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At least 937 records · Page 52Linked to original sources
PubMed1979

Antigenic activity in adult Dipetalonema viteae in the indirect immunofluorescent test against sera from filariasis patients--the immunofluorescent histological search for "pure" antigen.

Using IFAT, it has been shown that isolated egg-shells and uterine fluid of Dipetalonema viteae are the most potent antigens in heterologous systems using human sera from patients infected with Wuchereria bancrofti, Onchocerca volvulus and Loa loa, as well as in homologous systems using sera from animals infected with D. viteae. It is suggested that these antigens are unlikely to be highly species-specific, and that anatomical isolation of antigens is a necessary prerequisite to immunochemical analysis aimed at the preparation of a "pure" antigen.

Animals↗
PubMed1985

Establishment of dorsal-ventral polarity in the Drosophila embryo: the induction of polarity by the Toll gene product.

Drosophila females that lack Toll gene activity produce dorsalized embryos, in which all embryonic cells behave like the dorsal cells of the wild-type embryo. Injection of wild-type cytoplasm into young Toll- embryos restores their ability to produce a normal dorsal-ventral pattern in a position-dependent manner. No matter where the cytoplasm is injected relative to the dorsal-ventral axis of the egg shell, the position of the injected cytoplasm defines the ventralmost part of the rescued pattern. Although injection of wild-type cytoplasm into mutants at six other dorsal-group loci also restores the ability to produce lateral and ventral structures, only Toll- embryos lack any residual dorsal-ventral polarity. Experiments suggest that the activity of the Toll product is normally regulated by other dorsal-group genes and that the function of the Toll product is to provide the source for a morphogen gradient in the dorsal-ventral axis of the wild-type embryo.

Animals↗
PubMed1992

slow border cells, a locus required for a developmentally regulated cell migration during oogenesis, encodes Drosophila C/EBP.

During Drosophila oogenesis six to ten follicle cells, the border cells, undergo a dramatic and stereotypic migration through the developing egg chamber. We identified four independent P element insertion mutations that specifically blocked border cell migration. They defined a single, novel locus that was named slow border cells (slbo), because hypomorphic alleles caused delayed onset of the migration. Laser ablation of the border cells, or failure of their migration, caused improper morphogenesis of the micropyle, the egg-shell structure through which the sperm enters at fertilization. The slbo locus was found to encode a product homologous to the CCAAT/enhancer-binding protein (C/EBP), a basic region-leucine zipper transcription factor. Drosophila C/EBP may be required for the expression of gene products mediating border cell migration.

Amino Acid Sequence↗
PubMedDate not supplied

Effects of AFB1 embryonic exposure on chicken mononuclear phagocytic cell functions.

Effects of embryonic exposure to aflatoxin-B1 (AFB1) on the postnatal development of chicken mononuclear phagocytic system function was examined. Single exposure of 6-d chick embryos to 0.1, 0.5, and 1 micrograms AFB1 in 10 microL acetone was employed. Control embryos received 10 microliters solvent and sham-treated controls included embryos with a hole in the egg shell with no compound added. Aflatoxin B1 exposure caused a dose-related increase in embryonic mortality. After hatch, no differences were observed in body weight gain among treatment groups. The incidence of circulating thrombocytes was reduced in chicks exposed to the highest AFB1 dose with enhancement in monocyte and lymphocyte cell populations. Birds exposed to 1 microgram AFB1 recruited fewer macrophages in the peritoneal cavity after i.p. Sephadex elicitation along with reduced substrate adherence potential of peritoneal exudate cells. Similarly, macrophages from 0.5 and 1 micrograms AFB1-treated birds had depressed phagocytic potential. These results suggest that long-term immune depression of macrophage-mediated functions can occur following embryonic exposure to AFB1.

Aflatoxin B1↗
PubMed1996

Exposure to different wavelengths of light and the development of structural and functional asymmetries in the chicken.

