Endophytic fungi in buckwheat seeds: exploring links with flavonoid accumulation.

Buckwheat is a famous edible and medicinal coarse cereal which contain abundant of bioactive flavonoids, such as rutin. In this study, the composition and diversity of endophytic fungi in eight different buckwheat seeds were analyzed by high-throughput sequencing of ITS rDNA. Results showed that, the fungal sequences reads were allocated to 272 OTUs, of them, 49 OTUs were shared in eight buckwheat seeds. These endophytic fungi could be classified into 6 phyla, 19 classes, 41 orders, 79 families, 119 genera, and 191 species. At genus level, Alternaria sp. was the domain fungal endophyte. Besides, fungal endophytes belonged to the genera of Epicocum, Cladosporium, Botrytis, Filbobasidium, Stemphylium, and Vishniacozyma were highly abundant in buckwheat seeds. The total flavonoids and rutin contents in tartary buckwheat cultivars (CQ, XQ, CH, K2) were much higher than those in common buckwheat cultivars (HT, T2, T4, T8). For tartary buckwheat cultivars, the total flavonoids and rutin contents were ranging from 2.6% to 3.3% and 0.9% to 1.3%, respectively. Accordingly, the tartary buckwheat samples displayed stronger antioxidant activity than the common buckwheat. Spearman correlation heat map analysis was successfully found that certain fungal species from the genera of Alternaria, Botryosphaeria, Colletorichum and Diymella exhibited significant positive correlation with flavonoids contents. Results of this study preliminary revealed the fungi-plant interaction relationship at secondary metabolite level, and could provide novel strategy for increasing the flavonoids accumulation of buckwheat seeds, as well as improving their quality.

A Novel Conserved Linear Neutralizing Epitope on the Receptor-Binding Domain of the SARS-CoV-2 Spike Protein.

The continuous emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made it challenging to develop broad-spectrum prophylactic vaccines and therapeutic antibodies. Here, we have identified a broad-spectrum neutralizing antibody and its highly conserved epitope in the receptor-binding domain (RBD) of the spike protein (S) S1 subunit of SARS-CoV-2. First, nine monoclonal antibodies (MAbs) against the RBD or S1 were generated; of these, one RBD-specific MAb, 22.9-1, was selected for its broad RBD-binding abilities and neutralizing activities against SARS-CoV-2 variants. An epitope of 22.9-1 was fine-mapped with overlapping and truncated peptide fusion proteins. The core sequence of the epitope, 405D(N)EVR(S)QIAPGQ414, was identified on the internal surface of the up-state RBD. The epitope was conserved in nearly all variants of concern of SARS-CoV-2. MAb 22.9-1 and its novel epitope could be beneficial for research on broad-spectrum prophylactic vaccines and therapeutic antibody drugs. IMPORTANCE The continuous emergence of new variants of SARS-CoV-2 has caused great challenge in vaccine design and therapeutic antibody development. In this study, we selected a broad-spectrum neutralizing mouse monoclonal antibody which recognized a conserved linear B-cell epitope located on the internal surface of RBD. This MAb could neutralize all variants until now. The epitope was conserved in all variants. This work provides new insights in developing broad-spectrum prophylactic vaccines and therapeutic antibodies.

Comprehensive mapping of antigenic linear B-cell epitopes on K205R protein of African swine fever virus with monoclonal antibodies.

