bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental studies on hatching behavior in the chick. II. Extirpation of the right wing
Authors: Narayanan C. H. , Oppenheim Ronald 
Published: June 2005

AbstractThe right wing of chick embryos, stages 17–18, was extirpated with a view to study the effect of the absence of the right wing on prehatching motility and hatching behavior. Half of the embryos which survived, hatched normally. Detailed observations on these embryos showed that they followed the typical sequence of behaviorial events from day 17 until hatching. The types of behavior patterns were strikingly similar to embryos with both wings intact. A comparison of the qualitative aspects of prehatching behavior showed an increase of head movements in embryos without the right wing.
Effect of castration on muscle growth in the mouse
Authors: Rowe R. W. D. 
Published: June 2005

AbstractMale 129/Re mice were castrated at 18–24 days of age. At 20 weeks of age they were sacrificed and the body weights and the weights of the anterior tibialis, biceps brachii, extensor digitorum longus, soleus and sternomastoideus were recorded. These muscles were also examined cytologically for total fiber number and fiber diameter distributions. The differences between the muscle weights of castrates and controls were correlated with different levels of fiber growth. The level of fiber growth in the phasic anterior tibialis, biceps brachii and extensor digitorum longus (i.e. muscles bringing about body movements) was concluded as being under the indirect control of the pituitary growth hormone, in that it acts on the body as a whole thereby increasing the work load of these muscles. Whereas for the sternomastoideus there appears to be a more direct effect of testosterone.
Acetylcholinesterase and choline acetyltransferase activity in the developing chick spinal cord
Authors: Burt Alvin M. 
Published: June 2005

AbstractMicrochemical procedures were employed for the quantitative assay of acetylcholinesterase (AChE) and choline acetyltransferase (ChAc) activity in the brachial spinal cord of chick embryos from 3.5 to 21 days' incubation. The activity of AChE increased nearly 10‐fold during the 60‐hour period from stage 22 (3.5 days) to stage 30 (6.0 days). The level of AChE at six days was essentially the same as that at hatching. During the intervening period, the level of AChE activity remained unchanged with the exception of minor transient peaks at days 7, 13, and 18. The activity of ChAc increased 22‐fold during the developmental period studied. The onto‐genetic pattern was characterized by two periods of rapid increase in acitvity. From stage 23 (3.75 days) to stage 31 (7.0 days), ChAc activity increased approximately 5.4‐fold and from stage 38+ (12.5 days) to stage 44, (18 days) ChAc activity increased approximately 3.6‐fold with the major increase occurring during the 48‐hour period from stage 42 to stage 44. The ontogenetic patterns for both enzymes are discussed in relation to morphological and functional differentiation. It is suggested that ChAc activity is a more reliable index of functional differentiation than is AChE and that the initial increase in AChE activity may be associated with some function other than synaptic transmission.
Temporal pattern of macromolecular events during the microstome‐macrostome cell transformation of Tetrahymena vorax strain V2S
Authors: Buhse Howard E. , Cameron Ivan L. 
Published: June 2005

AbstractDifferentiation of cell type can be experimentally controlled in the ciliated protozoan Tetrahymena vorax. If an early stationary growth phase population of small‐mouthed saprozoic cells (called microstomes) is washed and suspended in a transforming principle, stomatin, (which is released by a potential prey, i.e., Tetrahymena pyriformis), the microstomes transform into a population of large‐mouthed potentially carnivorous cells (called macrostomes). This process is observed by four and one‐half hours after stomatin addition. During cell transformation the pattern of DNA, RNA and protein synthesis were measured by autoradiographic and chemical techniques.Microstomes undergo macrostome formation with a net synthesis of cellular protein and RNA. Autoradiographs demonstrate that no new cells enter DNA synthesis during the first four hours of cell transformation. Isotope labeling and chemical data demonstrate that RNA synthesis is stimulated by stomatin and reaches a peak at about 150 minutes; increased protein synthesis lags somewhat behind RNA synthesis and does not reach a peak until 210 minutes. The increased synthesis of RNA and protein is associated with disaggragation of fused nucleoli into individual nucleoli. The disaggregation of fused nucleoli and the associated increases in RNA and protein synthesis appear necessary for the ensuing morphogenetic events which lead to macrostome formation. Apparently stomatin is serving as a relatively rich source of nutrient.
The influence of neural tissue on the early development of somitic muscle in ventrolateral implants in Ambystoma
Authors: Muchmore William B. 
Published: June 2005

