Transcriptome and metabolome analyses of Streptococcus gordonii DL1 under acidic conditions

OBJECTIVES

Streptococcus gordonii is associated with the formation of biofilms, especially those that comprise dental plaque. Notably, S. gordonii DL1 causes infective endocarditis (IE). Colonization of this bacterium requires a mechanism that can tolerate a drop in environmental pH by producing acid via its own sugar metabolism. The ability to survive acidic environmental conditions might allow the bacterium to establish vegetative colonization even in the endocardium due to inflammation-induced lowering of pH, increasing the risk of IE. At present, the mechanism by which S. gordonii DL1 survives under acidic conditions is not thoroughly elucidated. The present study was thus conducted to elucidate the mechanism(s) by which S. gordonii DL1 survives under acidic conditions.

METHODS

We analyzed dynamic changes in gene transcription and intracellular metabolites in S. gordonii DL1 exposed to acidic conditions, using transcriptome and metabolome analyses.

RESULTS

Transcriptome analysis revealed upregulation of genes involved in heat shock response and glycolysis, and down regulation of genes involved in phosphotransferase systems and biosynthesis of amino acids. The most upregulated genes were a beta-strand repeat protein of unknown function (SGO_RS06325), followed by copper-translocating P-type ATPase (SGO_RS09470) and malic enzyme (SGO_RS01850). The latter two of these contribute to cytoplasmic alkalinization. S. gordonii mutant strains lacking each of these genes showed significantly reduced survival under acidic conditions. Metabolome analysis revealed that cytoplasmic levels of several amino acids were reduced.

CONCLUSIONS

S. gordonii survives the acidic conditions by recovering the acidic cytoplasm using the various activities, which are regulated at the transcriptional level.

Phylloquinone is preferable over menadione as a growth factor for Porphyromonas gingivalis

OBJECTIVES

Porphyromonas gingivalis is the etiological agent of chronic periodontitis. Menadione (vitamin K3) and phylloquinone (vitamin K1) are well-known growth factors for P. gingivalis, while menadione is widely used in growth experiments. Here we attempted to determine the differences in phylloquinone and menadione in P. gingivalis growth experiments, which have not been well studied to date.

METHODS

We investigated the effects of menadione and phylloquinone on the growth of two W83 strains and seven ATCC 33277 strains of P. gingivalis.

RESULTS

The ATCC 33277 strains grew well with phylloquinone at 2.9 μM in a complex medium (nutrient medium) and at 29 μM in two minimal media. In contrast, the W83 strains grew well without menadione or phylloquinone in three different culture media. Menadione at 2.9 μM, the conventionally used concentration for culturing P. gingivalis, supported the growth of most ATCC 33277 strains but inhibited the growth of some W83 and ATCC 33277 strains. Furthermore, menadione at 14.5 μM frequently inhibited cell growth, while phylloquinone at 145 μM promoted cell growth.

CONCLUSIONS

These results indicate that menadione and phylloquinone act as growth factors for ATCC 33277 but that menadione also can inhibit P. gingivalis growth. Thus, we propose that phylloquinone be used instead of menadione in P. gingivalis growth experiments requiring vitamin K.

Intraplaque wiring enables drug-coated balloons to be utilized for percutaneous recanalization of chronically occluded coronary arteries

OBJECTIVES

This study aimed to determine whether drug-coated balloon (DCB) angioplasty following intraplaque wiring and the use of modified balloons is safe and effective in the percutaneous treatment of coronary chronic total occlusions (CTOs).

BACKGROUND

DCB is an alternative therapeutic option without the limitations of permanent vascular implants. However, its efficacy in CTOs has yet to be confirmed. The combination of modified balloons and DCB can be effectively applied when the intraplaque passage of the guidewire is achieved in CTOs.

METHODS

Data from 124 consecutive CTO lesions (105 patients) treated at our hospital between February 2016 and December 2020 were screened for inclusion and retrospectively analyzed. Among the 118 lesions successfully recanalized, intraplaque wiring was achieved in 108, and 85 were treated by the DCB-only approach following cutting/scoring balloon dilatation.

RESULTS

Follow-up data were available for 82 lesions (71 patients). The median occlusion length was 18.5 mm, and the J-CTO score was 1.7 ± 0.9. No in-hospital major adverse cardiac events occurred, including abrupt vessel closure. During the median 29-month follow-up period, target lesion revascularization was performed for 10 lesions. Follow-up coronary angiography (8.7 ± 3.9 months after the index procedure) was performed for 64 lesions, demonstrating late lumen loss of -0.15 mm (interquartile range -0.4 to 0.23 mm), binary restenosis (diameter stenosis ≥50%) in 12 lesions (18.8%), and late lumen enlargement in 37 (57.8%).

CONCLUSION

The DCB-only approach following the use of modified balloons is a promising strategy for coronary CTOs when intraplaque wiring is achieved.

Relationship Between Nonsmoothness in Adversarial Training, Constraints of Attacks, and Flatness in the Input Space

Adversarial training (AT) is a promising method to improve the robustness against adversarial attacks. However, its performance is not still satisfactory in practice compared with standard training. To reveal the cause of the difficulty of AT, we analyze the smoothness of the loss function in AT, which determines the training performance. We reveal that nonsmoothness is caused by the constraint of adversarial attacks and depends on the type of constraint. Specifically, the L∞ constraint can cause nonsmoothness more than the L2 constraint. In addition, we found an interesting property for AT: the flatter loss surface in the input space tends to have the less smooth adversarial loss surface in the parameter space. To confirm that the nonsmoothness causes the poor performance of AT, we theoretically and experimentally show that smooth adversarial loss by EntropySGD (EnSGD) improves the performance of AT.

