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1.
The elevated T-maze was combined with a free exploration protocol, which, in contrast to the conventional procedure, dispenses with handling of the animals during the experimental sessions. This allows measurement of fear indexes derived from the elevated plus-maze as well as assessment of acquisition of open arm avoidance and open arm escape in one continuous session. Retention of the different fear-responses is measured 72 h later without drug treatment. In order to assess the effects of two known anxiolytics in this paradigm, rats received an IP injection of diazepam (1 to 4 mg/kg), substance P (5 to 500 microg/kg) or vehicle (1 ml/kg) and were tested on the T-maze for 5 min. Diazepam elevated open arm activity, indicative of an anxiolytic effect. The drug also increased the latency to escape from the open arms, but did not significantly affect acquisition of open arm avoidance. During the retention trial, diazepam in higher doses impaired the performance of both fear-responses, suggestive of an anterograde amnesic effect. Substance P did not influence acquisition and retention of open arm avoidance and escape. However, in high doses, the peptide increased the sojourn time in the central arena of the maze, indicating reduced fear and, hence, a dissociation between anxiolytic and amnesic effects. The present findings demonstrate that the elevated T-maze free exploration paradigm is sensitive to anxiolytic and memory-modulating effects of drugs.  相似文献   

2.
3.
The coupled movement of tRNA-mRNA complex through the ribosome is a fundamental step during the protein elongation process. We demonstrate that the ribosome will translocate a P-site-bound tRNA(Met) with a break in the phosphodiester backbone between positions 17 and 18 in the D-loop. Crystallographic data showed that the acceptor arms of P- and E-site tRNA interact extensively with the ribosomal large subunit. Therefore, we used this fragmented P-site-bound tRNA(Met) to investigate the contributions of single 2'-hydroxyl groups in the 5' strand of the acceptor arm for translocation into the ribosomal E-site. EF-G-dependent translocation of the tRNAs was monitored using a toeprinting assay and a fluorescence-based rapid kinetic method. Surprisingly, our results show that none of the 2'-hydroxyl groups in the 5' strand of the acceptor arm of P-site-bound tRNA(Met) between positions 1-17 play a critical role during translocation. This suggests that either these 2'-hydroxyl groups are not important for translocation or they are redundant and the three-dimensional shape of the P-site tRNA is more important for translocation.  相似文献   

4.
Water-soluble carbodiimide-catalyzed cross-linking of purified cytochrome P-450 LM2, cytochrome b5, and NADPH-cytochrome P-450 reductase was used to identify stable complexes formed between these proteins. High yields of P-450-b5 and P-450 reductase-b5 dimers, and lower yields of P-450 reductase-LM2 dimers were obtained. Substitution of native b5 and P-450 reductase with fully amidinated derivatives showed that LM2 and b5 were cross-linked exclusively through their respective amino and carboxyl groups. However, there appeared to be two complexation sites on the reductase which cross-link to b5 through amino groups and to LM2 through carboxyl groups respectively. A heterotrimer could not be identified following incubation of all three proteins together with EDC.  相似文献   

5.
Susceptibility to fear and stress has often been studied in birds using selection experiments. Crosses between different species of the same genus have also been used to study the type of transmission observed for "fixed action patterns." In this experiment we used a cross between two species (male muscovy and female pekin ducks) to study the genetic transmission of various characteristics of fear reactions and adrenal activity. Males of the three genetic types (two parental species and the hybrid) were submitted to tonic immobility and fear of man tests. Blood was collected for corticosterone assay before and after physiological stress or injection of 5 microg/kg of immediate synacthen (ACTH agonist). The muscovy duck showed lower levels of fear reactions than the pekin duck in the majority of behavioral tests (six of eight). Corticosterone levels were also nearly always the lowest in muscovy ducks (five of six). Generally speaking, the muscovy duck appeared to be less fearful and less susceptible to stress than the pekin duck. The mule duck was similar to one parent, midway between the two, or showed heterosis for fear of man at 10 weeks of age (more fearful than the two parents). Corticosterone levels were midway between the two parents in the mule duck with only one exception, i.e., where the pekin duck was dominant. The existence of heterosis for fear is surprising, as this character is classically considered to be submitted to stabilizing selection. The transmission of corticosterone levels and other fear characteristics is, however, compatible with stabilizing selection. The results are discussed in terms of adaptability.  相似文献   

