Divergence estimates and early evolutionary history of Figitidae (Hymenoptera: Cynipoidea)

We examine the phylogenetic relationships of Figitidae and discuss host use within this group in light of our own and previously published divergence time data. Our results suggest Figitidae, as currently defined, is not monophyletic. Furthermore, Mikeiinae and Pycnostigminae are sister‐groups, nested adjacent to Thrasorinae, Plectocynipinae and Euceroptrinae. The recovery of Pycnostigminae as sister‐group to Mikeiinae suggests two major patterns of evolution: (i) early Figitidae lineages demonstrate a Gondawanan origin (Plectocynipinae: Neotropical; Mikeiinae and Thrasorinae: Australia; Pycnostigminae: Africa); and (ii) based on host records for Mikeiinae, Thrasorinae and Plectocynipinae, Pycnostigminae are predicted to be parasitic on gall‐inducing Hymenoptera. The phylogenetic position of Parnips (Parnipinae) was unstable, and various analyses were conducted to determine the impact of this uncertainty on both the recovery of other clades and inferred divergence times; when Parnips was excluded from the total evidence analysis, Cynipidae was found to be sister‐group to [Euceroptrinae + (Plectocynipinae (Thrasorinae + (Mikeiinae + Pycnostigminae)))], with low support. Divergence dating analyses using BEAST indicate the stem‐group node of Figitidae to be c. 126 Ma; the dipteran parasitoids (Eucoilinae and Figitinae), were estimated to have a median age of 80 and 88 Ma, respectively; the neuropteran parasitoids (Anacharitinae), were estimated to have a median age of 97 Ma; sternorrhynchan hyperparasitoids (Charipinae), were estimated to have a median age of 110 Ma; the Hymenoptera‐parasitic subfamilies (Euceroptinae, Plectocynipinae, Trasorinae, Mikeiinae, Pycnostigminae, and Parnipinae), ranged in median ages from 48 to 108 Ma. Rapid radiation of Eucoilinae subclades appears chronologically synchronized with the origin of their hosts, Schizophora (Diptera). Overall, the exclusion of Parnips from the BEAST analysis did not result in significant changes to divergence estimates. Finally, though sparsely represented in the analysis, our data suggest Cynipidae have a median age of 54 Ma, which is somewhat older than the age of Quercus spp (30–50 Ma), their most common host.     

Maternal prenatal depressive symptoms predict infant NR3C1 1F and BDNF IV DNA methylation

Prenatal maternal psychological distress increases risk for adverse infant outcomes. However, the biological mechanisms underlying this association remain unclear. Prenatal stress can impact fetal epigenetic regulation that could underlie changes in infant stress responses. It has been suggested that maternal glucocorticoids may mediate this epigenetic effect. We examined this hypothesis by determining the impact of maternal cortisol and depressive symptoms during pregnancy on infant NR3C1 and BDNF DNA methylation. Fifty-seven pregnant women were recruited during the second or third trimester. Participants self-reported depressive symptoms and salivary cortisol samples were collected diurnally and in response to a stressor. Buccal swabs for DNA extraction and DNA methylation analysis were collected from each infant at 2 months of age, and mothers were assessed for postnatal depressive symptoms. Prenatal depressive symptoms significantly predicted increased NR3C1 1F DNA methylation in male infants (β = 2.147, P = 0.044). Prenatal depressive symptoms also significantly predicted decreased BDNF IV DNA methylation in both male and female infants (β = −3.244, P = 0.013). No measure of maternal cortisol during pregnancy predicted infant NR3C1 1F or BDNF promoter IV DNA methylation. Our findings highlight the susceptibility of males to changes in NR3C1 DNA methylation and present novel evidence for altered BDNF IV DNA methylation in response to maternal depression during pregnancy. The lack of association between maternal cortisol and infant DNA methylation suggests that effects of maternal depression may not be mediated directly by glucocorticoids. Future studies should consider other potential mediating mechanisms in the link between maternal mood and infant outcomes.     

Phylogeny and taxonomy of the Prenolepis genus‐group of ants (Hymenoptera: Formicidae)

Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided.     

Accessory cell requirements for lymphoma growth in vitro and in irradiated mice.

