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1.
In our previous works, we reported that compensation of the geomagnetic field to a level less than 0.4?μT (“zero magnetic field,” or ZMF) affected human cognitive processes. ZMF exposure increased the number of errors and the task processing time by 2.4% in average. However, in the array of the magnetic effects calculated from the experimental data, some readings have been found to deviate from the mean magnetic effect by more than three standard deviations. This finding could give rise to doubt as to whether the magnetic effect observed was a mere sequence of the presence of such unlikely data values. In the present work we examine the results of the unlikely data elimination and show that the corrected magnetic effect in tested humans remains statistically significant, though at a reduced magnitude 1.5%.  相似文献   

2.
In amphibians and other vertebrates, neural development is induced in the ectoderm by signals coming from the dorsal mesoderm during gastrulation. Classical embryological results indicated that these signals follow a “vertical” path, from the involuted dorsal mesoderm to the overlying ectoderm. Recent work with the frog Xenopus laevis, however, has revealed the existence of “planar” neural-inducing signals, which pass within the continuous sheet or plane of tissue formed by the dorsal mesoderm and presumptive neurectoderm. Much of this work has made use of Keller explants, in which dorsal mesoderm and ectoderm are cultured in a planar configuration with contact along only a single edge, and vertical contact is prevented. Planar signals can induce the full anteroposterior (A-P) extent of neural pattern, as evidenced in Keller explants by the expression of genes that mark specific positions along the A-P axis. In this review, classical and modern molecular work on vertical and planar inductionwill be discussed. This will be followed by a discussion of various models for vertical induction and planar induction. It has been proposed that the A-P pattern in the nervous system is derived from a parallel pattern of inducers in the dorsal mesoderm which is “imprinted” vertically onto the overlying ectoderm. Since it is now known that planar signals can also induce A-P neural pattern, this kind of model must be reassessed. The study of planar induction of A-P pattern in Xenopus embryos provides a simple, manipulable, two-dimensional system in which to investigate pattern formation. © 1993 John Wiley & Sons, Inc.  相似文献   

3.
Cilia on the ventral surface of the hypotrich ciliate Euplotes are clustered into polykinetids or compound ciliary organelles, such as cirri or oral membranelles, used in locomotion and prey capture. A single polykinetid may contain more than 150 individual cilia; these emerge from basal bodies held in a closely spaced array within a scaffold or framework structure that has been referred to as a basal‐body “cage”. Cage structures were isolated free of cilia and basal bodies; the predominant component of such cages was found on polyacrylamide gels to be a 45‐kDa polypeptide. Antisera were raised against this protein band and used for immunolocalizations at the light and electron microscope levels. Indirect immunofluorescence revealed the 45‐kDa polypeptide to be localized exclusively to the bases of the ventral polykinetids. Immunogold staining of thin sections of intact cells further localized this reactivity to filaments of a double‐layered dense lattice that appears to link adjoining basal bodies into ordered arrays within each polykinetid. Scanning electron microscopy of isolated cages reveals the lower or “basal” cage layer to be a fine lacey meshwork supporting the basal bodies at their proximal ends; adjoining basal bodies are held at their characteristic spacing by filaments of an upper or “medial” cage layer. The isolated cage thus resembles a miniature test‐tube rack, able to accommodate varying arrangements of basal‐body rows, depending on the particular type of polykinetid. Because of its clear and specific localization to the basal‐body cages in Euplotes, we have termed this novel 45‐kDa protein “cagein”.  相似文献   

4.
M. Kodama  H. Noda  T. Kamata 《Biopolymers》1978,17(4):985-1002
The conformation of amylose in aqueous solution has been found to be dependent on its molecular weight. When the molecular weight of amylose is outside of the so-called “dissolving gap” described by Burchard (6500<Mr<160,000) it behaves as a random coil, whereas when its molecular weight is within the “dissolving gap,” it easily aggregates forming a rigid coil which is the B-type (retrograded) amylose. The conformation of this rigid coil is suggested to be a double helix.  相似文献   