6.
A very mild and efficient procedure has been developed for the preparation of C-5 substituted deoxyuridines. The substituent carries a masked primary aliphatic amino group. These compounds are readily converted into their phosphoramidites and can be used to prepare oligonucleotides carrying one or more aliphatic amino groups. Fluorescein isothiocyanate coupled to these compounds gives oligonucleotide probes carrying multiple fluorescein labels. These compounds have a free 5'-hydroxy group enabling additional 5'- end radioactive labelling for evaluation of their hybridization characteristics. It was found that oligonucleotides carrying a long (11 atom) linker arm to the fluorescein hybridize more efficiently to mRNA than those carrying a short (4 atom) arm. The long linker arm derivatives are comparable to underivatized oligonucleotides in hybridizing to mRNA.  相似文献   

7.
Lee CT  Ma YL  Lee EH 《Journal of neurochemistry》2007,100(6):1531-1542
Mitogen-activated protein kinase/extracellular signal-regulated kinase plays an important role in memory formation and directly phosphorylates serum- and glucocorticoid-inducible kinase1 (SGK1) at Ser78. In this study, we examined the role and mechanism of SGK1 Ser78 activation involved in contextual fear memory formation in rats. Results revealed that SGK1 Ser78 phosphorylation was increased 30 min, 1 h and 3 h after training. Transient transfection of the dominant negative mutant of sgk, sgkS78A, to hippocampal neurons impaired, whereas transfection of the constitutively active sgk, sgkS78D, enhanced fear retention. Microarray analysis identified 14 genes that showed more than threefold alteration in their gene expression in sgkS78A-transfected animals 6 h after training. One of them is Hairy and Enhancer of split 5 (Hes5). The expression level of Hes5 is approximately 4.4-fold higher in sgkS78A-transfected animals. Further analyses revealed that Hes5 level is markedly decreased after training in control animals, but sgkS78A markedly increased Hes5 level after training. RNA interference experiment showed that shHes5 dose-dependently enhanced fear retention, whereas over-expression of Hes5 impaired fear retention. Moreover, shHes5 at a lower concentration completely blocked the memory-impairing effect of sgkS78A. These results together suggest that Hes5 negatively regulates contextual fear memory formation and SGK activation down-regulates Hes5 expression to enhance fear retention.  相似文献   

8.
Receptors for insulin, low-density lipoprotein, and colony stimulating factor 1 are associated with diabetes, atherosclerosis, and cancer in man. Complementary DNA clones for Insr, Ldlr, and Csfmr were used to chromosomally assign the three genes in mouse. In contrast to their close linkage on the short arm of human Chromosome 19, Insr and Ldlr are asyntenic, residing on mouse Chromosomes 8 and 9, respectively. The genes for CSF1R, CSF1, CSF2, IL-3, and IL-5 form a cluster on the long arm of human Chromosome 5. In mouse, Csfm, Csfgm, and IL-3 are syntenic on Chromosome 11. The Csfmr gene was assigned to mouse Chromosome 18 and is thus unlinked to other members of this gene cluster. These gene assignments provide additional topographical information on conservation of linkage groups in man and mouse and provide a genetic framework for evaluating the possible roles for the three receptor genes in genetic diseases in mouse.  相似文献   

9.
The meiotic behaviour of chromosomes 1R, 2R and 5R was studied in C-banded preparations of autotetraploid rye. Analysis of pairing and chiasma formation was based on metaphase I configurations, using the model designed by Sybenga, with slight modifications. Frequencies of two modes of pairing (one quadrivalent or two bivalents) differed from those expected for random pairing. Although preferential pairing for some arm pairs of chromosome 2R was detected, this did not seem to be the cause of the increased bivalent pairing. This increase was attributed to either the spatial separation of the four homologous chromosomes in some premeiotic cells into two groups of two, or a correction of the synaptonemal complex, or both. The number of chiasmate associations showed variation between chromosomes and between arms within the same chromosome. It was closely related to arm length, but different after quadrivalent and bivalent pairing. This is suggested to be a consequence of partner exchange interfering with pairing and, consequently, with chiasma formation, and a different chiasma distribution after quadrivalent pairing. Variation between chromosomes in the frequencies of alternate and adjacent co-orientation in metaphase I quadrivalents without interstitial chiasmata suggests that the relative positions of the centromeres in the quadrivalent influence their co-orientation.  相似文献   

