Wen-Long Cho - Academia.edu (original) (raw)

Papers by Wen-Long Cho

Journal of Biological Chemistry, 1992

The Journal of general virology, Jan 19, 2016

Increasing evidence suggests that human cytomegalovirus (HCMV) plays an oncomodulatory role in hu... more Increasing evidence suggests that human cytomegalovirus (HCMV) plays an oncomodulatory role in human cancers. In colorectal cancer (CRC), presence of HCMV in tumors has been associated with a poor outcome in elderly patients. This study aimed to investigate the association between HCMV and the outcome of non-elderly patients with CRC. In tumor samples, HCMV DNA was detected by PCR. Viral transcript and protein were detected by in situ hybridization (ISH) and immunohistochemical staining (IHC), respectively. Clinical, pathological, and survival data were compared between patients with HCMV-positive and HCMV-negative tumors. Quantitative reverse-transcription PCR (qRT-PCR) was used to analyse the expression levels of cellular signals related to CRC progression and metastasis. Among 89 CRC non-elderly patients aged <65 years, HCMV was detected in 31 (34.8%) tumor samples by PCR. By ISH and IHC, viral transcript and protein specifically localized to the cytoplasm of neoplastic mucosa...

Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi, 2009

Acinetobacter baumannii isolates containing class 1 integrons belong to different clones, but onl... more Acinetobacter baumannii isolates containing class 1 integrons belong to different clones, but only a few strains are successful at causing infection. This study was conducted to compare the characteristics among these clones with different epidemicity. Eighty eight bacteremic isolates of A. baumannii were collected in a medical center in Taiwan during a 3-year period. The gene cassettes and antibiotic susceptibilities of the bacterial isolates were delineated and the patients' characteristics were compared. Class 1 integrons were detected in 75 isolates (85.2%). Most of the isolates belonged to 2 major clones, but only 1 of the 2 clones caused outbreaks in several hospitals in Taiwan. Restriction analyses of variable regions of the integron revealed identical gene cassettes among isolates within the same clone. The cassette arrays of the 3 clones were aacA4, catB8, aadA1 (clone I, epidemic clone); dhfr XII, unknown open reading frame (orfF), aadA2 (clone II, endemic clone); and ...

Journal of Biological Chemistry, 1999

Proceedings of the National Academy of Sciences, 1991

We report a phenomenon previously unknown for oviparous animals; in Aedes aegypti mosquitoes a se... more We report a phenomenon previously unknown for oviparous animals; in Aedes aegypti mosquitoes a serine carboxypeptidase is synthesized extraovarially and then internalized by oocytes. The cDNA encoding mosquito vitellogenic carboxypeptidase (VCP) was cloned and sequenced. The VCP cDNA hybridizes to a 1.5-kilobase mRNA present only in the fat body of vitellogenic females. The deduced amino acid sequence of VCP shares significant homology with members of the serine carboxypeptidase family. Binding assays using a serine protease inhibitor, [3H]diisopropyl fluorophosphate, showed that VCP is activated in eggs at the onset of embryonic development. Activation of VCP is associated with the reduction in its size from 53 kDa (inactive proenzyme) to 48 kDa (active enzyme). The active, 48-kDa, form of VCP is maximally present at the middle of embryonic development and disappears by the end.

Nephrology Dialysis Transplantation, 2007

Journal of Virological Methods, 2008

Studies of the human cytomegalovirus (HCMV) glycoprotein N (gpUL73-gN) showed that genotypic vari... more Studies of the human cytomegalovirus (HCMV) glycoprotein N (gpUL73-gN) showed that genotypic variations exist in different geographic areas, with gN-2 unidentified in Chinese population. The purpose of this study was to determine the HCMV gN variants in the Chinese population of Taiwan. Primers were designed and a polymerase chain reaction (PCR) was carried out on the UL73 gene. The PCR products were subjected to restriction fragment length polymorphism (RFLP) analysis. The same PCR-RFLP assay was repeated using primers published previously to demonstrate the influence of primer design. Of the 48 clinical HCMV isolates, 33 were positive for PCR products by both primer sets. Fifteen were positive only by the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;in-house&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; PCR. The distribution of gN-1, gN-2, gN-3, and gN-4 by RFLP analysis was 14:11:7:17, with one isolate positive for both gN-1 and gN-2. The published primers detected the four genotypes with the number of 14:0:2:17. The under-representation of gN-2 and gN-3 by the method published previously may be due to inappropriate primer design when re-examining the sequences. On the basis of the results of this study, gN-2 is not the rarest gN genotype in the Chinese population of Taiwan. The design of primers used for PCR-RFLP genotyping may have a great influence on the frequency distribution of HCMV genomic variants.