AbstractProspective somite mesoderm from both sides of an Ambystoma neurula was implanted under the flank ectoderm of another embryo at stage 20–22. The host was fixed and studied after a period ranging from ten days to three months. After ten days to two weeks of culture there was good differentiation of muscle in the implants, just as in explants of the same amount of presumptive somite mesoderm into an ectodermal jacket. Subsequent to this, the muscle cells which had differentiated began to degenerate, and after a month or more only a trace of muscle, or none at all, was found. When presumptive spinal cord was included with such implants, initial differentiation of muscle was similar histologically and quantitatively, but the muscle cells were better organized into myotomes than in the first experiment. In these cases, also, the quantity of muscle in the graft tended to decrease after two weeks, but then increased again by two or three months. The results are interpreted as indicating that the developing spinal cord has little effect on the initial differentiation of muscle cells, but then, after about ten days, the outgrowing nerves exert an important influence on the maintenance and further growth of the myotome.
Effect of thyroxin on the gonad and body weight of Spotted Munia, Uroloncha punctulata
Authors: Thapliyal J. P. , Garg R. K. , Pandha S. K. 
Published: June 2005

AbstractLow doses of l‐thyroxin promote feather regeneration and lead to significant reduction in the mean weight of the gonad of adult normal and thyroidectomized Spotted Munia, Uroloncha punctulata, in the breeding phase. At moderately high doses of thyroxin complete molting occurs, and the mean weight of the gonoduct is also significantly reduced. The effect of l‐thyroxin increases as the duration of administration is increased. There is practically no difference between the response of normal and thyroidless birds.It is suggested that whereas the effects of l‐thyroxin on the plumage are by way of body metabolism, those on the gonad, gonoduct and body weight are due to a direct influence on the output of the gonad‐stimulating and growth‐promoting hormones from the adenohypophysis.
Subsequent development during incubation of fertilized mouse ova stressed by high ambient temperatures
Authors: Elliott D. S. , Burfening P. J. , Ulberg L. C. 
Published: June 2005

AbstractMouse embryos subjected to high temperature stress (heat‐stress) in vivo during the time of first cleavage division, were recovered from the oviducts 48 to 54 hours post‐observance of a copulatory plug. The effects of heat‐stress on development of those embryos incubated in vitro through the blastocyst stage were studied and compared to embryos from mice in a control environment. Heat‐stressed embryos which developed in vivo to ten days gestation were also studied.Development of heat‐stressed embryos was retarded by the time of recovery. There was a significant (P<0.05) decrease in the number of heat‐stressed embryos which became blastocysts in vitro, as compared to control embryos. Also, there were fewer blastocysts from heat‐stressed embryos which hatched during three days of incubation in vitro when compared to controls (56% vs 67% for heat‐stressed and controls, respectively). There was significant (P<0.01) pre‐ and post‐implantation loss of embryos in heat‐stressed females at ten days gestation.
Gross morphology and predictability for survival of 4‐day rabbit embryos following heat‐stress during the first cleavage division
Authors: Burfening P. J. , Alliston C. W. , Ulberg L. C. 
Published: June 2005

