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71.
72.
Svenja Viete Walter Heiligenberg 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(1):15-23
Summary In its Jamming Avoidance Response (JAR), the gymnotiform electric fish Eigenmannia shifts its electric organ discharge (EOD) frequency away from similar interfering frequencies. Continual behavioral measurements were carried out in 164 juvenile fish until a correct JAR emerged. Sixty-four of these fish were raised in complete isolation, the remainder in a community of their siblings. A correct JAR emerged in fish of 1.2–1.6 cm in body length, corresponding to a developmental age of 24–32 days. In 6 of 164 fish, the emergence of a correct JAR followed an interim appearance of an incorrect JAR, which involved frequency shifts in the direction opposite to those of a correct JAR. The fish raised in isolation developed the same forms of behavior and showed the same sequence in their appearance as did socially raised fish. This indicates that the JAR and its developmental schedule are innate. The appearance of an incorrect JAR suggests initial errors or incompleteness in the wiring of central nervous connections. A correct JAR ultimately emerged even if a stimulus regimen was offered that rewarded frequency shifts in the direction opposite to those of a correct JAR. This indicates that the development of the JAR is immune to experimental alterations of sensory experience.Abbreviations
Df
frequency difference between a jamming stimulus and fish's EOD
-
ELL
electrosensory lateral line lobe
-
EO
electric organ
-
EOD
electric organ discharge
-
JAR
Jamming Avoidance Response
-
nE
nucleus electrosensorius
-
nE
subnucleus of nE, causing drop of EOD frequency
-
nE
subnucleus of nE, causing rise of EOD frequency
-
Pn
pacemaker nucleus
-
PPn
prepacemaker nucleus 相似文献
73.
Two population groups of Jammu and Kashmir (India) — Muslims and Bodhs-have been typed for haptoglobin and for CG and PI subtype
polymorphisms. The allele frequencies do not show significant differences between these two populations. HP and GC allele
frequencies of Bodhs and Muslims differ considerably from with that observed in other North Indian populations. The PI allele
frequencies of Bohds and Muslims differ considerably from those found in other Indian populations and are more similar to
Mongoloid ones. 相似文献
74.
R Deka A P Reddy B N Mukherjee B M Das S Banerjee M Roy B Dey K C Malhotra H Walter 《Human heredity》1988,38(5):261-266
Previous studies have reported a high incidence of hemoglobin E (HbE) in Northeast Indian populations. In the present study 10 endogamous populations of Assam belonging to two racial groups, Caucasoid and Mongoloid, were examined. The frequency of HbE gene (Hb beta E) in the Caucasoid caste populations is around 0.1, whereas the gene is highly prevalent in the Mongoloid populations, frequencies ranging between 0.2 and 0.6. Predominance of Hb beta E in the Tibeto-Burman speakers is contrary to observations made in Southeast Asia, where an association between Austro-Asiatic speakers and high prevalence of HbE exist. The highest occurrence of the gene in this area, which is on the far end of the proposed centre of distribution in Northern Kampuchea and Northeast Thailand, is also a deviation from the expected pattern of gene distribution. It is speculated that Hb beta E in the Tibeto-Burman populations of Assam arose by an independent mutation which contributed to the high frequencies of Hb beta E in the Northeast Indian populations. 相似文献
75.
H Danker-Hopfe B M Das H Walter P B Das R Das 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》1988,46(2):159-184
In 1978-79 13 Assamese populations--two Muslim groups, five Mongoloid groups and 6 Hindu caste groups--have been investigated for the distribution of anthropometric, anthroposcopic and dermatoglyphic traits as well as for the distribution of ABO blood groups and PTC taste sensitivity. Except for finger ridge patterns all traits under investigation showed a marked intergroup variability. For anthropometric, anthroposcopic and dermatoglyphic traits a clear differentiation in Mongoloid populations on one hand and Hindu caste groups on the other could be observed and be substantiated by results of corresponding distance analyses. With regard to Muslims it has to be distinguished between Marias who seem to be more closely related to Mongoloid populations and Sheikhs whose phenotypic appearance is more like that of the Hindu caste groups. The results are discussed. 相似文献
76.