African swine fever virus causes an acute, highly contagious swine disease with high mortality, leading to enormous losses in the pig industry. The K205R, a nonstructural protein of African swine fever virus, is abundantly expressed in the cytoplasm of infected cells at the early stage of infection and induces a strong immune response. However, to date, the antigenic epitopes of this immunodeterminant have not been characterized. In the present study, the K205R protein was expressed in a mammalian cell line and purified using Ni-affinity chromatography. Furthermore, three monoclonal antibodies (mAbs; 5D6, 7A8, and 7H10) against K205R were generated. Indirect immunofluorescence assay and western blot results showed that all three mAbs recognized native and denatured K205R in African swine fever virus (ASFV)-infected cells. To identify the epitopes of the mAbs, a series of overlapping short peptides were designed and expressed as fusion proteins with maltose-binding protein. Subsequently, the peptide fusion proteins were probed with monoclonal antibodies using western blot and enzyme-linked immunosorbent assay. The three target epitopes were fine-mapped; the core sequences of recognized by the mAbs 5D6, 7A8, and 7H10 were identified as 157FLTPEIQAILDE168, 154REKFLTP160, and 136PTNAMFFTRSEWA148, respectively. Probing with sera from ASFV-infected pigs in a dot blot assay demonstrated that epitope 7H10 was the immunodominant epitope of K205R. Sequence alignment showed that all epitopes were conserved across ASFV strains and genotypes. To our knowledge, this is the first study to characterize the epitopes of the antigenic K205R protein of ASFV. These findings may serve as a basis for the development of serological diagnostic methods and subunit vaccines.

[Effects of gestational diabetes mellitus on gut microbiota of 3-month-old infants: a prospective control study].

OBJECTIVE: To explore the effect of gestational diabetes mellitus on the gut microbiota of their offsprings, the gut microbiota of 3-month-old infants whose mothers diagnosed with and without gestational diabetes mellitus(GDM) was compared. METHODS: Pregnant women and their 3-month-old infants who were examined, delivered and follow-up visited in a county in Hebei Province from June 2016 to December 2019 were included in our study. The pregnants and their infants with result of fasting venous blood glucose≥5.1 mmol/L in the second or third trimester were included in GDM group. Fecal samples of 3-month-old infants were collected and 16 S rDNA high-throughput sequencing technology was used to explore the change of gut microbiota. RESULTS: A total of 48 pairs of subjects were included, 16 in GDM group and 32 in control group. Comparison of gut microbiota diversity: analysis of the Alpha diversity index showed that the Observed Species index, margalef index and menhinick index of GDM group were(141.4±17.2), (13.66±1.66) and(0.83±0.10), respectively, which were significantly lower than that of control group(154.9±21.7), (15.00±2.11) and(0.91±0.13), respectively. Sequence analysis: at phylum level, the abundance of the Firmicutes, Bacteroidetes, Actinobacteria and Proteobacteria were 54.28(47.84), 23.58(23.48), 11.20(30.99) and 0.12(0.07), respectively, while the control group were 42.05(36.23), 29.64(21.30), 9.31(15.82) and 0.15(10.14), respectively. The two groups were mainly composed of these 4 phyla and Actinobacteria was the most abundant. At genus level, there were mainly Bifidobacteria, lactobacillus, Enterobacteria, Bacteroidales and Clostridiales in both groups. The abundance of Erysipelotrichales in GDM group(0.01(0.01)) was significantly lower than that in control group(0.04(0.06))(P<0.05). The abundance of Micrococcales in GDM group(0.13(0.24) was significantly lower than that in control group(0.29(0.78))(P<0.05). PCoA analysis showed that the gut microbiota structure of GDM group and control group was similar. LEfSe analysis showed Erysipelatoclostridium was significantly increased in control group(P<0.05). CONCLUSION: GDM can reduce the diversity and richness of gut microbiota of 3-month-old infants and has no significant effect on the phylum level but has effect on some genus level. It suggests that GDM may still have some potential effect on slightly elder infants.

De Novo Assembly of a Sarcocarp Transcriptome Set Identifies AaMYB1 as a Regulator of Anthocyanin Biosynthesis in Actinidia arguta var. purpurea.

