bluuebunny/crossref_metadata_2025_split huggingface dataset:
Behavioral studies of inhibition and integration in the mosquito Culiseta inornata (Williston)
Authors: Owen William B. 
Published: June 2005

AbstractA study was made of the interaction in the central nervous system of sensory input arising from the simulatneous application of opposing stimuli to receptors on the tarsi and labella of the mosquito. Stimulating chemosensory hairs on the tarsi with 5 M NaCl failed to inhibit the labeller response to sucrose at concentrations above 0.125 M. At lower sucrose concentrations there was a decrease in the number of mosquitoes responding. The application of 5 M NaCl to the tarsal receptors elevated the labellar threshold for sucrose in all subjects tested. This influence of the salt was expressed whether acting on the tarsi in an ipsilateral or contralateral manner. Stimulating the tarsal hairs with 2 M sucrose resulted in a labellar response to NaCl at concentrations of 0.50 M and lower. Ordinarily NaCl is rejected at all concentrations by this mosquito. Evidence was obtained which indicated that the labellar response to NaCl was mediated by the water receptor rather than by the salt receptor.
The osmotic behavior of digestive cells of Chlorohydra viridissima
Authors: Koblick Daniel C. , Yu‐Tu Lorna 
Published: June 2005

AbstractDigestive cells of Chlorohydra viridissima undergo reversible volume changes when suspended in varying concentrations of sucrose. The cells are isotonic to 50 mM sucrose. At sucrose concentrations higher than 200 mM volume changes are ideal, and correspond to an osmotically inactive volume of 0.71. Below 200 mM, deviations from ideal behavior occur; these indicate the development of an intracellular hydrostatic pressure, which reaches a maximum at about 50 mM. Below this concentration, the pressure remains constant. When suspended in culture medium these cells assume a prolate spheroid shape with axial ratio 0.75 ± 0.07.In sucrose solutions, the axial ratio undergoes systematic changes; as the sucrose concentration is reduced, the axial ratio slowly increases to a maximum value between 50 and 70 mM. On further dilution of the culture medium it drops rapidly. These shape changes are discussed in terms of the osmotic volume changes observed.
Nucleic acid and protein synthesis in melanocytes of Amphiuma liver: A radioautographic study
Authors: Prasad Kedar N. 
Published: June 2005

AbstractNucleic acid and protein synthesis was studied in the melanocytes and hepatocytes of the liver of Amphiuma with H3 thymidine, H3 cytidine and H3 leucine. In this organism, the hepatic melanocytes are highly pigmented (containing an abundance of melanin‐containing organelles, polymelanosomes), have only a small area of non‐pigmented cytoplasm (containing smooth endoplasmic reticulum and no polymelanosomes). The presence of polysomes in both pigmented and non‐pigmented areas could not be demonstrated.Only an occasional melanocyte and 2% of the hepatocytes were labeled with H3 thymidine. Rate of RNA metabolism in melanocytes was slower than in hepatocytes. Actinomycin D had no significant effect on nuclear incorporation of H3 cytidine in melanocytes, but it inhibited nuclear uptake in hepatocytes by 86% of controls. Cytoplasmic incorporation of H3 cytidine in both cell types was insensitive to actinomycin D treatment.Protein synthesis, as based on H3 leucine uptake, was less in the pigmented areas than in non‐pigmented ones. Although protein synthesis on the basis of grain count/cell appeared greater in hepatocytes than in melanocytes, the density of grain count was equal after correction for differences in cell size. The incorporation of H3 leucine was not reduced in the melanocytes or the hepatocytes 96 hours after actinomycin D treatment.
Micrurgical experiments on cytokinesis in Stentor coeruleus
Authors: Tartar Vance 
Published: June 2005

AbstractCutting and grafting experiments on the ciliate Stentor coeruleus during division stages indicated or demonstrated the following: (1) Unequal division after excision of one cell end showed that the location of the fission line usually remains predetermined but this line is not an indispensable constriction organelle. (2) The fission line is always smooth in spite of irregularities in the cell surface and it cannot extend across gaps. (3) A transequatorial piece of a divider can go on to divide anywhere on a divider in the same stage of division but its fission is not autonomous because it can be affected if the host cell is in a very different stage of division or is a non‐divider. (4) After removing half the presumptive or actual fission line or furrow a stentor can still divide along the line of healing. (5) Transverse cuts, though resembling a division line, do not serve for fission. These results suggest a morphogenetic hypothesis of cell division in Stentor.
Chronic skin graft rejection in the urodela. I. A comparative study of first‐ and second‐set allograft reactions
Authors: Cohen Nicholas 
Published: June 2005

