Alongshan Virus Infection in Rangifer tarandus Reindeer, Northeastern China.

We investigated Alongshan virus infection in reindeer in northeastern China. We found that 4.8% of the animals were viral RNA-positive, 33.3% tested positive for IgG, and 19.1% displayed neutralizing antibodies. These findings suggest reindeer could serve as sentinel animal species for the epidemiologic surveillance of Alongshan virus infection.

Nanoscale dihydroartemisinin@zeolitic imidazolate frameworks for enhanced antigiardial activity and mechanism analysis.

An artificial semisynthetic material can be derived from artemisinin (ART) called dihydroartemisinin (DHA). Although DHA has enhanced antigiardial potential, its clinical application is limited because of its poor selectivity and low solubility. The drug's absorption has a direct impact on the cell, and mechanism research is limited to its destruction of the cytoskeleton. In this study, we used the zeolitic imidazolate framework-8 and loaded it with DHA (DHA@Zif-8) to improve its antigiardial potential. DHA@Zif-8 can enhance cellular uptake, increase antigiardial proliferation and encystation, and expand the endoplasmic reticulum compared with the DHA-treated group. We used RNA sequencing (RNA-seq) to investigate the antigiardial mechanism. We found that 126 genes were downregulated and 123 genes were upregulated. According to the KEGG and GO pathway analysis, the metabolic functions in G. lamblia are affected by DHA@Zif-8 NPs. We used real-time quantitative reverse transcription polymerase chain reaction to verify our results using the RNA-seq data. DHA@Zif-8 NPs significantly enhanced the eradication of the parasite from the stool in vivo. In addition, the intestinal mucosal injury caused by G. lamblia trophozoites markedly improved in the intestine. This research provided the potential of utilizing DHA@Zif-8 to develop an antiprotozoan drug for clinical applications.

[Ginsenoside F1 inhibits cholesterol overload in oxidative-damaged cells through SREBP2/HMGCR pathway].

OBJECTIVE: To investigate the inhibitory mechanisms of ginsenoside F1 on hydrogen peroxide induced cholesterol metabolism disorder and oxidative stress in HepG2 cells. METHODS: 1, 1-diphenyl-2-picrylhydrazyl(DPPH) and oxygen radical absorbance capacity(ORAC) tests were used to detect the scavenging effect of ginsenoside F1 on nitrogen and oxygen free radicals. HepG2 cells were treated with 400 µmol/L hydrogen peroxide and pretreated with 10, 20 and 40 µmol/L ginsenoside F1. Mitochondrial membrane potential(MMP) and total cholesterol levels were detected by JC-1 method and cholesterol kit, respectively. The protein expression levels of sterol-regulatory element binding proteins(SREBP2)and 3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR) in cholesterol synthesis pathway were detected by Western blot. RESULTS: The DPPH clearance rate of ginsenoside F1 was much lower than that of 6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid(Trolox), but the ORAC capability of ginsenoside F1 was stronger, which was comparable to Trolox. The MMP and protein expression of SREBP2 were significantly decreased in injured group(P<0.05). The cholesterol and protein expression of HMGCR were significantly increased(P<0.05). Whereas, compared with the injured group, the MMP and protein expression of SREBP2 were significantly increased after 10, 20 and 40 µmol/L ginsenoside F1 pretreatment of injured cells(P<0.05). The cholesterol level and protein expression of HMGCR were significantly lower than injured group with concentration-dependent decreases(P<0.05). CONCLUSION: Ginsenoside F1 can protect against hydrogen peroxide induced oxidative stress in HepG2 cells by inhibiting oxygen free radicals and protecting mitochondria. And its mechanism may be related to the intervention of SREBP2/HMGCR pathway in regulating cellular cholesterol anabolism.

Self-assembly and self-delivery of the pure nanodrug dihydroartemisinin for tumor therapy and mechanism analysis.

