OmpR (TCS response regulator) of Aeromonas veronii plays a major role in drug resistance, stress resistance and virulence by regulating biofilm formation.

Aeromonas veronii (A. veronii), a highly pathogenic bacteria with a wide range of hosts, widely exists in the environment of humans, animals and aquatic animals, and can cause a variety of diseases. In this study, the receptor regulator ompR in the envZ/ompR of two-component system was selected to construct a mutant strain (Δ ompR) and a complement strain (C-ompR) to explore the regulatory effect of ompR on the biological characteristics and virulence of TH0426. The results showed that the ability of biofilm formation and osmotic stress of TH0426 were significantly reduced (P < 0.001), the resistance to ceftriaxone and neomycin were slightly down-regulate when the ompR gene was deleted. At the same time, animal pathogenicity experiments showed that the virulence of TH0426 was significantly down-regulated (P < 0.001). These results indicated that ompR gene regulates the biofilm formation of TH0426, and regulates some biological characteristics of TH0426, including drug sensitivity, resistance to osmotic stress, and also affects its virulence.

Pathogenic characteristics of bloodstream infections in patients with hematological diseases and the impact of stem cell transplantation on them / 中国热带医学

@#Abstract: Objective To investigate the epidemiological characteristics of pathogens causing bloodstream infection in hematology patients during treatment and to compare the effects of allogeneic hematopoietic stem cell transplantation (HSCT) on them, so as to provide evidence for the diagnosis and treatment of bloodstream infection. Methods A total of 292 cases with bloodstream infection in hematology wards of the PLA General Hospital were collected from 2017 to 2021, which were divided into HSCT group and N-HSCT group according to whether performed HSCT or not. The epidemiological characteristics and influence of pathogenic bacteria in blood stream infection were analyzed and compared between the two groups. Results A total of 362 strains of pathogenic bacteria were collected from 292 cases, including 106 strains in HSCT group (84 cases) and 256 strains in N-HSCT group (208 cases). Bloodstream infections were more common in acute myeloid leukemia (130/392, 44.52%), followed by non-Hodgkin's lymphoma (74/292, 25.34%). The rate of once bloodstream infection in HSCT group was higher than that in N-HSCT Group, but the rate of twice bloodstream infections in N-HSCT group was higher. Gram-negative Bacilli were the most common pathogens (56.08%), with Escherichia coli being absolutely dominant (109/362, 30.11%), followed by Klebsiella pneumoniae (39/362, 10.77%). Coagulase-negative staphylococci (CoNS) (107/362, 29.56%) were the most common Gram-positive cocci. The detection rate of fungi in HSCT group (10/106, 9.43%) was significantly higher than that in N-HSCT Group (3.52%). The drug resistance rate of the common pathogenic bacteria was at a high level, and there was a certain proportion of multi-drug resistant strains (except for Pseudomonas aeruginosa). The resistance rates of CoNS to penicillin, gentamicin, moxifloxacin, clindamycin and rifampicin in HSCT group were higher than those in N-HSCT Group. The resistance rate of Escherichia coli to piperacillin/tazobactam, cephalosporins and etapenem in HSCT group was significantly higher than that in N-HSCT group. Conclusions The pathogens of blood stream infection in hematology patients are complicated and various. It is difficult for clinical diagnosis and treatment to detect multiple infections and multiple pathogens. HSCT patients have a higher risk of fungal bloodstream infection and more multi-drug resistant strains detected. Therefore, the identification of bloodstream infection and multi-drug resistant strains associated with HSCT patients should prompt surveillance.

Prevalence of Cryptosporidium Infection in Sheep and Goat Flocks in China During 2010-2019: A Systematic Review and Meta-Analysis.