5.
Electromyograms (EMGs) are measured by bipolar surface electrodes that quantify potential differences. Bipolar potentials over penniform muscles may be associated with errors. Our assumption was that muscle activity can be quantified more reliably and with a higher spatial resolution using current measurements.The purpose of this work is: (a) to introduce the concept of current measurements to detect muscle activity, (b) to show the coherences observed over a segment of a typical penniform muscle, the gastrocnemius medialis where one would expect a synchronicity of the activation, and (c) to show the amount of mixing that is caused by the finite inter electrode resistance.A current amplifier was developed. EMGs were recorded at 40% of maximum voluntary contraction during isometric contractions of the gastrocnemius medialis. EMGs of twelve persons were recorded with an array of four peripheral and one central electrode. Monopolar EMGs were recorded for “all-potential”, “center at current” and “all-current” conditions. Coherence revealed the similarity of signals recorded from neighboring electrodes.Coherence was high for the “all-potential”, significant for the “current at center” condition and disappeared in the “all-current” condition.It was concluded that EMG array recordings strongly depends on the measurement configuration. The proposed current amplifier significantly improves spatial resolution of EMG array recordings because the inter-electrode cross talk is reduced.  相似文献   

6.
How animals integrate different sensory information for orientation is a complex process involving interactions between a variety of internal and external factors. Due to this complexity, each component of a suite of factors is typically studied in isolation. Here, we examine how an internal factor (personality of fish) influences the response of zebrafish (Danio rerio) to the magnetic field, while swimming in a flow chamber. Our previous work demonstrated that the orientation to the water current (rheotaxis) of zebrafish individuals is influenced by variations of the magnetic field only when fish are part of a shoal. In this study, we evaluated the rheotactic behavior of 20 fish, grouped in shoals of “proactive” or “reactive” individuals, under magnetic fields of different directions. We found that the magnetic field influenced at which water speed rheotaxis was elicited in zebrafish with “reactive” personality, but not in those with “proactive” personality. These results suggest that fish personality influences response to or weighing of sensory inputs and provides some insight on the variation in behavioral responses to environmental stimuli in both laboratory and natural settings.  相似文献   

7.
The structural maintenance of chromosomes (SMC) proteins form the cores of multisubunit complexes that are required for the segregation and global organization of chromosomes in all domains of life. These proteins share a common domain structure in which N‐ and C‐ terminal regions pack against one another to form a globular ATPase domain. This “head” domain is connected to a central, globular, “hinge” or dimerization domain by a long, antiparallel coiled coil. To date, most efforts for structural characterization of SMC proteins have focused on the globular domains. Recently, however, we developed a method to map interstrand interactions in the 50‐nm coiled‐coil domain of MukB, the divergent SMC protein found in γ‐proteobacteria. Here, we apply that technique to map the structure of the Bacillus subtilis SMC (BsSMC) coiled‐coil domain. We find that, in contrast to the relatively complicated coiled‐coil domain of MukB, the BsSMC domain is nearly continuous, with only two detectable coiled‐coil interruptions. Near the middle of the domain is a break in coiled‐coil structure in which there are three more residues on the C‐terminal strand than on the N‐terminal strand. Close to the head domain, there is a second break with a significantly longer insertion on the same strand. These results provide an experience base that allows an informed interpretation of the output of coiled‐coil prediction algorithms for this family of proteins. A comparison of such predictions suggests that these coiled‐coil deviations are highly conserved across SMC types in a wide variety of organisms, including humans. Proteins 2015; 83:1027–1045. © 2015 Wiley Periodicals, Inc.  相似文献   

8.
The “mucigenic” or “muciferous” bodies of Peranema trichophorum are further characterized here as unique extrusive organelles, the mucocysts. Intracellular and ejected mucocysts have characteristic shapes that may represent different developmental stages. Mucocysts found near the Golgi apparatus are membrane-bounded, elongate, tubular structures with amorphous contents of low electron density. Subpellicular mucocysts are often aligned with pellicular striae and have dense contents, which are separated by an electron-lucent zone from granular material at the tips. Ejected mucocysts are uniform in structure and consist of an inner tube with helical striations, an outer tube with a diamond-shaped pattern, and a dense middle band. Fine fibrils, visible only after mucocyst discharge, emanate from the tips. Mucocysts may also protrude through the pellicle and discharge mucilaginous materials into the medium. Acid phosphatase activity is localized within the subpellicular mucocysts, suggesting that they may be involved in release of hydrolytic enzymes into the medium.  相似文献   

