A selective antibiotic for Lyme disease.

Lyme disease is on the rise. Caused by a spirochete Borreliella burgdorferi, it affects an estimated 500,000 people in the United States alone. The antibiotics currently used to treat Lyme disease are broad spectrum, damage the microbiome, and select for resistance in non-target bacteria. We therefore sought to identify a compound acting selectively against B. burgdorferi. A screen of soil micro-organisms revealed a compound highly selective against spirochetes, including B. burgdorferi. Unexpectedly, this compound was determined to be hygromycin A, a known antimicrobial produced by Streptomyces hygroscopicus. Hygromycin A targets the ribosomes and is taken up by B. burgdorferi, explaining its selectivity. Hygromycin A cleared the B. burgdorferi infection in mice, including animals that ingested the compound in a bait, and was less disruptive to the fecal microbiome than clinically relevant antibiotics. This selective antibiotic holds the promise of providing a better therapeutic for Lyme disease and eradicating it in the environment.

The antibiotic darobactin mimics a ß-strand to inhibit outer membrane insertase.

Antibiotics that target Gram-negative bacteria in new ways are needed to resolve the antimicrobial resistance crisis1-3. Gram-negative bacteria are protected by an additional outer membrane, rendering proteins on the cell surface attractive drug targets4,5. The natural compound darobactin targets the bacterial insertase BamA6-the central unit of the essential BAM complex, which facilitates the folding and insertion of outer membrane proteins7-13. BamA lacks a typical catalytic centre, and it is not obvious how a small molecule such as darobactin might inhibit its function. Here we resolve the mode of action of darobactin at the atomic level using a combination of cryo-electron microscopy, X-ray crystallography, native mass spectrometry, in vivo experiments and molecular dynamics simulations. Two cyclizations pre-organize the darobactin peptide in a rigid ß-strand conformation. This creates a mimic of the recognition signal of native substrates with a superior ability to bind to the lateral gate of BamA. Upon binding, darobactin replaces a lipid molecule from the lateral gate to use the membrane environment as an extended binding pocket. Because the interaction between darobactin and BamA is largely mediated by backbone contacts, it is particularly robust against potential resistance mutations. Our results identify the lateral gate as a functional hotspot in BamA and will allow the rational design of antibiotics that target this bacterial Achilles heel.

Author Correction: A new antibiotic selectively kills Gram-negative pathogens.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A new antibiotic selectively kills Gram-negative pathogens.

The current need for novel antibiotics is especially acute for drug-resistant Gram-negative pathogens1,2. These microorganisms have a highly restrictive permeability barrier, which limits the penetration of most compounds3,4. As a result, the last class of antibiotics that acted against Gram-negative bacteria was developed in the 1960s2. We reason that useful compounds can be found in bacteria that share similar requirements for antibiotics with humans, and focus on Photorhabdus symbionts of entomopathogenic nematode microbiomes. Here we report a new antibiotic that we name darobactin, which was obtained using a screen of Photorhabdus isolates. Darobactin is coded by a silent operon with little production under laboratory conditions, and is ribosomally synthesized. Darobactin has an unusual structure with two fused rings that form post-translationally. The compound is active against important Gram-negative pathogens both in vitro and in animal models of infection. Mutants that are resistant to darobactin map to BamA, an essential chaperone and translocator that folds outer membrane proteins. Our study suggests that bacterial symbionts of animals contain antibiotics that are particularly suitable for development into therapeutics.

Evybactin is a DNA gyrase inhibitor that selectively kills Mycobacterium tuberculosis.

The antimicrobial resistance crisis requires the introduction of novel antibiotics. The use of conventional broad-spectrum compounds selects for resistance in off-target pathogens and harms the microbiome. This is especially true for Mycobacterium tuberculosis, where treatment requires a 6-month course of antibiotics. Here we show that a novel antimicrobial from Photorhabdus noenieputensis, which we named evybactin, is a potent and selective antibiotic acting against M. tuberculosis. Evybactin targets DNA gyrase and binds to a site overlapping with synthetic thiophene poisons. Given the conserved nature of DNA gyrase, the observed selectivity against M. tuberculosis is puzzling. We found that evybactin is smuggled into the cell by a promiscuous transporter of hydrophilic compounds, BacA. Evybactin is the first, but likely not the only, antimicrobial compound found to employ this unusual mechanism of selectivity.

