Laboratoire de Chimie Bactérienne C.N.R.S., Marsielle, France.

Summary Mutants of E. coli, completely devoid of nitrite reductase activity with glucose or formate as donor were studied. Biochemical analysis indicates that they are simultaneously affected in nitrate reductase, nitrite reductase, fumarate reductase and hydrogenase activities as well as in cytochrome c₅₅₂ biosynthesis. The use of an antiserum specific for nitrate reductase shows that the nitrate reductase protein is probably missing. A single mutation is responsible for this phenotype: the gene affected, nir R, is located close to tyr R i.e. at 29 min on the chromosomal map.Abbreviations BV Benzyl-Viologen - NTG N-methyl-N-nitro-N-nitrosoguanidine - NR nitrate reductase - NIR nitrite reductase - FR fumarate reductase - HYD hydrogenase - CYT c₅₅₂ cytochrome c₅₅₂     

Seed structure in Crocus sativus L. ×, C. cartwrightianus Herb., C. thomasii Ten., and C. hadriaticus Herb. at SEM

Crocus sativus L. (Iridaceae) is a sterile triploid geophyte widely cultivated for the production of the spice saffron and only reproduced by means of corms. Extensive research has identified Crocus cartwrightianus Herb. as being a probable progenitor of C. sativus. However, other diploid Crocus species of the same C. sativus group, such as C. thomasii Ten. and C. hadriaticus Herb., have been considered as possible progenitors of saffron. Of the characteristics for distinguishing critical genera, species and intraspecific taxa of angiosperms, the most widely adopted have been seed organisation and patterns of spermoderma microstructure detected at SEM. The aim of this study is to use SEM to analyse the seeds of C. sativus ×, a cross obtained by C. sativus with pollen of C. cartwrightianus Herb. and the seeds of allopollinated C. cartwrightianus, C. thomasii Ten., and C. hadriaticus Herb. Results indicate that the seed surface microstructure of C. sativus × is very similar to that of C. cartwrightianus while being different from those of C. thomasii and C. hadriaticus.     

A Review of: “Biochemistry and Methodology of Lipids,Eds. A.R. Johnson and J.B. Davenport Wiley-Interscience,New York, 1971 x + 578 pages,ill., hard cover; $29.50”

A previous communication from this laboratory¹ as well as one from another³ described the separation of α₂-macroglobulin from swine serum. The products from both laboratories contained, in addition to α₂-macroglob-ulin, an additional macroglobulin contaminant with α₂-globulln mobility. Due to their physicochemical similarity these macroglobulins are not resolved using conventional column procedures such as ion exchange chromatography and gel filtration. Subsequent experiments have shown that immunoelectro-phoretically pure swine α₂-macroglobulln is present, in good yield (65%) in the breakthrough effluent of columns of Bio-Gel A-1.5m-Reactive Blue 2 while the contaminating macroglobulin is tightly bound. The production of highly purified swine α₂-macroglobulin utilizing this observation is the subject of the present report. The product of the separation was found to be homogeneous when subjected to Immunoelectrophoresis, at a concentration of 14–16 mg/ml, and diffused against antiswlne whole serum antibody. The production of monospecific antibody, a more stringent test for homogeneity, resulted when the purified α₂-macroglobulin was injected into rabbits. Physicochemical analyses on the purified product showed that swine and human α₂-macro-globulins are true homologs.