insufficient genetic divergence to separate these as distinct species. Further confounding this issue is the discovery in 2014 of A. maculatum group ticks in southern Arizona (AZ), USA, that share morphological characteristics with both A. triste and A. maculatum. To biologically evaluate the identity of A. maculatum group ticks from southern Arizona, we analyzed the reproductive compatibility between specimens of A. maculatum group ticks collected from Georgia (GA), USA, and southern Arizona. Female ticks from both Arizona and Georgia were mated with males from both the Georgia and Arizona Amblyomma populations, creating two homologous and two heterologous F1 cohorts of ticks: GA ♀/GA ♂, AZ ♀/AZ ♂, GA ♀/AZ ♂, and AZ ♀/GA ♂. Each cohort was maintained separately into the F2 generation with F1 females mating only with F1 males from their same cohort. Survival and fecundity parameters were measured for all developmental stages. The observed survival parameters for heterologous cohorts were comparable to those of the homologous cohorts through the F1 generation. However, the F1 heterologous females produced F2 egg clutches that did not hatch, thus indicating that the Arizona and Georgia populations of A. maculatum group ticks tested here represent different biological species.

Distribution and Genetic Diversity of the Rare Plant Veratrum woodii (Liliales: Melanthiaceae) in Georgia: A Preliminary Study with AFLP Fingerprint Data

Veratrum woodii, a long-lived herbaceous perennial species, has a fragmented distribution with populations scattered in the southeastern and lower midwestern USA. In Georgia, the species has a protection status of rare. This preliminary study focused on verifying historic and/or unvouchered populations in Georgia and characterizing variation and genetic structure within and among all populations in the state. We analyzed AFLP (amplified fragment length polymorphism) data as dominantly inherited markers for 16 populations sampled from Georgia, Florida, and Missouri. Our results suggest that this species overall has relatively low levels of genetic diversity and that differentiation among populations is comparable to species with similar life history traits. Measures of genetic diversity, such as mean He, indicate that variation of populations has some partitioning between disjunct northern and southern Georgia (and Florida) populations. However, our analyses imply that watershed assignment, rather than geographic distance, provides a better explanation for variation and population structure. We hypothesize that southern relict populations in Georgia may have served as refugia during Pleistocene glaciations. We conclude that life-history characteristics, low levels of genetic variation, and suppression of ecological disturbance collectively jeopardize populations of Veratrum woodii in Georgia.

Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia

South Georgia supports globally important populations of seabirds, including the wandering albatross Diomedea exulans, black-browed albatross Thalassarche melanophris and grey-headed albatross T. chrysostoma, currently classified by the world Conservation Union (IUCN) as vulnerable, near threatened and endangered, respectively. Surveys of these species at South Georgia were conducted during the incubation stage in November 2014 to January 2015, repeating previous surveys conducted in the 2003/2004 season. Numbers of wandering albatrosses breeding annually at South Georgia decreased by 18% (1.8% per year) from 1553 pairs in 2003/2004 to an estimated 1278 pairs in 2014/2015. Over the same period, black-browed and grey-headed albatrosses decreased by 19% (1.9% per year) and 43% (5% per year), respectively. These represent a continuation of negative trends at South Georgia since the 1970s and are in contrast to some populations elsewhere, which have shown signs of recent recovery. Given the importance of South Georgia for these species, the ongoing population declines, and in the case of grey-headed albatrosses, an acceleration of the decline is of major conservation concern. Incidental fisheries mortality (bycatch) is currently considered to be the main threat. Although seabird bycatch has been reduced to negligible levels in the fisheries operating around South Georgia, wider implementation of effective seabird bycatch mitigation measures is required to improve the conservation status of the South Georgia populations of wandering, black-browed and grey-headed albatrosses. In addition, more research is required to investigate the respective roles of bycatch and climate change in driving these population trends.