Growth of the transplantable B-cell lymphoma, PU-5, is markedly diminished in γ-irradiated as compared to normal BALB/c mice. Transfer of bone marrow, but not of lymph node or peritoneal exudate cells, partially restored the ability of irradiated mice to support lymphoma growth. In vitro growth of PU-5 cells is promoted by silica-sensitive, adherent cells, bearing surface Ia antigen and present in peritoneal exudates, spleen and lymph node, but not in bone marrow. Their action on PU-5 growth can be shown only in rocking cultures; the cells do not have to be histocompatible, they act synergistically with 2-mercaptoethanol (2-ME) in the medium. The growth-promoting action in vitro is decreased 24 hr after γ-irradiation of the adherent cells in vitro. Growth of transplantable reticulum cell sarcoma in SJL/J mice has previously also been shown to be inhibited by prior irradiation of the host and to be restored by transfer of lymphoid cells including a phagocytic component, but in the present studies no consistent growth-promoting effect of accessory cells on reticulum cell sarcomas has been shown in vitro. Both lymphomas are stimulated by the presence of 2-ME in stationary cultures. The relationship between the in vivo and in vitro lymphoma growth-promoting activities of macrophage-like cells is discussed.     

Compartment boundaries: Sorting cells with tension

The subdivision of proliferating tissues into groups of non-intermingling sets of cells, termed compartments, is a common process of animal development. Signaling between adjacent compartments induces the local expression of morphogens that pattern the surrounding tissue. Sharp and straight boundaries between compartments stabilize the source of such morphogens during tissue growth and, thus, are of crucial importance for pattern formation. Signaling pathways required to maintain compartment boundaries have been identified, yet the physical mechanisms that maintain compartment boundaries remained elusive. Recent data now show that a local increase in actomyosin-based mechanical tension on cell bonds is vital for maintaining compartment boundaries in Drosophila.Key words: Drosophila, wing imaginal disc, compartment boundary, cell sorting, mechanical tensionCompartments were first identified in the wings and abdomen of insects by clonal analysis.^1,2 When single cells were genetically marked during early development, the descendant cells (‘clone’) grew up in the adult structure to a boundary line (the compartment boundary), and frequently ran along it, but never extended to the other side. These experiments revealed that, in Drosophila, the developing wing is subdivided during embryogenesis into anterior (A) and posterior (P) compartments (Fig. 1A) and later, during larval development, into dorsal (D) and ventral (V) compartments. Compartments were subsequently identified in different parts of the fly, including the leg, haltere, head and abdomen.^3–7 More recently, lineage tracing also revealed compartments in vertebrate embryos,^8–16 indicating that the formation of compartments is a common strategy during both insect and vertebrate development.Open in a separate windowFigure 1Increased cell bond tension at compartment boundaries in Drosophila. (A) The Drosophila wing imaginal disc is subdivided into anterior (A) and posterior (P) compartments. (B) Myosin II and F-actin (green lines) are enriched at the cell bonds between anterior cells and posterior cells compared to cell bonds elsewhere in the tissue. Mechanical tension (arrows) on cell bonds along the A/P boundary is increased. (C) Measurement of cell bond tension by laser ablation. Arrowheads depict the site of ablation. The two vertices at the ends of the ablated cell bond are displaced. (D and E) Sequential images of an E-cadherin-GFP-labelled cell bond within the anterior compartment (D) or at the A/P boundary (E) before and after laser ablation in wing imaginal discs. (F) Each parasegment of the Drosophila embryo is subdivided into anterior and posterior compartments. (G) Chromophore-assisted laser inactivation (CALI) to locally reduce Myosin II (green lines) in cells along the parasegment boundary (boxed area). As a consequence, dividing cells at the parasegment boundary intermingle.Meinhardt''s theoretical work on pattern formation proposed that boundaries between compartments act as reference lines for positional information during tissue development, and that they serve as sources of morphogen synthesis.^17,18 Indeed, many compartment boundaries, both in insects and vertebrates, have by now been shown experimentally to be associated with signaling centers that produce morphogens (reviewed in refs. ¹⁹ and ²⁰). The defined position and shape of signaling centers is important for the establishment of precise morphogen gradients and patterning.^21,22 In growing tissues, however, the position and shape of signaling centers is challenged by cell rearrangements that take place during cell division.^23,24 By inducing signaling centers along stable and straight compartment boundaries, precise morphogen gradients can be maintained in proliferating tissues.²⁵ Compartment boundaries therefore play vital roles during the patterning of proliferating tissues.How are straight and sharp compartment boundaries maintained despite cell re-arrangements caused by cell division? The maintenance of compartment boundaries often requires local signaling between cells from the two adjacent compartments. In the developing hindbrain, for example, signaling by Eph receptors and ephrins is required to maintain the boundaries between adjacent rhombomeres.