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At least 955 records · Page 53Linked to original sources
PubMed2005

Some morphological aspects of Wuchereria bancrofti uterus after treatment with diethylcarbamazine.

Confocal and EM analyses revealed that some female Wuchereria bancrofti, obtained from volunteers that received recommended diethylcarbamazine dose regimens, showed few or no embryos. Furthermore, inside the gravid uterus of female W. bancrofti treated with DEC we observed a finely granular, electron-dense material organised as strings of pearls, approximately 70 nm in maximal length surrounding intra-uterine microfilariae and apparently secreted by the embryo. Over the eggshells a similar material was also observed, possibly secreted by the uterine wall. The surface of intra-uterine microfilariae presented a material with identical electron-density to the scattered structures observed inside the egg. Similarly, the sheath of blood microfilariae of W. bancrofti also showed electron-dense projections, with shape and size similar to that observed inside the uterus.

Animals↗
PubMed2005

Juxtaposition between two cell types is necessary for dorsal appendage tube formation.

The Drosophila egg chamber provides an excellent model for studying the link between patterning and morphogenesis. Late in oogenesis, a portion of the flat follicular epithelium remodels to form two tubes; secretion of eggshell proteins into the tube lumens creates the dorsal appendages. Two distinct cell types contribute to dorsal appendage formation: cells expressing the rhomboid-lacZ (rho-lacZ) marker form the ventral floor of the tube and cells expressing high levels of the transcription factor Broad form a roof over the rho-lacZ cells. In mutants that produce defective dorsal appendages (K10, Ras and ectopic decapentaplegic) both cell types are specified and reorganize to occupy their stereotypical locations within the otherwise defective tubes. Although the rho-lacZ and Broad cells rearrange to form a tube in wild type and mutant egg chambers, they never intermingle, suggesting that a boundary exists that prevents mixing between these two cell types. Consistent with this hypothesis, the Broad and rho-lacZ cells express different levels of the homophilic adhesion molecule Fasciclin 3. Furthermore, in the anterior of the egg, ectopic rhomboid is sufficient to induce both cell types, which reorganize appropriately to form an ectopic tube. We propose that signaling across a boundary separating the rho-lacZ and Broad cells choreographs the cell shape-changes and rearrangements necessary to transform an initially flat epithelium into a tube.

Alleles↗
PubMed2004

Gender-associated gene expression in two related strains of Schistosoma japonicum.

Host inflammatory responses directed against eggs laid by sexually-mature Schistosoma japonicum female worms instigate lesion formation and associated clinical pathologies during infection. To identify parasite gene transcripts that associate with egg production and to characterise sexually-mature adult gene expression profiles of two related Chinese strains, S. japonicum cDNA microarrays were fabricated using 457 ESTs originating from three parasite developmental stages. Twenty-two female-associated and 8 male-associated gene transcripts were identified in the adult Anhui strain whereas 21 female-associated and 7 male-associated gene transcripts were revealed in the adult Zhejiang strain. RT-PCR analysis, in situ enzyme localisation studies and enzymatic assays confirmed the cDNA microarray results, and importantly, provided information previously unappreciated in schistosome conjugal biology. Specifically, our novel findings include the female-specific expression of genes putatively involved in haemoglobin digestion and eggshell formation including extracellular superoxide dismutase, two histidine-rich proteins, a large blood-brain barrier amino acid transporter and two tyrosinase orthologues. In contrast, transcripts involved in mechanical support (actin), cytoskeletal infrastructure (e.g. dynein light chain 3 and myosin regulatory light chain) and tegumental biology (e.g. TM4SF and Sj25) were more highly represented in adult male schistosomes. Together these data establish a transcriptional basis for adult schistosome labour division and expands the list of novel S. japonicum gender-associated gene transcripts that may be considered targets for improved intervention strategies.

Animals↗
PubMed2006

2-Cys peroxiredoxins from Schistosoma japonicum: the expression profile and localization in the life cycle.