Impact of timing of urinary drainage on clinical outcomes in patients with obstructive pyelonephritis associated with upper urinary tract stones: a propensity score-matched analysis.

OBJECTIVE: We aimed to assess the impact of the timing of urinary drainage on clinical outcomes in patients with obstructive pyelonephritis (OPN) associated with upper urinary tract (UUT) stones. METHODS: We retrospectively evaluated the multicenter dataset of 240 patients with OPN associated with UUT stones who underwent urinary drainage. We divided the patients into two groups depending on the timing of urinary drainage; emergency drainage, defined as within 12 h from admission, and delayed drainage, defined as between 12 and 48 h from admission. The outcomes were the length of hospital stay, time to leukocyte normalization, and time to body temperature normalization. One-to-two propensity score matching (PSM) was applied to minimize the effect of confounders between the two groups. Subsequently, predictive patient factors for emergency drainage were analyzed using the logistic regression model. RESULTS: Only the time from admission to normal body temperature was significantly shorter in the emergency drainage group when compared with the delayed drainage group (median: 2 vs. 3 days; p = 0.02), while there was no difference in time from drainage to body temperature normalization between the two groups. On multivariable analysis, high pretreatment C-reactive protein (CRP) was associated with implementing emergency drainage within 12 h. CONCLUSIONS: The timing of urinary drainage was only associated with the duration of high fever, but it did not affect the postdrainage course. Emergency urinary drainage is more likely to be performed in severe patients, such as high pretreatment CRP.

Associations between early changes in the neutrophil-to-lymphocyte ratio after radical nephroureterectomy and treatment outcomes.

OBJECTIVES: This study explored the impacts of peri-operative changes in the neutrophil-to-lymphocyte ratio (NLR) on the survival rate after radical nephroureterectomy. METHODS: This retrospective analysis included a multicentric cohort of patients diagnosed with upper tract urothelial carcinoma (UTUC) who had undergone radical nephroureterectomy from 2012 to 2021. We assessed the preoperative NLR, postoperative NLR, delta-NLR (difference between postoperative and preoperative NLRs), and NLR change (ratio of postoperative to preoperative NLR). Additionally, patients were categorized according to increases in their preoperative and/or postoperative NLRs. Associations of survival with peri-operative changes in the NLR were investigated using Cox multivariate regression models. RESULTS: A total of 488 patients were included in the study, with a median age of 73 years. Among the patients, 105 (21.5%) exhibited elevated preoperative and postoperative NLRs, 88 (18.0%) exhibited elevated preoperative NLR only, 53 (10.9%) exhibited elevated postoperative NLR only, and 242 (49.6%) exhibited normal NLRs. Multivariate analysis indicated significant negative correlations between both preoperative and postoperative increased NLRs and oncological outcomes, including nonurothelial tract recurrence-free survival and cancer-specific survival (hazard ratio [HR]: 1.65, P = 0.017; HR: 2.12, P = 0.014, respectively). CONCLUSION: This is the first study to evaluate the association between peri-operative changes in the NLR and the outcomes of patients with UTUC who underwent radical nephroureterectomy. Patients with elevated NLRs at both time points experienced considerably worse outcomes. Further research should explore whether increases in the NLR during long-term follow-up could indicate impending disease recurrence.

Association between comorbidities and survival in patients with metastatic urothelial carcinoma treated with pembrolizumab.