10.
The 5S rDNA locus on the long arm of barley chromosome 2(2H) was genetically mapped in two crosses in relation to 30 other RFLP loci. Comparison of the genetic maps with the previously published physical position of the 5S rDNA, determined by in-situ hybridization, showed that there was a marked discrepancy between physical and genetic distance in both crosses, with recombination being less frequent in the proximal part of the arm. Pooled information from the present study and other published genetic maps showed that at least 26 of the 44 (59%) RFLPs that have been mapped on 2(2H)L lie distal to the 5S rDNA locus even though this region is only 27% of the physical length of the arm. The distribution of RFLP markers is significantly different from expected (P < 0.01), implying that the low-copy sequences used for RFLP analysis occur more frequently in distal regions of the arm and, or, that sequences in distal regions are more polymorphic.  相似文献   

11.
Genetic selection on a single fear test, the tonic immobility test, seems to result in selection on fearfulness, i.e. the propensity to exhibit fear responses, whatever the fear tests used. However, the conception of fear as a single variable has been challenged by the recognition that fear is multidimensional. This study was designed to test whether genetic selection on a classic index of fear in birds, tonic immobility duration, is accompanied by changes in the response to a single dimension of fear – novelty.Two lines of quail divergently selected for long (LTI) or short (STI) duration of tonic immobility were exposed to a novel object in their home cage. Quail of both lines showed typical fear reactions in response to novelty but there was no difference between lines. We conclude that genetic selection for tonic immobility duration does not affect all dimensions of fear, notably not novelty. Further studies are needed to investigate the dimensions of fear on which the two lines of quail could have been selected.  相似文献   

12.
R N Sarma  L Fish  B S Gill  J W Snape 《Génome》2000,43(1):191-198
The wheat homoeologous Group 5 chromosomes were characterized physically in terms of rice linkage blocks using a deletion mapping approach. All three chromosomes, 5A, 5B, and 5D, were shown to have a similar structure, apart from the 4A-5A translocation on the distal end of chromosome arm 5AL. The physical mapping of rice markers on the deletion lines revealed that the whole of rice chromosome 9 is syntenous to a large block, proximal to the centromere, on the long arm. Likewise, a small segment of the distal end of the long arm showed conserved synteny with the distal one-third end of the long arm of rice chromosome 3. In between those conserved regions, there is a region on the long arm of the Group 5 chromosomes which shows broken synteny. The proximal part of the short arms of the Group 5 chromosomes showed conserved synteny with a segment of the short arm of rice chromosome 11 and the distal ends showed conserved synteny with a segment of rice chromosome 12. The physical locations of flowering time genes (Vrn and earliness per se) and the gene for grain hardness (Ha) on the Group 5 chromosomes were determined. These results indicate that comparative mapping using the deletion mapping approach is useful in the study of genome relationships, the physical location of genes, and can determine the appropriate gene cloning strategy.  相似文献   

13.
Social isolation of rodents during development is thought to be a relevant model of early-life chronic stress. We investigated the effects of early-life social isolation on later adult fear and anxiety behavior, and on corticosterone stress responses, in male rats. On postnatal day 21, male rats were either housed in isolation or in groups of 3 for a 3 week period, after which, all rats were group-reared for an additional 2 weeks. After the 5-week treatment, adult rats were examined for conditioned fear, open field anxiety-like behavior, social interaction behavior and corticosterone responses to restraint stress. Isolates exhibited increased anxiety-like behaviors in a brightly-lit open field during the first 10 min of the test period compared to group-reared rats. Isolation-reared rats also showed increased fear behavior and reduced social contact in a social interaction test, and a transient increase in fear behavior to a conditioned stimulus that predicted foot-shock. Isolation-reared rats showed similar restraint-induced increases in plasma corticosterone as group-reared controls, but plasma corticosterone levels 2 h after restraint were significantly lower than pre-stress levels in isolates. Overall, this study shows that isolation restricted to an early part of development increases anxiety-like and fear behaviors in adulthood, and also results in depressed levels of plasma corticosterone following restraint stress.  相似文献   