Regulation of constant cell elongation and Sfm pili synthesis in Escherichia coli via two active forms of FimZ orphan response regulator

Escherichia coli (E. coli) has multiple copies of the chaperone-usher (CU) pili operon in five fimbria groups: CU pili, curli, type IV pili, type III secretion pili, and type IV secretion pili. Commensal E. coli K-12 contains 12 CU pili operons. Among these operons, Sfm is expressed by the sfmACDHF operon. Transcriptome analyses, reporter assays, and chromatin immunoprecipitation PCR analyses reported that FimZ directly binds to and activates the sfmA promoter, transcribing sfmACDHF. In addition, FimZ regularly induces constant cell elongation in E. coli, which is required for F-type ATPase function. The bacterial two-hybrid system showed a specific interaction between FimZ and the α subunit of the cytoplasmic F1 domain of F-type ATPase. Studies performed using mutated FimZs have revealed two active forms, I and II. Active form I is required for constant cell elongation involving amino acid residues K106 and D109. Active form II additionally required D56, a putative phosphorylation site, to activate the sfmA promoter. The chromosomal fimZ was hardly expressed in parent strain but functioned in phoB and phoP double-gene knockout strains. These insights may help to understand bacterial invasion restricted host environments by the sfm γ-type pili.

Calcium ions and vitamin B12 are growth factors for Porphyromonas gingivalis

BACKGROUND

Porphyromonas gingivalis is a causative agent of chronic periodontitis. Standard strains of P. gingivalis, such as W83 and ATCC 33277, proliferate in minimal medium when protein is added as the energy source and hemin and menadione are added as growth factors. Nevertheless, minimal medium containing bovine serum albumin sometimes fails to support growth.

HIGHLIGHTS

The proliferation of two W83 strains and seven ATCC 33277 strains in various minimal media was investigated. Previously, we determined that calcium chloride (CaCl₂) was a growth factor for W83NM, a W83 strain. In this study, we found that vitamin B₁₂ enhanced the proliferation of W83NM in a minimal medium with cultures from the fourth passage but not from the first to the third passage. Therefore, using fourth-passage cultures, we assessed the proliferation of two W83 and seven ATCC 33277 strains in minimal media and the effects of CaCl₂ and vitamin B₁₂. Surprisingly, the nine P. gingivalis strains all differed with respect to their proliferation in minimal media, and protein products used as energy sources showed product-to-product and lot-to-lot heterogeneity. Even though strains or protein products were different, we found CaCl₂-dependent growth in nine strains and vitamin B₁₂-dependent growth in seven strains.

CONCLUSION

These results suggest that calcium ions and vitamin B₁₂ are novel growth factors for P. gingivalis.

Laser vaporization of atherothrombotic burden before drug-coated balloon application in ST-segment elevation myocardial infarction: Two-year outcomes of the laser-DCB trial

OBJECTIVES

This study aimed to examine whether the combination of excimer laser coronary atherectomy (ELCA) and drug-coated balloon (DCB) angioplasty can provide feasible clinical outcome in patients with ST-segment elevation myocardial infarction (STEMI) with 8-month and 2-year scheduled follow-up angiography.

BACKGROUND

Intracoronary thrombus elevates the risk of interventional treatment in patients with STEMI and hampers drug absorption into the vasculature released from DCB.

METHODS

Sixty-two patients with STEMI within 24 h after the onset of symptoms were enrolled in this prospective, single-center, single-arm study.

RESULTS

The laser catheter was successfully crossed distal to the culprit lesion in all cases. No ELCA-related adverse events occurred. Bail-out stenting was required in two patients (3.2%) after adjunctive ballooning; thus, the remaining 60 patients were completed with DCB angioplasty without stenting. Scheduled angiography at 8 months and 2 years was completed in 100% and 85.2%, respectively, and minimal lumen diameters were 3.4 ± 0.5, 3.4 ± 0.6, and 3.4 ± 0.5 mm after the procedure, at 8 months and at 2 years, respectively. Binary restenosis was observed in five patients (8.1%) in whom target lesion revascularization was performed. The duration of dual antiplatelet therapy was 2.3 ± 2.2 months, and neither abrupt vessel closure, reinfarction, cardiac death nor major bleeding was observed.

CONCLUSION

A combination of DCB angioplasty with ELCA is a feasible therapeutic option for STEMI.

Analysis of sagittal thoracolumbar spine and hip joint movements during sit-to-stand using a 2D image analysis freeware

[Purpose] This study aimed to verify the utility of an image analysis freeware in the evaluation of thoracolumbar spine and hip joint movements during sit-to-stand movement and show the importance of separately analyzing the movements of the thoracolumbar spine and the hip joint. [Participants and Methods] We used a two-dimensional image analysis freeware to analyze the kinematics of the thoracolumbar spine and the hip joint during sit-to-stand movements in seven healthy young males. We further examined the usefulness of the freeware by verifying the concordance of its angle measurements with those of a three-dimensional motion analysis device. Moreover, we evaluated joint coordination of the thoracolumbar spine with hip joint movements in pregnant female before and after delivery by measuring the relative phase angle. [Results] The trunk angle and relative phase angle between the thoracolumbar spine and the hip joint obtained using the two different analytical methods were fairly consistent. In the analysis of the pregnant female, the degree of thoracolumbar flexion prior to hip flexion tended to decrease. Similarly, the degree of hip extension tended to decrease during pregnancy. [Conclusion] This study shows that a two-dimensional image analysis freeware could be useful and meaningful in the calculation of thoracolumbar spine and hip joint movements and in the detection of synergistic patterns of these entities during sit-to-stand movement.