BACKGROUND: This study aims to investigate the relationship between comorbidities and survival in patients with mUC treated with pembrolizumab as a second-line treatment. METHODS: From February 2018 to October 2021, we analyzed the data of 185 consecutive patients with metastatic UC who received pembrolizumab as second-line therapy at The Jikei University Hospital and five affiliated hospitals. We used the Charlson Comorbidity Index (CCI) to assess the comorbidities. The outcomes of interest were progression-free survival (PFS) and overall survival (OS). To compare the survival differences, inverse probability of treatment weighting (IPTW)-adjusted Kaplan-Meier curves and the IPTW-adjusted Cox regression hazards model were used. RESULTS: After IPTW adjustment, patient characteristics were well-balanced between patients with high CCI and those with low CCI. The IPTW-adjusted Kaplan-Meier curves of PFS and OS based on CCI revealed that the patients with high CCI (2 or more) had a shorter PFS (median, 1.6 vs. 2.8 months) and a shorter OS (median, 12.4 vs. 18.8 months) (0-1). Similarly, in the IPTW-adjusted Cox regression hazards model, patients with high CCI had significantly shorter PFS [HR, 1.84 (95% CI 1.26-2.68; p = 0.002)] and OS [HR, 1.98 (95% CI 1.20-3.27; p = 0.008)] than those with lower CCI. CONCLUSIONS: High CCI was associated with a higher risk of disease progression as well as overall mortality in mUC patients treated with second-line pembrolizumab.

Real-world outcomes of adjuvant immunotherapy candidates with upper tract urothelial carcinoma: results of a multicenter cohort study.

BACKGROUND: Recent clinical trials have reported improved disease-free survival rates of patients with stage pT3-4/ypT2-4 or pN + upper tract urothelial carcinoma (UTUC) on adjuvant nivolumab therapy. However, the appropriateness of the patient selection criteria used in clinical practice remains uncertain. METHODS: We retrospectively analyzed 895 patients who underwent nephroureterectomy to treat UTUC. The patients were divided into two groups: grade pT3-4 and/or pN + without neoadjuvant chemotherapy (NAC) or grade ypT2-4 and/or ypN + on NAC (adjuvant immunotherapy candidates) and others (not candidates for adjuvant immunotherapy). Kaplan-Meier curves were drawn to assess the oncological outcomes, including recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Cox proportional hazards models were used to identify significant prognostic factors for oncological outcomes. RESULTS: The Kaplan-Meier curves revealed notably inferior RFS, CSS, and OS of patients who were candidates for adjuvant immunotherapy. Multivariate analysis revealed that pathological T and N grade and lymphovascular invasion (LVI) status were independent risk factors for poor RFS, CSS, and OS. CONCLUSION: In total, 44.8% of patients were candidates for adjuvant immunotherapy. In addition to pathological T and N status, LVI was a significant predictor of survival, and may thus play a pivotal role in the selection of patients eligible for adjuvant immunotherapy.

Prognostic significance of subclassifying pathological T3 upper tract urothelial carcinoma: Results from a multicenter cohort study.

OBJECTIVE: The population with pathological T3 (pT3) upper tract urothelial carcinoma (UTUC) is heterogeneous, thereby making prognostication challenging. We assessed the clinical ramifications of subclassifying pT3 UTUC after nephroureterectomy. METHODS: We conducted a retrospective analysis including 308 patients who underwent nephroureterectomy for pT3N0-1M0 UTUC. pT3 was subclassified into pT3a and pT3b based on invasion of the peripelvic and/or periureteral fat. Cox's proportional hazard models were utilized to determine the significant prognosticators of oncological outcomes, encompassing intravesical recurrence-free survival, recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival. RESULTS: Multivariate analysis elucidated that pT3b status, pathological N1 status, and lymphovascular invasion status were independent risk factors for an unfavorable RFS and CSS. Although the RFS and CSS of patients with pT3b UTUC were superior to those in patients with pT4 UTUC, no significant disparities were detected between patients with pT3a and pT2. CONCLUSION: Our findings demonstrate that pT3 UTUC with peripelvic/periureteral fat invasion is independently associated with metastasis and cancer-specific death after nephroureterectomy. These findings provide patients and physicians with invaluable insight into the risk for disease progression in pT3 UTUC patients.

The clinical impact of ureteroscopy for upper tract urothelial carcinoma: A multicenter study.

