The checkerboard score and species distributions

Summary There has been an ongoing controversy over how to decide whether the distribution of species is random — i.e., whether it is not greatly different from what it would be if species did not interact. We recently showed (Roberts and Stone (1990)) that in the case of the Vanuatu (formerly New Hebrides) avifauna, the number of islands shared by species pairs was incompatible with a random null hypothesis. However, it was difficult to determine the causes or direction of the community's exceptionality. In this paper, the latter problem is examined further. We use Diamond's (1975) notion of checkerboard distributions (originally developed as an indicator of competition) and construct a C-score statistic which quantifies checkerboardedness. This statistic is based on the way two species might colonise a pair of islands; whenever each species colonises a different island this adds 1 to the C-score. Following Connor and Simberloff (1979) we generate a control group of random colonisation patterns (matrices), and use the C-score to determine their checkerboard characteristics. As an alternative mode of enquiry, we make slight alterations to the observed data, repeating this process many times so as to obtain another control group. In both cases, when we compare the observed data for the Vanuatu avifauna and the Antillean bat communities with that given by their respective control group, we find that these communities have significantly large checkerboard distributions, making implausible the hypothesis that their species distributions are a product of random colonisation.     

Genetic Determination of Mental Activity Parameters in the Families of Schizophrenia Patients

Psychological parameters of mental activity (30 in total) and their genetic determination were studied in 67 families of schizophrenia patients (67 patients, 107 parent, and 30 sibs). Abnormalities of most of the examined characteristics were found in both the patients and their healthy relatives. Parameters of attention shifting and emotionality revealed the largest genetic component (25–75 and 17–98%, respectively) in all analyzed groups of relatives (probands–affected sibs, probands–healthy sibs, healthy parents–healthy children, affected parents–affected children). Significant impact of genetic factors was also found in parameters stability of attention under conditions of continuous concentration, mediated retention span productivity of voluntary retention by reproduction data, personal anxiety level, reflection of unusual social groups, and self-assessment. The relationships among the characteristics examined in the system of mental activity were established by means of cluster analysis. The results of this study can be used in medical genetic counseling for identifying subjects at high risk for schizophrenia.     

The effect of leaf source and developmental stage on shoot organogenic potential of sweetgum (Liquidambar styraciflua L.) leaf explants

Leaf explants harvested from shoot proliferating cultures and intact plants of Liquidambar styraciflua Variegata were placed on solidified Woody Plant medium supplemented with 0.1 mgl^-1 (0.5 M) naphthaleneacetic acid and 2.5 mgl^-1 (11.1 M) benzyladenine to initiate shoot meristems directly. Leaves from intact plants produced over 4 times more adventitious shoots than leaves from in vitro shoots and had a greater tendency to form shoots on the lamina. The relative developmental age of leaf tissue used dramatically influenced the shoot organogenic response observed for leaf explants from intact plants of L. styraciflua Variegata and Moraine.-Leaves that were either 20% or 50% of full size and still actively expanding were superior to other developmental stages for shoot organogenesis. As developmental leaf age increased throughout the period of leaf expansion, the number of shoots forming on the petiole stub remained constant, whereas shoot formation on the lamina increased 8 fold. Shoots derived from Variegata leaves rooted well and grew normally as plants. Differences in rooting ability and plant size could be detected between groups that had been separated according to explant source (in vitro vs. intact plant) and the location of shoot formation (petiole vs. lamina).     

Molecular dynamics simulation of crystalline β-cyclodextrin dodecahydrate at 293 K and 120 K

Molecular dynamics (MD) simulations for crystalline -cyclodextrin dodecahydrate (-CD) at two different temperatures, 293 K and 120 K, have been performed using the GROMOS program package. The calculated structural properties are compared to those obtained from neutron diffraction studies of this system at the quoted temperatures. The simulation was carried out over a period of 20 ps on four unit cells containing 8 -CD molecules and 96 water molecules, whereby all atoms were allowed to move.At room temperature, the experimental positions of the (non-hydrogen) glucose atoms are reproduced within 0.034 nm, a value which is smaller than the experimental (0.041 nm) or simulated (0.049 nm) overall root mean square (rms) positional fluctuation. The corresponding numbers for the low temperature study are 0.046 nm, 0.019 nm and 0.022 nm. At both temperatures the experimentally observed degree of anisotropy of the atomic motions is also found in the simulations.The comparison of a variety of structural properties leads to the conclusion that the molecular model and force field used are able to simulate the cyclodextrin system very well. Experimentally observed differences in properties as a function of number of glucose units in the CD molecule (-CD, 6 versus -CD, 7) and as a function of temperature are qualitatively reproduced by the simulations.     

