Bone mineral density and survival of elements and element portions in the bones of the Crow Creek massacre victims

The interpretation of archaeologically-derived skeletal series is dependent on the elements and portions of elements preserved for examination. Bone and bone portion survival is affected by factors, both intrinsic and extrinsic to the elements themselves, that influence deterioration and preservation. Among the intrinsic variables, the density of the element and element portion are particularly important with respect to the degree of preservation. Recently reported bone mineral density values from a contemporary human sample are compared to the survival of prehistoric limb bones of the Crow Creek specimens, a fourteenth-century massacre skeletal series. The contemporary density values are positively correlated with Crow Creek element and element portion survival. Two calculations of bone mineral density, however, are more closely related to preservation than a third. Such density information has implications for assessing minimum number of elements and individuals and documenting taphonomic processes. Am J Phys Anthropol 104:513–528, 1997. © 1997 Wiley-Liss, Inc.     

Hormonally regulated programmed cell death in barley aleurone cells

Cell death was studied in barley (cv Himalaya) aleurone cells treated with abscisic acid and gibberellin. Aleurone protoplasts incubated in abscisic acid remained viable in culture for at least 3 weeks, but exposure to gibberellin initiated a series of events that resulted in death. Between 4 and 8 days after incubation in gibberellin, >70% of all protoplasts died. Death, which occurred after cells became highly vacuolated, was manifest by an abrupt loss of plasma membrane integrity followed by rapid shrinkage of the cell corpse. Hydrolysis of DNA began before death and occurred as protoplasts ceased production of alpha-amylase. DNA degradation did not result in the accumulation of discrete low molecular weight fragments. DNA degradation and cell death were prevented by LY83583, an inhibitor of gibberellin signaling in barley aleurone. We conclude that cell death in aleurone cells is hormonally regulated and is the final step of a developmental program that promotes successful seedling establishment.     

Genetic recombination of human immunodeficiency virus.

We investigated genetic recombination of the human immunodeficiency virus (HIV) in a tissue culture system. A clonal cell line expressing a single integrated HIV provirus with a termination codon affecting pol gene expression was transfected with different defective mutants derived from an infectious molecular clone of HIV. Replication-competent viral particles were recovered, passaged, and plaque purified. Restriction analyses of the proviral DNA corresponding to several of these viruses indicated that their emergence was the result of genetic recombination.     

Mating behavior ofFlorinda coccinea (Hentz) (Araneae: Linyphiidae)

We studied the courtship and copulation ofFlorinda coccinea (Hentz) and described 18 behavioral acts for this species.F. coccinea exhibits many behaviors typical of the Linyphiidae such as web reduction, abdominal vibration, palpal jabbing, stridulation, pseudocopulation, and prolonged copulation. The numbers of palpal insertions during pseudocopulation and copulation are positively correlated to the durations of these phases. Pseudocopulation requires over three times more time on average than copulation, although females copulate longer than is required for fertilization. We found no correlation between the durations of pseudocopulation or copulation and fitness characters, and we hypothesize that lengthy pseudocopulation and copulation may function as a form of internal courtship.     

Expression of the alpha 1-proteinase inhibitor gene family during evolution of the genus Mus

alpha 1-Proteinase inhibitors (alpha 1-PIs) are members of the serpin superfamily of proteinase inhibitors, and are important in the maintenance of homeostasis in a wide variety of animal taxa. Previous studies have shown that in mice (genus Mus), evolution of alpha 1-PIs is characterized by gene amplification, region-specific concerted evolution, and rapid accumulation of amino acid substitutions. The latter occurs primarily in the reactive center, which is the region of the alpha 1-PI molecule that determines the inhibitor's specificity for target proteinases. The P1 residue within the reactive center, which is methionine in so-called orthodox alpha 1-PIs and an amino acid other than methionine in unorthodox alpha 1-PIs, is a primary determinant of inhibitor specificity. In the present study, we find that the expression of mRNAs encoding unorthodox alpha 1-PIs is polymorphic within Mus species, i.e., among individuals or inbred strains. This is in striking contrast to mRNAs that encode orthodox alpha 1-PIs, whose concentrations are relatively invariant. The intraspecies variations in mRNA expression represent polymorphisms in the structure of the alpha 1- PI gene family. The results, taken together with previously described aspects of alpha 1-PI evolution, indicate that the dissimilar levels of polymorphism exhibited by orthodox and unorthodox alpha 1-PIs, which likely have distinct physiological functions, may reflect different levels of selective constraint. The significance of this finding to the evolution of gene families is discussed.