Expression of immunity and general condition in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), in relation to origin and gender

In immunoecological studies, experimental effects usually explain a relatively small proportion of total variation observed in immune parameters, while the large amount of variation remains unexplained. It is crucial to be aware of such natural variation of immune parameters, which may overshadow the effects of the experiment. We examined factors responsible for variation in cellular immunity (estimated as hemocyte concentration) and general condition (estimated as fresh weight) in the Colorado potato beetle, Leptinotarsa decemlineata, originating from two neighboring potato fields, in a common garden experiment. Progeny of beetles collected from the “New” field, where potato was cultured for the first year, had significantly higher hemocyte concentration and fresh weight compared to individuals originating from the “Old” field, where potato had been cultured for several years. Furthermore, hemocyte concentration varied with respect to gender only in beetles originating from the New field, where males had a higher hemocyte concentration than females. No such sex differences were found in beetles originating from the Old field, suggesting that immune traits and general condition of insects originating from geographically close locations/populations may express different sources of variation. Therefore, generalization of immunity–life‐history trade‐offs based on one population/location should be treated with caution.     

Identification of genetic variants in TNF receptor 2 which are associated with the development of cervical carcinoma

Cervical cancer is one of the most common malignancies among women in India. Beside HPV, other factors present in host also put their role in the progression of cervical tumerogenesis. In present study, we screened 300 subjects to identify variations in TNFR2 gene by PCR-dHPLC method followed by direct sequencing. We identified six known and four novel variations in six different exons of TNFR2 gene. Out of these identified variations, five known variations were found to be significantly associated with the risk of cervical cancer (p?<?0.0001). On construction of haplotypes, one haplotype (TTGCC) was emerged as a major protective type while two (CAAGC?+?CTGCC) were revealed as major risk haplotypes. In conclusion, postmenopausal women having CAAGC?+?CTGCC haplotypes in TNFR2 gene along with HPV infection and tobacco consumption may lead to the development of cervical cancer.     

Numerical Exploration of the Planktonic to Benthic Primary Production Ratios in Lakes of the Baltic Sea Catchment

Autotrophic structure refers to the partitioning of whole-ecosystem primary production between benthic and planktonic primary producers. Autotrophic structure remains poorly understood especially because of the paucity of estimates regarding benthic primary production. We used a conceptual model for numerically exploring the autotrophic structure of 13 hemiboreal lakes situated in the Baltic Sea catchment. We also used diel variations in primary production profiles to graphically evaluate levels of light and/or nutrient limitation in lakes. The input morphometric data, light extinction coefficients and dissolved carbon parameters were mostly obtained from in situ measurements. Results revealed that cross- and within-lake autotrophic structure varied greatly: one lake was clearly dominated by benthic production, and three lakes by phytoplankton production. In the rest, phytoplankton production was generally dominant but switch to benthic dominance was possible. The modelled primary production profiles varied according to lake water clarity and bathymetry. Our results clearly indicate that the relative contribution of benthic primary production to whole-lake primary production should be taken into account in studies about hemiboreal and boreal lakes.     

Influence of the landscape on dispersal of sylvatic triatomines to anthropic habitats in the Atlantic Forest

Aim The aim of this study was to test the hypothesis that the dispersal of sylvatic triatomines to anthropic habitats is stimulated by degradation of their natural habitat. Location State of Espírito Santo, south‐eastern Brazil. Methods We georeferenced records of domiciliary captures of sylvatic triatomines (1996–2005) obtained from the database of the entomological surveillance programme of the Brazilian National Health Foundation. We partitioned the study area into 543 equal hexagons and attributed information on the presence/absence of triatomines and climatic, topographic and biological variables to each. Using generalized additive models (GAMs), we defined the determinant variables for triatomine presence/absence and demarcated the potential areas in which they might occur. We then subjected the hexagons with a high probability of triatomine presence to a second analysis, adding information on the number of domiciliary captures of triatomines and landscape indices that measured quantitative and spatial patterns of forest fragments. We used GAMs to determine the indices that influenced the number of domiciliary captures of triatomines. Results The presence of triatomines was characterized by a strong positive correlation with variability of terrain slope. This variable was used to demarcate the areas where triatomines were likely to occur. Landscape indices associated with the number of domiciliary captures of triatomines were the number of patches, the fractal dimension index, the total core area and the clumpiness index. Main conclusions Our results do not support the hypothesis that domiciliary invasion by sylvatic triatomines is stimulated by environmental degradation. Instead, the results suggest that less degraded areas maintain larger populations of triatomines and consequently present higher indices of dispersal and domiciliary invasion. Particular landscape patterns and dispositions of human dwellings, however, may enhance the probability of triatomines being attracted to the artificial light of dwellings. Initiation of flight and consequent dispersal is a naturally occurring process that allows triatomines to find and colonize areas that favour the survival of their offspring.     

Dynamics of feeding and defecation in Triatoma vitticeps (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) and its potential in the transmission of Trypanosoma cruzi

Adults of Triatoma vitticeps infected by flagellates similar to Trypanosoma cruzi are frequently captured by the inhabitants of rural areas in the Brazilian state of Espirito Santo. The dynamics of feeding and defecation were observed in three groups of adult triatomines, consisting of sylvatic T. vitticeps and laboratory-reared specimens of this species and T. infestans. Triatomines were observed from the moment they were presented with an immobilized chicken as a bloodmeal source until 240 min after feeding had ended. Mean times between the end of feeding and defecation for T. infestans, wild T. vitticeps and laboratory-reared specimens of the latter species were 1.2, 21.1, and 64 min respectively. All T. infestans defecated within 10 min of feeding, while only 29.9 of wild and 52.8% laboratory-reared specimens of T. vitticeps did so within this period. These results may explain the low efficiency of T. vitticeps in T. cruzi transmission to man. The shorter time between feeding and defecation in laboratory-reared T. vitticeps may indicate a change in behaviour of this species as a result of adaptation to an artificial environment.     