Diachronic Evidence in Nonmetric Morphological Characters of Teeth in Armenian Highland and Georgia Populations

The aim of the study is the assessment of biological distance between populations from Arme-nian highland and Georgia based on the frequency of nonmetric odontological traits. These traits are characterized by high inter-population differentiation, low sexual dimorphism, and relatively small intra and inter observer recordation error. This paper presents the results of the odontological differentiation of human populations from Armenian highland and Georgia. The comparative analysis was carried out on 12 populations. Trait frequencies for all populations were analysed using principal component analysis. Results support the following conclusions: The populations of Armenian highland and Georgia can be differentiated as far as the frequency of odontological traits are concerned. Biocultural diversity of ancient Transcaucasian populations has not been studied extensively, therefore delineating some of the patterns of phenotypic variation may be useful for understanding their ongoing evolution.

Surveillance for upper respiratory tract disease and Mycoplasma in free-ranging gopher tortoises (Gopherus polyphemus) in Georgia, USA.

Abstract Upper respiratory tract disease (URTD) in the gopher tortoise (Gopherus polyphemus) is highly contagious and has been implicated in the reduction of populations throughout the range. With the exception of a few limited studies, the prevalence of URTD in Georgia, USA tortoise populations is poorly known. We found that exposure to Mycoplasma agassizii and Mycoplasma testudineum, associated with URTD, varied geographically among 11 Georgia tortoise populations. The prevalence of antibodies to M. agassizii in individual populations was either very low (0-3%, n=7 populations) or very high (96-100%, n=4 populations), whereas there was variation in the prevalence of antibodies to M. testudineum among populations (20-61%, n=10) with only one site being negative. Five sites had tortoises with antibodies to both pathogens, and these were the only sites where we observed tortoises with clinical signs consistent with URTD. We did not find tortoises with clinical signs of URTD at sites with tortoises with antibodies only to M. testudineum, which provides evidence that this organism may be of limited pathogenicity for gopher tortoises. Collectively, these data indicate that both M. agassizii and M. testudineum are present in Georgia populations of gopher tortoises and that clinical disease is apparent in populations where both pathogens are present. Additional research is needed to better understand the role of these two pathogens, and other potential pathogens, in the overall health of tortoise populations, especially if future conservation efforts involve translocation of tortoises.

Population Genetic Structure of &lt;I&gt;Pseudatomoscelis seriatus&lt;/I&gt; (Hemiptera: Miridae) in the Cotton-Growing Regions of the United States

The cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae) is an economically important insect pest of cotton in the United States. However, reports of cotton fleahopper infestation and its management in cotton fields are restricted primarily to Texas, Oklahoma, and Arkansas. The objective of this study was to understand the genetic diversity of cotton fleahopper populations infesting cotton in the cotton-growing areas of the United States. Amplified fragment length polymorphism markers were used to detect genetic diversity and to characterize geographic genotypes across the distribution of the cotton fleahopper in the United States. We used 172 individuals and 559 amplified fragment length polymorphism loci in this study and found significant, but low, level of genetic differentiation among geographic populations (F(ST) = 0.02; P < 0.0001). Molecular fingerprints of cotton fleahopper populations were partitioned into three broad regional genetic populations with a western, central, and eastern distribution. The western (Arizona) and eastern (Florida, Georgia, South Carolina, and North Carolina) populations are genetically distinct, whereas the central (Texas, Oklahoma, Arkansas, Mississippi, Louisiana, and Alabama) population represents an admixed population, which include both western and eastern populations. These results suggest considerable gene flow among the populations within regions but restricted gene flow among populations from eastern and western region.