BACKGROUND: With the development of kidney-sparing surgery and neoadjuvant chemotherapy, ureteroscopic biopsy (URSBx) has become important for the management of upper tract urothelial carcinoma (UTUC). METHODS: We retrospectively analyzed data from 744 patients with UTUC who underwent radical nephroureterectomy (RNU), stratified into no ureteroscopy (URS), URS alone, and URSBx groups. Intravesical recurrence-free survival (IVRFS) was examined using the Kaplan-Meier method. We conducted Cox regression analyses to identify risk factors for IVR. We investigated differences between clinical and pathological staging to assess the ability to predict the pathological tumor stage and grade of RNU specimens. RESULTS: Kaplan-Meier curves and multivariate Cox regression revealed significantly more IVR and inferior IVRFS in patients who underwent URS and URSBx. Superficial, but not invasive, bladder cancer recurrence was more frequent in the URS and URSBx groups than in the no URS group. Clinical and pathological staging agreed for 55 (32.4%) patients. Downstaging occurred for 48 (28.2%) patients and clinical understaging occurred for 67 (39.4%) patients. Upstaging to muscle-invasive disease occurred for 39 (35.8%) of 109 patients with ≤cT1 disease. Clinical and pathological grading were similar for 72 (42.3%) patients. Downgrading occurred for 5 (2.9%) patients, and clinical undergrading occurred for 93 (54.7%) patients. CONCLUSION: URS and URSBx instrumentation will be risk factors for superficial, but not invasive, bladder cancer recurrence. Clinical understaging/undergrading and upstaging to muscle-invasive disease occurred for a large proportion of patients with UTUC who underwent RNU. These data emphasize the challenges involved in accurate UTUC staging and grading.

Effectiveness of pembrolizumab in trial-ineligible patients with metastatic urothelial carcinoma.

BACKGROUND: The KEYNOTE-045 trial showed that pembrolizumab therapy improved the survival of patients with advanced urothelial carcinoma (UC). However, its effectiveness in trial-ineligible patients remains unclear. MATERIALS AND METHODS: We conducted a multicenter retrospective study to evaluate the effectiveness of pembrolizumab in patients with metastatic UC who were trial-ineligible. The data of 164 consecutive patients with platinum-treated metastatic UC who received pembrolizumab as second-line therapy were analyzed. Trial eligibility was assessed using the KEYNOTE-045 criteria. Inverse probability of treatment weighting (IPTW) was used to balance patient characteristics. Overall survival (OS) and progression-free survival (PFS) were examined using the IPTW-adjusted Kaplan-Meier method. IPTW-adjusted restricted mean survival times (RMSTs) were compared between ineligible and eligible patients. RESULTS: Seventy-five patients (45.7%) were classified as ineligible based on the KEYNOTE-045 criteria. Baseline hemoglobin concentration of less than 9.0 g/dL was the most common reason for trial protocol violation (N = 23 [14.0%]). An IPTW-adjusted logistic regression model showed that the trial-eligibility was not significantly associated with objective response (OR: 0.65, 95% CI: 0.32 to 1.29, P = 0.22). Ineligible patients had similar RMST for PFS (difference: 3.8 months, 95% CI: -1.6 to 9.3, P = 0.17) and RMST for OS (difference: 1.4 months, 95% CI: -5.4 to 8.2, P = 0.93) compared with eligible patients. CONCLUSIONS: This study suggests that the effectiveness of pembrolizumab may be retained in ineligible patients with platinum-treated metastatic UC. Expanding trial eligibility criteria for these patients may be beneficial.

Phenomenological interpretations of the mechanism for the concentration-dependent positive effect of antibiotic lincomycin on Streptomyces coelicolor A3(2).

