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At least 19 recordsLinked to original sources
PubMed2026

Shared candidate genes associated with variation in egg size in cold-adapted and artificially selected Drosophila melanogaster.

The development of most multicellular organisms begins with oogenesis, the production of the egg. In D. melanogaster, egg size is a highly polygenic trait closely related to fitness. Elements of shifts in egg size have been widely studied and modeled, but the genes underlying this variation are still poorly understood. This study aimed to identify candidate genes associated with processes underlying egg-size variation using D. melanogaster as a model. In selection experiments, we generated large-egg populations from a shared ancestral population using both cold-adaptation and artificial selection, and identified candidate genes for the large-egg phenotype. Using whole-genome DNA sequencing and strict computational filtering, we uncovered single-nucleotide polymorphisms in 10 genes. Characterization of these candidates revealed functions in cytoskeletal dynamics, DNA replication and repair, intracellular signaling, and stem cell maintenance and differentiation. RT-PCR and qPCR were used to validate gene expression differences between cold-adapted lines and the Oregon R control (OrR) in a subset of the candidates. In RT-PCR, stathmin demonstrated a modified expression pattern in all cold-adapted lines relative to OrR controls. In qPCR experiments, Pde1c had significantly higher expression (p&#x202f;<&#x202f;0.05) in the cold-adapted flies compared to OrR controls for all three fly cages tested. For Ino80, significantly higher expression was observed for one of three cages while one cage showed lower expression. We have assembled a candidate list we hope will be a useful resource for researchers across specialties, from germ cells to cytoskeletal dynamics, to further investigate the genetic and developmental aspects of variation in egg size in D. melanogaster.

Animals↗
PubMed1978

Egg size and form as taxonomic criteria in Diphyllobothrium (Cestoda, Pseudophyllidea).

The size and form (length, width, and length: width ratio) of eggs of Diphyllobothrium dendriticum, D. ditremum and D. latum vary considerably among individual worms within each species. The size of eggs varies with host species and a decrease in egg size with increasing intensity of infestation is indicated. The egg size of D. latum increases during the first 10-12 days of egg production. For single worm infections in golden hamsters the mean egg length and width of D. ditremum are significantly smaller than the corresponding means of D. dendriticum and D. latum, while D. latum has significantly wider eggs than D. dendriticum. As taxonomic characteristics, egg size and form may contribute to species delimitation at the population level. For identification at the individual level the best possible accuracy is about 80%. This accuracy is considerably reduced when variation in host species and intensities of infestations are introduced. Scanning electron microscope studies did not reveal any differences among eggs of the three species.

Animals↗
PubMed1975

Molecular sizes of egg yolk very low density lipoproteins fractionated by ultracentrifugation.

Egg yolk very low density lipoproteins isolated from normal eggs were separated into six fractions by preparative ultracentrifugation. The sizes of the molecules in three of the fractions were estimated by gel chromatography and by electron microscopy of the lipoproteins using a negative staining technique. The three fractions had average diameters of 39 nm., 32 n., and 25 nm. and average molecular weights of 17 X 10(6), 10 X 10(6), and 5 X 10(6). There was considerable overlap of size of molecules in the three fractions. Size differences were not observed in the ultracentrifuge separated fractions of very low density lipoproteins isolated from eggs laid by hens receiving crude cottonseed oil in their diets. However, the fatty acids from these fractions differed in stearic and oleic acid contents while those from the normal egg lipoproteins did not. The floating very low density lipoproteins contained more oleic acid and less stearic acid then the sedimenting ones did.

Animals↗
PubMed1975

[Nutritional needs of adult Drosophila: influence of lecithins and of choline chloride on the fecundity, the fertility and the size of ova].

The lecithin or choline chloride deficiency, in Drosophila, results in an important decrease of the number of eggs produced, hatching and egg size. However, the ovogenesis is not completely stopped, even after 15 days. This effects seem caused by the choline deficiency. When used under the chloride form, choline has no toxic effect even at a rate as high as 3 g/litre. However, the lecithin has toxic effects for amounts up to 4 g/litre. In the adults, the optimal concentration could be about 2 g/litre for the lecithin and 300 mg/litre for the cholin chloride.

Animals↗
PubMed1979

The response of three strains of fowl to alpha-chloralose.

A heavy and two light strains of pullets suffered a decline in egg production but an improvement in body weight gains when alpha-chloralose, a tranquilizer, was included in their diets at .1 to .3%. Feed efficiency also experienced a decline while egg size and Haugh unit were not affected.

Animals↗
PubMed1978

Human Ancylostoma infections in Nigeria.

An estimate of the proportion of infections with Ancylostoma duodenale and Necator americanus by the examination of larvae collected from the stools of 220 persons infected with hookworm was made. Fifty-nine per cent of the infections were due to N. americanus only: A. duodenale always occurred in association with N. americanus. In 12% of the infections it is suggested that there were approximately three female A. duodenale to 95 female N. americanus. The highest numbers of A. duodenale in mixed infections (28 female A. duodenale with 45 female N. americanus) occurred in only 1% of the infections. Evidence is given that egg size can be important in the differentiation of the two species. A method of calculating the proportion of the two hookworms, and hence of other intestinal nematodes, in mixed infections in an individual as well as in the general population, is also described.

