scholarly journals Spermatogonial morphology and kinetics during testis development in mice: a high-resolution light microscopy approach

Reproduction ◽  
2011 ◽  
Vol 142 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Ana Luiza Drumond ◽  
Marvin L Meistrich ◽  
Hélio Chiarini-Garcia
Keyword(s):  
High Resolution ◽  
Light Microscopy ◽  
Type A ◽  
Absolute Number ◽  
Morphological Development ◽  
Type B ◽  
Developmental Sequence ◽  
Adult Mice ◽  
Pathological Conditions ◽  
Type A Spermatogonia

Despite the knowledge of spermatogonial biology in adult mice, spermatogonial development in immature animals has not been fully characterized. Thus, the aim of this study was to evaluate the ontogeny of the morphological development of the spermatogonial lineage in C57BL/6 mouse testis, using high-resolution light microscopy. Spermatogonial morphology, chronology, and absolute number were determined for different ages postpartum (pp). The morphology of spermatogonia in immature mice was similar to that of adult spermatogonia, although their nuclear diameter was slightly smaller. The A1 spermatogonia were first observed on day 2 pp, and only 24 h later, differentiating type A3 and A4 spermatogonia were observed in the seminiferous cords. This result indicated a shortening of the spermatogonial phase for immature mice of about ∼2.5 days when compared with adult mice and suggests that gonocytes and/or A1 spermatogonia could directly become A4 spermatogonia, skipping the developmental sequence of type A spermatogonia. These A4 spermatogonia are functional as they develop into type B spermatogonia by day 5 pp. At day 8 pp, while differentiation to spermatocytes begins, the Aund spermatogonia reach their maximal numbers, which are maintained through adulthood. The various details of the spermatogonial behavior in immature normal mice described in this study can be used as a baseline for further studies under experimental or pathological conditions.

Vibrational Analysis of the 2800 Å Band System of para-Dibromobenzene

1972 ◽  
Vol 50 (12) ◽  
pp. 1402-1408 ◽  
Author(s):  
S. M. Japar
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Ground State ◽  
Band System ◽  
Vibrational Analysis ◽  
Type A ◽  
Strong Type ◽  
Type B ◽  
Sequence Structure ◽  
Extensive Sequence

The 2800 Å band system of p-dibromobenzene has been photographed under high resolution and an extended vibrational analysis has been carried out. The analysis is not inconsistent with the assignment of the system to a 1B2u ← 1Ag transition, by analogy with other p-dihalogenated benzenes. The observed spectrum can be explained in terms of a number of strong type-B vibronic bands and a considerably smaller number of type-A vibronic bands. The extensive sequence structure is adequately accounted for, and can be related to observations on other halogenated benzene molecules. Thirteen ground state and nine excited state fundamental vibrational frequencies have been assigned.

The population of germ cells in immature male rats following irradiation at birth

1966 ◽  
Vol 165 (998) ◽  
pp. 103-135 ◽  
Keyword(s):  
Germ Cells ◽  
Total Population ◽  
Primordial Germ Cells ◽  
Type A ◽  
Male Rats ◽  
Type B ◽  
The Absolute ◽  
The Difference ◽  
Transitional Cells ◽  
Type A Spermatogonia