Mental illness in metropolitan, urban and rural Georgia populations

BackgroundMental illness represents an important public health problem. Local-level data concerning mental illness in different populations (e.g., socio-demographics and residence – metropolitan/urban/rural) provides the evidence-base for public health authorities to plan, implement and evaluate control programs. This paper describes prevalence and covariates of psychiatric conditions in Georgia populations in three defined geographic areas.MethodsData came from the Georgia population-based random-digit-dialing study investigating unwellness and chronic fatigue syndrome (CFS) in Georgia populations of three defined geographic areas (metropolitan, urban, and rural). Respondents were screened for symptoms of fatigue, sleep, cognition, and pain at household screening interviews, and a randomly selected sample completed detailed individual phone interviews. Based on the detailed phone interviews, we conducted one-day clinical evaluations of 292 detailed interview participants classified as unwell with a probable CFS (i.e. CFS-like; a functional somatic syndrome), 268 classified as other unwell, and 223 well (matched to CFS-like). Clinical evaluation included psychiatric classification by means of the Structured Clinical Interview for DSM (SCID). To derive prevalence estimates we used sample weighting to account for the complexity of the multistage sampling design. We used 2- and 3-way table analyses to examine socio-demographic and urbanicity specific associations and multiple logistic regression to calculate adjusted odds ratios.ResultsAnxiety and mood disorders were the most common psychiatric conditions. Nineteen percent of participants suffered a current anxiety disorder, 18% a mood disorder and 10% had two or more conditions. There was a significant linear trend in occurrence of anxiety or mood disorders from well to CFS-like. The most common anxiety disorders were post-traumatic stress disorder (PTSD) (6.6%) and generalized anxiety disorder (GAD) (5.8%). Logistic regression showed that lower education and female sex contributed significantly to risk for both PTSD and GAD. In addition, rural/urban residence and Hispanic ethnicity were associated with PTSD. We defined moderate to severe depression as Major Depressive Disorder or a Zung score >60 and logistic regression found lower education to be significantly associated but sex, age and urbanicity were not.ConclusionsOverall occurrence of anxiety and mood disorders in Georgia mirrored national findings. However, PTSD and GAD occurred at twice the published national rates (3.6 and 2.7%, respectively). State and local prevalence and associations with education, sex and urbanicity comprise important considerations for developing control programs. The increased prevalence of anxiety and mood disorders in people with a functional somatic syndrome (or CFS-like illness) is important for primary care providers, who should consider additional psychiatric screening or referral of individuals presenting with somatoform symptoms.

Geographic distribution of genetic variation among native and introduced populations of Chinese tallow tree, Triadica sebifera (Euphorbiaceae)

Invasive plants often display genetically determined variation in patterns of growth and resource allocation between native and introduced genotypes, as well as among genotypes within different regions of the introduced range. We examined patterns of genetic variation within and among native and introduced populations of the tetraploid Chinese tallow tree (Triadica sebifera, Euphorbiaceae) to determine whether nonselective evolutionary processes or the introduction history could contribute to previously observed phenotypic differences between native and introduced populations as well as among introduced populations. We used six microsatellite markers to study 12 native populations in China, 51 introduced populations in the southeastern USA, and one introduced population in Australia. Genetic diversity was greater within and among native populations than introduced populations. Within the southeastern USA, populations in Georgia and South Carolina differed substantially in their genetic composition and had greater genetic diversity than the rest of the southeastern USA. Greater genetic similarity between some populations in the native range and introduced range indicate a common provenance for Georgia and South Carolina populations that could have come from any of several western or southern Chinese populations and a different provenance for other southeastern USA populations and the Australian population, which were most similar to more northeastern Chinese populations. Differences among introduced populations in potentially adaptive traits (e.g., herbivore tolerance, herbivore resistance, growth rates) may result in part from the introduction history, in particular from differences present among source populations in the native range.

The Opposite of Speciation: Genetic Relationships Among the Populations ofPleurocera(Gastropoda: Pleuroceridae) in Central Georgia*

