Association between co-infection with Chlamydia trachomatis or Mycoplasma genitalium and cervical lesions in HPV-positive population in Hunan, China: a cross-sectional study.

OBJECTIVES: The aim of this study was to determine the prevalence of Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) among HPV-positive women undergoing colposcopy at the Second Xiangya Hospital of Central South University, Hunan, China. Additionally, we aimed to assess the impact of C. trachomatis or M. genitalium co-infection with HPV on the severity of cervical lesions. METHODS: We collected HPV data, cervical cytology results, and demographic information from 439 women attending colposcopy. Cervical swabs were obtained for simultaneous amplification testing (SAT) of C. trachomatis and M. genitalium. Multivariate logistic regression analyses were performed to examine the association between sexually transmitted pathogens and cervical lesions. RESULTS: Among the participants, C. trachomatis was detected in 17 (3.87%) individuals, and M. genitalium in 16 (3.64%) individuals. There was no co-infection of C. trachomatis and M. genitalium. The highest prevalence of M. genitalium was observed in women aged 19-30 years (10.20%; 95% CI, 1.41-18.99%), with a subsequent decline in prevalence with increasing age (Ptrend = 0.014). The most common HPV subtype in our study was HPV52 (30.79%), followed by HPV16 (18.62%), HPV58 (16.95%), and HPV53 (10.02%). Infection with HPV16 (OR = 3.43, 95% CI, 2.13-5.53), HPV31 (OR = 3.70, 95% CI, 1.44-9.50), and HPV33 (OR = 3.71, 95% CI, 1.43-9.67) was associated with an increased severity of cervical lesions, while HPV53 infection was not likely to lead to advanced cervical lesions (OR = 0.45, 95% CI, 0.23-0.89). The leukocyte level in vaginal secretions (P = 0.042) and cervical cytology results (P < 0.001) showed associations with the degree of cervical lesions. However, there was no significant association between C. trachomatis or M. genitalium infection and the severity of cervical lesions, nor with their co-infection with HPV16. CONCLUSIONS: There was no correlation between co-infection of Chlamydia trachomatis or Mycoplasma genitalium and the degree of cervical lesions in HPV-positive population in Hunan, China. Our findings emphasized the need to pay more attention to M. genitalium infection among young women. Increased levels of leukocytes in vaginal secretions may be linked to cervical lesions. HPV16, HPV31, and HPV33 in Hunan province, China, may exhibit higher cervical pathogenicity.

GSDMD-mediated pyroptosis restrains intracellular Chlamydia trachomatis growth in macrophages.

Pyroptosis, a type of programmed necrosis associated with inflammatory, is a host defense mechanism against microbial infections. Although Chlamydia has been shown to induce pyroptosis, whether pyroptosis directly impacts the growth of Chlamydia has not been demonstrated. In this study, we found that C. trachomatis L2 infection of the mouse macrophage RAW 264.7 cells induced pyroptosis by monitoring the ultrastructural changes under transmission electron microscopy and the release of LDH and IL-1ß. More importantly, this C. trachomatis-triggered pyroptosis with activation of caspase-1 and caspase-11 was also accompanied by gasdermin D (GSDMD) activation. Suppression of these two inflammatory caspases inhibited GSDMD activation. Interestingly, the C. trachomatis-triggered pyroptosis significantly inhibited the intracellular growth of C. trachomatis since inactivation of either GSDMD or caspase-1/11 significantly rescued infectious C. trachomatis yields, which suggests pyroptosis response can be utilized as an intrinsic mechanism to restrict C. trachomatis intracellular infection in addition to the well- documented extrinsic mechanisms by recruiting and enhancing inflammatory responses. This study may reveal novel targets for attenuating C. trachomatis infectivity and/or pathogenicity.

Targeting CXCR4 to suppress glioma-initiating cells and chemoresistance in glioma.