Adolescent↗
PubMed1979

The rapid transmembrane movement of cholesterol in small unilamellar vesicles.

The exchange of cholesterol between two populations of small unilamellar vesicles has been investigated using a new system. Uniformly sized egg lecithin-cholesterol vesicles containing [3H]cholesterol and the glycolipid N-palmitoyl-DL-dihydrolactocerebroside were used as donors, whereas similar vesicles containing unlabelled cholesterol and no glycolipid were used as cholesterol acceptors. The two populations of vesicles were separated with the castor bean lectin Ricinus communis. It was found that greater than 90% of the cholesterol in the donor vesicle could be exchanged with a single time constant, the half-time for the completion of this exchange process being 1.5 h at 37 degrees C. Therefore, the rate of transmembrane movement or flip-flop of cholesterol in these vesicles must be at least as fast as the intermembrane exchange process. Similar results were obtained using hemoglobin-free human erythrocyte ghosts as the acceptor membrane. If the molecular-sieve chromatography step used to fractionate the vesicles was omitted, a non-exchangeable pool of cholesterol was detected which was shown not to be due to the presence of multilamellar vesicles.

Biological Transport↗
PubMed1979

Geographic and host-related variation among species of Fessisentis (Acanthocephala) and confirmation of the Fessisentis fessus life cycle.

Specimens of the 4 known species of Fessisentis, acquired through new collections in 6 states and laboratory infections, were compared with existing descriptions and collections. It was concluded that the number od longitudinal rows of proboscis hooks and lengths of proboscis receptacles, largest proboscis hooks, and reproductive systems are not useful in distinguishing the species. Egg size is of limited usefulness. Regardless of host or geographical locality, proboscis shape and length, the number of proboscis hooks in each longitudinal row, hook shape and size distribution, number of testes, number of cement glands, and female genital pore position are consistent differences. Cystacanths of Fessisentis fessus occurred in aquatic isopods, Asellus forbesi and Lirceus lineatus, in Jackson County, Illinois, where Siren intermedia is the usual definitive host. Laboratory infections confirmed the life cycle of this species.

Acanthocephala↗
PubMedDate not supplied

A focus of human fascioliasis in the Nile Delta, Egypt.

This study was carried out in Abis II village. A representative sample of the population was examined for parasitic infections. Of these 40 cases were positive for Fasciola ova and the diagnosis was confirmed. The prevalence of fascioliasis was 7.3 per cent. The egg size was determined in both human and animal samples. Although the ova measurements corresponded in many instances to Fasciola hepatica, yet the identification of the Fasciola spp. needs further investigations.

Adolescent↗
PubMedDate not supplied

[Cystogenous nematode, Heterodera (Globodera) mali sp. n., an apple parasite in Kazakhstan].

There has been no information on cystogenous nematodes of the genus Heterodera injuring apple trees. The paper checks the first finding of these nematodes on the roots of a cultivated apple tree. The nematodes proved to be a new species, Heterodera mali sp. n. The apple cystogenous nematode resembles the potato cystogenous nematode H. rostochiensis Woll. in having a round body, small cleft of the vulva and similar sizes of eggs. It differs from H. rostochiensis in smaller sizes (on the average 5 against 9) very transparent and thin cuticle, a small distance between vulva and anus (on the average 43 against 86), a smaller value of the Granek's index (on the average 1.3 against 4.6), a smaller number of cuticular folds between vulva and anus (on the average 7 against 21) and different plant-hosts. A detailed description of H. mali sp. n. is given.

Animals↗
PubMed1978

Immunization of pigs against experimental Ascaris suum infection by feeding ultraviolet-attenuated eggs.

Pigs fed Ascaris suum eggs attenuated by short-wave ultraviolet radiation developed a resistance to challenge infections that varied according to the protocols used. Two doses of eggs irradiated at total exposures (ET) of 150 muW-min/cm2 resulted in a reduction of adult worm burden in 3 groups challenged with 50, 100, or 500 eggs by 45, 35, and 49%, respectively. However, these results were not statistically significant (P greater than 0.05). Three other groups were fed eggs as follows: Group 1, 3 doses irridated at ET's of 150, 150 and 150; Group 2, 3 doses irradiated at ET's of 150, 150, 100; and Group 3, 3 doses irradiated at ET's of 150, 100, and 75. All of these regimens provided significant protection: Group 1 (P less than 0.02), Group 2 (P less than 0.05), Group 3 (P less than 0.001). An analysis of the lengths of worms recovered showed that in controls fed varying doses of eggs, worm sizes were inversely related to the number of eggs in the challenge dose. Measurements of worms from vaccinated animals showed that 23 of 116 adult worms recovered were probably survivors of one or more of the vaccinating doses. A ratio of 18 female to 5 male worms indicated that males are more susceptible to ultraviolet radiation than females.

