Reduction and azo coupling of quinones

Summary Cutaneous melanin in formol fixed skin and adrenochrome in dichromate fixed monkey adrenal after adequate bisulfite or dithonite reduction were found to give definite azo coupling reactions. Weaker reactions were obtained on unreduced material, and these disappeared on ferric chloride oxidation. Both cutaneous melanin and adrenochrome appear to exist in a quinhydrone status. Prolongation of dichromate treatment weakens or abolishes azo coupling capacity of adrenochrome. The findings support the concept of quinonization and reduction to prevent and restore azo coupling of enterochromaffin cells and noradrenaline islets of the adrenal.The most effective diazos for melanin werep-nitrodiazobenzene, fast black K and the diazosulfanilic acid, pH 1 pyronin B procedure, for adrenochrome. Diazosafranin and 2-chloro-4-nitrodiazobenzene were also useful. Blue and violet coupling products from toluidine blue and methylene violet RR fail to yield sufficient contrast to be convincing.     

CORRECTION OF THE NAME PSEUDOTETRAÉDRON POLYMORPHUM (CHLOROPHYCEAE)1

A unicellular chlorococcalean alga, Pseudotetraëdron polymorphum MacEntee, Bold & Archibald is renamed Chlorotetratëdron polymorphum (MacEntee, Bold & Archibald) MacEntee, Bold & Archibald became the former generic designation has been preempted by a xanthophycean alga.     

AMMONIUN AND NITRATE UPTAKE BY THE MARINE MACROPHYTES HYPNEA MUSVUFORMIS (RHODOPHYTA) AND MACROCYSTIS PYRIFERA (PHAEOPHYTA)1, 2

NH₄⁺ and NO₃^? uptake were measured by continuous sampling with an autoanalyzer. For Hypnea musciformis (Wulfen) Lamouroux, NO₃^?up take followed saturable kinetics (K₂=4.9 μg-at N t^?1, V_max= 2.85 μg- at N, g(wet)^?1. h^?1. The ammonium uptake data fit a trucatd hyperbola, i.e., saturation was not reach at the concentrations used. NO₃^? uptake was reduced one-half in the presence of NH₄⁺, but presence of NO₃^? had no effect on NH₄⁺ uptake. Darkness reduced both NO₃^? and NH₄⁺ uptake by one-third to one-half. For Macrocystis pyrufera (L) C. Agardh, NO₃^? uptake followed saturable kinetices: K₂=13.1 μg-at N. l^?1. V_max=3.05 μg-at N. g(wet)^?1. h^?1.NH₄⁺ uptake showed saturable kinetics at concentration below 22 μg-at N l -1 (K₂=5.3 μg-at N.1–1, V_max= 2.38 μg-at N G (wet)^?1.h^?1: at higher concentration uptake increased lincarly with concentrations. NO₃^?and NH₄⁺ were taken up simulataneously: presence of one form did not affect uptake of the other.     

Relationship of F9 antigen and genes of theT/t complex

Serological studies relating F9 antigen of embryonal carcinoma cells to at the murineT/t complex have been extended and confirm that only the lethal haplotype t¹²- and none of the other five lethal haplotypes-affects the quantitative expression of F9 antigen on sperm. Cytotoxicity tests on preimplantation embryos show that t¹² homozygotes are less susceptible to antiF9 serum than t^w5 homozygotes, and that using specific antimutant haplotype antisera prepared against sperm, t¹² antigen is detectable on morulae, whereas t^w5 antigen is not.     

Two early mississippian seeds from the price formation of Southwestern Virginia

Lagenospermum imparirameum Arnold, originally described from a few specimens of cupulate seeds borne on two or three times dichotomous branches, is now shown to be borne on more complex branching systems. Details of the cupule and seed morphology are added and an emended diagnosis of the taxon is given. A new species,Gnetopsis hispida, is described as the third occurrence of this genus and the first occurrence in beds of Lower Mississippian Age in North America. The classification, evolutionary implications, and dispersal biology are discussed for each of the seeds     

Morphologic and taxonomic relationships of the Psilotaceae relative to evolutionary lines in early land vascular plants

Examination of the fossil record shows that there is no direct evidence regarding the origins and early evolution of the Psilotaceae. Past comparisons betweenPsilotum orTmesipteris and certain fossil plants are reviewed. The major types of early land vascular plants are surveyed in order to demonstrate their basic characteristics and evolutionary trends and to point out the absence of any direct links with the Psilotaceae. Fossil plants of problematical affinities which appear to be important in the early diversification of ferns or plants closely related to ferns are discussed. The nature of stem-leaf relationships of some primitive, extant filicalean ferns and possibly the Psilotaceae is considered in terms of possible similar occurrences among fossil plants.     

Isopycnography of intact cells — V: The kinetics of the initiation of DNA synthesis in E. coli undergoing nutrient shift-up

Manipulation of the ribosome content of E. coli by means of a nutrient shift-up leads to predictable changes in cellular specific gravity. Thus whole-cell pycnography can be used to monitor the proliferative status of the rRNA loci which cluster closely about the genetic origin of DNA synthesis. In this manner the rate of initiating new rounds of genome replication was followed during an upshift. The results indicate that after a short lag initiation of new rounds abruptly and completely shifts to the rate appropriate to the enriched conditions.