Cryptosporidiosis is an extensively contagious zoonotic waterborne disease caused by the genus Cryptosporidium and poses to be a danger to public health. Sheep and goats are an intermediate host of Cryptosporidium. Consequently, a first systematic review and meta-analysis are performed to assess the burden of the infection relative to the Cryptosporidium in sheep and goat flocks in China. Five databases were searched for relevant literature in accordance with the inclusion criteria until January 30, 2020. At last, a total of 33 qualified documents were included. We calculate the overall prevalence of Cryptosporidium (4.9%) in sheep and goats in China with the random-effects model. The prevalence after 2014 (4.6%) was higher than that before or in 2014 (2.8%). The pooled prevalence of Cryptosporidium in sheep and goats from Northern China (12.3%) was significantly higher (p < 0.05) than other regions. The infection rate of modified acid-fast staining (14.3%) was the highest among the detection methods. In age subgroups, the prevalence of Cryptosporidium in sheep and goats in 3 months or before was the highest (20.8%). Goats had a higher infection rate (5.9%) in species. The prevalence of large-scale farms (2.8%) was lower than free-ranging farms (4.4%). The medium quality level (6.4%) was the highest. Besides, geographical factors (such as latitude, longitude, height, precipitation, humidity, mean temperature, etc.) were further analyzed as potential risk factors of Cryptosporidium in sheep and goats. This meta-analysis indicates that the Cryptosporidium infection of Chinese sheep and goat flocks is general. Thus, it is necessary to further monitor the prevalence of Cryptosporidium, and the reasonable preventive strategy should be formulated on the basis of the geographical factors of different regions and the differences in sheep and goats' growth stages to reduce the prevalence of Cryptosporidium in sheep and goats.

Transcriptome Analysis of Epithelioma Papulosum Cyprini Cells Infected by Reovirus Isolated from Allogynogenetic Silver Crucian Carp.

The present study aimed to identify differentially expressed genes (DEGs) and major signal transduction pathways that were related to the immune response of epithelioma papulosum cyprinid (EPC) cells to reoviruses isolated from allogynogenetic silver crucian carp. The study also lays a theoretical foundation for the pathogenesis and immunity of the reovirus, which is helpful to the breeding of cyprinids fish. Reovirus infected and uninfected EPC cells were analyzed by using a new-generation high-throughput sequencing technology. DEGs were identified, annotated, and classified, and the signal pathways involved in the response to reovirus infection were identified by using bioinformatics tool. The data were assembled into 92,101 contigs with an average length of 835.24 bp and an N50 value of 1432 nt. Differential expression analysis of all the genes identified 3316 DEGs at a false discovery rate (FDR) of <0.01 and a fold-change of ≥3, of which 1691 were upregulated genes, 1625 were downregulated, and about 305 were immune-related genes. Gene Ontology (GO) enrichment analysis resulted in the annotation of 3941 GO terms, including 2719 biological processes (37,810 unigenes), 376 cell components (7943 unigenes), and 846 molecular functions (11,750 unigenes). KEGG metabolic pathway analysis matched the DEGs from pre-and post-infection EPC cells to 193 pathways, of which 35 were immune-related, including the Toll-like receptor, cytokine-cytokine receptor interaction, and the JAK-STAT signaling pathways.

Molecular Characterization of Enterocytozoon bieneusi in Domestic Rabbits (Oryctolagus cuniculus) in Northeastern China.

A study of 426 rabbits from 3 cities in Jilin province (Changchun City and Jilin City) and Liaoning province (Shenyang City) was conducted between May and June 2015. The overall prevalence of E. bieneusi in rabbits was 0.94% (4/426), with 0% (0/116), 1.72% (3/174), and 0.74% (1/136) in Jilin, Changchun, and Shenyang City, respectively. Only 3 farms (farm 1 and farm 3 in Changchun City, farm 8 in Shenyang City) were PCR-positive for E. bieneusi. Moreover, rabbits of more than 6 months (1.72%) had the highest E. bieneusi prevalence, followed by rabbits of 4-6 months (1.26%), 2-3 months (0.58%), and less than 1 month (0%). Analysis of ITS gene of E. bieneusi suggested that all 4 E. bieneusi isolates were genotype D, and were classified as group 1a. The present results first demonstrated the existence of zoonotic E. bieneusi in domestic rabbits in China. Effective control measures should be implemented to prevent E. bieneusi infection in domestic rabbits, other animals, and humans.

