Potential biomarkers for evaluating the BCG vaccination response based on humoral immunity.

Background: The current prophylactic tuberculosis vaccine Bacille Calmette-Guérin (BCG), was derived in the 1920s, but the humoral immune responses induced by BCG vaccination have not been fully elucidated to date. In this study, our aim was to reveal the profiles of antibody responses induced by BCG vaccination in adults and identify the potential biomarkers for evaluating the BCG vaccination response. Methods: Proteome microarrays were performed to reveal the serum profiles of antibody responses induced by BCG vaccination in adults. ELISA was used to validate the potential biomarkers in validation cohort (79 healthy controls and 58 BCG-vaccinated subjects). Then combined panel was established by logistic regression analysis based on OD values of potential biomarkers. Results: Multiple antigens elicited stronger serum IgG or IgM antibody responses in BCG vaccinated subjects than healthy subjects at 12 weeks post BCG vaccination; among the antigens, Rv0060, Rv2026c and Rv3379c were further verified using 137 serum samples and presented the moderate performance in assessment of the BCG vaccination response by receiver operating characteristic analysis. Furthermore, a combined panel exhibited an improved AUC of 0.923, and the sensitivity and specificity were 77.59 % and 91.14 %, respectively. In addition, the antibody response against Rv0060, Rv2026c and Rv3379c was related to the clinical background to a certain extent. Conclusions: The novel antigens identified in our study could offer better knowledge towards developing a more efficacious vaccine based on humoral immune responses, and they could be potential biomarkers in assessments of BCG vaccination responses.

Omics analysis revealed the intestinal toxicity induced by aflatoxin B1 and aflatoxin M1.

Aflatoxin B1 (AFB1), a common mycotoxin, can occur in agricultural products. As a metabolite of AFB1, aflatoxin M1 (AFM1) mainly exist in dairy products. These two mycotoxins threaten human health, although it is unclear how they affect the function of the intestinal barrier. In this study, mice were exposed to AFB1 (0.3 mg/kg body b.w.) and AFM1(3.0 mg/kg b.w.) either individually or in combination for 28 days to explore the main differentially expressed proteins (DEPs) and the associated enriched pathways. These findings were preliminarily verified by the transcriptomic and proteomic analyses in differentiated Caco-2 cells. The results revealed that AFB1 and AFM1 exposure in mice disrupted the function of the intestinal barrier, and the combined toxicity was greater than that of each toxin alone. Further proteomic analysis in mice demonstrated that the mechanisms underlying these differences could be explained as follows: (i) lipid metabolism was enriched by AFB1-induced DEPs. (ii) protein export pathway was stimulated by AFM1-induced DEPs. (iii) cell metabolic ability was inhibited (as evidenced by changes in UDP-GT1, UDP-GT2, and Gatm6), apoptosis was induced (MAP4K3), and epithelial cell integrity was disrupted (Claudin7 and IQGAP2), resulting in more extensive intestinal damage after combined treatment. In conclusion, the hazardous impact of co-exposure to AFB1 and AFM1 from proteomic perspectives was demonstrated in the present study.

SUE4, a novel PIN1-interacting membrane protein, regulates acropetal auxin transport in response to sulfur deficiency.

Sulfur (S) is an essential macronutrient for plants and a signaling molecule in abiotic stress responses. It is known that S availability modulates root system architecture; however, the underlying molecular mechanisms are largely unknown. We previously reported an Arabidopsis gain-of-function mutant sulfate utilization efficiency4 (sue4) that could tolerate S deficiency during germination and early seedling growth with faster primary root elongation. Here, we report that SUE4, a novel plasma membrane-localized protein, interacts with the polar auxin transporter PIN1, resulting in reduced PIN1 protein levels and thus decreasing auxin transport to the root tips, which promotes primary root elongation. Moreover, SUE4 is induced by sulfate deficiency, consistent with its role in root elongation. Further analyses showed that the SUE4-PIN1 interaction decreased PIN1 levels, possibly through 26 S proteasome-mediated degradation. Taken together, our finding of SUE4-mediated root elongation is consistent with root adaptation to highly mobile sulfate in soil, thus revealing a novel component in the adaptive response of roots to S deficiency.