Zur Biogeographie des Südwestatlantik mit besonderer Berücksichtigung der Seeanemonen (Coelenterata: Actiniaria)

Extensive sampling of benthos by F.R.V. Walther Herwig (1966, 1970/71, 1978) covering the continental shelf of Argentina yielded some 1000 sea anemone specimens (19 species). The distribution patterns of the sublittoral and archibenthal species are analysed and compared with the rather scanty and controversial hydrographical information available. Species with discontinuous distribution along the continental shelf edge are believed to indicate discontinuous yet relatively stable oceanographic conditions within the depth concerned. The archibenthal Challenger Terrace, located immediately near and beneath the subtropical convergence, harbours a peculiar faunal assemblage of partly subantarctic/antarctic character and partly consisting of species which seem to be typical for permanent hydrographic fronts. In addition, the study includes a new taxonomic combination:Bolocera tuediae subsp.kerguelensis (Studer, 1879) nov. comb.

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Ergebnisse der Forschungsreisen des FFS Walther Herwig nach Südamerika Nr. 66

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Mitglied der Taxonomischen Arbeitsgruppe     

The solution structure of the human retinoic acid receptor-β DNA-binding domain

Summary The three-dimensional structure of the DNA-binding domain of the human retinoic acid receptor- (hRAR-) has been determined by nuclear magnetic resonance spectroscopy in conjunction with distance geometry, restrained molecular dynamics and iterative relaxation matrix calculations. A total of 1244 distance restraints were obtained from NOE intensities, of which 448 were intra-residue and 796 inter-residue restraints. In addition 23 and 30 dihedral angle restraints were obtained from J-coupling data. The two zinc-finger regions of the 80-amino acid residue protein are followed by two -helices that cross each other perpendicularly. There is a short stretch of b-sheet near the N-terminus. The -helical core of the protein is well determined with a backbone root-mean-square deviation (r.m.s.d.) with respect to the average of 0.18 Å and 0.37 Å when the side chains of residues 31, 32, 36, 61, 62, 65 and 69 are included. The r.m.s.d. for the backbone of residues 5–80 is 0.76 Å. For the first finger (residues 8–28), the r.m.s.d. of the backbone is 0.79 Å. For the second finger (residues 44–62) the r.m.s.d. is 0.64 Å. The overall structure is similar to that of the corresponding domain of the glucocorticoid receptor, although the C-terminal part of the protein is different. The second -helix is two residues shorter and is followed by a well-defined region of extended backbone structure.     

Erythromycin, lincosamides, peptidyl-tRNA dissociation, and ribosome editing

Inaccurate protein synthesis produces unstable -galactosidase, whose activity is rapidly lost at high temperature. Erythromycin, lincomycin, clindamycin, and celesticetin were shown to counteract the error-inducing effects of streptomycin on -galactosidase synthesized in the antibiotic-hypersensitive Escherichia coli strain DB-11 Met ^–. Newly synthesized -galactosidase was more easily inactivated by high temperatures when synthesized by bacteria partially starved for arginine, threonine, or methionine. Simultaneous treatment with erythromycin or linocomycin yielded -galactosidase that was inactivated by high temperatures less easily than during starvation alone, an effect attributed to stimulation of ribosome editing. When synthesized in the presence of canavanine, -galactosidase was inactivated by high temperature more easily but this effect could not be reversed by erythromycin. The first arginine in -galactosidase occurs at residue 13, so the effect of erythromycin during arginine starvation is probably to stimulate dissociation of erroneous peptidyl-tRNAs of at least that length. Correction of errors induced by methionine starvation is probably due to stimulation of dissociation of erroneous peptidyl-tRNAs bearing peptides at least 92 residues in length. All the effects of erythromycin or the tested lincosamides on protein synthesis are probably the result of stimulating the dissociation from ribosomes of peptidyl-tRNAs that are erroneous or short.     