77.
Putrescine-dependent S-adenosylmethionine decarboxylase (EC 4.1.1.50) was demonstrated in Ascaris suum and Onchocerca volvulus; activation was found to be about fourfold by putrescine. Mg2+ did not affect the enzyme activity. A. suum was taken as a model nematode and its S-adenosylmethionine decarboxylase was partially purified and characterized. The molecular weight was estimated to be 220,000. The apparent Km-value for adenosylmethionine was determined to be 17 microM. Methylglyoxal bis(guanylhydrazone) and berenil competitively inhibited the enzyme activity; the apparent Ki-values were found to be 0.24 microM and 0.11 microM, respectively. The dependence of filarial worms on uptake and interconversion of putrescine and polyamines as well as properties of the S-adenosylmethionine decarboxylase, different from the host enzyme, points to the polyamine metabolisms as a useful target for chemotherapy. 相似文献
78.
Gerhard Ruhenstroth-Bauer Olga Rösing Hans Baumer Walter Sönning Walter Lehmacher 《International journal of biometeorology》1988,32(3):201-204
Between the mean daily density of 28 kHz atmospherics and the onset of epileptic fits there is a highly significant correlation coefficient (r) of 0.30; there is a negative coefficient of –0.20 between the fits and the mean daily density of 10 kHz atmospherics. The onset of heart infarction is correlated with 28 kHz atmospherics (r=0.15). Furthermore, we have discovered that sudden deafness is also correlated with certain configurations of atmospherics. In this paper we report the following correlation coefficients between the inflammatory reaction of rats to a carrageenan injection (rci) into a hind paw and the mean daily pulse rate of atmospherics of the same day:r=0.49 for the 8 kHz atmospherics (P<0.02) andr=0.44 for the 10 kHz atmospherics (P<0.04). The correlations between rci reaction and other atmospherics (12 and 28 kHz) are smaller and not significant. By the method of multiple linear regression we found a multipleR=0.54 between rci reaction and the 8 and 10 kHz atmospherics (the regression function for the rci reaction is 0.15+0.004×8 kHz+0.002×10 kHz,P<0.05). 相似文献
79.
Predictive model of conjugative plasmid transfer in the rhizosphere and phyllosphere. 总被引:4,自引:3,他引:1 下载免费PDF全文
G R Knudsen M V Walter L A Porteous V J Prince J L Armstrong R J Seidler 《Applied microbiology》1988,54(2):343-347
A computer simulation model was used to predict the dynamics of survival and conjugation of Pseudomonas cepacia (carrying the transmissible recombinant plasmid R388:Tn1721) with a nonrecombinant recipient strain in simple rhizosphere and phyllosphere microcosms. Plasmid transfer rates were derived for a mass action model, and donor and recipient survival were modeled as exponential growth and decay processes or both. Rate parameters were derived from laboratory studies in which donor and recipient strains were incubated in test tubes with a peat-vermiculite solution or on excised radish or bean leaves in petri dishes. The model predicted donor, recipient, and transconjugant populations in hourly time steps. It was tested in a microcosm planted with radish seeds and inoculated with donor and recipient strains and on leaf surfaces of radish and bean plants also growing in microcosms. Bacteria were periodically enumerated on selective media over 7 to 14 days. When donor and recipient populations were 10(6) to 10(8) CFU/g (wet weight) of plant or soil, transconjugant populations of about 10(1) to 10(4) were observed after 1 day. An initial rapid increase and a subsequent decline in numbers of transconjugants in the rhizosphere and on leaf surfaces were correctly predicted. 相似文献
80.
Miconia zanonii, which occurs in broad-leaved cloud forests at four localities in the Cordillera Central of the Dominican Republic, is described
and illustrated. It is compared withM. krugii andM. samanensis, two probably close relatives withinMiconia sect.Chaenopleura. 相似文献