bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternative genetic models for the inheritance of the phenylthiocarbamide taste deficiency
Authors: Olson Jane M. , Boehnke Michael , Neiswanger Katherine , Roche Alex F. , Siervogel Roger M. , MacCluer Jean W.
Published: June 2005

Pedigree segregation analysis was used to examine several one‐ and two‐locus models of the inheritance of phenylthiocarbamide (PTC) taste deficiency that extend the traditional one‐locus recessive model by the addition of either another allele or another locus, and in some cases predict two types of nontasters. These models allow nontaster by nontaster matings to produce taster offspring, consistent with our data and several previous studies which use the Harris and Kalmus [Annals of Eugenics 15:24–32, 1949] dilution method. The models fit our data set of 1,152 individuals from 120 families significantly better than the one‐locus recessive model. The best fit was obtained with a two‐locus model in which one locus controls PTC tasting and the other locus controls a more general taste ability. This model is consistent with research on the physiology of PTC tasting and with results from genetic linkage studies. Further study is suggested to evaluate better the accuracy of the proposed model.
Blood pressure and other cardiovascular disease risk factors in black adults with sickle cell trait or glucose‐6‐phosphate dehydrogenase deficiency
Authors: Nwankwo Martin U. , Bunker Clareann H. , Ukoli Flora A. , Omene Jackson A. , Freeman Donald T. , Vergis Emanuel N. , Yeh Lan Lan , Kuller Lewis H. , Rao D. C.
Published: June 2005

In this study, we examined the relationship of two common genetic markers in black populations, sickle cell trait and glucose‐6‐phosphate dehydrogenase (G‐6‐PD) deficiency, to cardiovascular risk factors. The subjects were Nigerian civil servants in Benin City, Nigeria. We measured blood pressure, height, weight, sickle cell hemoglobin, G‐6‐PD, proteinuria, microalbuminuria and fasting serum cholesterol, high‐density lipoprotein cholesterol (HDL), triglycerides, apoprotein (APO) AI, and APO B. Data were collected on age, alcohol consumption, cigarette smoking, job status, and years lived in an urban area. There were 257 males (3 SS hemoglobin, 73 AS, 181 AA) and 69 females (23 AS, 46 AA). In comparing cardiovascular risk factors, males differed only in percent of smokers (31.5 in AS vs. 17.8 in AA, P < 0.01). Among females, only high‐density lipoprotein (HDL) cholesterol differed (61.5 mg/dl in AS vs. 52.4 in AA, P < 0.01). We hypothesize that females with sickle cell trait are more likely to use oral contraceptives than nontrait females. If so, the high‐estrogen oral contraceptives available in Nigeria could elevate HDL. G‐6‐PD deficiency status among males (52 deficient, 207 nondeficient) and females (1 deficient, 5 carriers, 65 nondeficient) was not related to any of the cardiovascular risk factors. We conclude that sickle cell hemoglobin trait and G‐6‐PD deficiency are not useful genetic markers for risk factors for cardiovascular disease.
Genetic markers associated with high density lipoprotein cholesterol levels in a biracial population sample
Authors: Anderson Richard A. , Burns Trudy L. , Wallace Robert B. , Folsom Aaron R. , Sprafka J. Michael , Vogler G. P.
Published: June 2005

An explanation for the consistently documented finding of higher levels of high density lipoprotein‐cholesterol in black men relative to white men was sought by comparing the frequency of restriction fragment length polymorphism markers present in blacks and in whites at the gene loci coding for the two major apolipoprotein constituents of high density lipoprotein, apolipoproteins AI and AII. The measurements were made in population‐based samples of 45 to 54‐year‐old black (n = 190) and white (n = 370) subjects from the Minnesota Heart Survey for whom lipoprotein levels were available. The mean high density lipoprotein‐cholesterol level for black men in the sample (47 ± 1.5 mg/dl) was higher (P < 0.05) than that for white men (42 ± 0.9 mg/dl), while levels in women were not different between races. While the SacI and MspI markers at the apolipoprotein AI‐CIII‐AIV gene locus showed similar frequencies in blacks compared to whites, the degree of the linkage disequilibrium previously noted between these markers in white subjects was altered in blacks and the minor allele of the PstI marker at this locus was virtually absent in the black subjects (P < 0.005 vs whites). For black men, there were significant associations of the M2 allele and the S2M2 haplotype at the apolipoprotein AI locus with lower high density lipoprotein‐cholesterol levels. The results are consistent with the hypothesis that DNA sequence variations in the vicinity of the apolipoprotein AI‐CIII‐AIV gene locus are associated with the difference in high density lipoprotein‐cholesterol levels between blacks and whites. © 1992 Wiley‐Liss, Inc.
Genetic analysis combining path analysis with regressive models: The beta path model of polygenic and familial environmental transmission
Authors: Li Zhaohai , Bonney George E. , Rao D. C.
Published: June 2005