Male rats were irradiated with 19 r on the day of birth, and killed at intervals ranging from 5 to 18 days. Estimates were made of the absolute and relative numbers of germ cells at different stages of spermatogenesis in 64 irradiated and 61 untreated specimens. In the normal rat, the calculated population of germ cells increased from about 160000 at 5 days to 30 million at 18 days. Only negligible numbers of primordial germ cells (gonocytes and transitional cells) persisted beyond the age of 10 days. Small numbers of spermatogonia type A appeared at 5 days (15000) and their population rose to about 1 million at 12 days, and 2 million at 18 days (7 % of all germ cells). Intermediate spermatogonia first occurred in appreciable numbers (23000 to 55000) at 8 or 9 days, when the population of type-A spermatogonia was 360000. The subsequent rise in the population of intermediate spermatogonia was more rapid than that of type A (4 million at 18 days). Spermatogonia type B and primary spermatocytes appeared at 9 to 10 days, and their numbers rose more steeply still (6.5 and 16 million at 18 days, respectively). Irradiation at birth exerted no rapid effect on the cytological appearance of primordial germ cells. Transformation from gonocytes to transitional cells appeared to proceed normally and the estimated total population of germ cells at 5 days was no smaller than in the controls. Subsequently, however, many of the transitional cells failed to divide: they enlarged to form giant cells, acquired bizarre nuclear outlines, and persisted for unusually long periods. Some degenerated at mitotic prophase or metaphase, while a few seemed to die at interphase, without entering division. The calculated total population of germ cells in irradiated rats rose from 160000 at 5 days to 9.4 million at 18 days. Small numbers of spermatogonia type A, presumably derived from such primordial germ cells as were able to complete mitosis, appeared some 2 to 3 days later than in controls. The number of type-A spermatogonia in 7-day-old irradiated rats was 44000, cf. 215000 in controls; the difference became less pronounced with time, and by the age of 18 days, the population of 1.9 million was comparable to that estimated for the controls. Small numbers of intermediate spermatogonia appeared on the 9th (8000) and 10th day (35000), when the population of type-A spermatogonia was about 110000 and 260000 respectively. By the 18th day, intermediate spermatogonia numbered 2 million. The populations of type-B spermatogonia and primary spermatocytes rose from 11000 to 13000 at 10 days to 1.6 and 3.4 million, respectively, at 18 days. The difference in the absolute and relative numbers of germ cells between normal and irradiated testes widened progressively with advance in the developmental stage of the germ cells. Analysis of the results indicates that in the reduced population of spermatogonia type A after irradiation, the pattern of spermatogonial mitoses is modified so as to favour the formation of more type-A, in preference to intermediate, spermatogonia.

Role of c-kit in mouse spermatogenesis: identification of spermatogonia as a specific site of c-kit expression and function

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 689-699 ◽  
Author(s):  
K. Yoshinaga ◽  
S. Nishikawa ◽  
M. Ogawa ◽  
S. Hayashi ◽  
T. Kunisada ◽  
...  
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Type A ◽  
Tyrosine Kinase Receptor ◽  
Postnatal Life ◽  
Adult Mice ◽  
Undifferentiated Type ◽  
Type A Spermatogonia

Recent studies have shown that the dominant white spotting (W) locus encodes the proto-oncogene c-kit, a member of the tyrosine kinase receptor family. One symptom of mice bearing mutation within this gene is sterility due to developmental failure of the primordial germ cells during early embryogenesis. To elucidate the role of the c-kit in gametogenesis, we used an anti-c-kit monoclonal antibody, ACK2, as an antagonistic blocker for c-kit function to interfere with the development of male and female germ cells during postnatal life. ACK2 enabled us to detect the expression of c-kit in the gonadal tissue and also to determine the functional status of c-kit, which is expressed on the surface of a particular cell lineage. Consistent with our immunohistochemical findings, the intravenous injection of ACK2 into adult mice caused a depletion in the differentiating type A spermatogonia from the testis during 24–36 h, while the undifferentiated type A spermatogonia were basically unaffected. Intraperitoneal injections of ACK2 into prepuberal mice could completely block the mitosis of mature (differentiating) type A spermatogonia, but not the mitosis of the gonocytes and primitive type A spermatogonia, or the meiosis of spermatocytes. Our results indicate that the survival and/or proliferation of the differentiating type A spermatogonia requires c-kit, but the primitive (undifferentiated) type A spermatogonia or spermatogenic stem cells are independent from c-kit. Moreover, the antibody administration had no significant effect on oocyte maturation despite its intense expression of c-kit.

scholarly journals Spermatogenic cells of the prepuberal mouse: isolation and morphological characterization

1977 ◽  
Vol 74 (1) ◽  
pp. 68-85 ◽  
Author(s):  
AR Bellve ◽  
JC Cavicchia ◽  
CF Millette ◽  
DA O'Brien ◽  
YM Bhatnagar ◽  
...  
Keyword(s):  
Sertoli Cells ◽  
Morphological Characteristics ◽  
Type A ◽  
Cell Types ◽  
Specific Cell ◽  
Spermatogenic Cells ◽  
Type B ◽  
Primitive Type ◽  
Pachytene Spermatocytes ◽  
Type A Spermatogonia