Dihydroartemisinin (DHA), a plant-derived natural product, has recently been proven to be an effective therapeutic agent for cancer treatment. Nevertheless, the poor water solubility and low bioavailability of DHA seriously impede its clinical applications. Herein, a simple and green strategy based on the self-assembly of DHA was developed to synthesize carrier-free nanoparticles (NPs). The resulting nanodrug (DHA NPs) was formed by the self-assembly of DHA molecules via hydrogen bonding and hydrophobic interactions. The DHA NPs exhibited a near-spherical morphology with narrow size distribution, favorable drug encapsulation efficiency (>92%), excellent stability, and on-demand drug release behavior. Furthermore, the in vitro and in vivo experiments revealed that the DHA NPs exhibited significantly higher therapeutic efficacy than the DHA equivalent. In addition, we further explored the potential molecular mechanism of the DHA NPs by utilizing RNA-seq technology and western blotting analysis, which demonstrated that the p53 signaling pathway plays a crucial part in the process of inhibiting tumor cell growth and inducing apoptosis. This work not only reveals the rationale for developing pure nanodrugs via the self-assembly of natural small molecules for oncotherapy but also the investigation of the antitumor mechanism and provides novel theoretical support for the clinical usage of DHA.

A redox-responsive dihydroartemisinin dimeric nanoprodrug for enhanced antitumor activity.

Redox-responsive drug delivery system emerges as a hopeful platform for tumor treatment. Dihydroartemisinin (DHA) has been investigated as an innovative tumor therapeutic agent. Herein, a DHA dimeric prodrug bridged with disulfide bond as linker (DHA2-SS) has been designed and synthesized. The prepared prodrugs could self-assemble into nanoparticles (SS NPs) with high DHA content (> 90%) and robust stability. These SS NPs display sensitive redox responsive capability and can release DHA under the tumor heterogeneity microenvironment. SS NPs possess preferable antitumor therapeutic activity in contrast with free DHA. Moreover, the possible anti-cancer mechanism of SS NPs was investigated through RNA-seq analysis, bioinformatics and molecular biological method. SS NPs could induce apoptosis via mitochondrial apoptosis pathway, as well as glycolysis inhibition associate with the regulation of PI3K/AKT/HIF-1α signal path, which may offer an underlying therapeutic target for liver cancer. Our study highlights the potential of using redox responsive prodrug nanoparticles to treat cancer, meanwhile provides insights into the anti-cancer mechanism of DHA prodrug.

Global Lysine Acetylation and 2-Hydroxyisobutyrylation Profiling Reveals the Metabolism Conversion Mechanism in Giardia lamblia.

Giardia lamblia (G. lamblia) is the cause of giardiasis, a common infection that affects the general population of the world. Despite the constant possibility of damage because of their own metabolism, G. lamblia has survived and evolved to adapt to various environments. However, research on energy-metabolism conversion in G. lamblia is limited. This study aimed to reveal the dynamic metabolism conversion mechanism in G. lamblia under sugar starvation by detecting global lysine acetylation (Kac) and 2-hydroxyisobutyrylation (Khib) sites combined with quantitative proteome analyses. A total of 2999 acetylation sites on 956 proteins and 8877 2-hydroxyisobutyryl sites on 1546 proteins were quantified under sugar starvation. Integrated Kac and Khib data revealed that modified proteins were associated with arginine biosynthesis, glycolysis/gluconeogenesis, and alanine, aspartate, and glutamate metabolisms. These findings suggest that Kac and Khib were ubiquitous and provide deep insight into the metabolism conversion mechanism in G. lamblia under sugar starvation. Overall, these results can help delineate the biology of G. lamblia infections and reveal the evolutionary rule from prokaryote to eukaryote.

Supramolecular hybrids of carbon dots and dihydroartemisinin for enhanced anticancer activity and mechanism analysis.

