T3SS protein EsrC binds to the lacI-like operator of type 1 fimbrial operon to suppress adhesion of Edwardsiella piscicida.

Type 1 fimbria, the short hair-like appendage assembled on the bacterial surface, plays a pivotal role in adhesion and invasion in Edwardsiella piscicida. The type III secretion system (T3SS), another bacterial surface appendage, facilitates E. piscicida's replication in vivo by delivering effectors into host cells. Our previous research demonstrated that E. piscicida T3SS protein EseJ inhibits adhesion and invasion of E. piscicida by suppressing type 1 fimbria. However, how EseJ suppresses type 1 fimbria remains elusive. In this study, a lacI-like operator (nt -245 to -1 of fimA) upstream of type 1 fimbrial operon in E. piscicida was identified, and EseJ inhibits type 1 fimbria through the lacI-like operator. Moreover, through DNA pull-down and electrophoretic mobility shift assay, an AraC-type T3SS regulator, EsrC, was screened and verified to bind to nt -145 to -126 and nt -50 to -1 of fimA, suppressing type 1 fimbria. EseJ is almost abolished upon the depletion of EsrC. EsrC and EseJ impede type 1 fimbria expression. Intriguingly, nutrition and microbiota-derived indole activate type 1 fimbria through downregulating T3SS, alleviating EsrC or EseJ's inhibitory effect on lacI-like operator of type 1 fimbrial operon. By this study, it is revealed that upon entering the gastrointestinal tract, rich nutrients and indole downregulate T3SS and thereof upregulate type 1 fimbria, stimulating efficient adhesion and invasion; upon being internalized into epithelium, the limit in indole and nutrition switches on T3SS and thereof switches off type 1 fimbria, facilitating effector delivery to guarantee E. piscicida's survival/replication in vivo.IMPORTANCEIn this work, we identified the lacI-like operator of type 1 fimbrial operon in E. piscicida, which was suppressed by the repressors-T3SS protein EseJ and EsrC. We unveiled that E. piscicida upregulates type 1 fimbria upon sensing rich nutrition and the microbiota-derived indole, thereof promoting the adhesion of E. piscicida. The increase of indole and nutrition promotes type 1 fimbria by downregulating T3SS. The decrease in EseJ and EsrC alleviates their suppression on type 1 fimbria, and vice versa.

Orf1B controls secretion of T3SS proteins and contributes to Edwardsiella piscicida adhesion to epithelial cells.

Edwardsiella piscicida is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish. The type III secretion system (T3SS) is one of its two most important virulence islands. T3SS protein EseJ inhibits E. piscicida adhesion to epithelioma papillosum cyprini (EPC) cells by negatively regulating type 1 fimbria. Type 1 fimbria helps E. piscicida to adhere to fish epithelial cells. In this study, we characterized a functional unknown protein (Orf1B) encoded within the T3SS gene cluster of E. piscicida. This protein consists of 122 amino acids, sharing structural similarity with YscO in Vibrio parahaemolyticus. Orf1B controls secretion of T3SS translocon and effectors in E. piscicida. By immunoprecipitation, Orf1B was shown to interact with T3SS ATPase EsaN. This interaction may contribute to the assembly of the ATPase complex, which energizes the secretion of T3SS proteins. Moreover, disruption of Orf1B dramatically decreased E. piscicida adhesion to EPC cells due to the increased steady-state protein level of EseJ within E. piscicida. Taken together, this study partially unraveled the mechanisms through which Orf1B promotes secretion of T3SS proteins and contributes to E. piscicida adhesion. This study helps to improve our understanding on molecular mechanism of E. piscicida pathogenesis.

Construction of spin-crossover dinuclear cobalt(II) compounds based on complementary terpyridine ligand pairing.

The self-assembly of multinuclear SCO complexes is appealing in which unique properties may be discovered due to enhanced intramolecular and intermolecular interactions. In this work, three dinuclear cobalt(II) complexes, named Co-1, Co-2, and Co-3, were prepared based on a complementary terpyridine ligand pair strategy. The complexes were accurately synthesized by the solvothermal method in which dinuclear complexes were directional assemblies from cobalt(II) ions, terpy bearing 2,6-dimethoxyphenyl substituents at the terpyridyl 6,6''-positions, and ditopic terpy built with different linkers (alkynyl for 1, diynyl for 2, and phenyl for 3). Single-crystal structure determinations reveal that all compounds possess a central symmetric molecular structure, so that two cobalt(II) units are identical in the solid state. Their spin crossover behaviours were investigated through variable-temperature magnetic susceptibility studies. Co-1 undergoes limited SCO with a large population of low spin state (S = 1/2) in the measured temperatures. Co-2 and Co-3 exhibit solvent-modulated SCO behaviour. Impressively, the de-solvated samples show a repeatable thermal hysteresis loop around the room temperature region. This work demonstrates that complementary terpyridine ligand pairing is a practical approach to accurate and directional construction of multinuclear SCO-active compounds.

Evolutionary analysis of chloroplast tRNA of Gymnosperm revealed the novel structural variation and evolutionary aspect.