14.
Bacterial sulfate reduction activity (SRA) was measured in surface sediments and slurries from three sites in the Great Salt Lake (Utah, USA) using radiolabeled 35S-sulfate. High rates of sulfate reduction (363 ± 103 and 6,131 ± 835 nmol cm-3 d-1) were measured at two sites in the moderately hypersaline southern arm of the lake, whereas significantly lower rates (32 ± 9 nmol cm-3 d-1) were measured in the extremely hypersaline northern arm. Bacterial sulfate reduction was strongly affected by salinity and showed an optimum around 5-6% NaCl in the southern arm and an optimum of around 12% NaCl in the more hypersaline northern arm of the lake. High densities of sulfate-reducing bacteria (SRB) ranging from 2.2 × 107 to 6.7 × 108 cells cm-3 were determined by a newly developed tracer MPN-technique (T-MPN) employing sediment media and 35S-sulfate. Calculation of specific sulfate reduction rates yielded values comparable to those obtained in pure cultures of SRB. However, when using a conventional MPN technique with synthetic media containing high amounts of Fe(II), the numbers of SRB were underestimated by 1-4 orders of magnitude as compared to the T-MPN method. Our results suggest that high densities of slightly to moderately halophilic and extremely halotolerant SRB are responsible for the high rates of sulfate reduction measured in Great Salt Lake sediments.  相似文献   

15.
The effects of socioeconomic differences on the nutritional status of two groups of urban living children are considered via an anthropometric assessment of body composition. The sample consists of 981 Guatemala City children, 7.00 to 13.99 years old, of high and low socioeconomic status (SES). High SES children have larger median values for triceps skinfold, subscapular skinfold, arm circumference, and estimated mid-arm muscle and fat areas than low SES children. Compared with children of a US reference sample, the high SES children generally have larger values for all variables and the low SES children have smaller values. However, the differences between the low SES children and the children of the other two samples are greater for arm fat area than for arm muscle area. The analysis suggests that low SES Guatemalan children suffer to a greater extent from chronic energy, rather than protein, undernutrition. A similar pattern of energy malnutrition has been observed for rural Guatemalan children. These combined data suggest that estimates of fat reserves of the arm provide a useful indication of nutritional status for Third-World children. Results from rural Costa Rican and Honduran studies have been taken to mean that muscle reserves are better than fat reserves as indicators of nutritional status in developing countries. But, those studies did not estimate cross-sectional muscle and fat areas and only considered the extremes of the population distribution for muscle and fat.  相似文献   

16.
Hormones highly influence female behaviors. However, research on this topic has not usually considered the variable hormonal status. The prelimbic cortex (PrL) is commonly engaged in fear learning. Connections from and to this region are known to be critical in regulating anxiety, in which serotonin (5-HT) plays a fundamental role, particularly through changes in 5-HT1A receptors functioning. Also, hormone fluctuations can greatly influence anxiety in humans and anxiety-related behavior in rodents, and this influence involves the functioning of 5-HT brain systems. The present investigation sought to determine whether fluctuations in ovarian hormones relative to the estrous cycle would influence the expression of learned fear in female rats previously selected as low- (LA) or high-anxious (HA). Furthermore, we investigate the role of the 5-HT system of the PrL, particularly the 5-HT1A receptors, as a possible modulator of estrous cycle influence on the expression of learned fear through intra-PrL microinjections of 5-HT itself or the full 5-HT1A agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamine)tetralin). Behavioral changes were assessed using the fear-potentiated startle (FPS) procedure. The results showed that fear intensity is associated with hormonal decay, being more accentuated during the estrus phase. This increase in fear levels was found to be negatively correlated with the expression of potentiated startle. In rats prone to anxiety and tested during the proestrus and estrus phases, 5-HT mechanisms of the PrL seem to play a regulatory role in the expression of learned fear. These results were not replicated in the LA rats. Similar but less intense results were found regarding the early and late diestrus. Our data indicate that future studies on this subject need to take into account the dissociation between low- and high-responsive females to understand how hormones affect emotional behavior.  相似文献   

17.
The aim of this project was to investigate dental anxiety and its expression in utilisation of dental services, oral health and oral symptoms. In a cross-sectional study of women's health in Göteborg (population 432,000), Sweden, 1016 women aged 38 to 84 years participated. This randomly selected population took part in a series of investigative procedures including medical and dental clinical examinations, interviews and questionnaires. Levels of dental anxiety were measured on the Corah Dental Anxiety Scale (DAS). The average DAS score obtained was 7.2. The study showed that older women were significantly less anxious than younger ones. Severe dental anxiety (DAS 15) was experienced by 3.9% of the participants. This frequency corresponds well with findings by Hällström and Halling in their analysis of data from the first Göteborg study of women's health 24 years ago. High levels of dental anxiety were correlated with longer intervals between dental visits, poorer oral function and aesthetics and a higher frequency of oral symptoms. Headaches were more prevalent in the younger age groups and a correlation with dental anxiety was revealed. Our previous studies have shown that symptoms such as tension headaches are prevalent among dental phobic patients and that they are reported to be reduced by therapy for dental fear. The clinical and radiographical examinations revealed a generally poorer oral status, with a statistically significant higher number of decayed teeth among women with high dental anxiety.  相似文献   