A procedure is described which permits the isolation from the prepuberal mouse testis of highly purified populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene primary spermatocytes, leptotene and zygotene primary spermatocytes, pachytene primary spermatocytes and Sertoli cells. The successful isolation of these prepuberal cell types was accomplished by: (a) defining distinctive morphological characteristics of the cells, (b) determining the temporal appearance of spermatogenic cells during prepuberal development, (c) isolating purified seminiferous cords, after dissociation of the testis with collagenase, (d) separating the trypsin-dispersed seminiferous cells by sedimentation velocity at unit gravity, and (e) assessing the identity and purity of the isolated cell types by microscopy. The seminiferous epithelium from day 6 animals contains only primitive type A spermatogonia and Sertoli cells. Type A and type B spermatogonia are present by day 8. At day 10, meiotic prophase is initiated, with the germ cells reaching the early and late pachytene stages by 14 and 18, respectively. Secondary spermatocytes and haploid spermatids appear throughout this developmental period. The purity and optimum day for the recovery of specific cell types are as follows: day 6, Sertoli cells (purity>99 percent) and primitive type A spermatogonia (90 percent); day 8, type A spermatogonia (91 percent) and type B spermatogonia (76 percent); day 18, preleptotene spermatocytes (93 percent), leptotene/zygotene spermatocytes (52 percent), and pachytene spermatocytes (89 percent), leptotene/zygotene spermatocytes (52 percent), and pachytene spermatocytes (89 percent).

Hormones and the differentiation of type A spermatogonia in mouse cryptorchid testes incubated in vitro

1982 ◽  
Vol 94 (1) ◽  
pp. 43-NP ◽  
Author(s):  
Tatsuji Haneji ◽  
Yoshitake Nishimune
Keyword(s):  
Cell Differentiation ◽  
Germ Cell ◽  
Cyclic Adenosine Monophosphate ◽  
Type A ◽  
Adenosine Monophosphate ◽  
Testicular Germ Cell ◽  
Adult Mice ◽  
Germ Cell Differentiation ◽  
Type A Spermatogonia

In order to study hormonal effects on testicular germ cell differentiation, especially on type A spermatogonia, artificially induced cryptorchid testes of adult mice were cultured in a medium containing testosterone, dihydrotestosterone, tri-iodothyronine, dibutyryl 3′: 5′ cyclic adenosine monophosphate, human chorionic gonadotrophin, LH, FSH, insulin and transferrin. These substances, with the exception of FSH, showed no stimulatory effect on the differentiation of type A spermatogonia. However, FSH activated cell division in type A spermatogonia and stimulated them to differentiate, while LH showed neither the promotion of differentiation nor a synergistic effect on FSH-mediated germ cell differentiation.

RESPONSE OF MALE GERM CELLS OF MOUSE TO ACUTE AND FRACTIONATED DOSES OF 131I INDUCED RADIATION

1982 ◽  
Vol 24 (6) ◽  
pp. 817-820 ◽  
Author(s):  
P. P. Reddy ◽  
S. B. Reddy ◽  
D. N. Ebenezer ◽  
O. S. Reddi
Keyword(s):  
Survival Rate ◽  
B Cells ◽  
Germ Cells ◽  
Dose Group ◽  
Radioactive Iodine ◽  
Type A ◽  
Type B ◽  
Survival Fraction ◽  
Male Germ Cells ◽  
Type A Spermatogonia

The effects of radioactive iodine in acute as well as fractionated doses on male germ cells were studied. 131I in four acute doses of 10, 15, 20 and 25 μCi was given intraperitoneally. For fractionated doses, 12.5 μCi was given twice with an interval of 24 h. A dose relationship was exhibited between the concentration of radionuclide and the survival fraction of type A spermatogonia, intermediate and type B spermatogonia and preleptotene spermatocytes. The maximum depletion was recorded after 25 μCi. The survival values for this dose group were 40.4, 51.4, and 25.0% for type A cells, intermediate and type B cells and preleptotene spermatocytes, respectively. Fractionated doses of radioiodine also reduced the survival rate of gonadal cells and are more effective than 20 μCi acute dose in decreasing the survival fraction of all types of gonadal cells.