Peroxiredoxin (Prx) is known to be an antioxidant protein that protects the organisms against various oxidative stresses and functions as a signal transductor. Here, we determined the full-length cDNA sequences of three types of Prx from an Asian blood fluke, Schistosoma japonicum: Prx-1, Prx-2 and Prx-3. According to the deduced amino acid sequences, only Prx-3 had a mitochondria-targeting sequence. Using RT-PCR, it was shown that these Prx genes were constitutively expressed in the eggs, cercariae and adult worms of the schistosome. Western blot analysis using antisera specific for each Prx revealed that all the three Prx proteins existed in these developmental stages. By immunolocalization analysis, Prx-1 existed on the surface of a miracidium and in the space between a miracidium and an eggshell. Furthermore, Prx-1 was deposited in the host tissues around the eggs. In adult worms, Prx-1 was not only expressed in the tegument, but also contained in their excretory/secretory products. The surface of the 7 day-schistosomula was stained with anti-Prx-1 antiserum. On the other hand, Prx-2 only existed inside the miracidia in eggs. In addition, Prx-2 was mainly detected in the sub-tegumental tissues, parenchyma, vitelline gland and gut epithelium of the adult worms, but was not detected in the tegument of adults and schistosomula. Taken together with previous reports by other investigators, these data suggest that Prx-1 acts to protect the parasite against the ROS produced by host immune cells, and that Prx-2 plays important roles in intracellular redox signaling and/or in the reduction of ROS generated through the hemoglobinolytic process in the digestive tract.

Amino Acid Sequence↗
PubMed2005

A proton NMR relaxation study of hen egg quality.

A quantitative analysis of NMR proton relaxation in hen egg albumen and yolk is undertaken to research the causes of quality loss during the first few days of storage and to access the feasibility of an on-line NMR sensor of internal egg quality. It is shown that the change in the transverse relaxation in thick egg albumen mainly results from an increase in proton exchange rate resulting from a pH increase attributed to loss of carbon dioxide by diffusion through the eggshell. The results suggest that the low-field T1 is the best relaxation time indicator of albumen quality.

Animals↗
PubMed2004

Aplysia capsulin is localized to egg capsules and egg cordon sheaths and shares sequence homology with Drosophila dec-1 gene products.

Differential library screening of an albumen gland cDNA library, Western blot analysis, protein expression, immunolocalization studies, comparative genomics, and secretion assays identified a major Aplysia californica albumen gland protein ('capsulin') that is localized to egg capsules and to the sheaths of the egg cordon. Capsulin shared sequence homology with eggshell proteins encoded by the Drosophila dec-1 gene. The 1790-amino acid A. californica precursor contains 17 repeat sequences that are flanked by basic residue processing sites. The numerous proteolytic processing sites may facilitate the breakdown of capsulin prior to when veliger larvae break out of egg capsules as free-swimming larvae. An Aplysia brasiliana capsulin repeat sequence was 97% identical to its A. californica homolog. Capsulin fragments were not detected in the eluates of egg cordons, suggesting that capsulin is not a candidate water-borne pheromone precursor.

Amino Acid Sequence↗
PubMed2026

The current and future perspective of ChickenGTEx project and its applications in precision breeding.

