First described fossil representatives of the parasitoid wasp taxa Asaphesinae n. n. and Eunotinae (Hymenoptera: Chalcidoidea: Pteromalidae sensu lato) from Eocene Baltic amber

ABSTRACT

New Baltic amber species of Pteromalidae sensu lato are described, from two different subfamilies, Asaphesinae n. n. and Eunotinae. Asaphesinae is provided as a replacement name for Asaphinae Ashmead 1904, which is a junior homonym of the trilobite family Asaphidae Burmeister 1843. Coriotela lasallei gen. n., sp. n.. and Butiokeras costae gen. n., sp. n.. are described as the first known fossil species of Asaphesinae and Eunotinae, respectively. These species establish the minimum known age of both groups in the Eocene. Taxonomic changes are also proposed for some extant species. The genus Desantisiana Neder de Román syn. n.. is found to be a junior synonym of Notoglyptus, and its only described species is transferred as Notoglyptus jujuyensis (Neder de Román) comb. n.. The tribe Calyconotiscini, previously classified in Eunotinae, is abolished and Calyconotiscus Narendran & Saleem is transferred to Pireninae.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:7A107FF9-28E7-40AA-8A9B-71321E476C07     

Irs-2 coordinates Igf-1 receptor-mediated beta-cell development and peripheral insulin signalling.

Insulin receptor substrates (Irs proteins) mediate the pleiotropic effects of insulin and Igf-1 (insulin-like growth factor-1), including regulation of glucose homeostasis and cell growth and survival. We intercrossed mice heterozygous for two null alleles (Irs1+/- and Irs2+/-) and investigated growth and glucose metabolism in mice with viable genotypes. Our experiments revealed that Irs-1 and Irs-2 are critical for embryonic and post-natal growth, with Irs-1 having the predominant role. By contrast, both Irs-1 and Irs-2 function in peripheral carbohydrate metabolism, but Irs-2 has the major role in beta-cell development and compensation for peripheral insulin resistance. To establish a role for the Igf-1 receptor in beta-cells, we intercrossed mice heterozygous for null alleles of Igf1r and Irs2. Our results reveal that Igf-1 receptors promote beta-cell development and survival through the Irs-2 signalling pathway. Thus, Irs-2 integrates the effects of insulin in peripheral target tissues with Igf-1 in pancreatic beta-cells to maintain glucose homeostasis.     

IRS-2 pathways integrate female reproduction and energy homeostasis

Severe dietary restriction, catabolic states and even short-term caloric deprivation impair fertility in mammals. Likewise, obesity is associated with infertile conditions such as polycystic ovary syndrome. The reproductive status of lower organisms such as Caenorhabditis elegans is also modulated by availability of nutrients. Thus, fertility requires the integration of reproductive and metabolic signals. Here we show that deletion of insulin receptor substrate-2 (IRS-2), a component of the insulin/insulin-like growth factor-1 signalling cascade, causes female infertility. Mice lacking IRS-2 have small, anovulatory ovaries with reduced numbers of follicles. Plasma concentrations of luteinizing hormone, prolactin and sex steroids are low in these animals. Pituitaries are decreased in size and contain reduced numbers of gonadotrophs. Females lacking IRS-2 have increased food intake and obesity, despite elevated levels of leptin. Our findings indicate that insulin, together with leptin and other neuropeptides, may modulate hypothalamic control of appetite and reproductive endocrinology. Coupled with findings on the role of insulin-signalling pathways in the regulation of fertility, metabolism and longevity in C. elegans and Drosophila, we have identified an evolutionarily conserved mechanism in mammals that regulates both reproduction and energy homeostasis.     

A first phylogenomic hypothesis for Eulophidae (Hymenoptera,Chalcidoidea)

ABSTRACT

Eulophidae is a hyper-diverse family of chalcidoid wasps with 324 genera, about 5300 described species and probably thousands of others to be described. Until now, the absence of unequivocal morphological apomorphies and the low resolution provided by the handful of Sanger sequenced genes have hampered the reconstruction of phylogenetic relationships within the family. Here, we used ultra-conserved elements and their flanking regions to resolve relationships among 84 species of eulophids included in 63 genera representing all subfamilies and most tribes, plus 15 outgroups. Our analyses recover all traditional Eulophidae subfamilies and tribes with high support and globally agree with the traditional classification of the family. Our results confirm that Eulophinae + Tetrastichinae is the sister group of (Opheliminae + Entiinae) + Entedoninae. At the generic level, our analyses provide high support for intergeneric relationships for which morphology and Sanger markers previously failed to provide resolution. Our results also confirm that Trisecodes does not group with Eulophidae and may not belong to this family; however, its correct classification still awaits a large-scale phylogenomic hypothesis for Chalcidoidea. This work opens new avenues towards a better understanding of the evolutionary history, biogeography and evolution of host–parasitoid associations in this hyper-diverse family of chalcidoid wasps.     

Analysis of human T-lymphotrophic virus sequences in multiple sclerosis tissue

Several observations suggest that retroviral infection is involved in the pathogenesis of the human demyelinating disease multiple sclerosis (MS). First, lymphadenopathy-associated virus/human T-lymphotropic virus type III (LAV/HTLV-III), the agent of acquired immune deficiency syndrome (AIDS), has been shown to be neurotropic in man. Second, the genetic organization of the lentivirus visna, which causes a chronic demyelinating disease of sheep, closely resembles that of LAV/HTLV-III. Recently, Koprowski and colleagues reported that MS is associated both with raised levels of circulating antibodies to HTLV-I and with the presence of HTLV-I-specific RNA within cell lines derived from the cerebrospinal fluid (CSF). Here we report that no HTLV-I-like or LAV/HTLV-III-like sequences can be detected, by in situ hybridization, in central nervous system (CNS) tissues from MS patients, and that nonspecific HTLV-I-like signal in peripheral blood mononuclear cells or in CSF cell lines is characteristic of MS. Furthermore, enzyme-linked immunosorbent assay (ELISA) analysis of circulating and CSF antibodies for HTLV-I reactivity fails to distinguish between MS and control groups.