Molecular markers associated with seed weight in two soybean populations

Seed weight (SW) is a component of soybean, Glycine max (L.) Merr., seed yield, as well as an important trait for food-type soybeans. Two soybean populations, 120 F₄-derived lines of YoungxPI416937 (Pop1) and 111 F₂-derived lines of PI97100xCoker 237 (Pop2), were mapped with RFLP makers to identify quantitative trait loci (QTLs) conditioning SW across environments and populations. The genetic map of Pop1 consisted of 155 loci covering 973 cM, whereas Pop2 involved 153 loci and covered 1600 cM of map distance. For Pop1, the phenotypic data were collected from Plains, GA., Windblow, N.C., and Plymouth, N.C., in 1994. For Pop2, data were collected from Athens, GA., in 1994 and 1995, and Blackville, S.C., in 1995. Based on single-factor analysis of variance (ANOVA), seven and nine independent loci were associated with SW in Pop1 and Pop2, respectively. Together the loci explained 73% of the variability in SW in Pop1 and 74% in Pop2. Transgressive segregation occurred among the progeny in both populations. The marker loci associated with SW were highly consistent across environments and years. Two QTLs on linkage group (LG) F and K were located at similar genomic regions in both populations. The high consistency of QTLs across environments indicates that effective marker-assisted selection is feasible for soybean SW.     

Comparison of prevalence of schizophrenia among residents of hostels for homeless people in 1966 and 1992.

OBJECTIVE--To determine whether the prevalence of schizophrenia among the homeless population of Edinburgh resident in hostels has changed between 1966 and 1992. DESIGN--Comparison of two cross sectional surveys. SETTINGS--Hostels for homeless people in Edinburgh. SUBJECTS--In 1966 a random sample of 98 residents of three common lodging houses. In 1992 a random sample of 198 residents of nine hostels. MAIN OUTCOME MEASURE--Prevalence of schizophrenia. RESULTS--The prevalence of schizophrenia in 1992 was 12/136 (9%) compared with 20/79 (25%) in 1966 (odds ratio 0.29; 95% confidence interval 0.13 to 0.62; P = 0.001). Adjustment for confounding by age, current hostel, and duration of unemployment by means of logistic regression produced an adjusted odds ratio of 0.22 (0.08 to 0.58). CONCLUSIONS--The prevalence of schizophrenia was lower in 1992 even after other changes in the population resident in hostels occurring between 1966 and 1992 were taken into account. The findings are not consistent with an increase in the prevalence of schizophrenia among homeless people despite a 66% reduction in adult psychiatric beds in the region during 1966-92.     

Discrimination by male ring-tailed Lemurs (Lemur catta) between the scent marks of male and those of female conspecifics

Olfaction plays an important role in the social communication of all prosimians. (The experiment reported in this paper forms part of an intensive chemobehavioral study of olfaction in Lemur catta (ring-tailed lemur) being carried out in this laboratory.) Five male Lemur cattawere tested on their behavioral responses to paired scent stimuli. Responses measured were (1) total investigation time, (2) arm-marking, (3) ABO/BO rubbing, and (4) flehmen. Males showed a strong discrimination between the scent stimuli,giving higher levels of response to female scent on measures 1, 3, and 4. This response suggests an olfactory-related preference by males for female scent under controlled conditions. This preference may be a consequence of the females’ dominance over males and the brevity of estrus in L. catta,both of which would favor such choice behavior.     

Identification of lipopolysaccharides and phospholipids of Escherichia coli in polyacrylamide gels.

Polyacrylamide gel electrophoresis of unfractionated lysates of radioactively labeled cells resolves not only proteins and polynucleotides into discrete bands but also cellular lipopolysaccharides and phospholipids. This allows a determination of the intracellular amounts of all of these macromolecules. In addition, this technique is sensitive enough to detect mutational alterations in lipopolysaccharide structure. Polyacrylamide gel electrophoresis is herein shown to be a useful tool for investigations into the structure of lipopolysaccharides and the synthesis of lipopolysaccharides and phospholipids.     

Identification and genetics of horse lymphocyte alloantigens

Six hundred horses were tested with lymphocytotoxic antisera derived from 550 parous mares and 58 antisera produced by alloimmunization with horse blood cells. Seven equine lymphocyte specificities were identified using correlation analysis of the test data, absorption analysis and lysostripping. These specificities are expressed on lymphocytes and platelets, but not on red blood cells (RBC). Therefore, these specificities do not appear to be products of any of the eight known blood group systems of the horse. The distribution of these specificities in 113 Thoroughbred horses and 57 Arabian horses is presented. Two specificities are subtypic to two other specificities reported here. Family studies indicated that all of these specificities are products of one genetic system. However, it is not clear whether the system consists of one or more loci.     

Observations on the marginal ruffles of an established fibroblast-like cell line

Summary LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The spines which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone.     

Inhaling and lung cancer: an anomaly explained.

An objective index of inhaling cigarette smoke based on carboxyhaemoglobin concentrations and the carbon monoxide yields of cigarettes was used to investigate possible systematic differences in the extent of inhaling among light and heavy smokers when classified according to their self described inhaling habits. A total of 2108 men who smoked cigarettes were studied. Heavy smokers (20 or more cigarettes a day) had a higher average inhaling index than light smokers (fewer than 20 cigarettes a day) both among those who said that they inhaled and among those who said that they did not. This observation, together with indirect evidence that heavy smokers who inhale deeply may to some extent avoid depositing smoke condensate on their main bronchial epithelium, explains a hitherto unresolved anomaly--namely, that the risk of lung cancer is less among heavy cigarette smokers who say that they inhale than it is among those who say that they do not inhale.     

A circular-dichroism study of epidermolytic toxins A and B from Staphylococcus aureus.

The far-u.v. circular-dichroism spectra of the two epidermolytic toxins was analysed into fractional contributions of 0.09 helix and 0.46 beta-sheet to each toxin structure. Trifluoroethanol perturbation caused an initial increase in dichroic absorption at 205 nm and then a change characterized as a beta-sheet-to-alpha-helix transition. The intense near-u.v. spectra suggested that the toxins have unusually rigid, though different, aromatic-side-chain arrangements.