9.
A mutant of strain 69–1113a of Neurospora crassa, which shows periodic growth upon both complete and minimal media, was named “clock,” and some of the morphological and genetic differences between this mutant and the “patch” and “wild” strains were investigated. In contrast to the uniform growth of “wild,” the “clock” mutant produces a series of bands formed by cymelike aggregations of hyphae which become progressively more dense and finally mark the end (front) of a growth band. A new growth band is formed by a number of hyphae which grow out as in “wild” strains and dichotomize and form new cymes which again become progressively more dense and finally form a new front. It is shown that “clock” continues its rhythmic growth when cultured in continuous darkness. Some “wild” strains were induced to grow periodically on appropriate media. A medium containing equal quantities of sorbose and sucrose caused strain 65–811A (a “wild”) to produce the “patch” type growth. Random isolation, as well as ordered isolation, of ascospores following a cross between “wild” and “clock” show a 1: 1 segregation indicating that “clock” differs from “wild” by a single gene.  相似文献   

10.
“Permanent” or “fixed” night shifts have been argued to offer a potential benefit over rotating shift systems in that they may serve to maximize circadian adjustment and hence minimize the various health and safety problems associated with night work. For this reason, some authors have argued in favor of permanent shift systems, but their arguments assume at least a substantial, if not complete, adjustment of the circadian clock. They have emphasized the finding that the day sleeps taken between successive night shifts by permanent night workers are rather longer than those of either slowly or rapidly rotating shift workers, but this could simply reflect increased pressure for sleep. The present paper reviews the literature on the adjustment to permanent night work of the circadian rhythm in the secretion of melatonin, which is generally considered to be the best known indicator of the state of the endogenous circadian body clock. Studies of workers in “abnormal” environments, such as oil rigs and remote mining operations, were excluded, as the nature of these unique settings might serve to assist adjustment. The results of the six studies included indicate that only a very small minority (<3%) of permanent night workers evidence “complete” adjustment of their endogenous melatonin rhythm to night work, less than one in four permanent night workers evidence sufficiently “substantial” adjustment to derive any benefit from it, there is no difference between studies conducted in normal or dim lighting, and there is no evidence of gender difference in the adjustment to permanent night work. It is concluded that in normal environments, permanent night‐shift systems are unlikely to result in sufficient circadian adjustment in most individuals to benefit health and safety.  相似文献   

11.
Objective: To examine epidemiologically whether subjects with higher stress perception levels have higher leptin concentrations. Research Methods and Procedures: In this cross‐sectional study, the study population comprised 1062 male workers at local government offices in central Japan. Self‐administered questionnaires were distributed in 1997. Awareness of stress was assessed by the question: “Do you have much stress in your life?” and participants were asked to select from four possible responses: “very much,” “much,” “ordinary,” or “little.” Blood samples were also collected after fasting 12 hours overnight to determine serum leptin concentrations. Results: The mean (standard deviation) age and BMI were 50.2 (6.4) years and 23.3 (2.6) kg/m2, respectively. Crude leptin concentrations according to stress categories were 2.86, 3.26, 3.32, and 3.54 ng/mL, respectively, and leptin concentrations adjusted for age, BMI, physical activity, drinking and smoking habits, overtime work, shift work, sleep duration, and availability of confidants were 2.96, 3.24, 3.34, and 3.43 ng/mL for “little,” “ordinary,” “much,” and “very much,” respectively (p = 0.03 by one‐way analysis of covariance; p < 0.01 by test of linear trend). Significant associations were also observed among the level of perceived psychological stress and work‐related stressors, variables related to sleep, and other psychological variables. Discussion: This study showed that subjects who perceived psychological stress had high leptin levels, which provides epidemiological evidence that psychological stress may have the potential effect of increasing blood levels of the pleiotropic peptide, leptin.  相似文献   