The thalamofugal visual projections of the chick are known to develop in response to stimulation by light prior to hatching, and asymmetry in the number of projections develops as a consequence of the embryo being oriented in the egg so that it occuludes its left eye. The right eye only is stimulated by light and this causes the visual projections connected to the right eye to develop in advance of those connected to the left. We have now found that exposure of embryos, from day 19 of incubation to hatching, to red (peak transmission at 670 nm) or green (peak at 500 nm) light is as effective as broad-spectrum (white) light in establishing asymmetry in these projections. The intensities of the light to which the embryos were exposed in each case were equivalent, achieved in part by removing the air sac end of the egg shell. The thalamofugal visual projections, therefore, develop in response to light stimulation but appear to have no wavelength specificity. This result is consistent with the apparent lack of involvement of the thalamofugal visual pathway in colour vision. However, functional asymmetry, tested as left-right eye differences in categorising grain from pebbles, was found to be less marked in the chicks that had been exposed to green light compared to those that had been exposed to 'while' light, and it was absent in those exposed to red light or incubated in the dark. Thus, there is wavelength specificity for the development of the behavioural asymmetry, which suggests involvement of colour-coded neurons outside the thalamofugal visual pathway, probably in the tectofugal pathway. Exposure of the embryos to red and green light alternating at 30 min intervals is as effective as "white' light for establishing both the structural and functional asymmetry.

Animals↗
PubMed1991

Characterization of an Onchocerca volvulus cDNA clone encoding a genus specific antigen present in infective larvae and adult worms.

The isolation and characterization of a recombinant cDNA clone (OV7) expressing an antigen present in Onchocerca volvulus infective larvae and adult stages is described. Using chimpanzee antiserum generated against irradiated infective larvae, we isolated a cDNA clone from a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA. The open reading frame encodes 131 amino acids corresponding to a 15.2-kDa protein. Affinity purified antibodies which bound specifically to OV7 fusion polypeptide recognized a single antigen with an apparent molecular weight of 17,000 in extracts of L3, L4 and adult worms. Immunoelectron microscopy established that the antigen encoded by this clone is present in the hypodermis and the basal layer of the cuticle of L3 and female adult worm, and in the egg shell around developing microfilariae. Since the OV7 fusion polypeptide is onchocerca-specific and is recognized specifically by sera from onchocerciasis patients, and sera from non-patent but infected chimpanzees, and not by sera from patients with other filarial parasites, it may have potential as an antigenic component in a test for detection of non-patent and patent infections of O. volvulus. The OV7 amino acid sequence contains residues that have a probable homology with the cysteine proteinase inhibitor superfamily.

Amino Acid Sequence↗
PubMed1991

Psychrotrophy and foodborne Salmonella.

Recent reports on the behaviour of Salmonella at chill temperatures (less than 10 degrees C) raise concerns on the purported safety of refrigerated foods. The propensity for growth of salmonellae within 10-28 days in complex broth (5.9 degrees C) and agar (4.0 degrees C) media is overshadowed by more recent evidence on their capability to proliferate in fresh meats (2.0 degrees C) and shell eggs (4.0 degrees C) within 6 and 10 days, respectively. Such findings, together with the inability of many domestic refrigerators to maintain uniformly cold temperatures, are disquieting. Gaseous mixtures of CO2, N2 and O2 are widely used to extend the shelf life of chilled foods, notably fresh meats. The high levels of CO2 used in modified atmosphere packaging or generated by endogenous microflora in vacuum-packaged foods effectively inhibit the growth of psychrotrophic spoilage bacteria. Current evidence suggests that this industrial practice also arrests the growth of Salmonella but exerts little or no effect on their survival. Enhancement of the bacteriostatic potentials of pH and NaCl as temperature deviates from the optimum for growth to lower values could further contribute to the safety of chilled foods.

Cold Temperature↗
PubMed1996

Prevalence of thermophilic Campylobacter and Arcobacter butzleri in food of animal origin.

Thermophilic campylobacters and Arcobacter butzleri were looked for in 57 manually shelled egg samples and 130 raw meat samples. No bacteria were found in the egg samples, but they were, however, found in 16.1% of meat samples with a frequency varying from 2.4% (port sausage) to 37.5% (poultry). A total of 21 strains were identified, one belonging to Arcobacter butzleri (pork) and 20 to Campylobacter. The most common species was C. jejuni (16/20) followed by C. coli (4/20) and in both species biotype I was the most frequently found. Regarding the methods employed for the isolation of bacteria, no substancial difference was seen between the three media (Butzler, CCDA and Preston) although CCDA medium gave better results than Butzler and Preston media. The variable which had the most influence was the incubation temperature. A higher number of strains was obtained at 42 degrees C than at 37 degrees C.

Bacteria↗
PubMed1983

Experimental analysis on the variations of acid-base balance in the chick embryo.