The Chicken Genotype-Tissue Expression (ChickenGTEx) project was established to systematically characterize the regulatory landscape of the chicken genome and to accelerate the translation of functional genomics into precision breeding. By integrating whole-genome sequencing with multi-tissue transcriptomic profiling, ChickenGTEx provides a comprehensive atlas of gene expression regulation across diverse tissues and physiological systems. Current findings demonstrate that complex production traits are governed by coordinated regulatory networks rather than isolated loci, with substantial contributions from tissue-specific gene expression, structural variation, and genotype-by-sex interactions. Sex-dependent regulatory effects further refine the genetic architecture of metabolic, immune, and reproductive traits, highlighting the importance of incorporating sex as a biological variable in genomic analyses. Application of integrative omics frameworks within elite layer populations has revealed multilayer regulatory mechanisms underlying extended laying performance, feed efficiency, metabolic health, and eggshell quality. By partitioning phenotypic variance into genetic, regulatory, and host-microbiome components, these approaches move beyond association-based mapping toward causal inference and biological interpretation. Importantly, validated regulatory loci identified through ChickenGTEx and related analyses provide actionable markers for genomic selection and rational targets for precision genome modification. Looking forward, continued expansion of regulatory atlases, incorporation of single-cell and longitudinal data in diverse environmental conditions, and integration of functional annotation into breeding pipelines will further enhance prediction accuracy and sustainable genetic improvement. The ChickenGTEx project thus represents a foundational platform bridging functional genomics and practical poultry breeding.

Animals↗
PubMed2026

Genomic diversity, antimicrobial resistance, and virulence-associated characteristics of Escherichia coli recovered from poultry hatchery-box material.

Hatcheries are early points of exposure of newly hatched chicks to Escherichia coli from eggshell debris, dust, meconium, and the hatchery environment. This study used descriptive genomic surveillance to characterize population structure, antimicrobial resistance, virulence-associated genes, plasmid replicons, and genetic relatedness in a purposively selected collection of E. coli recovered from hatchery-box material in a Czech commercial poultry hatchery. From 83 samples collected between 2019 and 2023, 409 isolates were recovered. Following within-sample reduction based on antimicrobial susceptibility profiles and PCR screening for selected APEC-associated virulence genes, 91 isolates enriched for cefotaxime-medium recovery or APEC-associated gene profiles were selected for Illumina whole-genome sequencing. The sequenced collection comprised 35 sequence types across nine phylogenetic groups or clades; phylogroup B1 (59/91) and ST162 (28/91) predominated. ColV-associated markers were detected in 88 isolates, acquired resistance genes in 61, and a multidrug-resistant phenotype in 31. Seventeen isolates were resistant to ceftazidime; eight carried ESBL or plasmid-mediated AmpC determinants, while eight additional isolates had the chromosomal ampC promoter substitution C-42T as the only identified determinant associated with this phenotype. Closely related isolates, including ST131, ST162, and ST675, were recovered from different samples or parent-farm groups within restricted sampling periods. These findings document genomically diverse, resistance- and virulence-associated E. coli in hatchery-box material and identify genetically related isolates that warrant investigation through structured longitudinal sampling. Because sampling was unequal and isolates were purposively selected, the findings do not provide prevalence estimates or demonstrate source, transmission, persistence, or pathogenicity.

APEC-associated virulence genes↗
PubMed2004

Extracellular enzymes serving as virulence factors in nematophagous fungi involved in infection of the host.

Extracellular enzymes, including serine protease, chitinase and collagenase, corresponding to the main chemical constituents of the nematode cuticle and eggshell, have been reported to be involved in the infectious process as virulence factors. This review will focus on the categories, characterization, purification, cloning and potential function of these virulence enzymes and will attempt to provide new insights into the mechanisms of fungal pathogenesis in nematodes.

Amino Acid Sequence↗
PubMed2006

Ventilatory roll off during sustained hypercapnia is gender specific in pekin ducks.