AbstractRabbit embryos were subjected to heat‐stress during the first cleavage division. Those embryos to be heat‐stressed in vitro were recovered at 19 hours after mating and incubated at either 38° or 40°C for six hours, then returned to the original doe. Others were heat‐stressed in vivo by subjecting the doe to a temperature of either 21° or 32°C for 28 hours beginning four hours before mating. Four days after mating embryos were recovered and scored for normality. Those which appeared to be normal were deposited into one uterine horn and the others were deposited into the opposite horn of a synchronous pseudopregnant recipient. Numbers of implantation sites and living fetuses were determined twelve days after mating.There was a significant (P < 0.01) reduction in the proportion of ova which cleaved in vitro but no difference due to incubation temperature. Four days after mating significantly (P < 0.01) fewer of the embryos exposed to the higher temperature were classified as normal (49% and 45% vs 87% and 74% for ova stressed in vivo or in vitro, respectively). Of the embryos classified normal, 96% and 91% implanted in the 21° and 32°C group, respectively. But 50% of the abnormal embryos also formed implant sites in the 32°C group, however, only 12% of these sites contained a viable fetus. The proportion of embryos forming implantation sites or viable fetuses depended upon the amount of stress that the embryo had been subjected to early in its development. Morphology of a 4‐day old embryo is not indicative of its ability for subsequent survival.
Cell lineage of the imaginal discs in Drosophila gynandromorphs
Authors: Garcia‐Bellido A. , Merriam J. R. 
Published: June 2005

AbstractA collection of 379 drawings of D. simulans claret gynandromorphs, kindly supplied to the authors by Dr. A. H. Sturtevant, was used in order to analyze the cell lineage of the adult cuticular structures. The marker phenotypes forked bristles or yellow body color were used to trace the male tissue. The degree of mosaicism within the different imaginal discs was used to estimate the number of blastoderm nuclei whose descendants form the primitive imaginal discs on each side. The estimates are 23 for the compound‐eye‐antennal discs, 12 for the wing disc, several for the first and second leg discs and perhaps 1 for each of the prothoracic, third leg and abdominal discs. The frequency with which two parts are separated by sex, one male and one female, is assumed to vary inversely with the closeness of their embryonic descent. In this way were constructed the morphogenetic maps of the relative locations on one side of the embryo of the presumptive head, thoracic and abdominal adult structures. Locations of the presumptive parts within the morphogenetic maps are the same as the relative positions of the parts on the adult surface. Arguments are presented to place the morphogenetic map on the three‐dimensional surface of the egg. The data are consistent with the model that the morphogenetic map of the prospective adult structures occupies a medial band along both sides of the embryo surface. Poulson's ('50) ground plan of the egg also places the presumptive larval hypodermis in this location. This model is considered relative to the experimental evidence marking the early embryo stages.
Effects of cold exposure and hibernation on the liver, brown fat, and testes from golden hamsters
Authors: Frehn John L. , Thomas Joseph A. 
Published: June 2005

AbstractAdult, male hamsters, (Mesocricetus auratus, Waterhouse), were exposed to an environment of 5 C (2 months and 3 to 4 months) to investigate the effects of cold‐exposure and 2 to 5 days of hibernation on the following parameters: (1) body weights, (2) testes weights, (3) testes and brown fat histology and histochemistry, and (4) liver and brown fat mitochondrial succinate oxidation. Controls were maintained at room temperature. Only the hibernating animals lost a significant amount of weight during exposure. Although the testes regressed in both cold‐exposed and hibernating animals, the testes of hibernators showed some signs of recrudescence relative to the cold‐exposed non‐hibernators, as indicated by increased spermatogenic activity, slightly larger seminiferous tubules, greater organ weights, and the presence of PAS positive, diastase sensitive material. Brown fat in experimental animals had smaller and more numerous fat droplets per cell than the controls and nuclei which appeared to be more centrally located. Analysis of liver mitochondrial activity revealed the rate of succinate oxidation to be reduced in hibernators and increased in cold‐exposed non‐hibernators. Brown fat succinate oxidation was unaltered in both experimental groups. These results indicate that, early in the hibernation cycle, both physiological and morphological changes occur which distinguish hibernating hamsters from cold‐exposed hamsters which failed to hibernate.
Insect neurometamorphosis. IV. Effects of the brain and synthetic α‐ecdysone upon interganglionic connective shortening in Galleria mellonella (L.) (Lepidoptera)
Authors: Pipa Rudolph L. 
Published: June 2005

