RESUMO
We propose a novel, to the best of our knowledge, approach to realizing instantaneous frequency measurement with ultrahigh measurement bandwidth, which utilizes three-channel photonic compressive sensing (CS) with sub-Nyquist pseudo-random binary sequences (PRBSs). In each CS channel, an alias frequency is recovered due to the sub-Nyquist property of the applied PRBS. A frequency identification algorithm is employed to determine the frequency of the signal under measurement according to the three alias frequencies. The proposed approach significantly reduces the bit rate of the applied PRBSs and the sampling rate required by the digitizers in CS. A proof-of-concept experiment for measuring frequency in the Ku band is demonstrated using PRBSs at 1â Gb/s and digitizers with a sampling rate of 250â MS/s.
RESUMO
A novel, to the best of our knowledge, photonics-assisted scheme for compressed sensing (CS) of sparse RF signals is proposed. An architecture with time-delayed dual-channel modulation of a pseudo-random binary sequence in combination with differential detection enables the generation of a rate-doubled bipolar random sequence, which largely increases the bandwidth of the CS system. In addition, the bipolarity of the random sequence ensures a zero-mean measurement matrix, which helps improve the signal recovery performance. Experimental results are presented to verify the performance improvement of the approach in comparison with the conventional single-ended photonic CS system.
RESUMO
Porcine teschovirus (PTV) comprises at least 13 genotypes (PTV 1-13). Here, the genotypes of field strains prevalent among pig populations in Hunan Province, China, were identified. Multiple PTV genotypes, including all genotypes except PTV 7 and 8, were found co-circulating in the pig populations, reflecting a high genetic diversity. Moreover, we identified nine novel PTV genotypes, provisionally designated as PTV 14-22. PTV 21-HuN41 and PTV 21-HuN42 were successfully isolated, and their nearly complete genomes were sequenced. Homology comparison of the polyprotein genes of PTV 21-HuN41-42 to those of other known PTVs revealed low identities, ranging from 70.1 to 71.9â% (nucleotide identity) and 75.4 to 77.6â% (amino acid identity). Moreover, PTV 21-HuN41-42 were identified as a novel teschovirus species (tentatively Teschovirus B), based on the analyses of phylogenetics and evolutionary divergence. The findings of this study are expected to greatly enrich our knowledge of PTV genotypes.
Assuntos
Infecções por Picornaviridae/veterinária , Doenças dos Suínos/virologia , Teschovirus/genética , Animais , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , China/epidemiologia , Evolução Molecular , Regulação Viral da Expressão Gênica , Genótipo , Filogenia , Infecções por Picornaviridae/virologia , Suínos , Doenças dos Suínos/epidemiologia , Teschovirus/isolamento & purificaçãoRESUMO
Porcine circovirus 2 (PCV2) has been widely prevailing in China since the first report in 2001, causing huge economic losses to the pig industry. In the present study, 674 samples were collected from 2006 to 2016 in Hunan province, and 62% were positive for PCV2. An increase was observed from 2006 to 2011 (72.1%-89.1%), and a decrease was observed from 2012 to 2016 (78.9%-36.8%). The prevalence of genotype PCV2a, PCV2b, and PCV2d was 0, 44.7% and 67%, respectively. During 2006-2007, PCV2b was the main genotype circulating in Hunan, while, in 2008, PCV2d became the predominant one. Coinfection with PCV2b and PCV2d was observed frequently, and the positive rates of coinfection ranged from 6.3% to 18.9% during 2006-2016. The complete genome was sequenced for 54 positive samples, and four were identified as PCV2b-1, 22 as PCV2b-2, four as PCV2d-1 and 24 as PCV2d-2, based on phylogenetic analysis of the complete genome and ORF2 region. Recombination analysis using the complete genome sequences of these isolates revealed a high recombination rate of 27.7% (17/54), and showed that recombination occurred mainly in the ORF1 region. This shows that the prevalence of PCV2 has clearly decreased in recent years and that PCV2d has become a predominant genotype since 2008. In addition, frequent recombination events were observed in the PCV2 isolates from Hunan, China.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/isolamento & purificação , Doenças dos Suínos/epidemiologia , Animais , China/epidemiologia , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/transmissão , Infecções por Circoviridae/virologia , Circovirus/classificação , Circovirus/genética , Coinfecção/epidemiologia , Coinfecção/veterinária , DNA Viral/genética , Variação Genética , Genoma Viral , Genótipo , Fases de Leitura Aberta , Prevalência , Recombinação Genética , Estudos Retrospectivos , Suínos/virologia , Doenças dos Suínos/virologia , Sequenciamento Completo do GenomaRESUMO