Streptococcus gordonii DL1 evades polymorphonuclear leukocyte-mediated killing via resistance to lysozyme

Streptococcus gordonii is an etiological bacterial agent of infective endocarditis. Although the pathogenesis mechanisms are not well understood, the interaction between streptococci and phagocytes is considered important for the development of infective endocarditis. Previous studies show that some S. gordonii strains, including DL1, survive in polymorphonuclear leukocytes (PMNs), whereas other strains such as SK12 are sensitive to PMN-dependent killing. In this study, we assessed the differences between the sensitivity of S. gordonii DL1 and S. gordonii SK12 to PMN-dependent killing. S. gordonii DL1 showed a higher survival when treated with PMNs than SK12. Both S. gordonii DL1 and S. gordonii SK12 showed high resistance to low pH condition. Compared to S. gordonii SK12, S. gordonii DL1 was sensitive to hydrogen peroxide. However, the resistance of S. gordonii DL1 to the tested bactericidal agents, especially lysozyme, was higher than that of SK12. Furthermore, we performed a bactericidal assay by treating a mixture of S. gordonii DL1 and SK12 with PMNs. S. gordonii DL1 did not enhance the survival of S. gordonii SK12 exposed to PMNs. These results indicated that S. gordonii DL1 is resistant to bactericidal agents that degrade bacteria in phagolysosomes. In addition, there was no secretory factor involved in the resistance to bactericidal agents. The findings of this study may help develop treatments for infective endocarditis caused by S. gordonii.

Expression and diversity of the sialic acid-binding adhesin and its homologs associated with oral streptococcal infection

Streptococcus gordonii, one of the early colonizers of oral biofilms, is involved in the development of dental caries, periodontal disease, and infective endocarditis. The Hsa adhesin of S. gordonii DL1 has the ability to bind strongly to the terminal sialic acid groups of host glycoproteins via the binding region, NR2, which is important for the pathogenicity of S. gordonii DL1. Low similarity with the NR2 of Hsa homologs among other streptococcal species has been reported. However, the reports have been limited to certain strains. This study attempted to assess frequency of the expression on the bacterial cell surface and to analyze the diversity of Hsa homologs among different wild strains of oral streptococci. We isolated 186 wild-type strains of oral streptococci from healthy volunteers and analyzed their hemagglutinating activity on human erythrocytes and their Hsa homologs and NR2 homologous regions by dot immunoblotting using anti-Hsa and anti-NR2 antisera, respectively. We found 30 strains reacted with anti-NR2 antiserum (NR2-positive) and determined the sequence of the NR2 regions. Many strains with high hemagglutinating activity were also NR2-positive, suggesting that the NR2 region may be associated with hemagglutinating activity. Among the NR2-positive strains, four different amino acid sequence patterns were observed, demonstrating diversity in the NR2 region. Notably, S. gordonii strains frequently possessed Hsa homologs and NR2-like antigens compared to other streptococci. It is speculated that the possessing frequency of Hsa homologs and the amino acid sequence of NR2 region may vary among streptococcal species. This article is protected by copyright. All rights reserved.

Genetic code expansion enables visualization of Salmonella type three secretion system components and secreted effectors

Type three secretion systems enable bacterial pathogens to inject effectors into the cytosol of eukaryotic hosts to reprogram cellular functions. It is technically challenging to label effectors and the secretion machinery without disrupting their structure/function. Herein, we present a new approach for labeling and visualization of previously intractable targets. Using genetic code expansion, we site-specifically labeled SsaP, the substrate specificity switch, and SifA, a here-to-fore unlabeled secreted effector. SsaP was secreted at later infection times; SsaP labeling demonstrated the stochasticity of injectisome and effector expression. SifA was labeled after secretion into host cells via fluorescent unnatural amino acids or non-fluorescent labels and a subsequent click reaction. We demonstrate the superiority of imaging after genetic code expansion compared to small molecule tags. It provides an alternative for labeling proteins that do not tolerate N- or C-terminal tags or fluorophores and thus is widely applicable to other secreted effectors and small proteins.

Role of Streptococcus intermedius phosphoglucosamine mutase in bacterial growth, cell morphology, and resistance to polymorphonuclear leukocyte killing

OBJECTIVES

Streptococcus intermedius is a member of the anginosus group of streptococci, an oral commensal bacterium found in infected root canals, and the causative agent of deep-seated abscesses. This organism has slow clearance when phagocytosed within neutrophils. Here, we investigated the role of its phosphoglucosamine mutase (GlmM), an enzyme associated with peptidoglycan synthesis, in bacterial growth, cell morphology, and resistance to polymorphonuclear leukocyte killing.

METHODS

The glmM-deletion (ΔglmM) mutant and the plasmid-borne complementation (ΔglmM/glmM) strain of S. intermedius were generated. The wild type, the ΔglmM mutant, and the ΔglmM/glmM strain were phagocytosed with human polymorphonuclear leukocytes (PMNs), and bacterial viability in PMNs was determined by LIVE/DEAD staining. Additionally, bacterial growth and cell morphology were also compared.

