Bloodstream infection caused by Wickerhamiella pararugosa in a patient with intestinal obstruction: A case report.

The fungus Wickerhamiella pararugosa (Candida pararugosa) has been detected in various human organs but has rarely caused bloodstream infections. This report presents a case of central venous catheter-related bloodstream infection (CRBSI) of W. pararugosa in an adult. A female patient in her 80s was admitted to our facility for intestinal obstruction caused by colorectal cancer. The patient's ability to consume food was hindered, necessitating the insertion of a central venous catheter (CVC) into the internal jugular vein. On day 3 after admission, the patient developed a fever, prompting blood and CVC tip cultures to be performed. On day 5, yeast-like fungi were discovered in the blood cultures, and fosfluconazole (fluconazole [FLCZ] pro-drug) treatment was initiated. On day 8, yeast-like fungi were identified in both the blood and CVC tip cultures, leading to a diagnosis of CRBSI. The fungus was identified as W. pararugosa through biochemical and genetic characterization. This finding justified the use of micafungin (MCFG) for combination therapy. On day 17, the minimum inhibitory concentrations (MIC) for FLCZ and MCFG were 4-8 and 0.06 µg/mL, respectively. Accordingly, the treatment was changed to monotherapy with MCFG. After a 21-day treatment regimen, the patient was discharged on day 31. We present a case of CRBSI caused by W. pararugosa in an adult with intestinal obstruction. The notable increase in the MIC of FLCZ necessitated monotherapy with MCFG, which resulted in successful recovery of the patient.

One-step formation of three-dimensional interconnected T-shaped microstructures inside composites by orthogonal bidirectional self-assembly method.

The fillers inside a polymer matrix should typically be self-assembled in both the horizontal and vertical directions to obtain 3-dimentional (3D) percolation pathways, whereby the fields of application can be expanded and the properties of organic-inorganic composite films improved. Conventional dielectrophoresis techniques can typically only drive fillers to self-assemble in only one direction. We have devised a one-step dielectrophoresis-driven approach that effectively induces fillers self-assembly along two orthogonal axes, which results in the formation of 3D interconnected T-shaped iron microstructures (3D-T CIP) inside a polymer matrix. This approach to carbonyl iron powder (CIP) embedded in a polymer matrix results in a linear structure along the thickness direction and a network structure on the top surface of the film. The fillers in the polymer were controlled to achieve orthogonal bidirectional self-assembly using an external alternating current (AC) electric field and a non-contact technique that did not lead to electrical breakdown. The process of 3D-T CIP formation was observed in real time using in situ observation methods with optical microscopy, and the quantity and quality of self-assembly were characterized using statistical and fractal analysis. The process of fillers self-assembly along the direction perpendicular to the electric field was explained by finite element analogue simulations, and the results indicated that the insulating polyethylene terephthalate (PET) film between the electrode and the CIP/prepolymer suspension was the key to the formation of the 3D-T CIP. In contrast to the traditional two-step method of fabricating sandwich-structured film, the fabricated 3D-T CIP film with 3D electrically conductive pathways can be applied as magnetic field sensor.

A one-step electric field-induced self-assembly method was developed to efficiently control the self-assembly of fillers along two orthogonal axes to form three-dimensional interconnected T-shaped microstructure assembles of carbonyl iron powder inside a polymer matrix.

[Repeated Pericardial Effusion Leading to the Diagnosis of Synovial Sarcoma:Report of a Case].

The patient is a 76-year-old man. His chief complaint of chest pain led to a diagnosis of pericardial effusion of unknown cause, and pericardial drainage was performed. On the 30th day, chest pain appeared again. Echocardiography revealed a pericardial fluid reaccumulation and a substantial mass in the pericardial space. Surgical drainage was performed to find the cause. A hematoma/mass was present on the epicardium. The pericardial sac was filled with hematoma. The hematoma was removed, but part of the mass infiltrated close to the anterior descending branch of the left coronary artery, and removal of that part was abandoned. The intrapericardial hematoma and epicardium were submitted to pathology leading to the diagnosis of synovial sarcoma. The patient was discharged home 14 days after surgery.

Chk1 is a histone H3 threonine 11 kinase that regulates DNA damage-induced transcriptional repression.

