摘要:

AbstractAnalysis of an electrophoretic variant coded by the glyceraldehyde‐3‐phosphate dehydrogenase‐2 (GAPD2) locus of the playtfish (Xiphophorus maculatus) revealed that the variant allele produced a defective subunit. As a homotetramer (from tissue extracts of homozygotes), the variant enzyme had only 12% the activity of homotetramers specified by the normal allele. In heterozygotes the defective subunits aggregated with the normal subunits to produce hybrid tetramers in the amounts expected for equal production of the two subunits by the two alleles but with the activity reduction expected according to the subunit composition. The total activities of muscle extracts in heterozygotes were reduced to about 55% of normal, consistent with that expected if neither compensatory synthesis of allelic products of theGAPD2locus nor theGAPDllocus took place. This result implies that regulation of the production of this enzyme is constitutive (produced at maximal rate) or depends on a mechanism which does not recognize the functional activity of the gene products. The absence of detectable segregation distortion suggests that the variant has no significant effect on viability, and thus may be selectively neutral, though producing in several tissues an activity deficiency of 88% in homozy

ISSN:0022-104X    

DOI:10.1002/jez.1402230102

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe effects of monoamines and adrenergic drugs on luminescent responses and rachidial contractions were investigated in the colony of the sea pansyRenilla köllikeri. Of several transmitter candidates tested, only adrenaline induced localized, phasic luminescence at low concentrations. Propranolol (1 mM) depressed adrenaline‐induced and suppressed electrically stimulated luminescence, the latter being also abolished by 6‐hydroxydopamine (6‐OHDA) and reserpine. Desmethylimipramine (DMI, 20 μM), an uptake inhibitor of adrenergic neurons, potentiated luminescent responses to both adrenaline and electrical stimulation, and induced luminescence at higher concentrations. Pargyline, a monoamine oxidase inhibitor, produced DMI‐like effects. Rachidial contractions inRenillaare biphasic events which are usually spontaneous and rhythmic, or can be induced by electrical stimulation. Noradrenaline and adrenaline enhanced the second phase of ongoing rhythmic contractions, but failed to induce contractions. Reserpine and 6‐OHDA abolished electrically stimulated luminescence, but reserpine further depressed evoked contractions while 6‐OHDA failed to affect rhythmic or evoked contractions. DMI (0.5 mM) initiated rhythmic contractile activity in quiescent preparations. These observations suggest that adrenaline or an as yet unidentified catecholamine may be involved as a neurotransmitter in luminescence control. Noradrenaline and/or adrenaline act possibly as neuromodulators for rachidial contractions in

ISSN:0022-104X    

DOI:10.1002/jez.1402230103

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

年代:1982

数据来源: WILEY

摘要:

AbstractRed cell GSH, GSH regeneration rates, and the activities of ten enzymes were measured in the red blood cells of camels and buffaloes. The activity of G6PD was found to be much higher in both the species compared to that found in other ruminants such as sheep, goats, and cattle. Although there were no significant differences in the level of red cell GSH in the two species, there was a striking difference in the rate of GSH regeneration, the mean rate of 0.162 ± 0.009 μmoles/min/gHb in the camels was significantly higher than the 0.082 ± 0.011 μmoles/min/gHb observed in the buffal

ISSN:0022-104X    

DOI:10.1002/jez.1402230104

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

年代:1982

数据来源: WILEY

摘要:

AbstractElectrophysiological and psychophysical spectral sensitivities of the teleostHemichromis bimaculatus(Pisces; Cichlidae) were determined by measurement of electroretinogram b‐wave magnitude and optomotor response threshold. The physiological and behavioral curves exhibit trivariance and trichromacy, respectively, with peaks occurring in the 460–478, 546, and 623–646 nm spectral regions. A 20‐nm shift to the red is seen in the physiological curves upon strong light adaptation, accompanied by an order of magnitude decline in overall sensitivity. Photopic physiological and behavioral sensitivities correspond in sensitivity, but differ in dominant peaks, with the red and green spectral sensitivities dominating the respective curves. The common spectral peaks correspond with suspected vertebrate photopigments, correlate with the visually oriented nuptial and parental behaviors of the cichlids, and imply cone dominance in the retina of this

ISSN:0022-104X    

DOI:10.1002/jez.1402230105

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe metabolic rates of gravid and nongravid females of two subspecies ofSceloporus aeneusexhibiting different reproductive modes (oviparity and viviparity) were compared. Both oviparous and viviparous gravid females exhibited a significant increase in oxygen consumption over that of nongravid females of either reproductive mode. Weight‐specific oxygen consumption also is greater in gravid than in nongravid females. The alteration in metabolic rate in gravid females is attributed to a fetal–maternal difference in this parameter‐that is, an altered maternal physiology associated with pregnancy.key words weight‐specific metabolism, reproduction,oxygen consumption,Sceloporus aeneus reptilia, squamata,i

ISSN:0022-104X    

DOI:10.1002/jez.1402230106

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

年代:1982

数据来源: WILEY

摘要:

