Phylogeny of the mega-diverse Gelechioidea (Lepidoptera): adaptations and determinants of success

The Gelechioidea, with 18,000 described and many more unnamed species ranks among the most diverse lepidopteran superfamilies. Nevertheless, their taxonomy has remained largely unresolved, and phylogenetic affinities among gelechioid families and lower taxa have been insufficiently understood. We constructed, for the first time, a comprehensive molecular phylogeny for the Gelechioidea. We sampled seven genes, in total 5466 base pairs, of 109 gelechioid taxa representing 32 of 37 recognized subfamilies, and two outgroup taxa. We used maximum likelihood methods and Bayesian inference to construct phylogenetic trees. We found that the families Autostichidae, Lecithoceridae, Xyloryctidae, and Oecophoridae s. str., in this order, are the most basally arising clades. Elachistidae s. l. was found to be paraphyletic, with families such as Gelechiidae and Cosmopterigidae nested within it, and Parametriotinae associated with several families previously considered unrelated to them. Using the phylogenetic trees, we examined patterns of life history evolution and determinants of the success of different lineages. Gelechioids express unusually wide variability in life-history strategies, including herbivorous, saprophagous, fungivorous, and carnivorous lineages. Most species are highly specialized in diet and other life history traits. The results suggest that either saprophagy was the ancestral feeding strategy from which herbivory evolved independently on multiple occasions, or that the ancestor was herbivorous with repeated origins of saprophagy. External feeding is an ancestral trait from which internal feeding evolved independently several times. In terms of species number, saprophages are dominant in Australia, while elsewhere several phytophagous lineages have extensively specialized and diversified. Internal feeding has remained a somewhat less generally adopted feeding mode, although in a few lineages significant radiations of leaf mining species have occurred. We conclude that diverse feeding modes, specialization among saprophages, repeated shifts to phytophagy, and a generally high specialization rate on single plant species (monophagy) are the major factors behind the success of the Gelechioidea.     

Effects of Spray Drying on Physicochemical Properties of Chitosan Acid Salts

The effects of spray-drying process and acidic solvent system on physicochemical properties of chitosan salts were investigated. Chitosan used in spray dryings was obtained by deacetylation of chitin from lobster (Panulirus argus) origin. The chitosan acid salts were prepared in a laboratory-scale spray drier, and organic acetic acid, lactic acid, and citric acid were used as solvents in the process. The physicochemical properties of chitosan salts were investigated by means of solid-state CP-MAS ¹³C nuclear magnetic resonance (NMR), X-ray powder diffraction (XRPD), differential scanning calorimetry, and Fourier transform infrared spectrometry (FTIR) and near-infrared spectroscopy. The morphology of spray-dried chitosan acid salts showed tendency toward higher sphericity when higher temperatures in a spray-drying process were applied. Analysis by XRPD indicated that all chitosan acid salts studied were amorphous solids. Solid-state ¹³C NMR spectra revealed the evidence of the partial conversion of chitosan acetate to chitin and also conversion to acetyl amide form which appears to be dependent on the spray-drying process. The FTIR spectra suggested that the organic acids applied in spray drying may interact with chitosan at the position of amino groups to form chitosan salts. With all three chitosan acid salts, the FTIR bands at 1,597 and 1,615 cm⁻¹ were diminished suggesting that –NH groups are protonated. The FTIR spectra of all chitosan acid salts exhibited ammonium and carboxylate bands at 1,630 and 1,556 cm⁻¹, respectively. In conclusion, spray drying is a potential method of preparing acid salts from chitosan obtained by deacetylation of chitin from lobster (P. argus) origin.     

Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging

Since its discovery nearly 30 years ago, more than 60 million people have been infected with the human immunodeficiency virus (HIV) (www.usaid.gov). The virus infects and destroys CD4+ T-cells thereby crippling the immune system, and causing an acquired immunodeficiency syndrome (AIDS) ². Infection begins when the HIV Envelope glycoprotein "spike" makes contact with the CD4 receptor on the surface of the CD4+ T-cell. This interaction induces a conformational change in the spike, which promotes interaction with a second cell surface co-receptor ^5,9. The significance of these protein interactions in the HIV infection pathway makes them of profound importance in fundamental HIV research, and in the pursuit of an HIV vaccine.The need to better understand the molecular-scale interactions of HIV cell contact and neutralization motivated the development of a technique to determine the structures of the HIV spike interacting with cell surface receptor proteins and molecules that block infection. Using cryo-electron tomography and 3D image processing, we recently demonstrated the ability to determine such structures on the surface of native virus, at ˜20 Å resolution ^9,14. This approach is not limited to resolving HIV Envelope structures, and can be extended to other viral membrane proteins and proteins reconstituted on a liposome. In this protocol, we describe how to obtain structures of HIV envelope glycoproteins starting from purified HIV virions and proceeding stepwise through preparing vitrified samples, collecting, cryo-electron microscopy data, reconstituting and processing 3D data volumes, averaging and classifying 3D protein subvolumes, and interpreting results to produce a protein model. The computational aspects of our approach were adapted into modules that can be accessed and executed remotely using the Biowulf GNU/Linux parallel processing cluster at the NIH (http://biowulf.nih.gov). This remote access, combined with low-cost computer hardware and high-speed network access, has made possible the involvement of researchers and students working from school or home.Download video file.^{(47M, mov)}     

Climate-driven diversity dynamics in plants and plant-feeding insects

The origin of species-rich insect-plant food webs has traditionally been explained by diversifying antagonistic coevolution between plant defences and herbivore counter-defences. However, recent studies combining paleoclimatic reconstructions with time-calibrated phylogenies suggest that variation in global climate determines the distribution, abundance and diversity of plant clades and, hence, indirectly influences the balance between speciation and extinction in associated herbivore groups. Extant insect communities tend to be richest on common plant species that have many close relatives. This could be explained either by climate-driven diffuse cospeciation between plants and insects, or by elevated speciation and reduced extinction in herbivore lineages associated with expanding host taxa (resources). Progress in paleovegetation reconstructions in combination with the rapidly increasing availability of fossil-calibrated phylogenies provide means to discern between these alternative hypotheses. In particular, the 'Diffuse cospeciation' scenario predicts closely matching main diversification periods in plants and in the insects that feed upon them, while the 'Resource abundance-dependent diversification' hypothesis predicts that both positive and negative responses of insect diversity are lagged in relation to host-plant availability. The dramatic Cenozoic changes in global climate provide multiple possibilities for studying the mechanisms by which climatic shifts may drive diversity dynamics in plants and insect herbivores.     

Placental size is associated with mental health in children and adolescents

Background

The role of the placenta in fetal programming has been recognized as a highly significant, yet often neglected area of study. We investigated placental size in relation to psychopathology, in particular attention deficit hyperactivity disorder (ADHD) symptoms, in children at 8 years of age, and later as adolescents at 16 years.

Methodology/Principal Findings

Prospective data were obtained from The Northern Finland Birth Cohort (NFBC) 1986. Placental weight, surface area and birth weight were measured according to standard procedures, within 30 minutes after birth. ADHD symptoms, probable psychiatric disturbance, antisocial disorder and neurotic disorder were assessed at 8 years (n = 8101), and ADHD symptoms were assessed again at 16 years (n = 6607), by teachers and parents respectively. We used logistic regression analyses to investigate the association between placental size and mental health outcomes, and controlled for gestational age, birth weight, socio-demographic factors and medical factors, during gestation. There were significant positive associations between placental size (weight, surface area and placental-to-birth-weight ratio) and mental health problems in boys at 8 and 16 years of age. Increased placental weight was linked with overall probable psychiatric disturbance (at 8y, OR  = 1.14 [95% CI  = 1.04–1.25]), antisocial behavior (at 8 y, OR  = 1.14 [95% CI  = 1.03–1.27]) and ADHD symptoms (inattention-hyperactivity at 16y, OR  = 1.19 [95% CI  = 1.02–1.38]). No significant associations were detected among girls.

Conclusions/Significance

Compensatory placental growth may occur in response to prenatal insults. Such overgrowth may affect fetal development, including brain development, and ultimately contribute to psychopathology.     

