Safety and immunogenecity of a live attenuated Rift Valley fever vaccine (CL13T) in camels

Background

Rift Valley fever is an emerging zoonotic viral disease, enzootic and endemic in Africa and the Arabian Peninsula, which poses a significant threat to both human and animal health. The disease is most severe in ruminants causing abortions in pregnant animals, especially sheep animals and high mortality in young populations. High mortality rates and severe clinical manifestation have also been reported among camel populations in Africa, to attend however none of the currently available live vaccines against RVF have been tested for safety and efficacy in this species. In this study, the safety and efficacy (through a neutralizing antibody response) of the thermostable live attenuated RVF CL13T vaccine were evaluated in camels in two different preliminary experiments involving 16 camels, (that 12 camels and 4 pregnant camels).

Results

The study revealed that the CL13T vaccine was safe to use in camels and no abortions or teratogenic effects were observed. The single dose of the vaccine stimulated a strong and long-lasting neutralizing antibody response for up to 12 months.

Conclusion

The presence of neutralization antibodies is likely to correlate with protection; however protection would need to be confirmed by challenge experiments using the virulent RVF virus.

African horse sickness outbreaks caused by multiple virus types in Ethiopia

African horse sickness (AHS) is associated with high morbidity and mortality in equids, especially horses. A retrospective analysis was carried out concerning 737 AHS outbreaks that occurred during 2007-2010 in Ethiopia. A total of ten outbreaks were investigated in the study period. All four forms of the disease (pulmonary, cardiac, horse sickness fever and the combined form) were observed, with the cardiac form being the most prevalent. Multiple African horse sickness virus serotypes (AHSV-2, AHSV-4, AHSV-6, AHSV-8 and AHSV-9) were detected by molecular methods (type-specific real-time RT-PCR assays), and fourteen isolates were derived from blood and tissue samples collected during 2009-2010. This is the first report of AHSV-4, AHSV-6 or AHSV-8 in Ethiopia.

Emergence of bluetongue serotypes in Europe, part 2: the occurrence of a BTV-11 strain in Belgium

An EDTA-blood sample from a cow without clinical signs, which gave early birth to a newborn calf that died soon after delivery, was shown to be positive for bluetongue virus (BTV)-RNA using a group-specific real-time RT-PCR (RT-qPCR). In-house serotype-specific RT-qPCR assays for bluetongue virus serotype 1 (BTV-1), -6 and -8 all gave negative results. Subsequent assays were carried out using conventional (gel-based) RT-PCR primers for all 25 BTV serotypes and only two primer sets, both specific for BTV-11, gave bands of the expected size. The cDNAs generated were sequenced and comparisons of the genome segment 2 sequence with that of the modified 'live' vaccine strain of BTV-11 from South Africa showed 100% identity. A survey of all ruminants in a 1-km area around the first positive farm using a BTV-11 serotype-specific RT-qPCR revealed five other holdings with in total nine BTV-11 positive animals. A cross-sectional monitoring of dairy cattle in Belgium showed an overall prevalence of 3.8% on herd level and 0.2% on animal level. A BTV-11 has been introduced into the Belgian cattle herd during the 2008 vector season. The source of the infection and the way by which the virus was introduced are unknown.

African swine fever virus: a B cell-mitogenic virus in vivo and in vitro

The two major characteristics of pathogenesis in African swine fever virus (ASFV) infections of domestic pigs are massive B-cell apoptosis and haemorrhage. The effects of ASFV on porcine B cells have therefore been systematically examined in vivo, by using virus-infected pigs and SCID-Beige mice reconstituted with porcine bone marrow, and in vitro, by using porcine B-cell lines and B cells from normal and ASFV-infected pigs. Secretion of porcine Ig was stimulated by ASFV both in vivo and in bone marrow cultures in vitro, with the virulent Malawi isolate of ASFV being the most effective. Stimulation of Ig secretion in vitro depended on the presence of ASFV-infected macrophages and did not occur with supernatants from ASFV-infected macrophages. Although the virus alone did not stimulate proliferation of purified B cells in vitro, it was co-stimulatory with CD154 (CD40 ligand). The B cells recovered from ASFV-infected porcine lymphoid tissue were of activated surface marker phenotypes and, interestingly, expressed diminished levels of the B-cell co-stimulatory surface molecule CD21. In addition, they were highly sensitive to IL-4 and CD154. These results may be integrated into a model of pathogenesis in which those B cells activated indirectly as a result of virulent ASFV infection of macrophages are not rescued from apoptosis through interaction with CD154, due to the drastic depletion of T cells that occurs early in infection. The consequently diminished specific anti-ASFV antibody response would favour survival of the virus, with the non-specific hypergammaglobulinaemia being perhaps another example of pathogen-mediated immune deviation.

