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PubMed2006

Effects of temephos and temperature on Wolbachia load and life history traits of Aedes albopictus.

Maternally inherited Wolbachia (gram-negative bacteria) often affect the reproductive fitness of their arthropod hosts and may cause cytoplasmic incompatibility (CI). Comparing Wolbachia-infected and uninfected strains of the mosquito Aedes albopictus (Skuse) (Diptera: Culicidae), we assessed the effects on fitness of two stressors: temperature elevation (25 degrees C vs. 37 degrees C) and exposure to temephos insecticide (concentration range 0.0017-0.0167 mg/L) during larval development. Fitness was measured in terms of life history traits: percentage survival, development time and wing size. Insecticide treatment was associated with reduction in survival rates and wing size in both sexes, but did not affect development time or Wolbachia load. Temperature elevation by 12 degrees C significantly reduced all four bionomic parameters observed in both sexes. Wolbachia density within individual adult mosquitoes was determined by using real-time quantitative polymerase chain reaction (PCR) based on the wsp gene. Both male and female adults had significantly lower densities of Wolbachia after larval rearing at the higher temperature.

Aedes↗
PubMed2002

Cloning of zebrafish T-box genes tbx15 and tbx18 and their expression during embryonic development.

Members of the T-box (tbx) gene family encode developmentally regulated transcription factors, several of which are implicated in human hereditary diseases. We have cloned the paralogous genes tbx15 and tbx18 in zebrafish and have characterised their expression in detail. tbx15 is expressed in paraxial head mesenchyme and its derivatives, the extraocular and jaw musculature and the posterior neurocranium. Further areas of tbx15 expression are in the anterior somitic mesoderm, in periocular mesenchyme and in the pectoral fin mesenchyme throughout larval development. Areas of strong tbx18 expression are found in the developing somitic and presomitic mesoderm, in the heart and in pectoral fin mesenchyme, as well as the ventral neuroectoderm and the developing palate. Both genes exhibit particular differences in expression compared to their murine orthologs.

Amino Acid Sequence↗
PubMed1995

A novel glycoprotein in the olfactory and pituitary systems of larval and adult lampreys.

A novel homodimeric glycoprotein was isolated and characterized from the pituitaries of adult sea lampreys, Petromyzon marinus, modern representatives of the earliest vertebrates. The monomer consists of 121 amino-acid residues in a sequence that has no resemblance to any known pituitary hormone. Whereas this protein is localized in most cells of the rostral pars distalis of adult lampreys, we have chosen to name it, nasohypophysial factor (NHF), because it first appears in the olfactory system of developing larval lampreys. Not only may NHF be a new pituitary hormone but a useful probe for examining the ontogenetic and phylogenetic relationships of the pituitary and olfactory systems in vertebrates.

Amino Acid Sequence↗
PubMed1989

The emergence of order in the Drosophila pupal retina.

During pupation, long-range order is imposed on the autonomously developing ommatidia which compose the Drosophila eye. To accomplish this, eight additional cell types arise: the primary, secondary, and tertiary pigment cells, and the four cells that form the bristle. These cells form an interweaving lattice between ommatidia. The lattice is refined when excess cells are removed to bring neighboring ommatidia into register. Recent evidence suggests that in larval development, local contacts direct cell fate. The same appears to be true during pupal development: the contacts a cell makes predict the cell type it will become. Cells which contact the anterior or posterior cone cells in an ommatidium invariably become primary pigment cells. Cells which contact primary pigment cells from different ommatidia become secondary and tertiary pigment cells. Bristle development is in several ways distinct from ommatidial development. The four cells of each bristle group appear to be immediate descendents of a single founder cell. During their early differentiation, they do not make stereotyped contacts with surrounding ommatidial cells, but do make particular contacts within the bristle group. And unlike the surrounding ommatidia, differentiation of the bristles radiates from the center of the eye to the edges. As cells are removed during two stages of programmed cell death, the bristles are brought into their final position. When all cells in the lattice have achieved their final position, a second stage of retinal development begins as structures specific to each cell type are produced. This paper follows these various stages of pupal development, and suggests how local cell-cell contacts may produce the cells needed for a functional retina.

Animals↗
PubMed2000

Temperature tolerance of the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae) in tropical and temperate regions of Asia.