DNA damage results in activation or suppression of transcription of a large number of genes. Transcriptional activation has been well characterized in the context of sequence-specific DNA-bound activators, whereas mechanisms of transcriptional suppression are largely unexplored. We show here that DNA damage rapidly reduces histone H3 Threonine 11 (T11) phosphorylation. This correlates with repression of genes, including cyclin B1 and cdk1. H3-T11 phosphorylation occurs throughout the cell cycle and is Chk1 dependent in vivo. Following DNA damage, Chk1 undergoes rapid chromatin dissociation, concomitant with reduced H3-T11 phosphorylation. Furthermore, we find that loss of H3-T11 phosphorylation correlates with reduced binding of the histone acetyltransferase GCN5 at cyclin B1 and cdk1 promoters and reduced H3-K9 acetylation. We propose a mechanism for Chk1 as a histone kinase, responsible for DNA-damage-induced transcriptional repression by loss of histone acetylation.

Plantainoside B in Bacopa monniera Binds to Aß Aggregates Attenuating Neuronal Damage and Memory Deficits Induced by Aß.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by dementia. The most characteristic pathological changes in AD brain include extracellular amyloid-ß (Aß) accumulation and neuronal loss. Particularly, cholinergic neurons in the nucleus basalis of Meynert are some of the first neuronal groups to degenerate; accumulating evidence suggests that Aß oligomers are the primary form of neurotoxicity. Bacopa monniera is a traditional Indian memory enhancer whose extract has shown neuroprotective and Aß-reducing effects. In this study, we explored the low molecular weight compounds from B. monniera extracts with an affinity to Aß aggregates, including its oligomers, using Aß oligomer-conjugated beads and identified plantainoside B. Plantainoside B exhibited evident neuroprotective effects by preventing Aß attachment on the cell surface of human induced pluripotent stem cell (hiPSC)-derived cholinergic neurons. Moreover, it attenuated memory impairment in mice that received intrahippocampal Aß injections. Furthermore, radioisotope experiments revealed that plantainoside B has affinity to Aß aggregates including its oligomers and brain tissue from a mouse model of Aß pathology. In addition, plantainoside B could delay the Aß aggregation rate. Accordingly, plantainoside B may exert neuroprotective effects by binding to Aß oligomers, thus interrupting the binding of Aß oligomers to the cell surface. This suggests its potential application as a theranostics in AD, simultaneously diagnostic and therapeutic drugs.

Development and external validation of the DOAT and DOATS scores: simple decision support tools to identify disease progression among nonelderly patients with mild/moderate COVID-19.

BACKGROUND: During the fifth wave of the coronavirus disease 2019 (COVID-19) pandemic in Japan, which took place between June and September 2021, a significant number of COVID-19 cases with deterioration occurred in unvaccinated individuals < 65 years old. However, the risk factors for COVID-19 deterioration in this specific population have not yet been determined. This study developed a prediction method to identify COVID-19 patients < 65 years old who are at a high risk of deterioration. METHODS: This retrospective study analyzed data from 1,675 patients < 65 years old who were admitted to acute care institutions in Fukushima with mild-to-moderate-1 COVID-19 based on the Japanese disease severity criteria prior to the fifth wave. For validation, 324 similar patients were enrolled from 3 hospitals in Yamagata. Logistic regression analyses using cluster-robust variance estimation were used to determine predictors of disease deterioration, followed by creation of risk prediction scores. Disease deterioration was defined as the initiation of medication for COVID-19, oxygen inhalation, or mechanical ventilation starting one day or later after admission. RESULTS: The patients whose condition deteriorated (8.6%) tended to be older, male, have histories of smoking, and have high body temperatures, low oxygen saturation values, and comorbidities, such as diabetes/obesity and hypertension. Stepwise variable selection using logistic regression to predict COVID-19 deterioration retained comorbidities of diabetes/obesity (DO), age (A), body temperature (T), and oxygen saturation (S). Two predictive scores were created based on the optimism-corrected regression coefficients: the DOATS score, including all of the above risk factors, and the DOAT score, which was the DOATS score without oxygen saturation. In the original cohort, the areas under the receiver operating characteristic curve (AUROCs) of the DOATS and DOAT scores were 0.81 (95% confidence interval [CI] 0.77-0.85) and 0.80 (95% CI 0.76-0.84), respectively. In the validation cohort, the AUROCs for each score were both 0.76 (95% CI 0.69-0.83), and the calibration slopes were both 0.80. A decision curve analysis confirmed the clinical practicability of both scores in the validation cohort. CONCLUSIONS: We established two prediction scores that can quickly evaluate the risk of COVID-19 deterioration in mild/moderate patients < 65 years old.

Human sapovirus propagation in human cell lines supplemented with bile acids.