12.
The arrangement of collagen fibers over the body surface in the basement lamella of Pseudaeris and Xenopus tadpoles is described. It can be viewed by scanning microscopy after removal of epidermis and basal lamina by trypsin treatment of alcohol fixed tissue. The orthogonal array is modified in regions where fiber direction changes extensively such as the base of the ventral fin or the posterior part of the head. In these regions “exceptional points” in the orthogonal pattern occur, as described by Rosin (1946). The pattern is bilaterally symmetrical. In the region of the nasal opening the orthogonal pattern is replaced by a mat of randomly oriented fibers. In tail regeneration the wound area is marked by aberrant disposition of collagen anteriorly then a mat of randomly disposed fibers followed posteriorly with a sharp transition to the orthogonal pattern of the regenerate. No fiber terminations could be seen in normal or regenerating regions of the lamella.  相似文献   

13.
Illicit rac‐MDPV (3,4‐methylenedioxypyrovalerone), manufactured in clandestine labs, has become widely abused for its cocaine‐like stimulant properties. It has recently been found as one of the toxic materials in the so‐called “bath salts,” producing, among other effects, psychosis and tachycardia in humans when introduced by any of the several routes of administration (e.g., intravenous, oral, etc.). The considerable toxicity of this “designer drug” probably resides in one of the enantiomers of the racemate. In order to obtain a sufficient amount of the enantiomers of rac‐MDPV to determine their activity, we improved the known synthesis of rac‐MDPV and found chemical resolving agents, (+)‐ and (–)‐2’‐bromotetranilic acid, that gave the MDPV enantiomers in >96% enantiomeric excess as determined by 1H nuclear magnetic resonance and chiral high‐performance liquid chromatography. The absolute stereochemistry of these enantiomers was determined by single‐crystal X‐ray diffraction studies. Chirality 27:287‐293, 2015. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   

14.
Sandelia bainsii is a range-restricted and highly threatened freshwater fish endemic to South Africa. Recent genetic evidence suggests that this species comprises three allopatrically distributed lineages that have been informally designated as Sandelia sp. “Kowie,” Sandelia sp. “Keiskamma” and Sandelia sp. “Buffalo.” As these lineages have only been recently identified and are likely to face a high risk of extinction because of restricted distributions, there is a critical need for generating ecological information to guide conservation prioritisation. The present study compared the historical and current distribution patterns, together with the habitat associations of Sandelia sp. “Kowie” in the Koonap and Kat rivers, tributaries of the Great Fish River. This study indicated that this lineage has been extirpated from one of the three localities in the Koonap River where it was historically abundant. In the Kat River, the current distribution of Sandelia sp. “Kowie” was comparable to its historical range, but its future persistence is threatened by the presence of non-native piscivores, instream physical barriers and potential future exploration for shale gas and infrastructure development in the Karoo Basin. A generalised hurdle negative binomial model revealed that although this lineage's probability of occurrence was high in habitats with boulder and sand substrates, and low conductivity, habitat characteristics were poor predictors of its abundance. Thus, it was postulated that the current range of this lineage probably represents the only available habitats for the persistence of different life stages for this taxon. Alternatively, the observed patterns may suggest the possibility of a shift in habitat associations, possibly for optimum utilisation of the remaining refugia within this river system. Immediate conservation measures should focus on preventing the spread on non-native invasive fishes, whereas future studies should evaluate the impacts of population fragmentation and identify appropriate intervention measures to maintain this lineage's long-term adaptive potential.  相似文献   

