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

Broad-Spectrum Resistance to Different Geographic Strains of Papaya ringspot virus in Coat Protein Gene Transgenic Papaya

Papaya ringspot virus (PRSV) is a major limiting factor for cultivation of papaya (Carica papaya) in tropical and subtropical areas throughout the world. Although the coat protein (CP) gene of PRSV has been transferred into papaya by particle bombardment and transgenic lines with high resistance to Hawaii strains have been obtained, they are susceptible to PRSV isolates outside of Hawaii. This strain-specific resistance limits the application of the transgenic lines in other areas of the world. In this investigation, the CP gene of a local strain isolated from Taiwan, designated PRSV YK, was transferred into papaya via Agro-bacterium-mediated transformation. A total of 45 putative transgenic lines were obtained and the presence of the transgene in papaya was confirmed by polymerase chain reaction amplification. When the plants of transgenic lines were challenged with PRSV YK by mechanical inoculation, they showed different levels of resistance ranging from delay of symptom development to complete immunity. Molecular analysis of nine selected lines that exhibited different levels of resistance revealed that the expression level of the transgene is negatively correlated with the degree of resistance, suggesting that the resistance is manifested by a RNA-mediated mechanism. The segregation analysis showed that the transgene in the immune line 18-0-9 has an inheritance of two dominant loci and the other four highly resistant lines have a single dominant locus. Seven selected lines were tested further for resistance to three PRSV heterologous strains that originated in Hawaii, Thailand, and Mexico. Six of the seven lines showed varying degrees of resistance to the heterologous strains, and one line, 19-0-1, was immune not only to the homologous YK strain but also to the three heterologous strains. Thus, these CP-transgenic papaya lines with broad-spectrum resistance have great potential for use in Taiwan and other geographic areas to control PRSV

Field Evaluation of Transgenic Papaya Lines Carrying the Coat Protein Gene of Papaya ringspot virus in Taiwan

Four transgenic papaya lines expressing the coat protein (CP) gene of Papaya ringspot virus (PRSV) were evaluated under field conditions for their reaction to PRSV infection and fruit production in 1996 to 1999. Plants were exposed to natural virus inoculation by aphids in two adjacent fields in four different plantings at the same sites. None of the transgenic lines showed severe symptoms of PRSV whereas control nontransgenic plants were 100% severely infected 3 to 5 months after planting. In the first and second trials, 20 to 30% of the transgenic plants showed mild symptoms consisting of confined mottling or chlorotic spots on leaves. The number of transgenic plants with mild symptoms fluctuated according to the season and weather conditions, with a tendency to increase in the winter or rainy season and decrease in the summer. Also, the incidence of the mild symptoms in the third trial increased significantly due to infection by root rot fungi during the rainy season. Interestingly, there was no apparent adverse effect on fruit yield and quality in transgenic plants with mild symptoms. In the first and second experiments, transgenic lines yielded 10.8 to 11.6 and 54.3 to 56.7 times more marketable fruit, respectively, than controls. All transgenic plants produced fruit of marketable quality with no ringspots or distortion

Molecular Authentication of Dendrobium Species by Multiplex Polymerase Chain Reaction and Amplification Refractory Mutation System Analysis

The genus Dendrobium is important in traditional Chinese herbal medicine, and the precise identification of Dendrobium species is critical for the treatment and for pharmacological research. In the present study, a ribosomal DNA (rDNA) internal transcribed spacer (ITS) region-based analysis was used to ascertain the phylogenetic relationship among 20 Dendrobium species. The lengths of the ITS regions among the 20 species ranged from 636 to 653 bp, and the identities of the rDNA regions among the different species ranged from 75.7% to 99.1%. The results also showed that the ITS1 and ITS2 regions exhibit more variation than the 5.8S rDNA. A phylogenetic tree derived from the ITS sequence indicated that six medicinal Dendrobium species, of which five are common medicinal plants in the Taiwan market, were closely related and shared a common clade. Multiplex polymerase chain reaction (PCR) amplification was successfully performed to identify the six medicinal Dendrobium species, and amplification refractory mutation system (ARMS) PCR was used to distinguish D. tosaense specifically from the 19 other Dendrobium species. The established PCR-based (multiplex and ARMS) analyses can be used for the authentication of the raw materials of medicinal Dendrobium from other species

