Cercozoa comprises both EF-1α-containing and EFL-containing members

Elongation factor 1α (EF-1α) and elongation factor-like protein (EFL) are considered to be functionally equivalent proteins involved in peptide synthesis. Eukaryotes can be fundamentally divided into ‘EF-1α-containing’ and ‘EFL-containing’ types. Recently, EF-1α and EFL genes have been surveyed across the diversity of eukaryotes to explore the origin and evolution of EFL genes. Although the phylum Cercozoa is a diverse group, gene data for either EFL or EF-1α are absent from all cercozoans except chlorarachniophytes which were previously defined as EFL-containing members. Our survey revealed that two members of the cercozoan subphylum Filosa (Thaumatomastix sp. and strain YPF610) are EFL-containing members. Importantly, we identified EF-1α genes from two members of Filosa (Paracercomonas marina and Paulinella chromatophora) and a member of the other subphylum Endomyxa (Filoreta japonica). All cercozoan EFL homologues could not be recovered as a monophyletic group in maximum-likelihood and Bayesian analyses, suggesting that lateral gene transfer was involved in the EFL evolution in this protist assemblage. In contrast, EF-1α analysis successfully recovered a monophyly of three homologues sampled from the two cercozoan subphyla. Based on the results, we postulate that cercozoan EF-1α genes have been vertically inherited, and the current EFL-containing species may have secondarily lost their EF-1α genes.     

Resonance in the human medial gastrocnemius muscle during cyclic ankle bending exercise.

We investigated the behavior of the muscle tendon unit (MTU) of the medial gastrocnemius muscle during cyclic ankle bending exercise at eight different frequencies (ranging from 1.33 to 3.67 Hz). The changes in the length of fascicle in the muscle during the exercises were determined by real-time ultrasound imaging. The coordinates of anatomical references and the ground reaction force were determined from video recording and a force plate, respectively. The length change of the MTU (the distance from the origin to insertion of the muscle) was calculated from changes in the knee and ankle joint angles. It was found that the amplitude ratio and phase difference between the fascicle and MTU lengths were both dependent on the movement frequency. At lower frequencies, the fascicle lengths varied almost in phase with the MTU length, whereas they varied out of phase at the higher frequencies. At intermediate frequency, the amplitude of the fascicle became very small compared with that of the MTU, which is considered resonance. We constructed a mechanical model of the MTU based on a notion of forced oscillation in a mass-spring system. The obtained data were well explained by the model. It was concluded that the behavior of the MTU highly depends on the movement frequency due to the viscoelasticity of the MTU.     

Age-related change in sit-to-stand power in Japanese women aged 50 years or older

Background

This study examined whether the age-related change in power, calculated from the score of a sit-to-stand (STS) test, corresponds to those in knee extension torque and leg lean tissue mass in Japanese women aged 50 years or older.

Findings

Time for a 10-times-repeated STS test and knee extension torque were determined in 556 Japanese women aged 50 to 94 years. STS power was calculated using an equation reported previously. In addition, leg lean tissue mass was estimated using muscle thicknesses determined at thigh and lower leg. STS power, knee extension torque, and lean tissue mass were negatively correlated to age. STS power and knee extension torque, expressed as the percentages of the mean value of the corresponding variable for the subjects aged 50 to 54 years were lower than that of lean tissue mass in the subjects aged 60 years or over, and were similar in those aged under 75 years. However, the relative value of STS power was lower than that of knee extension torque in the subjects aged over 75 years.

Conclusions

In Japanese women aged 50 to 74 years, STS power can be a convenient measure for assessing the age-related decline in knee extension torque, but not for leg lean tissue mass. At over 75 years old, the magnitude of the age-related decline in STS power does not parallel to that in the force generation capability of knee extensor muscles.     