The kiwifruit (Actinidia arguta var. purpurea) produces oval shaped fruits containing a slightly green or mauve outer exocarp and a purple-flesh endocarp with rows of tiny black seeds. The flesh color of the fruit results from a range of anthocyanin compounds, and is an important trait for kiwifruit consumers. To elucidate the molecular mechanisms involved in anthocyanin biosynthesis of the sarcocarp during A. arguta fruit development, de novo assembly and transcriptomic profile analyses were performed. Based on significant Gene Ontology (GO) biological terms, differentially expressed genes were identified in flavonoid biosynthetic and metabolic processes, pigment biosynthesis, carbohydrate metabolic processes, and amino acid metabolic processes. The genes closely related to anthocyanin biosynthesis, such as phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and anthocyanidin synthase (ANS), displayed significant up-regulation during fruit development according to the transcriptomic data, which was further confirmed by qRT-PCR. Meanwhile, a series of transcription factor genes were identified among the DEGs. Through a correlation analysis. AaMYB1 was found to be significantly correlated with key genes of anthocyanin biosynthesis, especially with CHS. Through a transient expression assay, AaMYB1 induced anthocyanin accumulation in tobacco leaves. These data provide an important basis for exploring the related mechanisms of sarcocarp anthocyanin biosynthesis in A. arguta. This study will provide a strong foundation for functional studies on A. arguta and will facilitate improved breeding of A. arguta fruit.

Chemical Profile, Antimicrobial and Antioxidant Activity Assessment of the Crude Extract and Its Main Flavonoids from Tartary Buckwheat Sprouts.

The purpose of this study was to investigate the major flavonoids content and bioactivities of Tartary buckwheat sprouts. The crude methanol extract (ME) of Tartary buckwheat sprouts was abundant in flavonoids, and six major flavonoids, including isoorientin, vitexin, isovitexin, rutin, quercetin, and kaemferol were successfully determined from the sprouts by the high-performance liquid chromatography (HPLC) method. Generally, the flavonoid content of buckwheat sprouts was in the order of rutin > quercetin > isovitexin > vitexin> isoorientin > kaemferol. The highest rutin content of the ME and sprout cultures was 89.81 mg/g and 31.50 mg/g, respectively. Antibacterial activity results indicated the ME displayed notable inhibitory activity against the five tested bacteria, and its minimum inhibitory concentration (MIC) values ranged from 0.8 mg/mL to 3.2 mg/mL. Among the six flavonoids, quercetin was the most active compound, which exhibited strong activity against all tested bacteria except for E. coli and S. epidermidis, with its MIC values ranging from 0.2 mg/mL to 0.4 mg/mL. For the antifungal activity assay, the ME of Tartary buckwheat sprouts and four flavonoids could significantly inhibit the spore germination of two pathogenic fungi, and their inhibitory efficiency was concentration dependent. Quercetin was the most active one, which significantly inhibited the spore germination of F. oxysporum f. sp. vasinfectum and F. oxysporum f. sp. cucumerinum, and its median effective inhibitory concentration (IC50) value was 42.36 and 32.85 µg/mL, respectively. The antioxidant activity results showed that quercetin, kaemferol, and rutin displayed excellent antioxidant activity in the DPPH radical scavenging test, and their IC50 value was calculated as 5.60, 16.23, and 27.95 µg/mL, respectively. This is the first report on the antimicrobial activity of the crude extract of Tartary buckwheat sprouts. These results indicated that the methanol extract of Tartary buckwheat sprouts could be used as a potential antimicrobial or antioxidant agent in the future.

[Spatiotemporal dynamics of soil salinity in the Yellow River Delta under the impacts of hydrology and climate.] / 水文气候影响下黄河三角洲土壤盐分时空动态.