^26,27 In the developing wing of the fly, signaling downstream of Hedgehog and Dpp is required to maintain the A/P boundary,^28–31 and Notch signaling is required to maintain the D/V boundary.^32,33 The physical mechanisms maintaining compartment boundaries, however, remained elusive for a long time. Two recent papers, by Landsberg et al. and Monier et al. now provide evidence that actomyosin-dependent tension on cell bonds is an important mechanism to maintain straight and sharp compartment boundaries.^34,35A longstanding hypothesis posed that the sorting of cells at compartment boundaries is due to differences in the affinities between cells of adjacent compartments.³⁶ Earlier theoretical work by Malcom Steinberg had indeed proposed that differences in the adhesiveness of cells lead to cell sorting.³⁷ Steinberg''s hypothesis was based on the important insight that cell sorting closely resembles the separation of immiscible liquids and that quantitative differences in cell properties suffice to explain cell sorting. Cadherins are a class of Ca²⁺-dependent cell adhesion molecules that can confer differential cell adhesion in vitro and in vivo.^38–40 Circumstantial evidence indicates that cadherins may play a role in maintaining compartment boundaries. In the telencephalon of mouse embryos, for example, the interface between cells expressing R-cadherin and cells expressing cadherin-6 coincide with the cortico-striatal compartment boundary.¹¹ Interestingly, cortical cells ectopically expressing cadherin-6 sort into the striatal compartment, and the reverse is observed for striatal cells engineered to express R-cadherin. In addition to cadherins, further cell adhesion proteins have been implicated in maintaining compartment boundaries. In the Drosophila wing imaginal disc, an epithelium that gives rise to the adult wing, the two leucine-rich-repeat domain proteins Capricious and Tartan are expressed specifically in cells of the dorsal compartment.⁴¹ Strikingly, forced expression of either of these proteins in the dorsal compartment can restore a normal straight and sharp D/V boundary in mutants for apterous, the selector gene required to establish this boundary.⁴¹More recent hypotheses to explain the sorting of cells in animal development are based on differential surface contraction⁴² or differential interfacial tension.⁴³ These hypotheses do not treat cells as liquid molecules, as Steinberg''s differential adhesion hypothesis does, but emphasize that cells can generate mechanical tension that allows them to contract the surface to neighboring cells. Minimizing cell surfaces at interfaces between different cell populations could contribute to cell sorting.Mechanical tension in cells can be generated by tensile elements located at the cellular cortex underlying the plasma membrane, including contractile actomyosin filaments (reviewed in ref. ⁴⁴). Irvine and colleagues made the important observation that, in Drosophila wing imaginal discs, Filamentous (F)-actin and the motor protein non-muscle Myosin II (Myosin II) were enriched at adherens junctions along the D/V boundary,^45,46 indicating a distinct mechanical property of bonds between cells along this compartment boundary. Moreover, these authors found that in mutants for zipper, which encodes myosin heavy chain, the D/V boundary was irregular,⁴⁶ showing a requirement for Myosin II in maintaining this boundary.Landsberg et al. show that F-actin and Myosin II were also enriched on cell bonds along the A/P boundary in Drosophila wing imaginal discs, and that also the A/P boundary was irregular in zipper mutants.³⁴ Moreover, they now provide direct evidence that mechanical tension at cell bonds along the A/P boundary is increased (Fig. 1B). Differences in mechanical tension on cell bonds have been proposed to result in differences in the shape of cells and the angles between bonds of cells.^24,47 Landsberg et al. demonstrate that the two rows of cells along the A/P boundary display a unique shape and that angles between cell bonds along the A/P boundary are widened, providing evidence that mechanical tension is elevated along these cell bonds.³⁴ Distinct shapes have also been previously reported for cells along compartment boundaries in Oncopeltus,⁴⁸ indicating that they are commonly associated with compartment boundaries.Ablation of cell bonds generates displacements of the corners (vertices) of the ablated bonds, providing direct evidence for tension on cell bonds.⁴⁹ Landsberg et al. ablated individual cell bonds in wing imaginal discs using an UV laser beam, and quantified the displacements of the two vertices of the ablated cell bonds (Fig. 1C–E). The relative initial velocities with which these vertices are separated in response to laser ablation is a relative measure of cell bond tension.⁵⁰ Ablation of cell bonds within the anterior compartment and the posterior compartment resulted in similar initial velocities.³⁴ However, when cell bonds along the A/P boundary were ablated, the initial velocity of vertex separation was approximately 2.5-fold higher.³⁴ Displacements of cell vertices after laser ablation were strongly reduced in the presence of Y-27632, a drug that specifically inhibits Rho-kinase,⁵¹ which is a major activator of Myosin II.⁵² These results suggest that actomyosin-based cell bond tension along the A/P boundary is increased 2.5-fold compared to the tension on cell bonds located elsewhere.Is a local increase in cell bond tension sufficient to maintain straight interfaces between proliferating groups of cells? To test this, Landsberg et al. simulated the growth of a tissue based on a vertex model.