The FASTK family proteins fine-tune mitochondrial RNA processing.

Transcription of the human mitochondrial genome and correct processing of the two long polycistronic transcripts are crucial for oxidative phosphorylation. According to the tRNA punctuation model, nucleolytic processing of these large precursor transcripts occurs mainly through the excision of the tRNAs that flank most rRNAs and mRNAs. However, some mRNAs are not punctuated by tRNAs, and it remains largely unknown how these non-canonical junctions are resolved. The FASTK family proteins are emerging as key players in non-canonical RNA processing. Here, we have generated human cell lines carrying single or combined knockouts of several FASTK family members to investigate their roles in non-canonical RNA processing. The most striking phenotypes were obtained with loss of FASTKD4 and FASTKD5 and with their combined double knockout. Comprehensive mitochondrial transcriptome analyses of these cell lines revealed a defect in processing at several canonical and non-canonical RNA junctions, accompanied by an increase in specific antisense transcripts. Loss of FASTKD5 led to the most severe phenotype with marked defects in mitochondrial translation of key components of the electron transport chain complexes and in oxidative phosphorylation. We reveal that the FASTK protein family members are crucial regulators of non-canonical junction and non-coding mitochondrial RNA processing.

Shortening of Interpupillary Distance after Instillation of Topical Prostaglandin Analog Eye Drops.

PURPOSE: To investigate changes in the interpupillary distance (IPD) after continual instillation of topical prostaglandin analogs (PGAs) in glaucoma patients as an objective indicator of prostaglandin-associated periorbitopathy (PAP). DESIGN: Retrospective, comparative case series. METHODS: A total of 152 institutional patients with glaucoma were enrolled in this study. Inclusion criteria were visual acuities exceeding 10/20 bilaterally and no intraocular surgery during observation. Intervention/observation procedures: First-time bilateral instillation of bimatoprost, travoprost, latanoprost, or tafluprost and IPDs measured by automatic refractometry. IPDs, intraocular pressures (IOPs), and refractive errors were measured before and after continual drug administration (treatment, 2-24 months). MAIN OUTCOME MEASUREMENTS: Post-treatment changes in IPDs. A total of 61 untreated patients served as controls. RESULTS: The IPDs shortened significantly (P < 0.001) after treatment (-0.80 ± 2.1 mm); the IPDs of control subjects remained unchanged (0.05 ± 0.96 mm; P = 0.69). The IPD change after bimatoprost instillation (-2.20 ± 0.97 mm) was significantly (P < 0.001) greater than with other PGAs (-0.65 ± 2.09 mm). The IOPs decreased significantly (P < 0.001) (-3.7 ± 4.3 mm Hg); the refractive errors did not change significantly (P < 0.099) (-0.07 ± 0.69 diopter) post-treatment. The percentages of subjects with 2-mm or greater decreases in IPD after bimatoprost, travoprost, latanoprost, or tafluprost were 85.7%, 20.0%, 18.2%, and 17.2%, respectively, and with 3-mm or greater decreases in IPD 35.7%, 12.0%, 14.5%, and 12.1%, respectively. The specificities were 93.4% and 100% in the control group, respectively, with IPD threshold changes of 2 and 3 mm or more, respectively. CONCLUSIONS: The IPD decreased significantly after topical PGAs within 24 months. The effect was significantly greater with bimatoprost than with other PGAs. The noninvasive, immediate automatic refractometry measurement may be an objective numerical indicator of PAP.

Changes in ruminal and reticular pH and bacterial communities in Holstein cattle fed a high-grain diet.