Gymnosperms such as ginkgo, conifers, cycads, and gnetophytes are vital components of land ecosystems, and they have significant economic and ecologic value, as well as important roles as forest vegetation. In this study, we investigated the structural variation and evolution of chloroplast transfer RNAs (tRNAs) in gymnosperms. Chloroplasts are important organelles in photosynthetic plants. tRNAs are key participants in translation where they act as adapter molecules between the information level of nucleic acids and functional level of proteins. The basic structures of gymnosperm chloroplast tRNAs were found to have family-specific conserved sequences. The tRNAΨ -loop was observed to contain a conforming sequence, i.e., U-U-C-N-A-N2. In gymnosperms, tRNAIle was found to encode a "CAU" anticodon, which is usually encoded by tRNAMet. Phylogenetic analysis suggested that plastid tRNAs have a common polyphyletic evolutionary pattern, i.e., rooted in abundant common ancestors. Analyses of duplication and loss events in chloroplast tRNAs showed that gymnosperm tRNAs have experienced little more gene loss than gene duplication. Transition and transversion analysis showed that the tRNAs are iso-acceptor specific and they have experienced unequal evolutionary rates. These results provide new insights into the structural variation and evolution of gymnosperm chloroplast tRNAs, which may improve our comprehensive understanding of the biological characteristics of the tRNA family.

Establishment of a Rapid Detection Method for Rice Blast Fungus Based on One-Step Loop-Mediated Isothermal Amplification (LAMP).

Rice blast is one of the most serious diseases for rice, and controlling the filamentous fungus Magnaporthe oryzae that causes rice blast is crucial for global food security. Typically, early infected rice does not show symptoms. Therefore, the early diagnosis of rice blast is particularly important to avoid uncontrollable propagation of rice blast fungus. In the present work, a rapid and efficient loop-mediated isothermal amplification (LAMP) method was developed to detect the pathogen at the early infected stage of rice. The Alb1 superfamily hypothetical protein MGG_04322, a nuclear shuttling factor involved in ribosome and melanin biogenesis, was chosen as the target for designing the LAMP primers. The LAMP assay enabled rapid detection of as little as 10 pg of pure genomic DNA of M. oryzae. In addition, we established the quantitative LAMP (q-LAMP) detection system to quantify the conidia of rice blast fungus. The q-LAMP assay enabled rapid detection (within 35 min) of the fungal spores at a sensitivity of 3.2 spores/ml. In addition, the assay sets up the linearization formula of the standard curve as y = 0.3066 + 15.33x (where x = amplification of time), inferring that spore number = 100.60y. In addition, the q-LAMP assay was successfully used to detect the presence of the virulence strains of M. oryzae (wild type) in comparison with that of the two mutant strains by quantifying the biomass within host tissue. These results provide a useful and convenient tool for detecting M. oryzae that could be applied in the incubation period of rice blast before symptoms appear.

Molecular Characterization and Comparative Pathogenicity of Goose Parvovirus Isolated from Jilin Province, Northeast China.

Goose parvovirus (GPV) is a highly contagious disease caused by GPV in goslings and young Muscovy ducklings. In recent years, frequent GPV outbreaks have occurred in many regions of Jilin Province, China. In this study, to understand the immune-related characteristics of the currently prevailing GPV strains in some regions of Jilin Province, six GPV strains were isolated from six different regions of Jilin Province in 2016-2018. The results of phylogenetic analysis, clinical signs, and histopathologic analysis showed that four strains were virulent and two strains were attenuated. Specifically, we found that the two attenuated strains have the same amino acid mutation at the same position in the virus protein 3 (VP3) gene, and the virulent strains have more mutation sites than the attenuated strains. This finding suggests that changes in these sites may result in GPV replication or reduction in the immune response in goslings, thereby producing strong pathogenicity, and that attenuated strains are more conservative than virulent strains.

Caracterización molecular y patogenicidad comparativa de parvovirus de ganso aislados en la provincia de Jilin, noreste de China. El parvovirus del ganso (GPV, por sus siglas en inglés) es una enfermedad altamente contagiosa causada por el parvovirus de ganso en gansitos y patitos reales jóvenes. En los últimos años, se han presentado brotes frecuentes por el parvovirus del ganso en muchas regiones de la provincia de Jilin, en China. En este estudio, para comprender las características relacionadas con el sistema inmunológico de las cepas del parvovirus del ganso prevalentes actualmente en algunas regiones de la provincia de Jilin, se aislaron seis cepas de parvovirus del ganso de seis regiones diferentes de la provincia de Jilin entre los años 2016 al 2018. Los resultados del análisis filogenético, los signos clínicos y el análisis histopatológico mostraron que las cuatro cepas fueron virulentas y dos fueron atenuadas. Específicamente, se encontró que las dos cepas atenuadas tienen la misma mutación de aminoácidos en la misma posición en el gene de la proteína viral 3 (VP3) y las cepas virulentas tienen más sitios de mutación que las cepas atenuadas. Este hallazgo sugiere que los cambios en estos sitios pueden resultar en la replicación o reducción de la respuesta inmune en los gansitos, lo que induce una fuerte patogenicidad y que las cepas atenuadas son más conservadas que las virulentas.