In recent years, soil salinization in the Yellow River Delta under the effects of hydrology, climate and human activities have become increasingly prominent. Based on the 20 Landsat series images of Hekou, Kenli, Dongying districts and Lijin County of Dongying City selected from 1985 to 2018, numerical regression correction method was used to perform image spectral consistency conversion. The partial least squares regression method was used to construct quantitative inversion models of soil salt content. The soil salt content of the study area were retrieved by the best salt prediction model. The temporal and spatial characteristics of soil salt changes in the Yellow River Delta were analyzed. The results showed that the soil salt inversion model constructed with 10 sensitive spectral indices performed higher prediction accuracy, with coefficient of determination R2=0.769 and RMSE=1.125 for calibration, R2=0.752 and RMSE=1.203 for validation, and relative prediction deviation (RPD)=2.08. Using the measured soil salt data in 2016 to verify the inversion accuracy of the model, the correlation between the measured value and the inverted value was 0.7279. The model was used to map the soil salinity of the Yellow River Delta based on 20 images from 1985 to 2018. The abnormal soil salinity retrieval values was all less than 10%. During the study period, the soil salinity showed an overall trend of rising first and then falling which was lowest in 1985 (3.14 g·kg-1) and highest in 1995 (5.86 g·kg-1). Spatially, the area of heavily saline soil and saline soil in the study area decreased, and that of mildly and moderately saline soil significantly increased (66.6%). The total area of saline soil showed an increasing trend. The effects of hydrological and climatic conditions on soil salinity exhibited hysteresis. The increases of temperature promoted soil salinity, with the relationship between the soil salinity and the average temperatures in the past six months and one year being significantly correlated (R=0.507 and 0.538). Soil salinity did not correlate with regional precipitation, and was most affected by the Yellow River streamflow in the previous season (R=-0.543).

Protocatechuic Aldehyde Represses Proliferation and Migration of Breast Cancer Cells through Targeting C-terminal Binding Protein 1.

PURPOSE: C-terminal binding protein 1 (CtBP1) is a transcriptional co-repressor that is overexpressed in many cancers. CtBP1 transcriptionally represses a broad array of tumor suppressors, which promotes cancer cell proliferation, migration, invasion, and resistance to apoptosis. Recent studies have demonstrated that CtBP1 is a potential target for cancer therapy. This study was designed to screen for compounds that potentially target CtBP1. METHODS: Using a structure-based virtual screening for CtBP1 inhibitors, we found protocatechuic aldehyde (PA), a natural compound found in the root of a traditional Chinese herb, Salvia miltiorrhiza, that directly binds to CtBP1. Microscale thermophoresis assay was performed to determine whether PA and CtBP1 directly bind to each other. Further, clustered regularly interspaced short palindromic repeats associated Cas9 nuclease-mediated CtBP1 knockout in breast cancer cells was used to validate the CtBP1 targeting specificity of PA. RESULTS: Functional studies showed that PA repressed the proliferation and migration of breast cancer cells. Furthermore, PA elevated the expression of the downstream targets of CtBP1, p21 and E-cadherin, and decreased CtBP1 binding affinity for the promoter regions of p21 and E-cadherin in breast cancer cells. However, PA did not affect the expression of p21 and E-cadherin in the CtBP1 knockout breast cancer cells. In addition, the CtBP1 knockout breast cancer cells showed resistance to PA-induced repression of proliferation and migration. CONCLUSION: Our findings demonstrated that PA directly bound to CtBP1 and inhibited the growth and migration of breast cancer cells through CtBP1 inhibition. Structural modifications of PA are further required to enhance its binding affinity and selectivity for CtBP1.

Association between the PON1 Q192R polymorphism and coronary heart disease in Chinese: A meta-analysis.

BACKGROUND: The relation has not been reported consistently between the PON1 Q192R polymorphism and coronary heart disease (CHD). To clarify the discrepancy, we performed the present meta-analysis to evaluate the association between the PON1 gene Q192R polymorphism and CHD risk in Chinese population. METHODS: We conducted a comprehensive search of the PubMed, EMBASE, and China National Knowledge Infrastructure databases for all available case-control studies. Two reviewers independently selected studies. Data were analyzed by STATA software package v 12.0. RESULTS: Thirteen studies investigating the association between the PON1 Q192R polymorphism and risk of CHD were selected in this meta-analysis with 4353 cases and 4882 controls. The association between the PON1 Q192R polymorphism and CHD is statistically significant under the recessive genetic model (R/R vs Q/R + Q/Q, odds ratio [OR] = 1.111, 95% confidence interval [CI] = 1.017-1.214). We observed no statistical association between PON1 Q192R polymorphism and risk of CHD under allele model (R vs Q, OR = 1.087, 95% CI = 0.976-1.209), homozygous model (RR vs QQ, OR = 1.192, 95% CI = 0.949-1.496), and dominant genetic model (Q/R + R/R vs Q/Q, OR = 1.127, 95% CI = 0.938-1.354). CONCLUSION: This meta-analysis suggests that the PON1 Q192R polymorphism has a weak association with CHD risk in Chinese.