BACKGROUND: Subacute ruminal acidosis (SARA) is characterized by a ruminal pH depression, and microbiota can also be affected by a higher acidity and/or dietary changes. Previous studies have revealed similar patterns in pH reduction in the rumen and reticulum, whereas changes in reticular pH and bacterial community following a high-grain diet are not fully understood. The aim of this study was to investigate the changes in reticular pH and bacterial community structure following a high-grain diet simultaneously with those in the rumen. RESULTS: SARA was diagnosed when ruminal and reticular pH remained under 5.6 for 350 ± 14 and 312 ± 24 min/d, respectively, on the last day of the CON period. During the CON period, lower proportion of acetic acid and higher proportion of butyric acid were observed compared with the HAY period. The proportions of acetic acid and propionic acid were lower and higher, respectively, in the rumen compared with the reticulum. From 454 pyrosequencing analysis, the relative abundance of several genera differed significantly between the two periods and the two locations. During the HAY period, higher relative abundances of Prevotella, Eubacterium, Oscillibacter, and Succiniclasticum and lower relative abundances of Ruminococcus, Clostridium, and Olsenella were identified compared with the CON period. Furthermore, the relative abundance of Eubacterium was lower in the rumen compared with the reticulum. Bacterial diversity indices were significantly different between the HAY and CON periods, being higher in the HAY period. The quantitative real-time PCR showed that the copy numbers of several cellulolytic bacteria (Fibrobacter succinogenes and Ruminococcus albus) were higher during the HAY period. CONCLUSION: A high-grain diet showed similar impacts on the pH, fermentation, and bacterial community structure in the rumen and reticulum. During the CON period, ruminal and reticular pH decreased following the high-grain challenge, and lower bacterial diversity and changes in the bacterial composition, similarity, and bacterial copy numbers were observed due to a higher acidity and dietary changes compared with the HAY period. These changes may influence the fermentative ability of the rumen and reticulum.

Effects of repeated subacute ruminal acidosis challenges on the adaptation of the rumen bacterial community in Holstein bulls.

We investigated the effect of repeated subacute ruminal acidosis (SARA) challenges on the pH, fermentative function, and bacterial community in the rumen. Four rumen-cannulated Holstein bulls were fed a high-forage diet for 7 d (HF period) followed by a high-grain diet for 7 d (HG period). Four SARA challenges were carried out consecutively (first, second, third, and fourth challenges). The ruminal pH was measured continuously during the experiment, and rumen fluid samples during the first to fourth challenges were collected at 0800, 1400, and 2000 h on the last days of each feeding period for analysis; volatile fatty acid components, NH3-N, and lactic acid concentrations were measured. Bacterial community structure was analyzed at 0800 h during the first and fourth challenges on the last days of each period. The 24-h mean ruminal pH was decreased during the transition from high-forage to high-grain diet and tended to differ between the HF and HG periods. During the HG period, ruminal pH <5.6 was maintained for a longer period in the first and second challenges (350 and 405 min/d, respectively) than in the third and fourth challenges (both 120 min/d). A marked increase in total volatile fatty acid and NH3-N concentrations during the HG period was observed in the later challenges. In addition, lower and higher proportions of acetic and butyric acids, respectively, were observed during the HG period than during the HF period. A total of 37 core bacterial genera were found in all samples; however, the relative abundance of several genera differed significantly between the HF and HG periods (Prevotella, Ruminococcus, Eubacterium, and Oscillibacter) and between the first and fourth challenges (Eubacterium and unclassified Clostridiaceae). During the HG period, lower relative abundances of Prevotella, Eubacterium, and Oscillibacter and higher relative abundance of Ruminococcus were detected compared with during the HF period. The relative abundances of Eubacterium and unclassified Clostridiaceae were lower in the first challenge than in the fourth challenge. Bacterial diversity was greater during the HF period than during the HG period and was greater during the fourth challenge than during the first challenge. Interestingly, diversity indices during the HG period of the fourth challenge were higher than those during the HF period of the first challenge. These results suggested that rumen fermentation in Holstein cattle can adapt to repeated SARA challenges by minimizing the adverse changes in ruminal pH. Moreover, the composition and diversity of the ruminal bacterial community may be affected by ruminal pH and vice versa.

Mechanical properties and biological behavior of carbon nanotube/polycarbosilane composites for implant materials.

Multiwalled carbon nanotube/polycarbosilane (MWCNT/PCS) composites were fabricated by the spark plasma sintering (SPS) method. The MWCNT/PCS composites consisted of MWCNTs and nanosized SiC particles pyrolyzed from PCS and possessing good mechanical properties for bone tissue repair or dental implantation. The MWCNT/PCS composites were implanted in the subcutaneous tissue and femur of rats at 1 and 4 weeks after implantation. Histological investigations showed that there was little inflammatory response in the subcutaneous tissue, and newly formed bone tissue was observed in the femur. These results indicated that the MWCNT/PCS composite had little prophlogistic effect and good osteoconductivity. The study suggested the possibility that the MWCNT/PCS composite could be a candidate bone-substitute and dental-implant material in the future.