Endurance training increases mitochondrial myoglobin and enhances its interaction with complex IV in rat plantaris muscle.

AIM: Endurance exercise training is known to increase mitochondrial respiration in skeletal muscle. However, the molecular mechanisms behind this are not fully understood. Myoglobin (Mb) is a member of the globin family, which is highly expressed in skeletal and cardiac muscles. We recently found that Mb localizes inside mitochondria in skeletal muscle and interacts with cytochrome c oxidase subunit IV (COXIV), a subunit of mitochondrial complex IV, which regulates respiration by augmenting complex IV activity. In the present study, we investigated the effect of endurance training on Mb-COXIV interaction within mitochondria in rat skeletal muscle. METHODS: Eight-week-old male Wistar rats were subjected to 6-week treadmill running training. Forty-eight hours after the last training session, the plantaris muscle was removed under anesthesia and used for biochemical analysis. RESULTS: The endurance training increased mitochondrial content in the skeletal muscle. It also augmented complex IV-dependent oxygen consumption and complex IV activity in isolated mitochondria from skeletal muscle. Furthermore, endurance training increased Mb expression at the whole muscle level. Importantly, mitochondrial Mb content and Mb-COXIV binding were increased by endurance training. CONCLUSION: These findings suggest that an increase in mitochondrial Mb and the concomitant enhancement of Mb interaction with COXIV may contribute to the endurance training-induced upregulation of mitochondrial respiration by augmenting complex IV activity.

Data on mitochondrial respiratory function in skeletal muscle of adult male mice in response to 3-weeks heat stress.

Chronic heat stress induces mitochondrial adaptation in skeletal muscle. However, the effect of chronic heat stress on the respiratory function per mitochondria in skeletal muscle has not been well studied. Here, the present study reports on the effect of 3-weeks heat stress on muscle mitochondrial respiration using male C57BL/6JJ mice at age 21 weeks. Mice were randomly assigned to either the control group (n = 6) or passive heat group (n = 6). After 3-weeks of heat stress, the right triceps surae was removed and used for biochemical analysis. Protein expression was assessed by immunoblotting. Mitochondrial respiratory function was measured by Oxygraph-2k. The study also shows the impact of the heat stress on daily feeding, body weight, muscle weight, and protein expression of heat shock proteins (heat-response marker).

A multilocus sequence typing method of Staphylococcus aureus DNAs in a sample from human skin.

The skin and mucous membranes are the primary sites of Staphylococcus aureus colonization, particularly those of health care personnel and patients in long-term care centers. We found that S. aureus colonized with a higher abundance ratio on skins which had recovered from pressure injury (PI) than on normal skins in our earlier research on the skin microbiota of bedridden patients. Multilocus sequence typing (MLST) is a useful tool for typing S. aureus isolated from clinical specimens. However, the MLST approach cannot be used in microbiota DNA owing to the contamination from other bacteria species. In this study, we developed a multiplex-nested PCR method to determine S. aureus MLST in samples collected from human skins. The seven pairs of forward and reverse primers were designed in the upstream and downstream regions, which were conserved specifically in S. aureus. The first amplifications of the seven pairs were conducted in a multiplex assay. The samples were diluted and applied to conventional PCR for MLST. We confirmed that the method amplified the seven allele sequences of S. aureus specifically in the presence of untargeted DNAs from human and other skin commensal bacteria. Using this assay, we succeeded in typing sequence types (STs) of S. aureus in the DNA samples derived from the skins healed from PI. Peaks obtained by Sanger sequencing showed that each sample contained one ST, which were mainly categorized into clonal complex 1 (CC1) or CC5. We propose that this culture-free approach may be used in detecting S. aureus in clinical specimens without isolation.

Oral microbiome changes associated with the menstrual cycle in healthy young adult females.

The relationship between the menstrual cycle and the oral microbiome has not been clarified. The purpose of this study was to assess potential changes in the oral microbiome of healthy young adults using 16S rRNA-based sequencing. Eleven females (aged 23-36 years) with stable menstrual cycles and without any oral problems were recruited. Saliva samples were collected before brushing every morning during the menstrual period. Based on basal body temperatures, menstrual cycles were divided into four phases, namely the menstrual, follicular, early luteal, and late luteal phases. Our results showed that the follicular phase had a significantly higher abundance ratio of the Streptococcus genus than the early and late luteal phases, whereas the abundance ratios of the Prevotella 7 and Prevotella 6 genera were significantly lower in the follicular phase than those in the early and late luteal phases and that in the early luteal phase, respectively. Alpha diversity by the Simpson index was significantly lower in the follicular phase than that in the early luteal phase, and beta diversity showed significant differences among the four phases. Using the relative abundance data and copy numbers of the 16S rRNA genes in the samples, the bacterial amounts in the four phases were compared, and we observed that the follicular phase had significantly lower amounts of the Prevotella 7 and Prevotella 6 genera than the menstrual and early luteal phase, respectively. These results indicate reciprocal changes with the Streptococcus genus and Prevotella genera, particularly in the follicular phase. In the present study, we showed that the oral microbiome profiles are affected by the menstrual cycles of healthy young adult females.

Phosphine-Catalyzed Anti-Hydroboration of Internal Alkynes.

Trialkylphosphine organocatalysts have enabled regioselective anti-hydroboration of internal alkynes with pinacolborane reagents to provide ( E)-disubstituted alkenylboronate compounds. The alkenylboronate can be used for derivatizations, such as protodeborylation, Suzuki-Miyaura coupling, conjugate reduction, and Diels-Alder reactions.

Phosphine-Catalyzed anti-Carboboration of Alkynoates with 9-BBN-Based 1,1-Diborylalkanes: Synthesis and Use of Multisubstituted γ-Borylallylboranes.

Trialkylphosphine organocatalysis has enabled the regioselective anti-carboboration of alkynoates with 9-BBN-based 1,1-diborylalkanes to produce secondary allylboranes with ß-alkoxycarbonyl and γ-boryl substituents. The utility of the densely functionalized allylboranes was demonstrated by the highly diastereoselective allylation of N-(trimethylsilyl)aldimines to produce homoallylamines containing tertiary allylborane and acrylate moieties.

Catalytic Synthesis of Saturated Oxygen Heterocycles by Hydrofunctionalization of Unactivated Olefins: Unprotected and Protected Strategies.

A mild, general, and functional group tolerant intramolecular hydroalkoxylation and hydroacyloxylation of unactivated olefins using a Co(salen) complex, an N-fluoropyridinium salt, and a disiloxane reagent is described. This reaction was carried out at room temperature and afforded five- and six-membered oxygen heterocyclic compounds, such as cyclic ethers and lactones. The Co complex was optimized for previously rare medium ring formation by hydrofunctionalization of unactivated olefins. The powerful Co catalyst system also enables the deprotective hydroalkoxylation of O-protected alkenyl alcohol and hydroacyloxylation of alkenyl ester to afford cyclic ethers and lactones directly. The substrate scope and mechanistic proof of deprotection were investigated. The experimental evidence supports the concerted transition state of the bond-forming step involving a cationic Co complex.