Phylogenetic Analysis of the Spider Mite Sub-Family Tetranychinae (Acari: Tetranychidae) Based on the Mitochondrial COI Gene and the 18S and the 5′ End of the 28S rRNA Genes Indicates That Several Genera Are Polyphyletic

The spider mite sub-family Tetranychinae includes many agricultural pests. The internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA have been used for species identification and phylogenetic reconstruction within the sub-family Tetranychinae, although they have not always been successful. The 18S and 28S rRNA genes should be more suitable for resolving higher levels of phylogeny, such as tribes or genera of Tetranychinae because these genes evolve more slowly and are made up of conserved regions and divergent domains. Therefore, we used both the 18S (1,825–1,901 bp) and 28S (the 5′ end of 646–743 bp) rRNA genes to infer phylogenetic relationships within the sub-family Tetranychinae with a focus on the tribe Tetranychini. Then, we compared the phylogenetic tree of the 18S and 28S genes with that of the mitochondrial COI gene (618 bp). As observed in previous studies, our phylogeny based on the COI gene was not resolved because of the low bootstrap values for most nodes of the tree. On the other hand, our phylogenetic tree of the 18S and 28S genes revealed several well-supported clades within the sub-family Tetranychinae. The 18S and 28S phylogenetic trees suggest that the tribes Bryobiini, Petrobiini and Eurytetranychini are monophyletic and that the tribe Tetranychini is polyphyletic. At the genus level, six genera for which more than two species were sampled appear to be monophyletic, while four genera (Oligonychus, Tetranychus, Schizotetranychus and Eotetranychus) appear to be polyphyletic. The topology presented here does not fully agree with the current morphology-based taxonomy, so that the diagnostic morphological characters of Tetranychinae need to be reconsidered.     

Acid Reflux Directly Causes Sleep Disturbances in Rat with Chronic Esophagitis

Background & Aims

Gastroesophageal reflux disease (GERD) is strongly associated with sleep disturbances. Proton pump inhibitor (PPI) therapy improves subjective but not objective sleep parameters in patients with GERD. This study aimed to investigate the association between GERD and sleep, and the effect of PPI on sleep by using a rat model of chronic acid reflux esophagitis.

Methods

Acid reflux esophagitis was induced by ligating the transitional region between the forestomach and the glandular portion and then wrapping the duodenum near the pylorus. Rats underwent surgery for implantation of electrodes for electroencephalogram and electromyogram recordings, and they were transferred to a soundproof recording chamber. Polygraphic recordings were scored by using 10-s epochs for wake, rapid eye movement sleep, and non-rapid eye movement (NREM) sleep. To examine the role of acid reflux, rats were subcutaneously administered a PPI, omeprazole, at a dose of 20 mg/kg once daily.

Results

Rats with reflux esophagitis presented with several erosions, ulcers, and mucosal thickening with basal hyperplasia and marked inflammatory infiltration. The reflux esophagitis group showed a 34.0% increase in wake (232.2±11.4 min and 173.3±7.4 min in the reflux esophagitis and control groups, respectively; p<0.01) accompanied by a reduction in NREM sleep during light period, an increase in sleep fragmentation, and more frequent stage transitions. The use of omeprazole significantly improved sleep disturbances caused by reflux esophagitis, and this effect was not observed when the PPI was withdrawn.

Conclusions

Acid reflux directly causes sleep disturbances in rats with chronic esophagitis.     

High Sensitivity of Late Gadolinium Enhancement for Predicting Microscopic Myocardial Scarring in Biopsied Specimens in Hypertrophic Cardiomyopathy

Background

Myocardial scarring can be assessed by cardiac magnetic resonance imaging with late gadolinium enhancement and by endomyocardial biopsy. However, accuracy of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens remains unknown in hypertrophic cardiomyopathy. We investigated whether late gadolinium enhancement in the whole heart reflects microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy.

Methods and Results

Twenty-one consecutive patients with hypertrophic cardiomyopathy who were examined both by cardiac magnetic resonance imaging and by endomyocardial biopsy were retrospectively studied. The right interventricular septum was the target site for endomyocardial biopsy in all patients. Late gadolinium enhancement in the ventricular septum had an excellent sensitivity (100%) with a low specificity (40%) for predicting microscopic myocardial scarring in biopsied specimens. The sensitivity of late gadolinium enhancement in the whole heart remained 100% with a specificity of 27% for predicting microscopic myocardial scarring in biopsied specimens. Quantitative assessments of fibrosis revealed that the extent of late gadolinium enhancement in the whole heart was the only independent variable related to the microscopic collagen fraction in biopsied specimens (β  =  0.59, 95% confident interval: 0.15 – 1.0, p  =  0.012).

