Isolation of particulate nitrogenase from Chromatium strain D

A stable particulate nitrogenase was isolated from Chromatiumstrain D by differential sedimentation and density-gradientcentrifugation. Detergent treatment changed the apparent orderof the reaction with respect to enzyme from first to secondorder, but the dissociated components rapidly denatured. Theparticle is believed to represent the in vivo site of nitrogenfixation in Chromatium. ¹Authorized for publication as paper no. 3944 in the journalseries of The Pennsylvania Agricultural Experiment Station onMarch 26, 1971. (Received November 15, 1972; )     

Models for lineal effects in rhesus group fissions

Gene distributions in daughter groups produced by three rhesus monkey group fissions are analyzed. Data employed are for the Tf, 6PGD, and CA II electrophoretic marker systems in the fissions producing new daughter groups F and M, F and O, and J and N in the Cayo Santiago rhesus colony. Wide variations in FST values were observed among the different markers in the various fissions. Overall, the observed FST values exceeded predictions of simple random fissioning models. However, on average, observations on electrophoretic markers fitted well with predicted values from lineal fissioning models. One of these lineal fissioning models, a simulation, incorporated the propagation of alleles in the matrilines of the fissioning groups. The second, an algebraic expression, utilized group sizes and average kinship values as parameters.     

Genetic aspects of migration in a rhesus monkey population

Gene frequency distributions in subdivided populations are affected by migration of individuals between groups. This paper considers the effects of such migration on blood protein allele frequency distributions in social groups of the Cayo Santiago rhesus macaque colony. Gene frequencies for complete social groups and their migrant and natal segments were analyzed at four points within a four year period in the colony's history. Gene frequencies varied between the migrant segments of different groups. Gene frequencies of migrant segments of particular groups also varied substantially with time. Usually, but not always, the presence of migrants in groups reduced the levels of inter-group gene frequency differentiation. We suggest that our findings are explained by a model in which the recruitment of immigrants into social groups is largely random with respect to individual genotypes. Such a model implies that migration contributes to both stochastic and directed changes in gene frequencies in rhesus and similarly substructured populations.     

Methanoplanus limicola,a plate-shaped methanogen representing a novel family,the methanoplanaceae

An angular plate-shaped weakly motile mesophilic methanogen was isolated from a swamp of drilling waste in Italy. Growth occurs on H₂/CO₂ or on formate. Acetate is required in addition. The optimal doubling time is 7 h at 40° C. The cell envelope is composed most likely of glycoprotein subunits in hexagonal arrangement. The GC-content of its DNA is 47.5 mol%. On the basis of DNA-RNA hybridization it was found to represent a new family, the Methanoplanaceae within the order Methanomicrobiales.Abbreviations G+C Guanine+Cytosine - SDS Sodium dodecylsulfate (Sodium lauryl sulfate)     

Phylogeny of carabid beetles as inferred from 18S ribosomal DNA (Coleoptera: Carabidae)

The phylogeny of carabid tribes is examined with sequences of 18S ribosomal DNA from eighty-four carabids representing forty-seven tribes, and fifteen outgroup taxa. Parsimony, distance and maximum likelihood methods are used to infer the phylogeny. Although many clades established with morphological evidence are present in all analyses, many of the basal relationships in carabids vary from analysis to analysis. These deeper relationships are also sensitive to variation in the sequence alignment under different alignment conditions. There is moderate evidence against the monophyly of Migadopini + Amarotypini, Scaritini + Clivinini, Bembidiini and Brachinini. Psydrini are not monophyletic, and consist of three distinct lineages (Psydrus, Laccocenus and a group of austral psydrines, from the Southern Hemisphere consisting of all the subtribes excluding Psydrina). The austral psydrines are related to Harpalinae plus Brachinini. The placements of many lineages, including Gehringia, Apotomus, Omophron, Psydrus and Cymbionotum, are unclear from these data. One unexpected placement, suggested with moderate support, is Loricera as the sister group to Amarotypus. Trechitae plus Patrobini form a monophyletic group. Brachinini probably form the sister group to Harpalinae, with the latter containing Pseudomorpha, Morion and Cnemalobus. The most surprising, well supported result is the placement of four lineages (Cicindelinae, Rhysodinae, Paussinae and Scaritini) as near relatives of Harpalinae + Brachinini. Because these four lineages all have divergent 18S rDNA, and thus have long basal branches, parametric bootstrapping was conducted to determine if their association and placement could be the result of long branch attraction. Simulations on model trees indicate that, although their observed association might be due to long branch attraction, there was no evidence that their placement near Harpalinae could be so explained. These simulations also suggest that 18S rDNA might not be sufficient to infer basal carabid relationships.     

Effects of diazepam on photosynthesis, respiration, rubidium uptake, and finestructure of Scenedesmus obliquus in synchronous cultures.

Effects of diazepam (Valium) on photosynthesis, chlorophyll/photosynthesis ratios, respiration, uptake of rubidium ions, and ultrastructure of Scenedesmus obliquus synchronized by a light-dark regimen of 14:10 hrs were determined. 80 and 160 muM diazepam, added to the nutrient medium at the start of the light-dark change (i.e., start of the cell cycle) gradually reduced rates of photosynthesis, below the initial rates from the beginning of the experiment. Contents of chlorophyll, however, remained nearly unaffected. Consequently, the diazepam-treated cells had a higher chlorophyll/photosynthesis ratio--also with regard to respiration in order to calculate the gross photosynthesis. The occurrence of photorespiration cannot be assumed. The net influx of rubidium was slightly reduced by 100 muM diazepam 0.5 and 2.0 hrs after the start of the cell cycle and was strongly inhibited after 5 to 14 hrs. 80 and 160 muM diazepam caused separation of thylakoids, formation of giant mitochondria and enlargement of vacuoles.