Distinct roles of the Src family kinases, SRC-1 and KIN-22, that are negatively regulated by CSK-1 in C. elegans

AbstractTo elucidate the primitive roles of the Src family kinases (SFKs), here we characterized Caenorhabditis elegans orthologues of SFKs (src-1 and kin-22) and their regulator kinase Csk (csk-1). SRC-1 and KIN-22 possess the C-terminal regulatory tyrosines characteristic of SFKs, and their activities are negatively regulated by CSK-1 in a yeast expression system. The src-1 and csk-1 genes are co-expressed in some head neurons, the anchor cell and the tail region, while kin-22 and csk-1 genes are co-expressed in pharyngeal muscles and tail region. Expression of KIN-22 induced morphological defects in the pharynx, whereas expression of SRC-1 did not show any overt phenotype in adult. RNA interference of src-1, but not that of kin-22, caused a developmental arrest in early development. These results suggest that SRC-1 and KIN-22 play distinct roles under the control of CSK-1

Regulation of SNAREs by tomosyn and ROCK: implication in extension and retraction of neurites

Extension of neurites requires the SNARE-dependent fusion of plasmalemmal precursor vesicles with the plasma membrane of growth cones. Here, we show that tomosyn localizes at the palm of growth cones and inhibits the fusion of the vesicles there, thus promoting transport of the vesicles to the plasma membrane of the leading edges of growth cones. Tomosyn localizes because ROCK activated by Rho small G protein phosphorylates syntaxin-1, which increases the affinity of syntaxin-1 for tomosyn and forms a stable complex with tomosyn, resulting in inhibition of the formation of the SNARE complex. In retraction of neurites, tomosyn localizes all over the edges of the neurites and inhibits fusion of the vesicles with the plasma membrane. Thus, tomosyn demarcates the plasma membrane by binding to syntaxin-1 phosphorylated by ROCK, and thereby regulates extension and retraction of neurites

Somatic NLRP3 mosaicism in Muckle-Wells syndrome. A genetic mechanism shared by different phenotypes of cryopyrin-associated periodic syndromes

Familial cold autoinflammatory syndrome, Muckle-Wells syndrome (MWS), and chronic, infantile, neurological, cutaneous and articular (CINCA) syndrome are dominantly inherited autoinflammatory diseases associated to gain-of-function NLRP3 mutations and included in the cryopyrin-associated periodic syndromes (CAPS). A variable degree of somatic NLRP3 mosaicism has been detected in ≈35% of patients with CINCA. However, no data are currently available regarding the relevance of this mechanism in other CAPS phenotypes. OBJECTIVE: To evaluate somatic NLRP3 mosaicism as the disease-causing mechanism in patients with clinical CAPS phenotypes other than CINCA and NLRP3 mutation-negative. METHODS: NLRP3 analyses were performed by Sanger sequencing and by massively parallel sequencing. Apoptosis-associated Speck-like protein containing a CARD (ASC)-dependent nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) activation and transfection-induced THP-1 cell death assays determined the functional consequences of the detected variants. RESULTS: A variable degree (5.5-34.9%) of somatic NLRP3 mosaicism was detected in 12.5% of enrolled patients, all of them with a MWS phenotype. Six different missense variants, three novel (p.D303A, p.K355T and p.L411F), were identified. Bioinformatics and functional analyses confirmed that they were disease-causing, gain-of-function NLRP3 mutations. All patients treated with anti-interleukin1 drugs showed long-lasting positive responses. CONCLUSIONS: We herein show somatic NLRP3 mosaicism underlying MWS, probably representing a shared genetic mechanism in CAPS not restricted to CINCA syndrome. The data here described allowed definitive diagnoses of these patients, which had serious implications for gaining access to anti-interleukin 1 treatments under legal indication and for genetic counselling. The detection of somatic mosaicism is difficult when using conventional methods. Potential candidates should benefit from the use of modern genetic tool

Invasive candidiasis leading to gastric perforation in an immunocompromised patient

Invasive candidiasis remains an important cause of mortality and morbidity in patients with underlying diseases. Here, we report a case of gastric perforation due to Candia glabrata infection in a 74-year-old-male with Paroxysmal nocturnal hemoglobinuria (PNH) who received long-term corticosteroid treatment of hemophagocytic syndrome associated with acute cholecystitis. Total gastrectomy was performed, and he was treated liposomal amphotericin B. The patient was extubated successfully on the 2nd postoperative day, but the patient died of Pneumocystis jirovecii pneumonia (PJP). An autopsy revealed that there was a small amount of the cystic form of Pneumocystic jirovecii, but there was not the presence of Candida spp. Concerning the prophylaxis of invasive candidiasis, there is no strong evidence-based data in clinical practice in immunocompromised patients, such as those receiving long-term immunomodulatory therapy or corticosteroids. Our present case suggests the importance of fungal management and may indicate the need for a new approach to the fungal prophylaxis in such patients. Keywords: Invasive candidiasis, Gastric perforation, Immunocompromised patien

Allometric Relationships and Carbon and Nitrogen Contents for Three Major Tree Species (Quercus crispula, Betula ermanii, and Abies sachalinensis) in Northern Hokkaido, Japan

To evaluate the biomass of conifer-broadleaf mixed forests in northern Hokkaido, Japan, the relationships between tree dry masses (including belowground roots) and diameter at breast height (DBH) and tree height (H) for major three tree species (Quercus crispula Blume, Betula ermanii Cham., and Abies sachalinensis (F. Schmidt) Mast.) were calculated. In addition, carbon and nitrogen contents of each tree organ were measured for an accurate estimation of the carbon and nitrogen stocks in the trees. For all three species, one allometric equation explained the relationship between DBH (or DBH2 × H) and the dry masses of whole tree, aboveground total, trunk, branch, and coarse root. Leaf dry mass of Abies, a coniferous species, was higher than that of the two deciduous species at the same DBH. The allometric equations, except that for coniferous leaf, were comparable to previous studies in Hokkaido. The difference in the stand density is a likely reason for the large difference in the coniferous leaf dry mass between studies. Carbon and nitrogen contents for Abies were higher and lower, respectively, than the other two species for all organs (leaf, branch, trunk, and coarse root). Nearly all the measured carbon contents were less than but close to 0.5, and use of the constant value 0.5 caused 1-7% error in the carbon stock estimate of a tree