A rapid methof for preparation of membrane fractions highly enriched in nicotinic acetylcholine receptor from Torpedo californica electroplax is described. The major step in this purification involves sucrose-density-gradient centrifugation in a reorienting rotor. Further purification of these membranes can be achieved by selective extraction of proteins by use of alkaline pH or by treatment with solutions of lithium di-idosalicylate. The alkali-treated membranes retain functional characteristics of the untreated membranes and in addition contain essentially only the four polypeptides (mol.wts. 40000, 50000, 60000 and 65000) characteristic of the receptor purified by affinity chromatography. Dissolution of the purified membranes or of the alkali-treated purified membranes in sodium cholate solution followed by sucrose-density-gradient centrifugation in the same detergent solution yields solubilized receptor preparations comparable with the most highly purified protein obtained by affinity-chromatographic procedures.

Evidence from genetics, co-precipitation and bimolecular fluorescence complementation suggest that three CESAs implicated in making primary wall cellulose in Arabidopsis thaliana form a complex. This study shows the complex has a Mr of approximately 840 kDa in detergent extracts and that it has undergone distinctive changes when extracts are prepared from some cellulose-deficient mutants. The mobility of CESAs 1, 3, and 6 in a Triton-soluble microsomal fraction subject to blue native polyacrylamide gel electrophoresis was consistent with a Mr of about 840 kDa. An antibody specific to any one CESA pulled down all three CESAs consistent with their occupying the same 840 kDa complex. In rsw1, a CESA1 missense mutant, extracts of seedlings grown at the permissive temperature have an apparently normal CESA complex that was missing from extracts of seedlings grown at the restrictive temperature where CESAs precipitated independently. In prc1-19, with no CESA6, CESAs 1 and 3 were part of a 420 kDa complex in extracts of light-grown seedlings that was absent from extracts of dark-grown seedlings where the CESAs precipitated independently. Two CESA3 missense mutants retained apparently normal CESA complexes as did four cellulose-deficient mutants defective in proteins other than CESAs. The 840 kDa complex could contain six CESA subunits and, since loss of plasma membrane rosettes accompanies its loss in rsw1, the complex could form one of the six particles which electron microscopy reveals in rosettes.

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Torpedo californica postsynaptic membrane fragments were treated with base, which resulted in membranes that were depleted of many nonacetylcholine receptor polypeptides and contained acetylcholine receptor subunits of Mr 40,000, 50,000, 60,000, and 65,000 (Raftery, M. A., Vandlen, R.

Escherichia coli pel- mutants inhibit the penetration of bacteriophage lambda DNA into the cell. Using P1 mediated cotransduction, we mapped pel- mutations between markers fadD and eda in the interval of minute 40 of the revised E. coli K-12 map. This places pel in the same region as genes kdgR and ptsM. Mutations in kdgR usually do not alter the Pel phenotype, and vice versa. In contrast, about 30% of ptsM- mutants are also pel-, and all pel- mutants isolated are ptsM-. These results suggest that pel and ptsM are one and the same gene. This interpretation would identify the bacterial product required for injection of phage lambda DNA as a component of the phosphoenolpyruvate-dependent phosphotransferase system specific for mannose, glucosamine, glucose and fructose. However, the experimental results do not exclude an alternative explanation: that pel and ptsM identify two closely linked genes which would be simultaneously affected at high frequency by a particular mutational event.

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The longitudinal data from the Terman Genetic Studies of Genius were used to predict suicide in 40 women: 8 suicides, 15 women who were matched with the suicides on age of death, and 17 subjects who were still living in 1964. Seven variables from the subjects 1 files were assessed as possible predictors of suicide: subject's physical health, early loss of the father, stress in the family of origin, problems with alcohol, and three indices of mental health. A discriminant function analysis was able to differentiate the women who committed suicide from the two control groups. A seven-variable function predicted 100% of the suicides. A four-variable function predicted 75% of the suicides. The results indicate that suicide risk factors can be identified in women and certain "signatures" of suicide are as useful in predicting female suicide as male suicide.The psychological turmoil surrounding people who commit suicide has often been chronicled in psychological autopsies that describe the forces pushing a person toward suicide (Shneidman, 1981;Weisman, 1974). These psychological autopsies are retrospective, beginning with the fact of suicide and looking for harbingers of death in the days, weeks, and months preceding suicide (Niswander, Casey, & Humphrey, 1973). Although such retrospective studies have yielded numerous factors associated with increased suicide (Lester, 1983;Neuringer, 1974), these factors have rarely been validated as predictors of suicide in prospective studies.The Lundby study, conducted in Sweden, is the only prospective study of suicide currently available that used a representative sample. This study, which followed over 3,000 adults for 25 years, included periodic mental health evaluations for a representative sample of the Swedish population (Hagnell, Lanke, & Rorsman, 1981;Hagnell & Rorsman, 1980). So few women from this group committed suicide, however, that the investigators limited their analysis to the 23 male suicides.An alternative strategy that has been used to validate predictors of suicide is to follow psychiatric populations (Borg & Stahl, 1982;Juel-Nielsen, 1979;Robin, Brooke, & Freeman-Brown, 1968) or alcoholics (Berglund, 1984). The subjects in these studies are individuals who have been admitted to a hospital. Once they come to the attention of the mental health profession, these in-