Journal of Microbiology, Immunology and Infection, 2012

Background and Purpose: To investigate the clinical and molecular epidemiology of the imipenem-re... more Background and Purpose: To investigate the clinical and molecular epidemiology of the imipenem-resistant Acinetobacter calcoaceticuseAcinetobacter baumannii (IRAcb) complex during an outbreak in an intensive care unit (ICU). Methods: Forty-six clinical and 11 environmental isolates of the IRAcb complex were collected from the ICU of Taipei Veterans General Hospital, Taiwan between December 2003 and March 2004. These isolates were genotyped using pulsed-field gel electrophoresis (PFGE). Carbapenemase genes and their associated genetic structures were analyzed using PCR. Clinical data obtained from the patients were also reviewed and analyzed. Results: The isolates were identified at the genomic species level as A. baumannii (42 clinical and five environmental isolates) and Acinetobacter genomic species 13TU (four clinical and six environmental isolates). Both species were comprised of two pulsotypes, but those of A. baumannii were closely related (83% similar). IS1008-DISAba3-bla OXA-58-like and ISAba1-bla OXA-51-like were identified in 22 and 21 clinical isolates of A. baumannii, respectively (one isolate contained both). The ISAba3-bracketed bla OXA-58-like gene was detected in all isolates of Acinetobacter genomic species 13TU. Patient transfers between different sections of the ICU were important factors that contributed to the spread of the two pulsotypes of A. baumannii. However, among the A. baumannii isolates identified, only those carrying IS1008-DISAba3-bla OXA-58-like could be

Journal of Clinical Microbiology, 2008

There are no previous reports of human infection due to Acinetobacter baylyi . In this study, we ... more There are no previous reports of human infection due to Acinetobacter baylyi . In this study, we report on six patients with bacteremia due to A. baylyi , based on analysis of the 16S-23S rRNA intergenic spacer and the 16S rRNA gene. All six patients had multiple underlying diseases. The infection was nosocomially acquired in five patients. The six clinical isolates had similar ribopatterns, suggesting a clonal relationship. Compared to the reference strain, the clinical isolates were more resistant to antimicrobial agents, especially beta-lactam antibiotics. In three of the isolates, they may have undetermined plasmid mediated class C type beta-lactamases because of the positive results in a double-disk synergy test using 3-aminophenylboronic acid. Two of the clinical isolates retained a level of natural transformability similar to that of the reference strain. None of the patients died, although only three of them received appropriate antimicrobial therapy. This study demonstrates...

Journal of Biomedical Science, 1998

Protein kinases play an important role in the signaling pathway of growth factors in most of the ... more Protein kinases play an important role in the signaling pathway of growth factors in most of the higher organisms. During the study of protein kinase profiles of mosquitoes using RT-PCR and degenerate primers for consensus catalytic domain motifs to amplify protein kinase genes, we have noticed that a novel mosquito kinase, AaPK-38, shares a stretch of amino acids identical to the corresponding domain in Tousled gene of Arabidopsis thaliana that is required for leaf and flower development. A 2.1-kb cDNA encoding human HsHPK gene, which is a homolog of AaPK-38, was isolated from human testis cDNA library. This cDNA contains an open reading frame of 563 amino acids, with a complete kinase domain in its carboxyl terminus. The expressed Flag-tagged HsHPK was shown to have kinase activity based on in vitro autophosphorylation. Northern blot analysis revealed that human HsHPK mRNA is most abundant in testes, much less in heart and skeletal muscle and almost undetectable in liver and lung. Finally, we found that the expression of HsHPK in 4 out of 6 human hepatoma tissues is much higher than that in the adjacent normal counterpart. This result suggests HsHPK may play a role in the development of human hepatoma.

