Clinical Implementation of Dual-Energy CT Technical for Hepatobiliary Imaging.

Dual-energy computed tomography (DECT) applies two energy spectra distributions to collect raw data based on traditional CT imaging. The application of hepatobiliary imaging, has the advantages of optimizing the scanning scheme, improving the imaging quality, highlighting the disease characterization, and increasing the detection rate of lesions. In order to summarize the clinical application value of DECT in hepatobiliary diseases, we searched the technical principles of DECT and its existing studies, case reports, and clinical guidelines in hepatobiliary imaging from 2010 to 2023 (especially in the past 5 years) through PubMed and CNKI, focusing on the clinical application of DECT in hepatobiliary diseases, including liver tumors, diffuse liver lesions, and biliary system lesions. The first part of this article briefly describes the basic concept and technical advantages of DECT. The following will be reviewed:the detection of lesions, diagnosis and differential diagnosis of lesions, hepatic steatosis, quantitative analysis of liver iron, and analyze the advantages and disadvantages of DECT in hepatobiliary imaging. Finally, the contents of this paper are summarized and the development prospect of DECT in hepatobiliary imaging is prospected.

Infant with reverse-transcription polymerase chain reaction confirmed COVID-19 and normal chest computed tomography: A case report.

BACKGROUND: Coronavirus disease-2019 (COVID-19) is a highly pathogenic respiratory disease that mainly affects adults and elderly patients. Yet, over the past three years, there were an increasing number of infected children; however, only a few cases of infants with reverse-transcription polymerase chain reaction (RT-PCR)-confirmed COVID-19 and chest computed tomography (CT) normal have been reported. Herein, we reported a single case of a patient (a 3-mo-old girl) with COVID-19, including her clinical and imaging findings. CASE SUMMARY: The patient with fever, diarrhea came to fever clinic. Her chest CT was normal. The patient was treated accordingly, the fever disappeared while diarrhea persisted, what's more, RT-PCR testing of nasopharyngeal swab showed positive results; thus, the patient was admitted to the pediatric department on the 5th day of onset. The child was given systematic treatment, and all her symptoms significantly improved. Consecutive RT-PCR tests were negative after examining the pharyngeal swabs but positive after analyzing anal swabs. She was discharged on the 31st day of hospitalization. CONCLUSION: This report provides useful references for treating infantile COVID-19 cases with diarrhea or other non-respiratory symptoms and normal chest CT scan. Given the persistent positive RT-PCR results of anal swabs, the possibility of fecal-oral transmission of COVID-19 should be considered.

The RpfB-Dependent Quorum Sensing Signal Turnover System Is Required for Adaptation and Virulence in Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, produces diffusible signal factor (DSF) family quorum sensing signals to regulate virulence. The biosynthesis and perception of DSF family signals require components of the rpf (regulation of pathogenicity factors) cluster. In this study, we report that RpfB plays an essential role in DSF family signal turnover in X. oryzae pv. oryzae PXO99A. The production of DSF family signals was boosted by deletion of the rpfB gene and was abolished by its overexpression. The RpfC/RpfG-mediated DSF signaling system negatively regulates rpfB expression via the global transcription regulator Clp, whose activity is reversible in the presence of cyclic diguanylate monophosphate. These findings indicate that the DSF family signal turnover system in PXO99A is generally consistent with that in Xanthomonas campestris pv. campestris. Moreover, this study has revealed several specific roles of RpfB in PXO99A. First, the rpfB deletion mutant produced high levels of DSF family signals but reduced extracellular polysaccharide production, extracellular amylase activity, and attenuated pathogenicity. Second, the rpfB/rpfC double-deletion mutant was partially deficient in xanthomonadin production. Taken together, the RpfB-dependent DSF family signal turnover system is a conserved and naturally presenting signal turnover system in Xanthomonas spp., which plays unique roles in X. oryzae pv. oryzae adaptation and pathogenesis.

AvrXa7-Xa7 mediated defense in rice can be suppressed by transcriptional activator-like effectors TAL6 and TAL11a from Xanthomonas oryzae pv. oryzicola.

The closely related plant pathogens Xanthomonas oryzae pv. oryzicola and X. oryzae pv. oryzae cause bacterial leaf streak (BLS) and bacterial leaf blight (BLB), respectively, in rice. Unlike X. oryzae pv. oryzae, endogenous avirulence-resistance (avr-R) gene interactions have not been identified in the X. oryzae pv. oryzicola-rice pathosystem, though both X. oryzae pv. oryzicola and X. oryzae pv. oryzae possess transcriptional activator-like effectors (TALE), which are known to modulate R or S genes in rice. In this report, avrXa7, avrXa10, and avrXa27 from X. oryzae pv. oryzae were transferred into YNB0-17 and RS105, hypovirulent and hypervirulent strains, respectively, of X. oryzae pv. oryzicola. When YNB0-17 containing avrXa7, avrXa10, or avrXa27 was inoculated to rice, hypersensitive responses (HR) were elicited in rice cultivars containing the R genes Xa7, Xa10, and Xa27, respectively. By contrast, RS105 expressing avrXa27 elicited an HR in a rice cultivar containing Xa27 but the expression of avrXa7 and avrXa10 in RS105 did not result in HR in rice cultivars containing Xa7 and Xa10, correspondingly. Southern blot analysis demonstrated that YNB0-17 possesses only approximately nine putative tale genes, whereas the hypervirulent RS105 contains at least 20. Although YNB0-17 contains an intact type III secretion system (T3SS), its genome is lacking the T3SS effector genes avrRxo1 and xopO, which are present in RS105. The introduction of avrRxo1 and xopO into YNB0-17 did not suppress avrXa7- or avrXa10-triggered immunity in rice. However, the transference of individual tale genes from RS105 into YNB0-17 led to the identification of tal6 and tal11a that suppressed avrXa7-Xa7-mediated defense. Thus, YNB0-17 may be a useful recipient for discovering such suppressors. This is the first report that co-evolutionally generated tale genes in X. oryzae pv. oryzicola suppress gene-for-gene defense against BLB, which may explain the lack of BLS-resistant cultivars.