1. The pH remains steady, 7.57. 2. The pCO2 increases gradually. We believe this is fundamental for hatching. 3. Bicarbonate and base excess increase from acidosis to alkalosis due to absorption of the egg shell. 4. The pO2 increases in stage 41 and 42 due to pulmonary respiration. 5. The pO2 drop prior to hatching due to involution of the chorioalantoid membrane and increasing requirements.

Acid-Base Equilibrium↗
PubMed1987

Ecdysteroids during embryonation of eggs of Ascaris suum.

1. The optimal temperature for in vitro development of fertilized eggs of Ascaris suum was 24 degrees C. 2. Samples (2 X 10(7) eggs) were obtained from in vitro embryonating cultures every 3 days for 4 weeks; lipids were extracted, partially purified, fractionated with HPLC and analyzed for ecdysteroids by radioimmunoassay. 3. Free ecdysone and 20-hydroxyecdysone (20-HE) were at low levels (less than 20 pg) in freshly excised eggs and rose to maximal values on day 6 of embryonation. 4. Conjugated ecdysone and conjugated 20-HE rose to maximal values on day 9. 5. Both free and conjugated ecdysteroids were undetectable from days 15 to 27 of cultivation. 6. These profiles indicate that ecdysteroids might have a selective role in nematode embryonation and/or tanning of the egg shell.

Animals↗
PubMed1982

Isolation and purification of Fasciola hepatica eggs.

The present egg isolation method is both a rapid and simple technique for recovering large numbers of Fasciola hepatica eggs (1 X 10(7) eggs/gradient) from bovine bile. Bile from infected cattle was first passed through a 45 micron screen sieve. The F. hepatica eggs were collected from the surface of the screen by backwashing with a jet of distilled water. The resultant egg suspension was layered on a 60% to 100% (v/v) linear Percoll gradient prepared in distilled water. Centrifugation at 450 g for 20 min resulted in the formation of 2 visible bands and a pellet. The top band (density of 1.075 g ml-1) contained viscous debris and crystallized bile pigments. The second visible band (density of 1.093-1.099 g ml-1) consisted of a relatively pure population of F. hepatica eggs (greater than 93%) while the pellet contained only F. hepatica egg shells.

Animals↗
PubMed1994

Changes in metabolic activity in the hyperstriatum of the chick before and after hatching.

Changes in metabolic activity in the hyperstriatal regions of the chick forebrain have been assessed just prior to and after hatching using [14C] 2-deoxyglucose (2-DG) autoradiography. Embryos were injected on day E19, followed by either exposure to light for 30 min or being held in darkness. Other embryos were injected on day E20, after pipping of the egg shell had occurred, and chicks were injected on day 1 (D1) after hatching, followed by light exposure. In the E19 groups metabolic activity in visual regions of the hyperstriatum accessorium (HA) was significantly higher than that in the hyperstriatum dorsale (HD), the region which receives the thalamofugal visual projections. The result was the same in both the light and dark exposed embryos, indicating that the high level of activity in HA on day E19 is not visually driven and that HA may be processing inputs from other sensory modalities. At stage E20 the activities of HA and HD did not differ and by day 1 post-hatching HD activity exceeded that of HA. Activity in HA fell between E19 and E20, while in HD activity rose between E20 and D1. The developmental sequence of metabolic activity levels in the intermediate medial hyperstriatum ventrale (IMHV), a region involved with imprinting memory formation, was higher on E19 and D1 than on E20. E20 is thus a quiescent period of neural activity in the hyperstriatum prior to hatching. Although a small number of the embryos showed distinct hemispheric asymmetries in metabolic activity, overall there was no significant asymmetry in the embryo groups. The implications of these results for imprinting and early perceptual processing are discussed: it appears that HA activity may be inhibited or limited during the sensitive period for visual imprinting, thereby temporarily diminishing the importance of the thalamofugal visual pathway relative to the tectofugal pathway in the imprinting process.

Animals↗
PubMed2006

Relationship of cloacal gland with testes, testosterone and fertility in different lines of male Japanese quail.

An attempt has been made to investigate the relationship of cloacal gland with testes, testosterone and fertility in different lines of Japanese quail (Coturnix coturnix japonica). For this study, three lines of healthy adult male Japanese quails (<12 weeks) viz., heavy body weight (HB), white breasted (WB), and white egg shell (WES) were taken. They were housed in individual cages under uniform husbandry conditions and were provided with normal quail breeder ration and water ad libitum, with 14 h light/day. The experimental birds were selected from each of these three lines and categorized into different groups (15 birds/group) based on the increasing order of the area of cloacal gland. At the end of this experiment (24 weeks) the data indicated that size of the cloacal gland was directly proportional to foam discharge, foam weight, testicular weight, fertility and testosterone concentration in plasma. From this study it may be concluded that area of cloacal gland in Japanese quail is positively correlated with testicular weight, level of testosterone in plasma and fertility. Visual examination of cloacal gland and cloacal foam may provide a valuable non-invasive tool for predicting the fertilizing ability of individual male bird.

