Reproductive cycles ofSebastes taczanowskii,compared with those of other rockfishes of the genusSebastes

Synopsis Seasonal reproductive cycles were examined in both sexes ofSebastes taczanowskii, captured in southern Hokkaido, Japan. The reproductive cycle in females was divided into four periods: recovery (July–August), vitellogenesis (September–March), gestation (April–May) and parturition (June). Spermatozoa were first observed in November in the ovarian cavity, where no structural specialization was present for sperm storage. Fertilization of oocytes appeared to occur in April, when the oocytes underwent a rapid process of final maturation. Embryos developed in the ovary quite synchronously and were released in June; empty ovaries indicated the rockfish has a single parturition. The reproductive cycle in males comprised five periods: resting (December–July), early maturation (February–May), mid-maturation (June–August), late maturation (September–October) and functional maturation (November). In November when active spermatogenesis had been completed, a large amount of spermatozoa was preserved in the sperm duct, and the males were therefore ready for mating. A comparison was made of the reproductive cycles of four species of the genusSebastes inhabiting southern and northern waters of Japan. It suggests that the northern species tend to prolong gametogenesis in both sexes while the southern species have the opposite tendency. Sperm storage in the ovary also tends to be longer in the northern than in the southern species.     

Stimulation of growth by testosterone via the mesenchyme

Summary To establish testosterone-dependent growth in organ-culture, anlagen of preputial glands from normal wild-type and from androgeninsensitive mouse embryos carrying the testicular feminization mutation (Tfm) were explanted and cultured in the presence of testosterone. Within six days a size difference developed between Tfm and wild-type explants involving length of hair follicle, amount of preputial gland tissue, and overall size.Anlagen from Tfm and wild-type preputial glands were then separated into epithelial bud and mesenchyme. Reciprocal recombinants were prepared and cultured with testosterone. In the recombinants development of hair follicles and gland tissue was inconsistent. Nevertheless, the effect of testosterone was expressed in the overall size of the explants. The size correlated with the type of mesenchyme used, but not with the type of epithelium: Androgen-insensitive Tfm epithelium combined with wild-type mesenchyme reached the same size as whole wild-type glands and wild-type/wild-type recombinants. Wild-type epithelium with Tfm mesenchyme resulted in small explants, which were in the range of the whole androgen-insensitive Tfm glands. Tfm/Tfm recombinants showed very poor growth, probably related to the fact that in this group no hair or gland structures developed.     

Influence of the glycosidic torsion angle on 13C and 15N shifts in guanosine nucleotides: Investigations of G-tetrad models with alternating syn and anti bases

Summary The effect of the glycosidic torsion angle on ¹³C and ¹⁵N shifts of the sugar and base moieties of guanosine nucleotides was investigated by comparing the sites in two model G-tetrad oligodeoxynucleotides that contain guanosine residues alternately with syn and anti bases. The sugar puckering has been shown to be C2-endo for both cases. It was observed that, for the instances with syn bases, the C1 through C4 carbons showed shifts that may be distinguished from those normally found in B-DNA-like structures. C1, C3 and C4 moved to lower field, while C2 moved to higher field. Effects of the change in glycosidic torsion angle were also seen in the shifts of base carbons and nitrogens in the five-membered ring portion of the base. Characterization of the shift variation associated with this conformational change may be useful in developing the use of ¹³C shifts as a tool in conformational analysis of oligonucleotides.Part of the work reported here derives from the Ph.D. Thesis of Karen L. Greene, Emory University, Atlanta, GA, 1991.     

Basal lamina of human seminiferous tubule—Its role in material transport

Summary Electron microscopy of testicular biopsies obtained from two adult males with tunica vaginal hydrocele revealed some protrusions from the basal lamina to the germinal epithelium in the seminiferous tubule. The protrusions were of three types: some between the spermatogonia and Sertoli cells, some directly within the Sertoli cell cytoplasm and others inside the spermatogonia. The protrusions inside the spermatogonia were only 0.5 m deep whereas the other types were from 1–11 m deep. Occasionally some cut off portions of these protrusions were seen inside the ground cytoplasm of the Sertoli cell without an apparent connection with the original stalk. The matrix of the protrusions contained a homogenous component (composed of a fine filamentous element) and granular and membranous components. These components closely resemble the materials found in the basal lamina of the seminiferous tubule. It has been suggested that under mild pathological conditions, i.e., hydrocele, the junctions between the seminiferous tubule epithelium and the basal lamina become somewhat more flexible. As a result, the protrusions become longer and a passage might be formed to allow the flow of raw materials in or out of the seminiferous tubule.This work was supported by USPHS Research Grant HD-03266 and GRS 94802     