Leveraging genomic resources of model species for the assessment of diversity and phylogeny in wild and domesticated lentil

Advances in comparative genomics have provided significant opportunities for analysis of genetic diversity in species with limited genomic resources, such as the genus Lens. Medicago truncatula expressed sequence tags (ESTs) were aligned with the Arabidopsis thaliana genome sequence to identify conserved exon sequences and splice sites in the ESTs. Conserved primers (CPs) based on M. truncatula EST sequences flanking one or more introns were then designed. A total of 22% of the CPs produced polymerase chain reaction amplicons in lentil and were used to sequence amplicons in 175 wild and 133 domesticated lentil accessions. Analysis of the sequences confirmed that L. nigricans and L. ervoides are well-defined species at the DNA sequence level. Lens culinaris subsp. odemensis, L. culinaris subsp. tomentosus, and L. lamottei may constitute a single taxon pending verification with crossability experiments. Lens culinaris subsp. orientalis is the progenitor of domesticated lentil, L. culinaris subsp. culinaris (as proposed before), but a more specific area of origin can be suggested in southern Turkey. We were also able to detect the divergence, following domestication, of the domesticated gene pool into overlapping large-seeded (megasperma) and small-seeded (microsperma) groups. Lentil domestication led to a loss of genetic diversity of approximately 40%. The approach followed in this research has allowed us to rapidly exploit sequence information from model plant species for the study of genetic diversity of a crop such as lentil with limited genomic resources.     

Cell Selective Conditional Null Mutations of Serine Racemase Demonstrate a Predominate Localization in Cortical Glutamatergic Neurons

d-Serine, which is synthesized by the enzyme serine racemase (SR), is a co-agonist at the N-methyl-d-aspartate receptor (NMDAR). Crucial to an understanding of the signaling functions of d-serine is defining the sites responsible for its synthesis and release. In order to quantify the contributions of astrocytes and neurons to SR and d-serine localization, we used recombinant DNA techniques to effect cell type selective suppression of SR expression in astrocytes (aSRCKO) and in forebrain glutamatergic neurons (nSRCKO). The majority of SR is expressed in neurons: SR expression was reduced by ~65% in nSRCKO cerebral cortex and hippocampus, but only ~15% in aSRCKO as quantified by western blots. In contrast, nSRCKO is associated with only modest decreases in d-serine levels as quantified by HPLC, whereas d-serine levels were unaffected in aSRCKO mice. Liver expression of SR was increased by 35% in the nSRCKO, suggesting a role for peripheral SR in the maintenance of brain d-serine. Electrophysiologic studies of long-term potentiation (LTP) at the Schaffer collateral–CA1 pyramidal neuron synapse revealed no alterations in the aSRCKO mice versus wild-type. LTP induced by a single tetanic stimulus was reduced by nearly 70% in the nSRCKO mice. Furthermore, the mini-excitatory post-synaptic currents mediated by NMDA receptors but not by AMPA receptors were significantly reduced in nSRCKO mice. Our findings indicate that in forebrain, where d-serine appears to be the endogenous co-agonist at NMDA receptors, SR is predominantly expressed in glutamatergic neurons, and co-release of glutamate and d-serine is required for optimal activation of post-synaptic NMDA receptors.     

Alien plants associate with widespread generalist arbuscular mycorrhizal fungal taxa: evidence from a continental‐scale study using massively parallel 454 sequencing

Aim The biogeography of arbuscular mycorrhizal (AM) fungi is poorly understood, and consequently the potential of AM fungi to determine plant distribution has been largely overlooked. We aimed to describe AM fungal communities associating with a single host‐plant species across a wide geographical area, including the plant’s native, invasive and experimentally introduced ranges. We hypothesized that an alien AM plant associates primarily with the geographically widespread generalist AM fungal taxa present in a novel range. Location Europe, China. Methods We transplanted the palm Trachycarpus fortunei into nine European sites where it does not occur as a native species, into one site where it is naturalized (Switzerland), and into one glasshouse site. We harvested plant roots after two seasons. In addition, we sampled palms at three sites in the plant’s native range (China). Roots were subjected to DNA extraction, polymerase chain reaction (PCR) and 454 sequencing of AM fungal sequences. We analysed fungal communities with non‐metric multidimensional scaling (NMDS) ordination and cluster analysis and studied the frequency of geographically widespread fungal taxa with log‐linear analysis. We compared fungal communities in the roots of the palm with those in resident plants at one site in the introduced range (Estonia) where natural AM fungal communities had previously been studied. Results We recorded a total of 73 AM fungal taxa. AM fungal communities in the native and introduced ranges differed from one another, while those in the invasive range contained taxa present in both other ranges. Geographically widespread AM fungal taxa were over‐represented in palm roots in all regions, but especially in the introduced range. At the Estonian site, the palm was colonized by the same community of widespread AM fungal taxa as associate with resident habitat‐generalist plants; by contrast, resident forest‐specialist plants were colonized by a diverse community of widespread and other AM fungal taxa. Main conclusions AM fungal communities in the native, invasive and experimentally introduced ranges varied in taxonomic composition and richness, but they shared a pool of geographically widespread, non‐host‐specific taxa that might support the invasion of a generalist alien plant. Our dataset provides the first geographical overview of AM taxon distributions obtained using a single host‐plant species.     

Digest: Evolution of mutual ornamentation in hummingbirds*

Why are female birds ornamented? In a comparative phylogenetic study of hummingbirds (Trochilidae), Clark and Rankin tackled this crucial question and investigated how male tail evolution is reflected in female morphology.