Elternschaftsnachweise bei Trauerschn?ppernFicedula hypoleuca am Westrand ihres mitteleurop?ischen Verbreitungsareals

Zusammenfassung Bei Lingen/Emsland (52.27° N, 7.15° E) in Norddeutschland wurden 31 Trauerschnäpperbruten mit Hilfe des Oligonukleotid DNA-Fingerprintings untersucht. In 4 Bruten (12,9 %) fanden sich insgesamt 9 Nestlinge, die auf Fremdkopulationen der zurückgingen. Ihr Anteil an der Gesamtzahl der Nestlinge (n=165) betrug 5,5 %. Bezieht man den Verpaarungsstatus der in die Betrachtungen ein, findet sich ein signifikanter Unterschied: Nur eines von 20 anscheinend monogam verpaarten wurde betrogen, dagegen fanden sich bei nicht weniger als 3 von 7 bigyn verpaarten Nestlinge, die auf Fremdkopulationen der zurückgingen. Der Anteil betrogener bigyner wird dabei unter Umständen sogar unterschätzt, da in drei Fällen die Primärbruten nicht untersucht werden konnten.

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Parentage analyses in the Pied FlycatcherFicedula hypoleuca at the western boundary of its Central European range

The study deals with the occurrence of extra-pair copulations within a Pied Flycatcher population near Lingen/Emsland (52.27° N, 7.15 ° E) in northern Germany. As a whole, 31 Pied Flycatcher broods were investigated using oligonucleotide DNA finger-printing. In 4 broods (12.9 %) a sum of 9 nestlings were found to be due to extra-pair copulations of the females. Their proportion with regard to the total number of nestlings investigated (n=165) amounts to 5.5 %. Integrating the pairing status of males into the analyses a significant difference was found: Only one of 20 obviously monogamous males was cuckolded, while for 3 of 7 bigyneous males' nestlings were identified that resulted from extra-pair copulations of the females. The proportion of cuckolded bigyneous males may be even underestimated, because in three cases the primary broods could not be investigated.

     

Origin of the genetic code and specificity of tRNA aminoacylation. A testable model

Conclusion The specificity of tRNA aminoacylation as well as the origin of the genetic code are far from being understood at the molecular and evolutionnary level. The tRNA-tRNA interaction model could provide a missing link for resolving both problems. The model suggests a direct chemical interaction between the nucleotides in the anticodon, and the amino acid (adenylate) to be transferred to the 3-terminal adenosine, within the catalytic center (23). The experimental data reviewed here indicate that in many, but not all, systems the anticodon does play a major role during the aminoacylation and that the simultaneous binding of two tRNA molecules for aminoacylation (of only one of them) does not contradict enzymatic and crystallographic data (24).     

Methodological problems in evolutionary biology VIII. Biology and culture

Biology cannot accommodate all aspects of culture. Aspects of culture that a biological approach can take into account can be covered by the biological categories of phenotype and environment. There is no need to treat culture as a separate category. Attempts to elaborate biological explanations of cultural variation will meet with success only if biologists expand theories of development, and integrate them in evolutionary biology. The alternative — elaborating the idea of so-called cultural inheritance — makes little sense from a biological point of view.     

Morocco as a possible domestication center for barley: biochemical and agromorphological evidence

Summary The distribution of genetic variants of a group of low molecular weight, chloroform-methanol soluble proteins (CM proteins), among Moroccan and non-Moroccan accessions of Hordeum spontaneum and among selections from several Moroccan landraces of H. vulgare and cultivars of the same species with widespread European origin, suggests that domestication of barley might have taken place in Morocco. An agromorphological characterization of the H. spontaneum accessions further supports this hypothesis. The possible Moroccan origin of the French cultivar Hatif de Grignon and of several Spanish 6-rowed barleys is also presented.     