The objective of the present study was to examine the relative roles of peripheral versus central mechanisms in producing ventilatory adjustments in pekin ducks during prolonged (5 h) hypercapnia (5% inspired CO2), and to determine whether these adjustments differed between male and female ducks. After 20 min of CO2 exposure, intact ducks increased total ventilation (VE) 2.5-3-fold above control values, due to large increases (approximately 200%) in tidal volume (VT) and slightly smaller increases (approximately 140%) in breathing frequency (fR). This response was accompanied by respiratory acidosis (pHa fell from approximately 7.46 to approximately 7.41) and hypercapnia (PaCO2 increased from approximately 35 to approximately 40 Torr). In males, VE fell progressively thereafter due exclusively to a fall in fR, in parallel with a rapid partial recovery of pH (to 7.44) while PaCO2 continued to climb (to approximately 42 Torr). In females, VE remained elevated during hypercapnia, and no pH recovery occurred. This suggests that a respiratory decline resulting from acid-base compensation (probably due to HCO3- mobilization) occurred in males but not in females. Bicarbonate mobilization, and thus pH compensation, may have been reduced in females due to the CaCO3 requirements of eggshell formation. In males, the acute ventilatory response was reduced slightly by denervation of the carotid bodies or intrapulmonary chemoreceptors, but there was no effect of denervation of either receptor group on the responses to prolonged CO2. We conclude that pH compensation triggered by constant or increasing PaCO2, acting at central chemoreceptors, likely mediates the respiratory adjustments seen in male pekin ducks during hypercapnia. Furthermore, we suggest that this ventilatory response be considered a gender-specific hypercapnic ventilatory roll off, in the context of the various time domains of the hypercapnic ventilatory response.

Adaptation, Physiological↗
PubMed2006

Reproductive effects of heavy metal accumulation on breeding feral pigeons (Columba livia).

To investigate the effects of heavy metal accumulations on breeding birds, we compared the egg size, eggshell thickness and some reproductive parameters in feral pigeon populations collected from Seoul and Ansan colonies. The results showed that concentrations of Pb in bone and Cd in kidney of adult pigeons in Seoul were three times higher than in Ansan colony. Significant positive correlation was also observed between Pb and Zn in bone and Cd and Zn in kidney of adult pigeons from Seoul, but not Ansan. This indicates that pigeons at Seoul may be affected more by the toxic Pb and Cd exposure in the environment rather than those at Ansan because of the antagonistic action of Zn against Pb and Cd toxicity. No significant difference was observed in egg characteristics (egg length, width and shell thickness), clutch size (number of eggs per clutch), incubation periods and hatchability of squabs between the two study sites. Although no significant difference was observed, body weight, and primary wing, bill and tarsus lengths of nestlings from Seoul which is more polluted were rather smaller than those from Ansan. Nestlings at Seoul fledged significantly later than at the less polluted site (Ansan). We also observed significantly lower fledging success at Seoul than Ansan colony. Elevated metal exposure may thus result in decreasing growth rate in pigeon nestlings resulting in fledging length and fledging success. Our results suggest a possible effect of heavy metal bioaccumulation on breeding of feral pigeons.

Animals↗
PubMed2004

bullwinkle is required for epithelial morphogenesis during Drosophila oogenesis.

Many organs, such as the liver, neural tube, and lung, form by the precise remodeling of flat epithelial sheets into tubes. Here we investigate epithelial tubulogenesis in Drosophila melanogaster by examining the development of the dorsal respiratory appendages of the eggshell. We employ a culture system that permits confocal analysis of stage 10-14 egg chambers. Time-lapse imaging of GFP-Moesin-expressing egg chambers reveals three phases of morphogenesis: tube formation, anterior extension, and paddle maturation. The dorsal-appendage-forming cells, previously thought to represent a single cell fate, consist of two subpopulations, those forming the tube roof and those forming the tube floor. These two cell types exhibit distinct morphological and molecular features. Roof-forming cells constrict apically and express high levels of Broad protein. Floor cells lack Broad, express the rhomboid-lacZ marker, and form the floor by directed cell elongation. We examine the morphogenetic phenotype of the bullwinkle (bwk) mutant and identify defects in both roof and floor formation. Dorsal appendage formation is an excellent system in which cell biological, molecular, and genetic tools facilitate the study of epithelial morphogenesis.

Animals↗
PubMed2006

Graded maternal short gastrulation protein contributes to embryonic dorsal-ventral patterning by delayed induction.