We have extended the class D regressive model for the purpose of combined path and segregation analyses by incorporating the BETA path model. We have done this by expressing correlations among residuals from major genotype (RMGs) of family members under the class D regressive model as functions of path coefficients under the BETA path model. The likelihood function under the combined model was factorized into a product of conditional densities, which is dominated by bivariate normal densities. Statistical inferences under the combined model are analogous to those under the class D regressive model.
Complexes of thiomandelate and captopril mercaptocarboxylate inhibitors to metallo‐β‐lactamase by polarizable molecular mechanics. Validation on model binding sites by quantum chemistry
Authors: Antony Jens , Piquemal Jean‐Philip , Gresh Nohad
Published: June 2005

Using the polarizable molecular mechanics method SIBFA, we have performed a search for the most stable binding modes of D‐ and L‐thiomandelate to a 104‐residue model of the metallo‐β‐lactamase from B. fragilis, an enzyme involved in the acquired resistance of bacteria to antibiotics. Energy balances taking into account solvation effects computed with a continuum reaction field procedure indicated the D‐isomer to be more stably bound than the L‐one, conform to the experimental result. The most stably bound complex has the S− ligand bridging monodentately the two Zn(II) cations and one carboxylate O− H‐bonded to the Asn193 side chain. We have validated the SIBFA energy results by performing additional SIBFA as well as quantum chemical (QC) calculations on small (88 atoms) model complexes extracted from the 104‐residue complexes, which include the residues involved in inhibitor binding. Computations were done in parallel using uncorrelated (HF) as well as correlated (DFT, LMP2, MP2) computations, and the comparisons extended to corresponding captopril complexes (Antony et al., J Comput Chem 2002, 23, 1281). The magnitudes of the SIBFA intermolecular interaction energies were found to correctly reproduce their QC counterparts and their trends for a total of twenty complexes. © 2005 Wiley Periodicals, Inc. J Comput Chem 11: 1131–1147, 2005
On perfect nonlinear functions
Authors: Xiyong Zhang , Wenbao Han , Shuqin Fan
Published: June 2005

An Erratum has been published for this article in Journal of Combinatorial Designs 14: 82–82, 2006.

We give the equivalence between perfect nonlinear functions and appropriate splitting semi‐regular relative difference sets, construct a class of splitting relative difference sets by using Galois rings and bent functions, and prove that there exists a 4‐phase perfect nonlinear function if and only if the number of input variables is at least twice the number of output variables. © 2005 Wiley Periodicals, Inc.
Preparation of cells cultured on silicon wafers for mass spectrometry analysis
Authors: Wittig Andrea , Wiemann Martin , Fartmann Michael , Kriegeskotte Christian , Arlinghaus Heinrich F. , Zierold Karl , Sauerwein Wolfgang
Published: June 2005

The distribution of specific atoms and molecules within living cells is of high interest in bio‐medical research. Laser secondary neutral mass spectrometry (laser‐SNMS) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) detect atoms with high sensitivity and spatial resolution. The application of these methods to cultured cells requires special preparation techniques preserving morphological and chemical integrity of the living cells. The cells should, therefore, be grown on a conducting material preventing charging of the sample during ion bombardment. Silicon is currently used as the preferred support material for non‐biological samples in mass spectrometry. This study investigates (1) the influence of silicon surfaces on cell growth and (2) the suitability of a sandwiched, rapid freezing method to analyse transmembrane ion gradients. Human melanoma cells were grown on silicon with polished or etched surfaces. Growth kinetics were studied using the Sulforhodamine‐B assay. Number, shape, and morphology of the cells were assessed by epifluorescence microscopy of calcein AM‐ and DAPI‐stained cells. Cells were subjected to rapid freezing, freeze‐fracturing, and freeze‐drying prior to analysis by TOF‐SIMS and laser‐SNMS. While cell numbers and morphology on the rough silicon wafers were impaired, morphology and growth kinetics of cells on polished silicon were identical to control cells on cell culture tested polystyrene. TOF‐SIMS and laser‐SNMS resulted in high‐resolution elemental images and mass spectra. Measurement of the intracellular Na+ and K+ concentrations revealed a ratio as observed in living cells. In conclusion, culturing cells on polished silicon wafers followed by sandwiched, rapid freezing is an adequate preparation method to study intracellular ion distribution with mass spectrometry. Microsc. Res. Tech. 66:248–258, 2005. © 2005 Wiley‐Liss, Inc.
Elemental changes in the brain, muscle, and gut cells of the housefly, Musca domestica, exposed to heavy metals
Authors: Tylko Grzegorz , Banach Zuzanna , Borowska Joanna , Niklińska Maria , Pyza Elżbieta
Published: June 2005

