Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms

We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.

Identification and sequencing the juvenile spermatogonial depletion critical interval on mouse chromosome 1 reveals the presence of eight candidate genes

In mice, the recessive, non-pleiotropic, juvenile spermatogonial depletion (jsd) mutation results in a single wave of spermatogenesis, followed by failure of type A spermatogonial stem cells to differentiate, rendering adult males sterile. As part of an effort to identify the gene underlying this mutation, we report here the construction of a high-resolution genetic map involving more than 1000 meioses and 24 polymorphic loci. Our data define a critical jsd interval of approximately 0.4 cM at 49 cM on mouse chromosome 1, between D1Mit215 and 257SP6. We have constructed a physical map spanning the region comprising 24 overlapping BACs. Eighteen of these BACs have been fully sequenced, or are in draft form, allowing us to annotate approximately 2.5 Mb of DNA surrounding the jsd locus. The critical 0.4 cM jsd interval corresponds to a physical distance of approximately 1.5 Mb. Eight genes have been identified in this interval, two of which appear to be possible candidates for the jsd mutation.

Testosterone suppresses spermatogenesis in juvenile spermatogonial depletion (jsd ) mice

Male juvenile spermatogonial depletion (jsd/jsd) mice are sterile because of a failure of spermatogonial differentiation. We have previously reported the recovery of spermatogonial differentiation by suppressing the levels of gonadotropins and testosterone with Nal-Glu, a GnRH antagonist. To determine whether suppression of testosterone or the gonadotropins was responsible for spermatogenic recovery, we examined the effect of supplementation of LH or FSH along with Nal-Glu treatment. Systemic administration of flutamide, an androgen receptor antagonist, was also examined. LH supplementation elevated both serum and intratesticular testosterone levels and suppressed the recovery of spermatogonial differentiation in a dose-dependent manner. Supplementation with FSH did not affect either testosterone levels or spermatogonial differentiation. Furthermore, the mice treated with flutamide showed some recovery of spermatogonial differentiation. The overall findings revealed that testosterone action mediated by androgen receptors suppressed the spermatogonial differentiation in jsd/jsd mice and suggested that spermatogonial differentiation in the jsd mutant is highly sensitive to testosterone suppression.

Defect in germ cells, not in supporting cells, is the cause of male infertility in the jsd mutant mouse: proliferation of spermatogonial stem cells without differentiation

C57BL/6 (B6)-jsd/jsd male mice are sterile because of lack of spermatogenesis. To find the cause of the deficient spermatogenesis, we have examined whether the mutation phenotype is the result of a defect in germ cells or in supporting cells using germ cell transplantation. In the seminiferous tubules of B6-jsd/jsd mutant mice, donor germ cells derived from the wild type GFP transgenic mouse (B6-+/+GFP) were able to undergo complete spermatogenesis, indicating that the juvenile spermatogonial depletion (jsd/jsd) mouse possesses normal supporting cell functions. In contrast, undifferentiated spermatogonia derived from B6-jsd/jsd mice were unable to differentiate in the seminiferous tubules of W/W v mice, even if the mutant germ cells successfully settled in the tubules. These results demonstrate that the deficiency in spermatogenesis of B6-jsd/jsd mice can be ascribed to a defect in spermatogonia but not in their supporting cell environment. Furthermore, the defect in B6-jsd/jsd spermatogonia is not in their ability to proliferate, but in their differentiation and may result from their hypersensitivity to high concentrations of androgen in the testis.

Regulation of proliferation and differentiation in spermatogonial stem cells: the role of c-kit and its ligand SCF

To study self-renewal and differentiation of spermatogonial stem cells, we have transplanted undifferentiated testicular germ cells of the GFP transgenic mice into seminiferous tubules of mutant mice with male sterility, such as those dysfunctioned at Steel (Sl) locus encoding the c-kit ligand or Dominant white spotting (W) locus encoding the receptor c-kit. In the seminiferous tubules of Sl/Sl(d) or Sl(17H)/Sl(17H) mice, transplanted donor germ cells proliferated and formed colonies of undifferentiated c-kit (−) spermatogonia, but were unable to differentiate further. However, these undifferentiated but proliferating spermatogonia, retransplanted into Sl (+) seminiferous tubules of W mutant, resumed differentiation, indicating that the transplanted donor germ cells contained spermatogonial stem cells and that stimulation of c-kit receptor by its ligand was necessary for maintenance of differentiated type A spermatogonia but not for proliferation of undifferentiated type A spermatogonia. Furthermore, we have demonstrated that their transplantation efficiency in the seminiferous tubules of Sl(17H)/Sl(17H) mice depended upon the stem cell niche on the basement membrane of the recipient seminiferous tubules and was increased by elimination of the endogenous spermatogonia of mutant mice from the niche by treating them with busulfan.

