CgNis1's Impact on Virulence and Stress Response in Colletotrichum gloeosporioides.

Pepper anthracnose caused by Colletotrichum gloeosporioides infection is an important fungal disease and represents a serious threat to pepper yield and quality. At present, the pathogenic molecular mechanism of C. gloeosporioides is not very clear. In our study, we characterized the function of C. gloeosporioides CgNis1, a homolog of Magnaporthe oryzae MoNis1. We found that the ∆Cgnis1 mutant reduced the growth rate and was defective in conidiation. Although the rate of appressorium formation was unaffected, the germ tube was found to be abnormal. CgNis1 was shown to be involved in the H2O2 stress response and maintaining cell membrane permeability. The pathogenicity assays performed in this study indicated that the deletion of CgNIS1 is associated with virulence. Our results indicate that CgNis1 is necessary for the growth, development, and pathogenicity of the fungus. This work provides an in-depth analysis of the Nis1 protein, helps to enhance studies on pathogen-related molecular mechanisms, and provides a theoretical basis for the prevention and control of C. gloeosporioides in peppers.

A method for high-precision measuring differential transformer asymmetry.

The differential transformer is an important component in the front-end electronics of high-precision capacitive position sensing circuits, which are widely employed in space inertial sensors and electrostatic accelerometers. The position sensing offset, one of the space inertial sensors' most critical error sources in the performance range, is dominated by the differential transformer asymmetry and requires a high-precision evaluation. This paper proposes a method to assess differential transformers' asymmetry and realize a prototype circuit to test a transformer sample. The results show that the asymmetry measurement precision can achieve 0.6 ppm for the transformer with an asymmetry level of about -278.2 ppm.

Analysis of serum exosome microRNAs in the rat model of chronic obstructive pulmonary disease.

BACKGROUND: MicroRNAs (miRNAs) play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms underlying the function of miRNAs remain to be fully understood. This study aimed to explore the profile of serum exosome-derived miRNAs in the rat model of COPD. METHODS: We established the COPD rat model by cigarette smoke exposure (CSE). The pulmonary function and morphological changes were analyzed. Serum exosomes were examined by transmission electron microscopy (TEM) and western blotting. The differentially expressed miRNAs between COPD and healthy rats were screened from exosome-derived small RNA library using bioinformatics analysis and experimentally verified in rat lung tissues by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: The pulmonary function indexes in COPD rats were significantly decreased compared to control rats. The typical pathological manifestations of emphysema were observed in COPD rats. Marker proteins (CD9, CD63, and TSG101) and characteristic morphology features were detected in serum exosomes. Fifteen differentially expressed miRNAs were identified in the small RNA library. In addition, we confirmed that the expression of miR-185-5p and miR-182-5p was significantly down-regulated in the lung tissues of COPD rats compared to control rats. CONCLUSION: The expression of miR-185-5p and miR-182-5p was down-regulated in serum-derived exosomes and lung tissues of COPD rats, indicating that these two miRNAs might be involved in the development of COPD and might serve as potential biomarkers for the diagnosis of COPD.

Metagenomic next-generation sequencing indicates more precise pathogens in patients with pulmonary infection: A retrospective study.

Background: Timely identification of causative pathogens is important for the diagnosis and treatment of pulmonary infections. Metagenomic next-generation sequencing (mNGS), a novel approach to pathogen detection, can directly sequence nucleic acids of specimens, providing a wide range of microbial profile. The purpose of this study was to evaluate the diagnostic performance of mNGS in the bronchoalveolar lavage fluid (BALF) of patients with suspected pulmonary infection. Methods: From April 2019 to September 2021, 502 patients with suspected pneumonia, who underwent both mNGS of BALF and conventional microbiological tests (CMTs), were classified into different groups based on comorbidities. The diagnostic performances of mNGS and CMTs were compared. Comprehensive clinical analysis was used as the reference standard. Results: The diagnostic accuracy and sensitivity of mNGS were 74.9% (95% confidence interval [CI], 71.7-78.7%) and 72.5% (95% CI, 68.2-76.8%) respectively, outperformed those of CMTs (36.9% diagnostic accuracy, 25.4% sensitivity). For most pathogens, the detection rate of mNGS was higher than that of CMTs. Polymicrobial infections most often occurred in immunocompromised patients (22.1%). Only 2.3% patients without underlying diseases developed polymicrobial infections. Additionally, the spectrums of pathogens also varied among the different groups. We found the positive predictive values (PPV) to be dependent upon both the pathogen of interest as well as the immunologic status of the patient (e.g., the PPV of Mycobacterium tuberculosis was 94.9% while the PPV of Pneumocystis jirovecii in immunocompetent individuals was 12.8%). This information can help physicians interpret mNGS results. Conclusion: mNGS of BALF can greatly enhance the accuracy and detection rate of pathogens in patients with pulmonary infections. Moreover, the comorbidities and types of pathogens should be taken consideration when interpreting the results of mNGS.