AbstractThe interganglionic connectives of pharate pupae and pupae < 5 hours after ecdysis (early pupae) of Galleria mellonella will cease shortening if the segments in which they lie are separated from the prothorax. Though shortening is not prevented by removing the brain of an early pupa, it will be delayed several days. This period is prolonged to more than a week if the corpora cardiaca (Cc) and corpora allata (Ca) are removed together with the brain. The retardation induced by extirpating all three organs is prevented by implanting a single brain from a pupa or an adult, but not by implanting ganglia. It is also alleviated, to a lesser extent, by one or two pairs of Cc‐Ca.As many as three brains transplanted into a posterior pupal fragment deviod of acknowledged endocrines will not initiate shortening, but implanting a single brain into a decerebrated anterior fragment will. The evidence suggests that the brain does not regulate shortening directly. Instead, it may do so by producing prothoracotropic hormone.Approximately 0.03 μg of synthetic α‐ecdysone per animal is sufficient to cause 50% of the meso‐metathoracic connectives of brainless pupae to shorten half their initial length or more within three days. For posterior pupal fragments, however, ca. 0.06 μg per animal is required. The sensitivity of this developing system to ecdysone parallels its responsiveness to transplanted brains, and the shortening nerve cord may be useful in assaying for brain hormone.
Latency relationships between loosely coordinated locust flight motor neurons
Authors: Waldron Ingrid , Wilson Donald M. 
Published: June 2005

AbstractDuring flight the pattern of activity of the motor neurons of the locust wing muscles is normally a precisely controlled score. The elevator motor neurons are active in short synchronous impulse bursts and these alternate with similar bursts in the depressor motor neurons. In experimental preparations the normal coordination may break down, so that electrical stimulation of the nerve cord may elicit a very poorly coordinated response. In these cases, a histogram of the relative latencies of activity in two synergistic elevator motor neurons typically shows three modes, indicating that relative latency tends to assume values near 0 msec, about 6–8 msec, and about 25–35 msec. Simultaneous responses to common input play a major role in causing the peak at 0 msec. Excitatory synaptic interactions between motor neurons, or interneurons which drive them, appear to be responsible for the peak at 6–8 msec. The longest latency peak may be due to firing upon recovery from long‐term inhibitory interactions between the synergistic motor neurons. The short‐term excitatory feedback interactions between synergistic motor neurons probably are important for the production of the multiple firing in the impulse burst during flight. Long‐term inhibitory interactions may limit the activity in this positive feedback system and play a role in terminating each burst.
Altered contact behavior of presumptive mesodermal cells from hybrid amphibian embryos arrested at gastrulation
Authors: Johnson Kurt E. 
Published: June 2005

AbstractContact behavior of presumptive mesodermal cells taken from normal amphibian embryos, hybrid embryos, and hybrid embryos arrested at gastrulation was investigated. Normal cells have a high ability to flatten on a glass substratum and reaggregate. Cells from a viable hybrid which shows some abnormalities in invagination have an intermediate ability to flatten on a glass substratum and an undiminished ability to reaggregate. Cells from three different types of hybrid embryos arrested at gastrulation have a low ability to flatten on a glass substratum and reaggregate. The implications of these results for hypotheses concerning mechanisms of morphogenetic cell movements are discussed.
Skin allograft and xenograft rejection in the snapping turtle, Chelydra serpentina
Authors: Borysenko M. 
Published: June 2005

AbstractThe immune response of the snapping turtle, Chelydra serpentina, to skin allografts and xenografts at several environmental temperatures was studied. Xenografts were supplied by the painted turtle, Chrysemys picta, and the Blanding turtle, Emys blandingii. Gross and microscopic manifestations of rejection were observed. Beginning of graft death and total graft death marked two survival end points. The first of these events was used in statistical comparisons of mean survival times of grafts of the various series, which included a total of 107 host animals involving 74 allografts and 76 xenografts.Skin autografts survived through the periods of observation with no morphological evidence of incompatibility. Using gross and histological survival end points, which indicated the beginning of graft death, first‐set allografts were rejected in about 40 days; second‐set in about 21 days, at 25 ± 1°C. Allografts from young snappers survived slightly longer.Xenografts from both donor species were rejected after nearly the same survival times. First‐set xenografts were rejected in about 24 days; second‐set xenografts in about 16 days, at 25 ± 1°C. Painted turtle skin xenografts on snappers which had previously received painted turtle tissue in transplantation between embryos, survived significantly longer, about 36 days.There was no morphological evidence of rejection of first‐set allografts of xenografts for the observation period of 100 days, at 10 ± 1°C. Allografted snappers that were transferred to 25 ± 1°C, rejected the grafts about 30 days after the transfer.First‐set allografts were rejected much faster at 33 ± 1°C, in about 24 days, as were first‐set xenografts, in about 17 days.
The maturation of the capacity to reject skin allografts and xenografts in the snapping turtle, Chelydra serpentina
Authors: Borysenko M. 
Published: June 2005

