Sporogenesis in Physcomitrium patens: Intergenerational collaboration and the development of the spore wall and aperture

Although the evolution of spores was critical to the diversification of plants on land, sporogenesis is incompletely characterized for model plants such as Physcomitrium patens. In this study, the complete process of P. patens sporogenesis is detailed from capsule expansion to mature spore formation, with emphasis on the construction of the complex spore wall and proximal aperture. Both diploid (sporophytic) and haploid (spores) cells contribute to the development and maturation of spores. During capsule expansion, the diploid cells of the capsule, including spore mother cells (SMCs), inner capsule wall layer (spore sac), and columella, contribute a locular fibrillar matrix that contains the machinery and nutrients for spore ontogeny. Nascent spores are enclosed in a second matrix that is surrounded by a thin SMC wall and suspended in the locular material. As they expand and separate, a band of exine is produced external to a thin foundation layer of tripartite lamellae. Dense globules assemble evenly throughout the locule, and these are incorporated progressively onto the spore surface to form the perine external to the exine. On the distal spore surface, the intine forms internally, while the spiny perine ornamentation is assembled. The exine is at least partially extrasporal in origin, while the perine is derived exclusively from outside the spore. Across the proximal surface of the polar spores, an aperture begins formation at the onset of spore development and consists of an expanded intine, an annulus, and a central pad with radiating fibers. This complex aperture is elastic and enables the proximal spore surface to cycle between being compressed (concave) and expanded (rounded). In addition to providing a site for water intake and germination, the elastic aperture is likely involved in desiccation tolerance. Based on the current phylogenies, the ancestral plant spore contained an aperture, exine, intine, and perine. The reductive evolution of liverwort and hornwort spores entailed the loss of perine in both groups and the aperture in liverworts. This research serves as the foundation for comparisons with other plant groups and for future studies of the developmental genetics and evolution of spores across plants

Molecular Cloning of Plasmodium vivax Calcium-Dependent Protein Kinase 4

A family of calcium-dependent protein kinases (CDPKs) is a unique enzyme which plays crucial roles in intracellular calcium signaling in plants, algae, and protozoa. CDPKs of malaria parasites are known to be key regulators for stage-specific cellular responses to calcium, a widespread secondary messenger that controls the progression of the parasite. In our study, we identified a gene encoding Plasmodium vivax CDPK4 (PvCDPK4) and characterized its molecular property and cellular localization. PvCDPK4 was a typical CDPK which had well-conserved N-terminal kinase domain and C-terminal calmodulin-like structure with 4 EF hand motifs for calcium-binding. The recombinant protein of EF hand domain of PvCDPK4 was expressed in E. coli and a 34 kDa product was obtained. Immunofluorescence assay by confocal laser microscopy revealed that the protein was expressed at the mature schizont of P. vivax. The expression of PvCDPK4-EF in schizont suggests that it may participate in the proliferation or egress process in the life cycle of this parasite

High-dose Chemotherapy and Autologous Stem Cell Rescue in Patients with High-risk Stage 3 Neuroblastoma: 10-Year Experience at a Single Center

High-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) was applied to improve the prognosis of patients with high-risk stage 3 neuroblastoma. From January 1997 to December 2006, 28 patients were newly diagnosed as stage 3 neuroblastoma. Nine of 11 patients with N-myc amplification and 5 of 17 patients without N-myc amplification (poor response in 2 patients, persistent residual tumor in 2 and relapse in 1) underwent single or tandem HDCT/ASCR. Patients without high-risk features received conventional treatment modalities only. While 8 of 9 patients underwent single HDCT/ASCR and the remaining one patient underwent tandem HDCT/ASCR during the early study period, all 5 patients underwent tandem HDCT/ASCR during the late period. Toxicities associated with HDCT/ASCR were tolerable and there was no treatment-related mortality. While the tumor relapsed in two of eight patients in single HDCT/ASCR group, all six patients in tandem HDCT/ASCR group remained relapse free. The 5-yr event-free survival (EFS) from diagnosis, in patients with N-myc amplification, was 71.6±14.0%. In addition, 12 of 14 patients who underwent HDCT/ASCR remained event free resulting in an 85.1±9.7% 5-yr EFS after the first HDCT/ASCR. The present study demonstrates that HDCT/ASCR may improve the survival of patients with high-risk stage 3 neuroblastoma

Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)

PurposePrevious studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort.MethodsThe levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia.ResultsThe median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ≥75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend=0.0004).ConclusionThe results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants

Kinetic and structural studies on rabbit liver arylsulfatase A

Arylsulfatase A is an acid hydrolase of lysosomal origin which catalyzes the hydrolysis of a variety of aryl and alkyl sulfate esters. An improved procedure for isolation of arylsulfatase A from rabbit liver is presented. The general characteristics of rabbit liver arylsulfatase A (RLASA) are also described. The inhibition constants of various inorganic anions and transition metal oxyanions for RLASA have been determined at different pH values. The pH dependence of the K\sb{\rm i} values indicates that the inhibitors bind to the enzyme as dianions. The order of inhibition at pH 5.0 was sulfite $\u3e$ vanadate $\u3e$ phosphate $\u3e$ tungstate $\simeq$ molybdate $\u3e$ sulfate $\u3e$ chromate. The potent inhibition by sulfite and by transition metal oxyanions is discussed from the viewpoint that these anions are possible transition state analogs. Phenol has little effect on the inhibition by metal oxyanions, suggesting a poor recognition of the phenyl portion of the substrate by the enzyme. It is concluded that the metal ions, aluminum and beryllium, form fluoride complexes that are responsible for the strong inhibition of RLASA. The probable inhibitory species are suggested. Based on the chemical modification studies, it is concluded that lysine and arginine are not essential for the activity of RLASA. RLASA monomer (composed of two equivalent polypeptide chains) does not contain free sulfhydryl groups but contains ten disulfide bonds. Of those, two are shown to be intersubunit disulfides. They are exposed and can be selectively sulfitolysed. The resulting sulfonated enzyme had little enzymatic activity. The generation of activity was accomplished by treatment with DTT and then autoxidation by air. The destruction of an essential histidyl residue may be responsible for an irreversible inactivation that resulted upon irradiation in the presence of vanadate. Native RLASA is shown to be particularly resistant towards proteolysis. The proteinase digestion patterns indicate that RLASA consists of two regions: a large, proteinase-resistant region constituting the N-terminal portion of the polypeptide and a proteinase-vulnerable C-terminal region. Direct sequencing of native RLASA indicated that the N-terminal end of RLASA is not blocked. Over one-third of the protein sequence was determined from peptides obtained by Lys-C and papain digestions as well as by CNBr cleavage. A putative N-glycosylation site was identified. Extensive sequence identity is observed with human ASA sequence. It is proposed that the putative subunit contact region of the RLASA monomer, which consists of two identical subunits, may involve a leucine zipper motif. The activity of the turnover-modified, inactive RLASA is partially regained upon treatment with DTT. It is suggested that the turnover modification of RLASA may involve the cleavage of the intersubunit disulfides by the SO\sb3-like leaving group produced during catalysis