The antibiotic lincomycin binds to the 23S ribosomal RNA peptidyl transferase loop region to inhibit protein synthesis. However, lincomycin can also stimulate the growth and secondary metabolism of actinomycetes in a concentration-dependent manner. In Streptomyces coelicolor A3(2), lincomycin stimulates the production of the blue-pigmented antibiotic actinorhodin at concentrations below the minimum inhibitory concentration. To better understand the molecular mechanism underlying these concentration-dependent positive effects, this study investigated how the target molecule, the ribosome, undergoes dynamic changes in the presence of lincomycin and explored the ribosome-related factors involved. Lincomycin, at a concentration that stimulates actinorhodin production of S. coelicolor A3(2), could restore temporarily arrested ribosome function by utilizing ribosome-related proteins and translation factors, presumably under the control of the transcription factor WblC protein that confers intrinsic resistance to multiple translation-inhibiting antibiotics, to eventually produce stable and active ribosomes even during the late growth phase. This qualitatively and quantitatively positive ribosome alteration can be advantageous for producing actinorhodin biosynthetic enzymes. A series of gene expression and biochemical analyses revealed that lincomycin at the concentration that induces ribosomal stabilization in S. coelicolor A3(2) could influence the localization of the 20S proteasome-related proteins, resulting in reduced proteasome activity. These findings suggest that the functional analysis of 20S proteasome represents a potential pivotal challenge for understanding the molecular mechanism of ribosome stabilization induced by lincomycin. Therefore, as lincomycin can dynamically alter its target molecule, the ribosome, we discuss the future issues and prospects for an increased understanding of the concentration-dependent properties of antibiotics. IMPORTANCE Antibiotics were originally defined as chemical compounds produced by a microbe that inhibits the growth of other microbes. However, an unexplained effect of this is that a low concentration of antibiotics, such as those below the minimum inhibitory concentration, can positively affect microbial growth and metabolism. The secondary metabolic activation of streptomycetes in the presence of the translation-inhibiting antibiotic lincomycin illustrates the concentration-dependent positive effect of the antibiotic. The significance of this study is that the phenomenological interpretation of the molecular mechanism of the concentration-dependent positive effect of lincomycin in Streptomyces coelicolor A3(2) has provided novel insight into the possible role of antibiotics in making their target molecules stable and active with the assistance of various related factors that benefit their function. Further exploration of this idea would lead to an essential understanding of antibiotics, including why actinomycetes make them and their role in nature.

Comparison of neoadjuvant and adjuvant chemotherapy for upper tract urothelial carcinoma in real-world practice: a multicenter retrospective study.

BACKGROUND: Multiple studies have demonstrated the effectiveness of neoadjuvant chemotherapy and adjuvant chemotherapy in patients with upper tract urothelial carcinoma compared with surgery alone. However, no clinical trial has established the superiority of neoadjuvant chemotherapy or adjuvant chemotherapy in terms of perioperative outcomes. METHODS: We conducted a retrospective analysis encompassing 164 upper tract urothelial carcinoma patients who underwent radical nephroureterectomy and received perioperative chemotherapy. Of these patients, 65 (39.6%) and 99 (60.4%) received neoadjuvant chemotherapy and adjuvant chemotherapy, respectively. Recurrence-free survival and cancer-specific survival were computed using the Kaplan-Meier method. Additionally, we conducted Cox regression analyses to evaluate the risk factors for recurrence-free survival and cancer-specific survival. RESULTS: Pathological downstaging was seen in 37% of the neoadjuvant chemotherapy group. However, no pathological complete response was observed in this cohort. The Kaplan-Meier curves demonstrated significantly lower recurrence-free survival and cancer-specific survival in patients who received adjuvant chemotherapy. Multivariate Cox regression analysis revealed patients treated with adjuvant chemotherapy exhibited a marked association with inferior recurrence-free survival and cancer-specific survival. CONCLUSION: Our study has suggested that neoadjuvant chemotherapy would be more effective in high-risk upper tract urothelial carcinoma patients compared with adjuvant chemotherapy.

Comparison of outcomes in high-risk prostate cancer patients treated with low-/high-dose-rate brachytherapy plus external beam radiotherapy.