Conclusions

Although there was a compromise in the specificity, the sensitivity of late gadolinium enhancement was excellent for prediction of microscopic myocardial scarring in hypertrophic cardiomyopathy. Moreover, the severity of late gadolinium enhancement was independently associated with the quantitative collagen fraction in biopsied specimens in hypertrophic cardiomyopathy. These findings indicate that late gadolinium enhancement can reflect both the presence and the extent of microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy.     

Herpes simplex virus type 2 US3 blocks apoptosis induced by sorbitol treatment

Previously, we established HEp2 cell lines which express the US3 protein kinase of herpes simplex virus type 2 upon induction with IPTG. Using these cells, we examined whether expression of US3 is sufficient to protect cells from apoptotic cell death induced by sorbitol. Cells expressing US3 showed significantly reduced nuclear fragmentation in the degree that DNA fragmentation and caspase-3 activation were suppressed. It is known that stressors such as osmotic shock and UV irradiation induce the activation of the JNK (c-Jun N-terminal kinase), which can lead to apoptotic cell death. Expression of US3 resulted in the suppression of sorbitol-induced phosphorylation of JNK and MKK4/SEK1, suggesting that the suppression of apoptotic cell death was due to the attenuation of JNK activity.     

A deviant genetic code in the green alga-derived plastid in the dinoflagellate Lepidodinium chlorophorum

We here report a deviant genetic code, in which AUA is read as methionine (Met) instead of isoleucine (Ile), in the green alga-derived plastid in the dinoflagellate Lepidodinium chlorophorum. Although L. chlorophorum cDNA sequences of 11 plastid-encoded genes were deposited in the GenBank database, the non-canonical usage of AUA in this dinoflagellate plastid has been overlooked prior to this study. We compared 11 plastid-encoded genes of L. chlorophorum with the corresponding genes of 17 green algal plastids. Intriguingly, AUA often occurred in the L. chlorophorum sequences at codon positions that are predominantly occupied by Met amongst the green algal sequences. Coincidentally, the L. chlorophorum sequences utilized few AUA codons at the positions predominantly occupied by Ile amongst the green algal sequences. These observations clearly indicated that both AUA and AUG encode Met, while AUU and AUC encode Ile, in the L. chlorophorum plastid. Despite the rapidly-evolving nature of L. chlorophorum plastid-encoded genes, our statistical tests incorporating the deviant code suggest no significant difference in amino acid composition among the L. chlorophorum plastid and the green algal plastids considered in this study. Finally, the possible evolutionary events required for the reassignment of AUA from Ile to Met in Lepitodinium plastids were discussed.     

Tsukubamonas globosa n. gen., n. sp., a novel excavate flagellate possibly holding a key for the early evolution in "Discoba"

We report the ultrastructure and phylogenetic position of a free-living heterotrophic flagellate, Tsukubamonas globosa n. gen., n. sp. This flagellate was isolated from a pond in the University of Tsukuba, Japan. Under light microscopy, the spherical vegetative cells were naked and highly vacuolated, and always swam with rotating motion. Electron microscopic observations revealed that T. globosa possessed a ventral feeding groove, which is one of the hallmark characteristics of the supergroup Excavata. The position of T. globosa was unresolved in the small subunit ribosomal RNA phylogeny. On the other hand, a multigene phylogeny using α-tubulin, β-tubulin, actin, heat shock protein 90, and translation elongation factor 2 robustly united T. globosa with members of the "Discoba" clade of Excavata, composed of jakobids, euglenozoans, and heteroloboseans, although the precise position of T. globosa in this clade remained unresolved. Our detailed morphological comparisons elucidated that T. globosa possessed a novel set of morphological features, and could not be classified into any taxa in the Discoba clade. Instead we classified T. globosa into Tsukubamonadidae n. fam. under Tsukubamonadida n. ord.