Animals↗
PubMed1978

The Schistosoma japonicum egg granuloma. II. Cellular composition, granuloma size, and immunologic concomitants.

Studies of granulomatous hypersensitivity to Schistosoma japonicum eggs were performed at various time periods up to 20 wk after the induction of light infections in mice. Cell populations which were determined in granulomas isolated from the livers revealed a maximum in the total number of cells at 6 wk with a decline of 36% by 20 wk. Large mononuclear cells were predominant at all time periods, with eosinophils being the second most common cell. Measurements of granuloma diameters around single viable eggs in the livers also revealed peak size at 6 wk with a decline of 51% between 16 and 24 wk. Immunodiffusion analysis demonstrated the presence of precipitating antibodies as early as 7 wk after infection. Investigations of lymphocyte blastogenesis revealed a profound depression in response to T-cell mitogens by 8 wk of infection. Studies of footpad swelling to soluble S. japonicum egg antigens revealed massive immediate reactions starting at 6 wk. but no delayed reactivity over a period from 3 to 20 wk. All of these results are related to differences in the biology of S. japonicum in comparison with S. mansoni with respect to the earlier onset of egg production, the much larger numbers of eggs produced, and the possibility of differences in the antigens emitted by the eggs.

Animals↗
PubMed1978

Role of shell diffusion area in incubating eggs at simulated high altitude.

Embryonic development is inhibited when eggs are incubated at 9,100 m (0.3 atm) despite a normoxic environment. The problem apparently relates to respiratory gas exchange occurring by diffusion through gas-filled pores in the shell. Gaseous flux is therefore inversely proportional to ambient pressure and is affected by the physical characteristics of the ambient gas (Chapman-Enskog equation). Excess loss of H2O and CO2 occurs in eggs incubating at altitude and could be detrimental. Such increased loss should be correctable by decreasing diffusion area. This was tested by progressively increasing coverage of the shell with paraffin and incubating at simulated 0.3 ATA (225 Torr) in 100% O2. Uncoated eggs failed to hatch, but numbers of chicks increased with increased coverage. Maximum hatch was an extrapolated 90% of controls at 69% shell coverage. With further coverage, hatch size decreased. Egg weight loss, and estimate of H2O diffusion, was around three times controls in uncoated eggs but decreased linearly with paraffin coverage, reaching near normal at maximum hatch. Reduction of diffusion area to 0.3 normal at maximum hatch generally balanced the increased flux predicted for 0.3 ATA.

Adaptation, Physiological↗
PubMed1979

Water-vapor conductance of testudinian and crocodilian eggs (class reptilia).

Flexible-shelled eggs of snapping turtles (Chelydra serpentina) have conductances to water vapor that are 55 times higher than predicted for avian eggs of similar size, whereas rigid-shelled eggs of softshell turtles (Trionyx spiniferus) and American alligators (Alligator mississippiensis) have conductances that are only five times higher than expected for comparable eggs of birds. The differences between empirical and predicted values result from the much higher effective pore areas in reptilian eggshells than in those of birds. The relatively high porosities of these reptilian eggs presumably facilitate the transport of oxygen and carbon dioxide eggshells in later stages of incubation when air trapped inside nest chambers may become hypoxic and hypercapnic, yet seem not to lead to excessive transpiration of water vapor owing to the high humidities in nests where incubation occurs.

Alligators and Crocodiles↗
PubMed1979

[Teratogenic effect of dicrotophos on the embryonic chick tibia ; histological and cytological studies (author's transl)].

The organophosphorus insecticide dicrotophos injected at 4 days of incubation into the yolk sac of hen'eggs determined achondroplasia with tibiotarsus deformities. These malformations were studied at different stages of embryogenesis using different histological methods. After injecting 0,5 mg per egg, the size of the hindlimbs was decreased by 50% and the growth was much less (from 20 to 30% of the normal) When giving the toxic et the level of 1 mg per egg. Light and electron microscopical observations showed a reduction or a lack of the proliferative zones and a decrease in the secretory activity of the chondrocytes which may possibly be related to the growth retardation. Using adaptated techniques for mineralized tissue examination and scanning microscope, a disorganized and an asymmetrical deposition of the periosteal osseous lamellae was observed.

Animals↗
PubMed1977

Influence of immunosuppressants on the establishment of Paragonimus miyazakii in albino rats.

The present investigation has shown that combined treatment with dexamethasone and prednisolone of with hydrocortisone and dexamethasone enhances the susceptibility of albino rats to Paragonimus miyazakii, presumably by suppressing the host's immune responses. In the rats given these combined treatments, the size and egg production of worms were markedly increased. Use of dexamethasone or prednisolone alone had relatively little influence on the growth and maturity of P. miyazakii. In serological analysis and agar double diffusion, considerable differences were recognized between the gamma-globulin fractions and antigen-antibody systems (precipitin bands) of the treated groups and the untreated group. The mechanism of action of these immunosuppressants in this system remains obscure.

Animals↗