共查询到20条相似文献,搜索用时 15 毫秒
1.
Parvalbumin in mouse muscle in vivo and in vitro 总被引:1,自引:0,他引:1
Marion S. Ecob-Prince Ekkehard Leberer 《Differentiation; research in biological diversity》1989,40(1):10-16
Parvalbumin is a cytosolic calcium-binding protein found in adult fast-twitch mammalian muscle. Using an antibody to paravalbumin, we have shown that its distribution in adult mouse muscles is associated with certain fibre types. It is absent from slow-twitch type 1 fibres, is absent or at low levels in fast-twitch type 2A fibres, but is present at moderate or high levels in fast-twitch type 2B fibres. When adult mouse muscle is cultured with embryonic mouse spinal cord, the regenerated fibres become innervated, express the adult fast isoform of myosin heavy chain and appear histochemically as fast-twitch fibres. We therefore investigated whether these apparently mature fibres also contained parvalbumin. Parvalbumin was not found in any fibres of twenty mature cultures, suggesting that neurotrophic activity in the absence of specific adult nerve activity patterns was insufficient to cause the expression of parvalbumin in the cultures. 相似文献
2.
Vélez-Delvalle C Marsch-Moreno M Castro-Muñozledo F Bolivar-Flores YJ Kuri-Harcuch W 《Biochemical and biophysical research communications》2008,371(3):420-424
Fibromodulin is a small leucine-rich proteoglycan that has a central role in the maintenance of collagen fibrils structure, and in regulation of TGF-β biological activity. Although, it is mainly found in cartilage and tendon, little is known regarding the expression of the fibromodulin gene in other cell types. By RT-PCR, real time PCR and immunohistochemistry, we describe the expression of the fibromodulin gene and the presence of the protein in human epidermal keratinocytes (HEK), both in culture and in normal human epidermis. Our results show, for the first time, that fibromodulin gene is constantly expressed in HEK during culture time. Immunostaining showed that fibromodulin is located intracytoplasmically in basal and stratified keratinocytes of the growing colonies, confluent cultures, and epidermis in vivo. The expression and intracellular localization of fibromodulin in HEK is a new finding and opens new possible biological roles for the SLRP family. 相似文献
3.
MAUSER CL 《California medicine》1950,73(5):421-424
Bronchial asthma in children may be difficult to diagnose. Education of the parents regarding allergic conditions, specifically bronchial asthma, is exceedingly important in order to assure satisfactory treatment and clinical results. Chest symptoms of unexplained origin in early life should immediately arouse suspicion of allergic disease. Other causes of asthmatic symptoms must be borne in mind and excluded before a positive diagnosis of bronchial asthma is established. Of the many factors to be considered in investigating a child with asthma, a comprehensive history is most essential. The climate to which the patient is exposed and the psychic influences must be taken into account. Physical examination, x-ray films and laboratory procedures should be carefully executed. Skin testing, especially with food allergens, should not be relied upon to give all the information in allergic disease. Some form of diet trial, such as elimination diets, should be used if sensitivity to food is suspected. 相似文献
4.
J Arnold M Diop M Kodjovi J Rozier 《Comptes rendus des séances de la Société de biologie et de ses filiales》1980,174(6):983-992
The isolated malabsorption of the lactose in the adult is an hereditary feature while is not found often in the white people but is spread out in black Africa. In Senegal, a ratio of about 29% is verified, changing according to the ethnic composition. Only the Peuhls, of semitic origin, show a full tolerance to lactose. 相似文献
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This study uses data from the 1992-93 National Family Health Survey to assess trends in consanguinity in the South Indian states of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu. In Kerala, the frequency of consanguineous marriages is very low and one type of preferred marriage of the Dravidian marriage system uncle niece marriage--is conspicuously absent. In the other states of South India, consanguinity and the coefficient of inbreeding are high. While no change in consanguinity is observed during the past three to four decades in Karnataka, a definite decline is observed in Andhra Pradesh and Tamil Nadu. Due to recent changes in the demographic and social situation in these states, this decline in consanguinity is likely to continue. 相似文献
7.