Dihydroartemisinin (DHA) has been regarded as a potential anticancer agent in recent years. Nevertheless, the clinical applications of DHA are seriously restricted as a result of its intrinsic characteristics, such as poor water solubility, instability, and fast clearance. Herein, a type of fluorescent nanoparticles was successfully fabricated via supramolecular assembling of carbon dots (CDs) and DHA. The formulated CDs-DHA fluorescent nanoparticles not only significantly improve the solubility and stability of DHA, but also possess favorable biocompatibility and pH-dependent drug release behavior. In particular, the hybrids of CDs and DHA as nanocarriers can effectively promote the endocytosis of DHA and exhibit enhanced antitumor effects compared with free DHA in vitro and in vivo. In addition, we also explore the possible action mechanism of CDs-DHA through flow cytometric assay, transfection and western blot analysis. The results indicate that CDs-DHA nanoparticles suppress the progression of hepatic carcinoma through inducing apoptosis and inhibiting glucose metabolism, and the mechanism is related to the downregulation of PKM2 expression and the suppression of the Akt/mTOR signaling pathway, which may provide a potential therapeutic target for hepatic carcinoma treatment. This work emphasizes the great potential of utilizing CDs as a safe and convenient platform to deliver DHA for efficient cancer therapy, and the study on the anticancer mechanism can also offer theoretical support for the clinical application of DHA.

[Corncornin-3-O-glucoside mediates the NF-κB pathway to inhibit H_2O_2-induced apoptosis].

OBJECTIVE: To study the anti-apoptotic effect of cyanidin-3-O-glucoside(C3 G) on H_2O_2-induced injury in human embryonic kidney(HEK)-293 cells. METHODS: Hydrogen peroxide induced injury of HEK-293 cell was used as the research object. HEK-293 cells were pretreated with different concentrations of C3 G(1. 25, 5, 20 µmol/L). The anti-apoptotic effects of C3 G on injured cells were examined by the release rates of LDH and mitochondrial membrane potential(MMP). Western blot and qRT-PCR were used to detect the protein expression and mRNA expression of NF-κB P65. RESULTS: The result showed that the release rate of LDH was increased, MMP was decreased, the protein and mRNA of P65 was increased after H_2O_2 inducing. Whereas, the release rates of LDH were significantly lower than that of the injured group after 1. 25, 5, 20 µmol/L C3 G pretreatment of injured cells(P<0. 05). The MMP of C3 G group was significantly higher than injured group with concentration-dependent increases. The proteins and mRNA of P65 were also significantly lower than that of injured group(P<0. 05). CONCLUSION: Cyanidin-3-O-glucoside shows anti-apoptotic effect on H_2O_2-induced injury in HEK-293 cell. The mechanisms of anti-apoptotic effects may be to achieve by protecting cell biofilms, and inhibiting the activity of NF-κB signaling pathway.

MOF nanoparticles with encapsulated dihydroartemisinin as a controlled drug delivery system for enhanced cancer therapy and mechanism analysis.

Dihydroartemisinin (DHA) has attracted increasing attention as an emerging therapeutic agent for tumor treatment. However, the clinical application of DHA is seriously limited owing to its inherent properties, including low solubility, poor selectivity, and fast clearance. Herein, we report a facile yet efficient strategy based on using zeolitic imidazolate framework-8 to load DHA (DHA@ZIF-8). The as-prepared DHA@ZIF-8 nanoparticles (NPs) possess high drug encapsulation efficiency (77.2%), favorable stability, good biocompatibility and controllable drug release in tumor acidic microenvironments. DHA@ZIF-8 NPs exhibit enhanced antitumor effects compared with free DHA in in vitro and in vivo therapy experiments, accompanied with negligible side effects. Furthermore, the antitumor mechanism of DHA@ZIF-8 NPs is well investigated by RNA sequencing (RNA-seq) and bioinformatics analysis. The results indicate that DHA@ZIF-8 NPs modify the expression of 7090 genes in HepG2 cells, and the mechanism may be related to the induction of apoptosis through a p53-mediated mitochondrial pathway and the suppression of glycolysis by inhibiting the PI3K/AKT pathway. This work highlights the potential of utilizing MOFs as a safe and stable platform for developing a highly efficient drug delivery system in cancer therapy, and the investigation of the antitumor mechanism can provide theoretical support for the clinical usage of DHA.

Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii.

Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully understood. This study aimed to determine the biological functions of heat shock protein (HSP)-20 of A. castellanii (Ac-HSP20) involved in the maintenance of life cycle and the infectivity of A. castellanii. Immunoscreening A. castellanii cDNA library with A. castellanii infected rabbit sera identified three positive clones, one of them was a putative heat shock protein (Ac-HSP20). The recombinant 23 kDa Ac-HSP20 protein (rAc-HSP20) was successfully expressed in Escherichia coli BL21 (DE3) and purified using metal affinity chromatography. The rabbits immunized with rAc-HSP20 produced high titer antibody (1:25,600). Immunolocalization with the antibody identified the expression of native Ac-HSP20 on the surface of both A. castellanii trophozoites and cysts. Further, Western blot with antibody identified that the expression of native Ac-HSP20 was 7.5 times higher in cysts than in trophozoites. Blocking Ac-HSP20 on the membrane of trophozoites with specific antibody or silencing Ac-hsp20 gene transcription by siRNA inhibited their transformation into cysts at the early stage but returned to normal at the late stage by stimulating the transcription of Ac-hsp20. Incubation of trophozoites with anti-Ac-HSP20 IgG increased macrophage-involved phagocytosis to the protozoa and inhibited trophozoite infectivity on the cornea of rabbits compared with that without antibody. Our study provides that Ac-HSP20 is a surface antigen involved in the encystation and infectivity of A. castellanii and thus an important target for vaccine and drug development.

Differential distributions of parvalbumin-positive interneurons in the sulci and gyri of the adult ferret cerebral cortex.

Although accumulating evidence suggests that there are significant anatomical and histological differences between the sulci and gyri of the cerebral cortex, whether there is a difference in the distribution of interneurons between the two cortical regions remains largely unknown. In this study, we systematically compared the distributions of parvalbumin-positive interneurons among three neighboring gyrus and sulcus pairs-coronal gyrus and cruciate sulcus, anterior ectosylvian gyrus and rostral suprasylvian sulcus, and posterior ectosylvian gyrus and pseudosylvian sulcus-in the adult ferret cerebral cortex. We proposed a method to partition sulci and gyri into several specific subregions through the deepest points of the sulci and the highest points of gyri in the inner and outer cortical contours of coronal sections. We found that the density of parvalbumin-positive interneurons in the gyri was significantly higher than that in the sulci. Further study revealed that the density of PV interneurons in superficial cortical layers (layers 2/3 and layer 4) was comparable among the three pairs of sulci and gyri. However, the density of parvalbumin-positive interneurons in cortical layers 5/6 was significantly higher in gyri than in sulci. These results indicate that parvalbumin-positive interneurons are differently distributed in infragranular layers of cortical sulci and gyri.

Dihydroartemisinin suppresses glycolysis of LNCaP cells by inhibiting PI3K/AKT pathway and downregulating HIF-1α expression.

AIMS: Dihydroartemisinin (DHA) exhibits potential anticancer activity. However, the biological functions of DHA in prostate cancer remain largely unexplored. In this study, we aim to investigate the anti-proliferative effect and glycolysis regulation of DHA on prostate cancer cell LNCaP. MAIN METHODS: Cell proliferative activity and apoptosis inducing were detected. The gene expression was detected by mRNA microarray and results were analyzed by GO and KEGG pathway database. Expressions of glycolysis key enzymes and PI3K/AKT/HIF-1α were detected by Western blot. KEY FINDINGS: Results indicated that DHA could inhibit the LNCaP cell proliferation considerably and induce cell apoptosis. mRNA microarray showed 1293 genes were upregulated and 2322 genes were downregulated. GO and KEGG enrichment analysis suggested that glycolysis pathway was correlated with DHA inhibited the proliferation on the LNCaP cell. Western blot results showed that DHA can decrease GLUT1 and regulatory enzymes of glycolytic pathway expression probably by suppressing the activity of the intracellular Akt/mTOR and HIF-1 α. SIGNIFICANCE: Experimental validation results indicate that DHA treatment can inhibit the LNCaP cell proliferation and induce apoptosis, which may be related to glycolysis inhibition.

