The Association of Serum Complement C1q with Coronary Artery Disease: A Systematic Review and Meta-Analysis.

Background: Coronary artery disease (CAD) is one of the leading causes of death in middle-aged and elderly people, and its incidence has been increasing in recent years. An in-depth understanding of the pathogenesis of CAD is important to ensure the health of CAD patients. Objective: To analyze the association of serum complement C1q with CAD," you could say something like "The objective of this meta-analysis is to investigate the relationship between serum complement C1q levels and the presence of CAD, aiming to provide insights for clinical diagnosis and treatment. Methods: Relevant studies on C1q and CAD were searched in PubMed, Web of Science and other literature databases. Two research team members independently cross-screened the literature according to the inclusion-exclusion criteria and assessed the literature quality. RevMan5.3 software was used for statistical analysis. Results: Three references were finally included, all of which had a Newcastle-Ottawa Scale (NOS) score ≥6, indicating high quality. A total of 2065 subjects were studied, including 1249 in the experimental group (CAD patients) and 816 in the control group (healthy population). Through the meta-analysis, it was found that the experimental group (CAD patients) had higher serum C1q than the control group (healthy controls) (P < .05). According to subgroup analysis, age, sex, sample size, diabetes mellitus (with/without), and serum complement C1q detection methods were not factors affecting the heterogeneity of the literature, and more data are needed for verification. Validation analysis with the fixed-effect model also showed higher C1q expression in the experimental group (P < .05). The graph of the funnel plot was basically symmetrical, suggesting low publication bias. Conclusions: Serum complement C1q is elevated in CAD patients, but its mechanism of action may have a dual effect, but further research is needed to understand its precise role and clinical implications.

A spatially resolved single-cell genomic atlas of the adult human breast.

The adult human breast is comprised of an intricate network of epithelial ducts and lobules that are embedded in connective and adipose tissue1-3. Although most previous studies have focused on the breast epithelial system4-6, many of the non-epithelial cell types remain understudied. Here we constructed the comprehensive Human Breast Cell Atlas (HBCA) at single-cell and spatial resolution. Our single-cell transcriptomics study profiled 714,331 cells from 126 women, and 117,346 nuclei from 20 women, identifying 12 major cell types and 58 biological cell states. These data reveal abundant perivascular, endothelial and immune cell populations, and highly diverse luminal epithelial cell states. Spatial mapping using four different technologies revealed an unexpectedly rich ecosystem of tissue-resident immune cells, as well as distinct molecular differences between ductal and lobular regions. Collectively, these data provide a reference of the adult normal breast tissue for studying mammary biology and diseases such as breast cancer.

A spatially resolved single cell genomic atlas of the adult human breast.

The adult human breast comprises an intricate network of epithelial ducts and lobules that are embedded in connective and adipose tissue. While previous studies have mainly focused on the breast epithelial system, many of the non-epithelial cell types remain understudied. Here, we constructed a comprehensive Human Breast Cell Atlas (HBCA) at single-cell and spatial resolution. Our single-cell transcriptomics data profiled 535,941 cells from 62 women, and 120,024 nuclei from 20 women, identifying 11 major cell types and 53 cell states. These data revealed abundant pericyte, endothelial and immune cell populations, and highly diverse luminal epithelial cell states. Our spatial mapping using three technologies revealed an unexpectedly rich ecosystem of tissue-resident immune cells in the ducts and lobules, as well as distinct molecular differences between ductal and lobular regions. Collectively, these data provide an unprecedented reference of adult normal breast tissue for studying mammary biology and disease states such as breast cancer.

Preneoplastic stromal cells promote BRCA1-mediated breast tumorigenesis.

Women with germline BRCA1 mutations (BRCA1+/mut) have increased risk for hereditary breast cancer. Cancer initiation in BRCA1+/mut is associated with premalignant changes in breast epithelium; however, the role of the epithelium-associated stromal niche during BRCA1-driven tumor initiation remains unclear. Here we show that the premalignant stromal niche promotes epithelial proliferation and mutant BRCA1-driven tumorigenesis in trans. Using single-cell RNA sequencing analysis of human preneoplastic BRCA1+/mut and noncarrier breast tissues, we show distinct changes in epithelial homeostasis including increased proliferation and expansion of basal-luminal intermediate progenitor cells. Additionally, BRCA1+/mut stromal cells show increased expression of pro-proliferative paracrine signals. In particular, we identify pre-cancer-associated fibroblasts (pre-CAFs) that produce protumorigenic factors including matrix metalloproteinase 3 (MMP3), which promotes BRCA1-driven tumorigenesis in vivo. Together, our findings demonstrate that precancerous stroma in BRCA1+/mut may elevate breast cancer risk through the promotion of epithelial proliferation and an accumulation of luminal progenitor cells with altered differentiation.

scEpiLock: A Weakly Supervised Learning Framework for cis-Regulatory Element Localization and Variant Impact Quantification for Single-Cell Epigenetic Data.