Carbonization of Fe-Based Metal Organic Frameworks with Mesoporous Structure as Electrocatalyst for Catalysis of Oxygen to Hydrogen Peroxide.

H2O2 production from electron reduction of oxygen (O2) is considered to be a potential alternative to the current anthraquinone process. Herein, we reported a mesoporous catalyst with iron-carboxylate metal-organic framework (MOF) as precursors to catalyze O2 to hydrogen peroxide (H2O2). Iron-carboxylate MOF (Fe-MOF) was synthesized by the novel cetyltrimethylammonium bromide (CTAB)-citric acid (CA) double-template method. The SEM and SAXD results revealed octahedral structure of the nanoparticles, as well as the presence of mesopores in the Fe-MOF, while the molar ratio 2.03 of CTAB to CA that resulted in the largest value (0.914 cm3g-1) of the mesopores in the Fe-MOFs. The pyrolysis of Fe-MOF with the largest amount of mesopores resulted in its carbonization and produced γ-Fe2O3@carbon material, significantly reduced the BET surface area from 3036 m2 g-1 to 387 m2 g-1, but increased the average pore diameter up to 5.78 nm and disintegrated their octahedral structures to an irregular morphology of Fe-MOF (550), and modified the carbon matrix with trace oxygen and metal oxides. The γ-Fe2O3@carbon material possessed mesoporous structure, with predominant graphitic carbon in the matrix (graphite to amorphous carbon ratio 0.79), which contributed to increased potential for electron reduction of O2 through a 2e- electron transfer pathway.

Effects of Polysaccharide Elicitors from Endophytic Fusarium oxysporum Fat9 on the Growth, Flavonoid Accumulation and Antioxidant Property of Fagopyrum tataricum Sprout Cultures.

The purpose of this study was to evaluate the effects of four different fungal polysaccharides, named water-extracted mycelia polysaccharide (WPS), sodium hydroxide-extracted mycelia polysaccharide (SPS), hydrochloric-extracted mycelia polysaccharide (APS), and exo-polysaccharide (EPS) obtained from the endophytic Fusarium oxysporum Fat9 on the sprout growth, flavonoid accumulation, and antioxidant capacity of tartary buckwheat. Without visible changes in the appearance of the sprouts, the exogenous polysaccharide elicitors strongly stimulated sprout growth and flavonoid production, and the stimulation effect was closely related with the polysaccharide (PS) species and its treatment dosage. With application of 200 mg/L of EPS, 200 mg/L of APS, 150 mg/L of WPS, or 100 mg/L of SPS, the total rutin and quercetin yields of buckwheat sprouts were significantly increased to 41.70 mg/(100 sprouts), 41.52 mg/(100 sprouts), 35.88 mg/(100 sprouts), and 32.95 mg/(100 sprouts), respectively. This was about 1.11 to 1.40-fold compared to the control culture of 31.40 mg/(100 sprouts). Moreover, the antioxidant capacity of tartary buckwheat sprouts was also enhanced after treatment with the four PS elicitors. Furthermore, the present study revealed the polysaccharide elicitation that caused the accumulation of functional flavonoid by stimulating the phenylpropanoid pathway. The application of beneficial fungal polysaccharide elicitors may be an effective approach to improve the nutritional and functional characteristics of tartary buckwheat sprouts.

Prognostic Superiority of Log Odds of Positive Lymph Nodes in Stage 3 Colorectal Cancer.

