The Chitinolytic Activities of Streptomyces sp. TH-11

Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by β-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy

Genotoxic Klebsiella pneumoniae in Taiwan

Colibactin is a nonribosomal peptide-polyketide synthesized by multi-enzyme complexes encoded by the pks gene cluster. Colibactin-producing Escherichia coli have been demonstrated to induce host DNA damage and promote colorectal cancer (CRC) development. In Taiwan, the occurrence of pyogenic liver abscess (PLA) has been suggested to correlate with an increasing risk of CRC, and Klebsiella pneumoniae is the predominant PLA pathogen in Taiwan

Prevalence of BRAF and NRAS mutations in cutaneous melanoma patients in Taiwan

BRAF and NRAS mutations have been described in melanomas among Caucasians and some Asian populations. However, few large-scale studies have investigated the status and clinical significance of BRAF and NRAS mutations in a Taiwanese population. Methods: Melanoma samples (n = 119) were analyzed for mutations in exons 11 and 15 of the BRAF gene, and in exons 1 and 2 of the NRAS gene. The samples were studied in genomic DNA, using polymerase chain reaction amplification and Sanger sequencing. Mutations of the BRAF and NRAS genes were then correlated with clinicopathological features and patients' prognosis. Results: The incidence of somatic mutations within the BRAF and NRAS genes was 14.3% (17/119 patients) and 10.1% (12/119 patients), respectively. Among the 17 patients with BRAF mutations, 15 (88.2%) had V600E mutations. BRAF mutation was frequently detected in younger patients (p = 0.0035), in thin melanomas (p = 0.0181), and in melanomas with less ulceration (p = 0.0089). NRAS mutation was more often seen in patients with lymph node metastasis (p = 0.0332). Both BRAF and NRAS mutations were not significantly correlated with overall survival and disease-free survival. Conclusion: As BRAF and NRAS mutations are rare in Taiwan, BRAF- or NRAS-targeted therapies may be effective only for selected Taiwanese melanoma patients

Interference of DNAJB6/MRJ Isoform Switch by Morpholino Inhibits Replication of HIV-1 and RSV

The molecular chaperon MRJ (DNAJB6) exhibits two splice isoforms that have different roles in human viral infection, but the regulatory mechanism of MRJ isoform expression is yet unclear. In this study, we show that reduction of the polyadenylation factor CstF64 was correlated with the increase of the MRJ large isoform (MRJ-L) in human macrophages and elucidate the mechanism underlying CstF64-modulated MRJ isoform expression. Moreover, we exploited an antisense strategy targeting MRJ-L for virus replication. A morpholino oligonucleotide complementary to the 5′ splice site of MRJ intron 8 downregulated MRJ-L expression and suppressed the replication of not only HIV-1 but also respiratory syncytial virus (RSV). We demonstrated that downregulation of the MRJ-L level reduced HIV-1 replication as well as the subgenomic mRNA and viral production of RSV. The present findings that two human health-threatening viruses take advantage of MRJ-L for infection suggest MRJ-L as a potential target for broad-spectrum antiviral strategy. Keywords: MRJ, DNAJB6, splicing, polyadenylation, CstF64, RSV, HIV-

Fever, eosinophilia, and abnormal liver function are early signs suggestive of DRESS: A comparative study between DRESS and MPE

Background/Objective: There is a rising awareness of drug reaction with eosinophilia and systemic symptoms (DRESS) due to its possible morbidity and mortality. Early diagnosis of DRESS is crucial for administering timely treatment; however, prompt diagnosis based on its early presentation can be quite problematic due to its clinical resemblance to common maculopapular eruptions (MPE). Methods: A retrospective cohort study of patient data from September 2010 to June 2016 was conducted to compare the clinical presentations of DRESS and MPE validated by the RegiSCAR scoring system. The demographic data, clinical presentations, and histopathological patterns were reviewed. Results: Fifty-eight patients with DRESS and 29 patients with MPE were included. The mean age at diagnosis of DRESS was 47 years (range: 2–82 years), and female patients predominated by a ratio of 2.2:1. The three most common culprit medications for DRESS were allopurinol, sulfasalazine, and trimethoprim/sulfamethoxazole. The most significant differences between the DRESS and MPE groups were the presence of fever, peripheral blood eosinophilia and atypical lymphocytosis, characteristic skin lesions, abnormal liver functions, and prolonged resolution of skin lesions for more than 15 days in the DRESS patients. The most common histologic features in the DRESS patients were coexistent eczematous, interface dermatitis, and vascular damage patterns, or interface dermatitis alone. The concurrence of fever, peripheral blood eosinophilia, and abnormal liver function within three days of visiting a medical facility were more common in cases of DRESS than of MPE (24.1% vs. 0%, P = 0.004). Conclusion: Although DRESS and MPE look similar, especially in the early stage of DRESS, the concurrence of fever, peripheral blood eosinophilia, and abnormal liver functions within three days of visiting a medical facility might aid in the early diagnosis of DRESS