Human sapoviruses (HuSaVs) cause acute gastroenteritis similar to human noroviruses. Although HuSaVs were discovered four decades ago, no HuSaV has been grown in vitro, which has significantly impeded the understanding of viral biology and the development of antiviral strategies. In this study, we identified two susceptible human cell lines, that originated from testis and duodenum, that support HuSaV replication and found that replication requires bile acids. HuSaVs replicated more efficiently in the duodenum cell line, and viral RNA levels increased up to ∼6 log10-fold. We also detected double-stranded RNA, viral nonstructural and structural proteins in the cell cultures, and intact HuSaV particles. We confirmed the infectivity of progeny viruses released into the cell culture supernatants by passaging. These results indicate the successful growth of HuSaVs in vitro. Additionally, we determined the minimum infectious dose and tested the sensitivities of HuSaV GI.1 and GII.3 to heat and ultraviolet treatments. This system is inexpensive, scalable, and reproducible in different laboratories, and can be used to investigate mechanisms of HuSaV replication and to evaluate antivirals and/or disinfection methods for HuSaVs.

Sulfated glycosaminoglycans mediate prion-like behavior of p53 aggregates.

Sulfated glycosaminoglycans (GAGs) such as heparan sulfate (HS) are heteropolysaccharides implicated in the pathology of protein aggregation diseases including localized and systemic forms of amyloidosis. Among subdomains of sulfated GAGs, highly sulfated domains of HS, called HS S-domains, have been highlighted as being critical for HS function in amyloidoses. Recent studies suggest that the tumor suppressor p53 aggregates to form amyloid fibrils and propagates in a prion-like manner; however, molecules and mechanisms that are involved in the prion-like behavior of p53 aggregates have not been addressed. Here, we identified sulfated GAGs as molecules that mediate prion-like behavior of p53 aggregates. Sulfated GAGs at the cell surface were required for cellular uptake of recombinant and cancer cell-derived p53 aggregates and extracellular release of p53 from cancer cells. We further showed that HS S-domains accumulated within p53 deposits in human ovarian cancer tissues, and enzymatic remodeling of HS S-domains by Sulf-2 extracellular sulfatase down-regulated cellular uptake of p53 aggregates. Finally, sulfated GAG-dependent cellular uptake of p53 aggregates was critical for subsequent extracellular release of the aggregates and gain of oncogenic function in recipient cells. Our work provides a mechanism of prion-like behavior of p53 aggregates and will shed light on sulfated GAGs as a common mediator of prions.

Predictors of life-space mobility in patients with fracture 3 months after discharge from convalescent rehabilitation ward: a prospective longitudinal study.

[Purpose] To identify predictors of life-space mobility in patients with fracture three months after discharge from convalescent rehabilitation ward. [Participants and Methods] This is a prospective longitudinal study that included patients aged 65 or older with a fracture who were scheduled for discharge home from the convalescent rehabilitation ward. Baseline measurements included sociodemographic variables (age, gender, and disease), the Falls Efficacy Scale-International, maximum walking speed, the Timed Up & Go test, the Berg Balance Scale, the modified Elderly Mobility Scale, the Functional Independence Measure, the revised version of Hasegawa's Dementia Scale, and the Vitality Index up to two weeks before discharge. As a follow-up, the life-space assessment was measured three months after discharge. In the statistical analysis, multiple linear and logistic regression analyses were performed with the life-space assessment score and the life-space level of "places outside your town" as dependent variables. [Results] The Falls Efficacy Scale-International, the modified Elderly Mobility Scale, age, and gender were selected as predictors in the multiple linear regression analysis, whereas in the multiple logistic regression analysis, the Falls Efficacy Scale-International, age, and gender were selected as predictors. [Conclusion] Our study emphasized the importance of fall-related self-efficacy and motor function for life-space mobility. The findings of this study suggest that when considering post-discharge living, therapists should conduct an appropriate assessment and adequate planning.

Design and Synthesis of 6-O-Phosphorylated Heparan Sulfate Oligosaccharides to Inhibit Amyloid ß Aggregation.

Dysregulation of amyloidogenic proteins and their abnormal processing and deposition in tissues cause systemic and localized amyloidosis. Formation of amyloid ß (Aß) fibrils that deposit as amyloid plaques in Alzheimer's disease (AD) brains is an earliest pathological hallmark. The polysulfated heparan sulfate (HS)/heparin (HP) is one of the non-protein components of Aß deposits that not only modulates Aß aggregation, but also acts as a receptor for Aß fibrils to mediate their cytotoxicity. Interfering with the interaction between HS/HP and Aß could be a therapeutic strategy to arrest amyloidosis. Here we have synthesized the 6-O-phosphorylated HS/HP oligosaccharides and reported their competitive effects on the inhibition of HP-mediated Aß fibril formation in vitro using a thioflavin T fluorescence assay and a tapping mode atomic force microscopy.

