Background: Prurigo nodularis (PN) is a characteristic chronic dermatosis of unknown etiology showing severely pruritic nodules mainly on the extremities. Atopic diathesis has been implicated as a contributing factor. Objective: Our purpose was to analyze the role of environmental allergens from living organisms in the pathogenesis of PN, to report hypersensitivity against various environmental allergens and to relate this to atopic history in 31 PN patients. Methods: Positive and negative controls were studied including 52 patients with atopic dermatitis (AD) and 22 healthy controls. RAST, prick tests and scarification patch tests were performed on the patients and specimens from lesions of 8 patients were stained with anti-eosinophil cationic protein (ECP) antibody. Results: The 31 PN patients were divided into two groups, those with a past or present history of AD (PN + AD patients) and those without (PN-only patients). Twenty patients (65%) had PN + AD (median age at onset 19 years) and 11 (35%) had PN only (median age at onset 48 years). Analyses of serum IgE levels, RAST scores, prick test and scarification patch test results revealed that the PN + AD patients showed hypersensitive reactions to the environmental allergens in a pattern almost identical to that noted in AD without PN. In contrast, most of those with PN only did not show any hypersensitivity reactions to the environmental allergens. Histologically, many activated eosinophils, identified by monoclonal antibody to ECP, were observed only in the dermis of the PN + AD patients, in contrast to few eosinophils in the lesion of PN-only patients. Conclusions: These results indicate that there are two forms of PN: an atopic and a non-atopic one. The PN + AD group is closely associated with AD, being accompanied by cutaneous hypersensitivity to various environmental allergens (a pattern similar to that displayed by AD patients) and has a younger age of onset, whereas the PN-only group, which showed a much older age of onset, does not show any such hypersensitive reactions against these allergens.

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The non-Mendelian inheritance of organellar DNA is common in most plants and animals. In the isogamous green alga Chlamydomonas species, progeny inherit chloroplast genes from the maternal parent, as paternal chloroplast genes are selectively eliminated in young zygotes. Mitochondrial genes are inherited from the paternal parent. Analogically, maternal mitochondrial DNA (mtDNA) is thought to be selectively eliminated. Nevertheless, it is unclear when this selective elimination occurs. Here, we examined the behaviors of maternal and paternal mtDNAs by various methods during the period between the beginning of zygote formation and zoospore formation. First, we observed the behavior of the organelle nucleoids of living cells by specifically staining DNA with the fluorochrome SYBR Green I and staining mitochondria with 3,3'-dihexyloxacarbocyanine iodide. We also examined the fate of mtDNA of male and female parental origin by real-time PCR, nested PCR with single zygotes, and fluorescence in situ hybridization analysis. The mtDNA of maternal origin was completely eliminated before the first cell nuclear division, probably just before mtDNA synthesis, during meiosis. Therefore, the progeny inherit the remaining paternal mtDNA. We suggest that the complete elimination of maternal mtDNA during meiosis is the primary cause of paternal mitochondrial inheritance.

Abstract:We developed a novel protocol with superior quantitative analysis results for DNA metabarcoding of Collembola, a major soil microarthropod order. Degenerate PCR primers were designed for conserved regions in the mitochondrial cytochrome c oxidase subunit I (mtCOI) and 16S ribosomal RNA (mt16S) genes based on published collembolan mitogenomes. The best primer pair was selected based on its ability to amplify each gene, irrespective of the species. DNA was extracted from 10 natural communities sampled in a temperate forest (with typically 25-30 collembolan species per 10 soil samples) and 10 mock communities (with seven cultured collembolan species). The two gene regions were then amplified using the selected primers, ligated with adapters for 454 technology, and sequenced. Examination of the natural community samples showed that 32 and 36 operational taxonomic units (defined at a 90% sequence similarity threshold) were recovered from the mtCOI and mt16S data, respectively, which were comparable to the results of the microscopic identification of 25 morphospecies. Further, sequence abundances for each collembolan species from the mtCOI and mt16S data of the mock communities, after normalization by using a species as the internal control, showed good correlation with the number of individuals in the samples (R = 0.91-0.99), although relative species abundances within a mock community sample estimated from sequences were skewed from community composition in terms of the number of individuals or biomass of the species. Thus, this protocol enables the comparison of collembolan communities in a quantitative manner by metabarcoding.Key words: metabarcoding, Collembola, 16S, COX1, quantification. Résumé :Les auteurs ont mis au point un protocole pour le métacodage à barres de l'ADN chez les collemboles, un ordre important parmi les micro-arthropodes du sol. Des amorces PCR dégénérées ont été conçues pour les gènes codant pour la sous-unité I de la cytochrome c oxydase mitochondriale (mtCOI) et pour l'ARN ribosomique 16S mitochondrial (mt16S) sur la base des génomes mitochondriaux déjà séquencés chez les collemboles. La meilleure paire d'amorces a été choisie sur la base de sa capacité à amplifier chaque gène, sans égard à l'espèce.