Fine structural changes in the postacrosomal region of the hamster and mouse sperm head at the initial stage of gamete interaction in vivo

This report documents ultrastructural changes in the postacrosomal region of the hamster and mouse sperm head at the initial stage of gamete interaction in vivo. Prominent structures were sequentially visualized: first, the periodic substructure crossbridging the postacrosomal sheath to the overlying plasma membrane, and then the small, electron-dense, granular structures lining the outer surface of the postacrosomal sheath. The periodic substructure became visible at the restricted region where the sperm plasma membrane was just prior to or in the act of detaching from the periodic substructure. The granular substances lined up along the external face of the postacrosomal sheath immediately after the detachment of the sperm plasma membrane, but before the complete degradation of the periodic substructure. These structural changes were completed before sperm nuclear decondensation started. The region where the granular structures were visualized was close to that of the antigen recognized by the monoclonal antibody MN13, which is supposed to be involved in the association of the periodic substructure with the overlaying plasma membrane (Toshimor et al., 1991). Based upon these results, we present the progress of events at the initial stage of gamete interaction.

Characterization of the antigen recognized by a monoclonal antibody MN9: unique transport pathway to the equatorial segment of sperm head during spermiogenesis

MN9, a monoclonal antibody raised against mouse spermatozoa, specifically recognizes the equatorial segment of sperm head in several mammalian species, including humans. Colloidal gold-immuno-electron microscopy of mouse spermatozoa has shown that the antigen is localized in the space between the outer and inner acrosome membranes and on the acrosome membranes at the equatorial segment. Immunoblotting after electrophoresis of spermatozoa from the cauda epididymidis has identified two immunoreactive bands: 38 kDa and 48 kDa in mouse, and 48 kDa in rat. During spermiogenesis in rat, this antigen is transported to the equatorial segment via a unique pathway, first appearing in some cisternae of the endoplasmic reticulum and in the Golgi apparatus of spermatids at around step 3. The antigen can further be found on the vesicles at the trans-side of the Golgi apparatus, in the matrix of the head cap, and on the head cap membrane in step-4 to step-7 spermatids. The antigen appears to be concentrated at the equatorial segment during late spermiogenesis. Neither the (pro-)acrosomic granule nor the surrounding membrane are required in this pathway. This pathway can be termed the 'Golgi-head cap tract'.

Masking the cryptodeterminant on the 54-kilodalton mouse sperm surface antigen

Previously, we reported that the epitope of a 54-kDa sperm surface sialoglycoprotein on the flagellum is masked by sialic acid residues. The epitope is referred to as a hidden determinant or cryptodeterminant. This paper reports the manner in which the epitope is masked as evaluated qualitatively and quantitatively by means of SDS-PAGE/immunoblots (Western blot) and ELISA. Immunoblotting with four specific monoclonal antibodies to the 54-kDa sialoglycoprotein--T21 (IgM), MC71 (IgG1), MC81 (IgM), and MC91 (IgM)--demonstrated that not only IgM but also IgG antibody MC71 and the Fab fragment MC71 are masked. Quantitative evaluation with ELISA to compare the antibody titration curves of the masked and unmasked antigens on sialidase-treated and untreated sperm, respectively, indicated that sialidase caused the antibody-binding ability of the epitopes to increase to a different level for each antibody. There were 32-256-, 8-16-, 16-, and 2-4-fold increases in binding to T21, MC71, MC81, and MC91 antibodies, respectively. These results suggest that the antigen-masking through the cryptodeterminant does not depend upon the subtype or the molecular mass of the antibody, but upon the biochemical nature of the epitope region that is closely related to the sialic acid. The mechanism and physiological roles of the antigen-masking are discussed.