Temperature tolerance was investigated in nine populations of Plutella xylostella Linnaeus from tropical and temperate regions of Asia. At all rearing temperatures between 15 and 35 degrees C, no clear differences were observed in female egg production or larval development between tropical and temperate populations. Thus, tropical populations did not show a high-temperature tolerance superior to that of the temperate populations. In all populations, the net reproductive rate (number of new females born per female) largely depended on the number of eggs laid per female, and egg production significantly decreased with increasing temperature (P < 0.001). Larval developmental rate also showed a significant positive correlation with temperature (P < 0.001). Per cent hatch of eggs and larval survival did not show a significant correlation with temperature: hatching was constant between 15 and 32.5 degrees C, but considerably lower at 35 degrees C. Larval survival was similar between 15 and 30 degrees C, appreciably lower at 32.5 degrees C and declined to 0% at 35 degrees C. Based on these results, environmental conditions under which P. xylostella can maintain a high population density throughout the year in tropical and subtropical regions are discussed.

Animals↗
PubMed2002

Neuropilin-1 is required for vascular development and is a mediator of VEGF-dependent angiogenesis in zebrafish.

Neuropilin-1 (NRP1) is a cell-surface receptor for both vascular endothelial growth factor(165) (VEGF(165)) and class 3 semaphorins that is expressed by neurons and endothelial cells. NRP1 is required for normal developmental angiogenesis in mice. The zebrafish is an excellent system for analyzing vascular development. Zebrafish intersegmental vessels correspond to mammalian capillary sprouts, whereas the axial vessels correspond to larger blood vessels, such as arteries. The zebrafish NRP1 gene (znrp1) was isolated and when overexpressed in cells, zNRP1 protein was a functional receptor for human VEGF(165). Whole-mount in situ hybridization showed that transcripts for znrp1 during embryonic and early larval development were detected mainly in neuronal and vascular tissues. Morpholino-mediated knockdown of zNRP1 in embryos resulted in vascular defects, most notably impaired circulation in the intersegmental vessels. Circulation via trunk axial vessels was not affected. Embryos treated with VEGF receptor-2 kinase inhibitor had a similar intersegmental vessel defect suggesting that knockdown of zNRP1 reduces VEGF activity. To determine whether NRP1 and VEGF activities were interdependent in vivo, zNRP1 and VEGF morpholinos were coinjected into embryos at concentrations that individually did not significantly inhibit blood vessel development. The result was a potent inhibition of blood cell circulation via both intersegmental and axial vessels demonstrating that VEGF and NRP1 act synergistically to promote a functional circulatory system. These results provide the first physiological demonstration that NRP1 regulates angiogenesis through a VEGF-dependent pathway.

Animals↗
PubMed1984

Purification and subunit structure of RNA polymerase II from different stages of Artemia development.

RNA polymerase II has been purified from different stages of Artemia development: cryptobiotic gastrulae, developing embryos and nauplii. RNA polymerase from dormant and developing embryos consists of 12 subunits of 205 000, 140 000, 32 500, 25 600, 22 000, 19 400, 18 000, 16 800, 147 000, 14 000, 12 700 and 11 500 daltons, as determined by dodecyl sulphate polyacrylamide gel electrophoresis. The enzyme from larvae contains the same polypeptides except for the higher-molecular-mass component: the larval enzyme has a subunit of 172 kDa instead of the 205-kDa subunit present in the enzyme purified from embryos. Incubation of embryonic RNA polymerase II with larval extracts results in the conversion of the 205-kDa subunit into the 172-kDa one. This conversion is inhibited by soybean trypsin inhibitor, a compound which inhibits three proteases induced during Artemia early larval development. RNA polymerase II purified from a mixture of embryos and larvae contain only the 172-kDa subunit. Our results indicate that the 172-kDa subunit present in RNA polymerase II purified from larvae is produced by proteolysis of the 205-kDa subunit during the extraction and purification of the enzyme and therefore that Artemia has only one class of RNA polymerase II.

Animals↗
PubMed2004

Reproduction and development of the conspicuously dimorphic brittle star Ophiodaphne formata (Ophiuroidea).