Stimulation of spermatogonial differentiation in juvenile spermatogonial depletion (jsd) mutant mice by gonadotropin-releasing hormone antagonist treatment

Male juvenile spermatogonial depletion (jsd) mutant mice are sterile because of spermatogenic failure and so may provide a model for genetically caused human male infertility. To test the effects of testosterone suppression therapy on spermatogenesis in jsd/jsd mice, we treated them with Nal-Glu, a GnRH antagonist. Treatment with Nal-Glu at 2500 microg/kg/day was started at 5.5 or 8 weeks of age and continued for 4 or 8 weeks. Differentiation of spermatogonia was evaluated by the percentage of tubules containing two or more spermatocytes (% of differentiating tubules). Nal-Glu treatment caused a marked decrease in the weights of the testes and seminal vesicles and intratesticular testosterone concentrations. However, in contrast to a value of 1.3% in untreated jsd/jsd mice, the mean % of differentiating tubules was 59.9% and 25.1% in treatment groups started at 5.5 and 8 weeks of age, respectively. We propose that spermatogonial differentiation in jsd/jsd mutant mice is sensitive to the high intratesticular levels of testosterone and can only proceed when testosterone production is suppressed.

Stage-specific localization of basigin, a member of the immunoglobulin superfamily, during mouse spermatogenesis

Ablation of the transmembrane glycoprotein basigin leads to azoospermic mice, indicating that this gene is essential for spermatogenesis. To examine the functions of basigin in the testis, the precise localization of basigin during spermatogenesis was examined immunohistochemically. In the adult mouse testis, basigin immunoreactivity appeared on the cell surface of leptotene spermatocytes and gradually increased in intensity during the meiotic prophase. Cytoplasmic staining, as well as cell surface staining, was detected in spermatids. The most conspicuous reactivity was found in the spermatids at steps 9-11 and in the flagella of spermatids. Immuno-electron microscopic analysis demonstrated that basigin was localized not only on the plasma membranes of spermatocytes and spermatids, but also on the plasma membrane of the Sertoli cell processes which contact the spermatocytes and spermatids. Basigin immunoreactivity was also detected during postnatal development in spermatocytes and spermatids but not in spermatogonia. Experimental cryptorchid testes which contain only spermatogonia and Sertoli cells in the seminiferous epithelium showed no basigin immunoreactivity. Seven days after surgical reversal of the cryptorchid testis, spermatocytes reappeared in the tubules, along with basigin immunoreactivity. Furthermore, in sterile mutant mice, in which neither spermatocytes nor spermatids were generated, no basigin immunoreactivity was detected in the seminiferous tubules. These findings indicate that expression of basigin is concomitant with appearance of spermatocytes in the seminiferous tubule, and suggest that basigin is involved in the interaction between Sertoli cells and germ cells at specific stages of spermatogenesis.

Coexpression of multiple Sertoli cell and Leydig cell marker genes in the spontaneous testicular tumor of F344 rat: evidence for phenotypical bifurcation of the interstitial cell tumor

The development of testicular tumor has been frequently observed in some laboratory rat strains. In the present study, we have further characterized the testicular tumor that spontaneously develops in the F344 rat (F344/Jcl). Tumor cells first appeared in the interstitium and developed into multifocal nodular lesions. In the later stage, the whole testes were occupied by tumor cells that consisted of three different types of cells in morphological appearance: large clear type, small eosinophilic type and intermediate type. To determine the character of these cells, we examined the expression of marker genes for Sertoli cells (e.g., transferrin) and Leydig cells (e.g., 3 beta-hydroxysteroid dehydrogenase 1 (3 beta-HSD 1)). Transferrin and 3 beta-HSD 1 mRNAs were found in all 8 tumor samples analyzed by northern blotting. By in situ hybridization, we observed a substantial amount of 3 beta-HSD 1 mRNA and little or no transferrin mRNA in the large clear cells. In contrast, the small eosinophilic cells showed little or no 3 beta-HSD 1 mRNA and a large amount of transferrin mRNA, suggesting that the tumor was a mixture of at least two types of cells. Other Sertoli cell marker genes, such as cyclic protein 2 and sulfated glycoprotein 2, were expressed in all 8 tumors analyzed, and testin and steel factor (SLF), the c-kit receptor ligand, were also expressed in some of the tumors (testin, 75%; SLF, 25%), while other Leydig cell markers, LH receptor and c-kit, were expressed in 87% and 80% of the tumors, respectively. These results indicate that the spontaneous testicular tumor of F344 rat is of interstitium origin, showing phenotypical bifurcation possibly via transdifferentiation.

Cessation of spermatogenesis in juvenile spermatogonial depletion (jsd/jsd) mice

BACKGROUND

Mice homozygous for the jsd (juvenile spermatogonial depletion) allele are sterile because they become azoospermic. The onset of such azoospermia was investigated by histologic analysis of sections of testes from jsd/jsd mice.