Composition and structure of aquatic organism communities in various water conditions of a paddy field

The purpose of this study was to clarify the differences of the community structure and the diversity of aquatic organisms (i) among sampling sites that the distances from inlets or outlets were different each other, and (ii) between the floodwater and the irrigation water during the crop season in a paddy field. The irrigation water was sampled from one inlet. The taxonomical groups and the number of aquatic organisms ranging in size from 30µm to 2cm in the floodwater and the irrigation water were surveyed approximately every 10days during the growth period of the rice plant. Aquatic organisms were classified mainly at the order level. Thirty-eight taxonomical groups of aquatic organisms were found in the floodwater, while 18 groups were found in the irrigation water. We were not able to find the differences of the community structure of aquatic organisms among the sites. In the floodwater, the number of taxonomical group increased and the community structure changed during the late flooding period (over 50days after the onset of flooding) at any site, while those in the irrigation water hardly changed. Although the community structure of aquatic organisms differed between the floodwater and the irrigation water throughout the flooding period, the differences became especially bigger during the late flooding period. Principal component analysis showed that three groups (Pennales, Dinoflagellida, Choreotrichida) characterized the community structure in the irrigation water. Their population densities tended to be the highest at the site near inlets and the lowest at the site far from inlets.     

Selection for rate of development and pupal weight in ‘Cnephasia’ jactatana: A genetic tool for quality improvement

Selection for fast and slow rate of pupation over three successive generations in Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) produced a fast strain that pupated 2 days earlier than the slow strain. Selection for pupal weight was asymmetrical with the light selection having more effect than the heavy selection. The larval critical weight (L_CW), the larval maximum weight (L_MW) and the latent feeding period were not affected by any of the selections. Slow and light selections resulted in longer pre-pupal periods than fast, heavy or the laboratory population. Fecundity was reduced in females from slow and light selections. Selection in insects is discussed as a possible genetic tool for overall quality improvement.Résumé La sélection pour la rapidité d'apparition des chrysalides de C. jactatana Walker produit en 3 générations une lignée rapide qui se nymphose 2 jours avant la lente. La sélection pour le poids des chrysalides est asymétrique, ayant plus d'effet sur la sélection développement lent que sur la sélection développement rapide. Le poids critique larvaire (L_CW), le poids larvaire maximal (L_MW) et la période latente d'alimentation ne sont pas modifiés par ces sélections. Les lignées lente et légère ont des périodes prénymphales plus longues que les lignées rapide et lourde, ou la souche de laboratoire. Les fécondités des lignées lente et légère sont réduites. Les sélections associées des insectes sont examinées comme outil génétique potentiel permettant d'améliorer les performances globales.     

Ritual,the state,and the transformation of emotional discourse in Iranian society

This paper explores the social and cultural organization of Iranian emotional discourse and its transformation in post-revolutionary Iran. First, the Moharram dramas we participated in during field research are described, indicating how these performances organized a prototypical view of the social order, the self, and the passions. Using Kapferer's distinction between transcendental and transformative rituals, we argue that these dramas were traditionally organized as transcendental rites. Second, data on grieving rituals and depressive illness among Iranians is introduced, focusing on the transformative qualities of mourning rites and suggesting an interpretation of depression as a failure of the work of culture. Third, the appropriation of these symbolic forms of society, self, and the emotions by the current Iranian Islamic state and the role of the state in defming the meaning and legitimacy of emotions and their expression is analyzed.     

Photosensitization and the nervous system in the planarian Dugesia gonocephala

Summary Photosensitization phenomena may be induced in planarias by eosin and hematoporphyrin, and as a result, dopamine agonistic behavior (screw-like hyperkinesia) is set up in the animal. Histochemical, ultrastructural and pharmacological investigations have shown that this hyperkinesia is of postsynaptic origin in eosin photosensitization, and of pre-synaptic origin in hematoporphyrin photosensitization. The authors suggest an hypothesis to explain the different activity of the two photosensitizers, and discuss the validity of the experiment with regard to human porphyria.     

The physiological ecology of two populations of Mytilus edulis L.

Summary Seasonal cycles in the rates of oxygen consumption, feeding, absorption efficiency and ammonia-nitrogen excretion in two populations of Mytilus edulis were measured in the field under ambient conditions and related to body size, the gametogenic cycle, the concentration of suspended particulate matter in the water and temperature. Relationships between the various physiological variables are also considered and protein and energy budgets estimated. Both the scope for growth and the relative maintenance cost were seasonally variable, demonstrating a minimum capacity for growth in the winter and a maximum capacity in the summer. In one population subjected to abnormally high temperatures in the winter the scope for growth was negative for four or five months between January and May. These population differences are discussed and the potential for using physiological integrations in intra-specific comparisons of fitness is identified.     