[Protective effects of ginsenoside F2 on hydrogen peroxide induced cell injury].

OBJECTIVE: To investigate the inhibitive effects of ginsenoside F2 on oxidative stress in human embryonic kidney cells(HEK-293). METHODS: Hydrogen peroxide induced oxidative stress of HEK-293 cell was used as the research object. HEK-293 cells were pretreated with different concentrations of ginsenoside F2(1.25, 5, 20 µmol/L). Cell viability was measured by MTS assay. Malondialchehyche(MDA) level and activities of antioxidant enzymes(superoxide dismutase SOD, glutathione peroxidase GSH-Px, catalase CAT) were measured by corresponding assay kits. DCFH-DA fluorescent probe assay was used to measure the level of intracellular reactive oxygen species(ROS). Quantitative real-time PCR and Western blot were used to detect the expression of nuclear factor erythroid 2-related factor 2(Nrf2) and kelch-like ECH associated protein 1(Keap1). RESULTS: After treated with 1.25, 5, 20 µmol/L ginsenoside F2, no cytotoxic or proliferative effects were shown on normal HEK-293 cells. After pretreatment with ginsenoside F2, the cell viability was significantly higher than that of the injury group(P<0.05)and increased in a concentration-dependent manner. The fluorescence intensity of oxidative DCF in injured group was significantly increased compared with control group(P<0.05). The fluorescence intensity of cells which pretreated with different concentrations of ginsenoside F2 was gradually weakened(P<0.05). The ROS content of control group was chosen as the standard, and the relative amount of ROS pretreated by ginsenoside F2 decreased in a concentration-dependent manner. After pretreatment of ginsenoside F2, the MDA levels decreased in a concentration-dependent manner and the activities of SOD and GSH-Px were significantly higher than those of the injured group(P<0.05). The activity of CAT was significantly increased with pretreatment of higher concentrations of ginsenoside F2(P<0.05). Furthermore, ginsenoside F2 significantly enhanced the protein and mRNA expressions of Nrf2 and reduced the expressions of Keap1 in a dose-dependent manner(P<0.05). CONCLUSION: Ginsenoside F2 protect HEK-293 cells against H_2O_2-induced oxidative stress through reducing intracellular ROS and MDA, as well as activating Nrf2/Keap1 signaling pathway and antioxidant enzymes.

Isolation and genomic characterization of lymphocytic choriomeningitis virus in ticks from northeastern China.

Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne arenavirus that is considered a neglected cause of neurologic diseases in humans. In this study, we described genomic characterization of newly isolated LCMVs in Haemaphysalis longicornis, Dermacentor nuttalli, Dermacentor silvarum and Ixodes persulcatus in Jilin Province, northeastern China. The complete sequences of the small (S) and large (L) segments of LCMVs in ticks contained 3,375 and 7,235-7,241 nucleotides, respectively. Sequence comparison showed 82.1%-86.0% identity of S segment with other lineage I strains at the nucleotide level and 91.2%-97.5% at the deduced amino acid level, while a lower identity was observed in the L segment at both nucleotide (75.4%-82.2%) and amino acid (82.4%-93.4%) levels. Phylogenetic analysis grouped the tick LCMVs together with the lineage I strains, but in an isolated cluster with a high bootstrap value. Bayesian analysis indicated that the molecular evolutionary rate was estimated to be 3.3 × 10-4 substitutions/site/year for the S segment and 6.3 × 10-4 substitutions/site/year for the L segment, and the time to most recent common ancestor was 1980 and 1970 years ago, respectively, showing that tick LCMVs were predicted to originate between 1970s and 1980s. A long evolutionary history and high prevalence of LCMV in H. longicornis were found compared to other tick species. This study represented the first report on isolation of LCMV in China, showing that LCMV is circulating among ticks in Jilin Province, but the role of ticks in the epidemiology of LCMV remains to be explored.