METHOD

The testes removed from C57BL/6-jsd/jsd mice aged 3 to 10 weeks were examined microscopically.

RESULTS

At 3 weeks of age, spermatocytes were seen in most of the seminiferous tubules of jsd/jsd mice. However, the number of tubules that contained spermatids was significantly smaller than that counted in the wild-type mice. Since degenerative figures were not abundant in the jsd/jsd testes, the decreased number of spermatids found in the tubules suggested a longer duration of development from spermatocyte to spermatid in jsd/jsd mice. The abnormality extended to the development of type B spermatogonia, and a decrease in their number became apparent after 6 weeks of age in most of the jsd/jsd tubules. However, as early as 3 weeks of age, a few seminiferous tubules in jsd/jsd mice already contained only Sertoli cells and type A spermatogonia.

CONCLUSION

It is assumed that the decrease in type B spermatogonia occurred at various ages and locations. The defect of spermatogenesis in jsd/jsd mice was attributable to aberrations in multiple steps of spermatogenesis.

Characterization of a novel spermatogenic cell antigen specific for early stages of germ cells in mouse testis

To study the mechanism of spermatogenesis during the premeiotic phase, a hybridoma producing monoclonal antibody (mAb) specific for early stages of spermatogenic cells was obtained. In immunohistochemical staining of adult testis, this mAb, designated as EE2, was able to react with type A to B spermatogonia and early meiotic cells, but not with Sertoli cells, Leydig cells, and other somatic tissues. Precursor cells of type A spermatogonia (gonocytes) were also positive for EE2 in perinatal mouse testis. The antigenic molecule recognized by mAb EE2 was a novel glycoprotein with molecular weight of 114 kDa, which had affinity with Con A and WGA lectins, and was susceptible to N-glycanase, suggesting the presence of asparagine-linked sugar chains. Furthermore, EE2 antigen was found to localize on the germ cell surface. The specific expression of this antigenic molecule suggests that it may play an important role in early spermatogenesis, of which only a little information is available at present.

Protection against hantavirus infection by dam's immunity transferred vertically to neonates

Antibodies to hantavirus, Seoul type B-1 strain, vertically transferred to rat neonates prevented lethal as well as persistent infection. When relatively high titer viruses were inoculated into neonates, the mother's antibodies protected all the neonates from lethal virus infection. However, the antibodies could not protect all of the neonates from persistent infection but only half of them underwent persistent infection. The other half was completely cured but also became persistently infected when rechallenged with the active viruses after reaching maturity.

Experimental transmission of hantavirus infection in laboratory rats

This study found a competent transmission of hantavirus between cagemates using congenitally T cell-deficient Rowett nude rats (rnu/rnu). Intraperitoneally infected immunologically normal rats (rnu/+) did not transmit the hantavirus to their normal cagemates (rnu/+) but did to Rowett nude rats (rnu/rnu). Thus, nude rats were shown to be highly susceptible to the hantavirus infection. Also, infected nude rats (rnu/rnu) discharged the infectious viruses, to cause a prevalence of infection among normal cagemates (rnu/+). The infection system demonstrated here using Rowett rats (rnu/rnu) may provide a useful model to study the mechanism of the hantavirus infection.

In utero and mammary transfer of hantavirus antibody from dams to infant rats

The effects of maternal-infant transfer of specific antibody on infection attributable to hemorrhagic fever with renal syndrome-causing virus in the infant rat were studied. In cross-fostering experiments, maternal hantavirus-specific antibody was shown to be transferred equally effectively to infants either in utero or by breastfeeding. Both IgG- and IgA-specific antibodies were transferred. Infected infants that initially acquired high levels of maternal antibodies by either route survived lethal doses of the virus and did not show any signs of disease. Furthermore, 15 weeks later, these animals had no evidence of remaining antibodies or viral infection. These results indicate that maternal antibody, transferred to the infant rat in utero or by breastfeeding, is protective against hantavirus infection.

Infection of Nippostrongylus brasiliensis induces normal increase of basophils in mast cell-deficient Ws/Ws rats with a small deletion at the kinase domain of c-kit

All basophils, mucosal-type mast cells (MMC) and connective tissue-type mast cells (CTMC) are derived from the multipotential hematopoietic stem cell. Mutations at the c-kit locus resulted in deficiency of MMC and CTMC in both mice and rats. To investigate the role of the c-kit receptor tyrosine kinase for production of basophils, we used white spotting/white spotting (Ws/Ws) mutant rats that have a small deletion at the tyrosine kinase domain of the c-kit gene. When Ws/Ws, nude athymic, and normal (+/+) rats were infected with Nippostrongylus brasiliensis (NB), the number of basophils increased greater than 50-fold in the peripheral blood of Ws/Ws and +/+ rats but did not increase in that of nude rats. Blood histamine concentration increased significantly in Ws/Ws and +/+ rats but did not increase in nude rats. Immature basophils increased greater than 10-fold in the bone marrow of Ws/Ws and +/+ rats but did not increase in that of nude rats. Mature and immature basophils that developed after the NB infection were identified by electron microscopy. The present result confirms that T-cell-derived cytokines are indispensable for the augmented production of basophils and suggests that stimulation via the c-kit receptor may not be necessary for the augmented production.