Glioma initiating cells (GICs), also known as glioma stem cells, display the capacity to recapitulate the functional diversity within the tumor. Despite the great progress achieved over the last decades, defining the key molecular regulators of GICs has represented a major obstacle in this field. In our study, data from The Cancer Genome Atlas database illustrated a relationship between C-X-C motif chemokine receptor 4 (CXCR4) expression and the survival of glioma patients. Mechanistically, we further indicated that CXCR4 mediated the upregulation of Kruppel like factor 5 (KLF5), a zinc-finger-containing transcription factor, to facilitate the proliferation of GICs. What's more, CXCR4 also enhanced the chemoresistance through KLF5/Bcl2-like 12 (BCl2L12) in glioma. The elevated expression of KLF5 and BCL2L12 induced by CXCR4 was dependent on phosphoinositide 3-kinases (PI3K)/serine/threonine kinase (AKT) signaling. Importantly, combined application of temozolomide and a CXCR4 inhibitor efficiently reversed CXCR4 mediated drugs resistance and improved anticancer effects in vivo. Collectively, our findings confirmed that CXCR4 promoted GICs proliferation via the KLF5/BCL2L12 dependent pathway, which may enrich the understanding of GICs and help drive the design of efficacious therapeutic strategies.

Dynamic evolution of small signalling peptide compensation in plant stem cell control.

Gene duplications are a hallmark of plant genome evolution and a foundation for genetic interactions that shape phenotypic diversity1-5. Compensation is a major form of paralogue interaction6-8 but how compensation relationships change as allelic variation accumulates is unknown. Here we leveraged genomics and genome editing across the Solanaceae family to capture the evolution of compensating paralogues. Mutations in the stem cell regulator CLV3 cause floral organs to overproliferate in many plants9-11. In tomato, this phenotype is partially suppressed by transcriptional upregulation of a closely related paralogue12. Tobacco lost this paralogue, resulting in no compensation and extreme clv3 phenotypes. Strikingly, the paralogues of petunia and groundcherry nearly completely suppress clv3, indicating a potent ancestral state of compensation. Cross-species transgenic complementation analyses show that this potent compensation partially degenerated in tomato due to a single amino acid change in the paralogue and cis-regulatory variation that limits its transcriptional upregulation. Our findings show how genetic interactions are remodelled following duplications and suggest that dynamic paralogue evolution is widespread over short time scales and impacts phenotypic variation from natural and engineered mutations.

UiO-66 Selective Enrichment Integrated with Thermal Desorption GC-MS for Detection of Benzene Homologues in Ambient Air.

In this study, UiO-66 was selected as sorbent media packed in the tube to selectively enrich trace levels of benzene homologues such as benzene, toluene, and xylene (BTX) in ambient air prior to thermal desorption (TD)-GC-MS determination. A series of experiments were conducted to obtain the optimal TD conditions. The results indicated that the optimal TD parameters were as follows: desorption temperature of 180°C, desorption flow rate of 50 mL min-1, and desorption time of 30 min. Furthermore, the method based on UiO-66 enrichment integrated with TD-GC-MS for trace levels of BTX was successfully developed. It exhibited a good linearity (R 2 > 0.99) in the range of 50-1000 ng, except for p, m-xylene in the range of 100-2000 ng, and achieved the recovery of 69.4-101.3%, and the relative standard deviation of 3.8-6.4%. The detection limits of BTX were 1.6-4.0 ng; according to 10 L of sampling volume, the method detection limits would be in the range of 0.16-0.40 µg m-3. Additionally, the method was successfully applied to determine BTX in indoor air and showed good selectivity and sensitivity. In summary, the findings in this work revealed that UiO-66 was an attractive adsorbent for selective enrichment trace levels of BTX compounds in ambient air, which was favorable for the subsequent detection by TD-GC-MS.

ROS regulated reversible protein phase separation synchronizes plant flowering.