Real-world clinical outcomes of treatment with casirivimab-imdevimab among patients with mild-to-moderate coronavirus disease 2019 during the Delta variant pandemic.

Background: Mutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may reduce the efficacy of neutralizing monoclonal antibody therapy against coronavirus disease 2019 (COVID-19). We here evaluated the efficacy of casirivimab-imdevimab in patients with mild-to-moderate COVID-19 during the Delta variant surge in Fukushima Prefecture, Japan. Methods: We enrolled 949 patients with mild-to-moderate COVID-19 who were admitted to hospital between July 24, 2021 and September 30, 2021. Clinical deterioration after admission was compared between casirivimab-imdevimab users (n = 314) and non-users (n = 635). Results: The casirivimab-imdevimab users were older (P < 0.0001), had higher body temperature (≥ 38°C) (P < 0.0001) and greater rates of history of cigarette smoking (P = 0.0068), hypertension (P = 0.0004), obesity (P < 0.0001), and dyslipidemia (P < 0.0001) than the non-users. Multivariate logistic regression analysis demonstrated that receiving casirivimab-imdevimab was an independent factor for preventing deterioration (odds ratio 0.448; 95% confidence interval 0.263-0.763; P = 0.0023). Furthermore, in 222 patients who were selected from each group after matching on the propensity score, deterioration was significantly lower among those receiving casirivimab-imdevimab compared to those not receiving casirivimab-imdevimab (7.66% vs 14.0%; p = 0.021). Conclusion: This real-world study demonstrates that casirivimab-imdevimab contributes to the prevention of deterioration in COVID-19 patients after hospitalization during a Delta variant surge.

Current Status and Challenges of Analytical Methods for Evaluation of Size and Surface Modification of Nanoparticle-Based Drug Formulations.

The present review discusses the current status and difficulties of the analytical methods used to evaluate size and surface modifications of nanoparticle-based pharmaceutical products (NPs) such as liposomal drugs and new SARS-CoV-2 vaccines. We identified the challenges in the development of methods for (1) measurement of a wide range of solid-state NPs, (2) evaluation of the sizes of polydisperse NPs, and (3) measurement of non-spherical NPs. Although a few methods have been established to analyze surface modifications of NPs, the feasibility of their application to NPs is unknown. The present review also examined the trends in standardization required to validate the size and surface measurements of NPs. It was determined that there is a lack of available reference materials and it is difficult to select appropriate ones for modified NP surface characterization. Research and development are in progress on innovative surface-modified NP-based cancer and gene therapies targeting cells, tissues, and organs. Next-generation nanomedicine should compile studies on the practice and standardization of the measurement methods for NPs to design surface modifications and ensure the quality of NPs.

In vivo comparison of dl-sotalol-induced electrocardiographic responses among halothane anesthesia, isoflurane anesthesia with nitrous oxide, and conscious state.

We compared dl-sotalol-induced electrocardiographic responses in intact dogs using a repeated-measures design among 1% halothane anesthesia, 1.5% isoflurane anesthesia with nitrous oxide (N2O), and conscious state to clarify influences of the anesthetics (n = 4). Basal PR interval was longer in halothane than either in isoflurane with N2O or in conscious state, reflecting sympathetic nerve suppression for the atrioventricular node by halothane. Both anesthetics exhibited longer basal QRS width than conscious state, suggesting their ventricular INa inhibition. Also, both anesthetics showed longer basal QT interval, QTcF and Tpeak-Tend than conscious state, indicating their ventricular IKr inhibition. Meanwhile, dl-sotalol prolonged PR interval similarly in isoflurane with N2O and in conscious state, which was less great in halothane, suggesting further sympathetic nerve suppression for the atrioventricular node might be limited in halothane. dl-Sotalol prolonged QT interval and QTcF >3 times greater in either of the anesthetics than in conscious state; moreover, dl-sotalol prolonged Tpeak-Tend similarly in both anesthetics, but hardly altered it in conscious state; indicating isoflurane with N2O as well as halothane may have reduced the repolarization reserve to increase the sensitivity of ventricle toward IKr suppression. Thus, isoflurane with nitrous oxide could be useful for in vivo IKr assay like halothane.