The ranges of Pleurocera (formerly Goniobasis or Elimia) catenaria (Say, 1822) and P. proxima (Say, 1825) extend from Virginia south through the Carolinas into the piedmont and upper coastal plain of Georgia, where they intersect with populations of P. floridensis (Reeve, 1860). In contrast to the situation in surrounding states, however, Georgia populations of P. catenaria have been taxonomically subdivided and re-described under at least ten specific nomina, over a complex monographic history extending 150 years. To see if this increased nomenclatural diversity might signal higher levels of population divergence, we compared gene frequencies at 11 polymorphic allozyme-encoding loci among eight populations of P. catenaria and three populations of P. floridensis sampled from central Georgia region to three populations of P. proxima, which have never been taxonomically subdivided. Genetic variation was moderate within our 14 populations and high among them, as has been reported in many prior surveys of pleurocerid allozyme divergence conducted elsewhere. The pairwise genetic distances demonstrated among our populations of P. catenaria from Georgia were lower than those observed among control P. proxima populations, or among a comparable sample of P. catenaria populations from the Carolinas previously published. Central Georgia does not appear to be a region of pleurocerid endemicity, but rather of faunal suturing, the proliferation of specific nomina attributable to qualitatively higher levels of shell morphological variation, possibly ecophenotypic in origin. Junior synonyms of P. catenaria include albanyensis, boykiniana, caelatura, darwini, mutabilis, postelli, suturalis and viennaensis. Junior synonyms of P. floridensis include inclinans, induta, exul, and nymphaea. The Goodrich nomen timidus is retained as a subspecies of P. floridensis (new combination). We suggest that faunas demonstrating great evolutionary stasis, such as the pleurocerid populations of central Georgia, might profitably serve as the next “laboratories of speciation.”

Absence of evidence of Xenotropic Murine Leukemia Virus-related virus infection in persons with Chronic Fatigue Syndrome and healthy controls in the United States

BackgroundXMRV, a xenotropic murine leukemia virus (MuLV)-related virus, was recently identified by PCR testing in 67% of persons with chronic fatigue syndrome (CFS) and in 3.7% of healthy persons from the United States. To investigate the association of XMRV with CFS we tested blood specimens from 51 persons with CFS and 56 healthy persons from the US for evidence of XMRV infection by using serologic and molecular assays. Blinded PCR and serologic testing were performed at the US Centers for Disease Control and Prevention (CDC) and at two additional laboratories.ResultsArchived blood specimens were tested from persons with CFS defined by the 1994 international research case definition and matched healthy controls from Wichita, Kansas and metropolitan, urban, and rural Georgia populations. Serologic testing at CDC utilized a Western blot (WB) assay that showed excellent sensitivity to MuLV and XMRV polyclonal or monoclonal antibodies, and no reactivity on sera from 121 US blood donors or 26 HTLV-and HIV-infected sera. Plasma from 51 CFS cases and plasma from 53 controls were all WB negative. Additional blinded screening of the 51 cases and 53 controls at the Robert Koch Institute using an ELISA employing recombinant Gag and Env XMRV proteins identified weak seroreactivity in one CFS case and a healthy control, which was not confirmed by immunofluorescence. PCR testing at CDC employed a gag and a pol nested PCR assay with a detection threshold of 10 copies in 1 ug of human DNA. DNA specimens from 50 CFS patients and 56 controls and 41 US blood donors were all PCR-negative. Blinded testing by a second nested gag PCR assay at the Blood Systems Research Institute was also negative for DNA specimens from the 50 CFS cases and 56 controls.ConclusionsWe did not find any evidence of infection with XMRV in our U.S. study population of CFS patients or healthy controls by using multiple molecular and serologic assays. These data do not support an association of XMRV with CFS.

Shortened duration of the annual Neocalanus plumchrus biomass peak in the Northeast Pacific