How aerobic organisms exploit inevitably generated but potentially dangerous reactive oxygen species (ROS) to benefit normal life is a fundamental biological question. Locally accumulated ROS have been reported to prime stem cell differentiation. However, the underlying molecular mechanism is unclear. Here, we reveal that developmentally produced H2O2 in plant shoot apical meristem (SAM) triggers reversible protein phase separation of TERMINATING FLOWER (TMF), a transcription factor that times flowering transition in the tomato by repressing pre-maturation of SAM. Cysteine residues within TMF sense cellular redox to form disulfide bonds that concatenate multiple TMF molecules and elevate the amount of intrinsically disordered regions to drive phase separation. Oxidation triggered phase separation enables TMF to bind and sequester the promoter of a floral identity gene ANANTHA to repress its expression. The reversible transcriptional condensation via redox-regulated phase separation endows aerobic organisms with the flexibility of gene control in dealing with developmental cues.

Bioinformatics analysis of epitope-based vaccine design against the novel SARS-CoV-2.

BACKGROUND: An outbreak of infection caused by SARS-CoV-2 recently has brought a great challenge to public health. Rapid identification of immune epitopes would be an efficient way to screen the candidates for vaccine development at the time of pandemic. This study aimed to predict the protective epitopes with bioinformatics methods and resources for vaccine development. METHODS: The genome sequence and protein sequences of SARS-CoV-2 were retrieved from the National Center for Biotechnology Information (NCBI) database. ABCpred and BepiPred servers were utilized for sequential B-cell epitope analysis. Discontinuous B-cell epitopes were predicted via DiscoTope 2.0 program. IEDB server was utilized for HLA-1 and HLA-2 binding peptides computation. Surface accessibility, antigenicity, and other important features of forecasted epitopes were characterized for immunogen potential evaluation. RESULTS: A total of 63 sequential B-cell epitopes on spike protein were predicted and 4 peptides (Spike315-324, Spike333-338, Spike648-663, Spike1064-1079) exhibited high antigenicity score and good surface accessibility. Ten residues within spike protein (Gly496, Glu498, Pro499, Thr500, Leu1141, Gln1142, Pro1143, Glu1144, Leu1145, Asp1146) are forecasted as components of discontinuous B-cell epitopes. The bioinformatics analysis of HLA binding peptides within nucleocapsid protein produced 81 and 64 peptides being able to bind MHC class I and MHC class II molecules respectively. The peptides (Nucleocapsid66-75, Nucleocapsid104-112) were predicted to bind a wide spectrum of both HLA-1 and HLA-2 molecules. CONCLUSIONS: B-cell epitopes on spike protein and T-cell epitopes within nucleocapsid protein were identified and recommended for developing a protective vaccine against SARS-CoV-2.

TSP1-CD47-SIRPα signaling facilitates the development of endometriosis by mediating the survival of ectopic endometrium.

PROBLEM: To explore whether the thrombospondin-1(TSP1)-CD47-signal regulatory protein alpha (SIRPα) signaling pathway has impacts on the development of endometriosis. METHOD OF STUDY: Endometrial stromal cells (ESCs) originated from ectopic and eutopic endometrial tissues with or without endometriosis. Monocytes (Macrophages) were isolated from peripheral blood and peritoneal fluids with or without endometriosis. The expression levels of molecules were investigated by flow cytometry (FCM), immunohistochemistry (IHC), and RT-qPCR. The concentration of TSP1 was assessed via ELISA. The capacities of angiogenesis and phagocytosis were measured via tube formation assay and phagocytic assay, respectively. RESULTS: We confirmed the up-regulation of critical molecules within the pathway in endometriosis patients. TSP1 can encourage normal ESCs (NESCs) growth and fibrosis. It simultaneously promotes the secretion of inflammatory factors and inhibits the phagocytic abilities of macrophages. Moreover, the proliferation of vascular endothelial cells (VECs) may be improved by TSP1. These effects may be offset by CD47 blocking antibodies. In addition, ectopic ESCs (EESCs) directly improve SIRPα expression on macrophages, which may further exhaust their phagocytic ability. Phagocytosis efficiency of macrophages on EESCs significantly improves by blocking CD47-SIRPα pathway. CONCLUSION: TSP1-CD47-SIRPα signaling pathway not only improves the viability of NESCs per se but also promotes their survival circumstances by affecting the function of macrophages and VECs, which are mutually reinforcing and jointly promote the development of endometriosis.