Physiochemical, texture properties, and the microstructure of set yogurt using whey protein-sodium tripolyphosphate aggregates as thickening agents.

BACKGROUND: Polymerized whey protein-sodium tripolyphosphate can be induced to gel in an acidic environment provided during fermentation. The variety of thickening agent has an influence on texture that is an essential aspect of yogurt quality affecting consumer preference. Similar to polysaccharide stabilizers, the cold gelation properties of whey proteins can improve the body texture of yogurt products. Polymerized whey protein-sodium tripolyphosphate could be a favorable and interesting thickening agent for making set yogurt. RESULTS: The effects of whey protein isolate (WPI), heat-treated whey protein-sodium tripolyphosphate (WPI-STPP), heat-treated WPI and pectin on the storage properties and microstructure of yogurt were investigated. All samples were analyzed for syneresis, pH, titratable acidity, viscosity, texture profile and microstructure during storage. The results showed that incorporating heat-treated WPI-STPP had a significant impact on syneresis (32.22 ± 0.60), viscosity (10 956.67 ± 962.1) and hardness (209.24 ± 12.48) (p < 0.05) with uniform body texture. CONCLUSION: Yogurt fermented with modified WPI-STPP had higher levels of protein and better hardness compared with yogurt using pectin. The microstructure was observed to be a uniform and denser, complicated network. Heat-treated WPI-STPP may be useful for improving yogurt texture. © 2016 Society of Chemical Industry.

Vaccination with Bivalent DNA Vaccine of α1-Giardin and CWP2 Delivered by Attenuated Salmonella typhimurium Reduces Trophozoites and Cysts in the Feces of Mice Infected with Giardia lamblia.

BACKGROUND: Giardia lamblia is one of the most common infectious protozoans in human that may cause diarrhea in travelers. Searching for antigens that induced effectively protective immunity has become a key point in the development of vaccine against giardiasis. METHODOLOGY/PRINCIPAL FINDINGS: Mice vaccinated with G. lamblia trophozozite-specific α1-giardin DNA vaccine delivered orally by attenuated Salmonella typhimurium SL7027 elicited 74.2% trophozoite reduction, but only 28% reduction in cyst shedding compared with PBS buffer control. Oral vaccination with Salmonella-delivered cyst-specific CWP2 DNA produced 89% reduction in cysts shedding in feces of vaccinated mice. Significantly, the mice vaccinated with Salmonella-delivered bivalent α1-giardin and CWP2 DNA vaccines produced significant reduction in both trophozoite (79%) and cyst (93%) in feces of vaccinated mice. This parasite reduction is associated with the strong local mucosal IgA secretion and the IgG2a-dominant systemic immune responses in vaccinated mice. CONCLUSIONS: The results demonstrate that bivalent vaccines targeting α1-giardin and CWP2 can protect mice against the colonization of Giardia trophozoite and block the transformation of cyst in host at the same time, and can be used to prevent Giardia infection and block the transmission of giardiasis.

The apoptotic effect and the plausible mechanism of microwave radiation on rat myocardial cells.

Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50, 100, 150, or 200 mW/cm(2) for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I-IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system.

Association of the FCN2 Gene Single Nucleotide Polymorphisms with Susceptibility to Pulmonary Tuberculosis.