Toxoplasma gondii is one of the most important sources of foodborne diseases. In this study, the molecular prevalence and genotypes of T. gondii were investigated in pigs in Hunan province, China. A total of 339 brain tissue samples of pigs were collected from April 2015 to December 2017 in Hunan province and were used to detect the T. gondii B1 gene. Of these, 34 (10%; 95% confidence interval: 8.7-12.6) samples were tested positive for the T. gondii B1 gene. Positive samples were genotyped at 10 genetic markers (SAG1, SAG2 [5' + 3' SAG2, alter. SAG2], SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) using polymerase chain reaction-restriction fragment length polymorphism technology. Moreover, one sample was identified as genotype ToxoDB#10 (Type I), and another sample was suspected to be unusual genotype ToxoDB#61 that has never been reported in China. This study showed that T. gondii is prevalent in pigs in Hunan province, posing a food safety threat to the public health in the investigated areas. Our result has implications for better understanding the genetic diversity of T. gondii infections in animals in China.
RESUMO
Porcine sapeloviruses (PSVs) are widely distributed in pig populations; however, little information on their evolutionary history and the mechanisms driving their divergence is available. Therefore, in the present study, 241 fecal samples and 91 intestinal contents collected from pigs at 26 farms in Hunan, China, were tested for the presence of PSVs. The overall PSV positivity rate was 46.39â%, with a particularly high infection rate detected in nursery and fattening pigs. A total of 29 PSV strains (PSV-HuNs) were isolated, with these showing high genetic diversity based on phylogenetic and pairwise distance analyses of the capsid-protein gene sequences. Incongruence between phylognetic trees of the capsid-protein and 3CD regions indicated frequent recombination within the PSV-HuNs, and a putative recombinant hotspot near the 3' end of the P1 region was identified. Our results suggested that recombination played an important role in driving PSV genetic diversity and evolution.
Assuntos
Variação Genética , Infecções por Picornaviridae/veterinária , Picornaviridae/classificação , Picornaviridae/genética , Doenças dos Suínos/virologia , Animais , Proteínas do Capsídeo/genética , China/epidemiologia , Evolução Molecular , Fezes/virologia , Intestinos/virologia , Filogenia , Picornaviridae/isolamento & purificação , Infecções por Picornaviridae/epidemiologia , Infecções por Picornaviridae/virologia , Prevalência , Recombinação Genética , Análise de Sequência de DNA , Homologia de Sequência , Suínos , Doenças dos Suínos/epidemiologiaRESUMO
Outbreaks of diarrhea in piglets cause serious economic consequences in China. Diarrhetic fecal samples from 20 Hunan farm piglets were tested and found to be positive for porcine epidemic diarrhea virus (PEDV) by RT-PCR, although incubation with porcine kidney (PK-15) cells failed to produce infectious PEDV. Four porcine sapelovirus (PSV) strains (designated as PSV-HuNs) were isolated from four of the samples. Genomic sequence analysis revealed open reading frames encoding polyproteins of 2,331 (HuN1, 2 and 3) and 2,332 (HuN4) amino acids. Homology comparisons of the VP1 gene of the four Hunan strains with previously reported PSV strains revealed nucleotide sequence identities ranging from 74.2 to 98.6%, and deduced amino acid sequence identities from 79.5 to 98%. Phylogenetic analyses based on full-length and partial VP1 gene sequences showed that 3 of the PSV-HuN strains (HuN2, 3 and 4) clustered within a clade distinct from HuN1 as well as from all PSVs previously isolated in China, thereby showing that genetic diversity exists within Chinese PSVs. In addition, recombination analysis among PSVs indicates that a recombinant (HuN2 strain) exist in China.
