摘要:

AbstractMorphological and physiological data were used to establish which motor neurons innervate known wing elevator and depressor muscles. Nerves to identified muscles were backfilled to establish the neuropilar morphology of neurons innervating each muscle. Individual motor neurons were recorded intra‐cellularly during flight sequences and then filled. The intracellularly identified cell was then matched with backfilled cells that had similar ganglionic morphology, exited the same nerve root, and had the same function during the flight cycle. In this way the target muscle of five elevator and five depressor motor neurons was establishe

ISSN:0022-104X    

DOI:10.1002/jez.1402250302

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

年代:1983

数据来源: WILEY

摘要:

AbstractEther treatment of embryos in successive generations results in the progressive increase in penetrance of thebithoraxphenocopy in both a massbred and an inbred line ofDrosophila melanogasterwithout artificial selection for the phenocopy. The involvement of cumulative cytoplasmic modifications is suggested by the results of recipiocal crosses between the treated massbred line and its foundation stock, and by the lingering effects observed when ether treatment is withheld in later generations.Regression analyses showed that the effect of successive generations of ether treatment on penetrance is cumulative and direct, and not mediated by possible effects on viability.Ether treatment carried out on embryos at four consecutive age intervals in the 14th generation suggests that the effects of long‐term etherisation are as follows: an increased tendency to phenocopy at all ages tested; an extension of the critical period during which the phenocopy can be induced; and an increased resistance to the lethal effects of ether in older embryos.The remarkable consistency in every aspect of the response in the two different lines—one containing at least 20 times as much genetic variation as the other—points to the existence of systematic organismic properties which do not depend on specific alleles in specific genes.The possible evolutionary significance of our results is disc

ISSN:0022-104X    

DOI:10.1002/jez.1402250303

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

年代:1983

数据来源: WILEY

摘要:

AbstractEach tissue of the sea mouse,Aphrodite aculeata, contains a single cytoplasmic dehydrogenase acting at the pyruvate branchpoint: Alanopine dehydrogenase (ADH) occurs in longitudinal muscle, nerve, and elytra, and strombine dehydrogenase (SDH) characterizes pharynx and intestine. Lactate and octopine dehydrogenases were not detected in any tissue. ADH from muscle and SDH from pharynx were partially purified. The two enzymes had the same molecular weight, 44,000 ± 4,000 but differed in isolelectric point. Although similar in keto acid specificity, the enzymes differed strongly in amino acid specificity. Pharynx SDH showed a very high specificity for glycine, all other alternative amino acids showing very high apparent Kms and/or low Vmaxs. Muscle ADH, however, displayed high velocities and relatively low apparent Kms with L‐alanine, L‐serine, L‐threonine, and L‐cysteine. Amino acid analysis of the tissues showed that serine and threonine contents were high enough in muscle to suggest that these amino acids might be alternative substrates to alanine in vivo; only glycine, present at 382 μmol/g in pharynx, is likely to be a physiological substrate for SDH, however. Absolute Kms for L‐alanine, glycine, and pyruvate were 2.75 ± 0.03, 285 ± 6, and 0.2 ± 0.006 for muscle ADH and 130 ± 2.2, 26 ± 1 and 0.15 ± 0.005 for pharynx SDH. In the reverse direction, apparent Kms formeso‐alanopine, D‐strombine, and NAD, at pH 9.5, were 1.68 ± 0.06, 87.0 (n = 1), and 0.75 ± 0.03 for ADH and 6.75 ± 0.20, 7.57 ± 0.07, and 0.54 ± 0.02 for SDH. The enzymes also differed strongly in effects of inhibitors.Meso‐alanopine, L‐lactate, and D‐lactate were strong inhibitors of the forward reaction for muscle ADH. Pharynx SDH, however, was strongly inhibited bymeso‐alanopine and iminodiacetic acid but showed only weak inhibition by D‐ or L‐

ISSN:0022-104X    

DOI:10.1002/jez.1402250304

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

年代:1983

数据来源: WILEY

摘要:

AbstractA comparative study of catalytic properties of the sperm‐specific lactate dehydrogenase (EC 1.1.1.27) isozyme X or C4from a variety of animals (boar, bull, goat, Guinea pig, man, mouse, pigeon, rabbit, and rat) is presented. Optimum concentration and Km values for pyruvate, inhibition by substrate, and activity against analog substrates (α‐ketoacids with linear and branched chains from 4 to 6 carbon atoms) for isozyme X of different species showed significant differences. The observed properties are correlated with available evidence on the metabolic role of the en

ISSN:0022-104X    

DOI:10.1002/jez.1402250305

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe ϕ keratins extracted from individual turtles and snakes were compared. The extent and nature of the molecular differentiation associated with the production of structurally distinct epidermal tissues was determined. The electrophoretic comparisons, molecular weight, and chemical fractionation indicate that these tissues contain unique proportions of the constituent keratin monomers specific to each species. This pattern of differentiation is similar to that previously observed for avian scale, claw, and beak, and for mammalian horn and hoof. This suggests that several “scale‐like” structures with distinctive chemical properties may be produced by a single individual without the synthesis of wholly unique proteins. The implications of these observations for the evolution of mammalian hair and avian feathers are dis

ISSN:0022-104X    

DOI:10.1002/jez.1402250306

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

年代:1983

数据来源: WILEY

摘要:

