bluuebunny/crossref_metadata_2025_split huggingface dataset:
The fate of sperm middle‐piece mitochondria in the rat egg
Authors: Szollosi Daniel 
Published: June 2005

AbstractMitochondria of rat sperm tail middle‐piece remain associated with the flagellum after penetration of the egg by the spermatozoon and during the time of the first cleavage. During two‐ to four‐cell stages the middle‐piece mitochondria gradually swell while they separate in large clusters from the axial filament. The swelling of the male mitochondrial elements becomes more extreme during the cleavage divisions, and they finally seem to disintegrate. Thus all mitochondria found in the developing rat embryo may originate from the egg.
Yeast dosage level and the postembryonic survival and growth of the carp Labeo rohita (Ham.)
Authors: Das B. C. 
Published: June 2005

AbstractThe effects of yeast dosage level upon the survival and growth of postembryonic Labeo rohita, a major Indian freshwater carp, were investigated. Two identical experiments were conducted on 37,827 and 26,903 one‐day‐old carp respectively. In each experiment the carp were allocated to 60 experimental units, each containing nine liters of water. The units were assigned to six yeast dosage levels according to a randomized block design, with ten replications of each level. Dosages of 0, 0.5, 1.0, 2.0, 3.0 and 4.0 g yeast daily were employed. Data were collected for survival, as daily proportion surviving, and growth, as daily dry weight, for the carp from 3 to 20 days of age. Statistics describing the regression of survival and of growth on age were computed for the different dosage levels and compared statistically by “Student's” t. Survival and growth were both significantly (P < 0.01) enhanced by yeast treatment. Comparison of dosage levels showed that yeast enhanced survival in a qualitative all‐or‐none manner and growth in a quantitative manner. These results suggest that, in postembryonic carp, survival may be influenced by the vitamins in yeast while growth may be enhanced by its amino acid content.
Experiments dealing with the inhibition and release of lens regeneration in eyes of adult newts
Authors: Stone L. S. 
Published: June 2005

AbstractNine groups of experiments on 537 eyes of adult newts, Triturus v. viridescens, examined conditions under which lens regeneration is inhibited or released from dorsal iris tissue. The lens is quite vulnerable for it degenerates when the lens capsule is injured and when the neural retina degenerates following a temporary loss of blood supply. Degeneration of neural retina in lentectomized eyes delays lens regeneration from both implanted and host dorsal iris. If degeneration of neural retina is induced after lens regeneration begins its further development is temporarily retarded until the neural retina proceeds to regenerate.If one of two large lens regenerates in a single eye is removed, one from the host eye or one from an implanted segment of dorsal iris, the surviving lens inhibits further lens regeneration from any dorsal iris tissue present. Two dorsal halves of eyes can be fused into one normal appearing unit which regenerates two lenses, one from each half. When one lens is removed the remaining lens inhibits lens regeneration from either half in the environment of a normal amount of neural retina.If a plastic membrane is implanted to divide the upper and lower halves of the eye into two separate chambers, each with its own aqueous humor and half of the neural retina, lens regeneration from the isolated iris above is no longer inhibited by the intact normal lens below.
Induced division and division regression by cell fusion in stentor
Authors: Tartar Vance 
Published: June 2005

AbstractCiliates dividing and not dividing were fused by cell grafting to characterize, by the interactions, cell states during division and interdivision. Control grafts of divider × divider showed that the operation itself was unimportant for the results (contrary to Weisz, '56). In the majority of cases the trophic component of a graft induced primordium resorption and regression of division in the divider. Thus it appears that trophic stentors actively inhibit their own division with a blockage that can extend to a conjoined divider. That disinhibition is the onset of division and persists only until division is assured was indcated by the findng that both late dividers and predividers can induce division regression. Only in grafts precisely balanced with respect to relative sizes of the partners and division stage of the divider did dividers induce direct division of fusion partners that would not otherwise have divided. In fork‐tailed stentors both cell bodies divide although a division primordium appears in only one.
Pigment cell development after exchange of neural folds between the california newt and the mexican axolotl
Authors: Duncan James T. 
Published: June 2005