Changes of serum interleukin-6 in healthy pregnant women and establishment of relevant reference intervals.

OBJECTIVE: To explore the changes of serum interleukin-6 (IL-6) levels in healthy pregnant women and establish reference intervals (RIs). METHOD: According to the requirements for the RIs study model and the reference population screening criteria in C28-A3 document, Serum IL-6 levels were measured by electrochemiluminescence immunoassay in 480 healthy Chinese women, including 120 pregnant women in each of the first, second and third trimester and 120 non-pregnant women as the negative control. The establishment of RIs for IL-6 were defined using nonparametric percentile. RESULTS: The RIs for serum IL-6 levels in healthy pregnant women is <4.19 pg/ml, the RIs for serum IL-6 levels in healthy pregnant women who are in the first trimester is <3.52 pg/ml, and the RIs for serum IL-6 levels in healthy pregnant women who are in the second and third trimester is <4.40 pg/ml. CONCLUSIONS: Serum IL-6 level in healthy pregnant women is higher than the healthy non-pregnant women, and the level of IL-6 who are in the second and third trimester is higher than those in the first. This paper successfully established RIs for serum IL-6 levels in pregnant women, providing a reference for clinical medical staff and laboratory workers.

Elevated heme impairs macrophage phagocytosis in endometriosis.

Endometriosis (EMS) is a chronic inflammatory disease characterized by the presence of extrauterine endometrial tissues. It has been previously reported that the refluxed blood containing viable endometrial tissues and the defective elimination of peritoneal macrophages in the pelvic cavity may involve in EMS pathogenesis. However, the mechanism by which macrophages exhibit attenuated phagocytic capability in EMS remains undetermined. Herein, we found that heme, the byproduct of lysed erythrocytes, accumulated abnormally in the peritoneal fluid (PF) of patients with EMS (14.22 µmol/L, 95% confidence interval (CI): 12.54-16.71), compared with the EMS-free group (9.517 µmol/L, 95% CI: 8.891-10.1053). This abnormal accumulation was not associated with the color of PF, phase of the menstrual cycle or severity of the disease. The reduced phagocytic ability of peritoneal macrophages (pMφs) was observed in the EMS group. Consistently, a high-concentration (30 µmol/L) heme treatment impaired EMS-pMφs phagocytosis more than a low-concentration (10 µmol/L) heme treatment. A similar phenomenon was observed in the EMS-free control pMφs (Ctrl-pMφs) and the CD14+ peripheral monocytes (CD14+ Mos). These results indicated that a high heme concentration exhibits a negative effect on macrophage phagocytosis, which supplements the mechanism of impaired scavenger function of pMφs in EMS.

Association between CD16++ monocytes in peripheral blood and clinical features and short-term therapeutic effects of polycystic ovary syndrome.

OBJECTIVE: To evaluate the association between CD16++ monocytes in peripheral blood and the clinical features and short-term therapeutic effects of polycystic ovary syndrome (PCOS). METHODS: This prospective cross-sectional study included women diagnosed with PCOS at a University Hospital in Shanghai, China, between June 4 and November 28, 2016. Patients received Diane-35, metformin, or both combined for 3 months. We collected anthropometric measures and used flow cytometry to detect CD16++ monocytes. RESULTS: The final analysis included 70 patients: 18 in the Diane-35 group, 30 in the metformin group, and 22 in the Diane-35 plus metformin group. The control group comprised 60 women without PCOS. The proportion of CD16++ monocytes was significantly higher in patients with PCOS than in those with no PCOS (16.05% vs 10.73%; P=0.001). The proportion differed significantly between patients with and those without hyperandrogenism (13.12% vs 17.30%; P=0.002) and showed moderate accuracy in diagnosing hyperandrogenism before treatment. We noted a decrease in monocytes post-treatment in patients given metformin and Diane-35 plus metformin. CONCLUSIONS: The proportion of CD16++ monocytes was most significantly associated with hyperandrogenism before treatment. Our findings suggest that the proportion of CD16++ monocytes in peripheral blood might be related to the inflammatory condition of PCOS.

