Basic protein and ribonucleic acid in the cytoplasm of the ovarian oocyte in the golden hamster

Summary Cytochemical and autoradiographic studies indicate that granular-fibrillar cytoplasmic bodies and intermitochondrial substance in the hamster ovarian oocyte contain both basic protein and ribonucleic acid. The studies suggest that the granular-fibrillar bodies and intermitochondrial substance, although morphologically similar, are not functionally identical. It is proposed that the granular-fibrillar bodies represent stored inactive maternal messenger RNA synthesized during the lampbrush chromosome stage of oogenesis for use in the developing embryo. The function of the intermitochondrial substance is still obscure. The suggestion is put forward that it may represent the synthetic machinery for the manufacture of those mitochondrial proteins for which the mitochondrial DNA is insufficient to code.The author wishes to thank Mrs. E. M. Lloyd-Davies for her expert technical assistance in preparing the material for autoradiography.     

Ten-year trends in Canada for selected operations

Of 16 operations common in Canada the national rates over a 10-year period for the 9 discretionary procedures varied much more than those for the nondiscretionary operations. The rates of tonsillectomy and adenoidectomy, hemorrhoidectomy, varicose vein stripping and appendectomy decreased substantially, whereas those of extraction of lens, cesarean section and colectomy increased. The rates of hysterectomy and cholecystectomy first increased and then decreased. With the exception of Newfoundland the provinces generally followed these trends. Neither the Canadian nor the provincial rates were significantly associated with the availability of hospital beds or surgeons. Factors other than resources probably accounted for much of the variation among the provinces.     

The evolution of soldier reproduction in social thrips

We estimated the degree of reproductive differentiation betweenfoundresses and soldiers in multiple populations of five speciesof haplodiploid Australian gall-forming thrips using microsatellitedata, ovarian dissections, and census data. Microsatellite-basedspecies estimates of average per capita reproductive outputof soldiers relative to the foundresses ranged from 0.005 to0.64, and dissection and census-based estimates ranged from0.17 to 1.1. Mapping of these estimates onto a phylogeny showedthat levels of soldier reproduction were apparently higherin three basal lineages than in two more derived lineages.We infer from this phylogenetic pattern that soldier morphologyand behavior of thrips evolved in the presence of substantial levels of soldier reproduction. This pattern of evolutionarychange is similar to that proposed for the origin of soldiersin aphids and termites, but it differs from the scenario proposedfor the origin of workers in Hymenoptera, within which helpingand strong reproductive division of labor apparently evolvedbefore morphological differentiation. We suggest that this difference in evolutionary routes to eusociality between taxa with soldiersand taxa with foraging workers was driven by a weaker trade-offbetween helping and reproducing, and a greater ability of thehelpers to withstand reproductive domination, in taxa withsoldiers. This is the first study to analyze the social-evolutionarytrajectories of reproductive, behavioral, and morphologicaldifferentiation in the context of a species-level phylogeny.     

An interdomain linker increases the thermostability and decreases the calcium affinity of the calmodulin N-domain.

A hydrophobic core is a widely accepted determinant of protein stability. However, regulatory proteins undergoing ligand-induced conformational switching may expose interior residues to solvent and cannot afford to be extremely rigid. Optimizing the energetic balance between stability and binding is challenging. The addition of five interdomain residues to rat and Paramecium calmodulin N-domain fragments (residues 1-75) increased their thermostability by 9 degrees C and lowered their calcium affinity by a factor of 4. This demonstrates that the flexible linker regulates functional properties as well as tethering the neighboring domains and that protein stability may be increased markedly by minor modifications of the C-terminus. The sensitivity of this domain to few and conservative variations in helices A and D (D2E, S17A, T70S and M71L) is demonstrated by the rat CaM fragments having lower stability and higher calcium affinity than fragments of the same length derived from Paramecium CaM.     

Identification,RNAi Knockdown,and Functional Analysis of an Ejaculate Protein that Mediates a Postmating,Prezygotic Phenotype in a Cricket

Postmating, prezygotic phenotypes, especially those that underlie reproductive isolation between closely related species, have been a central focus of evolutionary biologists over the past two decades. Such phenotypes are thought to evolve rapidly and be nearly ubiquitous among sexually reproducing eukaryotes where females mate with multiple partners. Because these phenotypes represent interplay between the male ejaculate and female reproductive tract, they are fertile ground for reproductive senescence – as ejaculate composition and female physiology typically change over an individual''s life span. Although these phenotypes and their resulting dynamics are important, we have little understanding of the proteins that mediate these phenotypes, particularly for species groups where postmating, prezygotic traits are the primary mechanism of reproductive isolation. Here, we utilize proteomics, RNAi, mating experiments, and the Allonemobius socius complex of crickets, whose members are primarily isolated from one another by postmating, prezygotic phenotypes (including the ability of a male to induce a female to lay eggs), to demonstrate that one of the most abundant ejaculate proteins (a male accessory gland-biased protein similar to a trypsin-like serine protease) decreases in abundance over a male''s reproductive lifetime and mediates the induction of egg-laying in females. These findings represent one of the first studies to identify a protein that plays a role in mediating both a postmating, prezygotic isolation pathway and reproductive senescence.