Journal of Biological Chemistry, 2012

Background: Previous studies suggest that the C. neoformans hyaluronic acid and host CD44 interac... more Background: Previous studies suggest that the C. neoformans hyaluronic acid and host CD44 interaction could be the initial step of brain invasion. Results: CD44 knockout mouse model verified the pathophysiology of C. neoformans brain invasion. Conclusion: The CD44 receptor on membrane lipid rafts is involved. Significance: The mechanism of invasion and a potential clinical intervention strategy were identified. Cryptococcus neoformans is a pathogenic yeast that can invade the brain and cause meningoencephalitis. Our previous in vitro studies suggested that the interaction between C. neoformans hyaluronic acid and human brain endothelial CD44 could be the initial step of brain invasion. In this report, we used a CD44 knockout (KO or CD44 ؊/؊) mouse model to explore the importance of CD44 in C. neoformans brain invasion. Our results showed that C. neoformans-infected CD44 KO mice survived longer than the infected wild-type mice. Consistent with our in vitro results, the brain and cerebrospinal fluid fungal burden was reduced in CD44-deficient mice. Histopathological studies showed smaller and fewer cystic lesions in the brains of CD44 KO mice. Interestingly, the cystic lesions contained C. neoformans cells embedded within their polysaccharide capsule and were surrounded by host glial cells. We also found that a secondary hyaluronic acid receptor, RHAMM (receptor of hyaluronanmediated motility), was present in the CD44 KO mice. Importantly, our studies demonstrated an in vivo blocking effect of simvastatin. These results suggest that the CD44 and RHAMM receptors function on membrane lipid rafts during invasion and that simvastatin may have a potential therapeutic role in C. neoformans infections of the brain. Cryptococcus neoformans invades the brain and causes meningoencephalitis, primarily in immunocompromised patients and sporadically in normal hosts. It is the most common fungal infection of the central nervous system and is one of the major causes of death in AIDS patients (1, 2). C. neoformans is encompassed by a polysaccharide capsule composed mainly of glucuronoxylomannan (GXM) 3 (3); this capsule is known to be the major virulence factor of this yeast (4-6). As such, the role and biogenesis of the capsule has become an area of focus for research in this pathogen (7). Previously, we characterized the C. neoformans gene CPS1 (capsule polysaccharide synthase 1) (8). Deletion of CPS1 from C. neoformans cells causes alterations in the ultrastructure between the cell wall and capsule, and the deletant shows a reduced ability to associate with human brain microvascular endothelial cells (HBMEC). Polysaccharide hyaluronic acid (HA; also known as hyaluronan) can be detected in the wild-type C. neoformans strain but not in cps1⌬ cells. Testing of C. neoformans strains with different concentrations of HA demonstrated that the ability of yeast to bind to HBMEC is proportional to their HA content. Subsequent analysis indicated that the CPS1 gene encodes an HA synthase (9). Taken together, these findings indicate that the C. neoformans CPS1 gene product, HA, plays a role as an adhesion molecule during interaction with endothelial cells. Several HA-binding proteins (or HA receptors) localized in the membranes, such as CD44, RHAMM, Ivd4, LEC receptor, and others, have been identified in different cell types (10, 11). The most common HA receptor is CD44, which plays different roles in different cell types. As CD44 is a major membrane HA receptor, it is conceivable that C. neoformans HA directly engages with the HBMEC CD44 as a part of its invasion mechanism. Indeed, we have demonstrated that C. neoformans HA interacts with CD44 on HBMEC, a primary receptor in C. neoformans infection (12). For example, an anti-CD44 neutralizing antibody treatment significantly reduces C. neoformans association with HBMEC. Association of C. neoformans with HBMEC is also found to be considerably impaired either in CD44 knockdown HBMEC or HA-deficient C. neoformans

European Journal of …, 1995

... Diptera: Culicidae) Kirk W. DEITSCH, Nhal DITTMER, Marianna Z. KAPITSKAYA, Jknu-Shong CHEN, W... more ... Diptera: Culicidae) Kirk W. DEITSCH, Nhal DITTMER, Marianna Z. KAPITSKAYA, Jknu-Shong CHEN, Wen-Long CHO* and Alexander S. RAIKHEL ... A: A 16 bp imperfect palin-drome found repeated four times with similarity to the consensus ecdysteroid response element. ...