Insights of efferocytosis in normal and pathological pregnancy.

Efferocytosis, which is known as the phagocytic clearance of dying cells by professional as well as non-professional phagocytes, including a great number of intracellular/extracellular factors and signals, is interrelated with the immune system, contributing to local and systemic homeostasis, especially in tissues with high constitutive rates of apoptosis. Accumulating studies have indicated that immune dysregulation is associated with the pathogenesis of the female reproductive system, which causes preeclampsia (PE), recurrent spontaneous abortion (RSA), ruptured ectopic pregnancy, and so on. And some studies have revealed the pleiotropic and essential role of efferocytosis in these obstetrical disorders. More specifically, the occurrence and development of these diseases were in connection with some efferocytosis-related factors and signals, such as C1q, MBL, and IL-33/ST2. In this review, we systematically review the diverse impacts of efferocytosis in immune system and discuss its relevance to normal and pathological pregnancy. These findings may instruct future basic researches as well as clinical applications of efferocytosis-related factors and signals as latent predictors or therapeutic targets on the obstetrical disorders.

Chlamydial plasmid-encoded virulence factor Pgp3 interacts with human cathelicidin peptide LL-37 to modulate immune response.

We have previously reported that Chlamydia trachomatis plasmid-encoded Pgp3 is able to neutralize anti-chlamydial activity of human cathelicidin peptide LL-37 by binding to and forming stable complex with LL-37. Besides its microbicidal activity, LL-37 also modulates immune response, including inducing cytokine/chemokine production in fibroblast/epithelial cells and recruitment of inflammatory cells. We now report that LL-37 was significantly induced in the genital tracts of women diagnosed positive for C. trachomatis. Both the LL-37-stimulated IL-6/8 production in human endometrial epithelial cells and the LL-37-induced neutrophil chemotaxis were blocked by Pgp3. Interestingly, although Pgp3 itself alone could not induce cytokines in epithelial cell cells, it did so in neutrophils. Importantly, the Pgp3 proinflammatory activity in neutrophils was significantly enhanced by forming complex with LL-37 although LL-37 alone failed to induce cytokine production in neutrophils. Thus, we have demonstrated that Pgp3 can modulate the proinflammatory activities of LL-37 on epithelial cells by forming stable complex with LL-37 but the Pgp3's own proinflammatory activity on myeloid cells is enhanced by forming the same complex. We hypothesize that Chlamydia may use Pgp3 to both block detrimental inflammation for improving its own fitness in the genital tract epithelial tissue and activate myeloid cell-mediated inflammation for potentially promoting spreading between the hosts, the latter of which may inevitably contribute to the development of inflammatory sequelae such as tubal fibrosis.

IL-33/ST2 axis affects the polarization and efferocytosis of decidual macrophages in early pregnancy.

PROBLEM: To explore whether IL-33/ST2 axis modulates the polarization and efferocytosis of decidual macrophages (dMφs). METHOD OF STUDY: The phenotype characteristics of dMφs from both normal pregnant women and recurrent spontaneous abortion (RSA) patients were determined by real-time polymerase chain reaction (RT-PCR) and flow cytometry (FCM). Then, the efferocytosis and expression of IL-33 and its receptor (ST2) in dMφs were analyzed by FCM. Finally, the effects of sST2, a decoy receptor for IL-33 that inhibits the IL-33/ST2 signaling pathway, on the polarization and efferocytosis of dMφs and human macrophage cell line U937 were investigated. RESULTS: Compared with normal pregnancy, dMφs from RSA patients presented a M1 phenotype with high secretion of IL-33, whereas the expression of ST2 decreased. However, dMφs from RSA patients possessed a more powerful efferocytosis ability to clear the apoptotic decidual stromal cells (DSCs) compared with dMφs from normal pregnancy patients. Treatment with recombinant human sST2 led to the up-regulation of M1 bias and efferocytosis ability of both normal dMφs and U937. CONCLUSION: This study indicates that IL-33 secreted by dMφs promotes M2 bias at the feto-maternal interface, and as a result, RSA might attribute to the disturbance of IL-33/ST2 axis and the enhancement of efferocytosis of dMφs subsequently.

