Viability and acrosome integrity of rabbit spermatozoa processed in a gelatin-supplemented extender

The effect of gelatin addition to the semen extender on the viability and acrosome integrity of rabbit spermatozoa was studied. Pooled semen samples were processed in a boar semen extender with or without gelatin addition. Semen samples were stored at 5 °C for 72 h. Viability and acrosome integrity was evaluated by light microscope. Results showed that gelatin addition had a significant positive effect on the quality of the stored semen.     

Rolling properties of rGPIbalpha-conjugated phospholipid vesicles with different membrane flexibilities on vWf surface under flow conditions

The recombinant fragment of the platelet membrane glycoprotein, rGPIbalpha, was conjugated to phospholipid vesicles with the average diameter of ca. 1 microm using N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). We used five kinds of rGPIbalpha-vesicles with different fluorescent anisotropies of 1,6-diphenyl-1,3,5-hexatriene (DPH) to study the rolling properties of the vesicles on the von Willebrand factor (vWf)-immobilized surface. Under flow conditions, the rolling velocity of the rGPIbalpha-vesicles decreased with the increasing membrane flexibility. It is considered that the vesicles with a high membrane flexibility have a high deformability and can be flattened to a high degree during rolling on the vWf surface, thus resulting in the large contact area. We obtained a recipe to control the rolling velocity of artificial platelets by membrane flexibility.     

Age-related changes of element contents in human tendon of the iliopsoas muscle and the relationships among elements

To elucidate compositional changes of the tendons with aging, the authors investigated age-related changes of element contents in the tendon of the iliopsoas muscle by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 14 men and 14 women, ranging in age from 4 to 102 yr. The insertion tendons of the iliopsoas were removed from the cadavers after ordinary dissection and also surgically from patients with congenital dislocation of the hip. It was found that both Mg and P in the tendon of the iliopsoas muscle increased significantly with aging, but the other elements, such as S, Ca, Na, Zn, Fe, and Si, hardly changed with aging. With regard to the relationship among element contents, extremely significant correlations were found between P and S contents, between Mg and Na contents, and between S and Zn contents. In addition, very significant correlations were found between Si and either S or Zn contents. However, there was no significant correlation between Ca and P contents. These results revealed that with regard to age-related changes of element contents and the relationships among element contents, the tendon of the iliopsoas muscle was different from the Achilles tendon, in which both Mg and P decreased significantly with aging and there were significant correlations each other among the contents of S, Mg, and P.     

Mapping candidate hotspots of meiotic recombination in segments of human DNA cloned in the yeast<Emphasis Type="Italic"> Saccharomyces cerevisiae</Emphasis>

The hotspots of meiotic recombination in the human genome can be localized by genetic techniques. The resolution of these techniques is in the range of kilobases and depends on the density of the physical markers identifying allelic variants of the chromosomal loci. We thought it would be interesting to localize these sites with higher resolution. Assuming that some human chromosomal sites conserve their propensity for recombination when cloned in yeast, we localized the hotspots of recombination in several yeast artificial chromosomes (YACs) carrying human DNA. A number of potential recombination hotspots could be identified in the clones studied. Among them there are two classes of sites that are particularly recombination prone also in human meiotic cells: sites associated with CpG islands and sites located in the vicinity of long minisatellite sequences.Communicated by G. P. Georgiev     

Measuring tolerance to herbivory: accuracy and precision of estimates made using natural versus imposed damage

Abstract.— Tolerance to herbivory (the ability of a plant to incur herbivore damage without a corresponding reduction in fitness) can be measured using either naturally occurring or imposed herbivore damage. After briefly reviewing some of the advantages and disadvantages of these approaches, we present calculations describing the degree to which estimates of tolerance will be biased by environmental variables that affect both herbivory and fitness. With naturally occurring herbivory the presence of environmental variables that are correlated with herbivory and fitness will result in biased estimates of tolerance. In contrast, estimates obtained from experiments in which herbivory is artificially imposed will be unbiased; however, under a wide range of parameter values these estimates will be less precise than estimates obtained from experiments in which herbivory is not manipulated.     

Age-dependent decreases of phosphorus and magnesium in human achilles’ tendons

To elucidate changes of human tendons with aging, the authors studied age-related changes of elements in human Achilles’ tendons by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. It was found that the content of calcium increased progressively with aging in the Achilles’ tendons, whereas the contents of phosphorus and magnesium decreased gradually with aging. The previous investigations demonstrated that the content of calcium and phosphorus increased progressively with aging in most, but not all, human tissues, except for the bones. In ligaments, such as the anterior cruciate ligament and the ligament of the head of the femur, which are histologically similar to the Achilles’ tendon, it was previously found that both the contents of calcium and phosphorus increased with aging in the ligaments. It should be noted that the content of phosphorus in the Achilles’ tendons decreased during the aging process. In addition, it was found that there was a very high direct correlation between phosphorus and magnesium contents in the tendons, but not between calcium and phosphorus contents.     

Successful artificial insemination for indoor breeding in the Japanese monkey (Macaca fuscata) and the cynomolgus monkey (Macaca fascicularis)

Methods of artificial insemination (AI) for indoor breeding in the Japanese monkey and the Cynomolgus monkey were investigated. For the Japanese monkey AI was carried out in six females during the winter mating season and in six females during the summer non-mating season. During the mating season, semen was inseminated near ovulation time in natural menstrual cycles. In the mating season study, three females inseminated at the uterine cavity became pregnant. Three inseminated at the cervical canal failed to become pregnant. For the non-mating season study, ovulation was induced artificially by PMSG and hCG and AI was carried out near the induced ovulation time. In the non-mating season, no animals became pregnant. Of four Cynomolgus monkeys used, pregnancy occurred in two animals inseminated near ovulation time in natural menstrual cycles. AI occurred at the uterine cavity in one and cervical canal in the other. In both species ovulation was verified by laparoscopy. Semen was collected by penile electro-stimulation then diluted to 2.5 to 5.0×10⁷/ml with Whitten's medium. Diluted semen of 0.2l was inseminated at the uterine cavity or cervical canal. Our results indicate the usefulness of vaginal AI as a method of artificial indoor breeding.