AbstractUnlike acute skin allograft reactions observed in most randomly breeding ectothermic and endothermic vertebrates, a basic pattern of intermediate to prolonged chronic skin graft rejection characterized the alloimmune response of representatives of at least five genera of salamanders from three different families (Salamandridae, Ambystomatidae, and Proteidae). First‐set median survival times (MST's) ranged from 33 to 55 days at 25°C. Individual zero end points (total melanophore destruction) occurred between 17 and 120 days. Several grafts appeared to have survived indefinitely (> 300 days) with full to partial viability.MST's of second‐set grafts were significantly shorter than first‐set MST's for all salamanders except Ambystoma tigrinum. For this species, the small sample of seven repeat grafts all exhibited either prolonged survival vis‐a‐vis first‐set grafts or were destroyed well within the range of first‐set rejections. About 25% of the combined individual Taricha and Necturus repeat grafts were completely destroyed at the same postoperative time as or significantly later than first‐set grafts from the same donor. Only curtailed survival of Cynops second‐set grafts was noted. When the post transplantation period was resolved into a latent phase and a rejection phase, the curtailed survival of 50% of the Traricha and 60% of the Cynops second‐set grafts was attributable solely ot a comparatively shorter latent period. The curtailed zero end points of other Taricha repeat grafts resulted from both shorter latent and shorter rejection intervals. The overall prolonged second‐set survival noted for some Taricha allografts was referable only to longer rejection phases; the latent phases for these repeat grafts were either shorter than or similar to those of the corresponding primary grafts.
Reversible developmental arrest in the embryo of the zebrafish, Brachydanio rerio
Authors: Laale Hans W. , McCallion David J. 
Published: June 2005

AbstractZebrafish embryos at six developmental stages were exposed to the supernatant of homogenates of zebrafish embryos, 5‐day chick embryos and 9 mm frog larvae. Extracts of embryos bring about developmental arrest of the zebrafish embryo at stages 17–18. The effect is reversible. Arrested embryos returned to buffered water recover and develop normally to hatching, delayed by a time equal to the time of exposure to extracts. Two fractions of the embryo extract are produced by G‐75 Sephadex gel filtration. The inhibitory effect is limited to one of these fractions. The inhibitory factor in embryo extract has characteristics compatible with those of nucleases but the effect on embryos is unlike that of ribonuclease.
Mechanism of the pleiotropic effects of the short‐ear mutant gene in the mouse
Authors: Green Margaret C. 
Published: June 2005

AbstractThe recessive mutant gene short‐ear (se) reduces the rate of proliferation of precartilage cells, producing a skeleton of reduced size with numerous small defects. It also reduces the rate of proliferation of callus cells in healing bone fractures. In this study se was shown not to affect rate of regeneration of liver, thymus, or connective tissue.Short‐eared mice have many anatomical abnormalities of the soft tissues including medial displacement of the left gonad, ventral displacement of the right renal artery, hydroureter and hydronephrosis, giant cell granulomas on the ventral surface of the liver, and on some genetic backgrounds an increased frequency of cysts of the lungs. Young se/se mice often have neuromuscular waviness of the tail. In the heterozygous condition (+/se) the gene causes a slight reduction in skeletal size and a slight increase in frequency of hydroureter, liver lesions, lung cysts, and wavy tail. It was shown that the viscera appear to be crowded from the 11‐day stage of gestation and that crowding is probably responsible for the abnormalities of the left gonad, the right renal artery, and the ureter, and is possibly a contributing cause of the granulomas of the liver. The probable cause of the crowding is the slower growth of the skeleton, resulting in a body cavity too small to accommodate the visceral mass of normal size. It is not clear that crowding is a sufficient explanation of the liver lesions or that it explains the effect of se on frequency of lung cysts or on waviness of the tail.
Oogenesis in the suppressor2 of hairy‐wing mutant of Drosophila melanogaster. I. Phenotypic characterization and transplantation experiments
Authors: Klug William S. , Bodenstein D. , King R. C. 
Published: June 2005