²⁴ In this model, the network of adherens junctions in a tissue is described by polygons characterized by the position of vertices. Stable configurations of this network are local minima of an energy function that describes the area elasticity of cells, cell bond tension, and the elasticity of cell perimeters. In these simulations, two adjacent cell populations, anterior and posterior compartments, separated by a straight and sharp interface, are introduced into this network. Tissue growth is simulated by randomly selecting a cell, increasing its area two-fold, and dividing the cell at a random angle. The energy in the whole network is then minimized and the procedure is repeated. Simulation of tissue growth renders the initially straight and sharp interface between the two compartments rough and irregular.³⁴ However, by increasing locally cell bond tension at the interface between the two simulated compartments, the interface remains straight.³⁴ These computer simulations provide evidence that a local increase in cell bond tension is sufficient to maintain straight boundaries between compartments in proliferating tissues.Monier et al. analyzed boundaries in the Drosophila embryo.³⁵ The embryonic epidermis is subdivided into parasegments, and cells from adjacent parasegments do not intermingle⁵³ (Fig. 1F). Similar to the D/V and A/P boundaries of larval wing imaginal discs, the authors found that the parasegment boundaries also display elevated levels of F-actin and Myosin II.³⁵ Injection of the Rho-kinase inhibitor Y-27632 into embryos, or expression of a dominant-negative form of zipper, resulted in cell sorting defects at the parasegment boundaries. Live imaging of embryos furthermore showed that mitotic cells locally deform the parasegment boundaries, but that the boundaries straighten out at the onset of cytokinesis. When Myosin II activity was locally reduced by chromophore-assisted laser inactivation (CALI), the parasegment boundaries failed to straighten out after cells had divided, and anterior and posterior cells partially intermingled³⁵ (Fig. 1G). These results demonstrate an important role for Myosin II in separating anterior and posterior cells at parasegment boundaries.Cell sorting is a general phenomenon of developing animals not restricted to compartment boundaries. A well-studied example is the sorting out of cells from the different germ layers during gastrulation. Interestingly, during zebrafish gastrulation, differential actomyosin-dependent cell-cortex tension has recently been implicated in the sorting out of cells from different germ layers.⁵⁴ A differential mechanical tension might, therefore, be a general mechanism to prevent the mixing of cells in developing animals.Does differential cell adhesion play a role in regulating mechanical tension? At least two contributions can be envisioned. First, cell bond tension depends on both contractile forces along cell bonds as well as the strength of adhesion between neighboring cells.^24,43 Elevating contractile forces can increase cell bond tension, whereas increasing adhesive contacts between cells can release tension. Differences in the adhesion between neighboring cells along compartment boundaries, compared to the remaining cells within the compartments, could therefore contribute to the maintenance of compartment boundaries. Second, differential expression of some cell adhesion molecules results in a local increase of F-actin and Myosin II. For example, interfaces between cells expressing the cell adhesion molecule Echinoid and cells lacking Echinoid display elevated levels of F-actin and Myosin II in Drosophila wing imaginal discs.⁵⁵ Therefore, it seems plausible that, at least in some cases, the increase of F-actin and Myosin II at compartment boundaries could be the consequence of the differential expression of adhesion molecules. In this model, differential cell adhesion would play an indirect role in maintaining compartment boundaries by resulting in local enrichment of F-actin and Myosin II, which in turn could lead to an elevated mechanical tension.The local enrichment of F-actin and Myosin II at distinct sites within cells, and a presumed modulation of tensile stresses, is not restricted to compartment boundaries, but appears to be common to diverse developmental processes. In gastrulating Drosophila embryos, for example, tissue elongation is driven by cell intercalation that depends on the enrichment of Myosin II on shrinking cell bonds.^56,57 Similarly, during mesoderm invagination of Drosophila embryos, F-actin and Myosin II accumulate in a central weblike structure at the apical side of cells resulting in apical cell constriction.⁵⁸ Recruitment of F-actin and Myosin II to this medial web can be induced by expression of an activated form of Wasp, a known regulator of actin polymerization, providing a mechanism for the local enrichment of actomyosin within cells.⁵⁹ In addition to biochemical mechanisms, mechanical signals have also been shown to help localize Myosin II to specific sites within cells. During germband elongation in the Drosophila embryo, for example, cell bonds that are under high tension have elevated levels of Myosin II, and the experimental application of mechanical force is sufficient to recruit Myosin II to the cell cortex.⁶⁰ Increased tension at cell bonds along compartment boundaries might, therefore, be also a consequence of both biochemical and mechanical mechanisms. It will be interesting to investigate the nature of these mechanisms, and how they are linked to the developmental signals that control the formation of compartment boundaries.     