RESULTS

The survival rate of the ΔglmM mutant was significant lower than that of the wild type. Although the difference in the survival rate of the ΔglmM/glmM strain compared to that of the wild type or the ΔglmM mutant was not significant, the rate appeared to be restored to the middle level. Compared to the wild type and the ΔglmM/glmM strain, the ΔglmM mutant showed reduced growth potential, a significant increase in the number of bacterial chains, and heterogeneous bacteria.

CONCLUSIONS

GlmM is one of the factors responsible for the stable resistance of S. intermedius to clearance by PMNs.

The SARC-F Score on Admission Predicts Falls during Hospitalization in Older Adults

OBJECTIVES

Community-dwelling older adults with sarcopenia are likely to fall. However, few studies have investigated whether sarcopenia is associated with falls during hospitalization in older adults. The purpose of this study was to determine whether the SARC-F when used as a simple screening tool for sarcopenia at the time of admission, predicts in-hospital falls.

DESIGN

A retrospective, observational study.

SETTING

A 900-bed university hospital.

PARTICIPANTS

A total of 9,927 patients aged 65 years and older were hospitalized at the hospital between April 2019 and March 2020.

MEASUREMENTS

The SARC-F contains five items: strength, assistance in walking, rise from a chair, climb stairs, and falls were evaluated at hospital admission. To investigate the relationship between the SARC-F score and falls, a ROC curve analysis was performed. Multivariate analysis adjusted for fall-related confounding factors such as age, gender, ADL, and disease were performed.

RESULTS

Mean age: 75.9±6.7 years; male: 56.2% were analyzed, and 159 patients (1.6%) fell during hospitalization. SARC-F scores at admission were significantly higher in the fall group than in the control group (3 [1-6] points vs. 0 [¬0-2] point, p<0.001). Statistical association was observed between the SARC-F and in-hospital fall (area under the curve = 0.721 [0.678-0.764], p < 0.001). The cut-off value for the highest sensitivity and specificity of the SARC-F score for in-hospital falls was two (sensitivity = 0.679, specificity = 0.715). Among the subitem of the SARC-F, the hazard ratios for climbing stairs were significantly higher (HR = 1.52 [1.10-2.09], p = 0.011) and for a history of fall was significantly higher (HR = 1.41 [1.02-1.95], p = 0.036). A SARC-F score ≥ 2 had a significantly higher incidence of in-hospital falls compared to a SARC-F score <2 (3.7% vs. 0.7%, p < 0.001). Also, a SARC-F score ≥ 2 had a significantly higher hazard ratio for falls (2.11 [1.37-3.26], p < 0.001).

CONCLUSION

SARC-F can help predict falls among hospitalized older adults.

SARC-F Predicts Mortality Risk of Older Adults during Hospitalization

OBJECTIVES

To determine the association between SARC-F scores and the in-hospital mortality risk among older patients admitted to acute care hospitals.

DESIGN

Single-center retrospective study.

SETTING

A university hospital.

PARTICIPANTS

All consecutive patients aged older than 65 were admitted and discharged from the study hospital between July 2019 and September 2019.

MEASUREMENTS

Relevant patient data included age, sex, body mass index, nutritional status, fat-free mass, disease, activities of daily living (ADL), duration of hospital stay, SARC-F, and occurrence of death within 30 days of hospitalization. The diseases that caused hospitalization and comorbidities (Charlson Comorbidity Index; CCI) were obtained from medical records. The Eastern Cooperative Oncology Group-performance status (PS) was used to determine ADL, and the in-hospital mortality rate within 30 days of hospitalization as the outcome.

RESULTS

We analyzed 2,424 patients. The mean age was 75.9±6.9 and 55.5% were male. Fifty-three in-hospital mortalities occurred among the participants within the first 30 days of hospitalization. Patients who died in-hospital were older, had poorer nutritional status and severer PS scores, and more comorbidities than those who did not. A SARC-F score of ≥4 predicted a higher mortality risk within those 30 days with the following precision: sensitivity 0.792 and specificity 0.805. There were significantly more deaths in Kaplan-Meier curves regarding a score of SARC-F≥4 than a score of SARC-F<4 (p<0.001). Cox proportional hazard analysis was used to identify the clinical indicators most associated with in-hospital mortality. SARC-F≥4 (Hazard Ratio: HR 5.65, p<0.001), CCI scores (HR1.11, p=0.004), and infectious and parasitic diseases (HR3.13, p=0.031) were associated with in-hospital mortality. The SARC-F items with significant in-hospital mortality effects were assistance with walking (HR 2.55, p<0.001) and climbing stairs (HR 2.46, p=0.002).

CONCLUSION

The SARC-F questionnaire is a useful prognostic indicator for older adults because a SARC-F ≥4 score during admission to an acute care hospital predicts in-hospital mortality within 30 days of hospitalization.

A bolus of saline injection leads to increase in coronary flow based on the viscosity reduction effect: the mechanism of saline induced Pd/Pa ratio

Background

In conjunction with fractional flow reserve (FFR), our previous study has shown the accuracy and utility of saline induced Pd/Pa ratio (SPR) for the assessment of myocardial ischemia. However, the potential mechanism how saline injection leads to increase in coronary flow remains speculative.

Purpose

This study aimed to clarify the underlying mechanism of SPR by using swine models.

Methods

The study was conducted in four swine models, and bolus of 25°C saline, 40°C saline, and 25°C dextran was injected at rates of 40mL/5sec through a catheter inserted into the superior mesenteric artery. Its peripheral arterioles were observed and recorded by a digital microscope, and transit time of each fluid and a luminal diameter of arterioles before and after injection were measured.

