摘要:

AbstractMaximum efficiency of removal of inhaled ammonia by respiratory mucous in three species of mammals has been determined by noting the increase above normal in plasma ammonia and urea nitrogen after exposing the bloodin vivoandin vitrohightly ammoniated air. Guano bats,Tadarida brasiliensis, filtered 97.1% of the ammonia present in an inhaled mixture of 1130 PPM (parts per million ammonia). These bats further filtered 73.4% of a 4420 PPM in air mixture, 72.6% at 5040 PPM and 53.9% and 7200 PPM. For little brown bats,Myotis lucifugus, filtering efficiencies of 84.5% at 1330 PPM and 77.5% at 3010 PPM were found. Mice,Mus musculus, were found to filter 76.9% at 870 PPM. Efficiency of respiratory ammonia filtration relates directly to tolerance to inhaled ammonia in these mammals.Sodium, potassium, chloride, carbon dioxide, ammonia and urea nitrogen and protein levels in perfused respiratory tract fluid of the same three species after inhalation of ammonia in air mixtures are reported. In each species, ammonia and urea nitrogen levels in perfused respiratory tract fluid increases as inhaled concentrations of ammonia increase. In guano bats and little brown bats, carbon dioxide levels paralleled increases in ammonia apparently in sufficient quantity to provide the increase in buffering capacity necessary to neutralize absorbed ammonia. In mice, however, carbon dioxide levels dropped as inhaled ammonia levels increased. In no case did electrolyte or protein content change in any way to increase buffering capacity of respiratory mucous except in guano bats where protein levels rise consistently with inhaled ammonia concentrations.

ISSN:0022-104X    

DOI:10.1002/jez.1401700302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractTissue engaged in the transformation of iris into lens, triggered by lens removal in the adult newt (Triturus viridescens), was labeledin vitrowith14C‐uridine, and the sedimentation profiles of RNA synthesized by the tissue were studied in sucrose density gradients. The radioactivity in the 18S and 28S areas, which is insignificant in the normal iris, increases significantly during 2 to 10 days after lens removal, and subsequently retains a high level until the completion of lens regeneration. These data are interpreted as indicating activation of ribosomal RNA (rRNA) synthesis by lens removal, and are discussed in connection with the ultrastructural modification of the nucleoli. Further data from the radioactive profiles are consistent with the notion that the level of control of rRNA production in this system is the transcription of the rRNA precursor rather than the post‐transcriptional processing of the precursor. The activation of rRNA production described in this paper is the earliest event so far detected in this system, preceding activation of DNA replication, cell replication, and dedifferentiat

ISSN:0022-104X    

DOI:10.1002/jez.1401700303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractUnheated bovine follicular fluid is very toxic to hamster spermatozoa. This toxicity is due to the action of globulin or globulin‐like substances in the fluid. When the fluid is pre‐treated at 56°C for about 30 minutes these spermicidal substances are detoxified, and the fluid becomes capable of inducing the acrosome reaction and capacitation of the spermatozoa. Follicular fluid contains two factors responsible for the induction of the acrosome reaction and capacitation of spermatozoa, namely the sperm‐stimulating factor and the acrosome reaction‐inducing factor. An efficient sperm acrosome reaction and capacitation can be accomplished only in the presence of these two factors. The sperm‐stimulating factor is dialyzable and heat‐stable (at 90°C). The acrosome reaction‐inducing factor, on the contrary, is non‐dialyzable and heat‐labile (at 90°C). The relationship between sperm acrosome reaction and capc