Progress on nutritional assessment and nutritional support for liver transplant recipients / 器官移植

Patients with end-stage liver disease after liver transplantation constantly suffer from malnutrition due to primary diseases and transplantation-related factors. Malnutrition will worsen clinical condition of the patients, increase the incidence of complication, length of hospital stay and medical expense after transplantation, and lower the survival rate. Sufficient nutritional support at all stages of liver transplantation is of significance. Accurate assessment of nutritional status and timely intervention are prerequisites for perioperative nutritional treatment in liver transplantation. In this article, the latest nutritional risk screening indexes and evaluation tools, nutritional support methods and other perioperative nutritional intervention measures for liver transplantation were reviewed, aiming to deepen the understanding and cognition of perioperative nutritional therapy for liver transplantation and provide reference for improving nutritional status and clinical prognosis of liver transplant recipients.

Analysis of tuberculosis epidemiological characteristics and drug resistance among the floating population in Beijing in 2019 / 中华流行病学杂志

Objective: To analyze the epidemic characteristics and drug resistance of pulmonary tuberculosis among the floating population in Beijing and to provide a scientific basis for formulating strategies for the prevention and control of tuberculosis among the floating population. Methods: Data of tuberculosis patients who were positive for Mycobacterium tuberculosis culture was collected from 16 districts and one municipal institution of tuberculosis control and prevention in Beijing in 2019. The strain samples were tested for drug sensitivity by the proportional method. According to household registration location, patients were divided into the floating population and Beijing registration. SPSS 19.0 software analyzed tuberculosis patients' epidemic characteristics and drug resistance in the floating population. Results: In 2019, there were 1 171 culture-positive tuberculosis patients in Beijing, among the floating population, 593 (50.64%) patients were identified, with a male-to-female sex ratio of 2.2∶1 (409∶184). Compared to patients under household registration as Beijing residents, a higher proportion of young adults aged 20-39 years (65.09%,386/593) were noticed, with 55.65% (330/593) reported from the urban areas and 96.80% (574/593) were reported the first time. The differences were statistically significant (all P<0.05). After completing the drug sensitivity test, 37 cases were with multiple drug-resistant tuberculosis, accounting for 6.24% (37/593). The rates of isoniazid resistance (42.11%,8/19) and multidrug resistance (21.05%,4/19) in floating population patients after retreatment were significantly higher than those in newly treated patients (11.67%, 67/574 and 5.75%, 33/574), and the differences were statistically significant (all P<0.05). Conclusions: Most patients with tuberculosis in the floating population in Beijing in 2019 were young males aged 20-39 years. The reporting areas were urban areas and the newly treated patients mainly. The patients with tuberculosis in the re-treated floating population were more likely to suffer from multidrug and drug resistance, which should be taken as the key population for prevention and control.

Tuberculosis relapse is more common than reinfection in Beijing, China.

BACKGROUND: Recurrent tuberculosis (TB) is a major health problem in countries with a high TB burden. It is very necessary to elucidate the situation of recurrent TB in Beijing, capital of China. OBJECTIVE: To determine the proportion of recurrent tuberculosis (TB) cases and to identify relapsed or reinfected cases, as well as risk factors associated with recurrence in Beijing. METHODS: We conducted a retrospective study that included all TB cases in Beijing that were successfully treated from 2013 to 2015. Recurrence due to relapse or reinfection was determined using the variable number of tandem repeats (VNTR) method. Risk factors associated with recurrence were analysed. RESULTS: Tuberculosis recurred in 275 of the 4043 successfully treated TB patients, giving a recurrence rate of 6.8% (275/4043). 190 of the 275 cases were culture positive in both instances, and genotyping results for both episodes were available for 58 of these patients. The cultured isolates from 40 of the 58 recurrent cases (69%) had identical genotypic patterns in both episodes, indicating a relapse. 31% (18/58) had different genotypes, indicating reinfection by a new strain and suggested recent transmission. Those people in the 30-59 age group (p < .001), and those retreated for pulmonary TB (p < .001) were more likely to have TB recurrence. CONCLUSION: Our results indicate that relapse was more common than reinfection in recurrent TB cases in Beijing from 2013 to 2015. Age and retreatment were found to be risk factors for TB recurrence.

VHL-HIF-2α axis-induced SMYD3 upregulation drives renal cell carcinoma progression via direct trans-activation of EGFR.