Loss of sperm in juvenile spermatogonial depletion (jsd) mutant mice is ascribed to a defect of intratubular environment to support germ cell differentiation

C57BL/6(B6)-jsd/jsd mice are sterile due to the defective spermatogenesis in the testes. To know the cause of the deficient spermatogenesis in B6-jsd/jsd mice, we examined whether the problem is within or outside the seminiferous tubules by transplanting tubules from cryptorchid testes of B6- +/+ mice into B6-jsd/jsd testes or tubules from B6-jsd/jsd mice into testes of (WB x C57BL/6)F1-W/Wv (hereafter, WBB6F1-W/Wv) mice. Type A spermatogonia differentiated into spermatids in seminiferous tubules from cryptorchid testes transplanted into B6-jsd/jsd testes. In contrast, in B6-jsd/jsd tubules transplanted into WBB6F1-W/Wv testes, type A spermatogonia were stimulated to mitotic proliferation, but didn't proceed to any differentiated germ cells. The present results suggest that the cause of the deficient spermatogenesis in B6-jsd/jsd mice is a defect of intratubular environment to support germ cell differentiation.

Anemia and mast cell depletion in mutant rats that are homozygous at "white spotting (Ws)" locus

Mice possessing two mutant alleles at the W or Sl locus are anemic and deficient in mast cells. These mouse mutants have black eyes and white hair. Because homozygous mutant rats at the newly found white spotting (Ws) locus were also black-eyed whites, the numbers of erythrocytes and mast cells were examined. Suckling Ws/Ws rats showed a severe macrocytic anemia and were deficient in mast cells. When bone marrow cells of normal (+/+) control or Ws/Ws rats were injected into C3H/He mice that had received cyclophosphamide injection and whole-body irradiation, remarkable erythropoiesis occurred in the spleen of +/+ marrow recipients but not in the spleen of Ws/Ws marrow recipients. When skin pieces of Ws/Ws embryos were grafted under the kidney capsule of nude athymic rats, mast cells did develop in the grafted skin tissues. Therefore, the anemia and mast cell deficiency of Ws/Ws rats were attributed to a defect of precursors of erythrocytes and mast cells. Because the magnitude of the anemia decreased and that of the mast cell deficiency increased in adult Ws/Ws rats, this mutant is potentially useful for investigations about differentiation and function of mast cells.

Neural crest origin of clear cell sarcoma of tendons and aponeuroses. Ultrastructural and enzyme cytochemical study of human and nude mouse-transplanted tumours

In order to clarify the histogenesis of clear cell sarcoma of tendons and aponeuroses (CCS), two cases of human and one nude mouse-transplanted CCS line were studied using an ultrastructural and enzyme cytochemical approach. Most of the tumour cells obtained from the primary and transplanted CCS demonstrated melanosomes in various stages of development within the cytoplasm, whereas no melanosomes could be identified in the metastatic CCS. However, cholinesterase and tyrosinase activities could be demonstrated not only in the melanotic primary and transplanted CCS but also in the amelanotic metastatic CCS. The results therefore support the hypothesis that CCS is a soft tissue tumour derived from the neural crest.

Control of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) in Japan

By the end of 1985, 126 human cases of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) were recorded in Japan. Seroepidemiological studies revealed that laboratory rats exhibited high IFA titers against Hantaan or related viruses at locations where HFRS patients occurred. Laboratory researchers contracted HFRS more frequently than laboratory animal technicians or caretakers, although a laboratory animal caretaker died of the disease. Inhalation of HFRS-virus contaminated air in an animal facility is the likely cause of infection with this virus. Wound infection during animal experiments may be another important route of infection. Infection of laboratory rats can occur by transferring animals from contaminated to other animal facilities. Tissue fragments or cells of transplantable animal tumors are a potential source of spreading the HFRS virus. Eradication of HFRS virus from a contaminated animal facility can be achieved best by elimination of all animals in the room, especially when human HFRS is associated with an infected colony. In some cases, when IFA titers of the sera of the rats tested were low, infection apparently disappeared without instituting any particular control measures other than ordinary procedures for care and management of laboratory animals. HFRS viruses have not yet been eradicated from all animal facilities in Japan. Therefore, serological monitoring of laboratory rats continues.