Obstructive sleep apnea is associated with cognitive impairment in minor ischemic stroke.

OBJECTIVES: Obstructive sleep apnea (OSA) is commonly seen in stroke patients, and its relationship with cognitive impairment remains poorly understood. This study aimed to explore the roles of OSA in cognition impairment in patients with minor ischemic stroke. METHODS: Patients with minor ischemic stroke were consecutively enrolled from January 2020 to May 2021. Every patient underwent polysomnography (PSG) to assess for OSA. Based on the apnea hypopnea index (AHI), patients were grouped into the no OSA (AHI < 5), mild OSA (5 ≤ AHI < 15), and moderate-to-severe OSA (MS OSA, AHI ≥ 15) groups. Neuropsychological assessments were performed to evaluate cognitive function, and the correlations between cognitive function and OSA were investigated. RESULTS: Of 94 patients, 35 had no OSA, 32 had mild OSA, and 27 had moderate-to-severe OSA. Compared to the no or mild OSA groups, the moderate-to-severe OSA group performed worse on the Chinese version of the Auditory Verbal Learning Test (CAVLT)-Recognition (p < 0.001), Digital Span Test (DST)-Backward (p < 0.001), Montreal Cognitive Assessment (MoCA) (p < 0.001), and Stroop Color and Word Test (SCWT)-Interference (p < 0.001). The severity of cognitive impairment was assessed using the MoCA, which was negatively related to the AHI (p = 0.041) and lowest SpO2 (p = 0.048). CONCLUSIONS: The findings suggest that OSA has significant effects on cognition impairment in patients with minor ischemic stroke and that hypoxemia may be a potential pathophysiological mechanism of OSA-induced cognitive impairment.

The Naturally Evolved EPSPS From Goosegrass Confers High Glyphosate Resistance to Rice.

Glyphosate-resistant crops developed by the CP4-EPSPS gene from Agrobacterium have been planted on a massive scale globally, which benefits from the high efficiency and broad spectrum of glyphosate in weed control. Some glyphosate-resistant (GR) genes from microbes have been reported, which might raise biosafety concerns. Most of them were obtained through a hygromycin-HPT transformation system. Here we reported the plant source with 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene from goosegrass endowed rice with high resistance to glyphosate. The integrations and inheritability of the transgenes in the rice genome were investigated within two generations. The EiEPSPS transgenic plants displayed similar growth and development to wild type under no glyphosate selection pressure but better reproductive performance under lower glyphosate selection pressure. Furthermore, we reconstructed a binary vector pCEiEPSPS and established the whole stage glyphosate selection using the vector. The Glyphosate-pCEiEPSPS selection system showed a significantly higher transformation efficiency compared with the hygromycin-HPT transformation system. Our results provided a promising alternative gene resource to the development of GR plants and also extended the plant transformation toolbox.

Key Common Genes in Obstructive Sleep Apnea and Lung Cancer are Associated with Prognosis of Lung Cancer Patients.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with an increased risk of lung cancer. This study aimed to identify key common genes in OSA and lung cancer and explore their prognostic value in lung cancer. MATERIALS AND METHODS: Transcriptome data of OSA and lung cancer were obtained from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database, respectively. Genes associated with OSA and lung cancer were screened by weighted gene co-expression network analysis (WGCNA). Univariate and multivariate Cox regression algorithms were applied to identify key genes and construct the risk score model. Receiver operating characteristic (ROC) curves and a nomogram were performed to evaluate the prognostic value of the risk score. The screened key genes and their roles in prognosis were validated by GEO (GSE30219) analysis. RESULTS: A total of 104 common genes were screened in OSA and lung cancer by WGCNA. Modulator of apoptosis 1 (MOAP1), chromobox 7 (CBX7), platelet-derived growth factor subunit B (PDGFB), and mitogen-activated protein kinase 3 (MAP2K3) were identified as key genes by univariate and then multivariate Cox regression analyses. The risk score model was constructed on the basis of four gene signatures. ROC curves and the nomogram showed that the risk score had a high accuracy in predicting the survival of patients with lung cancer. In addition, the result of multivariate Cox regression analysis indicated that the risk score was an independent prognostic factor in lung cancer. CONCLUSION: This study constructed a unique model for predicting the prognosis of lung cancer patients on the basis of four genes common to OSA and lung cancer. These genes may also serve as candidate genes to improve our knowledge about the underlying mechanism of OSA that leads to an increased risk of lung cancer at the genetic level.