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Background: The pathogenesis of nummular eczema (NE) is still unknown. It often develops on the lower legs of elderly individuals with xerotic changes during the winter months. Such winter exacerbation is also observed in atopic dermatitis, in which there is a high incidence of cutaneous immune reactivities against environmental aeroallergens. Objective: Because of the total lack of information about skin reactivities in NE patients, we performed immunological as well as functional studies in their uninvolved skin. Method: Prick tests and chamber scarification patch tests for representative aeroallergens were conducted on the flexor surface of the forearm in 26 NE patients, in 21 age-matched elderly persons without NE and in 43 healthy young controls. Results: We found that the elderly subjects, regardless of their background, showed a significantly higher immediate skin reactivity to Candida albicans than the young controls. In contrast, patch testing revealed that, unlike the age-matched elderly subjects who showed a decrease in incidence of positive patch test reations, the NE patients retained delayed contact sensitivity at a level comparable to that of the young healthy controls. They showed a significantly higher percentage of positive patch test reactions to Dermatophagoides farinae allergen (46%) and house dust allergen (35%) than the age-matched controls. Moreover, they also showed a significantly higher percentage of delayed hypersensitive reactions to C. albicans allergen (85%) than the age-matched controls (48%). Noninvasive functional assessment of the stratum corneum (SC) in unaffected skin areas of the lower legs in 8 NE patients demonstrated that, though the water barrier function of the SC was comparable to that of the age-matched controls, they showed a significantly lower hydration state of the SC than the age-matched controls. Conclusion: The xerotic skin of elderly individuals facilitates the development of cracking and fissuring of the skin surface in dry and cold winter. Such damage in the SC is sometimes aggravated by inadvertent scratching due to pruritus, allowing skin permeation of various environmental allergens. They may induce eczematous changes in those with preserved adequate delayed hypersensitivity despite their advanced age.

Wistar Hannover rats, which have recently been introduced into Japan, are expected to be used in reproductive and developmental toxicity studies, yet the accumulation of background data is insufficient. This paper describes our historical data on the reproductive ability of this strain of rat. Three lots of sexually matured females (40 each) were received from CLEA JAPAN, Inc. with males of the same strain (30 or 36 each) and mated. A total of 47 dams were killed on gestation day 20 to examine their fetuses. The remaining 71 pregnant females were allowed to deliver spontaneously and observed for common reproductive parameters. The mating and fertility indices of females were both 99.2%. Overall mean numbers of implants and live fetuses at cesarean sectioning were 12.5 and 11.5, respectively. Fetal resorptions and deaths occurred at an incidence of 8.6%. Morphological examinations of fetuses revealed low incidences of spontaneous malformations (each one case of double aortic arch and absent cervical vertebral arch) and a variety of common variations. The followings are overall means of major reproductive parameters obtained from females with live birth: no. of implants, 12.5; no. of pups delivered, 11.8; viability index of pups at birth, 99.8%; and days of age at sexual maturation (vaginal opening and preputial separation), 30.3 and 42.8, respectively. Our present observations confirmed a minimal deviation among 3 lots of animals in terms of reproductive abilities. These results suggest that this strain of rat can be used in reproductive and developmental toxicity studies, although the sensitivity to toxicants remains to be elucidated.