Results

The result from arterioles diameters of pre- and post-injection (0.049±0.016mm vs. 0.050±0.016mm; P=0.636) indicated that luminal diameters remained unchanged regardless of fluid administration. The transit time of 25°C saline was significantly shorter than 25°C dextran (3.19±0.68sec vs. 6.15±1.19sec; P&lt;0.0001). Although the result showed no significance, the transit time of 40°C saline with lower viscosity was shorten compared to 25°C saline (3.1±0.43sec vs. 3.65±0.46sec; P=0.088).

Conclusions

Compared to 25°C dextran (viscosity of 4.991mPa·s) having the same viscosity as 37°C whole blood, 25°C saline (viscosity of 1.012mPa·s) caused increasing to double the intravascular flow volume without dilating arterioles. The results strongly suggested that the potential mechanism of SPR was viscosity reduction effect. Combined with FFR which is based on vasodilation-mediated hyperemia, these findings may contribute to clarifying the pathophysiology and especially the microcirculation in coronary artery diseases.

Funding Acknowledgement

Type of funding source: None

The developing mechanism of atherosclerotic lesion in coronary side branch on the ventricular free wall differs by the location of lesion

Background

The effective treating method of coronary side branch lesions such as ostial stenosis or thin arteries has not been established. On the other hand, tortuous side branch rarely has stenotic lesions.

Purpose

We focused on coronary side branches on the ventricular free wall, and examined coronary risk factors and bending and stretching motion of branch which can contribute to the development of atherosclerotic lesion.

Methods

In elective and first-time coronary angiograms, we included side branches on the ventricular free wall (&gt;2mm in diameter) and excluded previously treated ones. Study A; we divided arteries into proximal, middle, and distal segment, and examined the presence of tortuosity and stenotic lesions exceeding 50% diameter stenosis (DS) for each segment. A score of 1 was assigned to tortuous segment, and 0 to non-tortuous one. Study B; we included stenotic lesion (&gt;50% DS) in side branch ostium and excluded those extended across main coronary arteries. Relation between lesions and patients' characteristics was examined.

Results

Study A; in 1,828 side branches from 472 patients, middle and distal segments had significantly higher tortuosity score than proximal (0.68, 0.78 vs. 0.34; p&lt;0.0001). On the contrary, proximal segments had more stenotic lesions except ostial stenosis (230 vs. 69, 5; p&lt;0.0001). Study B; in 1,740 side branches from 465 patients, 122 ostial stenotic lesions were found (7.0%). Multivariate logistic regression analysis revealed diabetes mellitus and age as independent contributors to development of ostial stenosis (Table).

Conclusions

Side branch stenosis developed less frequently in middle and distal segments, where stronger ventricular wall motion reinforces bending and stretching motion and tortuosity of arteries. This fact indicates that those characteristics may prevent developing atherosclerosis through increasing shear stress. On the other hand, diabetes mellitus strongly contributes to the development of ostial stenosis. Thus, the developing mechanism of atherosclerotic lesion in side branch on the ventricular free wall differs by the location of lesion.

Funding Acknowledgement

Type of funding source: None

Measurement of the Promoter Activity in Escherichia coli by Using a Luciferase Reporter

The reporter system is widely used technique for measuring promoter activity in bacterial cells. Until now, a number of reporter system have been developed, but the bioluminescent reporter constructed from the bacterial luciferase genes is one of the useful systems for measuring in vivo dynamics of gene expression. The introduced bioluciferase lux reporter enables easy, fast, and sensitive measurement of the promoter activity without cell lysis because the substrates of bioluminescent reaction are synthesized inside the bacterial cell, thereby allowing low-cost experiments. This protocol describes a high throughput technique to measure the promoter activity in Escherichia coli K-12 using the lux reporter system.

SARC-F as a Screening Tool for Sarcopenia and Possible Sarcopenia Proposed by AWGS 2019 in Hospitalized Older Adults

OBJECT

The SARC-F questionnaire is a sarcopenia screening tool. However, the validity of the SARC-F score ≥4 (SARC-F≥4) for the evaluation of sarcopenia in the hospital setting has not been investigated. This study investigated the validity of SARC-F≥4 as a screening tool for sarcopenia among hospitalized older adults.

DESIGN

Cross-sectional retrospective study.

SETTING

A university hospital.

PARTICIPANTS

This study included older adult patients (age ≥65 years) who were hospitalized at, and subsequently discharged from, the hospital between April and September 2019 and underwent a nutritional assessment by the nutrition support team during their hospitalization.

MEASUREMENTS

SARC-F was recorded at the time of admission, and the criteria specified by the Asia Working Group for Sarcopenia in 2019 (AWGS 2019) were applied to diagnose sarcopenia and possible sarcopenia. Appendicular muscle mass was estimated through validated equations, and three different models were developed for sarcopenia diagnosis. The sensitivity, specificity, and positive/negative likelihood ratios were calculated to analyze the accuracy of the SARC-F≥4 for sarcopenia and possible sarcopenia. Receiver-operating characteristic analyses were conducted to calculate the area under the curve (AUC).