AbstractTrunk neural folds from both black and white axolotls, Ambystoma mexicanum, were transplanted unilaterally in place of folds of Taricha torosa neurulae. Melanophores from either kind of axolotl completely suppress the differentiation of T. torosa melanophores for several stages and largely suppress it for much longer. During larval stages host pigmentation gradually develops, but axolotl pigmentation always dominates. After metamorphosis the typical Ambystoma spotted pattern appears. During all stages donor melanophores are almost equally distributed on both flanks, with only slightly more on the grafted side. Guanophores predominate on the grafted side, while xanthophores predominate on the opposite side. With the exception of the distribution of axolotl melanophores, these results confirm results of others with the black axolotl and offer additional evidence that the chromatophores of both black and white axolotls are equivalent. New suggestions are made to explain the unequal distribution of xanthophores and guanophores in view of the nearly equal distribution of axolotl melanophores.Trunk neural folds of T. torosa were transplanted bilaterally in place of white axolotl neural folds. The typical T. torosa larval pigment pattern is expressed in the grafted area, but host melanophores suppress donor melanophores beyond the confines of the graft. Eventually all axolotls immunologically rejected their neural crest grafts. Only 13% of the T. torosa rejected their grafts. These results confirm that T. torosa has a much greater tolerance to grafted foreign tissue than do axolotls. The immunological behavior of these animals is discussed in the context of results of similar experiments in anurans.
Some relationships between Chlorohydra, its symbionts and some other chlorophyllous forms
Authors: Park Helen D. , Greenblatt Charles L. , Mattern Carl F. T. , Merril Carl R. 
Published: June 2005

AbstractTwo species of Chlorohydra, two free‐living algae and a green flagellate were used to investigate the following: (1) Removal of algal symbionts, (2) reinfection of albinized hydra, (3) autonomy of the partners once separated, (4) infection of albino hydras by algal symbionts from another species of Hydra and by free‐living algae and a green flagellate.C. viridissima could not be albinized by the usual methods, while C. hadleyi was easily albinized. The albino form could be reinfected easily by injection and grafting methods but it could not readily be infected with symbionts from C. viridissima. One free‐living alga (Oocystis) gave limited infection after injection of the algal cells into albino hydras. Survival of green and albino forms of C. hadleyi under starvation conditions was the same but budding rate of the albino form was higher than that of the green form. Attempts to maintain continuous cultures of the green symbionts in vitro were unsuccessful, but with a specially devised method it was shown that the algae survived at least 14 days in an artificial medium.
A comparative study on avian adrenocortical response to exogenous and endogenous corticotropin
Authors: Bhattacharyya T. K. , Sarkar A. K. , Ghosh A. , Ganguli A. 
Published: June 2005

AbstractThe transient effects of exogenous ACTH and unilateral adrenalectomy on the adrenal weight, histology, adrenal cholesterol and ascorbic acid were studied in several adult avian species. A single injection of ACTH produced a significant depression of adrenal ascorbic acid (AAA) in the pigeon (Columba livia), the egret (Bubulcus ibis) and the myna (Acridotheres tristis). A fall in AAA was encountered in the unilaterally adrenalectomised pigeon and myna. A depletion of adrenal cholesterol induced by temporary ACTH treatment was noted in the pigeon, the egret and the myna; unilateral adrenalectomy produced a cholesterol depletion in the myna but not in the pigeon. Adrenal weight studies were not corroborative but there was a histological response of the interrenal in various treatments.
Differential genic activity in Paramecium aurelia
Authors: Pasternak J. 
Published: June 2005

