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91.
92.
Hanno Würbel Markus Stauffacher Dietrich von Holst 《Ethology : formerly Zeitschrift fur Tierpsychologie》1996,102(3):371-385
The ontogeny of two stereotypic patterns, wire-gnawing and jumping, was studied in 24 laboratory mice: six males and six females each of two closely related outbred strains, kept under standard housing conditions, a conventional albino strain (ICR) and a nude, athymic mutant (ICR nu; hereafter: NU). All 24 individuals developed wire-gnawing after weaning at 20 d of age. In ICR one female and in NU five males and three females additionally developed jumping. ICR developed wire-gnawing between the age of 20 and 30 d, in NU jumping started at the age of 20 d, but intense jumping and wire-gnawing comparable to that of ICR did not develop in NU before the age of 40–50 d. Within each strain there was no significant difference between males and females with respect to the development of stereotypic behaviour. By contrast, ICR showed significantly more wire-gnawing but less jumping than NU. Stereotypy level increased with age up to a mean of 10.7 % of total activity in ICR and up to 7.4 % in NU at 100 d of age. However, there was huge inter- and intra-individual variability with respect to all parameters assessed in this study, i.e. total duration, number of bouts and bout length of the two stereotyped patterns. Wire-gnawing developed from outside-directed explorative climbing at the cage lid, whereas the source behaviour pattern (Mason 1991 a, Anim. Behav. 41, 1015–1037) of jumping was outside-directed explorative rearing at the cage wall. At 20 d of age, before the onset of stereotypy development, ICR showed significantly more climbing but less rearing than NU. Physical retardation of NU at weaning may account for decreased climbing ability during early ontogeny, and hence for the retarded development of wire-gnawing. The difference in early experience with either of the two patterns rather than genetic effects may be responsible for the qualitative difference between the strains with respect to the form of later stereotypy. 相似文献
93.
Retinoic acid (RA) has been known to play an important role in cellular growth and differentiation as well as in vertebrate development. Many in vitro cell cultures also respond to RA by differentiating. Perhaps the most widely studied of these cultures are embryonal carcinoma (EC) cells. We have used an RA-hypersensitive EC cell mutant, created by retroviral insertion, to analyze the activity of the identifiable components in the RA response pathway. We have analyzed the mRNA expression patterns of the retinoic acid receptors (RARs) α, β, and γ, the retinoid X receptors (RXRs) α, β, and γ, and the cellular retinoic acid binding proteins (CRABPs) I and II. Our results indicate that CRABP I, RAR β, and RAR γ mRNAs are expressed differentially between parent and RA-hypersensitive mutant cells. All three messages are present at higher basal levels and at earlier times after RA addition in the mutant relative to parental cells. All other elements examined are equivalently expressed. Therefore analyses of the expression patterns of CRABPs, RARs, and RXRs in these RA-hypersensitive cells point to the probable importance of CRABP I, RAR β, and RAR γ in the RA induction pathway and also indicate that CRABP II and RXR γ are not likely to be critical elements in the early differentiative response of cells to RA. 相似文献
94.
Borja Mateos Ganeko Bernardo-Seisdedos Valentin Dietrich Nicanor Zalba Gabriel Ortega Francesca Peccati Gonzalo Jiménez-Osés Robert Konrat Martin Tollinger Oscar Millet 《Biophysical journal》2021,120(10):2067-2077
Protein oligomerization processes are widespread and of crucial importance to understand degenerative diseases and healthy regulatory pathways. One particular case is the homo-oligomerization of folded domains involving domain swapping, often found as a part of the protein homeostasis in the crowded cytosol, composed of a complex mixture of cosolutes. Here, we have investigated the effect of a plethora of cosolutes of very diverse nature on the kinetics of a protein dimerization by domain swapping. In the absence of cosolutes, our system exhibits slow interconversion rates, with the reaction reaching the equilibrium within the average protein homeostasis timescale (24–48 h). In the presence of crowders, though, the oligomerization reaction in the same time frame will, depending on the protein's initial oligomeric state, either reach a pure equilibrium state or get kinetically trapped into an apparent equilibrium. Specifically, when the reaction is initiated from a large excess of dimer, it becomes unsensitive to the effect of cosolutes and reaches the same equilibrium populations as in the absence of cosolute. Conversely, when the reaction starts from a large excess of monomer, the reaction during the homeostatic timescale occurs under kinetic control, and it is exquisitely sensitive to the presence and nature of the cosolute. In this scenario (the most habitual case in intracellular oligomerization processes), the effect of cosolutes on the intermediate conformation and diffusion-mediated encounters will dictate how the cellular milieu affects the domain-swapping reaction. 相似文献
95.