Flow in arteries in the presence of stenosis 总被引:1,自引:0,他引:1
Of concern in the paper is a study of blood flow in an arterial segment having a stenosis. The artery is modelled as an initially stressed orthotropic elastic tube filled with a viscous incompressible fluid. The analysis is based on the assumption of the presence of a mild stenosis in the artery. Blood is treated as a Newtonian fluid. The effect of the surrounding connective tissues on the motion of the wall has been incorporated. Propagation of small amplitude harmonic waves, generated due to the flow of blood where the wave length is large compared to the radius of the arterial segment, is is considered in detail. 相似文献
8.
Role of Phytohormones in Sex Differentiation in Plants 总被引:1,自引:0,他引:1
The role of phytohormones in sex expression in plants is briefly surveyed. The interaction of hereditary and environmental factors in sex expression is considered. A major role of gibberellins and cytokinins in the regulation of sex expression in dioecious and monoecious flowering plants and in some muscoids is demonstrated. The evidence for the effect of other phytohormones and physiologically active compounds on sex expression in plants is examined. 相似文献
9.
David J. McKenzie Yangfan Zhang Erika J. Eliason Patricia M. Schulte Guy Claireaux Felipe R. Blasco Julie J.H Nati Anthony P. Farrell 《Journal of fish biology》2021,98(6):1536-1555
Intraspecific variation in key traits such as tolerance of warming can have profound effects on ecological and evolutionary processes, notably responses to climate change. The empirical evidence for three primary elements of intraspecific variation in tolerance of warming in fishes is reviewed. The first is purely mechanistic that tolerance varies across life stages and as fishes become mature. The limited evidence indicates strongly that this is the case, possibly because of universal physiological principles. The second is intraspecific variation that is because of phenotypic plasticity, also a mechanistic phenomenon that buffers individuals’ sensitivity to negative impacts of global warming in their lifetime, or to some extent through epigenetic effects over successive generations. Although the evidence for plasticity in tolerance to warming is extensive, more work is required to understand underlying mechanisms and to reveal whether there are general patterns. The third element is intraspecific variation based on heritable genetic differences in tolerance, which underlies local adaptation and may define long-term adaptability of a species in the face of ongoing global change. There is clear evidence of local adaptation and some evidence of heritability of tolerance to warming, but the knowledge base is limited with detailed information for only a few model or emblematic species. There is also strong evidence of structured variation in tolerance of warming within species, which may have ecological and evolutionary significance irrespective of whether it reflects plasticity or adaptation. Although the overwhelming consensus is that having broader intraspecific variation in tolerance should reduce species vulnerability to impacts of global warming, there are no sufficient data on fishes to provide insights into particular mechanisms by which this may occur. 相似文献
10.
Sven-Axel Bengtson Anders Nilsson Sten Nordström Sten Rrundgren 《Journal of Zoology》1976,178(2):173-188
Polymorphism for shell colour and banding pattern in Cepaea hortensis was studied in a confined area in south Iceland. Morph freqquencies can be related to habitat. Yellow unbanded snails are more frequent in grassland and herb meadows thatn in "darker" habitats such as in ddense Angelica . Fused banding is relatively more frequent in "daarker" habitats. Predation by birds is not known to occur and rodent predation in winter or genetic drift cannot explain the observed correlations. Habitats differ in their microclimate and it is suggested that climatic selection is important. Differences in morph frequencies between juvenile and adult snails support this view. 相似文献
11.
《Parasitology international》2014,63(3):533-536
Little is known about the genetic variability of the soil-transmitted nematode, Strongyloides stercoralis, in humans. We sequenced portions of the small subunit rDNA (SSU), including the hyper variable regions (HVR) I and IV from S. stercoralis larvae derived from individuals living in a rural setting in Cambodia. We identified three polymorphic positions, including a previously reported one within the HVR I. HVR IV was invariable. Six different SSU alleles existed in our sample. Although different genotypes of S. stercoralis were found in the same individuals, no heterozygous larvae were found. This indicates that there is no or very little interbreeding between the different genotypes. Further studies are needed to examine if this is because sexual reproduction, which is facultative, is rare in our study area's S. stercoralis population or because what is considered to be S. stercoralis today is actually a complex of closely related species or subspecies. 相似文献
12.