RESULTS

In total, 1,689 patients (mean age: 77.2±7.3 years; male: 54.4%) were analyzed, and 636 patients (37.7%) had SARC-F≥4. Patients with SARC-F≥4 had a statistically significant higher prevalence of AWGS 2019-defined sarcopenia than patients with SARC-F <4 in the models (65.4-78.9% vs 40.9-45.2%, p<0.001). The sensitivity, specificity, and positive/negative likelihood ratios of SARC-F≥4 for sarcopenia and possible sarcopenia were 49.1-51.3%, 73.9-81.2%, and 1.88-2.72/0.60-0.69 and 48.0%, 84.5%, and 3.11/0.62, respectively. The AUC for sarcopenia and possible sarcopenia were 0.644-0.695 and 0.708, respectively. The AUC of SARC-F for possible sarcopenia was equivalent to or larger than that for sarcopenia (DeLong test p=0.438, 0.088, and <0.001 vs the three models).

CONCLUSIONS

SARC-F≥4 is suitable as a screening tool for sarcopenia in hospitalized older adults. SARC-F assessment could facilitate the detection and exclusion of sarcopenia at hospitalization and may lead to early adoption of a therapeutic and preventive approach.

Efficacy of Cutting Balloon Angioplasty for Chronic Total Occlusion of Femoropopliteal Arteries

BACKGROUND

Chronic total occlusion (CTO) of femoropopliteal artery (FP) continues to be a lesion subset where maintaining long-term patency after endovascular treatment is challenging. We evaluated the efficacy of cutting balloon angioplasty (CBA) for de novo FP-CTOs in patients with symptomatic lower limb ischemia.

METHODS

Seventy-three limbs of 67 symptomatic patients with de novo FP-CTOs successfully recanalized using CBA alone were enrolled in this study. Primary patency was defined as the absence of recurrent symptoms and no deterioration of the ankle-brachial index (ABI) >0.10 from the immediate postinterventional value.

RESULTS

The mean age was 73.5 ± 7.3 years, and 59.7% of patients had diabetes mellitus. Most lesions were classified as Trans-Atlantic Inter-Society Consensus II type C (n = 18; 24.7%) or type D (n = 44; 60.3%), with mean lesion and occluded lengths of 24.8 ± 11.4 and 17.8 ± 11.2 cm, respectively. No procedure-related adverse events occurred, except one distal embolization. The ABI significantly increased after intervention from 0.52 ± 0.12 to 0.80 ± 0.15 (P < 0.0001), with marked improvement in clinical symptoms (Rutherford stage: 2.7 ± 1.0 to 1.1 ± 1.2, P < 0.0001). The mean follow-up period was 31.2 ± 18.0 months, and the primary patency rates at 12 and 24 months were 75.3% and 60.6%, respectively. The independent predictive factors of failed patency were baseline hemoglobin A1c (P = 0.031, hazard radio [HR] 1.51 per 1%), occluded length ≥15 cm (P = 0.036, HR 2.90), and severe dissection (P = 0.033, HR 2.85). Vessel calcification and diameter did not affect primary patency.

CONCLUSIONS

CBA is a feasible option for endovascular treatment of FP-CTOs. Diabetic status, occlusion length, and severe dissection after CBA are independent negative predictors of long-term patency.

Burden of Premorbid Consumption of Texture Modified Diets in Daily Life on Nutritional Status and Outcomes of Hospitalization

OBJECTIVES

Due to the water-rich cooking process required to soften texture modified diets (TMDs), TMDs may have poorer nutrition. The aim of this study was to investigate the associations between daily premorbid TMD consumption and nutritional status at the time of hospitalization, and its burden on hospitalization outcomes.

DESIGN

Retrospective observational study.

SETTING

An academic hospital.

PARTICIPANTS

The cohort comprised 3,594 older adult patients aged ≥65 years admitted to the hospital.

MEASUREMENTS

Patients were interviewed on admission using a premorbid daily consumption meal form to determine whether the patient ate a TMD. Nutritional status was examined using nutritional screening tools (Mini-Nutritional Assessment Short Form [MNA-SF], Malnutrition Universal Screening Tool [MUST], Geriatric Nutritional Risk Index [GNRI]) and the European Society of Clinical Nutrition and Metabolism (ESPEN)-defined criteria of malnutrition at admission. Length of hospital stay (LOS) and in-hospital mortality were considered outcomes of hospitalization. Multivariate analyses were performed to detect associations between premorbid TMD consumption and nutritional status and outcomes.

RESULTS

The mean age of the subjects was 75.9±7.0 years, including 58% males. Overall, 110 (3.1%) patients consuming a premorbid TMD were identified. They were older (p<0.001), had poor nutritional status (lower MNA-SF score [p<0.001] and GNRI value [p<0.001], higher MUST score [p<0.001], and more prevalent ESPEN-defined malnutrition [61.8% vs. 14.0%, p<0.001] than did patients without a TMD. The mortality rate and LOS of patients with TMD was higher (7.3% vs. 2.9%, p=0.017) and longer (19 days vs. 8 days, p<0.001) than those without TMD. Multivariate analyses showed that TMD consumption was independently associated with poor nutritional status and prolonged LOS after adjusting confounders.

CONCLUSION

Daily consumption of a TMD during the premorbid period affects nutritional status at the time of hospitalization and outcomes. Further studies are necessary to investigate whether nutritional intervention can improve outcomes for people on a TMD.

