Mitochondrial disorders have the highest incidence among congenital metabolic disorders characterized by biochemical respiratory chain complex deficiencies. It occurs at a rate of 1 in 5,000 births, and has phenotypic and genetic heterogeneity. Mutations in about 1,500 nuclear encoded mitochondrial proteins may cause mitochondrial dysfunction of energy production and mitochondrial disorders. More than 250 genes that cause mitochondrial disorders have been reported to date. However exact genetic diagnosis for patients still remained largely unknown. To reveal this heterogeneity, we performed comprehensive genomic analyses for 142 patients with childhood-onset mitochondrial respiratory chain complex deficiencies. The approach includes whole mtDNA and exome analyses using high-throughput sequencing, and chromosomal aberration analyses using high-density oligonucleotide arrays. We identified 37 novel mutations in known mitochondrial disease genes and 3 mitochondria-related genes (MRPS23, QRSL1, and PNPLA4) as novel causative genes. We also identified 2 genes known to cause monogenic diseases (MECP2 and TNNI3) and 3 chromosomal aberrations (6q24.3-q25.1, 17p12, and 22q11.21) as causes in this cohort. Our approaches enhance the ability to identify pathogenic gene mutations in patients with biochemically defined mitochondrial respiratory chain complex deficiencies in clinical settings. They also underscore clinical and genetic heterogeneity and will improve patient care of this complex disorder.

The complete sequence of the mitochondrial DNA (mtDNA) of the true slime mold Physarun polycephalum has been determined. The mtDNA is a circular 62,862-bp molecule with an A+T content of 74.1%. A search with the program BLAST X identified the protein-coding regions. The mitochondrial genome of P. polycephalum was predicted to contain genes coding for 12 known proteins [for three cytochrome c oxidase subunits, apocytochrome b, two F1Fo-ATPase subunits, five NADH dehydrogenase (nad) subunits, and one ribosomal protein], two rRNA genes, and five tRNA genes. However, the predicted ORFs are not all in the same frame, because mitochondrial RNA in P. polycephalum undergoes RNA editing to produce functional RNAs. The nucleotide sequence of an nad7 cDNA showed that 51 nucleotides were inserted at 46 sites in the mRNA. No guide RNA-like sequences were observed in the mtDNA of P. polycephalum. Comparison with reported Physarum mtDNA sequences suggested that sites of RNA editing vary among strains. In the Physarum mtDNA, 20 ORFs of over 300 nucleotides were found and ORFs 14 19 are transcribed.

Mitochondrial disorders have the highest incidence among congenital metabolic diseases, and are thought to occur at a rate of 1 in 5000 births. About 25% of the diseases diagnosed as mitochondrial disorders in the field of pediatrics have mitochondrial DNA abnormalities, while the rest occur due to defects in genes encoded in the nucleus. The most important function of the mitochondria is biosynthesis of ATP. Mitochondrial disorders are nearly synonymous with mitochondrial respiratory chain disorder, as respiratory chain complexes serve a central role in ATP biosynthesis. By next-generation sequencing of the exome, we analyzed 104 patients with mitochondrial respiratory chain disorders. The results of analysis to date were 18 patients with novel variants in genes previously reported to be disease-causing, and 27 patients with mutations in genes suggested to be associated in some way with mitochondria, and it is likely that they are new disease-causing genes in mitochondrial disorders. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.

2-Methyl-3-hydroxybutyryl-CoA dehydrogenase (2M3HBD) deficiency (HSD10 disease) is a rare inborn error of metabolism, and <30 cases have been reported worldwide. This disorder is typically characterized by progressive neurodegenerative disease from 6 to 18 months of age. Here, we report the first patient with this disorder in Asia, with atypical clinical presentation. A 6-year-old boy, who had been well, presented with severe ketoacidosis following a 5-day history of gastroenteritis. Urinary organic acid analysis showed elevated excretion of 2-methyl-3-hydroxybutyrate and tiglylglycine. He was tentatively diagnosed with β-ketothiolase (T2) deficiency. However, repeated enzyme assays using lymphocytes showed normal T2 activity and no T2 mutation was found. Instead, a hemizygous c.460G>A (p.A154T) mutation was identified in the HSD17B10 gene. This mutation was not found in 258 alleles from Japanese subjects (controls). A normal level of the HSD17B10 protein was found by immunoblot analysis but no 2M3HBD enzyme activity was detected in enzyme assays using the patient's fibroblasts. These data confirmed that this patient was affected with HSD10 disease. He has had no neurological regression until now. His fibroblasts showed punctate and fragmented mitochondrial organization by MitoTracker staining and had relatively low respiratory chain complex IV activity to those of other complexes.