Two genera, Dayus Mahmood, 1967 and Znana Dworakowska, 1994 of the leafhopper tribe Empoascini (Hemiptera: Cicadellidae: Typhlocybinae) are reviewed. One new species of each genus, Dayus furcatus sp. nov. and Znana furca sp. nov., are described from Thailand. A checklist and distribution summary of Dayus Mahmood species is given. Male habitus photos and illustrations of male genitalia of the two new species and notes on allied species are also provided. 相似文献
96.
Nine genera and twenty-two species of heptageniid mayflies from Thailand are defined in this present work as well as one suggested further subgenus, Compsoneuria (Siamoneuria) kovaci (species “incertae sedis”) including some particular characters. Taxonomic remarks, diagnoses, line drawings of key characters, distribution, habitat and biological data, and a larval key to the genera and species are provided. The chorionic eggs of eight genera and eight species were observed and shown using a scanning electron microscope. 相似文献
97.
98.
Eva C. Schulte Immanuel Stahl Darina Czamara Daniel C. Ellwanger Sebastian Eck Elisabeth Graf Brit Mollenhauer Alexander Zimprich Peter Lichtner Dietrich Haubenberger Walter Pirker Thomas Brücke Benjamin Bereznai Maria J. Molnar Annette Peters Christian Gieger Bertram Müller-Myhsok Claudia Trenkwalder Juliane Winkelmann 《PloS one》2013,8(11)
Approximately 20% of individuals with Parkinson’s disease (PD) report a positive family history. Yet, a large portion of causal and disease-modifying variants is still unknown. We used exome sequencing in two affected individuals from a family with late-onset familial PD followed by frequency assessment in 975 PD cases and 1014 ethnically-matched controls and linkage analysis to identify potentially causal variants. Based on the predicted penetrance and the frequencies, a variant in PLXNA4 proved to be the best candidate and PLXNA4 was screened for additional variants in 862 PD cases and 940 controls, revealing an excess of rare non-synonymous coding variants in PLXNA4 in individuals with PD. Although we cannot conclude that the variant in PLXNA4 is indeed the causative variant, these findings are interesting in the light of a surfacing role of axonal guidance mechanisms in neurodegenerative disorders but, at the same time, highlight the difficulties encountered in the study of rare variants identified by next-generation sequencing in diseases with autosomal dominant or complex patterns of inheritance. 相似文献
99.
Benjamin J. Wheaton Natassya M. Noor Sophie C. Whish Jessie S. Truettner W. Dalton Dietrich Moses Zhang Peter J. Crack Katarzyna M. Dziegielewska Norman R. Saunders 《PloS one》2013,8(8)
Complete spinal transection in the mature nervous system is typically followed by minimal axonal repair, extensive motor paralysis and loss of sensory functions caudal to the injury. In contrast, the immature nervous system has greater capacity for repair, a phenomenon sometimes called the infant lesion effect. This study investigates spinal injuries early in development using the marsupial opossum Monodelphis domestica whose young are born very immature, allowing access to developmental stages only accessible in utero in eutherian mammals. Spinal cords of Monodelphis pups were completely transected in the lower thoracic region, T10, on postnatal-day (P)7 or P28 and the animals grew to adulthood. In P7-injured animals regrown supraspinal and propriospinal axons through the injury site were demonstrated using retrograde axonal labelling. These animals recovered near-normal coordinated overground locomotion, but with altered gait characteristics including foot placement phase lags. In P28-injured animals no axonal regrowth through the injury site could be demonstrated yet they were able to perform weight-supporting hindlimb stepping overground and on the treadmill. When placed in an environment of reduced sensory feedback (swimming) P7-injured animals swam using their hindlimbs, suggesting that the axons that grew across the lesion made functional connections; P28-injured animals swam using their forelimbs only, suggesting that their overground hindlimb movements were reflex-dependent and thus likely to be generated locally in the lumbar spinal cord. Modifications to propriospinal circuitry in P7- and P28-injured opossums were demonstrated by changes in the number of fluorescently labelled neurons detected in the lumbar cord following tracer studies and changes in the balance of excitatory, inhibitory and neuromodulatory neurotransmitter receptors’ gene expression shown by qRT-PCR. These results are discussed in the context of studies indicating that although following injury the isolated segment of the spinal cord retains some capability of rhythmic movement the mechanisms involved in weight-bearing locomotion are distinct. 相似文献
100.