1-Methyl-tryptophan attenuates regulatory T cells differentiation due to the inhibition of estrogen-IDO1-MRC2 axis in endometriosis.

Foxp3+ regulatory T (Treg) cells contribute to the local dysfunctional immune environment in endometriosis, an estrogen-dependent gynecological disease, which affects the function of ectopic endometrial tissue clearance by the immune system. The reason for the high percentage of peritoneal Treg in endometriosis patients is unknown. Here, we show that the proportion of peritoneal Treg cells increases as endometriosis progresses. To determine the probable mechanism, we established a naive T cell-macrophage-endometrial stromal cell (ESC) co-culture system to mimic the peritoneal cavity microenvironment. After adding 1-methyl-tryptophan (1-MT), a specific inhibitor of indoleamine 2,3-dioxygenase-1 (IDO1), to the co-culture system, we found that the differentiation of Treg cells, mainly IL-10+ Treg cells, decreased. Therefore, 1-MT-pretreated ESCs-educated Treg cells performed impaired suppressive function. Moreover, estrogen promoted the differentiation of Treg cells by elevating IDO1 expression in the ectopic lesion. Subsequently, we examined mannose receptor C, type 2 (MRC2), which is an up-stream molecule of IL-10, by bioinformatics analysis and real-time PCR validation. MRC2 expression in ectopic ESCs was notably lower than that in normal ESCs, which further negatively regulated the expression of IDO1 and Ki-67 in ESCs. Furthermore, MRC2 is required for Treg differentiation in the ectopic lesion, especially that for CD4high Treg. Therefore, MRC2-silenced ESCs-educated Treg manifested a stronger suppressive function in vitro. Consistently, the percentage of Treg increased when MRC2-shRNA was administered in the peritoneal cavity of endometriosis-disease mice model. Besides, 1-MT improved the condition of endometriosis, in terms of reducing the number and weight of total ectopic lesions in vivo. These results indicate that the estrogen-IDO1-MRC2 axis participates in the differentiation and function of Treg and is involved in the development of endometriosis. Thus, blockage of IDO1 in the ectopic lesion, which does not influence physiological functions of estrogen, may be considered a potential therapy for endometriosis.

The Chlamydia-Secreted Protease CPAF Promotes Chlamydial Survival in the Mouse Lower Genital Tract.

Despite the extensive in vitro characterization of CPAF (chlamydial protease/proteasome-like activity factor), its role in chlamydial infection and pathogenesis remains unclear. We now report that a Chlamydia trachomatis strain deficient in expression of CPAF (L2-17) is no longer able to establish a successful infection in the mouse lower genital tract following an intravaginal inoculation. The L2-17 organisms were cleared from the mouse lower genital tract within a few days, while a CPAF-sufficient C. trachomatis strain (L2-5) survived in the lower genital tract for more than 3 weeks. However, both the L2-17 and L2-5 organisms maintained robust infection courses that lasted up to 4 weeks when they were directly delivered into the mouse upper genital tract. The CPAF-dependent chlamydial survival in the lower genital tract was confirmed in multiple strains of mice. Thus, we have demonstrated a critical role of CPAF in promoting C. trachomatis survival in the mouse lower genital tracts. It will be interesting to further investigate the mechanisms of the CPAF-dependent chlamydial pathogenicity.

Chlamydia muridarum induction of glandular duct dilation in mice.