Recent advances in single-cell transposase-accessible chromatin using a sequencing assay (scATAC-seq) allow cellular heterogeneity dissection and regulatory landscape reconstruction with an unprecedented resolution. However, compared to bulk-sequencing, its ultra-high missingness remarkably reduces usable reads in each cell type, resulting in broader, fuzzier peak boundary definitions and limiting our ability to pinpoint functional regions and interpret variant impacts precisely. We propose a weakly supervised learning method, scEpiLock, to directly identify core functional regions from coarse peak labels and quantify variant impacts in a cell-type-specific manner. First, scEpiLock uses a multi-label classifier to predict chromatin accessibility via a deep convolutional neural network. Then, its weakly supervised object detection module further refines the peak boundary definition using gradient-weighted class activation mapping (Grad-CAM). Finally, scEpiLock provides cell-type-specific variant impacts within a given peak region. We applied scEpiLock to various scATAC-seq datasets and found that it achieves an area under receiver operating characteristic curve (AUC) of ~0.9 and an area under precision recall (AUPR) above 0.7. Besides, scEpiLock's object detection condenses coarse peaks to only ⅓ of their original size while still reporting higher conservation scores. In addition, we applied scEpiLock on brain scATAC-seq data and reported several genome-wide association studies (GWAS) variants disrupting regulatory elements around known risk genes for Alzheimer's disease, demonstrating its potential to provide cell-type-specific biological insights in disease studies.

InsuLock: A Weakly Supervised Learning Approach for Accurate Insulator Prediction, and Variant Impact Quantification.

Mapping chromatin insulator loops is crucial to investigating genome evolution, elucidating critical biological functions, and ultimately quantifying variant impact in diseases. However, chromatin conformation profiling assays are usually expensive, time-consuming, and may report fuzzy insulator annotations with low resolution. Therefore, we propose a weakly supervised deep learning method, InsuLock, to address these challenges. Specifically, InsuLock first utilizes a Siamese neural network to predict the existence of insulators within a given region (up to 2000 bp). Then, it uses an object detection module for precise insulator boundary localization via gradient-weighted class activation mapping (~40 bp resolution). Finally, it quantifies variant impacts by comparing the insulator score differences between the wild-type and mutant alleles. We applied InsuLock on various bulk and single-cell datasets for performance testing and benchmarking. We showed that it outperformed existing methods with an AUROC of ~0.96 and condensed insulator annotations to ~2.5% of their original size while still demonstrating higher conservation scores and better motif enrichments. Finally, we utilized InsuLock to make cell-type-specific variant impacts from brain scATAC-seq data and identified a schizophrenia GWAS variant disrupting an insulator loop proximal to a known risk gene, indicating a possible new mechanism of action for the disease.

Integrated Single-Cell Transcriptomics and Chromatin Accessibility Analysis Reveals Regulators of Mammary Epithelial Cell Identity.

The mammary epithelial cell (MEC) system is a bilayered ductal epithelium of luminal and basal cells, maintained by a lineage of stem and progenitor populations. Here, we used integrated single-cell transcriptomics and chromatin accessibility analysis to reconstruct the cell types of the mouse MEC system and their underlying gene regulatory features in an unbiased manner. We define differentiation states within the secretory type of luminal cells, which forms a continuous spectrum of general luminal progenitor and lactation-committed progenitor cells. By integrating single-cell transcriptomics and chromatin accessibility landscapes, we identify cis- and trans-regulatory elements that are differentially activated in the specific epithelial cell types and our newly defined luminal differentiation states. Our work provides a resource to reveal cis/trans-regulatory elements associated with MEC identity and differentiation that will serve as a reference to determine how the chromatin accessibility landscape changes during breast cancer.