Assuntos
Infecções por Coronavirus/veterinária , Fezes/virologia , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Proteínas do Capsídeo/genética , China/epidemiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Surtos de Doenças , Variação Genética , Genoma Viral , Filogenia , Recombinação Genética , Análise de Sequência de DNA , Suínos , Doenças dos Suínos/epidemiologiaRESUMO
Astroviruses (AstVs) can infect a variety of hosts, including mammalian and avian species, and are commonly associated with enteric infections. Recently, mammalian AstVs have been linked to extra-intestinal manifestations, including neurologic disorders in humans, cattle and minks, demonstrating zoonotic potential. So far, five porcine AstV (PAstV) genotypes have been identified, with PAstV1, PAstV2, PAstV3 and PAstV5 implicated in cross-species transmission. Our knowledge about PAstV epidemiology in China is still limited. In this study, two duplex differential RT-PCR assays were developed to investigate the distribution and prevalence of PAstV1, PAstV2, PAstV4 and PAstV5. Two hundred eighteen samples were collected from 33 farms and pigs with known diarrhea status in nine regions of Hunan province in China. Specifically, 126 small intestines, 51 fecal swabs, 20 lungs, 19 spleens and two kidneys were obtained. PAstVs were detected in all nine regions and in 81.8% (27/33) of the pig farms investigated. The overall prevalence of PAstV was 46.3% (101/218), with PAstV5 as the predominant type, with a positive rate of 24.8% (54/218). The prevalence of PAstV4, PAstV1 and PAstV2 was 16.1% (35/218), 14.7% (32/218) and 10.1% (22/218), respectively. Besides being present in intestines and fecal swabs, PAstV RNA was also detected in lungs, spleens and kidneys. Sequencing revealed a high level of genetic divergence within each genotype, and a higher positive rate of PAstV5 was associated with pigs with diarrhea compared to pigs without diarrhea. This study revealed for the first time that PAstV4 is circulating in China, and that PAstV5 is the dominant genotype in pig herds in Hunan province in China.
Assuntos
Infecções por Astroviridae/veterinária , Mamastrovirus/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Infecções por Astroviridae/epidemiologia , Infecções por Astroviridae/transmissão , Infecções por Astroviridae/virologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , China/epidemiologia , Fezes/virologia , Genótipo , Humanos , Rim/virologia , Pulmão/virologia , Mamastrovirus/classificação , Mamastrovirus/genética , Vison/virologia , Filogenia , Baço/virologia , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissãoRESUMO
Toxoplasma gondii infections are prevalent in animals and humans worldwide. Although the prevalence of T. gondii has been reported in many animals in China, little is known of T. gondii infection in sows. Antibodies to T. gondii in sows in Hunan province, subtropical China, were examined using indirect hemagglutination test (IHAT). Overall, 31.3% (373/1191) of the examined sows were seropositive for T. gondii. Among 11 representative regions of Hunan province, the seroprevalence ranged from 14.8% to 45.1%. In addition, the T. gondii seroprevalence was higher in summer (37.4%) and autumn (34.9%) than in spring (24.6%) and winter (23.9%). Regarding different antibody titers, the seroprevalence ranged from 1.8% (titer ≥ 1: 1024) to 17.4% (titer = 1:64). The findings of the present investigation revealed the high seroprevalence of T. gondii in sows in Hunan province, China, which poses a potential risk for T. gondii infection in humans and animals in this province. Therefore, effective measures should be taken to prevent and control toxoplasmosis of pigs in this province. This is the first report of the comprehensive survey of T. gondii seroprevalence in sows in Hunan Province, subtropical China.