In vivo analysis of concentration-dependent effects of halothane or isoflurane inhalation on the electrocardiographic and hemodynamic variables in dogs.

We assessed concentration-dependent effects of halothane or isoflurane inhalation on the electrocardiographic and hemodynamic variables using a cross-over design in intact beagle dogs (n = 4). Elevation of inhaled halothane from 1.0% to 2.0% or isoflurane from 1.5% to 2.5% decreased the mean blood pressure and prolonged the QRS width without significantly altering the heart rate, PR interval or QT interval. However, the observed changes disappeared after regressions of both anesthetic conditions to their initial settings. These results indicate that hypotension-induced, reflex-mediated increase of sympathetic tone may have counterbalanced the direct negative chronotropic, dromotropic and repolarization slowing effects of the anesthetics.

Mechanisms of aggregation and fibril formation of the amyloidogenic N-terminal fragment of apolipoprotein A-I.

The N-terminal (1-83) fragment of the major constituent of plasma high-density lipoprotein, apolipoprotein A-I (apoA-I), strongly tends to form amyloid fibrils, leading to systemic amyloidosis. Here, using a series of deletion variants, we examined the roles of two major amyloidogenic segments (residues 14-22 and 50-58) in the aggregation and fibril formation of an amyloidogenic G26R variant of the apoA-I 1-83 fragment (apoA-I 1-83/G26R). Thioflavin T fluorescence assays and atomic force microscopy revealed that elimination of residues 14-22 completely inhibits fibril formation of apoA-I 1-83/G26R, whereas Δ32-40 and Δ50-58 variants formed fibrils with markedly reduced nucleation and fibril growth rates. CD measurements revealed structural transitions from random coil to ß-sheet structures in all deletion variants except for the Δ14-22 variant, indicating that residues 14-22 are critical for the ß-transition and fibril formation. Thermodynamic analysis of the kinetics of fibril formation by apoA-I 1-83/G26R indicated that both nucleation and fibril growth are enthalpically unfavorable, whereas entropically, nucleation is favorable, but fibril growth is unfavorable. Interestingly, the nucleation of the Δ50-58 variant was entropically unfavorable, indicating that residues 50-58 entropically promote the nucleation step in fibril formation of apoA-I 1-83/G26R. Moreover, a residue-level structural investigation of apoA-I 1-83/G26R fibrils with site-specific pyrene labeling indicated that the two amyloidogenic segments are in close proximity to form an amyloid core structure, whereas the N- and C-terminal tail regions are excluded from the amyloid core. These results provide critical insights into the aggregation mechanism and fibril structure of the amyloidogenic N-terminal fragment of apoA-I.

The Accumulation of Heparan Sulfate S-Domains in Kidney Transthyretin Deposits Accelerates Fibril Formation and Promotes Cytotoxicity.

The highly sulfated domains of heparan sulfate (HS), alias HS S-domains, are made up of repeated trisulfated disaccharide units [iduronic acid (2S)-glucosamine (NS, 6S)] and are selectively remodeled by extracellular endoglucosamine 6-sulfatases (Sulfs). Although HS S-domains are critical for signal transduction of several growth factors, their roles in amyloidoses are not yet fully understood. Herein, we found HS S-domains in the kidney of a patient with transthyretin amyloidosis. In in vitro assays with cells stably expressing human Sulfs, heparin, a structural analog of HS S-domains, promoted aggregation of transthyretin in an HS S-domain-dependent manner. Interactions of cells with transthyretin fibrils and cytotoxicity of these fibrils also depended on HS S-domains at the cell surface. Furthermore, glypican-5, encoded by the susceptibility gene for nephrotic syndrome GPC5, was found to be accumulated in the transthyretin amyloidosis kidney. Our study, thus, provides a novel insight into the pathologic roles of HS S-domains in amyloidoses, and we propose that enzymatic remodeling of HS chains by Sulfs may offer an effective approach to inhibiting formation and cytotoxicity of amyloid fibrils.

[Bladder-Infiltrating Sigmoid Colon Cancer Successfully Treated with Neoadjuvant Chemotherapy and Radical Resection-A Case Report].