Biomarkers, 2014

Investigate the latent cytomegalovirus (CMV) infection as a biomarker of oxidative stress and ath... more Investigate the latent cytomegalovirus (CMV) infection as a biomarker of oxidative stress and atherosclerosis. Latent CMV infection was diagnosed in healthy individuals with PCR-evidence of CMV DNA in peripheral leucocytes. Oxidative stress and atherosclerosis were measured by mitochondrial DNA oxidative damage index (mtDNA(ΔCT)) and intima media thickness (IMT). The CMV DNA positive subjects had a higher mean mtDNA(ΔCT) and greater IMT than subjects in the control group. Presence of CMV DNA in leucocytes, as a marker of latent CMV infection, was associated with increased levels of oxidative stress and subclinical atherosclerosis in healthy adults.

Biology of Reproduction, 2002

Propylthiouracil (PTU) is a thioamide drug used clinically to inhibit thyroid hormone production.... more Propylthiouracil (PTU) is a thioamide drug used clinically to inhibit thyroid hormone production. However, PTU is associated with some side effects in different organs. In the present study, the acute and direct effects of PTU on testosterone production in rat Leydig cells were investigated. Leydig cells were isolated from rat testes, and an investigation was performed on the effects of PTU on basal and evoked-testosterone release, the functions of steroidogenic enzymes, including protein expression of cytochrome P450 side-chain cleavage enzyme (P450 scc) and mRNA expression of the steroidogenic acute regulatory protein (StAR). Rat Leydig cells were challenged with hCG, forskolin, and 8-bromo-cAMP to stimulate testosterone release. PTU inhibited both basal and evoked-testosterone release. To study the effects of PTU on steroidogenesis, steroidogenic precursor-stimulated testosterone release was examined. PTU inhibited pregnenolone production (i.e., it diminished the function of P450 scc in Leydig cells). In addition to inhibiting hormone secretion, PTU also regulated steroidogenesis by diminishing mRNA expression of StAR. These results suggest that PTU acts directly on rat Leydig cells to diminish testosterone production by inhibiting P450 scc function and StAR expression.

Antimicrobial Agents and Chemotherapy, 2008

The oxacillinase gene was reported to confer limited resistance to carbapenem in Acinetobacter ba... more The oxacillinase gene was reported to confer limited resistance to carbapenem in Acinetobacter baumannii . In this study, we have demonstrated that an A. baumannii clinical isolate harboring a plasmid, pTVICU53, has 11,037 bp encoding 13 open reading frames. A bla OXA-58 gene with an upstream insertion of truncated IS Aba3 (ΔIS Aba3 ) and IS 1008 was found in this plasmid. ΔIS Aba3 and IS 1008 provided two independent promoters for the transcription control of the bla OXA-58 gene. The transformation of pTVICU53 or a shuttle vector bearing IS 1008 -ΔIS Aba3 - bla OXA-58 to different A. baumannii recipients can increase their MICs of carbapenem 64- to 256-fold. The deletion of promoters provided by IS 1008 resulted in dramatic decreases in bla OXA-58 transcription and a 32- to 64-fold reduction in the carbapenem MIC. These findings highlight that A. baumannii might develop carbapenem resistance with a single transformation step, taking up a plasmid containing a genetic construct with ...

Antimicrobial Agents and Chemotherapy, 2010

The contribution of the bla OXA-58 gene and its promoter to β-lactam resistance has not been vali... more The contribution of the bla OXA-58 gene and its promoter to β-lactam resistance has not been validated in Acinetobacter spp. other than Acinetobacter baumannii . We identified a multidrug-resistant (including carbapenem resistance) Acinetobacter genomic species 13TU in which bla OXA-58 was the only detected carbapenemase gene. The bla OXA-58 gene was plasmid located, flanked by IS Aba3 (downstream) and an IS Aba3- like element (upstream). An IS 1006 element was inserted into IS Aba3 -like (IS 1006 -ΔIS Aba3 -like) to generate a hybrid promoter for bla OXA-58 , with a −35 promoter located in IS 1006 and a −10 promoter in IS Aba3 -like. The reference strain of Acinetobacter genomic species 13TU, ATCC 17903, revealed higher MICs of amoxicillin, ticarcillin, and piperacillin and heteroresistance to imipenem and meropenem when it was transformed with a shuttle vector containing a fragment encompassing ΔIS Aba3 -like- bla OXA-58 , compared to the same host containing only bla OXA-58 . Whe...