AbstractAn autoradiographic analysis of macromolecular syntheses in the micronucleus of Paramecium aurelia was undertaken to discover whether the micronucleus was completely inert. There is a distinctive temporal ordering of micronuclear macromolecular synthesis during the fission cycle. DNA synthesis is limited to the 47‐69% portion of the fission cycle. There is an initiation of a rise in RNA and protein synthesis that precedes DNA synthesis. Between 45‐65% of the fission cycle, all three biosyntheses are concomitant and reach maximal activity.Cells with micronuclei but no macronucleus were obtained by employing the “amac” mutant. Micronuclei in amacronucleate cells were able to synthesize RNA. Pulse labeling experiments provided evidence that the micronucleus synthesizes RNA in situ.Actinomycin D inhibits micronuclear RNA and DNA synthesis temporarily, whereas micronuclear protein synthesis is hardly affected. Chloramphenicol delays the onset of micronuclear DNA biosynthesis and blocks the rise in RNA synthesis; micronuclear protein synthesis is reduced but never to an undetectable level. The data suggests that RNA and protein syntheses are required for the initiation of micronuclear DNA synthesis.The micronucleus shows an enhanced rate of RNA synthesis during serotype transformation.To test for genic activity in the micronucleus heterocaryons were constructed. When certain genes are present in the micronucleus only, they are not able to efficiently support the phenotype which these genes control when they are present in the macronucleus.It is concluded that the micronucleus is not a completely inert nucleus.
Diploid and haploid hybridization of different populations of the Rana pipiens complex. II. Experiments with females from Oklahoma
Authors: Moore John A. 
Published: June 2005

AbstractDiploid hybrids and androgenetic haploid hybrids have been made with eggs of Rana pipiens from Oklahoma and sperm of males from Oaxaca (Mexico), Arizona, Texas, Louisiana, South Carolina, Tennessee, Delaware, and Vermont. The diploid hybrids were normal or nearly so in all crosses except with the Texas males. The haploid hybrids of crosses with Oaxaca, Arizona, and Texas males were highly abnormal; with Vermont and Delaware males they were less abnormal; with Louisiana, South Carolina, and Tennessee males they were normal. Haploid hybridization seems to be more sensitive than diploid hybridization in detecting compatibilities between the gametes of two populations. It can contribute to an understanding of evolution and systematics within the Rana pipiens complex.
Prehatching motility and hatching behavior in the chick
Authors: Hamburger Viktor , Oppenheim Ronald 
Published: June 2005

AbstractIn previous communications, the motility of the chick embryo up to 17 days of incubation had been characterized as spontaneous rhythmical uncoordinated random motility. On the other hand, the opening of the shell and hatching are accomplished by a sequence of vigorous back thrusts of the head and beak against the shell. The head movments are part of a coordinated action pattern which includes wriggling movements of the body which have a rotatory component, resulting in the rotation of the body along its axis; and the bracing of the shoulder and tarsal joints against the shell.We have found that similar coordinated movements including a rotatory component are instrumental in several other action patterns which are preparatory to hatching. They include: the lifting of the head out of the yolk sac; the tucking of the head under the right wing; the assumption of the typical hatching position; and pipping. Another preparatory step, namely the penetration of the membrane separating the embryo from the air space does not require coordinated movements. All these movements were observed through windows in the shell; they are described in detail.Coordinated movements appear to originate de novo around day 17. They do not seem to be related to the random movements which are characteristic of earlier embryos. The latter continue until the onset of hatching, but they are suspended temporarily while the coordinated movements are performed during tucking, pipping and hatching.
Fine structure analysis of oogenesis in sea urchins
Authors: Millonig Giuseppe , Bosco Maria , Giambertone Liliana 
Published: June 2005

AbstractThe changes in fine structure of the growing female germ cell of Arbacia lixula and Paracentrotus lividus were examined by light and electron microscopy. During the previtellogenic growth stage of the oocyte, when the ribosome population in the cytoplasm increases several thousand times, the nucleolus also increases considerably in volume. A large number of ribosome‐like granules are concentrated in these nucleoli. Although particularly during this stage a passage of “informative” material from the nucleus to the cytoplasm is to be expected, at present, evidence of any kind of extrusion has not been observed in these species. The only indirect morphological evidence for passage of material out of the nuclei might be the many newly formed pore complexes in the nuclear envelope. There is, however, strong evidence that they do not represent patent openings, since a dense, almost homogeneous, material is observed within the pore. Thus it is assumed that small molecules might pass through the pores freely, but not large particles the size of ribosomes.Dense aggregates of two different types have been observed in secondary oogonia and in oocytes at the growth stage: one shows densely packed fibrils of about 80 Å and the other granules of 300 to 400 Å.At the end of vitellogenesis, the major nucleolus becomes vacuolated and disappears. At the same time several minor “agranular” nucleoli are formed. At meiosis these too disappear. In the mature egg few “agranular” nucleoli are seen. During cleavage the several “agranular” nucleoli are fibrillar, without ribosome‐like granules. From the blastula stage on, at a time when the cell divisions stop almost completely, the one or two nucleoli which can be observed in each nucleus have a small number of granules. During the following development the number of granules increases gradually up to gastrula, whereas the number of fibrils becomes more and more reduced.
The lactate dehydrogenase isozymes of twelve species of flatfish (Heterosomata)
Authors: Lush I. E. , Cowey C. B. , Knox D. 
Published: June 2005