15.
Aggregation of the microtubule‐associated protein tau is a key feature of Alzheimer's disease and other so‐called tauopathies, yet what causes this protein to aggregate and what renders it toxic is only slowly being revealed. Because tau spreads in a stereotypical pattern through the diseased brain, it has been proposed that it possesses prion‐like properties, with aggregation‐prone tau facilitating the conversion of “naïve” tau into “toxic” forms. The current study by Wegmann et al (2015) addresses whether tau fulfils classical “prion criteria” by assessing its spreading and toxicity in the absence of endogenous tau. Using different transgenic and viral paradigms, the authors demonstrate that, although tau still propagates in this scenario, there is a decrease in its misfolding and neurotoxicity. They therefore conclude that tau is not a genuine prion, at least when the current definition of these infectious proteins is applied.  相似文献   

16.
TRPV4 is a polymodal and non-selective cation channel that is activated by multiple physical and chemical stimuli. >50 naturally occurring point-mutation of TRPV4 have been identified in human, most of which induce different diseases commonly termed as channelopathies. While, these mutations are either “gain-of-function” or “loss-of-function” in nature, the exact molecular and cellular mechanisms behind such diverse channelopathies are largely unknown. In this work, we analyze the evolutionary conservation of individual amino acids present in the lipid-water-interface (LWI) regions and the relationship of TRPV4 with membrane cholesterol. Our data suggests that the positive-negative charges and hydrophobic-hydrophilic amino acids form “specific patterns” in the LWI region which remain conserved throughout the vertebrate evolution and thus suggesting for the specific microenvironment where TRPV4 remain functional. Notably, Spondylometaphyseal Dysplasia, Kozlowski (SMDK) disease causing L596P mutation disrupts this pattern significantly at the LWI region. L596P mutant also sequesters Caveolin-1 differently, especially in partial cholesterol-depleted (~40 % reduction) conditions. L596P shows altered localization in membrane and enhanced Ca2+-influx properties in cell as well as in filopodia-like structures. We propose that conserved pattern of amino acids is an important parameter for proper localization and functions of TRPV4 in physiological conditions. These findings also offer a new paradigm to analyze the channelopathies caused by mutations in LWI regions of other channels as well.  相似文献   

17.
The scanning simulation method suggested by Meirovitch is extended to a study of the stability of decaglycine at 100 and 300 K. The model is based on the potential energy function ECEPP (Empirical Conformational Energy Program for Peptides) with rigid geometry and without solvent. The free energy of the statistical coil, which is defined over the whole phase space excluding the region of the right-handed α-helix, is calculated. At 100 K, the molecule is found to be unstable in the statistical coil region, and the method generates (i.e., “folds”) conformations that are left-handed or right-handed α-helices with very high preference. Their free energy is found to be comparable with that obtained by another method developed in our previous paper (paper I) [H. Meirovitch, M. Vásquez, and H. A. Scheraga, (1987) Biopolymers 26 , 651–671]. At 300 K the statistical coil becomes the most stable state; sample conformations of the coil are generated efficiently with the scanning method and the free energy is calculated. It appears that both the scanning method and the method of paper I can be used to carry out a complete analysis of the stability of a polypeptide based on free energy considerations.  相似文献   

18.
H Yamamoto  T Hayakawa  J T Yang 《Biopolymers》1974,13(6):1117-1125
Poly(Nδ-carbobenzoxy, Nδ-benzyl-L -ornithine) (PCBLO) was prepared by the standard NCA method. PCBLO was converted into poly(Nδ-benzyl-L -ornithine) (PBLO) through decarbobenzoxylation with hydrogen bromide. The monomer Nδ-benzyl-L -ornithine was synthesized by reacting L -ornithine with benzaldehyde, followed by hydrogenation. The conformation of the two polypeptides was studied by optical rotatory dispersion and circular dichroism. PCBLO forms a right-handed helix in helix-promoting solvents. In mixed solvents of chloroform and dichloroacetic acid (DCA) it undergoes a sharp helix–coil transition at 12% (v/v) DCA at 25°C, as compared with 36% for poly(Nδ-carbobenzoxy-L -ornithine) (PCLO). Like PCLO, the helix–coil transition is “inverse,” that is, high temperature favors the helical form. PBLO is soluble in water at pH below 7 and has a “coiled” conformation. In 88% (v/v) 1-propanol above pH (apparent) 9.6 it is completely helical. In 50% 1-propanol the transition pH (apparent) is about 7.4; this compares with a pHtr of about 10 for poly-L -ornithine in the same solvent.  相似文献   