Overview of serpin B9 and its roles in cancer (Review).

Serine proteinase inhibitor B9 (serpin B9) is a member of the serine protease inhibitor superfamily, which is widely found in animals, plants and microorganisms. Serpin B9 has been reported to protect cells from the immune­killing effect of granzyme B (GrB) released by lymphocytes. In recent years, an increasing number of studies have indicated that serpin B9 is involved in tumour apoptosis, immune evasion, tumorigenesis, progression, metastasis, drug resistance and even in maintaining the stemness of cancer stem cells (CSCs). Moreover, according to clinical studies, serpin B9 has been demonstrated to be significantly associated with the development of precancerous lesions, a poor prognosis and ineffective therapies, suggesting that serpin B9 may be a potential target for cancer treatment and an indicator of cancer diagnosis; thus, it has begun to attract increased attention from scholars. The present review concisely described the structure and biological functions of the serpin superfamily and serpin B9. In addition, related research on serpins in cancer is discussed in order to provide a comprehensive understanding of the role of serpin B9 in cancer, as well as its clinical significance for cancer diagnosis and prognosis.

Role of hypoxia­inducible factor­2α in lung cancer (Review).

Hypoxia is a common phenomenon during tumorigenesis and tumour development. In recent years, studies have found that hypoxia­inducible factor (HIF)­2α, also referred to as endothelial PAS domain protein­1, plays an important role in tumours. HIF­2α is an important oncogene and a critical prognostic indicator in non­small cell lung cancer. However, no unified conclusion can be drawn concerning HIF­2α and small cell lung cancer, since few studies to date have focused on their association. An increasing number of studies have confirmed that HIF­2α is involved in tumorigenesis, cell proliferation, angiogenesis, metastasis, drug resistance and radiotherapy failure in lung cancer. Of note, HIF­2α plays a crucial role in lung cancer to maintain cancer cell stemness. Based on the importance of HIF­2α in lung cancer, HIF­2α­targeted therapy has been attracting increasing attention. Although this strategy currently appears to be promising in vitro, it has never been assessed as a therapy for lung cancer. The aim of the present review was to summarize the contribution of HIF­2α to various aspects of lung cancer, as well as its potential as targeted therapy.

Association between growth differentiation factor 5 rs143383 genetic polymorphism and the risk of knee osteoarthritis among Caucasian but not Asian: a meta-analysis.

BACKGROUND: A few months ago, the Bioscience Reports journal showed that growth differentiation factor 5 (GDF5) rs143383 genetic polymorphism increases the susceptibility of knee osteoarthritis (KOA), but previous studies' results have debates about available data. Considering the availability of more recent data, we focus on clarifying the relationship of KOA and GDF5 rs143383 genetic polymorphism by a meta-analysis of case-control trial data. METHODS: The eligible studies from the time of database established to Oct. 2019 were collected from PubMed, Springer, Cochrane library, Web of Science, China National Knowledge Infrastructure (CNKI), and Wan Fang library. Odds ratios (OR) and 95% confidence intervals (CI) were used to estimate the association between these polymorphisms and KOA risk. The meta-analysis was completed by STATA 18.0 software. RESULTS: A total of 196 studies were collected, 16 of them included in final meta-analysis (7997 cases and 12,684 controls). There was significant association between GDF5 rs143383 polymorphism and KOA in all genetic models (for Allele model (C versus T): OR = 0.84 (95% CI = 0.76-0.91); dominate model (CC+CT versus TT): OR = 0.80 (95% CI = 0.72-0.90); recessive model (CC versus CT+TT): OR = 0.79 (95% CI = 0.68-0.92); heterozygote model (CT versus CC+TT): OR = 0.89 (95% CI = 0.80-0.97); homozygous model (CC versus TT): OR = 0.71 (95% CI = 0.60-0.85)). In the subgroup analysis, we obtained the results that there is no significance among Asians. CONCLUSION: GDF5 rs143383 genetic polymorphism increases the risk of KOA among Caucasians; CC genotype and C allele are protective factors for the susceptibility of KOA among Caucasians.