Genetic diversity of transcriptional activator-like effector genes in Chinese isolates of Xanthomonas oryzae pv. oryzicola.

Xanthomonas oryzae pv. oryzicola causes bacterial leaf streak (BLS), a devastating disease of rice in Asia countries. X. oryzae pv. oryzicola utilizes repertoires of transcriptional activator-like effectors (TALEs) to manipulate host resistance or susceptibility; thus, TALEs can determine the outcome of BLS. In this report, we studied genetic diversity in putative tale genes of 65 X. oryzae pv. oryzicola strains that originated from nine provinces of southern China. Genomic DNAs from the 65 strains were digested with BamHI and hybridized with an internal fragment of avrXa3, a tale gene originating from the related pathogen, X. oryzae pv. oryzae, which causes bacterial leaf blight (BLB). Southern blot analysis indicated that the strains contained a variable number (9 to 22) of avrXa3-hybridizing fragments (e.g., putative tale genes). Based on the number and size of hybridizing bands, strains were classified into 14 genotypes (designated 1 to 14), and genotypes 3 and 10 represented 29.23 and 24.64% of the total, respectively. A high molecular weight BamHI fragment (HMWB; ≈6.0 kb) was present in 12 of the 14 genotypes, and sequence analysis of the HMWB revealed the presence of a C-terminally truncated tale, an insertion element related to IS1403, and genes encoding phosphoglycerate mutase and endonuclease V. Primers were developed from the 6.0-kb HMWB fragment and showed potential in genotyping X. oryzae pv. oryzicola strains by polymerase chain reaction. Virulence of X. oryzae pv. oryzicola strains was assessed on 23 rice cultivars containing different resistance genes for BLB. The X. oryzae pv. oryzicola strains could be grouped into 14 pathotypes (I to XIV), and the grouping of strains was almost identical to the categories determined by genotypic analysis. In general, strains containing higher numbers of putative tale genes were more virulent on rice than strains containing fewer tales. The results also indicate that there are no gene-for-gene relationships between the tested rice lines and X. oryzae pv. oryzicola strains. To our knowledge, this is the first description of genetic diversity of X. oryzae pv. oryzicola strains based on tale gene analysis.

Efficacy of Metarhizium anisopliae isolate MAX-2 from Shangri-la, China under desiccation stress.

BACKGROUND: Metarhizium anisopliae, a soil-borne entomopathogen found worldwide, is an interesting fungus for biological control. However, its efficacy in the fields is significantly affected by environmental conditions, particularly moisture. To overcome the weakness of Metarhizium and determine its isolates with antistress capacity, the efficacies of four M. anisopliae isolates, which were collected from arid regions of Yunnan Province in China during the dry season, were determined at different moisture levels, and the efficacy of the isolate MAX-2 from Shangri-la under desiccation stress was evaluated at low moisture level. RESULTS: M. anisopliae isolates MAX-2, MAC-6, MAL-1, and MAQ-28 showed gradient descent efficacies against sterile Tenebrio molitor larvae, and gradient descent capacities against desiccation with the decrease in moisture levels. The efficacy of MAX-2 showed no significant differences at 35% moisture level than those of the other isolates. However, significant differences were found at 8% to 30% moisture levels. The efficacies of all isolates decreased with the decrease in moisture levels. MAX-2 was relatively less affected by desiccation stress. Its efficacy was almost unaffected by the decrease at moisture levels > 25%, but slowly decreased at moisture levels < 25%. By contrast, the efficacies of other isolates rapidly decreased with the decrease in moisture levels. MAX-2 caused different infection characteristics on T. molitor larvae under desiccation stress and in wet microhabitat. Local black patches were found on the cuticles of the insects, and the cadavers dried without fungal growth under desiccation stress. However, dark black internodes and fungal growth were found after death of the insects in the wet microhabitat. CONCLUSIONS: MAX-2 showed significantly higher efficacy and superior antistress capacity than the other isolates under desiccation stress. The infection of sterile T. molitor larvae at low moisture level constituted a valid laboratory bioassay system in evaluating M. anisopliae efficacy under desiccation stress.

[Molecular identification and genetic diversity in Konnyaku's soft rot bacteria].

The soft rot bacteria Erwinia are an important pathogens of konnyaku and other ornamental plants. Thirty-three strains were isolated from soft-rotted konnyaku and other ornamental plants. According to the characteristics of pathogenicity and culture character on semi selective medium (crystal violet pectate, CVP), most of strains tested caused rotten symptom in tubers and stems of konnyaku, and characteristic deep cavities were formed on CVP. To amplify 16S-23S rDNA intergenic transcribed spacer( ITS) by PCR and electrophorese through agarose gel, most strains are clustered into two heterogeneous populations of Erwinia carotovora subsp. carotovora, E.c.c. and Erwinia chrysanthemi, E. ch.. Besides, several other strains could not be identified into species by ITS-PCR. The characteristic band patterns of E.c.c. and E.ch. could be clearly distinguished by repetitive element-polymerase chain reaction (rep-PCR,BOX and J3 primers). And the fingerprinting of E.c.c. stains were also different from each other. Dendrogram was generated from the data of primer BOX by using UPGMA analysis because the primer BOX was higher resolution than other primers (such as prime J3) for identifying the same intraspecies strains. Strains of E.c.c. were divided into five groups on the 0.1 level of linkage distance.