Function of the <Emphasis Type="Italic">rel</Emphasis> Gene in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Sokawa et al. suggest that rel^- strains of Escherichia coli possess abnormal protein synthesizing machinery, which cannot carry out normal protein synthesis when the supply of amino-acids is limited.     

“Pleiotypic Response”

A hypothesis has been developed to relate stringent control in bacteria to a set of interactions involved in the regulation of growth of transformed and untransformed mammalian cells.     

Inhibition of DNA Synthesis but not of Poly-dAT Synthesis by the Arabinose Analogue of Cytidine <Emphasis Type="Italic">in vitro</Emphasis>

Kimball and Wilson¹ reported that the arabinose analogue of cytidine (ara-C) inhibited DNA polymerase in a crude extract prepared from Ehrlich ascites cells. Furth and Cohen² observed cytosine arabinoside triphosphate (ara-CTP) inhibited DNA polymerase in extracts from either calf thymus or bovine lymphosarcoma tissue, although these investigators³ had already found no effect of ara-CTP on DNA polymerase from Escherichia coli. The inhibition in both of these cases could be substantially reversed by dCTP; but incorporation of the arabinose nucleotide (ara-CMP) into DNA could not be unequivocally demonstrated. Graham and Whitmore⁴ reported the incorporation of ara-C into DNA in vivo and the inhibition of a DNA polymerase from L cells by ara-CTP. They found that ara-CMP was initially incorporated into small DNA strands but subsequently appeared in long strands. Momparler⁵ has presented evidence that, in vitro, ara-C incorporation was limited to the 3′-hydroxyl end of DNA chains. Such incorporation might be expected to block further chain elongation but this expectation was not supported by the evidence presented by Graham and Whitmore.     

Endopeptidase Activity of Phage λ-Endolysin

JACOB and Fuerst^1,2 demonstrated the presence of a bacteriolytic enzyme (λ-endolysin) in the induced cultures of lysogenic Escherichia coli K12 (λ). The enzyme was later identified as the product of gene R; of phage λ³ which is involved in bacterial lysis at the end of a latent period. The enzyme is apt to form spheroplast-like structures in E. coli² and one would therefore expect its substrate to be murein.     

PALEOZOIC LYCOPSID FRUCTIFICATIONS. I. LEPIDOCARPON PETRIFACTIONS

A reinvestigation of the 4 American species of Lepidocarpon described from petrifactions and of Illiniocarpon cadyi, also described from petrifactions, shows that they are all conspecific. When they, in turn, are compared with specimens of the British petrifaction L. lomaxi, no significant differences can be demonstrated. The criteria cited as diagnostic for the American petrifaction species of Lepidocarpon were found to fail as bases of discrimination when 400 specimens of Lepidocarpon found in coal balls of Pennsylvanian age were studied. Measurements and observations made of a sample size of 136 of these 400 specimens reveal a degree of variation compatible with that of a single species. All previously described American and British petrifaction taxa fall within (or not significantly beyond) this range of variability of a single species as determined from this sample. Additional evidence concerning the 3-dimensional sporophyll structure of this one species of Lepidocarpon and the configurations obtained by certain planes of section through it have served to demonstrate that Illiniocarpon cadyi is in reality a taxon based on sectioned structures of the sporophyll of this Lepidocarpon species. Under the rules of priority, this species of Lepidocarpon and the following are assigned to Lepidocarpon lomaxi: Illiniocarpon cadyi, Lepidocarpon ioense, L. magnificum (megasporangiate form), L. crenatum and L. palmerensis. On the basis of the morphological evidence, the British petrifaction described as Lepidocarpon wildianum is also equated with L. lomaxi.     

HYBRIDS AND GENOME RELATIONS OF HIBISCUS SABDARIFFA,H. MEEUSEI,H. RADIATUS AND H. ACETOSELLA

Chromosome pairing was studied in the following hybrids: Hibiscus radiatus-meeusei (tetraploid F₁), H. sabdariffa-meeusei (tetraploid F₁ and spontaneous allooctoploid F₂), and hexaploid H. acetosella-(sabdariffa-meeusei). Genome constitutions of the species adduced from these data are symbolized as follows: H. radiatus and H. acetosella, AABB; H. meeusei, AAXX; H.sabdariffa, XXYY or AAYY.     

On being ethnic: The politics of identity breaking and making in Canada,or, Nevra on Sunday

The creation of ethnically sensitive health care is a major federal and provincial government concern in Canada at present. The concept of multiculturalism is used to reinforce the notion of rights for minority groups and the Canadian mozaic is explicitly contrasted with the American melting pot. In this paper, the lives of Greek immigrant women in Montreal are used to illustrate how class and gender are as relevant to the immigrant experience as is ethnicity. It is shown how values which were central to female identity in Greece can become a liability after immigration and how the notion of Greek identity in Canada is a fluid category which is subject to repeated transformations. It is suggested that medical anthropologists who ignore the complexity of social categories and whose focus is limited to the cultural construction of illness and the expression of distress are in danger of reinforcing a notion of the quaint ethnic, a stereotype to which the concept of multiculturalism is often reduced.

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Résumé La création de services de santé sensibles aux besoins des différents groupes ethniques est présentement un socci majeur des gouvernements fédéral et provincial au Canada. Le concept de multiculturalisme est utilisé pour renforcer I'idée des droits des groupes minoritaires et la mosaïque canadienne est explicitement contrastée avec the American melting pot. Dans cet exposé, j'utilise la vie des femmes immigrantes grecques à Montréal pour démontrer que la classe et le sexe sont aussi pertinent par rapport à l'expérience des immigrants que l'ethnicité. On montre de quelle façon les valeurs qui sont centrales à l'identité féminine en Grèce peuvent en venir à constituer un problème après l'immigration et comment la notion d'identité grecque au Canada est une catégorie fluide qui est sujette à de multiples transformations. On suggère que les anthropologues médicaux qui ne tiennent pas compte de la complexité des catégories sociales et dont le centre d'intérêt est limité à la cultural construction of illness et à l'expression of distress courent le danger de renforcer la notion de quaint ethnic, un stéréotype auquel le concept de multiculturalisme se trouve souvent réduit. Notes 1 See, for example, Low 1985; Davis 1989; Dunk 1989; Guarnaccia et al. 1989; Van Schaik 1989. 2 Data for this study were obtained initially from eighty-three fast generation Greek immigrant women living in Montreal who were given semi-structured interviews in Greek in their homes. It became apparent in the course of carrying out these interviews that the concept of nevra was central in the narratives given by virtually all of the respondents. This term was inevitably used to link environmental and psychosocial variables to distress and painful physical states. In the second phase of the research, 19 of the original women were selected for in-depth open-ended interviews during which the concept of nevra was discussed in detail. A further data set was obtained from twenty five women who were interviewed in the office of a Greek Canadian general practitioner and 15 more attending a poly-clinic in a Montreal teaching hospital. These interviews were carried out in order to establish if nevra is used as a presenting complaint in clinical settings, and if so, how it is managed by health care professionals. Several internists, psychiatrists, family and general practitioners, and social workers who have daily contact with Greek patients were also interviewed.