Assuntos
Doenças dos Suínos/diagnóstico , Doenças dos Suínos/epidemiologia , Toxoplasmose Animal/diagnóstico , Toxoplasmose Animal/epidemiologia , Animais , China/epidemiologia , Feminino , Prevalência , Fatores de Risco , Testes Sorológicos , Suínos , Doenças dos Suínos/imunologia , Toxoplasmose Animal/imunologiaRESUMO
Chlamydia spp. are Gram-negative obligate intracellular bacteria, which are responsible for significant public health problems in humans and have major economic impact on animals. In the present study, the seroprevalence of Chlamydia infection in sows in Hunan province, subtropical China, was examined using indirect hemagglutination assay (IHA). Antibodies to Chlamydia were detected in 747 of 1,191 (62.7%, 95% CI 60-65.5) serum samples (IHA titer ≥ 1:16). The Chlamydia seroprevalence ranged from 35% (95% CI 25.7-44.4) to 77.1% (95% CI 69.1-85.2) among different regions in Hunan province, and the differences were statistically significant (P < 0.01). In addition, the seroprevalence of Chlamydia infection in sows was higher in summer (75.7%, 95% CI 71.3-80) and spring (63.2%, 95% CI 57.5-68.8) than in autumn (56.9%, 95% CI 51.5-62.3) and winter (48.6%, 95% CI 42-55.3), and the differences were statistically significant (P < 0.01). The results of the present investigation indicated the high seroprevalence of Chlamydia infection in sows in Hunan province, subtropical China, which poses a potential risk for human infection with Chlamydia in this province. This is the first report of Chlamydia seroprevalence in sows over the last two decades in Hunan province, subtropical China.
Assuntos
Infecções por Chlamydia/veterinária , Doenças dos Suínos/epidemiologia , Animais , Anticorpos Antibacterianos/sangue , China/epidemiologia , Chlamydia/imunologia , Infecções por Chlamydia/epidemiologia , Infecções por Chlamydia/microbiologia , Clima , Feminino , Humanos , Estações do Ano , Estudos Soroepidemiológicos , Suínos , Doenças dos Suínos/sangue , Doenças dos Suínos/microbiologiaRESUMO
Phase I trials inform on the initial safety profile of a new molecule and impact whether further development is pursued or not. Understanding the effect of non-pharmacological factors on the variability of routine safety parameters could improve decision making in these early clinical trials, helping to separate signals related to the new molecule from background "noise." To understand the impact of non-pharmacological factors on routine safety parameters, we evaluated pooled safety data from over 1000 healthy participants treated with placebo in phase I trials between 2009 and 2018. The phase I participants were predominantly men, less than or equal to 50 years, White, and non-Hispanic; and approximately an equal proportion had body mass index in the normal and overweight/obese range. Following administration of placebo, vital signs, electrocardiogram, and laboratory parameters remained near predose baseline values. Large changes from baseline were observed for many safety parameters, but these occurred in a relatively small number of participants. At least one adverse event (AE) occurred in 49.7% of participants receiving placebo in single ascending dose (SAD) studies and in 72.4% of participants receiving placebo in multiple ascending dose (MAD) studies, with headache being the most commonly reported AE (18.7% in SAD and 28.3% in MAD studies). Overall, these analyses are consistent with non-pharmacological factors having a small impact on routine safety parameters in a phase I trial. The provided supplemental data may be used to contextualize the magnitude and frequency of abnormal safety values and AEs observed in phase I trials.
Assuntos
Eletrocardiografia , Obesidade , Masculino , Humanos , Feminino , Voluntários Saudáveis , Testes de Coagulação Sanguínea , Índice de Massa CorporalRESUMO
The incidence of type 2 diabetes mellitus (T2DM) induced by obesity is rapidly increasing. Although there are many synthetic drugs for treating T2DM, they have various side effects. Here, we report that miR8175, a plant miRNA from burdock root, has effective antidiabetic activity. After administration of burdock decoction or synthetic miR8175 by gavage, both burdock decoction and miR8175 can significantly improve the impaired glucose metabolism of diabetic mice induced by a high-fat diet (HFD). Our results demonstrate that burdock decoction and miR8175 enhance the insulin sensitivity of the hepatic insulin signaling pathway by targeting Ptprf and Ptp1b, which may be the reason for the improvement in metabolism. This study provides a theoretical basis for the main active component and molecular mechanism of burdock to improve insulin resistance. And the study also suggests that plant miRNA may be an indispensable nutrient for maintaining human health.