AbstractSkin allografts and Blanding skin xenografts were transplanted to young snapping turtles ranging in age from newly‐hatched to six months. In this study, involving 88 skin allografts and xenografts, it was shown that the snapping turtle matures immunologically in its capacity to reject grafts several months after hatching. It takes newly‐hatched turtles over 90 days to reject skin allografts and xenografts. The survival times are nearly half that when the animals are only one month of age. Mean survival times then drop a few days with each month of age. By four to six months, snapping turtles reject skin allografts and xenografts at about the same rate as do adult snappers. Skin xenografts were rejected faster than allografts at every age after the newly‐hatched series. There were some cases of very extended sibling skin allograft survival during the early months posthatching. A later series involving older animals showed that sibling allografts were rejected at nearly the same rate as non‐sibling allografts.
Electroencephalographic episodes of 1 to 7 per second rhythmic waves following hypothermic hypoxia in developing chicks
Authors: Peters Joseph J. , Vonderahe Alphonse R. , Hilgeford Eric J. 
Published: June 2005

AbstractDeveloping chicks between the day of hatching and three weeks after hatching were subjected to hypothermia of 20°C followed by nitrogenous hypoxia until breathing ceased and the cerebral electroencephalogram was reduced to zero potential. Resuscitation was started 15 minutes later; 86% of the chicks resumed spontaneous breathing. Eighty percent of the resuscitated chicks showed electroencephalographic episodes usually lasting 1 to 3 minutes and consisting of conspicuously rhythmic blunt spike‐like waves of large amplitude and complex patterns with frequencies in the range of 1 to 7 waves per second until the episode was terminated at almost zero potential. Monopolar techique using the comb as the reference electrode indicated that the EEG episodes were either predominantly bilateral or unilateral, with both gradual and abrupt changes in amplitude, frequency, and site of origin. During episodes the chicks were either motionless or showed tremors of eyelids, limbs, trunk, with occasional staring and chirping. During progressive recovery, as episodes approached, large amplitude waves increased in amplitude and frequency, and changed from domes to blunt spikes. Similar slow waves apeared during episodes and continued during recovery eventually culminating in normal EEG patterns of sleep. Statistically the younger chicks showed briefer and fewer episodes, with the lowest maximum frequency. On the day following experimentation 86% of the resuscitated chicks were alive and showed normal EEG patterns and behavior: death was not limited to chicks having episodes.
The functional development of the reticulo‐endothelial system in the toad, Xenopus laevis (Daudin)
Authors: Turner Rodney J. 
Published: June 2005

AbstractThe development and extent of the phagocytic system in larval and adult Xenopus was determined by injections of colloidal carbon by various routes, followed by dissection and/or histological examination. It was shown that in young tadpoles of stage 48 (aged 7.5 days at 23°C), the small population of pericardial and peritoneal macrophages alone was responsible for phagocytosing intraperitoneally injected carbon. In later stages this population of macrophages in greatly increased, and the tubule cells of the pronephros and mesonephros are capable of ingesting both carbon and mammalian erythrocytes drained from the body cavity. Attention was drawn to a possible relationship between this localization of foreign material in the open kidney, and the lymphoid accumulations found there in Xenopus and other lower vertebrates.Blood‐ and lymph‐borne particles were removed mainly by cells of the spleen and liver in both tadpoles and adults: no phagocytic organs which could be described as lymph nodes were found at any stage. The findings suggest that the reticulo‐endothelial system of Xenopus is more primitive than that of Rana or Bufo.