Development of transgenic watermelon resistant to Cucumber mosaic virus and Watermelon mosaic virus by using a single chimeric transgene construct

Watermelon, an important fruit crop worldwide, is prone to attack by several viruses that often results in destructive yield loss. To develop a transgenic watermelon resistant to multiple virus infection, a single chimeric transgene comprising a silencer DNA from the partial N gene of Watermelon silver mottle virus (WSMoV) fused to the partial coat protein (CP) gene sequences of Cucumber mosaic virus (CMV), Cucumber green mottle mosaic virus (CGMMV) and Watermelon mosaic virus (WMV) was constructed and transformed into watermelon (cv. Feeling) via Agrobacterium-mediated transformation. Single or multiple transgene copies randomly inserted into various locations in the genome were confirmed by Southern blot analysis. Transgenic watermelon R0 plants were individually challenged with CMV, CGMMV or WMV, or with a mixture of these three viruses for resistance evaluation. Two lines were identified to exhibit resistance to CMV, CGMMV, WMV individually, and a mixed inoculation of the three viruses. The R1 progeny of the two resistant R0 lines showed resistance to CMV and WMV, but not to CGMMV. Low level accumulation of transgene transcripts in resistant plants and small interfering (si) RNAs specific to CMV and WMV were readily detected in the resistant R1 plants by northern blot analysis, indicating that the resistance was established via RNA-mediated post-transcriptional gene silencing (PTGS). Loss of the CGMMV CP-transgene fragment in R1 progeny might be the reason for the failure to resistant CGMMV infection, as shown by the absence of a hybridization signal and no detectable siRNA specific to CGMMV in Southern and northern blot analyses. In summary, this study demonstrated that fusion of different viral CP gene fragments in transgenic watermelon contributed to multiple virus resistance via PTGS. The construct and resistant watermelon lines developed in this study could be used in a watermelon breeding program for resistance to multiple viruses

Assessment of acute kidney injury risk using a machine-learning guided generalized structural equation model: a cohort study

10.1186/s12882-021-02238-9BMC Nephrology2216

<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

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

RECOMBINANT PLASMID FOR PROVIDING PLANTS WITH RESISTANCE AGAINST PAPAYA LEAF-DISTORTION MOSAIC VIRUS AND USE THEREOF

本發明係一種用於提供植物抗木瓜畸葉嵌紋病毒性狀的的重組載體,其係包含一控制序列以及一與該控制序列可操作的連接的一木瓜畸葉嵌紋病毒(Papaya leaf-distortion mosaic virus,PLDMV)鞘蛋白基因(coat protein gene,CP gene)片段。本發明亦提供一種重組微生物。本發明亦提供一種使植物對病毒具有抗性的方法。本發明係提供植物對於木瓜畸葉嵌紋病毒之抗性,藉以使產生的基因轉殖植物(transgenic plant)具有較高的產業應用價値

RECOMBINANT PLASMID FOR PROVIDING PLANTS WITH RESISTANCE AGAINST PAPAYA RINGSPOT VIRUS AND PAPAYA LEAF-DISTORTION MOSAIC VIRUS AND USE THEREOF

本發明係一種用於提供植物抗雙重病毒之抗性的的重組載體,其係包含一控制序列以及一與該控制序列可操作的連接的重組基因,該重組基因係包括一木瓜輪點病毒(Papaya ringspot virus,PRSV)鞘蛋白基因片段以及一木瓜畸葉嵌紋病毒(Papaya leaf-distortion mosaic virus,PLDMV)鞘蛋白基因(coat protein gene,CP gene)片段。本發明亦提供一種衍生自該重組載體的重組微生物。本發明亦提供一種使植物對病毒具有抗性的方法。本發明係提供植物對於木瓜輪點病毒和木瓜畸葉嵌紋病毒兩者之抗性,藉以使產生的基因轉殖植物(transgenic plant)具有較高的產業應用價値