AbstractCytological studies of ovaries from Drosophila melanogaster homozygous for the female sterile gene, su2‐Hw, demonstrate that the nurse cell components of the egg chambers are primarily affected. The chromosomes of these endopolyploid cells remain condensed, whereas the normal polytene chromosomes of wild type nurse cells uncoil and fall apart prior to vitellogenesis. Vitellogenesis is greatly inhibited in the mutant, and the egg chambers eventually degenerate. Reciprocal transplantation experiments show autonomous behavior of + and su2‐Hw ovaries. Therefore the ovarian phenotype is due to the action of the mutant gene in the ovarian cells themselves.
Polar granules of Drosophila. II. Ultrastructural changes during early embryogenesis
Authors: Mahowald Anthony P. 
Published: June 2005

AbstractPolar granules of Drosophila show distinctive variations in structure at various stages of early embryogenesis and in different species. In most species they are attached to mitochondria at fertilization, then they become free and fragment during the cleavage divisions and during the time of pole cell formation. After pole cells have formed they again coalesce. At the time of migration of the pole cells to the embryonic gonad, the polar granules again fragment and become attached to the outer membrane of the nuclear envelope.Ribosomes are attached to the periphery of polar granules at the time they are fragmented prior to and during pole cell formation. An hypothesis is presented on the basis of published reports of RNA present in the granules and the ultrastructural observations reported here. This hypothesis suggests that the RNA in polar granules is m‐RNA that directs the synthesis of those proteins necessary for the determination of the pole cells to become germ cells.
Histological and ultrastructural study of the muscular and nervous systems in Hydra. I. The muscular system and the mesoglea
Authors: Haynes Julian F. , Burnett Allison L. , Davis Lowell E. 
Published: June 2005

AbstractThe myonemes of the epithelio‐muscular cells of Hydra viridis were studied with the electron microscope. The myonemes are formed from fibers running parallel to the long axis of the polyp. The myoneme is a mixture of thick (200 Å diameter) filaments and thin (60 Å diameter) filaments. There was no indication of regular organization or spacing of the filaments. The filaments were attached to the membranes of the epithelio‐muscular cells at their ends. In these regions there were junctions between adjacent cells similar to the intercalated discs of vertebrate cardiac muscle. The possible role of these junctions in the transmission of an impulse along the length of the body column is discussed.The mesoglea consists of organized fibers dispersed in an amorphous ground substance. The pattern of organization of the fibers of the mesoglea is possibly a spiral and may be responsible for some of the morphogenic phenomena in Hydra which follow a spiral pattern.
Quantitative evaluation of individual variability in the heat‐resistances of cells and their contractile models
Authors: Ushakov B. , Amosova I. , Pashkova I. , Chernokozheva I. 
Published: June 2005

Abstract
Evaluation of thermostability by the time required to inactivate cells and models at a constant temperature reveals significant differences between specimens from the same population.
The analysis of statistical distribution of the thermostabilities of cells and cellular models shows that it is advantageous to treat the logarithms of the inactivation times rather than the numerical values themselves. (a) The distribution curve in this case is symmetric while that of the numerical values for some of the objects studied is an asymmetric one, and (b) the value of variance of logarithm distribution does not depend on the temperature at which the heart‐resistance is measured.
Standard deviation or distribution variance of logarithms of inactivation times of cells and models may be used as quantitative criteria of intrapopulational variability in heat‐resistance. When comparing variabilities in the heat‐resistance of non‐homologous cells and models, special attention should be paid to the possible effect of methodological factors on the total magnitude of the variance or standard error.
Frequency curves of the thermostabilities of cells and models exhibit only a single maximum and have a continuous character which may indicate polygenic inheritance of heat‐resistance.
Correlated physiological and ultrastructural studies on specialised muscles. Ic. Neuromuscular junctions in the eyestalk levator muscles of Podophthalmus vigil (Weber)
Authors: Hoyle Graham , McNeill Patricia Ann 
Published: June 2005