Spermatogenesis‐associated proteins at different developmental stages of buffalo testicular seminiferous tubules identified by comparative proteomic analysis

The testicular seminiferous tubules contain Sertoli cells and different types of spermatogenic cells. They provide the microenvironment for spermatogenesis, but the precise molecular mechanism of spermatogenesis is still not well known. Here, we have employed tandem mass tag coupled to LC‐MS/MS with the high‐throughput quantitative proteomics technology to explore the protein expression from buffalo testicular seminiferous tubules at three different developmental stages (prepuberty, puberty, and postpuberty). The results show 304 differentially expressed proteins with a ≥2‐fold change, and bioinformatics analysis indicates that 27 of these may be associated with spermatogenesis. Expression patterns of seven selected proteins were verified via Western blot and quantitative RT‐PCR analysis, and further cellular localizations of these proteins by immunohistochemical or immunofluorescence analysis. Taken together, the results provide potential molecular markers of spermatogenesis and provide a rich resource for further studies on male reproduction regulation.     

Effects of ethylene glycol on the torsion elastic constant and hydrodynamic radius of p30delta DNA

Upon increasing the concentration of ethylene glycol (EG) at 37 degrees C, the twist energy parameter, E(T), which governs the supercoiling free energy, was recently found to undergo a decreasing (or reverse) sigmoidal transition with a midpoint near 20 w/v % EG. In this study, the effects of adding 20 w/v % EG on the torsion elastic constant (alpha) of linear p30delta DNA and on the hydrodynamic radius (R(H)) of a synthetic 24 bp duplex DNA were examined at both 40 and 20 degrees C. The time-resolved fluorescence intensity and fluorescence polarization anisotropy (FPA) of intercalated ethidium were measured in order to assess the effects of 20 w/v % EG on: (1) alpha; (2) R(H); (3) the lifetimes of intercalated and non-intercalated dye; (4) the amplitude of dye wobble in its binding site; and (5) the binding constant for intercalation. The effects of 20 w/v % EG on the circular dichroism (CD) spectrum of the DNA and on the emission spectrum of the free dye were also measured. At 40 degrees C, addition of 20 w/v % EG caused a substantial (1.27- to 1.35-fold) increase in alpha, a significant change in the CD spectrum, and a very small, marginally significant increase in R(H), but little or no change in the amplitude of dye wobble in its binding site or the lifetime of intercalated dye. Together with previously reported measurements of E(T), these results imply that the bending elastic constant of DNA is significantly decreased by 20 w/v % EG at 40 degrees C. At 20 degrees C, addition of 20 w/v % EG caused a marginally significant decrease in alpha and very little change in any other measured properties. Also at 20 degrees C, addition of 30 w/v % betaine caused a marginally significant increase in alpha and significant but modest change in the CD spectrum, but very little change in any other properties.     

Computational basis of knowledge-based conformational probabilities derived from local- and long-range interactions in proteins

The probabilities of the various basins in Ramachandran maps are examined critically. The theoretical basis of probability calculations both from molecular computations and from protein libraries are discussed. The well-defined basins of the Ramachandran maps are treated as rotational isomeric states. Statistical independence and dependence of the states of different residues along the peptide chain are discussed. The Flory isolated pair hypothesis, near neighbor correlations, context effects, and long-range correlations are examined critically. A method of evaluating long-range correlations in helical and extended sequences is introduced in analogy with earlier polymer theory. Three different protein libraries are constructed where data is considered from residues in the (i) coiled regions, (ii) all regions, and (iii) only the helical and extended regions of proteins. Singlet and pairwise dependent probabilities calculated from these libraries are used to predict whether a given sequence is helical or extended. Predictions using pairwise dependence were not better than those using singlet probabilities. Modeling of long-range correlations improved the predictions significantly. Removal of the Chameleon sequences from the data set also improved the predictions, but to a lesser extent.     

Two cases of liver lobe torsion in a white‐lipped tamarin (Saguinus labiatus) and an Alaotran gentle lemur (Hapalemur alaotrensis)

This paper describes liver lobe torsion in a white‐lipped tamarin (Saguinus labiatus) and an Alaotran gentle lemur (Hapalemur alaotrensis). Both animals had a history of acute collapse, and diagnosis was made post‐mortem. To the authors’ knowledge, these are the first reported cases of this pathology in non‐human primates.