Defining Epidermal Basal Cell States during Skin Homeostasis and Wound Healing Using Single-Cell Transcriptomics.

Our knowledge of transcriptional heterogeneities in epithelial stem and progenitor cell compartments is limited. Epidermal basal cells sustain cutaneous tissue maintenance and drive wound healing. Previous studies have probed basal cell heterogeneity in stem and progenitor potential, but a comprehensive dissection of basal cell dynamics during differentiation is lacking. Using single-cell RNA sequencing coupled with RNAScope and fluorescence lifetime imaging, we identify three non-proliferative and one proliferative basal cell state in homeostatic skin that differ in metabolic preference and become spatially partitioned during wound re-epithelialization. Pseudotemporal trajectory and RNA velocity analyses predict a quasi-linear differentiation hierarchy where basal cells progress from Col17a1Hi/Trp63Hi state to early-response state, proliferate at the juncture of these two states, or become growth arrested before differentiating into spinous cells. Wound healing induces plasticity manifested by dynamic basal-spinous interconversions at multiple basal transcriptional states. Our study provides a systematic view of epidermal cellular dynamics, supporting a revised "hierarchical-lineage" model of homeostasis.

Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR34/L98H/S297T/F495I Mutation.

The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR34/L98H/S297T/F495I mutation, but not among isolates with TR34/L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR34/L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres, which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus.

Upregulation of kallikrein­related peptidase 5 is associated with the malignant behavior of colorectal cancer.

Kallikrein-related peptidase 5 (KLK5) is a serine protease that has exhibited upregulated expression in numerous types of human cancer. The present study assessed KLK5 expression in colorectal cancer (CRC) tissues, in order to determine its association with clinicopathological data and prognosis. The mRNA and protein expression levels of KLK5 were detected using reverse transcription­quantitative polymerase chain reaction, immunohistochemistry and enzyme­linked immunosorbent assay, respectively. KLK5 expression was detected in 48 paraffin­embedded tumor tissue samples and corresponding tumor­free areas within the same specimens, 40 paired normal and CRC frozen tissues, and serum samples from 70 patients with CRC (including 38 serum samples taken pre­ and post­surgery) and 53 healthy individuals. The results demonstrated that KLK5 protein was strongly expressed in CRC; however, its expression was hardly detected in the matched normal mucosal tissue. The KLK5 mRNA expression levels were significantly upregulated in CRC tissues compared with the paired normal tissues, and were higher in Dukes' stage C/D cancer than in stage A/B (P<0.001). Furthermore, sera from patients with CRC exhibited increased KLK5 levels, as compared with that of healthy volunteers (878.02 vs. 391.07 pg/ml; P<0.001). Serum KLK5 levels were also significantly higher in patients prior to surgery compared with post­surgery (909.48±536.72 vs. 644.00±522.87 pg/ml; P<0.001). In addition, increased serum KLK5 levels were associated with CRC lymph node or distant metastasis (P=0.003), tumor­lymph node­metastasis stage (P=0.004), and Dukes' stage (P=0.005). The results of the present study indicated that the mRNA and protein expression levels of KLK5 were significantly upregulated in CRC tissues and sera, and were associated with an advanced tumor stage. Further studies may identify KLK5 as a biomarker of CRC recurrence or treatment response.

Epidemiology and Molecular Characterizations of Azole Resistance in Clinical and Environmental Aspergillus fumigatus Isolates from China.

Azole resistance in Aspergillus fumigatus has emerged as a worldwide public health problem. We sought here to demonstrate the occurrence and characteristics of azole resistance in A. fumigatus from different parts of China. A total of 317 clinical and 144 environmental A. fumigatus isolates from 12 provinces were collected and subjected to screening for azole resistance. Antifungal susceptibility, cyp51A gene sequencing, and genotyping were carried out for all suspected azole-resistant isolates and a subset of azole-susceptible isolates. As a result, 8 (2.5%) clinical and 2 (1.4%) environmental A. fumigatus isolates were identified as azole resistant. Five azole-resistant strains exhibit the TR34/L98H mutation, whereas four carry the TR34/L98H/S297T/F495I mutation in the cyp51A gene. Genetic typing and phylogenetic analysis showed that there was a worldwide clonal expansion of the TR34/L98H isolates, while the TR34/L98H/S297T/F495I isolates from China harbored a distinct genetic background with resistant isolates from other countries. High polymorphisms existed in the cyp51A gene that produced amino acid changes among azole-susceptible A. fumigatus isolates, with N248K being the most common mutation. These data suggest that the wide distribution of azole-resistant A. fumigatus might be attributed to the environmental resistance mechanisms in China.