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 393:189-198 (2009) - DOI: https://doi.org/10.3354/meps08044 Shortened duration of the annual Neocalanus plumchrus biomass peak in the Northeast Pacific Sonia D. Batten1,*, David L. Mackas2 1Sir Alister Hardy Foundation for Ocean Science, c/o 4737 Vista View Cr., Nanaimo, British Columbia V9V 1N8, Canada 2Fisheries and Oceans Canada, Institute of Ocean Sciences, PO Box 6000, Sidney, British Columbia V8L 4B2, Canada *Email: soba@sahfos.ac.uk ABSTRACT: The calanoid copepod Neocalanus plumchrus (Marukawa) is a dominant member of the spring mesozooplankton in the subarctic North Pacific and Bering Sea. Previous studies have shown interdecadal and latitudinal variation in seasonal developmental timing, with peak biomass occurring earlier in years and places with warmer upper ocean temperatures. Because N. plumchrus normally has a single dominant annual cohort, its seasonal timing can be indexed from measurements of total population biomass or by following progressive changes in stage composition. Early studies empirically found that peak upper ocean biomass occurred when about half of the pre-dormant population had reached copepodite stage 5 (C5). However, more recent comparisons derived from recent Continuous Plankton Recorder (CPR) data now show peak biomass when a larger fraction (>80%) of the population is at C5. CPR samples the surface 10 to 15 m, but comparisons to depth-resolved BIONESS data show that this discrepancy is not an artefact of sampling depth. Other causes are either a prolongation of duration of pre-dormant C5 or a narrowing of the age range making up the annual cohort. We assessed changes in cohort width using a modification of Greve’s cumulative percentile method, and found that average cohort widths in the Alaska Gyre were significantly narrower in 2000–2007 than in 1957–1965 (1968–1980 were intermediate). Net tow sampling of Strait of Georgia populations showed a similar significant narrowing of cohorts in the 2003–2005 sampling period. This study provides evidence that in addition to the shift to an earlier occurrence of peak biomass reported previously, the duration of the peak has also decreased in the last decade. KEY WORDS: Neocalanus plumchrus · Copepod · Biomass · Continuous Plankton Recorder Full text in pdf format PreviousNextCite this article as: Batten SD, Mackas DL (2009) Shortened duration of the annual Neocalanus plumchrus biomass peak in the Northeast Pacific. Mar Ecol Prog Ser 393:189-198. https://doi.org/10.3354/meps08044Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 393. Online publication date: October 30, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Hypersomnolence and Sleep-related Complaints in Metropolitan, Urban, and Rural Georgia

Persistent daytime hypersomnolence is associated with significant morbidity and mortality, but its prevalence in the population has been poorly documented. This study sought to characterize the prevalence of persistent daytime hypersomnolence, difficulties initiating and maintaining sleep, unrefreshing sleep, snoring, and the presence of physician-diagnosed sleep disorders in metropolitan, urban, and rural US Georgia populations. Between September 2004 and July 2005, a total of 6,530 randomly selected well and unwell adults, identified by screening interviews of 10,837 households (contacted by random digit dialing), completed a detailed phone interview. Sixteen percent reported persistent problems staying awake during the day; 26% reported persistent problems falling asleep at night; 31% experienced problems sleeping through the night; 34% were bothered by unrefreshing sleep; and 33% reported that they snored. In spite of the high occurrence of reported persistent sleep problems, only 10% of the survey participants reported having been diagnosed with a sleep disorder. These study findings highlight the need for increased public and clinician awareness with respect to proactively indentifying signs and symptoms of sleep disorders, a better understanding of their adverse impact upon morbidity and mortality, and their negative impact upon socioeconomic and academic potential.

Comparison of population genetic diversity between a rare, narrowly distributed species and a common, widespread species of Alnus (Betulaceae)

Comparisons of population genetic diversity between related rare and widespread species provide valuable insights to the consequences of rarity and are critical for conservation planning. Population genetic diversity of A. maritima, a rare species, was compared with its common, widespread congener A. serrulata to evaluate the impacts of small population size and high isolation on genetic diversity in A. maritima and to provide population genetic data to be used in conservation planning for A. maritima. Genetic data were also used to evaluate whether the disjunct distribution of A. maritima was due to range reduction or anthropogenic dispersal. Genetic diversity was lower in A. maritima (H(e) = 0.217) than in A. serrulata (H(e) = 0.268), and there is also higher inbreeding within A. maritima populations (f = 0.483) than A. serrulata populations (f = 0.269). The partitioning of genetic variation was also higher among A. maritima populations (Θ = 0.278), but not significantly different from that of A. serrulata (Θ = 0.197). Significant genetic differences among A. maritima populations support using local populations as seed sources for regional conservation efforts. The results also indicate that the highly disjunct distribution of A. maritima is due to natural range reduction in the past and not anthropogenic establishment of Oklahoma and Georgia populations.