The number of children with disability is increasing gradually in Japan. Previous researches in other countries have reported that parents as caregivers (CGs) of children with disability have mental health problems, but the actual situation has not been examined nationwide in Japan so far. The aim of this study was to evaluate the association between mental health of CGs who had children with disability and characteristics of children, CGs, and household based on the nation-wide survey. This study utilized data from 2010 Comprehensive Survey of the Living Conditions, and defined children with disability aged 6 to 17. Individual data of children and CGs were linked, and 549 pairs of them were extracted. The Japanese version of Kessler 6 (K6) was used to assess mental health status of caregiver, scored 5 and over represented to general psychological distress. Logistic regression was used to evaluate the associations of interest. The almost half (44.4%) of CGs had psychological distress (k6 score; 5 +) in nationwide, and 8.9% of CGs might have serious mental illness (K6 score; 13+). After adjusting covariates of child, CG, and household factors, CG having a current symptom (OR, 95% CI: 3.26, 1.97–5.39), CG's activity restriction (OR, 95% CI: 2.95, 1.38–6.32), low social support (OR, 95%CI: 9.31, 1.85–46.8), three generation family (OR, 95% CI: 0.49, 0.26–0.92), and lower 25% tile group of monthly household expenditure (OR, 95% CI:1.92, 1.05–3.54), were significantly associated with psychological distress of CGs. This study encourages health care providers to pay more attentions toward parent's mental health, especially for in case of having low social support, and lower income family. Further research should examine the detailed information of child's disease and disability, medical service use, and quality and quantity of social support in nationwide to straighten the system for supporting services of both children with disabilities and their CGs.

Two FtsZ paralogues (NbFtsZ1 and NbFtsZ2) were isolated from the unicellular green alga Nannochloris bacillaris Naumann. These sequences encoded proteins of 435 and 439 amino acids with tubulin signature motifs (GGGTG[T/S]G), which are important for GTP binding activity. NbFtsZ1 and NbFtsZ2 had four and three introns, respectively, and two different putative core promoters; a TATA box (TATAAAA) and an initiator element (CCCAGG) were located 40 bp and 80 bp upstream of the coding regions of NbFtsZ1 and NbFtsZ2, respectively. Southern blot hybridization and contour‐clamped homogeneous electric field electrophoresis showed that N. bacillaris contained at least one copy of each gene and that NbFtsZ1 was located on chromosome 5 and NbFtsZ2 on chromosome 3 or 4. Phylogenetically, NbFtsZ1 and NbFtsZ2 belong to the vascular plant protein families FtsZ1 and FtsZ2, respectively. The FtsZ1 proteins do not contain carboxy‐terminal consensus sequences, whereas all FtsZ2 proteins possess the consensus sequence (I/V)PxFL(R/K)(K/R)(K/R). Our study has shown that NbFtsZ2 possesses a similar consensus sequence (VPDFLRRK), whereas NbFtsZ1 does not, further supporting their classification as FtsZ2 and FtsZ1. Escherichia coli ftsZ mutants transformed with cloned NbFtsZ1, and NbFtsZ2 cDNAs were restored for the capacity to divide by binary fission, suggesting that the proteins retained the ability to function in the bacterium. An anti‐NbFtsZ2 antibody specifically recognized a single protein band of approximately 51 kDa on an immunoblot of N. bacillaris cellular proteins. Immunostaining of the algal cells with this antibody produced an intense fluorescent signal as a ring near the middle of the cell, which corresponded to the chloroplast division site.

Aim:To clarify the performance situation of selected quality indicators: falls, pressure ulcers and dehydration, at health care facilities for the elderly in Japan, and what structural characteristics are related to them. Methods:The operational population consisted of 1057 institutionalized users (approximately 10 randomly selected per facility) from a survey answered by the care staff. The facilities were divided into two groups according to their prevalence of negative outcomes (falls, pressure ulcers, dehydration): the best 25% (the very good performers) and the remaining 75% (not so good performers). Logistic regression analysis was carried out to examine the relationship between the structure characteristics of the facilities and their performance regarding each quality indicator. Results:After controlling for sex, years of operation and average age of the users, our results showed a beneficial significant relationship between falls and the total number of nurses per 100 users with an adjusted odds ratio (AOR) of 0.77 (95% CI 0.59-0.98); In contrast, for pressure ulcers, harmful associations between a higher number of registered nurses (AOR 1.23, 95% CI 1.01-1.05) and the availability of 24-h nurse staffing (AOR 4.95, 95% CI 1.19-24.91) were found; regarding dehydration, we did not find any related staffing characteristics. Conclusion:Nursing staff might be considered as a potentially related variable in the quality of care in health care facilities for the elderly. The present study is the first to show a relationship between structural characteristics and quality outcomes in health care facilities for the elderly. Geriatr Gerontol Int 2014; 14: 301-308.

Although mitochondria are inherited uniparentally in nearly all eukaryotes, the mechanism for this is unclear. When zygotes of the isogamous protist Physarum polycephalum were stained with DAPI, the fluorescence of mtDNA in half of the mitochondria decreased simultaneously to give small spots and then disappeared completely ∼1.5 hr after nuclear fusion, while the other mitochondrial nucleoids and all of the mitochondrial sheaths remained unchanged. PCR analysis of single zygote cells confirmed that the loss was limited to mtDNA from one parent. The vacant mitochondrial sheaths were gradually eliminated by 60 hr after mating. Using six mating types, the transmission patterns of mtDNA were examined in all possible crosses. In 39 of 60 crosses, strict uniparental inheritance was confirmed in accordance with a hierarchy of relative sexuality. In the other crosses, however, mtDNA from both parents was transmitted to plasmodia. The ratio of parental mtDNA was estimated to be from 1:1 to 1:10-4. Nevertheless, the matA hierarchy was followed. In these crosses, the mtDNA was incompletely digested, and mtDNA replicated during subsequent plasmodial development. We conclude that the rapid, selective digestion of mtDNA promotes the uniparental inheritance of mitochondria; when this fails, biparental inheritance occurs.