Extra-Golgi pathway of an acrosomal antigen during spermiogenesis in the rat

A monoclonal antibody (MC41) was produced that specifically recognizes a sperm acrosomal antigen of approximately 165,000 dalton in the rat. Rat testis was examined using a pre-embedding immunoperoxidase technique to reveal the pathway of the MC41 antigen to the acrosome during spermiogenesis. The MC41 immunoreaction appeared in several organelles of spermatids in a stage-specific manner: (1) in the endoplasmic reticulum (ER) throughout spermiogenesis, (2) in the outer acrosomal membrane from steps 9 to 19, (3) as a weak immunoreaction in the vesicular structures in the acrosomal matrix from steps 11 to 17, and (4) as a strong immunoreaction in the acrosomal matrix especially at the terminal step of spermiogenesis (step 19). However, no immunoreaction was observed in the Golgi region throughout spermiogenesis. These results suggest that the pathway of the MC41 antigen leads firstly from the ER to the outer acrosomal membrane and secondly to the acrosomal matrix. This pathway does not involve the Golgi apparatus and is referred to as the "extra-Golgi pathway".

A rat sperm flagellar surface antigen that originates in the testis and is expressed on the flagellar surface during epididymal transit

We identified a rat sperm flagellar surface antigen using an IgG1 monoclonal antibody (MC31) against rat epididymal sperm. Avidin-biotin-peroxidase immunohistochemistry demonstrated that the antigen was first expressed in the cytoplasm of early primary spermatocytes, then gradually became restricted to the principal piece of the sperm flagellum during spermatogenesis. However, when the sperm reached the corpus epididymidis, the antigen was expressed on the surface of both the principal piece and the midpiece of the flagellum. The epithelial cells of the epididymis were not stained with MC31. Immunogold electron microscopy showed that the antigen was present on the surface of the sperm flagellar plasma membrane. Immunoblotting of Triton X-100 extracts of epididymal sperm after one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions demonstrated that MC31 detected a major antigen of 26,000-28,000 daltons (26-28K). Two-dimensional isoelectric focusing and SDS-PAGE indicated that the 26-28K antigen had an isoelectric focusing point (pl) of 5.8-5.3; minor antigens were also detected from 26K (pl 5.8) to 35K (pl 5.0). These results indicate that the antigen recognized by MC31 is an acidic 26-35K protein that originates in the testis, is integrated into the sperm flagellar plasma membrane of the principal piece during spermatogenesis, and then is expressed on the entire flagellar surface during epididymal transit.

Appearance of an intra-acrosomal antigen during the terminal step of spermiogenesis in the rat

In a survey of sperm antigens in the rat, a new intra-acrosomal antigen was found using a monoclonal antibody MC41 raised against rat epididymal spermatozoa. The MC41 was immunoglobulin G1 and recognized spermatozoa from rat, mouse and hamster. Indirect immunofluorescence with MC41 specifically stained the crescent region of the anterior acrosome of the sperm head. Immuno-gold electron microscopy demonstrated that the antigen was localized within the acrosomal matrix. Immunoblot study showed that MC41 recognized a band of approximately 165,000 dalton in the extract of rat sperm from the cauda epididymidis. Immunohistochemistry with MC41 demonstrated that the antigen was first detected in approximately step-2 spermatids, and distributed over the entire cytoplasmic region of spermatids from step 2 to early step 19. The head region became strongly stained in late step-19 spermatids and then in mature spermatozoa. Distinct immunostaining was not found in the developing acrosome of spermatids throughout spermiogenesis. These results suggest that the MC41 antigen is a unique intra-acrosomal antigen which is accumulated into the acrosome during the terminal step of spermiogenesis.

Loss of sperm surface sialic acid induces phagocytosis: an assay with a monoclonal antibody T21, which recognizes a 54K sialoglycoprotein

Using a monoclonal antibody T21, we reported that a mouse sperm maturation-associated antigen sialoglycoprotein of 54000 daltons (54K sialoglycoprotein) was secreted at the distal caput to proximal corpus epididymidis and that the 54K sialoglycoprotein had a hidden determinant (cryptodeterminant), which could be eliminated by sialidase treatment (Toshimori et al. (1988): Histochemistry 90:195-200; (1990a): Biol Reprod 42:151-160; (1990b): Arch Histol Cytol 53:339-349). This study evaluated the mouse sperm susceptibility to phagocytosis by macrophage in vitro. Comparisons were made between sperm from the caput epididymidis (caput sperm) incubated in modified Krebs Ringer's solution (MKR) and caput sperm incubated in MKR containing cauda fluid, and between sialylated (sialidase-untreated) sperm from the corpus and cauda epididymidis (corpus/cauda sperm) and desialylated (sialidase-treated) corpus/cauda sperm. The results showed that macrophages were least actively engaged in phagocytosis for caput sperm incubated in MKR containing cauda fluid, and most active for desialylated corpus/cauda sperm. Incubation of caput sperm in MKR containing cauda fluid revealed that the 54K sialoglycoprotein in cauda fluid could be bound to the flagellar surface of caput sperm. These results together with previous findings strongly suggest that the 54K sialoglycoprotein bound to immature sperm during maturation in the epididymis is implicated in the protection of sperm from phagocytosis with the aid of sialic acid residues.

A monoclonal antibody, MN13, that recognizes specifically a novel substance between the postacrosomal sheath and the overlying plasma membrane in the mammalian sperm head

Monoclonal antibody MN13 raised against mouse spermatozoa specifically recognizes the postacrosomal region of the sperm head in several mammalian species. Colloidal gold-immunoelectron microscopy of demembranated mouse spermatozoa indicated that the antigen is associated with the outer layer of the periodic substructure apparently linking the postacrosomal sheath to the overlying plasma membrane. The antigen recognized by MN13 may contribute to the intimate association of the postacrosomal sheath with the overlying plasma membrane.

Digital artery tortuosity and elasticity: a biomechanical study

The gross structure of the digital artery distal to the proximal interphalangeal joint is significantly different from its proximal portion. Previous research in this laboratory has revealed that over half of all fingers exhibit marked tortuosity of this artery in juxtaposition to the distal interphalangeal joint. Any structure with a large amount of bending will have the properties of a spring. An understanding of these properties may help in creating tension-free anastomoses during finger tip replantation. The elastic strength and energy storage capacities of the distal digital artery were measured in 26 cadaver arteries.

Artery anatomy and tortuosity in the distal finger

The arterial architecture in the finger distal to the proximal interphalangeal joint was studied in sixty-seven cadaver fingers with the aid of an operating microscope. The course, frequency, location, and diameter of the dorsal nail fold artery and its anastomosis was recorded. Similar measurements were performed for the palmar anastomosis. The frequency of arterial tortuosity in the digital artery was compiled and a classification of its morphology devised. The characteristic of arterial tortuosity provides a degree of protection to these essential structures. Failure to recognize this facet of arterial anatomy may be one more factor contributing to our inability to successfully revascularize the distal finger in certain patients.

The distal venous anatomy of the finger

An exhaustive anatomic dissection of all of the veins of the finger distal to the proximal interphalangeal joint was done. More than 3200 segments of veins were individually dissected out, measured, and recorded. From this survey new schematic diagrams have been drawn emphasizing the pertinent venous anatomy at the proximal, distal interphalangeal joints and eponychial levels. Suggestions are made for regions that are apt to have the largest vessels available for anastomosis.

Epithelial cells with vacuoles containing 54,000 dalton sialoglycoprotein in the mouse epididymal duct

Epididymal ligation in the mouse induced unusual cells, called peculiar pale epithelial cells (hereafter, pale cells), specifically in the epithelium of the corpus epididymidis (ABE et al., 1982a, b). These pale cells had vacuoles with long microvilli on their inner surface. In this study, we found that the vacuoles of the pale cells occurred in normal mice and contained epididymal specific glycoprotein, sialoglycoprotein of 54,000 dalton (SGP54). This was elucidated by indirect immunofluorescence and avidin biotin complex techniques using monoclonal antibody T21 which specifically recognizes SGP54. These immunoreactive pale cells occurred in the distal caput and proximal corpus of the epididymidis. The relationship between the pale cell and SGP54 is discussed.

Immunohistochemical localization of 54,000 dalton sialoglycoprotein in the epididymal duct of the germ cell-free W/Wv mouse

A monoclonal antibody T21 specifically recognizes the mouse epididymal sialoglycoprotein of 54,000 dalton (SGP54). The localization of SGP54 was studied in the epididymal duct of germ cell-free WBB6F1W/Wv mutant mice (W/Wv mice) by avidin biotin complex (ABC) immunohistochemistry using T21. None of the testis cells showed immunoreaction. No spermatozoa were present in the epididymal duct lumen. The duct luminal fluid was stained weakly in the proximal corpus epididymidis, and strongly in the cauda epididymidis. Degenerated cells appeared in the duct lumen. The degenerated cells located at the corpus epididymidis showed strong immunostaining in the cytoplasmic region, while the degenerated cells located at the cauda epididymidis showed weak immunostaining. Immunoreaction was also detected between and on microvilli along the epididymis, the intensity being very strong at the distal caput and proximal corpus epididymidis. Invaginations and coated vesicles at the luminal surface of the principal cells were frequently immunostained at the corpus epididymidis. Giant inclusions frequently occurred in the principal cells of the distal caput and corpus epididymidis, with these being very intensely immunostained. These inclusions are ultrastructurally confirmed to be giant multivesicular bodies reported by ABE et al. (1984) in the mouse with the efferent duct cutting. These results suggest that the majority of excess SGP54 are absorbed by the principal cells at the distal caput to corpus epididymidis and catalyzed in the giant multivesicular bodies.

Chicken atrial natriuretic peptide (chANP) and its secretion

An immunohistochemical study using antiserum raised against synthetic chicken natriuretic polypeptide was used to investigate the distribution of this peptide in the chicken heart. Immunoreactive cells, both in the atrial and ventricular walls, were identified by electron microscopy, and electron-dense granules in the atrial and ventricular cardiocytes were revealed to be storage sites of the peptide. The electron-dense material, thought to be the peptide, was found in the sarcoplasmic reticulum, and it is suggested that a secretory pathway of the peptide through the latter to extracellular space, may be present, in addition to an exocytotic one.

Cryptodeterminant of a sperm maturation antigen on the mouse flagellar surface

The determinant of a mouse sperm maturation antigen was examined morphologically and biochemically with monoclonal antibody T21 as a probe. The plasma membrane components of cauda epididymal spermatozoa were extracted with nonionic detergent Nonidet P-40 and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions and by immunoblotting. Wheat germ agglutinin-lectin staining and immunoblotting indicated that the antigen recognized by T21 is a sialoglycoprotein of about 54,000 daltons (54 kDa). The antigenic determinant was more distinctly exposed after treatment with neuraminidase, as evaluated by immunohistochemistry, immunocytochemistry, and immunoblotting. The cryptic nature of the determinant was further confirmed by immunostaining nitrocellulose strips, subsequently digesting the strips with neuraminidase, and then reimmunostaining them. Results obtained by periodate oxidation treatment suggested that the epitope is a carbohydrate. Immunoperoxidase electron microscopy confirmed that the antigen is distributed on the flagellar plasma membrane of the sperm. This was demonstrated clearly when sperm were desialylated with neuraminidase. These results indicate that the 54 kDa sialoglycoprotein sperm maturation antigen has a cryptodeterminant which can be masked by a sialic acid residue, that is recognized by monoclonal antibody T21.

Atrial-specific granules in the hearts of normal and water-deprived rats

The morphology of atrial-specific granules, which contain atrial natriuretic polypeptide (ANP), was studied in the cardiac tissue of untreated controls and water-deprived rats by means of conventional and immunoelectron microscopy. Immature secretory vesicles or granules appeared to become buded off from the Golgi cisternae and then fused to form specific A-granules. An electron-dense plate with a fuzzy coat was frequently found on the limiting membrane at the end of such fusion. Pale specific B-granules, which were less electron-dense, larger, and more granular than A-granules, were found in small numbers in the left atrial cardiocytes, but rarely in the right ones. Very pale granules with a less granular matrix, considered to be B-type granules which had lost their electron-density, and which had less immunoreactivity for ANP, were numerous in the cardiac tissue after water deprivation. This morphological change, which is interpreted as an indication of granule degradation, was in agreement with the noted increase of natriuretic activity in the atrial tissue of water-deprived specimens.

Immunohistochemical identification of Purkinje fibers and transitional cells in a terminal portion of the impulse-conducting system of porcine heart

The ultrastructure of porcine ventricular tissue was studied by electron microscopy and immunocytochemical techniques. Electron-dense specific granules were found in both Purkinje fibers and transitional cells in the ventricular walls, and were positively stained by the immunogold staining method using an antiserum against atrial natriuretic polypeptide (ANP). This suggests that both the Purkinje fibers and transitional cells display the same specific granules as atrial cardiocytes containing ANP. These results demonstrate that Purkinje fibers and two types of transitional cells, in addition to the ordinary ventricular cardiocytes, can be identified in porcine ventricular wall tissue.

Masking of sperm maturation antigen by sialic acid in the epididymis of the mouse. An immunohistochemical study

Sperm antigen expression during epididymal transit was examined in 4- to 16-week-old intact and castrated ICR mice, using the avidin-biotin complex (ABC) immunohistochemical method with monoclonal antibody T21 against a flagellar surface antigen. On untreated sections, the antigen was first expressed weakly on sperm in the proximal part of the corpus epididymis, and intraluminal components were stained in 4-week-old mice. Epididymal epithelial cells and their stereocilia, and cells in other reproductive organs were not stained. In contrast, on sections treated with neuraminidase, (1) the initial site of antigen appearance is a more proximal position in treated than in untreated sections, (2) stereocilia stained strongly, (3) the staining intensity of sperm and intraluminal components increased, and (4) some clear cells in the epithelium from the distal position of the caput to the corpus epididymis were stained. These results indicate that the antigen is produced by clear cells of the epididymal epithelium, that the antigenic determinant is masked initially by sialic acid residues, and that expression of the antigenic determinant on the sperm surface during epididymal maturation apparently involves desialylation.

The distribution of atrial natriuretic polypeptide (ANP)-containing cells in the adult rat heart

The present study was performed to clarify the distribution of ANP-containing cells in the adult rat heart by immunostaining for ANP using antiserum against alpha-human ANP. ANP-immunoreactive cells were generally present in the atrial walls except for the sinoatrial node. In the ventricular walls, they were distributed in the impulse conducting system, particularly the left bundle branch, Purkinje fibers on the left side of the interventricular septum, and those in the false tendons in the left ventricle, while they were sporadically seen in the atrioventricular node and bundle of His. The immunoreactive cells contained specific granules that were positive for ANP. These findings demonstrate that ANP-containing cells are present in the atrial and ventricular walls.

Distribution of atrial natriuretic polypeptide (ANP)-containing cells in the rat heart and pulmonary vein. Immunohistochemical study and radioimmunoassay

The distribution of atrial natriuretic polypeptide (ANP) was immunohistochemically surveyed in the rat heart and lung using an antiserum raised against alpha-human ANP. The ANP-immunoreactive cells were seen to be distributed in the atrial walls and proximal portions of the pulmonary vein and venae cavae, but were absent from the aorta, pulmonary arteries, trachea, bronchus, and alveolar cells. The immunoreactive cells were present in a narrow region just beneath the endothelium of the pulmonary vein and vena cavae, and, ultrastructurally and immunocytochemically, were seen to be striated muscle cells with ANP-containing specific granules similar to those seen in atrial cardiocytes. A radioimmunoassay for ANP revealed a content of 604 +/- 51 pg/mg wet weight in the pulmonary vein, and 3343 +/- 1620 pg/mg wet weight in the venae cavae. In addition to the atrial wall, the proximal portion of both the pulmonary vein and venae cavae are suggested to be constituents of an ANP-producing organ.

Filipin-sterol complexes in golden hamster sperm membranes with special reference to epididymal maturation

The distribution of membrane filipin-sterol complexes (FSCs) was qualitatively surveyed on freeze-fracture replicas of spermatozoa from the male reproductive tract and ejaculates of golden hamster. In the head, the acrosomal plasma membrane showed the strongest filipin labeling on the principal segment, but it was absent in the "quilt-like pattern" areas. These latter were observed in both caput and corpus epididymal spermatozoa, but were absent in mature spermatozoa. The postacrosomal plasma membrane had few FSCs and both the outer and inner acrosomal membranes were always negative to filipin. The nuclear membrane of the principal segment was constantly filipin-positive. The nuclear membrane of the postacrosomal region had more FSCs than that of the principal segment, particularly in mature spermatozoa. Many linear, "rod-like FSCs" were observed on the postacrosomal nuclear membrane of mature spermatozoa, especially in the uterine spermatozoan samples. In the neck, the plasma membrane had only a few FSCs. The redundant nuclear membrane was slightly filipin-positive, while the membrane scroll of mature spermatozoa was heavily labeled. In the tail, the plasma membrane of both the middle and principal piece was moderately labeled.