Modified biweekly oxaliplatin and capecitabine for advanced gastric cancer: A retrospective analysis from a medical center

Background: We modified 3-week XELOX regimen with oxaliplatin to 85 mg/m 2 on Day 1 and capecitabine 1000 mg/m 2 BID for 10 days every 14 days to be more practical in clinical practice for advanced gastric cancer. The aim of this retrospective analysis is to evaluate the safety profile and efficacy of the modified oxaliplatin plus capecitabine (XELOX) regimen as the first-line treatment for patients with advanced gastric cancer in a medical center in Taiwan. Methods: From March 2009 to December 2010, among the 614 patients diagnosed with gastric cancer in a medical center, 49 patients with unresectable advanced or metastatic gastric adenocarcinoma were treated with oxaliplatin (85 mg/m 2 ) on Day 1 and capecitabine (1000 mg/m 2 BID) for 10 days every 2 weeks (mXELOX). CT scan was performed for tumor response evaluation. Clinical outcome and adverse events after mXELOX treatment were analyzed retrospectively. Results: A total of 354 mXELOX sessions (median: 6) were administered in 49 patients. The overall tumor response rate was 39.1% among 46 evaluated patients: three complete response (6.5%) and 15 partial response (32.6%). Seven patients had stable disease (15.2%) and 21 (45.7%) patients had progressive disease. The median progression-free survival and median overall survival were 4.37 months and 12.26 months, respectively. The most common grade III/IV hematologic toxicity was anemia (10.2%), and non-hematologic toxicity effects were numbness (8.2%), hand-foot syndrome (10.2%), diarrhea (6.1%), thrombocytopenia (6.1%), and abdominal pain (6.1%). Conclusion: This modified biweekly oxaliplatin and capecitabine combination chemotherapy is practical and effective for unresectable advanced or metastatic gastric cancer in our daily practice

The <i>pks</i> colibactin gene cluster (GM1) in KPHPI208 and the <i>pks</i> colibactin gene cluster in the <i>E. coli</i> IHE3034 genome.

<p>The regions spanning the genes responsible for colibactin production were depicted as arrows according to the directions of transcription. The <i>attO</i> sites in the left were marked by solid triangles. The VNTR locus between <i>clbR</i> and <i>clbB</i> was marked by empty triangles. The 53-kb regions indicated by dotted lines are ∼100% identical. The locations of the four PCR amplicons in studying the prevalence of the colibactin genes among <i>K. pneumoniae</i> clinical isolates were marked. The 768-bp region spanning the <i>clbA</i> gene, which was deleted in <i>ΔclbA</i> strain, was indicated.</p

<i>K. pneumoniae</i> 1084 induced colibactin-related DSBs <i>in vitro</i>.

<p>BNL cells were left uninfected (A) or were infected with <i>K. pneumoniae</i> 1084 (B), Δ<i>clbA</i> (C), or with Δ<i>clbA</i> complemented with <i>clbA</i> coding plasmid pYC502 (D) at an MOI of 100. After 4 h infection, the cells were washed, co-cultured with gentamycin (100 µg/ml), and were examined by confocal microscopy for DNA (blue, stained with Hoechst 33342), for membrane glycoproteins (red, stained with ConA), and for γH2AX (green, recognized by Alexa488-anti-γH2AX antibodies) (scale bar, 20 µm). (E) Quantification of γH2AX-positive cells. Error bars represent SEs from three experiments. (F) Western blot analyses of γH2AX or H3 in BNL cells recovered at 2, 4, and 6 h after a 4 h transient infection with <i>K. pneumoniae</i> 1084 (lanes 1–3), Δ<i>clbA</i> (lanes 4–6), or with Δ<i>clbA</i> complemented with <i>clbA</i>-coding plasmid pYC502 (lanes 7–9). (G) Western blot analyses of γH2AX and H3 in uninfected BNL cells harvested from serum recovery for 2, 4, 6, 24, 48, and 72 h. (H) Clonogenic assays. BNL cells were uninfected (Control) or transiently infected with <i>K. pneumoniae</i> 1084, Δ<i>clbA</i>, or with Δ<i>clbA</i>-pYC502 for 4 hours. Colonies formed after 14-day incubation stained with 0.5% of crystal violet. A representative image is presented. (I) Quantification of colony formation. Error bars represents SEMs from three experiments. An asterisk (*) represents a significant increase in the <i>K. pneumoniae</i>-infected group in comparison with the uninfected control by the Student's <i>t</i> test (two-tailed; <i>P</i><0.05).</p