RESUMO
The seroprevalence of porcine cytomegalovirus (PCMV) and sapovirus (SaV) infections in pigs was investigated in Hunan province, China, between May 2005 and October 2010. A total of 500 pig serum samples collected from 10 representative administrative regions in Hunan province were evaluated for antibodies against PCMV and SaV using enzyme-linked immunosorbent assay (ELISA). The overall seroprevalence of porcine cytomegalovirus and sapovirus in pigs was 96.40% (482/500) and 63.40% (317/500), and the seropositivity of 10 herds we surveyed varied, ranging from 94.74% to 98.48% and 56.36% to 72.50%, respectively. The highest prevalence was found in breeding sows (96.67% for PCMV and 83.33% for SaVs). The results of the present survey indicated that infections with porcine cytomegalovirus and sapovirus are highly prevalent in pigs in Hunan province, China.
Assuntos
Anticorpos Antivirais/sangue , Infecções por Caliciviridae/veterinária , Infecções por Citomegalovirus/veterinária , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/virologia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , China/epidemiologia , Citomegalovirus/imunologia , Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/virologia , Ensaio de Imunoadsorção Enzimática , Sapovirus/imunologia , Estudos Soroepidemiológicos , SuínosRESUMO
The prevalence of porcine sapovirus infection in weanling pigs was investigated in Hunan Province, China, between August 2006 and October 2007. A total of 153 diarrheic fecal samples from ten intensive pig farms from ten representative administrative regions in Hunan province were examined for porcine sapoviruses using RT-PCR. Twenty-two of 153 (14.37 %) samples were found to contain porcine sapoviruses. Phylogenetic analysis showed that all the porcine sapovirus isolates in Hunan Province belonged to the porcine sapovirus genogroup III. The results of the present investigation have implications for the control of porcine sapovirus infection in pigs in Hunan Province, China.
Assuntos
Infecções por Caliciviridae/veterinária , Gastroenterite/veterinária , RNA Viral/genética , Sapovirus/genética , Doenças dos Suínos/epidemiologia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , China/epidemiologia , Fezes/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Dados de Sequência Molecular , Filogenia , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Sapovirus/isolamento & purificação , Análise de Sequência de RNA/veterinária , Suínos , Doenças dos Suínos/virologiaRESUMO
Neospora caninum is a protozoan parasite which can infect many mammals and birds with a worldwide distribution. However, no molecular data are available about the occurrence of N. caninum in pigs. In this study, the serological and molecular prevalence of N. caninum infection in farmed pigs were investigated in Hunan province, China, between January 2017 and December 2018. A total of 1,500 serum samples collected from 10 herds in Hunan province were evaluated using a competitive-inhibition enzyme-linked immunoassay assay (cELISA). The overall seroprevalence of N. caninum in the examined pigs was 1.9%. The seroprevalence of N. caninum ranged from 0.3% to 4.6% among different regions in Hunan province of China (p < .05). DNA was extracted from brain samples, and the Nc-5 gene and ITS-1 region were amplified and then sequenced. Three (0.5%) of the examined 600 brain tissues were found to contain N. caninum DNA. Our phylogenetic analyses indicated that N. caninum samples were classified into two distinct groups. Although the prevalence is low within the pig groups investigated, our results revealed the emergence of N. caninum infection in pigs in China. The finding of the present study provides molecular evidence that the pigs are the natural intermediate host of N. caninum and may have major epidemiological importance.
