Robert M. Syren

Membrane, action, and oscillatory potentials in simulated protocells

Electrical membrane potentials, oscillations, and action potentials are observed in proteinoid microspheres impaled with (3 M KCl) microelectrodes. Although effects are of greater magnitude when the vesicles contain glycerol and natural or synthetic lecithin, the results in the purely synthetic thermal protein structures are substantial, attaining 20 mV amplitude in some cases. The results add the property of electrical potential to the other known properties of proteinoid microspheres, in their role as models for protocells.

Geographic variation of sex-linked translocation heterozygosity in the termite Kalotermes approximatus snyder (Insecta: Isoptera)

The primitive termite Kalotermes approximatus carries a number of reciprocal translocations (segmental interchanges) that are linked to the sex-determining mechanism in such a way that males are permanent structural heterozygotes, forming long chains or rings of chromosomes in meiosis, while females are structural homozygotes, forming only bivalents. A survey of male meiosis from collections covering nearly the whole species range in the southeastern United States reveals considerable variation in the number of translocations: males with a diploid number of 32 or 33 have meiotic chains of 11, 13, 14, 15, 16, and 17 or 19 chromosomes. The different types can be arranged in an evolutionary series of rearrangements involving translocations or Robertsonian fusions between chromosomal elements in the ring and those outside. In addition, the existence of a closed chain (ring) of 16, and of four different types of chain of 13, indicate that similar rearrangements have occurred among chain elements. The geographic pattern of these rearrangements suggests that their selection accompanied the expansion of the species northward from southern Florida sometime since the last glaciation or, alternatively, that as they arose the new translocation types successively supplanted the ancestral types, preferentially in the east-central portion of the range.

Ancient microspheres: Abiogenic, protobiogenic, or biogenic?

Criteria of biogenicity of microspheroidal objects, which have been interpreted as microfossils, are here reviewed in the light of additional data. Much weight has been placed by some commentators on constrained heterogeneity as a primary criterion of biogenicity. The data from the field and laboratory suggest the need for continuing reservation in the interpretation of these objects. On the basis of these and other data, reasons are given for the alternative explanation that the objects are lithified relics of protobiotic assemblages. The question remains open as to whether the early Archean spheroidal objects are abiotic, protobiotic, or biotic in origin.

Effect of products from heated amino acids on conductance in lipid bilayer membranes and non-aqueous solvents

The electrical conductance of lipid bilayer membranes of oxidized cholesterol is elevated 102–103 times by the addition of various products of the heating of amino acids. Solution of such products in chloroform yields a greater increase in conductance. The results are obtained with both water-soluble and water-insoluble fractions. They are discussed in the context of the origin of electroconductive tissue.

Experimental hybridization between chromosomal races in Kalotermes approximatus, a termite with extensive sex-linked translocation heterozygosity

In order to elucidate the evolutionary pathway of sex-chromosome translocations in the termite Kalotermes approximatus, reciprocal matings were made between the winged reproductives from two different colonies, one in which there was a multivalent chain of 13 in male meiosis, and one in which there was a chain of 17 (or 19, in some cells). From the cross in which the male parent came from the chain-of-13 colony, the male offspring had a chain of 13 (or 15, in some cells) in meiosis; from the reciprocal cross, the male offspring had a chain of 15. Careful analysis of the multivalent chains in the hybrid males, combined with previous observations on chromosome variation in this species (Syren and Luykx, 1981), permit the following conclusions: (i) The two parent colonies differ by five distinct translocations, involving both X and Y chromosomes. (ii) In the evolution of the sex-multivalent, all of these kinds of translocations have occurred: X-X, Y-Y, X-autosome, and Y-autosome. (iii) Out of a total of 8 sex-chromosome translocations that can now be unambiguously characterized, 6 have involved X-chromosomes, and 2 have involved Y-chromosomes. (iv) In this species, different chromosomal races in adjacent geographic locales may differ in both their males and their females (where translocations have involved X-chromosomes), or they may differ only in their males (where translocations have involved Y-chromosomes).

A Test-Scoring/Item Analysis SAS Program for the IBM Mainframe

This paper presents an item analysis program written in SAS that can be implemented in a central computing facility to provide test scoring support in an academic environment.