Ficolin-2 (FCN2) is an innate immune pattern recognition molecule that can activate the complement pathway, opsonophagocytosis, and elimination of the pathogens. The present study aimed to investigate the association of the FCN2 gene single nucleotide polymorphisms (SNPs) with susceptibility to pulmonary tuberculosis (TB). A total of seven SNPs in exon 8 (+6359 C>T and +6424 G>T) and in the promoter region (-986 G>A, -602 G>A, -557 A>G, -64 A>C and -4 A>G) of the FCN2 gene were genotyped using the PCR amplification and DNA sequencing methods in the healthy controls group (n = 254) and the pulmonary TB group (n = 282). The correlation between SNPs and pulmonary TB was analyzed using the logistic regression method. The results showed that there were no significant differences in the distribution of allelic frequencies of seven SNPs between the pulmonary TB group and the healthy controls group. However, the frequency of the variant homozygous genotype (P = 0.037, -557 A>G; P = 0.038, -64 A>C; P = 0.024, +6424 G>T) in the TB group was significantly lower than the control group. After adjustment for age and gender, these variant homozygous genotypes were found to be recessive models in association with pulmonary TB. In addition, -64 A>C (P = 0.047) and +6424 G>T (P = 0.03) were found to be codominant models in association with pulmonary TB. There was strong linkage disequilibrium (r2 > 0.80, P < 0.0001) between 7 SNPs except the -602 G>A site. Therefore, -557 A>G, -64 A>C and +6424 G>T SNPs of the FCN2 gene were correlated with pulmonary TB, and may be protective factors for TB. This study provides a novel idea for the prevention and control of TB transmission from a genetics perspective.

A Rabbit Model of Acanthamoeba Keratitis That Better Reflects the Natural Human Infection.

Acanthamoeba species are ubiquitous, free-living protozoa that can invade the cornea and result in Acanthamoeba keratitis (AK), a painful progressive sight-threatening corneal disease. Disease progression in current animal models is too rapid to mimic AK in humans accurately. This study provides a novel method for establishing AK in rabbits and compared it with the conventional method with regard to pathogenesis and immune response in humans. The New Zealand white rabbits were randomly divided into two experimental groups (Groups A and B). Rabbits in the Group A (n = 14) received intrastromal injections of 1 × 10(4) /100 µL Acanthamoeba healyi trophozoites (conventional AK model). The Group B animals (n = 14) received microinjections of 1 × 10(4) /10 µL A. healyi trophozoites between the corneal epithelium and Bowman's layer, anterior to the corneal stroma (novel AK model). In addition, two rabbits were left untreated as normal controls. AK in the treated rabbits was evaluated clinically, histopathologically, and immunologically for 35 days. AK was successfully established in both the conventional and novel model groups. Compared with the Group A, AK in the Group B displayed an efficient immune response with less severe pathology. Moreover, the self-limiting but chronic nature of the infection in the Group B was strikingly similar to that of AK in humans. The novel animal model for AK described here more closely simulates the pathogenesis and immune response of Acanthamoeba corneal infection in humans than the animal models currently in use.

[Dynamic changes of serum antibody titer in a rabbit model of Acanthamoeba keratitis].

Ten healthy New Zealand white rabbits were randomly divided into two groups named as experiment group (n=8) and normal control group (n=2). Left eyes were for experiment, right eyes served as control. New Zealand rabbits were each injected by subconjunctival route with hydrocortisone for three days, and then Acanthamoeba keratitis was induced by intrastromal injection of live Acanthamoeba healyi trophozoites and cysts. Eyes in control group were injected with equivalent volume of physiological saline. Corneal lesions of rabbits were recorded every day after injection, etiological diagnosis was carried out by corneal scraping. Blood samples were examined for serum antibody titer by ELISA. Corneas were removed for pathological examination. Corneal scraping and corneal histopathologic examination proved that experiment eyes were infected by Acanthamoeba, and appeared typical manifestations and pathological changes of Acanthamoeba keratitis. Serum antibody titer raised continuously with infection time and reached the highest level (A450 value=2.2358) on the 28th days post-infection, then began to decline and remained higher level than the control until the rabbits were sacrificed. In control group, no significant change in antibody titer had taken place.