19.
《IRBM》2021,42(6):442-456
Background and ObjectivesAt the beginning of human civilization, human being needs to undergo immense physical labor to survive. During those days high-calorie diet was essential. However, the evolution of technology has changed the scenario and much lesser amount of physical labor is required to survive in modern hi-tech days, requiring less amount of calorie. The excess calorie gets deposited in the body in the form of white fat. As a consequence, obesity appears as an epidemic all over the world. Long term obesity causes many diseases like heart attack, stroke, diabetes, and many other ailments. It is tough for people, who honestly want to check their obesity by controlling food habits, to continue a static diet chart with fixed restricted foods for a long time. Most of the time, people give up such restrictions on food. It will be very useful if a system exists, that will generate a dynamic diet chart based on calorie spend by the body.MethodsThis research describes a system that will generate a dynamic diet chart based on calorie spend by the body and other data like user's BMI, food preferences, etc. In this system, user can tailor his/her diet chart by changing daily physical activities (activities that burn calories). The main contributions of the proposed system are as follows:
  • •A dedicated hardware system to quantify physical labor during walking and running throughout the day from feet pressure changes along with walk cycle detection.
  • •The proposed hardware system can distinguish between walk and run.
  • •A dynamic diet chart preparation system, where the user has the provision to plan his/her diet chart with food affinity.
The entire work is divided into two modules; the first one focuses on the hardware design to detect and quantify physical activities during “walking” and “running”. These data are used in the second part. The second part contains calorie calculation along with the preparation of a dynamic diet chart with food affinity. In the hardware design, an Application Specific Integrated Circuit (ASIC) is proposed to measure the physical activity during “walking” and “running”.ResultAt the time of hardware logic synthesis, VHDL and FPGA are used. Experimental results show that the proposed hardware provides more accurate results than a pedometer. There is no standard metric to measure the performance of the dynamic diet chart generation system. Competency of the dietitian at the time of setting the parameters, honesty of the users at the time of the interactive session, etc. are the main factors that influence heavily the performance of the dynamic diet chart preparation system. The advantage of dynamic diet chart is that users can modify the diet menu as per their wish, and the system generates a diet chart in such a way that calorie intake (through food items) is maintained properly. In addition to this, the user can plan his future meals.DiscussionThis work is an interdisciplinary work. It is a blending of electronics (FSM), design, and computation for decision making; the computation portion includes software engineering, soft computing, etc. Future plan of this work is to integrate this system with “Cloud” to provide different data analysis related services, like region-wise food habit pattern prediction, health-related statistics, etc.  相似文献   

20.
Characterizing the nature of interaction between proteins that have not been experimentally cocrystallized requires a computational docking approach that can successfully predict the spatial conformation adopted in the complex. In this work, the Hydropathic INTeractions (HINT) force field model was used for scoring docked models in a data set of 30 high‐resolution crystallographically characterized “dry” protein–protein complexes and was shown to reliably identify native‐like models. However, most current protein–protein docking algorithms fail to explicitly account for water molecules involved in bridging interactions that mediate and stabilize the association of the protein partners, so we used HINT to illuminate the physical and chemical properties of bridging waters and account for their energetic stabilizing contributions. The HINT water Relevance metric identified the “truly” bridging waters at the 30 protein–protein interfaces and we utilized them in “solvated” docking by manually inserting them into the input files for the rigid body ZDOCK program. By accounting for these interfacial waters, a statistically significant improvement of ~24% in the average hit‐count within the top‐10 predictions the protein–protein dataset was seen, compared to standard “dry” docking. The results also show scoring improvement, with medium and high accuracy models ranking much better than incorrect ones. These improvements can be attributed to the physical presence of water molecules that alter surface properties and better represent native shape and hydropathic complementarity between interacting partners, with concomitantly more accurate native‐like structure predictions. Proteins 2014; 82:916–932. © 2013 Wiley Periodicals, Inc.  相似文献   

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