Establishment of the dorsal-ventral (DV) axis of the Drosophila embryo depends on ventral activation of the maternal Toll pathway, which creates a gradient of the NFkB/c-rel-related transcription factor dorsal. Signaling through the maternal BMP pathway also alters the dorsal gradient, probably by regulating degradation of the IkB homologue Cactus. The BMP4 homologue decapentaplegic (dpp) and the BMP antagonist short gastrulation (sog) are expressed by follicle cells during mid-oogenesis, but it is unknown how they affect embryonic patterning following fertilization. Here, we provide evidence that maternal Sog and Dpp proteins are secreted into the perivitelline space where they remain until early embryogenesis to modulate Cactus degradation, enabling their dual function in patterning the eggshell and embryo. We find that metalloproteases encoded by tolloid (tld) and tolkin (tok), which cleave Sog, are expressed by follicle cells and are required to generate DV asymmetry in the Dpp signal. Expression of tld and tok is ventrally restricted by the TGF-alpha ligand encoded by gurken, suggesting that signaling via the EGF receptor pathway may regulate embryonic patterning through two independent mechanisms: by restricting the expression of pipe and thereby activation of Toll signaling and by spatially regulating BMP activity.

Animals↗
PubMed2005

Reassessment of ecotoxicities of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane in Japanese quail under the OECD draft new avian one-generation reproduction test guideline.

Ecotoxicological hazards of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT) were investigated by a one-generation reproduction study using Japanese quail (Coturnix coturnix japonica) under an Organization for Economic Co-operation and Development (OECD) draft new test guideline 206 following acute and subchronic toxicity studies. In the subchronic feeding toxicity study, tremors, convulsions, and deaths were observed with a clear sex difference, males being more susceptible than females. The estimated total number of sperm tended to decrease in a dose-dependent manner at the end of 6-week treatment. In the one-generation reproduction study conducted at dose levels of 0, 6, 30, and 150 ppm, the estimated total number of sperm tended to decrease in a dose-dependent manner with a significant difference at 150 ppm. Tremors were observed in the majority of hatchlings in the 150 ppm group and at lower incidences in the 30 ppm group. Significantly high mortality rate in chicks persisted from treatment week 3-6 in the 150 ppm group and at treatment weeks 4 and 5 in the 30 ppm group. Despite of these severe adverse effects of p,p'-DDT on hatchlings and chicks, fertilization, egg laying, eggshell thickness or embryonic development was hardly impaired by p,p'-DDT or its metabolites. From these results, it appears that the OECD draft new avian one-generation reproduction test guideline is effective for ecological hazard assessment of chemicals.

Administration, Oral↗
PubMed2004

Extraembryonic membrane development in a reproductively bimodal lizard, Lacerta (Zootoca) vivipara.

Reproductive mode has been remarkably labile among squamate reptiles and the evolutionary transition from oviparity to viviparity commonly has been accompanied by a shift in the pattern of embryonic nutrition. Structural specializations for placental transfer of nutrients during intrauterine gestation are highly diverse and many features of the extraembryonic membranes of viviparous species differ markedly from those of oviparous species. However, because of a high degree of evolutionary divergence between the species used for comparisons it is likely that the observed differences arose secondarily to the evolution of viviparity. We studied development of the extraembryonic membranes and placentation in the reproductively bimodal lizard Lacerta vivipara because the influence of reproductive mode on the structural/functional relationship between mothers and embryos can best be understood by studying the most recent evolutionary events. Lecithotrophic viviparity has evolved recently within this species and, although populations with different reproductive modes are allopatric, oviparous and viviparous forms interbreed in the laboratory and share many life history characteristics. In contrast to prior comparisons between oviparous and viviparous species, we found no differences in ontogeny or structure of the extraembryonic membranes between populations with different reproductive modes within L. vivipara. However, we did confirm conclusions from previous studies that the tertiary envelope of the egg, the eggshell, is much reduced in the viviparous population. These conclusions support a widely accepted model for the evolution of squamate placentation. We also found support for work published nearly 80 years ago that the pattern of development of the yolk sac of L. vivipara is unusual and that a function of a unique structure of squamate development, the yolk cleft, is hematopoiesis. The structure of the yolk sac splanchnopleure of L. vivipara is inconsistent with a commonly accepted model for amniote yolk sac function and we suggest that a long standing hypothesis that cells from the yolk cleft participate in yolk digestion requires further study.