The role of carbapenem-resistant Acinetobacter baumannii (CRAb) in polymicrobial infection remain... more The role of carbapenem-resistant Acinetobacter baumannii (CRAb) in polymicrobial infection remains elusive. Having observed the ability of CRAb to shelter other susceptible bacteria from carbapenem killing, we sought to determine the factors contributing to this sheltering effect by transforming different recombinant plasmids into recipient A. baumannii cells. The sheltering effects of CRAb were reproduced in recipient A. baumannii cells that highly expressed carbapenem-hydrolyzing class D ␤-lactamases (CHDLs) through their associated strong promoter. With the use of Western blot analysis and a bioassay, the highly expressed CHDLs were found to be extracellularly released and led to hydrolysis of carbapenem. The level of extracellular CHDLs increased after challenge with a higher concentration of CHDL substrates, such as carbapenem and ticarcillin. This increased CHDL may, in part, be attributed to cell lysis, as indicated by the presence of extracellular gyrase. In the planktonic condition, the sheltering effect for the cocultured susceptible bacteria might represent an indirect and passive effect of the CRAb self-defense mechanism, because coculture with the susceptible pathogen did not augment the amount of the extracellular CHDLs. Polymicrobial infection caused by CRAb and a susceptible counterpart exerted higher pathogenicity than monomicrobial infection caused by either pathogen alone in mice receiving carbapenem therapy. This study demonstrated that CHDL-producing CRAb appears to provide a sheltering effect for carbapenem-susceptible pathogens via the extracellular release of CHDLs and, by this mechanism, can enhance the pathogenesis of polymicrobial infection in the presence of carbapenem therapy.

Molecular Insect Science, 1990

The maturation of insect eggs requires the fat body production of large amounts of a protein, vit... more The maturation of insect eggs requires the fat body production of large amounts of a protein, vitellogenin (Vg), that is secreted into the hemolymph, selectively accumulated by the oocytes and stored in yolk bodies as crystalline vitellin (Vn). The coordination of activity in fat body and oocytes during vitellogenesis is achieved through a complex regulatory mechanism. The mosquito, Aedes aegypti, has proven to be a valuable organism in the study of vitellogenesis.

Proceedings of the National Academy of Sciences, 2000

Progress in molecular genetics makes possible the development of alternative disease control stra... more Progress in molecular genetics makes possible the development of alternative disease control strategies that target the competence of mosquitoes to transmit pathogens. We tested the regulatory region of the vitellogenin ( Vg ) gene of Aedes aegypti for its ability to express potential antipathogen factors in transgenic mosquitoes. Hermes -mediated transformation was used to integrate a 2.1-kb Vg -promoter fragment driving the expression of the Defensin A ( DefA ) coding region, one of the major insect immune factors. PCR amplification of genomic DNA and Southern blot analyses, carried out through the ninth generation, showed that the Vg-DefA transgene insertion was stable. The Vg-DefA transgene was strongly activated in the fat body by a blood meal. The mRNA levels reached a maximum at 24-h postblood meal, corresponding to the peak expression time of the endogenous Vg gene. High levels of transgenic defensin were accumulated in the hemolymph of bloodfed female mosquitoes, persisting...

Journal of Molecular Biology, 1994

The cDNA coding for vitellogenin of the mosquito Aedes aegypti was cloned and sequenced. An immun... more The cDNA coding for vitellogenin of the mosquito Aedes aegypti was cloned and sequenced. An immunological analysis of expressed deletions from the 5'-end of the vitellogenin cDNA clones using vitellogenin subunit-specific antibodies showed that the small vitellogenin subunit is located at the N terminus and the large one at the carboxy-portion of the pre-provitellogenin. The position of the cleavage between the vitellogenin subunits in the pre-provitellogenin was identified by locating the N terminus of the large subunit. The cleavage site has a consensus RXRR for the subtilisin-processing endoprotease. Mosquito vitellogenin is highly hydrophilic with 17 putative N-linked glycosylation sites and 13 potential tyrosine sulfation sites. In contrast to known invertebrate vitellogenins, mosquito vitellogenin contains three polyserine domains that are similar to those of phosvitins in vertebrate vitellogenins. These polyserine domains, originally presumed to be vertebrate-specific, have several phosphorylation consensus sites in their sequences. Unlike other known vitellogenins, mosquito vitellogenin is rich in aromatic amino acid residues, tyrosine and phenylalanine, and in this respect is similar to insect serum proteins, arylphorins. This similarity suggests that mosquito vitellogenin may supply aromatic amino acids to the cuticle of rapidly developing embryos.