Trichodysplasia spinulosa-Associated Polyomavirus (TSV) and Merkel Cell Polyomavirus: Correlation between Humoral and Cellular Immunity Stronger with TSV

Merkel Cell Polyomavirus (MCV) is a common infectious agent likely to be involved in the pathogenesis of most Merkel cell carcinomas (MCC). Trichodysplasia spinulosa-associated polyomavirus (TSV), which exhibit high seroprevalence in general population, has been detected in trichodysplasia spinulosa (TS) skin lesions suggesting an etiological role for this disease. Previous studies have shown strong MCV-specific T-cell responses, while no data exist on T-cell immunity against TSV. In order to characterize Th-cell immunity against TSV, and to allow comparisons with the MCV-specific Th-cell immunity, we studied TSV-specific proliferation, IFN-γ, IL-10 and IL-13, and MCV-specific IFN-γ and IL-10 responses in 51 healthy volunteers, and in one MCC patient. Recombinant TSV and MCV VP1 virus-like particles (VLPs) were used as antigens. A significant correlation was found between virus-specific Th-cell and antibody responses with TSV; with MCV it proved weaker. Despite significant homology in amino acid sequences, Th-cell crossreactivity was not evident between these viruses. Some subjects seronegative to both TSV and MCV exhibited Th-cell responses to both viruses. The agent initially priming these Th-cells remains an enigma. As CD8⁺ cells specific to MCV T-Ag oncoprotein clearly provide an important defense against established MCC, the MCV VP1-specific Th-cells may, by suppressing MCV replication with antiviral cytokines such as IFN-γ, significantly contribute to preventing the full process of oncogenesis.     

Dementia and oral health among subjects aged 75 years or older

doi: 10.1111/j.1741‐2358.2010.00396.x Dementia and oral health among subjects aged 75 years or older Objective: To study the association between diagnosed dementia and oral health, focusing on the type of dementia, among an elderly population aged 75 years or older. Background: Elderly people with dementia are at risk from oral diseases, but to date, only a few studies have analysed the association between type of dementia and oral health, and their results are inconclusive. Materials and methods: This cross‐sectional study is based on the Geriatric multi‐disciplinary strategy (Gems) study that included 76 demented and 278 non‐demented subjects. The data were collected by means of an interview and an oral clinical examination. The type of dementia was diagnosed according to DSM‐IV criteria. Poisson’s and logistic regression models were used to determine relative risks (RR), odds ratios (OR) and 95% confidence limits (CI). Results: Our results showed that patients with Alzheimer’s disease and those with other types of dementia had an increased likelihood of having carious teeth, teeth with deep periodontal pockets, and poor oral and denture hygiene, compared with non‐demented persons. The results showed that the type of dementia does not seem to be an essential determinant of oral health. Conclusions: Among the elderly aged 75 years or older, patients with Alzheimer’s disease or other types of dementia are at increased risk of poor oral health and poor oral hygiene.     

Chromosomal fusion and life history‐associated genomic variation contribute to within‐river local adaptation of Atlantic salmon

Chromosomal inversions have been implicated in facilitating adaptation in the face of high levels of gene flow, but whether chromosomal fusions also have similar potential remains poorly understood. Atlantic salmon are usually characterized by population structure at multiple spatial scales; however, this is not the case for tributaries of the Miramichi River in North America. To resolve genetic relationships between populations in this system and the potential for known chromosomal fusions to contribute to adaptation, we genotyped 728 juvenile salmon using a 50 K SNP array. Consistent with previous work, we report extremely weak overall population structuring (Global F_ST = 0.004) and failed to support hierarchical structure between the river's two main branches. We provide the first genomic characterization of a previously described polymorphic fusion between chromosomes 8 and 29. Fusion genomic characteristics included high LD, reduced heterozygosity in the fused homokaryotes, and strong divergence between the fused and the unfused rearrangement. Population structure based on fusion karyotype was five times stronger than neutral variation (F_ST = 0.019), and the frequency of the fusion was associated with summer precipitation supporting a hypothesis that this rearrangement may contribute local adaptation despite weak neutral differentiation. Additionally, both outlier variation among populations and a polygenic framework for characterizing adaptive variation in relation to climate identified a 250‐Kb region of chromosome 9, including the gene six6 that has previously been linked to age‐at‐maturity and run‐timing for this species. Overall, our results indicate that adaptive processes, independent of major river branching, are more important than neutral processes for structuring these populations.