Ophiodaphne formata is a conspicuously dimorphic ophiuroid; the disk diameters are approximately 1 mm for males and 5 mm for females. The dwarf male clings to the larger female, with the oral surfaces and bursae of the paired ophiuroids closely appressed. Moreover, the female of each pair adheres aborally to the oral surface of a host sand dollar, Astriclypeus manni. Spawning and external fertilization occur in August, at Tsuruga Bay, Sea of Japan. Development of the dimorphic brittle star O. formata is described for the first time, from spawning through metamorphosis, with special attention to the formation of the skeletal system and the external morphology of early juveniles. Fertilized eggs are about 90 microm in diameter, pale pink, and negatively buoyant. The embryos undergo equal, total, and radial cleavage, and the larval skeleton first forms as a pair of tetraradiate spicules. Larval development proceeds to an 8-armed planktotrophic ophiopluteus, with skeletal elements that consist of a body rod and two recurrent rods. Three weeks after fertilization, all the pluteal arms, except for the postero-lateral arms, are absorbed, and the metamorphosing larvae sink to the bottom. Metamorphosis is completed 21.5 days after fertilization, and the resulting juvenile is pentagonal and approximately 270 microm in diameter. The smallest specimen (480 microm in disk diameter) collected by field sampling exhibited male features on the skeletal plates of the jaw and disk. Sexual dimorphism, the peculiar pairing behavior, and the close relationship with the host sand dollar may have evolved as distinct reproductive characteristics in this ophiuroid with its typical ophiopluteus larvae.

Animals↗
PubMed2005

Development and reproduction of Adalia bipunctata (Coleoptera: Coccinellidae) on eggs of Ephestia kuehniella (Lepidoptera: Phycitidae) and pollen.

Due to growing criticism over the use of non-indigenous coccinellids, the two-spot ladybird, Adalia bipunctata (L.), has enjoyed increasing attention for aphid biocontrol in Europe. In the current study, eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, whether or not supplemented with bee pollen, were evaluated as a factitious food for larvae and adults of A. bipunctata. The predator showed slower larval development and lower survival when reared on live pea aphids, Acyrthosiphon pisum (Harris), than on E. kuehniella eggs. Survival on gamma-irradiated eggs of E. kuehniella was superior to that on frozen flour moth eggs, but other developmental characteristics were similar. Adults of A. bipunctata reared on Ac. pisum were only half as fecund as those offered irradiated or frozen E. kuehniella eggs, but egg hatch was markedly better on live aphids than on flour moth eggs (61 versus 20-27%, respectively). However, when a diet of flour moth eggs was supplemented with frozen moist bee pollen, egg hatch of A. bipunctata was equally as good as on live aphids. Supplementing flour moth eggs with dry pollen did not yield satisfactory results. Only 10% of larvae reached adulthood on moist bee pollen alone and resulting adults weighed less than half as much as those obtained on flour moth eggs. Our findings indicate that A. bipunctata is able to compensate for a suboptimal diet of animal prey by supplementary feeding on flower pollen. It is concluded that pollinivory may be a crucial trait for both the rearing of this natural enemy and its use in biological control programmes.

Animals↗
PubMed2004

Effects of raised CO2 concentration on the egg production rate and early development of two marine copepods (Acartia steueri and Acartia erythraea).

Direct injection of CO(2) into the deep ocean is receiving increasing attention as a way to mitigate increasing atmospheric CO(2) concentration. To assess the potential impact of the environmental change associated with CO(2) sequestration in the ocean, we studied the lethal and sub-lethal effects of raised CO(2) concentration in seawater on adult and early stage embryos of marine planktonic copepods. We found that the reproduction rate and larval development of copepods are very sensitive to increased CO(2) concentration. The hatching rate tended to decrease, and nauplius mortality rate to increase, with increased CO(2) concentration. These results suggest that the marine copepod community will be negatively affected by the disposal of CO(2). This could decrease on the carbon export flux to the deep ocean and change the biological pump. Clearly, further studies are needed to determine whether ocean CO(2) injection is an acceptable strategy to reduce anthropogenic CO(2).

Animals↗
PubMed1997

Trichinosis.

Trichinosis is a worldwide zoonotic disease closely related to cultural and dietary habits caused by a nematode Trichinella spp. Human infection is acquired through ingestion of undercooked meat containing infective encysted larvae. There are two cycles of transmission, one domestic and the other wild. A complete life cycle develops in a single host harboring adult worms in the small intestine, from which newborn larvae migrate and finally encyst in striated muscle. Traumatic and immunological alterations are responsible for the main clinical features, including diarrhea, febrile syndrome, myalgias, oculopalpebral signs and eosinophilia. Cardiovascular, lung and CNS involvement characterize severe trichinosis. CNS inflammatory infiltration and damage may result from larval migration and vascular obstruction, or from the effect of toxic parasite antigens, or eosinophil infiltration. Humoral and cellular immune host response are relevant both to protect against re-infection and for immunodiagnosis. DNA probes and PCR technology may help to identify Trichinella spp. Muscle biopsy may disclose T spiralis larvae coiled within a muscle fibre host nurse cell surrounded by a capsule. Inflammatory infiltration includes monocytes, plasma cells, eosinophils and T lymphocytes mainly of the suppressor/cytotoxic phenotype. Histological appearance and histochemical profile of the host nurse cell differ from that of striated muscle fibre and are partly indicative of regeneration. Our own histological and histochemical findings in experimental studies of infected mouse muscle support the concept that changes induced by the larva encysting within a single host skeletal muscle fibre which becomes a nurse cell are unique of Trichinella infection. Interestingly, no dystrophin could be detected within the host nurse cell-capsule interface. It has been advanced that larva-induced host muscle fibre changes may be regulated at muscle gene transcription level whilst host regulatory pathways governed by cell cycle phase may also contribute to larval development.