Animals↗
PubMed2004

Corticosterone treatment of the chick embryo affects light-stimulated development of the thalamofugal visual pathway.

By injecting a single 60 microg dose of corticosterone into the eggs of domestic chicks on day 18 of incubation, we have shown that elevated levels of this hormone affect the development of asymmetry in the visual projections from the thalamus to the Wulst regions in the left and right hemispheres of the forebrain. In vehicle-treated (control) embryos this visual pathway develops asymmetry in response to light stimulation during the final stages of incubation, when the embryo is oriented so that its left eye is occluded by its body and its right eye can be stimulated by light entering through the egg shell. Pre-hatching exposure to light leads to more projections from the left side of the thalamus to the right Wulst than from the right side of the thalamus to the left Wulst, as confirmed here by injection of the tracers Fluorogold and Rhodamine into the left and right Wulst followed by counting the number of labelled cell bodies in the thalamus (asymmetry greater in males than females). The chicks injected with corticosterone pre-hatching did not develop any group bias for asymmetry in response to light exposure before hatching. They were random with respect to presence/absence of lateralization and, when present, the lateralization was not as strong as in the controls and its direction was random. The corticosterone-treated group had fewer projections from the left side of the thalamus to the right Wulst than did the controls. The results are considered with respect to maternal deposits of the hormone in the yolk and pre-hatching stress of the embryo.

Animals↗
PubMed2005

Comparative study of mycelial growth and basidiomata formation in seven different species of the edible mushroom genus Hericium.

The potential of using several agricultural by-products as supplements of sawdust substrate for the production of edible mushroom Hericium was evaluated using seven Hericium species. All the tested supplements (rice bran, wheat bran, barley bran, Chinese cabbage, egg shell, and soybean powder) were found to be suitable for the mycelial growth of all the tested species. In mycelial growth, soybean powder was the best supplement for Hericium americanum, Hericium coralloides, and Hericium erinaceum while barley bran was the best for Hericium alpestre, Hericium laciniatum, and Hericium erinaceus. For Hericium abietis, rice bran and Chinese cabbage was the best. The possibility of mushroom production on oak sawdust substrate with 20% rice bran supplement was demonstrated with H. coralloides, H. americanum, H. erinaceus, and H. erinaceum which showed 26-70% biological efficiency. Our results also showed that strain selection is important to improve biological efficiency and mushroom yield in Hericium cultivation.

Agriculture↗
PubMed2006

Egg components, egg size, and hatchling size in leatherback turtles.

Relationships between egg size, egg components, and neonate size have been investigated across a wide range of oviparous taxa. Differences in egg traits among taxa reflect not only phylogenetic differences, but also interactions between biotic (i.e., maternal resource allocation) and abiotic (i.e. nest environment conditions) factors. We examined relationships between egg mass, egg composition, and hatchling size in leatherback turtles (Dermochelys coriacea) because of the unique egg and reproductive characteristics of this species and of sea turtles in general. Albumen comprised 63.0%+/-2.8% (mean+/-S.D.) of egg mass and explained most of the variation in egg mass, whereas yolk comprised only 33.0%+/-2.7%. Additionally, leatherback albumen dry mass was approximately 16% of albumen wet mass. Whereas hatchling mass increased significantly with egg mass (n = 218 clutches), hatchling mass increased by only approximately 2 g for each 10 g increase in egg mass and was approximately 10-20 g greater than yolk mass. Taken together, our results indicate that albumen might play a particularly significant role in leatherback embryonic development, and that leatherback eggs are both capable of water uptake from the nest substrate and also possess a large reservoir of water in the albumen. Relationships between egg mass and egg components, such as variation in egg mass being largely explained by variation in albumen mass and egg mass containing a relatively high proportion of albumen solids, are more similar to bird eggs than to eggs of other non-avian reptiles. However, hatchling mass correlates more with yolk mass than with albumen mass, unlike patterns observed in bird eggs of similar composition.

Animals↗