Journal Article↗
PubMed1996

The pattern and distribution of calcified mediastinal lymph nodes in sarcoidosis and tuberculosis: a CT study.

UNLABELLED: Following granulomatous involvement, calcification of hilar and mediastinal lymph nodes is common and calcified nodes are frequently identified on computed tomography (CT). The aim of this study was to establish whether there is any difference in the pattern and distribution of such calcifications in tuberculosis (TB) and sarcoidosis. METHODS: The thoracic CT scans of 77 patients with proven TB (n=28) or sarcoidosis (n=49) were studied retrospectively. Lymph nodes were categorized by size and pattern of calcification: diffuse/homogeneous, focal deposits, eggshell, and complete nodal replacement by calcification. The position of hilar or mediastinal calcified nodes was recorded. RESULTS: Nodal calcification was present in 26 fo 49 (53%) sarcoidosis patients and 13 of 28 (46%) TB patients. The mean short axis diameter of calcified nodes was significantly larger in sarcoidosis patients (sarcoidosis 12 mm, TB 7 mm, P < 0.003). A focal pattern of calcification was commoner in sarcoidosis (58% sarcoidosis nodes, 23% TB nodes) and complete calcification in TB (62% TB nodes, 27% sarcoidosis nodes). When hilar node calcification was present it was more likely to be bilateral in sarcoidosis than in TB (65% and 8%, respectively, P < 0.001). CONCLUSION: CT of the mediastinum shows significant differences in distribution and pattern of calcification in lymph nodes in TB and sarcoidosis. Possible explanations for these differences include the route of lymphatic drainage of pulmonary TB and the caseating nature of tuberculous granulomas.

Adult↗
PubMed1978

The chick embryo choriallantoic membrane as a bioassay for angiogenesis factors: reactions induced by carrier materials.

A variety of filter materials, sponges, and gels were placed on the chick chorioallantoic membrane (CAM), the reactions of it investigated and compared with those induced by natural egg materials (white eggshell membrane, coagulated albumen and yolk). Independently of the kind and nature of the naterials the CAM reacted nearly regularly underneath these diverse materials with a proliferation of ectodermal cells, fibroblasts, and blood vessels forming a highly capillarized granulation tissue. The area of the CAM surrounding the foreign materials frequently displayed an increase of small blood vessels macroscopically discernible and showing a radial arrangement (spoke-wheel-appearance according to FOLKMAN 1974). It is concluded that this type of vascular reaction cannot be considered as a characteristic feature for the action of a special tumour angiogenesis factor, since it can be induced by a variety of stimuli leading to an inflammatory reaction in the CAM. For the detection of special angiogenetic activities an objective quantification of the vessel reactions is necessary under consideration of the reactions induced by the mere presence of such foreign materials.

Allantois↗
PubMed2000

Amyloids protect the silkmoth oocyte and embryo.

Chorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of proteins that have remarkable mechanical and chemical properties protecting the oocyte and the developing embryo from a wide range of environmental hazards. We present data from electron microscopy (negative staining and shadowing), X-ray diffraction and modeling studies of synthetic peptide analogues of silkmoth chorion proteins indicating that chorion is a natural amyloid. The folding and self-assembly models of chorion peptides strongly support the beta-sheet helix model of amyloid fibrils proposed recently by Blake and Serpell [Structure 4 (1996) 989-998].

Amino Acid Sequence↗