BACKGROUND: Although brachytherapy is a standard treatment option for patients with high-risk prostate cancer, only a few studies have compared low-dose-rate brachytherapy (LDR-BT) and high-dose-rate brachytherapy (HDR-BT). We applied propensity score-based inverse probability treatment weighting (IPTW) to compare oncological outcomes for LDR-BT and HDR-BT. METHODS: We retrospectively assessed prognosis in 392 patients with high-risk localized prostate cancer who had undergone brachytherapy plus external beam radiation. IPTW was applied to adjust the Kaplan-Meier survival analyses and Cox proportional hazards regression analyses, with the goal of minimizing bias from patient background. RESULTS: The IPTW-adjusted Kaplan-Meier survival analyses showed no statistically significant differences for time to biochemical recurrence, clinical progression, castration-resistant prostate cancer, or death from any cause. The IPTW-adjusted Cox regression analyses also showed that the modality of brachytherapy was not an independent factor in these oncological outcomes. Notably, the two groups differed regarding complications; LDR-BT was associated with a higher rate of acute grade ≥ 2 GU toxicity, and late grade 3 toxicity was noted only in HDR-BT. CONCLUSION: Our analysis of long-term outcomes in patients with high-risk localized prostate cancer shows no significant differences in oncological outcomes between LDR-BT and HDR-BT, but some differences in toxicity, and offers patients and clinicians useful information in deciding management strategies for high-risk localized prostate cancer.

The prognostic significance of the clinical T stage and Grade Group in patients with locally advanced prostate cancer treated via high-dose-rate brachytherapy and external beam radiation.

BACKGROUND: Although the optimal management of locally advanced prostate cancer (PCa) remains unclear, local definitive therapy, thus combined radiotherapy and androgen deprivation, is one option. We evaluated the long-term outcomes of patients with locally advanced PCa who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiation therapy (EBRT). METHODS: We retrospectively analyzed 173 patients with locally advanced PCa (cT3a-4N0-1M0) who underwent HDR-BT and EBRT. We employed Cox's proportional hazards models to identify pre-treatment predictors of oncological outcomes. Treatment outcomes (biochemical recurrence-free survival [BCRFS], clinical progression-free survival [CPFS], and castration-resistant prostate cancer-free survival [CRPCFS] were compared according to the combination of the pre-treatment predictors. RESULTS: The 5-year BCRFS, CPFS, and CRPCFS rates were 78.5, 91.7, and 94.4% respectively; there were two PCa deaths. Multivariate analysis revealed that the clinical T stage (cT3b and cT4) and Grade Group (GG) 5 status were independent risk factors for poor BCRFS, CPFS, and CRPCFS. In the GG ≤ 4 group, the Kaplan-Meier curves for BCRFS, CPFS, and CRPCFS revealed excellent outcomes. However, in the GG5 group, patients with cT3b and cT4 PCa evidenced significantly poorer oncological outcomes than those with cT3a PCa. CONCLUSION: The clinical T stage and GG status were significantly prognostic of oncological outcomes in patients with locally advanced PCa. In patients of GG ≤ 4 PCa, HDR-BT was effective even in patients with cT3b or cT4 PCa. However, in patients with GG5 PCa, careful monitoring is essential, particularly of patients with cT3b or cT4 PCa.

Clinical characteristics of secondary bladder cancer developing after low-/high-dose-rate brachytherapy to treat localized prostate cancer.

BACKGROUND: To explore correlations between the clinical attributes of secondary bladder cancer and brachytherapy, we retrospectively reviewed our institutional database on patients with localized prostate cancer who underwent low-dose-rate brachytherapy (LDR-BT) or high-dose-rate brachytherapy (HDR-BT) with or without external beam radiation therapy (EBRT) or radical prostatectomy (RP). METHODS: From October 2003 to December 2014, 2551 patients with localized prostate cancer were treated at our institution. Of these, data on 2163 were available (LDR-BT alone: n = 953; LDR-TB with EBRT: n = 181; HDR-BT with EBRT: n = 283; RP without EBRT: n = 746). The times of secondary bladder cancer development subsequent to radical treatment, and their clinical characteristics, were studied. RESULTS: Age-adjusted Cox's regression analyses indicated that brachytherapy did not significantly impact the incidence of secondary bladder cancer. However, the pathological characteristics of such cancer differed between patients treated via brachytherapy and RP without EBRT; invasive bladder cancer was more common in such patients. CONCLUSION: The risk for secondary bladder cancer was not significantly increased after brachytherapy compared to non-irradiation therapy. However, brachytherapy patients exhibited a higher incidence of invasive bladder cancer. Therefore, meticulous follow-up is crucial for early detection and treatment of bladder cancer in such patients.