18.
The present study aimed to reveal the effect of fasting (21 days) on collective movement and interaction dynamics in both homogeneous (eight members fed a commercial diet or deprived of food) and heterogeneous (four fed + four starved members) shoals of juvenile qingbo (Spinibarbus sinensis). The authors of this study measured the shoaling behaviour in both a commonly used rectangular open arena with no spatial complexity and a radial arm maze. When measured in the open arena, the starved shoals had a faster swimming speed and acceleration rate and a longer interindividual distance than the fed shoals, possibly because of the elevated foraging motivation. Nonetheless, the values of the heterogeneous groups were similar to those of the fed groups. Furthermore, in contrast to the fish in homogeneous shoals, the starved fish in heterogeneous shoals showed a slower acceleration rate and speed than fed members in heterogeneous shoals. These results, combined with the relationships of variables at the among- and within-shoal levels, suggested that starved fish limited their motion in heterogeneous shoals to maintain group cohesion but that the fed fish contributed more to maintaining shoal structure, possibly because of the higher energy expenditure required for movement changes. When monitored in a radial arm maze, starved shoals showed more fission–fusion episodes without sacrificing group cohesion, as they adaptively adjusted the frequency and duration of each majority choice. The among-shoal variation revealed that the heterogeneous groups showed less variation in the open arena but more variation in the radius maze than did the homogeneous groups. This difference might arise because dominant members have opposite effects on shoal behaviour and consensus decisions. In conclusion, the present study showed opposite effects of feeding states on collective behaviour between homogeneous and heterogeneous shoals, possibly because of the complicated interactions among members with different energy storage levels and foraging motivations. Furthermore, the heterogeneous groups showed a difference between shoal behaviour in the open area and exploration in the radial arm maze. Future studies manipulating the personality composition of starved and fed members of heterogeneous groups might yield interesting results.  相似文献   

19.
The aim of this research was to investigate the opinions and attitudes of medical staff towards schizophrenic patients. The research included three groups of examinees, 200 physicians of various specialties, 200 nurses and technicians working in Zagreb city hospitals, and 200 3rd and 4th year students of the School of Medicine in Zagreb. Previously validated anti-stigma questionnaire was used, consisting of 25 questions divided into three thematic groups, structured and adapted to the specific requirements of this study. The results were mutually compared and statistically analyzed by applying the chi 2-test. Significant difference (p < 0.01) between the answers of physicians and those of medical students was found in questions 2, 4, 5, 6, 11, 13, 15, 16, 18, 22, 23, 25, and between physicians and nurses/technicians in answers to questions 4, 15, 22, 23. Significant difference (p < 0.01) between the answers given by nurses/technicians and medical students was found in questions 10, 13, 22, 23. The results point to the existence of prejudices and stigmatizing attitudes in all three investigated groups. The most frequent reasons for stigmatizing attitude of students are based on fear and insufficient knowledge about mental patients and schizophrenia as a disease, while there are a high percentage of positive answers to the questions on rehabilitation and resocialization. The nurses/technicians also show a high degree of mistrust towards schizophrenic patients and mostly answer with "I don't know", thus presenting insufficiently formed attitudes about the mentioned problems. The physicians in their answers confirm fear, mistrust and stigmatizing attitudes towards schizophrenic patients found in general population in Croatia. The consequences of such attitudes are the low quality of life of schizophrenic patients, and slow, often incomplete, resocialization.  相似文献   

20.
Mean values and standard deviations of total body volume, body density, arm volume, height, weight and a battery of 15 measurements of arm comprising different lengths, girths, diameters and skinfolds of 200 Punjabi girls aged 10–19 years are presented. Relationship between arm volume and total body volume in different age groups are also studied. Highly significant and positive correlations existed between arm volume and total body volume and the values of correlation coefficients r ranged between 0.78 to 0.92 in different age groups. Body volume was estimated also from arm measurements by using selective stepwise multiple linear regression analysis for each age group. Highly significant multiple correlation coefficients R were obtained for predicting total body volume from arm measurements and the values of multiple R ranged between 0.92 to 0.97 in different age groups even with a combination of just three or four arm measurements. The most commonly selected measurements up to fourth step in most of the age groups were upper arm girth and maximum forearm girth.  相似文献   

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