Automated Landslides Detection for Mountain Cities Using Multi-Temporal Remote Sensing Imagery.

Landslides that take place in mountain cities tend to cause huge casualties and economic losses, and a precise survey of landslide areas is a critical task for disaster emergency. However, because of the complicated appearance of the nature, it is difficult to find a spatial regularity that only relates to landslides, thus landslides detection based on only spatial information or artificial features usually performs poorly. In this paper, an automated landslides detection approach that is aiming at mountain cities has been proposed based on pre- and post-event remote sensing images, it mainly utilizes the knowledge of landslide-related surface covering changes, and makes full use of the temporal and spatial information. A change detection method using Deep Convolution Neural Network (DCNN) was introduced to extract the areas where drastic alterations have taken place; then, focusing on the changed areas, the Spatial Temporal Context Learning (STCL) was conducted to identify the landslides areas; finally, we use slope degree which is derived from digital elevation model (DEM) to make the result more reliable, and the change of DEM is used for making the detected areas more complete. The approach was applied to detecting the landslides in Shenzhen, Zhouqu County and Beichuan County in China, and a quantitative accuracy assessment has been taken. The assessment indicates that this approach can guarantee less commission error of landslide areal extent which is below 17.6% and achieves a quality percentage above 61.1%, and for landslide areas, the detection percentage is also competitive, the experimental results proves the feasibility and accuracy of the proposed approach for the detection landslides in mountain cities.

Silencing of D-Lactate Dehydrogenase Impedes Glyoxalase System and Leads to Methylglyoxal Accumulation and Growth Inhibition in Rice.

D-Lactate is oxidized by two classes of D-lactate dehydrogenase (D-LDH), namely, NAD-dependent and NAD-independent D-LDHs. Little is known about the characteristics and biological functions of D-LDHs in rice. In this study, a functional NAD-independent D-LDH (LOC_Os07g06890) was identified in rice, as a result of alternative splicing events. Characterization of the expression profile, subcellular localization, and enzymatic properties of the functional OsD-LDH revealed that it is a mitochondrial cytochrome-c-dependent D-LDH with high affinity and catalytic efficiency. Functional analysis of OsD-LDH RNAi transgenic rice demonstrated that OsD-LDH participates in methylglyoxal metabolism by affecting the activity of the glyoxalase system and aldo-keto reductases. Under methylglyoxal treatment, silencing of OsD-LDH in rice resulted in the accumulation of methylglyoxal and D-lactate, the decrease of reduced glutathione in leaves, and ultimately severe growth inhibition. Moreover, the detached leaves of OsD-LDH RNAi plants were more sensitive to salt stress. However, the silencing of OsD-LDH did not affect the growth under photorespiration conditions. Our results provide new insights into the role of NAD-independent D-LDHs in rice.

[Processes of earth road regolith erosion in loess area].

Based on field investigation, the processes of earth road regolith erosion were studied under indoor simulated rainfall. Results showed that the runoff initiation time for both regolith and earth road surface erosion decreased with the increasing rainfall intensity and slope steepness. With the increase in regolith thickness, the initiation time for earth road surface erosion lagged for 2-5 min. When the regolith thickness was ≤ 0.5 cm, the runoff rate turned to be stable at 2 min after runoff generation, and the average runoff rate increased with the increasing rainfall intensity and decreased with the increasing slope steepness. When the regolith thickness was ≥ 1.0 cm, runoff rate turned to be stable at 3 min after runoff generation, and the average runoff rate increased linearly with the rainfall intensity but exhibited a gradually decreasing trend after the first increment with the increasing slope steepness. The critical point for regolith erosion decreased with the increasing rainfall intensity and slope steepness. With the regolith thickness of ≤ 0.5 cm, the erosion rate increased with the increasing rainfall intensity, with the erosion rate ranging from 24.5% to 434.4%, and the erosion rates for 8° and 16° slopes were 2.4 times as those for 2° and 4° slopes. With the regolith thickness of 1.0 cm, the erosion rate turned to be stable about 9 min after runoff generation and increased with the increasing rainfall intensity and slope. With the increasing slope steepness, the erosion form changed from sheet erosion to rill erosion and then to headward erosion. The average erosion amount over 10 min single rainfall for the regolith thickness of ≥ 1.0 cm was 1.3 times as that for the regolith thickness of ≤ 0.5 cm, while it was 2.7 times as that at the stage of regolith erosion alone. With the regolith thickness of ≤ 0.5 cm, the erosion amount had a significant correlation with rainfall intensity, and runoff volume with slope steepness. With the regolith thickness of ≥ 1.0 cm, both runoff and sediment yields in 10 min single rainfall had a significant correlation with rainfall intensity. The proportion of regolith erosion to the combined erosion increased with the increasing regolith thickness, while the road erosion was the main form at small regolith thickness.