Patients with PSA below 0.2 ng/mL at 8 years post high-dose-rate brachytherapy have an extremely low risk of subsequent recurrence.

OBJECTIVES: We have analyzed the long-term follow-up data of patients with prostate cancer (PCa) who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT). The objective was to determine the optimal time for cessation of PSA monitoring after HDR-BT. METHODS: We included 309 patients with clinical stage T1c-T4 N0-1 M0 PCa who received HDR-BT and EBRT combined with long-term ADT between 2005 and 2018. We stratified the patients based on their prostate-specific antigen (PSA) levels and identified the factors associated with biochemical recurrence (BCR) and clinical progression (CP). RESULTS: The median follow-up duration was 98 months (range: 31-207 months). Among the 306 patients, 76 developed BCR and 47 developed CP subsequently. We found that the PSA levels at 3, 5, and 8 years significantly correlated with the oncological outcomes of brachytherapy. No patient with a PSA level ≤ 0.2 ng/mL at 8 years later developed BCR or CP. CONCLUSION: Our long-term data suggest that in the presence of a PSA level ≤ 0.2 ng/mL at 8 years later, PSA monitoring may be safely discontinued due to the extremely low risk of subsequent oncological events. The data presented in this study will assist clinicians in determining the optimal management strategy for patients with PCa following HDR-BT and EBRT combined with long-term ADT.

The chemical compound bubblin induces stomatal mispatterning in Arabidopsis by disrupting the intrinsic polarity of stomatal lineage cells.

Stem cell polarization is a crucial step in asymmetric cell division, which is a universal system for generating cellular diversity in multicellular organisms. Several conventional genetics studies have attempted to elucidate the mechanisms underlying cell polarization in plants, but it remains largely unknown. In plants, stomata, which are valves for gas exchange, are generated through several rounds of asymmetric divisions. In this study, we identified and characterized a chemical compound that affects stomatal stem cell polarity. High-throughput screening for bioactive molecules identified a pyridine-thiazole derivative, named bubblin, which induced stomatal clustering in Arabidopsis epidermis. Bubblin perturbed stomatal asymmetric division, resulting in the generation of two identical daughter cells. Both cells continued to express the stomatal fate determinant SPEECHLESS, and then differentiated into mispatterned stomata. Bubblin-treated cells had a defect in the polarized localization of BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL), which is required for asymmetric cell fate determination. Our results suggest that bubblin induces stomatal lineage cells to divide without BASL-dependent pre-mitotic establishment of polarity. Bubblin is a potentially valuable tool for investigating cell polarity establishment in stomatal asymmetric division.

A putative mechanism underlying secondary metabolite overproduction by Streptomyces strains with a 23S rRNA mutation conferring erythromycin resistance.

Mutations in rrn encoding ribosomal RNA (rRNA) and rRNA modification often confer resistance to ribosome-targeting antibiotics by altering the site of their interaction with the small (30S) and large (50S) subunits of the bacterial ribosome. The highly conserved central loop of domain V of 23S rRNA (nucleotides 2042-2628 in Escherichia coli; the exact position varies by species) of the 50S subunit, which is implicated in peptidyl transferase activity, is known to be important in macrolide interactions and resistance. In this study, we identified an A2302T mutation in the rrnA-23S rRNA gene and an A2281G mutation in the rrnC-23S rRNA gene that were responsible for resistance to erythromycin in the model actinomycete Streptomyces coelicolor A3(2) and its close relative Streptomyces lividans 66, respectively. Interestingly, genetic and phenotypic characterization of the erythromycin-resistant mutants indicated a possibility that under coexistence of the 23S rRNA mutation and mutations in other genes, S. coelicolor A3(2) and S. lividans 66 can produce abundant amounts of the pigmented antibiotics actinorhodin and undecylprodigiosin depending on the combinations of mutations. Herein, we report the unique phenomenon occurring by unexpected characteristics of the 23S rRNA mutations that can affect the emergence of additional mutations probably with an upswing in spontaneous mutations and enrichment in their variations in Streptomyces strains. Further, we discuss a putative mechanism underlying secondary metabolite overproduction by Streptomyces strains with a 23S rRNA mutation conferring erythromycin resistance.