A linear spatio-temporal model of the light-to-bipolar cell system and its response characteristics to moving bars

A linear spatio-temporal model for the visual pathway from receptor to bipolar cell is presented. This model is based on histological and electrophysiological data obtained from previously published work. The model incorporates the salient linear spatio-temporal dynamic characteristics of the light-to-bipolar cell system, and aims at furthering our understanding of the integrated spatio-temporal response characteristics of this system. This model is used to examine the way spatial and temporal dynamic characteristics combine to form the response of a single bipolar and of a combination of two bipolars to a moving bar stimulus. A unimodal speed sensitivity curve is identified than can be used to postulate speed detection schemes based on simple thresholding operations. The dependence of this speed sensitivity curve on specific temporal and spatial parameters of the receptive field is studied, giving rise to some simple speed discrimination schemata.Dr. Curlander is currently with the Jet Propulsion Laboratory of the California Institute of Technology, Pasadena, CA91109, USA     

The semantics of pain in Indian culture and medicine

An interpretive perspective offers a counterpoint to the behavioral orientation in the social scientific literature on pain. The present paper develops a meaning-centered approach which focuses on three interconnected aspects of the experience of suffering: (l) the cultural construction of pain sensation; (2) the semiotics of pain expression; (3) the structure of pain's causes and cures. These connections are explored through a variety of linguistic and semiotic forms, including metaphors, etymologies, gestural codes, taxonomies, and semantic networks. The study of metaphor has special value in revealing the cultural construction of pain, especially its sensory qualities, such as temperature, weight, and movement. The concept of semantic network provides a complementary tool for understanding pain experience; the analysis makes pain sensation the center of the network and argues that multiple meanings attach to this sensory core.The paper examines these perspectives in the context of North Indian culture and medicine, specifically Unani Tibb, or Greco-Arab medicine. Pursuing questions of the fit between everyday belief and traditional medicine, the essay traces continuities in the language of pain in North Indian culture, classical Unani Tibb, and contemporary Unani clinical practice.[/ p]My research on Unani medicine in India was funded by a Senior Fellowship from the Shastri Indo-Canadian Institute from January to August 1983. An earlier version of this paper was prepared for the Ninth European Conference on Modern South Asian Studies, Heidelberg University, July 9–12, 1986, for a panel organized by Dr. Beatrix Pfleiderer on The Cultural Context of Health Care in South Asia. I am grateful to Dr. Patricia Jeffery of the University of Edinburgh for presenting the paper for me. I would like to thank Mohammed Sultan Yar Khan and his family, Hakim Mohammed Razzack and Hakim Umul Fazl of the Central Council for Research in Unani Medicine, and Hakim Abdul Hameed of the Institute for History of Medicine and Medical Research, for their aid and advice in India. I would also like to acknowledge Arthur Kleinman for his comments on the paper, and Vandana Goswami, Vasavi Gowda, and Khalida Zaki for our discussions about pain in South Asia.     

On the eigenvalue distribution of genetic and phenotypic dispersion matrices: Evidence for a nonrandom organization of quantitative character variation

A quantitative genetic model of random pleiotropy is introduced as reference model for detecting the kind and degree of organization in quantitative genetic variation. In this model the genetic dispersion matrix takes the form of G = BB ^T, where B is a general, real, Gaussian random matrix. The eigenvalue density of the corresponding ensemble of random matrices (_G) is considered. The first two moments are derived for variance-covariance matrices G as well as for correlation matrices R, and an approximate expression of the density function is given. The eigenvalue distribution of all empirical correlation matrices deviates from that of a random pleiotropy model by a very large leading eigenvalue associated with a size factor. However the frequency-distribution of the remaining eigenvalues shows only minor deviations in mammalian skeletal data. A prevalence of intermediate eigenvalues in insect data may be caused by the inclusion of many functionally unrelated characters. Hence two kinds of deviations from random organization have been found: a mammal like and an insect like organization. It is concluded that functionally related characters are on the average more tightly correlated than by chance (= mammal like organization), while functionally unrelated characters appear to be less correlated than by random pleiotropy (insect like organization).     

Obligation and the new naturalism

Although it has become increasingly evident that an adequate theory of obligation must rest on evolutionary biology and human ethology, attempts toward this end need to explore the full range of personal, cultural, and political obligations observed in our species. The new naturalism reveals the complexity of social behavior and the defects of reductionist models that oversimplify the foundations of human duties and rights. Ultimately, this approach suggest a return to the Aristotelian concept of natural justice.