AbstractHibernation inLacerta viviparafrom Massif Central (1,000–1,200 m) lasts 6–7 months and is immediately followed by vitellogenesis, gestation, and parturition within a short period of time (May–August). Suppression of hibernation by maintaining females in active life (food and high temperatures) inhibits the resumption of ovarian growth in spring: i.e., the reproductive system remains indefinitely refractory to high temperatures. In order for vitellogenesis to be completed, females need to hibernate below S–10°C with sufficient duration (“amount of cold” thresholds). The prolongation of the exposure of females to low temperature beyond the minimal stay gradually improves their ability to complete vitellogenesis: The number of females responding increases, and the heat requirement for the onset of ovarian grow

ISSN:0022-104X    

DOI:10.1002/jez.1402250307

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

年代:1983

数据来源: WILEY

摘要:

AbstractEpidermal‐thyroid relationships were studied in thyroidec‐tomized (;Tx)Ptyas korroskept at 23°C by observing changes in shedding frequency (;SF), body weight, oxygen consumption rate (;OCR), and postsurgical survival. Tx animals showed increased SFs but lost weight and eventually died, as did Tx animals receiving 3‐mono‐iodotyrosine injections. However, injections of 3, 5‐diiodothyronine inhibited shedding and the animals survived longer. OCRs were similar in all control and experimental groups. It is concluded that among thyroid secretions, only iodothyronines inhibit shedding. Snake shedding is concluded not to reflect general metabolic status as it does

ISSN:0022-104X    

DOI:10.1002/jez.1402250308

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

年代:1983

数据来源: WILEY

摘要:

AbstractExposure ofXenopus laevistadpoles to thiosemicarbazide (TSC), at concentrations from 10 to 75 mg/liter, causes an inhibition of metamorphosis and produces the classic manifestations of the experimental disease, osteolathyrism. Concentration‐dependent effects of TSC exposure are observed in growth rate and in the severity of the osteolathyrogenic effect. Concentrations allowing the most rapid growth produce the more extreme osteolathyrogenic defects. Osteolathyrism in these animals is identical in characteristics to the condition described in a wide variety of vertebrate species.InXenopus, osteolathyrism is expressed morphologically as anomalies in bone development, skeletal conformation, and abnormal connective tissue organization in the aorta wall. The underlying defect responsible for these observations is apparently a perturbation of collagen fiber formation and maturation, as evidenced ultrastructurally by aberrant distribution and packing of collagen fibers. It is suspected that TSC produces this effect by altering the availability of copper ion, a cofactor to lysyl oxidase, an essential enzyme for intermolecular cross‐linking of procollagen. This step in collagen metabolism has been consistently implicated as the site of action of several osteolathyrogenic agents.Xenopustadpoles present a classic response to this known osteolathyrogen and demonstrate a high degree of uniformity of response within the experimental groups. In view of the developmentally significant events accessible with this system and inherent logistic and economical advantages, the metamorphosing tadpole ofXenopusholds considerable potential for the experimental analysis of teratogenic agents and eve

ISSN:0022-104X    

DOI:10.1002/jez.1402250309

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe organotypic culture of the gastric region is carried out on premetamorphicDiscoglossus pictuslarvae. Adding thyroxine to the culture medium provokes various transformations. On the cytological level, the reactions observed, which are variable depending on the cell category concerned, can be divided into two types of phenomena: histolytic and histogenetic. Auto‐phagia linked to lysosome intervention is frequently found among the histolytic processes. Autophagic vacuoles and residual bodies are observed. The gastric lumen is filled with deteriorated cells that probably come from the degeneration of the tadpole epithelium (primary epithelium). The incorporation of tritiated thymidine makes it possible to study the evolution of cell proliferation in the control and in the thyroxinated cultures. After a 1–2 day latency period, possibly due to the adjustment of the tissue to the culture environment, the incorporation of the radioprecursor H3‐thymidine into the epithelium and the tunica muscularis of thyroxine‐treated gut tissue increased on day 3, reached a maximum on day 5, and then dropped slightly on day 7. In the control cultures H3‐thymidine incorporation showed the same pattern but lower levels on the same days. The histolytic phenomena induced by thyroxine in vitro are comparable to those of natural metamorphosis. On the other hand, the histogenetic phenomena are incomplete. Proliferating and transitional phases occur but neoformated (or secondary) epithelium does not replace the degenerated primary epithelium, whatever the cul

ISSN:0022-104X    

DOI:10.1002/jez.1402250310

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

年代:1983

数据来源: WILEY

摘要:

AbstractExperiments were designed to determine the maximum survival time and extent of limb regeneration of well‐fed adult newts (Notophthal‐mus viridescens) after complete hypophysectomy.Adult newts were either well‐fed or fasted for 3 weeks at which time hypophysectomies were performed. Forelimbs were amputated 5 days posthypophy‐sectomy. Fasted hypophysectomized newts did not survive beyond 4 weeks, and limb regeneration was either absent or abortive. All of the well‐fed newts survived to 3 weeks posthypophysectomy, and even at 6 weeks posthypophy‐sectomy showed 30% survival. In the complete absence of the pituitary gland, many of the fed newts regenerated limbs to digit stages. It is concluded that pituitary hormones are not an absolute requirement for limb regeneration of adult newts. Newts in good nutritional condition at the time of hypophysectomy survive longer and their limbs regenerate to more adva

ISSN:0022-104X    

DOI:10.1002/jez.1402250311

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

年代:1983

数据来源: WILEY