It has been well established that the von Hippel-Lindau/hypoxia-inducible factor α (VHL-HIFα) axis and epidermal growth factor receptor (EGFR) signaling pathway play a critical role in the pathogenesis and progression of renal cell carcinoma (RCC). However, few studies have addressed the relationship between the two oncogenic drivers in RCC. SET and MYND domain-containing protein 3 (SMYD3) is a histone methyltransferase involved in gene transcription and oncogenesis, but its expression and function in RCC remain unclear. In the present study, we found that SMYD3 expression was significantly elevated in RCC tumors and correlated with advanced tumor stage, histological and nuclear grade, and shorter survival. Depletion of SMYD3 inhibited RCC cell proliferation, colony numbers, and xenograft tumor formation, while promoted apoptosis. Mechanistically, SMYD3 cooperates with SP1 to transcriptionally promote EGFR expression, amplifying its downstream signaling activity. TCGA data analyses revealed a significantly increased SMYD3 expression in primary RCC tumors carrying the loss-of-function VHL mutations. We further showed that HIF-2α can directly bind to the SMYD3 promoter and subsequently induced SMYD3 transcription and expression. Taken together, we identify the VHL/HIF-2α/SMYD3 signaling cascade-mediated EGFR hyperactivity through which SMYD3 promotes RCC progression. Our study suggests that SMYD3 is a potential therapeutic target and prognostic factor in RCC.

Airborne host-plant manipulation by whiteflies via an inducible blend of plant volatiles.

The whitefly Bemisia tabaci is one of the world's most important invasive crop pests, possibly because it manipulates plant defense signaling. Upon infestation by whiteflies, plants mobilize salicylic acid (SA)-dependent defenses, which mainly target pathogens. In contrast, jasmonic acid (JA)-dependent defenses are gradually suppressed in whitefly-infested plants. The down-regulation of JA defenses make plants more susceptible to insects, including whiteflies. Here, we report that this host-plant manipulation extends to neighboring plants via airborne signals. Plants respond to insect attack with the release of a blend of inducible volatiles. Perception of these volatiles by neighboring plants usually primes them to prepare for an imminent attack. Here, however, we show that whitefly-induced tomato plant volatiles prime SA-dependent defenses and suppress JA-dependent defenses, thus rendering neighboring tomato plants more susceptible to whiteflies. Experiments with volatiles from caterpillar-damaged and pathogen-infected plants, as well as with synthetic volatiles, confirm that whiteflies modify the quality of neighboring plants for their offspring via whitefly-inducible plant volatiles.

Screening of Serum Biomarkers for Distinguishing between Latent and Active Tuberculosis Using Proteome Microarray.

OBJECTIVE: To identify potential serum biomarkers for distinguishing between latent tuberculosis infection (LTBI) and active tuberculosis (TB). METHODS: A proteome microarray containing 4,262 antigens was used for screening serum biomarkers of 40 serum samples from patients with LTBI and active TB at the systems level. The interaction network and functional classification of differentially expressed antigens were analyzed using STRING 10.0 and the TB database, respectively. Enzyme-linked immunosorbent assays (ELISA) were used to validate candidate antigens further using 279 samples. The diagnostic performances of candidate antigens were evaluated by receiver operating characteristic curve (ROC) analysis. Both antigen combination and logistic regression analysis were used to improve diagnostic ability. RESULTS: Microarray results showed that levels of 152 Mycobacterium tuberculosis (Mtb)-antigen- specific IgG were significantly higher in active TB patients than in LTBI patients (P < 0.05), and these differentially expressed antigens showed stronger associations with each other and were involved in various biological processes. Eleven candidate antigens were further validated using ELISA and showed consistent results in microarray analysis. ROC analysis showed that antigens Rv2031c, Rv1408, and Rv2421c had higher areas under the curve (AUCs) of 0.8520, 0.8152, and 0.7970, respectively. In addition, both antigen combination and logistic regression analysis improved the diagnostic ability. CONCLUSION: Several antigens have the potential to serve as serum biomarkers for discrimination between LTBI and active TB.

Electroacupuncture Potentiates Cannabinoid Receptor-Mediated Descending Inhibitory Control in a Mouse Model of Knee Osteoarthritis.