Assuntos
Anticorpos Antiprotozoários/sangue , Coccidiose/veterinária , Diarreia/veterinária , Neospora/genética , Doenças dos Suínos/virologia , Animais , China/epidemiologia , Coccidiose/epidemiologia , Coccidiose/parasitologia , Diarreia/epidemiologia , Diarreia/virologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Neospora/imunologia , Neospora/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase/veterinária , Estudos Soroepidemiológicos , Suínos , Doenças dos Suínos/epidemiologiaRESUMO
Two commercial porcine reproductive and respiratory syndrome virus (PRRSV) antibody ELISA kits (IDEXX and LSI) are currently in extensive use. To determine which kit is more suitable for the evaluation of HP-PRRSV vaccine efficacy, the two kits were used to test 546 serum samples. The agreement between the results was unsatisfactory, with a kappa statistic of 0.681 and a linear correlation coefficient of 0.665. In tests of samples from experimentally vaccinated and PRRSV-negative herds, IDEXX-ELISA identified antibody-positive conversion earlier and showed a higher specificity compared to LSI-ELISA. The serological profile obtained by neutralization testing was closer to that obtained by IDEXX-ELISA than by LSI-ELISA in the late immunization period. The findings reveal that IDEXX-ELISA is the more suitable for the evaluation of antibody response to HP-PRRSV vaccine and for guiding vaccination strategies.
Assuntos
Anticorpos Antivirais , Síndrome Respiratória e Reprodutiva Suína/imunologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/sangue , Ensaio de Imunoadsorção Enzimática , Testes de Neutralização/veterinária , Síndrome Respiratória e Reprodutiva Suína/sangue , Síndrome Respiratória e Reprodutiva Suína/prevenção & controle , Suínos , Vacinação/veterináriaRESUMO
To simultaneously impart excellent biological activity and antibacterial function to titanium-based metal materials, rubidium-doped titanium surfaces were prepared via alkali heat treatment, subsequent hydrothermal treatment and final heat treatment. The alkali heat treatment was employed to fabricate an amorphous sodium titanate hydrogel layer on titanium substrates. Thereafter, rubidium was introduced through the hydrothermal process. After final heat treatment, crystallized rubidium titanate and sodium titanate were obtained on titanium surfaces. The viability of MC3T3-E1 cells was inhibited on rubidium-doped titanium surfaces for short-term (day 1). With prolonged duration, the viability and alkali phosphatase (ALP) activity were comparable for various surfaces with different amounts of rubidium (day 5). With further increased culture duration, the collagen synthesis (day 10) and in vitro mineralization of osteoblasts were found to be significantly enhanced on rubidium-doped titanium surfaces. The Rb-doped Ti surfaces showed antibacterial capacity against Staphylococcus aureus at both 12 and 24 h. The results indicate that doping rubidium into titanium surfaces could simultaneously endow materials with favorable osteogenic and antibacterial capacity.
Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Rubídio/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Titânio/farmacologia , Células 3T3 , Fosfatase Alcalina/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Temperatura Alta , Teste de Materiais , Camundongos , Testes de Sensibilidade Microbiana , Osseointegração , Osteoblastos/citologia , Osteogênese , Óxidos/química , Propriedades de Superfície , Titânio/químicaRESUMO
Toxoplasma gondii infection is prevalent in humans and animals worldwide. In the present study, a total of 612 serum samples were examined using indirect hemagglutination test (IHAT) for T. gondii infection. Antibodies to T. gondii were detected in 49 (8.0%, confidence interval [95% CI]: 5.9-10.2) serum samples (IHA titer ≥1:16). The T. gondii seroprevalence ranged from 4.4% (95% CI: 0-10.5) to 14.3% (95% CI: 0-40.2) among different regions in Hunan province of subtropical China. The highest seroprevalence was found in breeding sows (18.8%). The T. gondii seroprevalence was higher in winter (18.3%, 95% CI: 8.5-28.1) and spring (10.9%, 95% CI: 5.7-16.1) than in summer (6.4%, 95% CI: 2.8-10.1) and autumn (4.9%, 95% CI: 2.2-7.7), and the differences were statistically significant excepting summer. In addition, developmental stage and season were identified as risk factors for T. gondii infection. Our findings revealed the seroprevalence of T. gondii in growth stages of pigs in the Hunan province of subtropical China, indicating that it may cause public health and economic problems. To our knowledge, this is the first report of the comprehensive survey of T. gondii seroprevalence in pigs in the Hunan province of subtropical China.