scholarly journals Stage-Specific Expression of CYP26B1 in the Adult Testis is Responsible for Pulsatile Retinoic Acid Signaling in Spermatogenesis

2017 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Retinoic Acid ◽  
Expression Pattern ◽  
Type A ◽  
Seminiferous Epithelium ◽  
Type B ◽  
Specific Expression ◽  
Adult Testis ◽  
Undifferentiated Type ◽  
Meiotic Initiation ◽  
Type A Spermatogonia

Retinoic acid (RA) plays important roles in spermatogenesis process; however, mechanisms underlying pulsatile RA signaling in meiotic initiation has not been understood yet. We studied expression pattern of RA-degrading enzyme CYP26B1 during development of rhesus monkey testis using qPCR and IHC. In developing monkey testis, the CYP26B1 protein was detected in cytoplasm of undifferentiated spermatogonia. Expression level of CYP26B1 mRNA was down-regulated during testis development which is consistent with initiation of meiosis in adult testis. In adult testes, a heterogeneous pattern of CYP26B1 expression was observed along different stages of seminiferous epithelium, presumably indicates expression pattern of protein is stage specific. Highest level of CYP26B1 protein expression was coincided with onset of meiosis and observed in early meiotic spermatocytes within seminiferous epithelial stages X-XII. Whereas, lowest level of CYP26B1 expression was observed in stages VI-IX of seminiferous epithelium, where undifferentiated Type A spermatogonia divide and differentiate to Type B spermatogonia, meiosis initiates and spermiogenesis occurs. This observations led us to suggest CYP26B1 might be responsible for pulsatile RA signaling in spermatogenesis. Findings presumably support that elevated amount of RA in undifferentiated Type A spermatogonia during stages VI-IX of the seminiferous epithelium of adult monkey testis may be responsible for differentiation of spermatogonia and their meiotic entry

Examination of Schistosome Cercariae and Schistosomules by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 50-51
Author(s):  
D. Johnson ◽  
P. Moriearty
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Light Microscopy ◽  
Surface Structure ◽  
Extensive Study ◽  
Scanning Microscopy ◽  
Host Parasite ◽  
Conventional Electron Microscopy ◽  
Scanning Electron

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.

Biological and Morphological Studies on Low-Leukemia-Strain Mice with Hodgkin's-Like Neoplasia Induced by Serial Cell-Free Transmission of Leukemic Organs of SJL/J Strain Mice

1968 ◽  
Vol 26 ◽  
pp. 210-211
Author(s):  
S. Fujinaga ◽  
K. Maruyama ◽  
C.W. Williams ◽  
K. Sekhri ◽  
L. Dmochowski
Keyword(s):  
Tissue Culture ◽  
Type A ◽  
Reticulum Cell ◽  
Type B ◽  
Viral Origin ◽  
Serial Transfer ◽  
Strain Mouse ◽  
Morphological Studies ◽  
Cell Neoplasm ◽  
Free Material

Yumoto and Dmochowski (Cancer Res.27, 2098 (1967)) reported the presence of mature and immature type C leukemia virus particles in leukemic organs and tissues such as lymph nodes, spleen, thymus, liver, and kidneys of SJL/J strain mice with Hodgki's-like disease or reticulum cell neoplasm (type B). In an attempt to ascertain the possibility that this neoplasia may be of viral origin, experiments with induction and transmission of this neoplasm were carried out using cell-free extracts of leukemic organs from an SJL/J strain mouse with spontaneous disease.It has been possible to induce the disease in low-leukemia BALB/c and C3HZB strain mice and serially transfer the neoplasia by cell-free extracts of leukemic organs of these mice. Histological examination revealed the neoplasia to be of either reticulum cell-type A or type B. Serial transfer is now in its fifth passage. In addition leukemic spleen from another SJL/J strain mouse with spontaneous reticulum cell neoplasm (type A) was set up in tissue culture and is now in its 141st serial passage in vitro. Preliminary results indicate that cell-free material of 39th tissue culture passage can reproduce neoplasia in BALB/c mice.

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

1995 ◽  
Vol 53 ◽  
pp. 692-693
Author(s):  
Yun Lu ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Morphological Development ◽  
Early Hydration ◽  
X Ray ◽  
Blended Cements ◽  
Powder Particles ◽  
Chemical Wastes ◽  
Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

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