AbstractThe starch gel electrophoresis patterns of lactate dehydrogenase (LDH) from various tissues of 12 flatfish species belonging to 3 families are described. In 10 species belonging to the families Pleuronectidae and Bothidae, most tissues have a single major LDH isozyme. The central nervous system and retina show more complex patterns. Two species belonging to the Soleidae do not possess major tissue‐specific LDH isozymes in central nervous system and retina. Some properties of the LDH isozymes from the skeletal muscle, heart, brain and retina of the plaice are described. The LDHs of muscle and heart appear to be identical. The major tissue‐specific isozyme of retina accounts for almost 40% of the LDH activity in that tissue in the plaice. The difficulties in the way of using LDH zymograms to deduce the evolutionary relationships of the Heterosomata with other teleosts are discussed.
Inhibition of fertilization and production of heteroploidy in eggs of mice treated with colchicine
Authors: McGaughey R. W. , Chang M. C. 
Published: June 2005

AbstractFemale mice were injected with various doses of colchicine before or after induced ovulation and artificially inseminated. Their eggs were recovered and prepared according to an air‐dry method for the examination of chromosomes. In the unpenetrated eggs examined four and one‐half to six and one‐half hours after ovulation, the chromosomes were scattered throughout the ooplasm in the colchicine treated mice.When examined four and one‐half to six and one‐half hours after ovulation, only 7% of 353 eggs recovered from females injected with 0.5, 1.5 or 3.0 μg of colchicine/gm body weight earlier than three and one‐half hours after ovulation were penetrated, but 35% of 144 eggs from untreated females and 41% of 73 eggs from females given colchicine at three and one‐half hours after ovulation were penetrated. When examined 23 to 25 hours after ovulation 32% of 76 eggs from females treated before ovulation, 87% of 93 eggs from females treated at three and one‐half hours after ovulation, and 94% of 78 eggs from control females were penetrated.In 84% of 44 penetrated eggs from treated females their chromosomes were still at metaphase II while the sperm head had begun its transformation. By contrast, of 42 control eggs containing transforming sperm heads, 98% displayed anaphase or telophase of the second meiotic division.Chromosome counts of eggs at the first cleavage revealed heteroploidy ranging from the hypohaploid to the triploid condition and the absence of normal diploid eggs from treated females whereas the majority of eggs from control females displayed the diploid number of chromosomes (2n = 40).Four groups of rabbit eggs were recovered from does injected with colchicine before or after ovulation. Chromosome scattering and inhibition of fertilization were not observed. It appears that colchicine interferes with sperm penetration, the second meiotic division and normal cleavage in the mouse, but no effect was observed in the rabbit with similar dose levels.
Phylogenetic variation of rodent liver esterases
Authors: Holmes Roger S. , Massaro Edward J. 
Published: June 2005

AbstractLiver esterase zymograms of representatives of 21 species of rodents and of three inbred strains of Mus musculus are sufficiently variable to reflect species differences yet conservative enough for at least one group of esterases (the major liver carboxylesterases) to indicate phylogenetic relationships. The carboxylesterases of the Myomorph species exhibit a distinct multiple banding pattern. The species of Caviidae and Hystricidae also have characteristic patterns of esterase activity. Utilizing characteristics of the zymogram patterns such as degree of multiplicity, electrophoretic mobility, inhibitor specificity and heat lability of the major liver carboxylesterases, it is possible to arrange the rodent species into groups which are in accord with classical phylogeny. Studies of polymorphism of liver esterases from inbred strains of mice indicate that the multiple band phenotype of the major liver carboxylesterases is fixed or in high frequency in the population. Other carboxylesterases and the cholinesterases are variable within a species and would serve little use in phylogenetic comparisons.
A comparative physico‐chemical characterization of lactate dehydrogenase: Isozymes in brook trout, lake trout and their hybrid splake trout
Authors: Wuntch Thomas , Goldberg Erwin 
Published: June 2005