Characteristics of qacA/B-positive Staphylococcus aureus isolated from patients and a hospital environment in China.

OBJECTIVES: This study was designed to demonstrate the characteristics of qacA/B-positive Staphylococcus aureus in China. METHODS: One hundred and forty-five MRSA and 178 MSSA from clinical specimens from seven hospitals in different regions of China, 70 MRSA from superficial sites of patients and 106 MRSA from environmental samples from an ICU were collected and screened for the presence of the qacA/B gene. The qacA/B-positive isolates and 72 randomly selected qacA/B-negative control isolates were further characterized by MLST, spa typing and detection of toxin genes, as well as antimicrobial and chlorhexidine susceptibility. SCCmec typing was conducted for MRSA. PFGE was conducted for qacA/B-positive isolates. RESULTS: Twenty-five (7.8%) of the 321 MRSA isolates harboured qacA/B, including 11 isolates from clinical specimens (7.6%), 12 isolates from patients' superficial sites (17.1%) and 2 isolates from an ICU environment (1.9%). Ten and five qacA/B-positive MRSA were identified as ST239-t030-MRSA-III and ST239-t037-MRSA-III, respectively. Six PFGE clusters and five singletons were identified among the 25 qacA/B-positive MRSA. Only one (0.6%) of the 178 MSSA isolates harboured qacA/B. qacA/B carriage in MRSA was statistically associated with spa-t037 and the presence of mupA. Compared with qacA/B-negative MRSA, the qacA/B-positive MRSA exhibited a lower susceptibility to chlorhexidine and higher resistance rates to clindamycin and trimethoprim/sulfamethoxazole. CONCLUSIONS: Carriage of qacA/B, although it had a low prevalence, might be the main reason for declining susceptibility to chlorhexidine in MRSA from Chinese patients and is probably associated with spa-t037 and the presence of the mupA gene.

Mutant prevention concentrations of levofloxacin, pazufloxacin and ciprofloxacin for A. baumannii and mutations in gyrA and parC genes.

Fluoroquinolones are antimicrobial agents that are widely used clinically, but the increasing resistance of Acinetobacter baumannii (A. baumannii) to these agents is a matter of concern. We investigated mutant prevention concentrations (MPCs) of three fluoroquinolones, levofloxacin (LVX), pazufloxacin (PAZ) and ciprofloxacin (CIP). We analyzed an A. baumannii standard strain (ATCC19606) for mutation prevention indices (MPIs), MPCs and mutant selection windows as well as MICs of CIP, PAZ and LVX and compared the derived values with 34 A. baumannii strains collected in hospitals. In addition, A. baumannii standard strain (ATCC19606) fluoroquinolone-resistant mutants were investigated for gyrA and parC gene mutations. MPCs of CIP, prevention antibiotics concentration and LVX for A. baumannii ATCC19606 were 12.8, 5.6 and 2.8 µg ml(-1) and their MPIs were 16, 8 and 4, respectively. Clinically isolated A. baumannii strains had CIP, PAZ and LVX MPC value ranges of 1-8, 1-16 and 0.5-2 µg ml(-1) and their MPIs were 8, 8 and 4 µg ml(-1). Single gyrA mutations (Ser(83)-Leu(83)) occurred in 18 resistant strains (48.7%) and single parC mutations (Ala(79)-Asp(79) or (Ser(80)-Leu(80)) occurred in 8 resistant strains (21.6%), whereas gyrA and parC double mutations occurred in 2 (5.4%) of the resistant strains. MPC and MPI values of LVX were lower than that of CIP and PAZ. Single gyrA and parC mutations accounted for the majority of mutations (n=24), whereas double mutations occurred only in two strains.

Characterization of Staphylococcus aureus from distinct geographic locations in China: an increasing prevalence of spa-t030 and SCCmec type III.