Knee osteoarthritis (KOA) is a highly prevalent, chronic joint disorder, which can lead to chronic pain. Although electroacupuncture (EA) is effective in relieving chronic pain in the clinic, the involved mechanisms remain unclear. Reduced diffuse noxius inhibitory controls (DNIC) function is associated with chronic pain and may be related to the action of endocannabinoids. In the present study, we determined whether EA may potentiate cannabinoid receptor-mediated descending inhibitory control and inhibit chronic pain in a mouse model of KOA. We found that the optimized parameters of EA inhibiting chronic pain were the low frequency and high intensity (2 Hz + 1 mA). EA reversed the reduced expression of CB1 receptors and the 2-arachidonoylglycerol (2-AG) level in the midbrain in chronic pain. Microinjection of the CB1 receptor antagonist AM251 into the ventrolateral periaqueductal gray (vlPAG) can reversed the EA effect on pain hypersensitivity and DNIC function. In addition, CB1 receptors on GABAergic but not glutamatergic neurons are involved in the EA effect on DNIC function and descending inhibitory control of 5-HT in the medulla, thus inhibiting chronic pain. Our data suggest that endocannabinoid (2-AG)-CB1R-GABA-5-HT may be a novel signaling pathway involved in the effect of EA improving DNIC function and inhibiting chronic pain.

Identification of PTCH1-3'-UTR regulated lncRNAs associated with competing endogenous RNA networks in non-small cell lung cancer cell line / 复旦学报（医学版）

Objective To investgate the effect of PTCH1-3'-UTR on the expression of long noncoding RNAs (lncRNAs) and analyze regulatory networks so as to indicate the function of PTCH1-3'-UTR.Methods We screened PTCH1-3'-UTR regulated lncRNAs in non-small cell lung cancer (NSCLC) by using microarray,and validated the expression by qPCR.To explore the potential mechanisms of these lncRNAs underlying NSCLC progression,we performed GO and KEGG pathway analysis of the dysregulated lncRNAs.We also conducted a bioinformatic analysis in TCGA database to identify the association of PTCH1-3'-UTR regulated lncRNAs and the overall survival of NSCLC patients.Results The expression of seven PTCH1-3'-UTR up-regulated lncRNAs (LOC100507547,FAM41C,DOCK4-AS1,AC009305.1,KLF7-IT1,RP11-749H20.1,LINC01511) were validated by qPCR.The GO and KEGG pathway analysis of the dysregulated lncRNAs indicated that a series of biological progresses were involved in the function of PTCH1-3'-UTR regulated lncRNAs,including transcription,signal transduction,protein transport and translational elongation,and several pathways,such as calcium signaling pathway,Jak-STAT signaling pathway,p53 signaling pathway and insulin signaling pathway.Among the lncRNAs regulating PTCH1-3'-UTR,6 were shown to be associated with the overall survival of NSCLC patients.High expression of lncRNA-CDKN2BAS and FAM66D related to the probability of lower survival,while high expression of lncRNA-LINC00240,LOC400027,ABCC6P2 and FLJ10038 might have a higher probability of survival.Conclusions The study would provide an insight of the function of PTCH1-3'-UTR,and PTCH1-3'-UTR dysregulated lncRNAs may be potential prognostic biomarkers for NSCLC.

Screening of Serum Biomarkers for Distinguishing between Latent and Active Tuberculosis Using Proteome Microarray / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To identify potential serum biomarkers for distinguishing between latent tuberculosis infection (LTBI) and active tuberculosis (TB).</p><p><b>METHODS</b>A proteome microarray containing 4,262 antigens was used for screening serum biomarkers of 40 serum samples from patients with LTBI and active TB at the systems level. The interaction network and functional classification of differentially expressed antigens were analyzed using STRING 10.0 and the TB database, respectively. Enzyme-linked immunosorbent assays (ELISA) were used to validate candidate antigens further using 279 samples. The diagnostic performances of candidate antigens were evaluated by receiver operating characteristic curve (ROC) analysis. Both antigen combination and logistic regression analysis were used to improve diagnostic ability.</p><p><b>RESULTS</b>Microarray results showed that levels of 152 Mycobacterium tuberculosis (Mtb)-antigen- specific IgG were significantly higher in active TB patients than in LTBI patients (P < 0.05), and these differentially expressed antigens showed stronger associations with each other and were involved in various biological processes. Eleven candidate antigens were further validated using ELISA and showed consistent results in microarray analysis. ROC analysis showed that antigens Rv2031c, Rv1408, and Rv2421c had higher areas under the curve (AUCs) of 0.8520, 0.8152, and 0.7970, respectively. In addition, both antigen combination and logistic regression analysis improved the diagnostic ability.</p><p><b>CONCLUSION</b>Several antigens have the potential to serve as serum biomarkers for discrimination between LTBI and active TB.</p>

Interleukin 8 Gene Polymorphisms Are Not Associated with Tuberculosis Susceptibility in the Chinese Population.

Interleukin 8 (IL8) is an important chemokine that elicits host immune response against tuberculosis (TB). However, whether there is an association between IL8 gene polymorphism and TB susceptibility in the Chinese population is unknown. IL8 gene was amplified and sequenced to search for nucleotide polymorphisms among the Chinese population. Four single nucleotide polymorphisms (SNPs) were identified, selected, and analyzed in a cohort of 438 patients with TB and 536 healthy controls. Allelic, genotypic, and haplotypic analysis demonstrated that the distribution of the four IL8 SNPs between patients with TB and healthy controls was not significantly different (P>0.05). The four IL8 SNPs detected in this study were not associated with TB susceptibility in the Chinese population. Secretion of IL8 by peripheral blood cells was greatly stimulated upon exposure to Mycobacterium tuberculosis whole cell extract, but such enhanced secretion was not associated with the IL8 rs4073 alleles.

Interleukin 8 Gene Polymorphisms Are Not Associated with Tuberculosis Susceptibility in the Chinese Population / 生物医学与环境科学（英文）

Interleukin 8 (IL8) is an important chemokine that elicits host immune response against tuberculosis (TB). However, whether there is an association between IL8 gene polymorphism and TB susceptibility in the Chinese population is unknown. IL8 gene was amplified and sequenced to search for nucleotide polymorphisms among the Chinese population. Four single nucleotide polymorphisms (SNPs) were identified, selected, and analyzed in a cohort of 438 patients with TB and 536 healthy controls. Allelic, genotypic, and haplotypic analysis demonstrated that the distribution of the four IL8 SNPs between patients with TB and healthy controls was not significantly different (P>0.05). The four IL8 SNPs detected in this study were not associated with TB susceptibility in the Chinese population. Secretion of IL8 by peripheral blood cells was greatly stimulated upon exposure to Mycobacterium tuberculosis whole cell extract, but such enhanced secretion was not associated with the IL8 rs4073 alleles.

L-Cysteine inhibits root elongation through auxin/PLETHORA and SCR/SHR pathway in Arabidopsis thaliana.

L-Cysteine plays a prominent role in sulfur metabolism of plants. However, its role in root development is largely unknown. Here, we report that L-cysteine reduces primary root growth in a dosage-dependent manner. Elevating cellular L-cysteine level by exposing Arabidopsis thaliana seedlings to high L-cysteine, buthionine sulphoximine, or O-acetylserine leads to altered auxin maximum in root tips, the expression of quiescent center cell marker as well as the decrease of the auxin carriers PIN1, PIN2, PIN3, and PIN7 of primary roots. We also show that high L-cysteine significantly reduces the protein level of two sets of stem cell specific transcription factors PLETHORA1/2 and SCR/SHR. However, L-cysteine does not downregulate the transcript level of PINs, PLTs, or SCR/SHR, suggesting that an uncharacterized post-transcriptional mechanism may regulate the accumulation of PIN, PLT, and SCR/SHR proteins and auxin transport in the root tips. These results suggest that endogenous L-cysteine level acts to maintain root stem cell niche by regulating basal- and auxin-induced expression of PLT1/2 and SCR/SHR. L-Cysteine may serve as a link between sulfate assimilation and auxin in regulating root growth.

microRNA response element­regulated TIKI2 expression suppresses the tumorigencity of malignant gliomas.