AbstractPeptide maps and amino acid composition of LDH crystallized from skeletal muscle extracts of brook trout (Salvelinus fontinalis) and lake trout (S. namaycush) are similar to those of the hybrid splake trout. The molecular weights are identical to mammalian LDH on the basis of sucrose density gradient centrifugation. The five A′–A isozymes are restricted to LDH from trout muscle and migrate very slowly toward the anode. The B′–B subunit series of isozymes are ubiquitous in trout tissues, although cell specific proportions of isozymes occur. While the A′–A subunit genes must be present in all trout cells, they are active only in the muscle where their products are responsible for essentially all of the LDH activity in this tissue.Isozyme patterns reveal that B subunit‐containing tetramers (less anodal) predominate in LDH from liver, whereas B′ subunit molecules (more anodal) prevail in LDH from trout heart. Therefore, extracts from heart, muscle, and liver tissues were utilized to characterize and compare the duplicated subunit tetramers of LDH in terms of several physico‐chemical and physiological parameters.Substrate kinetics show that trout B′ subunit tetramers are very sensitive to increases in pyruvate and lactate. These isozymes attain maximum initial velocity at about 0.8 μmole of pyruvate, while substrate inhibition begins at 7 μmoles. The B and the A′–A tetramers reach maximum initial velocity at 1.3 and 3.5 μmoles of pyruvate, respectively, and inhibition does not begin until substrate concentrations of about 20 μmoles are reached. Results are similar with lactate as substrate. Only the B′ tetramers exhibit substrate inhibition with lactate.An analysis of competitive pyruvate and oxamate inhibition reveals that the LDH active site(s) binds one molecule of inhibitor (or substrate).The inactivating temperature for trout B′ subunit tetramers is 70–75°C; for B subunit tetramers, 65–70°C; and for A′–A tetramers, 46–54°. The A′–A and the B subunit‐containing tetramers possess the generally lower thermal stability characteristic associated with LDH‐5 from most other animals, but thermolability is much more pronounced in the A′–A tetramers. Kinetics of the thermal inactivation process show that it is a first‐order, unimolecular event consistent with protein denaturation.Homologies of trout LDH isozymes with those of higher vertebrates are discussed in relation to these data.
Effects of vitamin A deficiency on the pituitary‐gonad axis of the California quail, Lophortyx californicus
Authors: Fletcher Richard A. 
Published: June 2005

AbstractVitamin A deficiency results in a decrease in number of large basophils (presumed gonadotropes) in male Lophortyx californicus and a decrease in large basophil cell diameters in females. Decrease in functional activity (as judged by number and size) of this cell type may be partially responsible for the observed effects of vitamin A deficiency on reproduction. Gonads of nondeficient birds respond positively to gonadotropins. The testes of vitamin Adeficient birds produce androgens, but spermatogenesis was subnormal. The hormone‐producing component of ovaries of vitamin A‐deficient birds responds to gonadotropins, but follicular development does not occur. Vitamin A deficiency in the California Quail appears to act both at the pituitary (and/or hypothalamic) level and at the gonadal level to result in decreased reproductive competence.
Polar granules of Drosophila. IV. Cytochemical studies showing loss of RNA from polar granules during early stages of embryogenesis
Authors: Mahowald Anthony P. 
Published: June 2005

AbstractPolar granules stain with basic dyes at pH 4.0 in 1 μ plastic sections of mature eggs and of embryos immediately after fertilization. This staining property is removed with hot trichloacetic acid hydrolysis. After the formation of pole cells, polar granules no longer stain at pH 4.0. With the indium trichloride procedure of Watson and Aldridge, polar granules of the mature egg stain with moderate density, and their stainability is removed by cold perchloric acid extraction. Following fertilization, the RNA content of the polar granule rapidly decreases, until, at the blastoderm stage, polar granules do not have more electron density than mitochondria. Both their staining properties and their extractibility with acid indicate that polar granules contain RNA which disappears by the blastoderm stage.