Animals↗
PubMed2005

Effect of nature of dietary lipids on European sea bass morphogenesis: implication of retinoid receptors.

The effect of the nature and form of supply of dietary lipids on larval development was investigated in European sea bass larvae, by considering the expression of several genes involved in morphogenesis. Fish were fed from 7 to 37 d post-hatch with five isoproteic and isolipidic compound diets incorporating different levels of EPA and DHA provided by phospholipid or neutral lipid. Phospholipid fraction containing 1.1 % (PL1 diet) to 2.3 % (PL3 diet) of EPA and DHA sustained good larval growth and survival, with low vertebral and cephalic deformities. Similar levels of EPA and DHA provided by the neutral lipid fraction were teratogenic and lethal. Nevertheless, dietary phospholipids containing high levels of DHA and EPA (PL5 diet) induced cephalic (8.5 %) and vertebral column deformities (35.3 %) adversely affecting fish growth and survival; moreover, a down-regulation of retinoid X receptor alpha (RXRalpha), retinoic acid receptor alpha, retinoic acid receptor gamma and bone morphogenetic protein-4 genes was also noted in PL5 dietary group at day 16. High levels of dietary PUFA in neutral lipid (NL3 diet) first up-regulated the expression of RXRalpha at day 16 and then down-regulated most of the studied genes at day 23, leading to skeletal abnormalities and death of the larvae. A moderate level of PUFA in neutral lipids up-regulated genes only at day 16, inducing a lesser negative effect on growth, survival and malformation rate than the NL3 group. These results showed that retinoid pathways can be influenced by dietary lipids leading to skeletal malformation during sea bass larvae development.

Animals↗
PubMed2005

Ontogeny of osteonectin expression in embryos and larvae of sea bream (Sparus auratus).

Osteonectin (OSN) is a glycoprotein which is implicated in development, bone formation and mineralisation, tumorigenesis, angiogenesis, and wound healing. Regulation of its expression by hormones may be one of the mechanisms by which the endocrine system affects bone metabolism. As a first step to understanding OSN function in fish, the gene expression of the recently cloned cDNA for sea bream, Sparus auratus, osteonectin (sbOSN) was characterised during embryonic and larval development. sbOSN mRNA was first detected by semi-quantitative reverse transcription-polymerase chain reaction in embryos at early gastrula and its expression increased continuously until hatch, after which it decreased until 15 days post-hatch (dph), increased transiently until 24 dph and decreased thereafter. In situ hybridisation showed it had a differential tissue distribution which was age dependent. In general, sbOSN mRNA was identified in cartilaginous and calcified structures of both dermal and endochondral origin but its expression was not restricted to the skeleton. sbOSN transcripts were also detected in the skin, perichordal sheath, nerve cord, and kidney tubules.

Aging↗
PubMed1991

Effect of larval diet on cat flea (Siphonaptera: Pulicidae) developmental times and adult emergence.

The natural diet of cat flea, Ctenocephalides felis (Bouche), larvae is primarily adult flea feces, but dried bovine blood may be substituted in the laboratory. Percentage adult emergence (79.4% on feces; 78.9% on blood) and developmental times (20.6 d on feces; 17.1 d on blood) did not significantly differ for the two diets. The drying temperature of blood determined its quality; blood dried at 120 degrees C was unsatisfactory for larval development. The dietary value of dried bovine blood was not enhanced when supplemented with brewer's yeast, rodent chow, or a combination of those constituents. Blood particle size ranging from less than 180 to greater than 500u did not affect the value of blood as a diet. Rodent chow, yeast, albumen, hemoglobin, and mixtures of these constituents were unsuitable as larval diets.

Animals↗
PubMed2005

Expression of COPI components during development of Drosophila melanogaster.