Dimerization site 2 of the bacterial DNA-binding protein H-NS is required for gene silencing and stiffened nucleoprotein filament formation

The bacterial nucleoid-associated protein H-NS is a DNA-binding protein, playing a major role in gene regulation. To regulate transcription, H-NS silences genes, including horizontally acquired foreign genes. Escherichia coli H-NS is 137 residues long and consists of two discrete and independent structural domains: an N-terminal oligomerization domain and a C-terminal DNA-binding domain, joined by a flexible linker. The N-terminal oligomerization domain is composed of two dimerization sites, dimerization sites 1 and 2, which are both required for H-NS oligomerization, but the exact role of dimerization site 2 in gene silencing is unclear. To this end, we constructed a whole set of single amino acid substitution variants spanning residues 2 to 137. Using a well-characterized H-NS target, the slp promoter of the glutamic acid-dependent acid resistance (GAD) cluster promoters, we screened for any variants defective in gene silencing. Focusing on the function of dimerization site 2, we analyzed four variants, I70C/I70A and L75C/L75A, which all could actively bind DNA but are defective in gene silencing. Atomic force microscopy analysis of DNA-H-NS complexes revealed that all of these four variants formed condensed complexes on DNA, whereas WT H-NS formed rigid and extended nucleoprotein filaments, a conformation required for gene silencing. Single-molecule stretching experiments confirmed that the four variants had lost the ability to form stiffened filaments. We conclude that dimerization site 2 of H-NS plays a key role in the formation of rigid H-NS nucleoprotein filament structures required for gene silencing.

Regulatory role of XynR (YagI) in catabolism of xylonate in Escherichia coli K-12

The genome of Escherichia coli K-12 contains ten cryptic phages, altogether constituting about 3.6% of the genome in sequence. Among more than 200 predicted genes in these cryptic phages, 14 putative transcription factor (TF) genes exist, but their regulatory functions remain unidentified. As an initial attempt to make a breakthrough for understanding the regulatory roles of cryptic phage-encoded TFs, we tried to identify the regulatory function of CP4-6 cryptic prophage-encoded YagI with unknown function. After SELEX screening, YagI was found to bind mainly at a single site within the spacer of bidirectional transcription units, yagA (encoding another uncharacterized TF) and yagEF (encoding 2-keto-3-deoxy gluconate aldolase, and dehydratase, respectively) within this prophage region. YagEF enzymes are involved in the catabolism of xylose downstream from xylonate. We then designated YagI as XynR (regulator of xylonate catabolism), one of the rare single-target TFs. In agreement with this predicted regulatory function, the activity of XynR was suggested to be controlled by xylonate. Even though low-affinity binding sites of XynR were identified in the E. coli K-12 genome, they all were inside open reading frames, implying that the regulation network of XynR is still fixed within the CR4-6 prophage without significant influence over the host E. coli K-12.

Altered Distribution of RNA Polymerase Lacking the Omega Subunit within the Prophages along the Escherichia coli K-12 Genome

The RNA polymerase (RNAP) of Escherichia coli K-12 is a complex enzyme consisting of the core enzyme with the subunit structure α2ββ'ω and one of the σ subunits with promoter recognition properties. The smallest subunit, omega (the rpoZ gene product), participates in subunit assembly by supporting the folding of the largest subunit, β', but its functional role remains unsolved except for its involvement in ppGpp binding and stringent response. As an initial approach for elucidation of its functional role, we performed in this study ChIP-chip (chromatin immunoprecipitation with microarray technology) analysis of wild-type and rpoZ-defective mutant strains. The altered distribution of RpoZ-defective RNAP was identified mostly within open reading frames, in particular, of the genes inside prophages. For the genes that exhibited increased or decreased distribution of RpoZ-defective RNAP, the level of transcripts increased or decreased, respectively, as detected by reverse transcription-quantitative PCR (qRT-PCR). In parallel, we analyzed, using genomic SELEX (systemic evolution of ligands by exponential enrichment), the distribution of constitutive promoters that are recognized by RNAP RpoD holoenzyme alone and of general silencer H-NS within prophages. Since all 10 prophages in E. coli K-12 carry only a small number of promoters, the altered occupancy of RpoZ-defective RNAP and of transcripts might represent transcription initiated from as-yet-unidentified host promoters. The genes that exhibited transcription enhanced by RpoZ-defective RNAP are located in the regions of low-level H-NS binding. By using phenotype microarray (PM) assay, alterations of some phenotypes were detected for the rpoZ-deleted mutant, indicating the involvement of RpoZ in regulation of some genes. Possible mechanisms of altered distribution of RNAP inside prophages are discussed. IMPORTANCE The 91-amino-acid-residue small-subunit omega (the rpoZ gene product) of Escherichia coli RNA polymerase plays a structural role in the formation of RNA polymerase (RNAP) as a chaperone in folding the largest subunit (β', of 1,407 residues in length), but except for binding of the stringent signal ppGpp, little is known of its role in the control of RNAP function. After analysis of genomewide distribution of wild-type and RpoZ-defective RNAP by the ChIP-chip method, we found alteration of the RpoZ-defective RNAP inside open reading frames, in particular, of the genes within prophages. For a set of the genes that exhibited altered occupancy of the RpoZ-defective RNAP, transcription was found to be altered as observed by qRT-PCR assay. All the observations here described indicate the involvement of RpoZ in recognition of some of the prophage genes. This study advances understanding of not only the regulatory role of omega subunit in the functions of RNAP but also the regulatory interplay between prophages and the host E. coli for adjustment of cellular physiology to a variety of environments in nature.

Synthesis of Stereoselectively Functionalized Silacyclopentanes

An efficient approach to a variety of chiral silacyclopentanes having silicon stereogenic center based on the stereospecific transformations of C4 carbon stereogenic center of silacyclopentenols by ­Mitsunobu reaction or Tsuji–Trost reaction has been developed. The thus obtained substitution products can be converted into novel silacyclopentane triols, amines, and carboxylic acids in stereospecific manner.