Staphylococcus aureus belongs to one of the most common bacteria causing healthcare and community associated infections in China, but their molecular characterization has not been well studied. From May 2011 to June 2012, a total of 322 non-duplicate S. aureus isolates were consecutively collected from seven tertiary care hospitals in seven cities with distinct geographical locations in China, including 171 methicillin sensitive S. aureus (MSSA) and 151 MRSA isolates. All isolates were characterized by spa typing. The presence of virulence genes was tested by PCR. MRSA were further characterized by SCCmec typing. Seventy four and 16 spa types were identified among 168 MSSA and 150 MRSA, respectively. One spa type t030 accounted for 80.1% of all MRSA isolates, which was higher than previously reported, while spa-t037 accounted for only 4.0% of all MRSA isolates. The first six spa types (t309, t189, t034, t377, t078 and t091) accounted for about one third of all MSSA isolates. 121 of 151 MRSA isolates (80.1%) were identified as SCCmec type III. pvl gene was found in 32 MSSA (18.7%) and 5 MRSA (3.3%) isolates, with ST22-MSSA-t309 as the most commonly identified strain. Compared with non-epidemic MRSA clones, epidemic MRSA clones (corresponding to ST239) exhibited a lower susceptibility to rifampin, ciprofloxacin, gentamicin and trimethoprim-sulfamethoxazole, a higher prevalence of sea gene and a lower prevalence of seb, sec, seg, sei and tst genes. The increasing prevalence of multidrug resistant spa-t030 MRSA represents a major public health problem in China.

The identification, typing, and antimicrobial susceptibility of Pseudomonas aeruginosa isolated from mink with hemorrhagic pneumonia.

The biological characteristics and molecular epidemiology of Pseudomonas aeruginosa associated with mink hemorrhagic pneumonia from Shandong province of eastern China were determined in this study. From 2010 to 2011, 30 mink P. aeruginosa isolates were identified from lung, fecal and feed samples of clinical cases and subjected to serotyping, antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) using SpeI. The P. aeruginosa isolates belonged to four serotypes-21 of type G, four of type I, three of type M, one of type B, and one non-typable strain. The strains were divided into four large groups as determined by PFGE. Isolates from the group 2 were highly homologous and were obtained from the same region as an epidemic. All of the isolates were sensitive to piperacillin, piperacillin/tazobactam, ceftazidime, cefepime, imipenem, amikacin, gentamicin and tobramycin and resistant to ampicillin, cefuroxime and cefuroxime axetil. A high frequency of resistance was found to ampicillin/sulbactam, cefazolin, cefotetan, ceftriaxone, nitrofurantoin, and trimethoprim/sulfamethoxazole (96.7%). Resistance to ticarcillin/clavulanic acid, ciprofloxacin and levofloxacin was less common (13.3%). There was no relationship between antibiotic resistance and serotype distribution of the isolates. The epidemic serotype of P. aeruginosa from the mink hemorrhagic pneumonia in Shandong province was type G, which was a clone of commonly found in this province. These findings reveal the genetic similarities and antimicrobial susceptibility profiles of P. aeruginosa from clinical cases of mink hemorrhagic pneumonia and will facilitate the prevention and control of the disease in Shandong province of China.

Pathogenic analysis of Vibrio alginolyticus infection in a mouse model.

Vibrio alginolyticus is a Gram-negative halophilic bacterium and has been recognized as an opportunistic pathogen to both humans and marine animals. So far, most studies have been focused on marine animals and few reports have been aimed at mammals, including human. In this study, we first established a mouse model to understand the pathogenic mechanism of V. alginolyticus infection. After infection via intraperitoneal injection, hematological and liver function indicators were evaluated and serum interleukin (IL)-1ß and IL-6 expression were detected by ELISA. Furthermore, we compared the virulence of two V. alginolyticus strains, ATCC17749T and E0666. The results demonstrated that V. alginolyticus infection causes robust lung and liver damage and induces changes in IL-1ß, IL-6, hematological, and liver indicators. In addition, the ATCC17749T strain appeared to be more virulent than the E0666 strain. Better understanding of the pathogenic mechanism of V. alginolyticus infection should guide effective prevention and therapy for V. alginolyticus infection.

Direct serum and tissue assay for EGFR mutation in non-small cell lung cancer by high-resolution melting analysis.