Assuntos
Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Toxoplasmose Animal/epidemiologia , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/sangue , China/epidemiologia , Regulação Viral da Expressão Gênica , Humanos , Fatores de Risco , Estudos Soroepidemiológicos , Suínos , Toxoplasma/imunologia , Proteínas Virais/genética , Proteínas Virais/metabolismo , ZoonosesRESUMO
Streptococcus suis is a zoonotic pathogen that harbors anti-oxidative stress genes, which have been reported to be associated with virulence. Serial passage has been widely used to obtain phenotypic variant strains to investigate the functions of important genes. In the present study, S. suis serotype 9 strain DN13 was serially passaged in mice 30 times. The virulence of a single colony from passage 10 (SS9-P10) was found to increase by at least 140-fold as indicated by LD50 values, and the increased virulence was stable for single colonies from passage 20 (SS0-P20) and 30 (SS0-P30). Compared to the parental strain, the mouse-adapted strains were more tolerant to oxidative and high temperature stress. Genome-wide analysis of nucleotide variations found that reverse mutations occurred in seven genes, as indicated by BLAST analysis. Three of the reverse mutation genes or their homologs in other bacteria were reported to be virulence-associated, including ideSsuis in S. suis, a homolog of malR of Streptococcus pneumoniae, and a homolog of the prepilin peptidase-encoding gene in Legionella pneumophila. However, these genes were not involved in the stress response. Another gene, srtR (stress response transcriptional regulator), encoding an XRE family transcriptional regulator, which had an internal stop in the parental strain, was functionally restored in the adapted strains. Further analysis of DN13 and SS9-P10-background srtR-knock-out and complementing strains supported the contribution of this gene to stress tolerance in vitro and virulence in mice. srtR and its homologs are widely distributed in Gram-positive bacteria including several important human pathogens such as Enterococcus faecium and Clostridioides difficile, indicating similar functions in these bacteria. Taken together, our study identified the first member of the XRE family of transcriptional regulators that is involved in stress tolerance and virulence. It also provides insight into the mechanism of enhanced virulence after serial passage in experimental animals.
Assuntos
Adaptação Fisiológica , Tolerância a Medicamentos , Regulação Bacteriana da Expressão Gênica , Oxidantes/toxicidade , Streptococcus suis/efeitos dos fármacos , Streptococcus suis/patogenicidade , Fatores de Transcrição/metabolismo , Animais , Análise Mutacional de DNA , Modelos Animais de Doenças , Resposta ao Choque Térmico , Dose Letal Mediana , Camundongos , Estresse Oxidativo , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/patologia , Streptococcus suis/genética , Estresse Fisiológico , Virulência , Sequenciamento Completo do GenomaRESUMO
Environmental exposure is considered to be responsible for nontuberculous mycobacterial infections in humans. To facilitate the isolation of mycobacteria from soil, Middlebrook 7H10 agar was optimized as an enhanced selective medium by increasing the concentration of malachite green. A series of modified Middlebrook 7H10 agar media with malachite green concentrations ranging from 2.5 to 2500 mg/L was evaluated using 20 soil samples decontaminated with 3% sodium dodecyl sulfate plus 2% NaOH for 30 min. Among these modified Middlebrook 7H10 media, the medium with malachite green at a concentration of 250 mg/L, i.e., at the same concentration as in Löwenstein-Jensen medium, was the most effective in terms of the number of plates with mycobacterial growth. This medium was further evaluated with 116 soil samples. The results showed that 87.1% (101/116) of the samples produced mycobacterial growth, and 15 samples (12.9%) produced no mycobacterial growth. Of the plates inoculated with the soil samples, each in duplicate, 5.2% (12/232) showed late contamination. In total, 19 mycobacterial species were isolated, including seven (36.8%) rapidly growing mycobacteria and 12 (63.2%) slowly growing mycobacteria. Our results demonstrate that the modified Middlebrook 7H10 agar with 250 mg/L malachite green is useful for the primary isolation of nontuberculous mycobacteria from soil.