Sensory gating is a process in which the brain’s response to a repetitive stimulus is attenuated; it is thought to contribute to information processing by enabling organisms to filter extraneous sensory inputs from the environment. To date, sensory gating has typically been used to determine whether brain function is impaired, such as in individuals with schizophrenia or addiction. In healthy subjects, sensory gating is sensitive to a subject’s behavioral state, such as acute stress and attention. The cortical response to sensory stimulation significantly decreases during sleep; however, information processing continues throughout sleep, and an auditory evoked potential (AEP) can be elicited by sound. It is not known whether sensory gating changes during sleep. Sleep is a non-uniform process in the whole brain with regional differences in neural activities. Thus, another question arises concerning whether sensory gating changes are uniform in different brain areas from waking to sleep. To address these questions, we used the sound stimuli of a Conditioning-testing paradigm to examine sensory gating during waking, rapid eye movement (REM) sleep and Non-REM (NREM) sleep in different cortical areas in rats. We demonstrated the following: 1. Auditory sensory gating was affected by vigilant states in the frontal and parietal areas but not in the occipital areas. 2. Auditory sensory gating decreased in NREM sleep but not REM sleep from waking in the frontal and parietal areas. 3. The decreased sensory gating in the frontal and parietal areas during NREM sleep was the result of a significant increase in the test sound amplitude. 相似文献
13.
Sequence variation in ZFX introns in human populations 总被引:3,自引:2,他引:1
DNA variation in human populations was studied by examining the last intron
of the ZFX gene (about 1, 151 bp) with a worldwide sample of 29
individuals. Only one polymorphic site was found, which is located in an
Alu sequence. This polymorphism is present at an intermediate frequency in
all populations studied, and could be a shared polymorphism or due to
migration among populations in Asia, Europe, and Africa. The nucleotide
diversity is 0.04%, supporting the view that the level of nucleotide
variation in nuclear DNA is very low in humans. From the sequence data, the
age (T) of the most recent common ancestor of the sampled sequences is
estimated: the mode of T is about 306,000 years, and the 95% confidence
interval of T is 162,000-952,000 years. This mode estimate is considerably
older than the estimates from Y- linked sequences.
相似文献
14.
Ca-pumps in smooth muscle: one in plasma membrane and another in endoplasmic reticulum 总被引:4,自引:0,他引:4
A K Grover 《Cell calcium》1985,6(3):227-236
For several years it has been debated whether the Ca-pump in smooth muscle is located in the plasma membrane or in the endoplasmic reticulum (alias sarcoplasmic reticulum). Experimental evidence using skinned smooth muscle cells and subcellular membrane fractions isolated from a number of smooth muscles is reviewed here to hopefully resolve this issue. The inescapable conclusion is that there are two modes of nonmitochondrial ATP-dependent Ca-transport. The first one, unaffected by oxalate, is localized in the plasma membranes and the second, potentiated by oxalate, is localized in the endoplasmic reticulum. Clear experiments to delineate the roles of the two pumps in the excitation-contraction cycle of the smooth muscle remain to be conducted. 相似文献
15.
Variation in aggressiveness in house mouse populations 总被引:1,自引:0,他引:1
PAUL F. BRAIN STEFANO PARMIGIANI 《Biological journal of the Linnean Society. Linnean Society of London》1990,41(1-3):257-269
Clearly the ability of 'house mice' to vary their social structures is an important feature contributing to their success in a wide range of habitats. Social structure is strongly influenced by aggressiveness and other behaviours in male and female mice. Material is presented illustrating how genotype, intrauterine location and social experiences influence dyadic encounters in this 'species'. 相似文献
16.