ISSN:0022-104X    

DOI:10.1002/jez.1401700304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe left colleterial gland, as part of the accessory sex glands of the adult female cockroach, produces a structural protein and the phenolic tanning agent, protocatechuic acid glucoside. Both are needed for the formation of the egg capsule (ootheca), which contains the eggs of the species. The synthesis of the two compounds is under the control of the corpus allatum hormone. Transplanted colleterial glands are able to synthesize protein and glucoside in adult females; in adult males, however, the transplanted glands are able to synthesize only protein. They do not synthesize glucoside, even under the influence of additional juvenile hormone supplied to the male hosts by injection. Yet males produce enough juvenile hormone to promote the synthesis of protein and glucoside by colleterial gland cultured in female hosts. This was demonstrated by combining in parabiotic fusion adult males with decapitated adult females. The adult female apparently contains a factor which in the presence of juvenile hormone is a prerequisite for glucoside but not for protein synthesis. This factor is apparently also absent in nymphs of both sexes. The dependence of protein synthesis on the juvenile hormone provides a quantitative bioassay for estimating the juvenile hormone titer in all postembryonic stages of development. At present, glucoside synthesis can only be used as an indicator for the juvenile hormone concentration of adult females of different ages. The juvenile hormone presumably acts directly on the tissues of the collecterial glands.This paper is dedicated to the memory of Professor Alfred Kühn, one of the great biologists of his time, who died in Tübingen, Germany on November 22, 196

ISSN:0022-104X    

DOI:10.1002/jez.1401700305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

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

ISSN:0022-104X    

DOI:10.1002/jez.1401700306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effects of the mutant gene shaker‐1 (sh‐1) in the mouse include degeneration of the neural epithelium in the inner ear, which in places is so constructed that degeneration of minute areas, even single cells, can be identified. In Cattanach's translocation the piece of autosome 1 that is translocated onto the X‐chromosome bears the normal allele ofsh‐1, and so this gene would be expected to acquire the charateristics of sex‐linked genes in mammals. It was thought that a study ofsh‐1/‐;Dp/Xanimals might illuminate some aspect of the development of the inner ear in normal andsh‐1/sh‐1animals. Normal and affected regions were found to coexist in the organ of Corti but not in the macula of the saccule. The degree of abnormality of the macula differed from ear to ear but was quite uniform within each ear. This points to a radical difference in early development in the relationship between the otic epithelium and its innervation in the cochlea and the saccule. It also appears highly unlikely that abnormalities of the stria vascularis are responsible for the degeneration of t

ISSN:0022-104X    

DOI:10.1002/jez.1401700307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractWhen subjected to reversed light cycles, deer antlers are shed and regenerated six months out of phase with respect to the outdoor environment. They respond solely to the lighting conditions, not to temperature changes. Deer exposed to accelerated years grow antlers more frequently than normal, but in no cases do they produce them more often than every three months. When the annual light cycle is prolonged to 24 months, deer tend to grow antlers every other year in accordance with the artificial cycle. In general, deer forced to grow antlers more frequently than normal produce stunted outgrowths owing to the abbreviated years. Those maintained on extra long light cycles, however, do not grow extra large antlers.Analysis of these data suggests that the onset of antler growth is entrained by increasing day lengths in deer previously sensitized by decreasing days. However, older animals can sometimes express an endogenous yearly antler growth cycle irrespective of certain prevailing artificial lighting conditions.

ISSN:0022-104X    

DOI:10.1002/jez.1401700308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

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.

ISSN:0022-104X    

DOI:10.1002/jez.1401700309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractEffects of 6‐azauridine on isolated embryonic cells ofXenopus laeviswere examined electronmicroscopically. It has been revealed that shortly after the treatment, when the rate of RNA synthesis became reduced, a unique ultrastrutural change occurred in the nucleoli: granular component greatly decreased in amount, while fibrous component retained a rather normal, though somewhat coalesced, net‐work structure. Four to six hours later, when inhibition in the syntheses of protein and DNA became apparent, the nuclear chromatin condensed and the nucleoli became a small round mass which consisted of fibrous component alone in some cells. Finally at the tenth hour, most cells showed pycnotic feature and the nucleoli were fragmented and frequently disappeared. At this time, endoplasmic reticulum and mitochondria were also deformed and decreased in number. The significance of the nucleolar alteration observed has been discus

ISSN:0022-104X    

DOI:10.1002/jez.1401700310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

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 xenog

ISSN:0022-104X    

DOI:10.1002/jez.1401700311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY