Aminopeptidase N from Escherichia coli is a broad specificity zinc exopeptidase belonging to aminopeptidase clan MA, family M1. The structures of the ligand-free form and the enzymebestatin complex were determined at 1.

The localization of vasa homolog protein in the spermatogenic cells of mice, rats, and guinea pigs was studied by immunofluorescence and electron microscopies with the antibody against mouse vasa homolog (MVH) protein. By immunofluorescence microscopy, four types of granular staining patterns were identified: (1) fine particles observed in diplotene and meiotic cells, (2) small granules associated with a mitochondrial marker and appearing in pachytene spermatocytes after stage V, (3) strands lacking the mitochondrial marker in late spermatocytes, and (4) large irregularly shaped granules in round spermatids. Immunoelectron microscopy defined the ultrastructural profiles of these MVH protein-positive granules: the first type consisted of small dense particles, the second had intermitochondrial cement (IMC), the third type, consisting of strands, had loose aggregates of either material dissociated from IMC or 70-90-nm particles, and the fourth had typical chromatoid bodies (CBs). The results suggest that MVH proteins function in these components of nuage. MVH protein-positive structures other than CBs disappeared during meiosis and CB appeared first in early spermatids. The results suggest that the formation of nuage is discontinued between spermatocytes and spermatids. The formation of nuage in spermatocytes and of CB in spermatids is discussed.

The functions of MAELSTROM protein (MAEL) in spermatogenesis are gradually being identified but the precise distribution of MAEL in spermatogenic cells during spermatogenesis has not yet been mapped. We studied the expression of MAEL in rat testis by immunofluorescence and immunoelectron microscopy (IEM). Immunofluorescence staining showed that MAEL was localized in intermitochondrial cement, irregularly-shaped perinuclear granules and satellite bodies of pachytene spermatocytes, and in chromatoid bodies of spermatids. The SBs appeared exclusively in pachytene spermatocytes at stages IX-X and were stained strongly for MAEL. In step 12-19 spermatids, many granules stained for MAEL but not DDX4. These granules were confirmed to be non-nuage structures, including mitochondria-associated granules, reticulated body, granulated body by IEM. In the neck region of late spermatids and sperm, MAEL-positive small granules were found. MAEL is colocalized with MIWI in nuage and non-nuage. The results suggest that MAEL seems to function in nuage and non-nuage structures and interacts with MIWI.

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BackgroundA common SCN5A polymorphism H558R (c.1673 A > G, rs1805124) improves sodium channel activity in mutated channels and known to be a genetic modifier of Brugada syndrome patients (BrS). We investigated clinical manifestations and underlying mechanisms of H558R in BrS.Methods and resultsWe genotyped H558R in 100 BrS (mean age 45 ± 14 years; 91 men) and 1875 controls (mean age 54 ± 18 years; 1546 men). We compared clinical parameters in BrS with and without H558R (H558R+ vs. H558R- group, N = 9 vs. 91). We also obtained right atrial sections from 30 patients during aortic aneurysm operations and compared SCN5A expression and methylation with or without H558R. H558R was less frequent in BrS than controls (9.0% vs. 19.2%, P = 0.028). The VF occurrence ratio was significantly lower (0% vs. 29.7%, P = 0.03) and spontaneous type 1 ECG was less observed in H558R+ than H558R- group (33.3% vs. 74.7%, P = 0.01). The SCN5A expression level was significantly higher and the methylation rate was significantly lower in sections with H558R (N = 10) than those without (0.98 ± 0.14 vs. 0.83 ± 0.19, P = 0.04; 0.7 ± 0.2% vs. 1.6 ± 0.1%, P = 0.004, respectively). In BrS with heterozygous H558R, the A allele mRNA expression was 1.38 fold higher than G allele expression.ConclusionThe SCN5A polymorphism H558R may be a modifier that protects against VF occurrence in BrS. The H558R decreased the SCN5A promoter methylation and increased the expression level in cardiac tissue. An allelic expression imbalance in BrS with a heterozygous H558R may also contribute to the protective effects in heterozygous mutations.Electronic supplementary materialThe online version of this article (doi: 10.1186/s12929-017-0397-x) contains supplementary material, which is available to authorized users.

IntroductionThe single nucleotide polymorphism (SNP) rs2106261 in the transcription factor gene ZFHX3 (16q22), a major regulator of inflammation, has been reported linking to atrial fibrillation (AF) by genome-wide association studies. Inflammation is known to be a strong predictor of atrial fibrillation recurrence after ablation, so we examined the association of the ZFHX3 SNP rs2106261 to inflammation marker expression and recurrence after AF ablation.MethodsWe genotyped ZFHX3 SNP rs2106261 and compared the minor (T) allele frequency between 362 paroxysmal AF (PAF) patients underwent pulmonary vein isolation (PVI) and 627 non-AF controls. We also analyzed associations between ZFHX3 SNP rs2106261 genotype and recurrence rate after pulmonary vein isolation and the inflammation markers.ResultsThe minor (T) allele frequency of the ZFHX3 SNP rs2106261 was significantly higher in AF patients than non-AF controls (odds ratio 1.52, p = 2.2×10−5). Multivariable analysis revealed that the minor allele (T) decreased AF recurrence rate after pulmonary vein isolation (hazard ratio 0.53, p = 0.04). Further, neutrophil/lymphocyte (N/L) ratio, C-reactive protein (CRP), and interleukin-6 (IL-6) expression levels were lower in PAF patients with the ZFHX3 SNP rs2106261 minor allele (TT+TC) than in CC patients (N/L ratio: CC 2.22 ± 0.08, TT+TC 1.98 ± 0.06, p = 0.018; CRP: CC 0.103 ± 0.009 mg/dl, TT+TC 0.076 ±0.007 mg/dl, p = 0.016; IL-6: CC 60.3 ± 3.0 pg/ml, TT+TC 52.8 ± 2.3 pg/ml, p = 0.04).ConclusionsThe ZFHX3 SNP rs2106261 minor allele is associated with lower AF recurrence rate after pulmonary vein isolation. Low baseline inflammation conferred by this allele may reduce AF recurrence risk.

The localization of DDX25/GRTH and gonadotropin-stimulated RNA helicase was studied in the spermatogenic cells of rat, mouse, and guinea pig by immunofluorescence and immunoelectron microscopy (IEM). Immunofluorescence studies identified four kinds of granular staining: (1) fine particles observed in meiotic cells; (2) small granules associated with a mitochondrial marker, appearing in pachytene spermatocytes after stage V; (3) short strands lacking the mitochondrial marker in late spermatocytes; and, (4) large irregularly shaped granules in round spermatids. IEM identified DDX25 signals in nine compartments: (1) fine dense particles in the meiotic cells; (2) intermitochondrial cement; (3) loose aggregates of 70-90 nm particles; (4) chromatoid bodies; (5) late chromatoid bodies; (6) satellite bodies; (7) granulated bodies; (8) mitochondria-associated granules; and, (9) reticulated bodies. Compartments (1) to (6) were previously classified into nuage while (7) to (9) were classified as nuage components by the present study. The results suggest that DDX25 functions in these nine compartments.

It is important to know the localization of medicinal substance, Rb1, of Ginseng, Panax ginseng, in this plant in order to achieve efficient extraction of Rb1 or to culture producing cells. In this report, we describe the localization of Rb1 in various parts of the plant as determined by immunofluorescence (IF) and immunoelectron microscopies (IEM). Using IF, we show that Rb1 is localized to chloroplasts, peroxisomes and cytoplasm but not to vacuoles of leaf parenchymal cells. In the leaf stem, Rb1 is localized to the vascular bundles as well as vacuoles. In the root, vacuoles of parenchymal cells are stained at various intensities. Using IEM, gold particles showing Rb1 antigenic sites are present in the compartments stained by IF technique. In addition, Rb1 is localized in the sieve elements of the phloem and degrading primary cell wall of xylem, and in the root parenchymal cells Rb1 is associated with electron dense polymorphic materials but not in starch granules. Translocation and storage of Rb1 and effective utilization of leaves are discussed.