L. F. Kurilo 《Human genetics》1981,57(1):86-92
Summary Ninety-seven female embryos and foetuses aged 6–40 weeks were quantitatively analyzed for germ cell development, mitotic activity in the ovary, and dynamics of chromosome transformations in oocytes at the stages of meiotic prophase I and follicle genesis. For the first time, chronology of oocytes dynamics at the stage of the preleptotene chromosome condensation and decondensation is described. Oocytes at the leptotene stage occur in embryos aged 10–11 weeks. Oocyte transfer at the zygotene and pachytene stages starts by 10.5–11 and 11.5–13 weeks, respectively. Their number is maximum after 26 weeks and by the 40th week decreases to just single oocytes. The first oocytes at the diplotene stage appear in foetuses aged 11.5–12 weeks. Oocyte transition to the dictyotene stage is observed in single oocytes after 16 weeks of development, but active bivalent decondensation begins after 26 weeks.The formation of a follicular layer takes place not earlier than around the oocyte at the diplotene stage. Follicle genesis occurs after 11–12 weeks. Transformation of primordial follicles into primary ones is intensified after 19–20 weeks. By the moment of birth, the majority of oocytes in the human ovary are contained in primary follicles, and only a few are contained in primordial ones. The number of secondary and tertiary antral follicles is extremely small. The dynamics of degeneration of germ cells throughout intra-uterine development is also described. 相似文献
17.
Nicolaiciuc D Popa MI Popa L 《Roumanian archives of microbiology and immunology》1999,58(3-4):289-296
Malaria is the world's most important tropical parasitic disease. Malaria is a public health problem today in more than 90 countries. Worldwide prevalence of the disease is estimated to be in the order of 300-500 million clinical cases each year. Malaria is endemic in a total of 101 countries and territories. In Romania, malaria does not represent an important public health problem. In 1999, there were reported a total number of 32 malaria cases in Romanian people. 78% from these recognized as etiological agent Pl. falciparum. The malaria cases imported from Turkey (5) have had as etiological agent Pl. vivax. The most affected age group is between 21-50 years and a distribution by profession shows that sailor personnel accounts for 65.6% of all cases. Africa remains the most important endemic region from where the malaria cases in Romanian people are imported. An adequate chemoprophylaxis is not, yet, easy to obtain for Romanian people who are travelling abroad in endemic countries because of the lack of specific drugs (especially for resistant forms of Pl. falciparum). Even if the Romanian Ministry of Health had elaborated orders regarding malaria and Cloroquine is the usual drug administered, as chemoprophylaxis, to Romanian people who travel abroad, in each year in our country appears around 30-60 imported malaria cases. That is the cause why Romanian Ministry of Health wants to solve this problem which is the major cause of the malaria cases in Romanian people. 相似文献
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Cepaea hortensis (Mull) is found in Spain only in the western part of the Iberian mountain range. This is the southernmost limit of its range. The most frequent colour is yellow, brown being very rare. The most frequent band patterns are 12345, fused banded and unbanded. There are associations between maximum and minimum temperatures and pink and effectively unbanded yellow phenotypes. The populations may be grouped into two zones, one located in the north and the other in the south of the sampled area. Visual predation was not observed. The marginal populations studied by us were compared with others from Northern Europe, and it was observed that pink snails are more frequent at the southern limit, and unbanded ones at the northern limit. This was interpreted as a climatic selection. 相似文献
20.
Xubin Hou Tatsuya Katahira Jun Kimura Harukazu Nakamura 《Development, growth & differentiation》2009,51(9):833-840
Coactosin is a 17 kDa actin binding protein that belongs to the actin depolymerizing factor/cofilin homology family. Coactosin inhibits barbed‐end capping of actin filament, and is involved in actin polymerization. Coactosin is expressed in cephalic and trunk neural crest cells, cranial ganglia and dorsal root ganglia. Coactosin is also expressed in the cells that are forming mesonephric duct, and endodermal cells. Immunocytochemistry with anti‐Coactosin antibody shows that Coactosin is localized in the cytoplasm, and associated with actin stress fibers in cultured neural crest cells. Coactosin is also expressed in the axon of oculomotor nerve and trigeminal nerve. In the growth cone of the oculomotor nerve axons, both Coactosin mRNA and protein were localized, which is indicative of the role of Coactosin in pathfinding of the growth cone. Coactosin is expressed in those that require dynamic and highly coordinated regulation of actin cytoskeleton, that is, neural crest cells, cells in the tip of the mesonephros, endodermal cells and axons. 相似文献