AbstractThe ultrastructure of physiologically different motor nerve terminals on fibers of the eye‐raising muscle of the crab Podophthalmus vigil is described. The terminals occur wherever branching axons lose part or all of their Schwann cell cover, either in simple grooves on the surface, in invaginated clefts, or even deep within the fiber in invaginated fingers lined by extension from the surface plasma membrane of the muscle fiber. Dense innervation of the surface of the fiber is associated with the occurrence of large, non‐facilitating e.p.s.ps., i.e., with “fast” axons. Less dense innervation, with deeply invaginated terminals is associated with small‐sized e.p.s.ps. and with facilitation typical of “slow” axons. No differences in either vesicle content, vesicle shape, mitochondrial density or density of other particles could be found in terminals having different associated biophysical properties.
Effect of calcium on the structure and functional response of the starfish ovary to radial nerve factor
Authors: Schuetz Allen W. , Biggers John D. 
Published: June 2005

AbstractThe effects of calcium‐free sea water (CaFSW) on the starfish ovarian structure and on ovarian responsiveness to radial nerve factor (RNF) were studied following in vitro incubation. Incubation of ovaries in CaFSW resulted in a progressive elongation of the entire ovary and the dispersion of follicular cells from around the oocytes contained within the ovary. The changes in ovarian length but not the follicular cell detachment were reversible when ovaries were placed in sea water containing calcium. Addition of Mg++ or Na+ to CaFSW did not prevent ovarian elongation or follicular cell dispersal. Strontium ions prevented and reversed ovarian elongation when added to CaFSW; however, follicular cell dispersion was not inhibited. The oocyte shedding, normally induced by RNF, was prevented by maintaining the ovary in CaFSW. The degree of shedding inhibition was dependent upon the duration of washing in CaFSW. RNF did not prevent or reverse the ovarian elongation induced by CaFSW. The inhibitory action of CaFSW on RNF‐induced oocyte shedding could be reversed by the addition of Ca++ or Sr++ but not by the introduction of Mg++ or Na+. The degree of reversibility was dependent upon the concentration of Ca++ ions. The data strongly indicate that contractile tissue in the ovarian wall is important in mediating oocyte shedding in response to RNF.
Genic control of cortical pattern in Euplotes
Authors: Heckmann Klaus , Frankel Joseph 
Published: June 2005

AbstractThree inter‐fertile wild races of Euplotes minuta, which differ with respect to the maximal number of kineties expressed in a clone, were subjected to a breeding analysis. The data obtained in this analysis suggest a genic control of the differences in cortical pattern. Evidence for the operation of a cytotactic mechanism for short‐term perpetuation of kineties was also obtained.Investigation of cellular features, possibly related to the mode of action of this genic control, established no direct relationship between kinety number and fission rate or cell size. Some evidence was, however, found for a genic control of the total number of kinetosomes, and this might be related to the control of the number of kineties. A mechanism, by which kineties are gained and lost, is proposed and evidence for this mechanism is provided.The relation between cytotaxis and the genic control of the range of kinety number is discussed, and the conclusion is reached that cytotaxis helps to perpetuate existing surface patterns, whereas long‐range control of the most stable kinety number is nevertheless genic.
Effect of short‐ and long‐term hypophysectomy on the ovary and interrenal of catfish, Heteropneustes fossilis (Bloch)
Authors: Sundararaj Bangalore I. , Goswami Shashi V. 
Published: June 2005

AbstractCatfish were hypophysectomized during the late prespawning period when the ovaries are enlarged with yolky oocytes, and autopsied at close intervals to ascertain the short‐term effects of hypophysectomy. A significant reduction in the ovarian weight occurs between day 4 and day 6 post‐hypophysectomy. Thereafter, the ovarian weight declines rapidly and the lowest value is attained by day 35 post‐hypophysectomy. Hypophysectomy induces atresia of yolk‐laden oocytes and the sequence of changes in an atretic oocyte involves the coalescence of yolk plateletes, breakdown of vitelline membrane, hypertrophy of granulosa cells which quickly phagocytose the yolk, and the eventual merger of masses of granulosa cells in the ovarian stroma. Hydration of the ovaries gradually increases following hypophysectomy and the maximum value is attained by day 19 post‐hypophysectomy when follicular atresia is greatest, and returns to normal by day 49. Hydration of muscles remains almost constant despite hypophysectomy. In the interrenals, the post‐hypophysectomy changes involve leucocytic infiltration, gradual reduction in the nuclear diameter of cortical cells and condensation of chromatin.In the long‐term study, catfish were hypophysectomized during the preparatory period when the ovaries are regressed, and autopsied one and two years post‐hypophysectomy. The ovarian histology of catfish sampled one and two years following hypophysectomy was similar to that of their respective controls inasmuch as sampling was also done in the preparatory period, whereas the interrenal histology was markedly different from that of the controls. In the interrenals of hypophysectomized groups, leucocytic infiltration was more in evidence and the cortical cell nuclear diameter showed significant reduction.
Cytological and ultrastructural comparisons of t12/t12 and normal mouse morulae
Authors: Calarco Patricia G. , Brown Edward H. 
Published: June 2005