[Dynamic Changes of Dectin-2 Expression on Dendritic Cells in Mice Infected with Trichinella spiralis].

Objective: To investigate the effect of Trichinella spiralis infection on dectin-2 expression on dendritic cells (DC) in mice. Methods: Seventy-two female BABL/c mice were randomized into experimental and control groups (n=36 in each), and received intragastric administration of 200 muscle larvae of Trichinella spiralis and PBS respectively. Six animals were each sacrificed on days 7, 14, 21, 28, 35 and 42 after administration. The spleen and mesenteric lymph nodes (MLN) were dissected and single cell suspensions were prepared. The expression of dectin-2 on DC in the spleen and MLN was examined by flow cytometry. In another experiment, bone marrow was obtained from C57BL/6 mice, and was treated with granulocyte-macrophage colony-stimulating factor and interleukin 4 to induce bone marrow-derived dendritic cells (BMDC) in vitro. Then 100 µg/ml T. spiralis excretory/secretory (ES) antigen or the same volume of PBS was added. The expression of dectin-2 was determined by flow cytometry at 6, 12, 24, 36 and 48 h. Results: The flow cytometry results showed a significant decrease of dectin-2 expression［（7.0±0.7）%ï¼½ on spleen DC compared with that of the control group［（15.1±1.6）%］（P<0.01） on day 7, and significant increase of dectin-2 on MLNDC compared with that of the control on days 7, 21 and 28 ［（11.1±3.5）% vs. （6.6±0.4）%, （12.4±1.4）% vs. （4.9±0.4）%, （6.9±1.0）% vs. （4.0±1.4）%ï¼½ （P<0.05） after infection. In vitro results showed that dectin-2 expression was （9.4±2.2）%, （6.9±1.8）%, （6.9±0.7）%, （9.1±1.9）%, and（15.9±1.9）% respectively at 6, 12, 24, 36, and 48 h after ES stimulation on BMDC. The expression at 6, 12, 24 and 36 h decreased significantly in comparison to that of the PBS group［（21.3±6.3）%］（P<0.01). Conclusion: Trichinella infection can induce changes of dectin-2 expression on DC of mice.

Serological tools for detection of Trichinella infection in animals and humans.

Trichinellosis is a serious foodborne zoonotic disease. It is an important threat to public health in both developing and developed countries. Human infections are strongly associated with consuming undercooked meat containing infective Trichinella larvae. The development of serological tools has enabled seroepidemiological studies and contributed to our knowledge on the importance of this parasite. Serological tests can also help the diagnosis of parasite infections in humans and the surveillance of animals. Generally speaking, serological techniques include detection methods for specific antibodies and for circulating parasite antigens in the serum or tissue fluids. Here, we present a comprehensive review of various methods used in the detection of antibodies against Trichinella and circulating parasite antigens in animals and humans.

Seroprevalence and risk factors of Toxoplasma gondii infection in stray dogs in northern China.

Toxoplasma gondii is a zoonotic protozoan of almost all species of mammals and birds. However, no information is available about seroprevalence of the pathogen in stray dogs in seven cities from Inner Mongolia, Jilin, Liaoning province, China. Using the indirect hemagglutination antibody (IHA) test with a cutoff titer of 1:64, 129 (14.05 %) out of 918 stray dogs were surveyed to be T. gondii seropositive. Analysis of the risk factor showed that there was no statistical difference of seroprevalence of T. gondii between males (13.46 %) and females (14.54 %) (P > 0.05). The seropositive rates of T. gondii infection in stray dogs among the seven cities in northern China were significant statistically different (P = 0.005). Moreover, seroprevalence of T. gondii in dogs were varied from 11.01 % (95 % CI 6.94-15.09) to 16.86 % (95 % CI 12.27-21.46) among different age groups, and the difference was statistically significant (P = 0.03). More importantly, T. gondii seropositive in stray dogs has a declining tendence from 2011 to 2015 (P = 0.004). The results of the present study showed that stray dogs in Inner Mongolia, Jilin, Liaoning province, China are exposed to T. gondii, for the first time, and could also provide a foundation data for prevent and control T. gondii infection in dogs, other animals and humans.