In a P{lArB} enhancer detector collection, a line was found that showed upregulated expression within centrally to posteriorly located germarial cysts. It was inserted in the gammaCOP locus on chromosome 3R. GammaCOP is a component of the COPI coatomer involved in membrane traffic. Most of the other known components of the COPI coatomer also showed higher expression in the posterior half of the germarium. Not only meiotic germline cysts but also migrating follicle cells upregulate the COPI subunits. During embryonic and larval development, the COPI subunits are expressed ubiquitously as expected for genes required for cell viability. In addition, they are strongly expressed in the salivary glands and the proventriculus. Whether tissue-specific transcriptional upregulation of COPI subunits is required for the reorganization of membranous compartments that are needed for the developmental processes that confer cyst polarity and follicle maturation will have to be addressed in a genetic study.

Amino Acid Sequence↗
PubMed1999

A Caenorhabditis elegans homologue of hunchback is required for late stages of development but not early embryonic patterning.

We have cloned a Caenorhabditis elegans homologue of the Drosophila gap gene hunchback (hb) and have designated it hbl-1 (hunchback-like). hbl-1 encodes a predicted 982-amino-acid protein, containing two putative zinc-finger domains similar to those of Drosophila Hunchback. The gene is transcribed embryonically, but unlike the maternally expressed Drosophila hb, its mRNA is not detected in C. elegans oocytes. A hbl-1::gfp reporter is expressed primarily in ectodermal cells during embryonic and larval development. Double-stranded RNA-interference (RNAi) was used to indicate hbl-1 loss-of-function phenotypes. Progeny of hbl-1(RNAi) hermaphrodites exhibit a range of defects; the most severely affected progeny arrest as partially elongated embryos or as hatching, misshapen L1 larvae. Animals that survive to adulthood exhibit variably dumpy (Dpy), uncoordinated (Unc), and egg-laying defective (Egl) phenotypes, as well as defects in vulval morphology (Pvl). Abnormal organization of hypodermal cells and expression of a hypodermal marker in hbl-1(RNAi) animals suggests that most of the phenotypes observed could be due to improper specification of hypodermal cells. The pattern of hbl-1 expression is similar to that reported for the leech hunchback homologue Lzf-2, suggesting that these proteins may have similar biological functions in diverse species with cellular embryos.

Amino Acid Sequence↗
PubMed1999

Distinct and regulated activities of human Gli proteins in Drosophila.

In both vertebrates and Drosophila, limb development is organized by a posteriorly located source of the signalling protein Hedgehog (Hh) [1] [2] [3] [4]. In Drosophila, the expression of Hh target genes is controlled by two opposing activities of the transcriptional regulator Cubitus interruptus (Ci), which activates target genes in response to Hh signalling but is converted into a repressor form in the absence of Hh [5] [6] [7] [8] [9] [10]. Three homologs of Ci (Gli1, Gli2, and Gli3) have been implicated in mediating responses to Sonic hedgehog (Shh) in vertebrates [11] [12]. Much attention has been devoted to the expression pattern of GLI genes; GLI1 is induced by Shh, whereas GLI3 transcription appears to be repressed by Shh signalling [13] [14] [15]. The regulation of GLI gene expression is therefore one important mechanism by which GLI genes organize pattern. It is not well understood, however, whether Shh signalling also controls the activities of Gli proteins post-translationally and whether these activities have activating or repressing effects on target genes in vivo. Here, we have subjected the human proteins Gli1 and Gli3 to the precise and well-defined Hh signalling assay of Drosophila wing development and established that Gli1 functions as an activator and Gli3 as a repressor of Hh target genes; that the activating transcriptional activity of Gli1 and the repressing activity of Gli3 are both subject to Hh regulation in vivo; and that the combined activities of Gli1 and Gli3 can substitute for Ci in controlling Hh target gene expression during embryonic and larval development.

Animals↗
PubMed1997

Genes that guide growth cones along the C. elegans ventral nerve cord.

During nervous system development, growth cone pioneering and fasciculation contribute to nerve bundle structure. Pioneer growth cones initially navigate along neuroglia to establish an axon scaffold that guides later extending growth cones. In C. elegans, the growth cone of the PVPR neuron pioneers the left ventral nerve cord bundle, providing a path for the embryonic extensions of the PVQL and AVKR growth cones. Later during larval development, the HSNL growth cone follows cues in the left ventral nerve cord bundle provided by the PVPR and PVQL axons. Here we show that mutations in the genes enu-1, fax-1, unc-3, unc-30, unc-42 and unc-115 disrupt pathfinding of growth cones along the left ventral nerve cord bundle. Our results indicate that unc-3 and unc-30 function in ventral nerve cord pioneering and that enu-1, fax-1, unc-42 and unc-115 function in recognition of the PVPR and PVQL axons by the AVKR and HSNL growth cones.

Animals↗