Biological therapy with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have noted promising outcomes for patients with non-small cell lung carcinoma (NSCLC), especially those with mutated EGFR. Tissue EGFR gene mutation testing can predict the benefit of taking a first-line EGFR-TKI, thus, allowing the physician to prescribe the most suitable therapy. Unfortunately, most lung cancer patients, especially NSCLC patients present with advanced disease that is surgically unresectable. The goal of this study was to develop high-resolution melting (HRM) assays to detect EGFR mutations in exons 18 to 21, compare their sensitivity and concordance to direct sequencing, and evaluate the feasibility and reliability of serum as a tissue alternate for routine EGFR mutation screening. EGFR mutations of 126 Formalin-Fixed Paraffin-Embedded (FFPE), 47 fresh frozen tissues and from 47 matched pre-operation serum specimens of NSCLC patients were screened by the HRM assays. EGFR mutations by HRM were confirmed through sequencing. We found 78 EGFR mutations in 70 FFPE tissues, 25 EGFR mutations in 24 fresh frozen tissues, with a mutation rate of 55.56% (70/126) and 51.06% (24/47), respectively. Most mutations were correctly identified by sequencing. EGFR mutations were detected in 22 serum samples from 24 tissue EGFR mutation-positive patients. The concordance rate between serum and tissue in EGFR mutation screening was 91.67%. We conclude that the HRM assay can provide convincing and valuable results both for serum and tissues samples, thus, it is suitable for routine serum EGFR mutation screening for NSCLC patients, especially those surgically unresectable.

Treatment of dairy wastewater by two-stage membrane operation with ultrafiltration and nanofiltration.

Treatment of dairy wastewater by a two-stage membrane process with ultrafiltration (UF) and nanofiltration (NF) was investigated. The results showed that the flux of UF was higher at pH = 4.6 than that at pH = 8 because the resistance of the fouling membrane was lower at the isoelectric point of protein (pH = 4.6) in UF operation. Protein rejection exceeded 99% by UF + NF operation. Lactose rejections were 98.5 and 54% for UF + NF90 and UF + NF270 respectively. Experiments on membrane cleaning showed that the fouling layer of UF and NF was mainly protein and casein which could be removed by aqueous NaOH with pH = 10. The result of long-term experiments showed that the chemical oxygen demand (COD) of NF90 permeates was below 70 mg/L consistently and the wastewater could be concentrated to 24% by a two-stage membrane process.

RGD-dependent mechanotransduction of suspension cultured Taxus cell in response to shear stress.

Plant cells cultured in bioreactors are strongly influenced by mechanical forces. However, the molecular mechanism of plant cell mechanoreception has maintained unclear. In animal cells, the Arg-Gly-Asp (RGD) motif can be found in proteins of the extracellular matrix. Integrins link the intracellular cytoskeleton of cells with the extracellular matrix by recognizing this RGD motif. Integrin has been demonstrated to function as an apparatus not only for adhesion but also for mechanotransduction. In plant cells, the molecules that mediate the structural continuity between wall and membrane are unknown. Here, we found that synthetic RGD peptide could dramatically reduce the level of phosphorylation of MAPK-like cascades that are activated by shear stress and reduce the alkalinization response, production of reactive oxygen species (ROS) and accumulation of phenolics by Taxus cuspidata cells during shear stress. These results implicate that a RGD recognition system may exist in Taxus cells and play an important role in signal transduction of shear stress. Although the Arabidopsis genome database shows that the plant seems to lack a homologue of animal integrin, plant cells may use other RGD-binding proteins to recognize the RGD motif. The correlative mechanism is discussed.

Nitric oxide mediates inactivation of glutathione S-transferase in suspension culture of Taxus cuspidata during shear stress.

The importance of nitric oxide (NO) in regulating plant cell responses to environmental stresses is becoming evident. Here the possible role of NO in suspension cultures of Taxus cuspidata under shear stress was investigated in a Couette-type shear reactor. It was found that shear stress with 190 s(-1) caused NO generation in 8 h. NO formation can be inhibited by N-nitro-L-arginine, a nitric oxide synthase inhibitor. Moreover, the activity of glutathione S-transferase (GST), a principal enzyme responsible for detoxification, decreased during shear stress. This inactivation partially recovered when NOS inhibitor or NO scavenger was added into cell cultures during shear stress. Treatment with reactive nitrogen species (RNS) also caused inactivation of GST in cells. The results indicate that NO plays a crucial role in GST inactivation in Taxus cuspidata cells under shear stress.