Serine proteases of parasitic helminths.

Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed.

[Inhibitory effect of icariin on acetylcholinesterase].

Acetylcholinesterase (AChE) inhibitors are mainly used in the treatment of Alzheimer's disease (AD). The inhibitory effect of icariin on the activity of AChE was investigated by inhibition kinetics. The binding interaction and binding sites between icariin and AChE were also studied by using fluorimetry and molecular docking, respectively. The results showed that icariin could potently inhibit the activity of AChE, the IC50 value was determined to be 3.50 x 10(-8) mol x L(-1), and the determined IC50 value to tacrine was 0.75 x 10(-8) mol x L(-1). Kinetic analyses showed that icariin is a reversible and mixed type AChE inhibitor. The inhibition constants K1 and K(IS) were determined to be 2.67 x 10(-8) and 4.43 x 10(-8) mol x L(-1), respectively. Icariin binds selectively to the AChE peripheral anionic site via hydrogen bonds and Van der Waals forces.

Ultrastructure and electrophysiology of astrocytes differentiated from adult adipose-derived stromal cells.

BACKGROUND: Adipose-derived stromal cell (ADSC) differentiation into neural cells in vitro is becoming widely studied. However, there are few reports on astrocytes following differentiation, and particularly on maturation and electrophysiology. In this study, we used various methods to determine ADSC-derived astrocyte maturity. METHODS: Chemical induction with isobutylmethylxanthine (IBMX) was used to differentiate adult ADSCs into astrocytes followed by hematoxylin-eosin (HE) staining to observe morphology and transmission electron microscopy for cellular ultrastructure assessment. Immunofluorescence was used to detect expression of neural stem cell marker nestin as well as glial markers glial fibrillary acidic protein (GFAP) and S-100. In addition, we measured membrane potentials in bis-(1,3-dibarbituric acid) trimethine oxanol-labeled ADSCs and astrocytes by stimulation with a high potassium solution under an inverted fluorescence microscope. Finally, cell cycle distribution was detected by flow cytometry. RESULTS: Typical astrocyte morphology was shown by HE staining after 48-hour differentiation. Glial fibril was observed with transmission electron microscopy. GFAP and S-100 were not expressed in the control group, but were expressed within 24-hour differentiation and reached a maximum at day 14 with no change up to day 28. Nestin was weakly expressed in control cells and also reached a maximum at day 14 with the percentage of positive cells constant until day 21 followed by a decrease. Differentiated cell membrane potentials after stimulation with potassium were slightly increased, and then gradually declined over time. There was no significant membrane potential change in the control group. Flow cytometry showed that the percentage of cells in G0/G1 phase was 93% and only 5% in S phase. CONCLUSION: ADSCs were differentiated into mature astrocytes with typical characteristics including morphology, ultrastructure, marker protein expression, mature potassium channels and mitotic capacity.

[The apoptosis of human gastric cancer cell induced by Acanthopanax giraldii Harms var Hispidus Hoo Polysaccharides in vitro].

OBJECTIVE: To investigate the effect of Acanthopanax Giraldii Harms Var Hispidus Hoo polysaccharides (AGP-I) on the human gastric cancer cell. METHODS: DNA agarose gel electrophoresis and flow cytometry techniques were adopted. RESULTS: After treatment with AGP-I, apoptotic peaks in cell cycle analysis and DNA ladder on the agarose gel were observed. CONCLUSION: The results indicate that AGP-1 may inhibit cancer by inducing cancer cell apoptosis.