Glioma is the most common brain malignancy and has a very poor prognosis. The current treatment options have a minimal benefit on prolonging patient survival time. Accumulating data have shown that the WNT signaling pathway has a critical function in the progression and invasion of glioma. Thus, targeting WNT signaling appears to be an effective anti­glioma strategy. TIKI2 was recently found to suppress the activation of the WNT signaling pathway by post­translationally modifying secreted WNT proteins. The implication of TIKI2 aberrance in cancers and its potential therapeutic effect, however, has not been studied. In the present study, a glioma­specific adenoviral vector was constructed, which was regulated by response elements of miR­124, to express TIKI2 in glioma cells (Ad­TIKI2­124). Ad­TIKI2­124 was found to potently suppress the activation of WNT signaling in glioma cells. This inhibitory effect on the WNT signaling pathway lead to the reduction in proliferation, colony formation ability and invasion of glioma cell lines. In addition, animal experiments confirmed that the expression of the Ad­TIKI2­124 construct could compromise the tumorigenicity of glioma cells in vivo. Furthermore, this glioma­selective TIKI2 expression protected normal cells from toxicity. In conclusion, the present study demonstrated that adenovirus­mediated TIKI2 therapy may be used for glioma treatment and therefore warrants further clinical studies.

Sulfur nutrient availability regulates root elongation by affecting root indole-3-acetic acid levels and the stem cell niche.

Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report the response of Arabidopsis thaliana L. root development and growth to different levels of sulfate, demonstrating that low sulfate levels promote the primary root elongation. By using various reporter lines, we examined in vivo IAA level and distribution, cell division, and root meristem in response to different sulfate levels. Meanwhile the dynamic changes of in vivo cysteine, glutathione, and IAA levels were measured. Root cysteine, glutathione, and IAA levels are positively correlated with external sulfate levels in the physiological range, which eventually affect root system architecture. Low sulfate levels also downregulate the genes involved in auxin biosynthesis and transport, and elevate the accumulation of PLT1 and PLT2. This study suggests that sulfate level affects the primary root elongation by regulating the endogenous auxin level and root stem cell niche maintenance.

LSCHL4 from Japonica Cultivar, which is allelic to NAL1, increases yield of indica super rice 93-11.

The basic premise of high yield in rice is to improve leaf photosynthetic efficiency and coordinate the source-sink relationship in rice plants. Quantitative trait loci (QTLs) related to morphological traits and chlorophyll content of rice leaves were detected at the stages of heading to maturity, and a major QTL (qLSCHL4) related to flag leaf shape and chlorophyll content was detected at both stages in recombinant inbred lines constructed using the indica rice cultivar 93-11 and the japonica rice cultivar Nipponbare. Map-based cloning and expression analysis showed that LSCHL4 is allelic to NAL1, a gene previously reported in narrow leaf mutant of rice. Overexpression lines transformed with vector carrying LSCHL4 from Nipponbare and a near-isogenic line of 93-11 (NIL-9311) had significantly increased leaf chlorophyll content, enlarged flag leaf size, and improved panicle type. The average yield of NIL-9311 was 18.70% higher than that of 93-11. These results indicate that LSCHL4 had a pleiotropic function. Exploring and pyramiding more high-yield alleles resembling LSCHL4 for super rice breeding provides an effective way to achieve new breakthroughs in raising rice yield and generate new ideas for solving the problem of global food safety.

Differences in the population of genetics of Mycobacterium tuberculosis between urban migrants and local residents in Beijing, China.

BACKGROUND: Currently, migration has become one of the risk factors of high burden of tuberculosis in China. This study was to explore the influence of mass migration on the dynamics of Mycobacterium (M.) tuberculosis in Beijing, the capital and an urban area of China. METHODS: Three hundred and thirty-six M. tuberculosis strains from the Changping district, where the problem of urban migrants was more pronounced than in other Beijing regions, were genotyped by Spoligotyping, large sequence polymorphisms (LSPs 105 and 181), and variable number tandem repeat (VNTR) typing. Based on the genotype data, the phylogeny of the isolates was studied. RESULTS: In Changping district, the proportion of Beijing lineage M. tuberculosis isolates amounted to 89.0% (299/336), among which 86.6 % (252) belonged to the modern lineage. The frequency of modern Beijing lineage strains is so high (around 75% (252/336)) that associated risk factors affecting the tuberculosis epidemic cannot be determined. The time to the most recent common ancestor (TMRCA) of the Beijing lineage strains was estimated to be 5073 (95% CI: 4000-6200) years. There was no significant difference in the genetic variation of Beijing isolates from urban migrants and local residents. CONCLUSIONS: The clone of modern Beijing lineage M. tuberculosis, which is dominant in the Beijing area, most likely started to expand with the five thousand-year-old Chinese civilization. In the future, with the urbanization in the whole of China, modern Beijing lineage M. tuberculosis may gain the larger geographical spread.