AbstractMale Rosefinches, previously treated with short days (8L: 16D), were held under six different light regimes (resonance light cycles) in which a main 6‐hr photophase was combined with varying durations of scotophases (6L/6(2n + l)D)L, light phase; D, dark phase; n, number of multiples of 6D.; one group was also placed under long days (15L:9D) which served as control. Birds placed under long days as well as 6L:6D, 6L:30D, 6L:54D showed complete gonadal growthand development, while birds under 6L:18D, 6L:42D, 6L:66D showed no testicular growth and behaved as if they had been exposed to short days. These results are consistent with the Bünning hypothesis and indicate that the photoperiodic time measurement in Common Indian Rosefinches (Carpodacus erythrinus) involves an endogenous rhythm of approximately 24 hr in durati

ISSN:0022-104X    

DOI:10.1002/jez.1402230107

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

年代:1982

数据来源: WILEY

摘要:

AbstractEmbryonic axolotls (Stages 32–34) underwent surgery during which a graft of flank tissue was transferred from a donor animal to the anterior margin of the forelimb field in a host animal. Double‐posterior forelimbs containing from one to eight digits developed. These limbs were amputated at a level proximal to the elbow to assess their regenerative ability. The majority (62%) of these limbs failed to regenerate externally visible structures. Symmetrical limbs bearing five digits or more than five digits regenerated with greatest frequency (54%). Symmetrical forelimbs bearing four digits or fewer than four digits regenerated less frequently (31%). All regenerates displayed double‐posterior symmetry and usually contained fewer digits than were present in the original limb. The significance of these findings is discussed in the context of a current model for pattern regulation in epimorphic f

ISSN:0022-104X    

DOI:10.1002/jez.1402230108

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

年代:1982

数据来源: WILEY

摘要:

AbstractExperiments were performed to ascertain whether cells from the forelimb and the hindlimb of newts share a common pattern‐regulating mechanism during regeneration. In one series of experiments early digit hindlimb and forelimb blastemas were exchanged either ipsilaterally or contralaterally. In a second experimental series, a strip of forelimb skin was added to a slit in a homologous site on the hindlimb or in a site 180° removed from the position of origin, and vice versa (hindlimb skin into forelimb). After contralateral blastema exchanges, supernumerary limbs developed in addition to the limb of graft origin, whereas after ipsilateral exchanges, a single limb of graft origin regenerated. Limbs in which skin grafts were inserted into homologous sites developed normal regenerates of the host type, while in contrast, limbs with supernumerary digits regenerated from limbs which had received skin grafts in positions 180° opposite to the homologous position. The results of both experiments were dependent on the positional disparity between the graft and host tissues, and they suggest that the forelimb and hindlimb do indeed utilize a common mechanism for pattern regulat

ISSN:0022-104X    

DOI:10.1002/jez.1402230109

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe ontogeny of catalase‐containing organelles was studied by cytochemical and biochemical methods in the liver, kidney, and pancreas during the development ofRana catesbeiana. The biochemical differentiation of peroxisomes in the liver and kidney was compared to that ofXenupus laeuis. Catalase activity was localized after incubation in DAB medium and studied biochemically by a spectrophotometric method. InRana catesbeianathe number of catalase‐pos‐itive organelles per cell section is low in all three organs during premetamorphosis; their number increases substantially in the liver and kidney of froglets, while it remains almost stable in the pancreas. No further increase is observed in the adult. Biochemically, the liver, kidney, and pancreas of tadpoles exhibit, respectively, 12, 22, and 63% of the catalase activity found in the adult tissues. After metamorphosis an important increase of catalase activity is particularly noted in liver and kidney, the activity being, respectively, 43 and 77% of that of adult bullfrogs. On the other hand, no change in catalase activity in the liver and kidney is noted during the entire development ofXenopus laeuis. The present study illustrates the very different developmental pattern of catalase activity observed during the development of two anuran amphibians. The different developmental pattern of the same enzyme within the small intestine, liver, kidney, and pancreas inRana catesbeianais also str

ISSN:0022-104X    

DOI:10.1002/jez.1402230110

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe aim of this study is to explore the control mechanism which regulates, the timing of gastrulation. We wished to know whether the timing is rigidly determined within the constituting cells of the embryo or whether it is changed by intercellular communication systems. Starfish‐fused double‐embryos were formed by contact between pairs of denuded eggs with different cleavage schedules, one egg in each pair being distinguished with vital stain. Electron microscopy revealed identical ultrastructural characteristics in every cell contact: Septate junctions were found not only between cells in the contact area between the two counterparts constituting a fused embryo but also between cells within a counterpart. In fused embryos formed from stained eggs and unstained eggs with the former having started the first cleavage 30 min earlier than the latter, the stained counterparts began to invaginate about 30 min earlier than the unstained. When fused embryos were produced by putting stained eggs in contact with unstained eggs which had begun the first cleavage 2 hr later than the stained eggs, gastrulation of the stained counterparts took place about 2 hr earlier than that of the unstained counterparts. These results suggest that the timing of gastrulation is fixed within the cells of an embryo and cannot be altered in spite of the cell‐to‐cell communication that appears t

ISSN:0022-104X    

DOI:10.1002/jez.1402230111

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

年代:1982

数据来源: WILEY