The toxic effects of heavy metals on organisms are well established. However, their specific action at the cellular level in different tissues is mostly unknown. We have used the housefly, Musca domestica, as a model organism to study the toxicity of four heavy metals: copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb). These have been fed to larvae at low and high, semi‐lethal concentrations, and their accumulation in the head, thorax, and abdomen was subsequently measured in adult flies. In addition, their impact on the cellular concentration of several elements important for cell metabolism—sodium (Na+), magnesium (Mg++), phosphorous (P), sulphur (S), chloride (Cl−) and potassium (K+)—were measured in neural cells, muscle fibers, and midgut epithelial cells. Our study showed that the heavy metals accumulate mainly in the abdomen, in which the concentrations of two of the xenobiotic metals, Cd and Pb, were 213 and 23 times more concentrated, respectively, than in controls. All the heavy metals affected the cellular concentration of light elements in all cell types, but the changes observed were dependent on tissue type and were specific for each heavy metal, and its concentration. Microsc. Res. Tech. 66:239–247, 2005. © 2005 Wiley‐Liss, Inc.
Cadmium distribution and effects on ultrastructureand chlorophyll status in photobionts and mycobionts of Xanthoria parietina
Authors: Sanità Di Toppi Luigi , Musetti Rita , Vattuone Zulema , Pawlik‐Skowrońska Barbara , Fossati Fabrizia , Bertoli Lorenzo , Badiani Maurizio , Favali Maria Augusta
Published: June 2005

In this work, we tried to go deeper inside distribution and toxicity of cadmium (Cd) in the macrolichen Xanthoria parietina (L.) Th. Fr. Thalli of this species were treated with 0 (control), 4.5, 9, 18, or 36 μM Cd for 24 or 48 hours. Transmission electron microscopy, X‐ray microanalysis, and electron energy loss spectroscopy were exploited to study distribution and ultrastructural effects of Cd in thalli; spectrophotometric techniques were utilized for measuring Cd effects on chlorophyll (Chl) content; light fluorescence microscopy was used to evaluate Chl autofluorescence. The highest Cd concentration caused ultrastructural alterations both in the mycobiont and in the photobiont, more severe in the latter, decreased total Chl content and progressively quenched Chl autofluorescence. Cell wall immobilization was observed in both bionts, and evidence pointing to a Cd‐binding ability by the concentric bodies in the mycobiont was also obtained. Lower Cd concentrations led to slight or even no effects on thallus structures and on Chl content and autofluorescence. The results obtained suggest that: (1) among the two bionts, the algal partner appears to be more susceptible to Cd stress, probably because of the presence of delicate and sensitive components such as the chloroplast and photosynthetic pigments; (2) a concentration threshold exists for the occurrence of evident structural and functional damage in X. parietina thalli exposed to Cd. Microsc. Res. Tech. 66:229–238, 2005. © 2005 Wiley‐Liss, Inc.
The revolution of counting “tops”: Two decades of the disector principle in morphological research
Authors: Geuna Stefano
Published: June 2005

Twenty years have passed since the publication of the seminal paper enunciating the disector principle by an author using the pseudonym D.C. Sterio. During this time, methods based on the revolutionary principle of counting “tops” have become progressively better known and have been included in several commercially available systems for quantitative morphology. Analysis of the number of published studies citing Sterio's paper on the ISI Web of Knowledge® database showed that its scientific “impact factor” has almost continuously risen since its publication, indicating the growing knowledge about disector‐based methods in the various scientific fields where morphological quantification is required. This report briefly reviews the first two decades of disector use, pointing to its advantages as well as to shortcomings that have recently been addressed in critical papers and have given rise to a lively debate on the role of counting tops in quantitative morphology today. Microsc. Res. Tech. 66:270–274, 2005. © 2005 Wiley‐Liss, Inc.
The fate of sperm middle‐piece mitochondria in the rat egg
Authors: Szollosi Daniel
Published: June 2005

Mitochondria 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

The 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

Nine 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

Ciliates 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

Trunk 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

Two 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

The 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

An 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

Diploid 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

In 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

The 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

The 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

Female 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

Liver 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

Peptide 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

Vitamin 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

Polar 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.
Nervous system transplantation in hydra
Authors: Saffitz Jeffrey E. , Burnett Allison L. , Lesh Georgia E.
Published: June 2005

Cnidarians are the most primitive metazoans possessing a nervous system. The hydroid nervous system consists of single sensory, neurosecretory and ganglionic cells concentrated at the extremities of the animal. Present evidence suggests that nerve tissue arises from the differentiation of interstitial cells.

Exposure of hydra to nitrogen mustard (methyl bis (beta‐chloro ethyl) amine hydrochloride) causes the selective elimination of interstitial cells (Diehl and Burnett, '64). Cells which normally arise from interstitial cell differentiation subsequently become depleted. Distoproximal grafts between normal hydra and nitrogen mustard treated animals of a different species result in interstitial cell migration across the graft junction. Autoradiographic evidence demonstrates that the host hydra accepts the donor's interstitial cells which proliferate and differentiate into nerve tissue and functional cnidocytes.

Although newly established cnidocyte populations are normal in seven day old grafts, nerve and interstitial cell populations are reduced. Furthermore, there is an abnormal apico‐basal distribution of interstitial cells in these grafts.

A comparison of “nervous system transplant” animals with those treated with nitrogen mustard for a similar time period but not grafted suggests that the transplanted nervous system is functional. The ultimate death of experimental animals supports speculation that nitrogen mustard causes irrevocable gastrodermal damage.

Various parameters germane to the function of the nervous system in hydra are being established, including developmental, behavioral and electrophysiological correlates. Once nervous system transplant chimeras are reared in sufficient numbers, a comparison of these with host and donor species should provide insight into the functional nature of hydra's nervous system.
Marsupial and monotreme lactate dehydrogenase isozymes: Phylogeny, ontogeny, and homology eutherian mammals
Authors: Holmes Roger S. , Cooper Desmond W. , Vandeberg John L.
Published: June 2005

Lactate dehydrogenase (LDH) isozymes have been examined from tissues of mammalian species representative of the five families of marsupials and of the monotremes. Immunochemical, molecular hybridization, and tissue distribution studies showed that three genes (A, B and C) are responsible for LDH synthesis giving rise to five major isozymes in most tissues (LDH's A4, A3B1, A2B2, A1B3, and B4) and an additional isozyme (LDH‐C4) which is present only in mature testes. The LDH phenotypes of 93 erythrocyte samples from 31 marsupial and 2 monotreme species were analysed. Although the isozymic composition varied markedly within the marsupial families Macropodidae and Phalangeridae, the Dasyuridae showed remarkable uniformity, containing only LDH‐A4. The two monotreme species analysed also exhibited this latter pheno‐type in their erythrocytes. Ontogenic studies of the LDH isozymes of pouch young from Macropus parryi (pretty‐face wallaby) showed changes similar to those reported for the developing mammalian fetus in utero. The immature pouch young exhibited similar tissue patterns of LDH isozymes which diverged during growth in the pouch thus reflecting differential genetic activity. A comparison of the relative maturity of the eutherian fetus with marsupial pouch young may be made. From these observations, it is concluded that a high degree of correlation exists among the properties of eutherian, marsupial, and monotreme LDH isozymes.
An enzymatic comparison of sea urchin egg ghosts prepared before and after fertilization
Authors: Barber Mary Lee , Foy James E.
Published: June 2005

Ghosts were prepared from sea urchin eggs, before and after fertilization. Eggs were treated with Mg++ to stabilize the surface. Cytoplasm was then released by osmotically lysing the cells and washing repeatedly at low ionic strength. Microscopically, the resultant ghosts appear to contain the extraneous surface coats, some cell cortex, and the plasma membrane, but relatively little cytoplasm. This appearance and the higher specific activities of Na+‐K+‐ATPase, Mg++‐ATPase, and acetylcholinesterase in ghosts than in whole egg homogenates, indicates the usefulness of ghost preparations as egg surfaces in enzyme comparison studies. The specific activities of five of the six enzymes measured are different when compared in ghosts prepared before and after fertilization. Glucose‐6‐phosphate‐dehydrogenase, acetylcholinesterase, and Na+‐K+‐ATPase activities are greater in fertilized than in unfertilized egg ghosts, whereas the Mg++‐ATPase and glucose‐6‐phosphatase activities are lower. The changes in enzyme specific activities following fertilization may be related to structural and functional changes which occur in the egg surface at that time.
Opercular regulation in the polychaete Hydroides dianthus (verrill, 1873) II Control of opercular regulation
Authors: Schochet Joy
Published: June 2005

When the adult functional operculum of the serpulid polychaete Hydroides dianthus is amputated at any level below the secondary cup, the rudimentary operculum develops into a functional one. Concomitantly a new rudimentary operculum regenerates from the stump of the former functional operculum. This reversal of asymmetry is proportional to the degree of injury (e.g., amputation > crushing > ligation > puncture). Amputating the rudimentary operculum does not affect the functional one, but in some cases the regenerating rudimentary operculum may differentiate into a second functional operculum. When distal portions of both opercula are removed, reversal occurs, and if the two opercula are amputated simultaneously at the base, a functional operculum regenerates on the side opposite its original position. If, however, the branchial apparatus is amputated together with both the functional and rudimentary opercula, the latter tends to regenerate on the original side. Thus the opercular regulatory system distinguishes between degrees and types of injury to the functional operculum, and the branchiae may be involved in opercular relationships.

If the animal is decerebrated or the supraoesophageal ganglion is bisected, the opercula are still able to reverse normally. No reversal occurs when the external opercular nerves are severed, but in about one‐third of the animals reversal occurred after section of the internal nerve. No direct nervous connection is involved in opercular communications, but the internal opercular nerve is implicated in stimulating reversal.
Cell division and ribonucleic acid synthesis during the initiation of limb regeneration in larval axolotls (Ambystoma mexicanum)
Authors: Kelly Daryl J. , Tassava Roy A.
Published: June 2005

Mitotic activity and RNA synthesis were examined in normal regenerating limbs and denervated non‐regenerating limbs of larval axolotls during the first six days after amputation. H3‐uridine incorporation into RNA was measured by autoradiography of deoxyribonuclease treated sections. Grain counts indicated a significant increase in RNA synthesis in both normal and denervated limbs through the six‐day time period but a greater increase was seen in normal limbs.

The Mitotic Index increased significantly in normal limbs on the fifth day postamputation. In contrast, no increase in M.I. was observed in denervated limbs.
Ultrastructure of the mesoglea in strobilae of Chrysaora quinquecirrha (scyphozoa)
Authors: Bynum Mary A. , Black R. E.
Published: June 2005

Large numbers of mesogleal fibers are found in constricted regions of Chrysaora strobilae. The mesoglea in these regions appears to be branched. Many fibers are oriented normal to the surfaces of gastrodermal cells. The mesoglea of non‐constricting regions contains similar fibers, most of which are not so oriented. Fibers and fiber bundles in the constricting regions may serve as a barrier to vertical cell migration, so that formation of ephyrae can occur. The fibers may also serve to stabilize constrictions once they are formed. Microfilament bundles, oriented transversely to the oral‐aboral axis, are present in the gastrodermis of scyphistomae.
Electron microscopic studies of planarian regeneration. II. Changes in epidermis during regeneration
Authors: Morita Michio , Best Jay Boyd
Published: June 2005

Histological changes in planarian epidermis, as well as the differentiation of new epidermal cells during the course of differentiation, were studied with the electron microscope.

Immediately after decapitation, pre‐existing epidermal cells of the area surrounding would stretch out over the cut‐surface and cover it completely with a thin film within 16 hours. However, these epidermal cells in the film were replaced by newly differentiated cells during the period extending from the second to sixth day of regeneration. Thus, after injury, the initial compensational closure is formed on the cut‐surface by the pre‐existing epidermal film, but the epidermis which is finally regenerated is formed by complete colonization of pre‐existing epidermis by newly differentiated epidermal cells. New epidermal and rhabdite‐forming cells were found not only in epidermis but also in the interior and sub‐epidermal regions of the blastema and in the old tissue close to the wound surface. Our observations suggest that ectodermally oriented cells, such as epidermal and rhabdite‐forming cells, originate from neoblasts at the anterior of the old body, close to its interface with the regeneration blastema; such neoblasts differentiate into rhabdite‐forming, or epidermal, cells as they migrate from the old somatic stump through the regeneration blastema into its epidermal surface layer. The characteristic polarity of epidermal cells appears in newly differentiated ones when they locate in the epidermal surface.