The nonstructural protein 11 of porcine reproductive and respiratory syndrome virus inhibits NF-κB signaling by means of its deubiquitinating activity.

Since its emergence in the late 1980s, porcine reproductive and respiratory syndrome (PRRS) has been devastating the swine industry worldwide. The causative agent is an Arterivirus, referred to as PRRS virus (PRRSV). The pathogenic mechanisms of PRRS are poorly understood, but are believed to correlate with the ability of PRRSV to inhibit immune responses of the host. However, precisely how the virus is capable of doing so remains obscure. In this study, we showed that PRRSV infection led to reduced ubiquitination of cellular proteins. Screening all of the 12 nonstructural proteins (Nsps) encoded by PRRSV revealed that, apart from the Nsp2 which contains the deubiqintinating (DUB) ovarian tumor (OTU) domain, Nsp11, which encodes a unique and conserved endoribonuclease (NendoU) throughout the Nidovirus order, also possesses DUB activity. In vivo assay demonstrated that Nsp11 specifically removed lysine 48 (K48)-linked polyubiquitin chains and the conserved sites C112, H144, D173, K180, and Y219 were critical for its DUB activity. Remarkably, DUB activity was responsible for the capacity of Nsp11 to inhibit nuclear factor κB (NF-κB) activation. Mutations abrogating the DUB activity of Nsp11 toward K48-linked polyubiquitin chains of IκBα nullified the suppressive effect on NF-κB. Our data add Nsp11 to the list of DUBs encoded by PRRSV and uncover a novel mechanism by which PRRSV cripples host innate immune responses.

Mycobacterium tuberculosis Rv2185c contributes to nuclear factor-κB activation.

Tuberculosis caused by Mycobacterium tuberculosis has a detrimental impact on public health worldwide, especially in developing countries. The nuclear factor-κB (NF-κB) signaling pathway is reportedly involved in the innate immune response against M. tuberculosis infections. We screened the secreted proteins, membrane proteins, and lipoproteins of the M. tuberculosis H37Rv strain using luciferase activity assays. The Rv2185c protein exhibited the potential to activate NF-κB in HeLa and A549 cells. Overexpression of Rv2185c-induced IκBα degradation and nuclear translocation of NF-κB; it also induced NF-κB-dependent inflammatory factors, including interleukin (IL)-6, IL-8, IL-1ß and tumor necrosis factor (TNF)-α. The intact binding site for the NF-κB element is required for the activation of Rv2185c-induced IL-6 and IL-8 gene expression. NF-κB activation and NF-κB-regulated genes encoding TNF-α and TNF-related apoptosis-inducing ligand have also been shown to be involved in Rv2185c-induced apoptosis.

Ubiquitin-specific proteases 25 negatively regulates virus-induced type I interferon signaling.

Ubiquitination and deubiquitination have emerged as critical regulatory processes in the virus-triggered type I interferon (IFN) induction pathway. In this study, we carried out a targeted siRNA screen of 54 ubiquitin-specific proteases (USPs) and identified USP25 as a negative regulator of the virus-triggered type I IFN signaling pathway. Overexpression of USP25 inhibited virus-induced activation of IFN-ß, interferon regulation factor 3 (IRF3) and nuclear factor-kappa B (NF-κB), as well as the phosphorylation of IRF3 and NF-κB subunit p65. Furthermore, Knockdown of USP25 potentiated virus-induced induction of the IFN-ß. In addition, detailed analysis demonstrated that USP25 cleaved lysine 48- and lysine 63-linked polyubiquitin chains in vitro and in vivo, and its deubiquitinating enzyme (DUB) activity, were dependent on a cysteine residue (Cys178) and a histidine residue (His607). USP25 mutants lacking DUB activity lost the ability to block virus-induced type I IFN to some degree. Mechanistically, USP25 deubiquitinated retinoic acid-inducible gene I (RIG-I), tumornecrosis factor (TNF) receptor-associated factor 2 (TRAF2), and TRAF6 to inhibit RIG-I-like receptor-mediated IFN signaling. Our findings suggest that USP25 is a novel DUB negatively regulating virus-induced type I IFN production.