AbstractCytological and ultrastructural observations were made of normal (BALB/c) mouse morulae and embryos homozygous for the t12 mutation, which is lethal at the late morula stage. Normal and t12/t12 embryos are indistinguishable cytologically until the late morula stage, at which time cytoplasmic and nuclear differences become apparent. Different cells within individual normal morulae exhibit differences in cytoplasmic basophilia, and the cells appear closely applied to one another. Differences in cytoplasmic basophilia are not apparent between different cells of t12/t12 morulae, and the cells appear more rounded and less closely applied. Nucleoli of normal morulae are irregular in shape, with projections which often reach the nuclear envelope, while nucleoli of t12/t12 morulae exhibit extreme rounding.Nucleoli of normal embryos exhibit a net‐like nucleolonema, with fibrillar and granular elements, and several pars amorpha. Nucleoli of t12/t12 morulae possess the same structural elements but the nucleolonema appears contracted. Nuclei of mutant embryos often contain several agranular electron‐dense bodies, 0.1–0.7 μ in diameter. These are infrequently observed in normal morulae. Ribosomes exist primarily in clusters in normal morulae, but large numbers of free ribosomes are observed in t12/t12 morulae. Many structures are common to both normal and mutant morulae, such as: fibrous strands, crystalloids, granular endoplasmic reticulum, vacuolated mitochondria, cytoplasmic vesicles, tight junctions, nuclear pores, and intranuclear annulate lamellae.Since the abnormalities exhibited by t12/t12 morulae can be interpreted as degenerative changes, they do not resolve the mode of action of the t locus or the primary cause of t12/t12 lethality.
The fate of desmosomes in trypsinized tissue
Authors: Overton Jane 
Published: June 2005

AbstractEmbryonic animal epithelial tissue in which desmosomes are well developed has been dispersed by trypsinization and the behavior of desmosomal halves observed. An earlier report left open the question of whether desmosomes were broken down or reincorporated into the reorganized tissue. A more detailed study shows that dispersed cells, or cells which are partially separated, phagocytize half desmosomes left at the cell surface. The resulting vacuoles are angular during early stages of the process indicating that desmosomes are relatively rigid. They later become spherical and characteristic desmosomal morphology disappears. These results are discussed in connection with morphology in genetic disturbances and in development.
A yellow variant of the eumycetozoan Didymium nigripes which exhibits aging
Authors: Kerr Norman S. , Waxlax Judith N. 
Published: June 2005

AbstractA cycloheximide‐resistant, yellow variant of the true slime mold, Didymium nigripes, has been isolated. It exhibits aging as exemplified by a loss of ability to fruit, fuse with other plasmodia, and grow. It is often rejuvenated after fruiting or being present in a heteroplasmodium with the wild type. The behavior of subclones was very variable, but the behavior of populations of clones was predictable.
Blastular arrest and chromosome abnormalities produced by x‐rays in two amphibians: Rana pipiens and Xenopus laevis
Authors: Ursprung Heinrich , Leone Janet , Stein Louis 
Published: June 2005

AbstractProduction of chromosomal abnormalities by x‐raying Amphibian zygotes is not necessarily followed by blastular arrest. At an x‐ray dose that produces blastular arrest in 20% of the irradiated embryos, over 90% of the embryos were found to contain cells with gross chromosome aberrations.Different pregastrular stages are differentially sensitive towards x‐ray production of blastular arrest.