Immunohistochemistry and immunocytochemistry of atrial natriuretic polypeptide in porcine heart

Specific granules in porcine hearts were observed in atrial cardiocytes, Purkinje fibers, and transitional cells of the ventricle. These granule-containing cells were immunohistochemically stained by applying the avidin-biotin-peroxidase complex method using an antiserum against alpha-human atrial natriuretic polypeptide (ANP). Immunoelectron microscopy of sections stained using the immunogold method indicated that these specific granules are storage sites of ANP. Furthermore, an impulse-conducting system consisting of immunoreactive cells was clearly distinguishable from nonimmunoreactive ventricular cardiocytes. We conclude that specific-granule-containing cells, i.e., ANP-producing cells, are located in both the atrial walls and the ventricular impulse-conducting system. The presence of ANP may be correlated with impulse conduction.

Immunohistochemical study of atrial natriuretic polypeptides in the embryonic, fetal and neonatal rat heart

An immunohistochemical study of atrial natriuretic polypeptides was carried out on embryonic, fetal and neonatal rat hearts, using an antiserum raised against alpha-human atrial natriuretic polypeptide (alpha-hANP). Weakly immunoreactive cells were seen in both atrial and ventricular walls at 11 days post coitum (pc). After this stage, the immunoreactive cells became more intensely stained in both atrial and ventricular walls. The immunoreactivity during the prenatal period was stronger in the superficial cell layer beneath the endocardium, than in the deep cell layer of the atrial wall. The cells in the trabecular meshwork also had an apparent, but weak, immunoreactivity, which showed a greater intensity in the left ventricle than in the right one. It is suggested that these immunoreactive cells in the ventricle may differentiate, in situ, into the cells of the impulse-conducting system during the further development of the heart.

Distribution of intramembranous particles and filipin-sterol complexes in mouse sperm membranes: polyene antibiotic filipin treatment

The distribution of intramembranous particles (IMPs) and membrane filipin-sterol complexes (FSC) was examined ultrastructurally in mouse spermatozoa from the male reproductive tract and ejaculates. IMPs were qualitatively analyzed on freeze-fracture replicas of glutaraldehyde-fixed tissue, while membrane FSC were quantitatively analyzed on replicas of filipin-treated cells. The distribution pattern of IMPs of mouse spermatozoa was fundamentally similar to that of other mammalian spermatozoa. 1) In the head, the plasma membrane had a heterogeneous population density, e.g., few IMPs on the acrosomal region, particularly few on the marginal segment, and somewhat regularly arranged IMPs on the postacrosomal region. The acrosomal membrane had many IMPs in hexagonal arrays. The nuclear membrane had many IMPs on the P-face, few IMPs on the variegated E-face, and an intense population density on the P-face of the basal plate. 2) In the neck, the plasma membrane had many IMPs with square arrangements of small IMPs in some areas on the P-face; the redundant nuclear membrane had a few IMPs on both P- and E-faces. 3) In the tail, the plasma membrane had diagonal rows of IMPs in some areas amongst larger IMPs on the middle piece, while it had "zippers" composed of IMPs running parallel to the axis on the principal piece. The distribution of sperm membrane FSC may be summarized as follows: 1) In the head, the acrosomal plasma membrane, which was heavily labeled with filipin, had much more FSC in the equatorial segment than in the marginal segment throughout the study. The postacrosomal plasma membrane generally had no FSC, but some sperm in ejaculates were slightly positive to filipin. The acrosomal membranes (both outer and inner) had no FSC. The nuclear membrane in the main part of the head had less FSC in vas deferens and ejaculated sperm than in the epididymal sperm. The nuclear membrane on the basal plate had no FSC. 2) In the neck, the plasma membrane had little FSC. The redundant nuclear envelope had scattered FSC with a higher incidence in the epididymal sperm than in those from the vas deferens and ejaculates. The membrane scroll, which was elongated from the extreme caudal end of the redundant nuclear envelope, had abundant FSC in the vas deferens and ejaculated sperm. 3) The tail plasma membrane (both middle and principal piece), which was weakly labeled with filipin, had less FSC in sperm from the vas deferens and ejaculates than in those from the epididymis. The limiting membrane covering the mitochondria had no FSC.