Foot-and-mouth disease virus 3C protease cleaves NEMO to impair innate immune signaling.

Foot-and-mouth disease is a highly contagious viral illness of wild and domestic cloven-hoofed animals. The causative agent, foot-and-mouth disease virus (FMDV), replicates rapidly, efficiently disseminating within the infected host and being passed on to susceptible animals via direct contact or the aerosol route. To survive in the host, FMDV has evolved to block the host interferon (IFN) response. Previously, we and others demonstrated that the leader proteinase (L(pro)) of FMDV is an IFN antagonist. Here, we report that another FMDV-encoded proteinase, 3C(pro), also inhibits IFN-α/ß response and the expression of IFN-stimulated genes. Acting in a proteasome- and caspase-independent manner, the 3C(pro) of FMDV proteolytically cleaved nuclear transcription factor kappa B (NF-κB) essential modulator (NEMO), a bridging adaptor protein essential for activating both NF-κB and interferon-regulatory factor signaling pathways. 3C(pro) specifically targeted NEMO at the Gln 383 residue, cleaving off the C-terminal zinc finger domain from the protein. This cleavage impaired the ability of NEMO to activate downstream IFN production and to act as a signaling adaptor of the RIG-I/MDA5 pathway. Mutations specifically disrupting the cysteine protease activity of 3C(pro) abrogated NEMO cleavage and the inhibition of IFN induction. Collectively, our data identify NEMO as a substrate for FMDV 3C(pro) and reveal a novel mechanism evolved by a picornavirus to counteract innate immune signaling.

Cloning and characterization of a cDNA encoding type 1 diacylglycerol acyltransferase from sunflower (Helianthus annuus L.).

A full-length cDNA encoding a putative diacylglycerol acyltransferase (DGAT; EC 2.3.1.20) was obtained from sunflower (Helianthus annuus L.) seeds. The 1524-bp open reading frame of this cDNA, designated as HaDGAT1, encodes a protein of 507 amino acids with a molecular mass of 58.5 kDa showing high homology to DGAT1 enzymes of other plants. The protein characters, such as a predicted structure with a long N-terminal hydrophilic domain followed by 9 transmembrane domains, acyl-CoA-binding signature, diacylglycerol (DAG)-binding and putative endoplasmic reticulum retrieval motifs (ER-DIR), also indicated that HaDGAT belongs to the DGAT1 family. HaDGAT1 is expressed in all plant tissues especially in developing seeds. Expression of recombinant HaDGAT1 in yeast showed an 1.76-fold increase of total fatty acids, especially unsaturated fatty acids such as palmitoleic acid (enhanced by 86.6%) and oleic acid (enhanced by 81.6%).

[Effects of pirenzepine on lens-induced myopia in the guinea-pig].

OBJECTIVE: To determine the efficacy of the M(1)-selective muscarinic antagonist, pirenzepine, in preventing lens-induced myopia in the guinea-pig and to study the mechanism and the possibility of treatment of myopia with pirenzepine. METHODS: Fifteen 4-week-old guinea-pigs were monocularly fitted with -10.00 D lenses for a period of 11 days. In Group I (n = 7), both eyes received topical administration of 0.24% saline vehicle as the controls. In Group II (n = 8), the lens-fitted eyes were topically treated with 10% pirenzepine, while the other eyes received the vehicle control. Ocular refraction and biometric measurements were collected on the first and the 11th days. All eyes were finally enucleated for histopathological examination to evaluate the possible toxic effects of pirenzepine. RESULTS: In Group I, 11 days of lens-fitting produced -2.45 D myopia (t = 3.141, P < 0.05) with 0.05 mm elongation of axial dimension (t = 2.500, P < 0.05) as compared to the contralateral eyes. There were no significantly differences of refractive error and axial dimensions between the experimental eyes and the controls in Group II. Histological examinations revealed no obviously toxic effects in the pirenzepine-treated eyes. CONCLUSIONS: Topical administration of the M(1)-selective muscarinic antagonist, pirenzepine, prevents lens-induced experimental myopia in guinea-pig by inhibiting the elongation of axial dimension with no obvious damage to the ocular tissues.