Chaenomeles speciosa: A review of chemistry and pharmacology.

Chaenomeles speciosa (Sweet) Nakai (C. speciosa, Rosaceae family) is an effective medicinal plant, which has long been used in China to treat various diseases, such as rheumatism, cholera, dysentery, enteritis, beriberi and vitamin C deficiency syndrome. A series of chemical constituents, including triterpenoid, phenolic and phenylpropionic acids, flavonoids, saccharides, essential oils and alkaloids, have been isolated from this plant and some have already been evaluated for their biological activities. Pharmacological investigations demonstrated that C. speciosa possesses anti-inflammatory, antinociceptive, antimicrobial, antioxidant, immunoregulatory, antiparkinsonian, hepatoprotective and antitumor properties. The objective of this review was to summarise available up-to-date and comprehensive information on C. speciosa and provide a relevant reference for further investigations.

One-step detection of Bean pod mottle virus in soybean seeds by the reverse-transcription loop-mediated isothermal amplification.

BACKGROUND: Bean pod mottle virus (BPMV) is a wide-spread and destructive virus that causes huge economic losses in many countries every year. A sensitive, reliable and specific method for rapid surveillance is urgently needed to prevent further spread of BPMV. METHODS: A degenerate reverse-transcription loop-mediated isothermal amplification (RT-LAMP) primer set was designed on the conserved region of BPMV CP gene. The reaction conditions of RT-LAMP were optimized and the feasibility, specificity and sensitivity of this method to detect BPMV were evaluated using the crude RNA rapidly extracted from soybean seeds. RESULTS: The optimized RT-LAMP parameters including 6 mM MgCl2, 0.8 M betaine and temperature at 62.5-65°C could successfully amplify the ladder-like bands from BPMV infected soybean seeds. The amplification was very specific to BPMV that no cross-reaction was observed with other soybean viruses. Inclusion of a fluorescent dye makes it easily be detected in-tube by naked eye. The sensitivity of RT-LAMP assay is higher than the conventional RT-PCR under the conditions tested, and the conventional RT-PCR couldn't be used for detection of BPMV using crude RNA extract from soybean seeds. CONCLUSION: A highly efficient and practical method was developed for the detection of BPMV in soybean seeds by the combination of rapid RNA extraction and RT-LAMP. This RT-LAMP method has great potential for rapid BPMV surveillance and will assist in preventing further spread of this devastating virus.

Essential oil from rhizomes of Ligusticum chuanxiong induces apoptosis in hypertrophic scar fibroblasts.

CONTEXT: Hypertrophic scarring following surgical procedures, trauma and especially burns can lead to severe functional and cosmetic impairment, causing a decrease in the quality of life. Although a wide choice of treatments is offered, few therapeutic methods are universally accepted because of their side effects. OBJECTIVE: The effects of the essential oil (EO) extracted from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) in human hypertrophic scar fibroblasts (HSFs) are investigated for the first time. MATERIALS AND METHODS: Chemical composition of hydrodistilled EO obtained from rhizomes of Ligusticum chuanxiong was analyzed by gas chromatography-mass spectrometry (GC-MS). The effects of EO on cell viability, apoptosis rate, mitochondrial membrane potential (MMP), lactate dehydrogenase (LDH), reactive oxygen species (ROS) and caspase-3 in HSFs were investigated. RESULTS: The experimental results showed that EO significantly inhibited cell viability, elicited morphological changes and induced apoptosis in HSFs. EO also evidently increased the loss of MMP, the levels of LDH release and cellular ROS production, and the activity of caspase-3. DISCUSSION AND CONCLUSION: EO-induced apoptosis was at least partially carried out via destruction of the intracellular antioxidant system and elicitation of excessive ROS accumulation in HSFs, which impaired mitochondrial membranes and elicited caspase-3 activation. EO could be an effective cure for human hypertrophic scar.

[A case-control study on risk factors for tuberculosis in Yinchuan city].

OBJECTIVE: To study the risk factors of tuberculosis in Yinchuan city and lay a basis for its prevention and control. METHODS: A matched case-control (119:179) study for the risk factors was carried out. Data were analyzed with single-variable analysis and multiple factor logistic regression analysis. RESULTS: Single-variable analysis showed that the education background (chi2 = 2.363, P = 0.018), family economic income (chi2 = 3.040, P = 0.002), smoking (chi2 = 2.500, P = 0.012), physical activities (chi2 = 2.330, P = 0.020), bacille Calmette-Guerin (BCG) vaccination history (chi2 = 22.151, P = 0.000), history of exposure to tuberculosis (chi2 = 15.740, P = 0.000) and so on had significant effects on tuberculosis. Multiple logistic regression analysis showed that family monthly income, smoking, physical activity, BCG vaccination history, history of exposure to tuberculosis entered the final regression model (chi2 = 5.880, 7.368, 3.891, 21.127, 14.536; OR = 0.529, 1.571, 0.774, 0.264, 3.978; P < 0.05). CONCLUSION: History of exposure to tuberculosis and smoking should be the risk factors of tuberculosis in Yinchuan. Having much income, physical activities, and BCG vaccination history should be the preventive factors.