Although Chlamydia-induced hydrosalpinx in women and mice has been used as a surrogate marker for tubal infertility, the medical relevance of nontubal pathologies, such as uterine horn dilation, developed in mice following chlamydial infection remains unclear. We now report that the uterine horn dilation correlates with glandular duct dilation detected microscopically following Chlamydia muridarum infection. The dilated glandular ducts pushed the uterine horn lumen to closure or dilation and even broke through the myometrium to develop extrusion outside the uterine horn. The severity scores of uterine horn dilation observed macroscopically correlated well with the number of cross sections of the dilated glandular ducts counted under microscopy. Chlamydial infection was detected in the glandular epithelial cells, potentially leading to inflammation and dilation of the glandular ducts. Direct delivery of C. muridarum into the mouse uterus increased both uterine horn/glandular duct dilation and hydrosalpinx. However, the chlamydial plasmid, which is essential for the induction of hydrosalpinx, was not required for the induction of uterine horn/glandular duct dilation. Screening 12 strains of mice for uterine horn dilation following C. muridarum infection revealed that B10.D2, C57BL/10J, and C57BL/6J mice were most susceptible, followed by BALB/cJ and A/J mice. Deficiency in host genes involved in immune responses failed to significantly alter the C. muridarum induction of uterine horn dilation. Nevertheless, the chlamydial induction of uterine horn/glandular duct dilation may be used to evaluate plasmid-independent pathogenicity of Chlamydia in susceptible mice.

Chlamydia-secreted protease CPAF degrades host antimicrobial peptides.

Chlamydia trachomatis infection in the lower genital tract, if untreated, can ascend to the upper genital tract, potentially leading to complications such as tubal factor infertility. The ascension involves cell-to-cell spreading, which may require C. trachomatis organisms to overcome mucosal extracellular effectors such as antimicrobial peptides. We found that among the 8 antimicrobial peptides tested, the cathelicidin LL-37 that is produced by both urogenital epithelial cells and the recruited neutrophils possessed a most potent antichlamydial activity. Interestingly, this antichlamydial activity was completely inhibited by CPAF, a C. trachomatis-secreted serine protease. The inhibition was dependent on CPAF's proteolytic activity. CPAF selectively degraded LL-37 and other antimicrobial peptides with an antichlamydial activity. CPAF is known to secrete into and accumulate in the infected host cell cytoplasm at the late stage of chlamydial intracellular growth and may be released to confront the extracellular antimicrobial peptides before the intra-inclusion organisms are exposed to extracellular environments during host cell lysis and chlamydial spreading. Thus, the finding that CPAF selectively targets host antimicrobial peptides that possess antichlamydial activities for proteolysis suggests that CPAF may contribute to C. trachomatis pathogenicity by aiding in ascending infection.

[A Method to Reconstruct Surface Reflectance Spectrum from Multispectral Image Based on Canopy Radiation Transfer Model].

Due to the lack of enough spectral bands for multi-spectral sensor, it is difficult to reconstruct surface retlectance spectrum from finite spectral information acquired by multi-spectral instrument. Here, taking into full account of the heterogeneity of pixel from remote sensing image, a method is proposed to simulate hyperspectral data from multispectral data based on canopy radiation transfer model. This method first assumes the mixed pixels contain two types of land cover, i.e., vegetation and soil. The sensitive parameters of Soil-Leaf-Canopy (SLC) model and a soil ratio factor were retrieved from multi-spectral data based on Look-Up Table (LUT) technology. Then, by combined with a soil ratio factor, all the parameters were input into the SLC model to simulate the surface reflectance spectrum from 400 to 2 400 nm. Taking Landsat Enhanced Thematic Mapper Plus (ETM+) image as reference image, the surface reflectance spectrum was simulated. The simulated reflectance spectrum revealed different feature information of different surface types. To test the performance of this method, the simulated reflectance spectrum was convolved with the Landsat ETM + spectral response curves and Moderate Resolution Imaging Spectrometer (MODIS) spectral response curves to obtain the simulated Landsat ETM+ and MODIS image. Finally, the simulated Landsat ETM+ and MODIS images were compared with the observed Landsat ETM+ and MODIS images. The results generally showed high correction coefficients (Landsat: 0.90-0.99, MODIS: 0.74-0.85) between most simulated bands and observed bands and indicated that the simulated reflectance spectrum was well simulated and reliable.