A 71-year-old man presented with the chief complaints of constipation, melena, and weight loss, and sigmoid colon cancer was suspected on lower gastrointestinal endoscopy. The cancer was diagnosed as RAS wild type adenocarcinoma(tub2)on biopsy. Abdominal contrast-enhanced CT revealed a mass with a maximum diameter of 55mm in the sigmoid colon; therefore, bladder infiltration was suspected. The Group 1 lymph nodes were bulky, with a maximum diameter of 50 mm, and No. 253 lymph node was enlarged. No fistulas were found on cystoscopy. The sigmoid colon cancer was cT4b(bladder), N3, M0, cStage Ⅲc. After performing a colostomy, neoadjuvant chemotherapy with mFOLFOX6 plus panitumumab was started. Radical surgery was performed after 3 courses of chemotherapy. The clinical treatment effect was PR, and the final histopathologi- cal examination revealed ypT3, ypN0(0/17), R0, ypStageⅡa. The therapeutic effect was Grade 2a. Postoperative adjuvant chemotherapy was performed for 6 months with mFOLFOX, and there have been no signs of cancer recurrence for 9 postoperative months. We experienced a case of colon cancer with suspected bladder infiltration, successfully treated with neoadjuvant chemotherapy and radical surgery.

[A Case of Long-Term Survival in a Patient with Advanced Gastric Cancer with Virchow's Lymph Node Metastasis Which Received Multidisciplinary Treatment].

We report a case of long-term survival in a 75-year-old male with advanced gastric cancer and Virchow's lymph node metastasis[cT3N3M1(LYM)H0P0, cStage Ⅳ]which received multidisciplinary treatment. Over 1 year and 6 months, 5 courses of S-1 plus CDDP, 14 courses of S-1 plus docetaxel, and 3 courses of S-1 plus CPT-11 were administered. Following chemotherapy, FDG-PET/CT showed FDG uptake only in the primary tumor and regional lymph nodes. Total gastrectomy and D2 dissection were performed. The pathological diagnosis was Type 5, 55×50 mm, L, Less, tub1>tub2, T3, int, INF b, ly2, v1, pPM0, pDM0, pN2(3/29), HER2(-). S-1 was used as adjuvant chemotherapy. Four years and 7 months after resection, cervical lymph node swelling was detected. The cervical lymph node was resected, followed by radiotherapy administration(56 Gy/28 Fr). No relapse occurred, and the patient has survived more than 7 years and 1 month and 8 years and 11 months after conversion surgery and diagnosis, respectively.

[A Case Report of Accessory Breast Cancer in the Right Axillary Region].

An 80-year-old woman visited a previous hospital complaining of a lump in the right axillary region. Because it was suspected of accessory breast cancer from the findings of image inspection, she was referred for surgery. Based on mammography and ultrasonography, both bilateral mammary glands were reported normal, but an irregular mass was found in the right axillary region. Resection biopsy showed adenocarcinoma like invasive ductal carcinoma. In addition, ER and PgR were positive. With a preoperative diagnosis of accessory breast cancer, she underwent wide local resection of the right axillary region with lymph-node dissection(Level Ⅰ), and local pedicle flap formation. Histopathological findings revealed that the tumor was composed of invasive ductal carcinoma. The center of tumor was consisted of ductal tissue discontinuous with normal mammary gland. So, a diagnosis of accessory breast cancer in the right axillary region was confirmed. She is currently in recurrence-free survival. Accessory breast cancer is relatively rare. We report a case of accessory breast cancer in the axillary region with some review of the literature.

Biophysical Mechanism of Protein Export by Bacterial Type III Secretion System.

Type III secretion system (T3SS) is a protein injection nano-machine consisting of syringe and needle-like structure spanning bacterial inner and outer membranes. Bacteria insert the tip of T3SS needle to host cell membranes, and deliver effector proteins directly into host cells via T3SS to prime the host cell environment for infection. Thus inhibition of T3SS would be a potent strategy for suppressing bacterial infection. We previously demonstrated that T3SS needle rotates by proton-motive force (PMF) with the same mechanism as two evolutionally related rotary protein motors, flagellum and ATP synthase (FASEB J., 27, 2013, Ohgita et al.). Inhibition of needle rotation resulted in suppression of effector secretion, indicating the requirement of needle rotation for effector export. Simulation analysis of protein export by the T3SS needle suggests the importance of a hydrophobic helical groove formed by the conserved aromatic residue in the needle components. Based on these results, we have proposed a novel model of protein export by the T3SS needle, in which effector proteins are exported by PMF-dependent needle rotation oppositely to the hydrophobic helical groove in the needle. Quantitative examinations of the correlation between the speeds of T3SS rotation and the amount of effector export support this model. In this review, we summarize our current understanding of T3SS, and discuss our novel model of the protein export mechanism of T3SS based on the needle rotation.