Glutamate levels control HT22 murine hippocampal cell death by regulating biphasic patterns of Erk1/2 activation: role of metabolic glutamate receptor 5

Extracellular glutamate concentration is a critical determinant of neuronal cell fate. We recently demonstrated that HT22 murine hippocampal cell viability was reduced by exposure to high concentrations of glutamate, whereas low concentrations promoted cell survival. Extracellular signal-regulated kinase (Erk)1/2 activation by glutamate is important for both glutamate-induced cell death and survival. In this study, we investigated the role of glutamate-induced or hydrogen peroxide (H2O2)-induced Erk1/2 activation in HT22 cell fate determination. Glutamate and H2O2 treatment similarly induced early (&lt;1 h) Erk1/2 phosphorylation regardless of concentration. On the other hand, persistent Erk1/2 phosphorylation (16–24 h) was observed only in the presence of excess glutamate. Only the latter contributed to glutamate-induced cell death, which involved metabolic glutamate receptor 5. Our findings suggest that glutamate concentration modulates two distinct phases of Erk1/2 activation, which can explain the glutamate concentration-dependent determination of HT22 cell fate.

TEMPOL increases NAD(+) and improves redox imbalance in obese mice

Continuous energy conversion is controlled by reduction–oxidation (redox) processes. NAD⁺ and NADH represent an important redox couple in energy metabolism. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) is a redox-cycling nitroxide that promotes the scavenging of several reactive oxygen species (ROS) and is reduced to hydroxylamine by NADH. TEMPOL is also involved in NAD⁺ production in the ascorbic acid–glutathione redox cycle. We utilized the chemical properties of TEMPOL to investigate the effects of antioxidants and NAD⁺/NADH modulators on the metabolic imbalance in obese mice. Increases in the NAD⁺/NADH ratio by TEMPOL ameliorated the metabolic imbalance when combined with a dietary intervention, changing from a high-fat diet to a normal diet. Plasma levels of the superoxide marker dihydroethidium were higher in mice receiving the dietary intervention compared with a control diet, but were normalized with TEMPOL consumption. These findings provide novel insights into redox regulation in obesity.

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Redox imbalance: ROS generation and NADH accumulation, occurs in obesity.

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TEMPOL can normalize redox imbalance in various tissues.

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Whole body metabolism was activated by TEMPOL and dietary intervention.

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Redox regulation might be useful approaches for treating obesity.

Characterization of the YdeO regulon in Escherichia coli

Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD) system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions.

Temporospatial localization of dentine matrix protein 1 following direct pulp capping with calcium hydroxide in rat molars

AIM

To examine the temporospatial expression of dentine matrix protein 1 (DMP1; a noncollagenous protein involved in mineralized tissue formation), osteopontin (another noncollagenous protein detected during reparative dentinogenesis) and nestin (a marker of differentiating/differentiated odontoblasts), following direct pulp capping with calcium hydroxide in rat molars.

METHODOLOGY

The maxillary first molars of 8-week-old Wistar rats had their pulps exposed and capped with calcium hydroxide. The pulp-capped teeth were collected from 6 h to 14 days postoperatively and processed for immunohistochemistry for DMP1, osteopontin and nestin. Cell proliferation was monitored using 5-bromo-2'-deoxyuridine (BrdU) labelling.

RESULTS

The capped pulps initially exhibited superficial necrotic changes followed by the formation of new matrix and its mineralization. DMP1 immunoreactivity was observed in the matrix beneath the necrotic layer from 6 h onwards and present in the outer portion of the newly formed mineralized matrix from 7 days onwards. Osteopontin displayed a similar expression pattern, although it occupied a narrower area than DMP1 at 6 and 12 h. Nestin-immunoreactive cells appeared beneath the DMP1-immunoreactive area at 1 day, were distributed beneath the newly formed matrix at 5 days and exhibited odontoblast-like morphology by 14 days. BrdU-positive cells significantly increased at 2 and 3 days (P < 0.05) and then decreased.

CONCLUSIONS

The deposition of DMP1 at exposed pulp sites preceded the appearance of nestin-immunoreactive cells, active cell proliferation and new matrix formation after pulp capping with calcium hydroxide in rat molars, suggesting that DMP1 acts as a trigger of pulp repair. The colocalization of DMP1 and osteopontin suggests that these two proteins play complementary roles.

Dual cell protective mechanisms activated by differing levels of oxidative stress in HT22 murine hippocampal cells

Oxidative stress is recognized as one of the pathogenic mechanisms involved in neurodegenerative disease. However, recent evidence has suggested that regulation of cellular fate in response to oxidative stress appears to be dependent on the stress levels. In this study, using HT22 cells, we attempted to understand how an alteration in the oxidative stress levels would influence neuronal cell fate. HT22 cell viability was reduced with exposure to high levels of oxidative stress, whereas, low levels of oxidative stress promoted cell survival. Erk1/2 activation induced by a low level of oxidative stress played a role in this cell protective effect. Intriguingly, subtoxic level of H2O2 induced expression of a growth factor, progranulin (PGRN), and exogenous PGRN pretreatment attenuated HT22 cell death induced by high concentrations of H2O2 in Erk1/2-dependent manner. Together, our study indicates that two different cell protection mechanisms are activated by differing levels of oxidative stress in HT22 cells.