Quantitative analysis of zonulae occludentes between oviductal epithelial cells at diestrous and estrous stages in the mouse: freeze-fracture study

The zonulae occludentes between oviductal epithelial cells were quantitatively analyzed at diestrous and estrous stages in the mouse, using the freeze-fracture technique. Zonulae occludentes were predominantly anastomosing at the diestrous stage, while they were predominantly parallel at the estrous stage. The lowest mean value of junctional strands comprising the zonulae occludentes was 5.3 +/- 1.6. Parallel-type zonulae occludentes had more strands than the anastomosing type. Secretory cells usually had more strands than ciliated cells. The shallowest mean depth occupied by junctional domain was 0.51 +/- 0.20 micron. The depth was usually somewhat greater in anastomosing-type zonulae occludentes than in the parallel type. It was also slightly greater in ciliated cells than in secretory cells. The depth was likely to be greater at diestrous stage than at the estrous stage. However, neither the number of strands nor the depth was significantly different between diestrous and estrous stages in homologous types of zonulae occludentes. On the basis of these results, the zonulae occludentes in oviductal epithelium are considered to be morphologically of a tight type at any time period throughout the estrous cycle. The results of lanthanum tracer experiments suggest that the zonulae occludentes in the oviductal epithelium do not always function as a barrier to the exogenous tracer. These morphological phenomena are discussed in relation to mouse fertilization in vivo.

Cellular interconnections in the young mouse ovary. Freeze-fracture study

Intercellular junctions in the young mouse ovary were examined by electron microscopy utilizing freeze-fracture and thin-sectioning techniques. Projections from the granulosa cells adjacent to the oocyte (GI) traverse the zona pellucida and form small gap junctions on the oocyte surface. On the P-face of these cells, the junctional aggregations are occasionally associated with linear strands of particles. In contrast, large gap junctional areas are frequently observed between the more peripherally located granulosa cells (GE) and are also present in the theca interna (TI) cell layer surrounding the follicles. Three types of tight junctional strands are discernible on the P-face of theca externa cells (TE): angularly zigzag strands consisting of intermittently distributed intramembranous particles on wide ridges, intermediate zigzag strands consisting of more continuously distributed particles, and wavy strands consisting of rather fused particles. Tight junctional strands are also present in the middle of grooves on the E-face of endothelial cells of blood vessels. In the germinal epithelial cell layer, tight junctional strands appear to be discrete and form a less anastomosing network.

An unusual architecture of occluding junctions between surface cells in teleost ovarian follicles (Plecoglossus altivelis)

An unusual architecture of occluding junctions between surface cells in teleost ovarian follicles was observed by electron microscopy, by using the freeze-fracture technique. On the P-face, double strands of intramembraneous particles are observed. A narrow furrow-like gap is recognized between two rows of particles in such double strands. On the E-face, two types of grooves can be distinguished. Type I groove consists of a wide furrow. Type II groove, which appears to be sequent to type I groove, consists of a pair of "sub-grooves" running parallel. Further, a row of particles appears to be located in the bottom of type I groove or between two "sub-grooves" of type II groove. These observations suggest that the double strands on the P-face are registered with the grooves (type I or type II) on the complementary E-face and that a row of particles on the E-face is registered with a furrow-like region between two rows in the double strands on the P-face. In other words, a single unit of the juncture of the present occluding junction is thought to consist of triplicated junctional strands.

Cell junctions in the cyst envelope in the silkworm testis, Bombyx mori Linné

The cell junctions of the cyst envelope in the testes of Bombyx mori were examined by electron miscroscopy utilizing a thin-sectioning technique following conventional fixation, tannic acid fixation and lanthanum tracer study, and also using a freeze-fracture technique. There are three kinds of junctions; septate junctions, gap junctions and tight junctions. Septate junctions are of the pleated type. Gap junctions are characterized by four electron-dense lines and three electron-lucent lines in the reduced intercellular spaces seen by thin-sectioning. They are of the "E" type, having clusters of intramembraneous particles on the E-fracture face. The most striking finding is the frequent presence of tight junctions on the fracture planes, while focally fused outer leaflets of the junctional unit membranes are rarely detected on thin-sectioned preparations. Tight junctions are characterized by branching zigzag ridges on the P-fracture face and complementary grooves on the E-fracture face. It is proposed that tight junctions are new morphological evidence of blood-germ cell barrier in an insect.