The TIM gene family: emerging roles in immunity and disease

The search for cell-surface markers that can distinguish T helper 1 (T(H)1) cells from T(H)2 cells has led to the identification of a new gene family, encoding the T-cell immunoglobulin mucin (TIM) proteins, some of which are differentially expressed by T(H)1 and T(H)2 cells. The role of the TIM-family proteins in immune regulation is just beginning to emerge. Here, we describe the various TIM-family members in mice and humans, and discuss the genetic and functional evidence for their role in regulating autoimmune and allergic diseases.     

RETRACTED: SENSORY SUGGESTIVENESS AND LABELING: DO SOY LABELS BIAS TASTE?1

Can labels suggestively influence sensory perceptions and taste? Using a “ Phantom Ingredient” taste test, we show that the presence or absence of a labeled ingredient (soy) and the presence or absence of a health claim negatively bias taste perceptions toward a food erroneously thought to contain soy. We found a label highlighting soy content made health claims believable but negatively influenced perceptions of taste for certain segments of consumers. Our results and discussion provide better direction for researchers who work with ingredient labeling as well as for those who work with soybean products.     

Promotion of plantlet formation from somatic embryos of carrot treated with a high molecular weight extract from a marine cyanobacterium

Summary Somatic embryos of Daucus carota L. developed into plantlets at high frequency after addition of an extract from a marine cyanobacterium, Synechococcus sp. NKBG 042902. High molecular weight, nondialyzing fraction, separated from the extract, possessed enhanced plantlet formation promoting activity. Plantlet formation frequency was 60 % after addition of nondialysate (100 mg/l) compared to 28 % without addition. Embryos treated with the nondialysate contained five times more chlorophyll than nontreated embryos after 6 days of culture. The chlorophyll a/b ratio of 4-day old treated somatic embryos was found to be similar to that of zygotic embryos. However, the chlorophyll a/b ratio of plantlets induced from nontreated somatic embryos was variable. Nondialysate was fractionated by ultracentrifugation and an active component obtained, which gave a maximum plantlet formation frequency of 71 %, and induced rapid greening of shoots.Abbreviations MS Murashige and Skoog medium - 2,4D 2,4-dichlorophenoxyacetic acid - PCV packed cell volume - E Einstein - Chl Chlorophyll - vvm volume of air, volume of medium per minute     

Effects of Maillard reaction products on the oxidative cleavage and polymerization of protein under ascorbic acid-transition metal system.

This study investigated the effects of Maillard reaction products (MRPs) on the oxidative cleavage and polymerization of BSA (bovine serum albumin) in an aqueous system. In L-ascorbic acid (AsA) and Cu(II) or Fe(III) reaction system, 50-60% of BSA was cleaved under physiological conditions (37 degrees C, pH 7.2). The oxidative cleavage induced by AsA-Cu(II) system was suppressed to the extent of 32-86% by model melanoidins or brown pigments from amino acids and foodstuffs. In the AsA-Fe(III) system, the oxidative cleavage was inhibited to the extent of 45-93% by melanoidins and brown pigments. However, this cleavage was promoted by amino acid Amadori rearrangement products and brown pigment from soy paste. Therefore, MRPs show both suppression and promotion activity on oxidative cleavage of BSA in the system of AsA and a transition metal. The quantity of Amadori rearrangement moiety (ARM) in melanoidins from Lysine and brown pigments molecules from foods was also measured. From these data, it was estimated that the suppression and/or promotion of oxidative cleavage of BSA did not only depend on the quantity of ARM, but also depended on the chemical structure of ARM in melanoidins or brown pigments.