Objective To evaluate the prognostic value of the log odds of positive lymph nodes (LODDS) in stage 3 colorectal cancer (CRC) patients who have undergone curative resection. Methods We performed a retrospective review of 175 stage 3 CRC patients who underwent curative resection in Peking Union Medical College Hospital from 2005 to 2012. Patients were categorized respectively according to the AJCC/UICC N grade,the metastatic lymph node ratio (LNR),and the ratio of their LODDS. The relationship between the N grade,LNR,LODDS,and overall survival (OS) rates were assessed.Results The five-year disease-free survival (DFS) was significantly different among stage 3 CRC patients in different N grade (Χ(2)=33.1,P=0.000),LNR (Χ(2)=14.3,P=0.001),and LODDS (Χ(2)=14.9,P=0.001). Univariate analysis showed that TNM stage (Χ(2)=27.0,P=0.000),cancerous node(Χ(2)=3.6,P=0.040),N grade (Χ(2)=33.1,P=0.000),LNR (Χ(2)=14.3,P=0.001),and LODDS (Χ(2)=30.4,P=0.000) were related to OS. Multivariate analysis indicated that TNM stage (HR:1.84,95%CI:1.59～6.29,P=0.001) and LODDS classification (HR:1.34,95%CI:1.01～1.80,P=0.047) were independent prognostic factors for OS in stage 3 CRC patients. Conclusion LODDS is a good prognostic indicator in stage 3 CRC patients who have undergone curative resection.

Laparoscopic restorative proctocolectomy with ileal pouch-anal anastomosis for Peutz-Jeghers syndrome with synchronous rectal cancer.

We report on a patient diagnosed with Peutz-Jeghers syndrome (PJS) with synchronous rectal cancer who was treated with laparoscopic restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). PJS is an autosomal dominant syndrome characterized by multiple hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and increased risks of gastrointestinal and nongastrointestinal cancer. This report presents a patient with a 20-year history of intermittent bloody stool, mucocutaneous pigmentation and a family history of PJS, which together led to a diagnosis of PJS. Moreover, colonoscopy and biopsy revealed the presence of multiple serried giant pedunculated polyps and rectal adenocarcinoma. Currently, few options exist for the therapeutic management of PJS with synchronous rectal cancer. For this case, we adopted an unconventional surgical strategy and ultimately performed laparoscopic restorative proctocolectomy with IPAA. This procedure is widely considered to be the first-line treatment option for patients with ulcerative colitis or familial adenomatous polyposis. However, there are no previous reports of treating PJS patients with laparoscopic IPAA. Since the operation, the patient has experienced no further episodes of gastrointestinal bleeding and has demonstrated satisfactory bowel control. Laparoscopic restorative proctocolectomy with IPAA may be a safe and effective treatment for patients with PJS with synchronous rectal cancer.

Genetic properties of endemic Chinese porcine epidemic diarrhea virus strains isolated since 2010.

Acute diarrhea outbreaks caused by porcine epidemic diarrhea virus (PEDV) have been observed in various pig-breeding provinces of China since December 2010. Endemic strains of PEDV were isolated from different areas, and the complete genome sequences of 10 isolates were determined. Our objective in this study was to genetically characterize current Chinese field isolates of PEDV to better understand their epidemiology and genetic diversity. Sequence analysis showed that 10 post-2010 isolates shared high homology with each other and were always clustered together with the virulent DR13 strains (South Korea) and/or one earlier Chinese strain, CH-S, in phylogenetic analysis. All post-2010 isolates possessed common sequence changes in each gene. Our results suggest that current Chinese PEDV isolates originated from either South Korean and/or Chinese ancestors that underwent some genetic variation, thereby forming a new PEDV genotype in China.

Complete genome sequence of a variant porcine epidemic diarrhea virus strain isolated in central china.

We report here the complete genome sequence of the porcine epidemic diarrhea virus strain CH/ZMDZY/11 isolated from central China. Our data, together with sequence data of porcine epidemic diarrhea virus (PEDV) isolates from other parts in China, will help to understand better the epidemiology and genetic diversity of PEDV field isolates in China.

[Effects of herbivorous insect stress on the growth and yield-related traits of insect-resistant transgenic rice].

A field experiment was conducted to test the effects of high and low herbivorous insect stresses on the growth, development and yield-related traits of insect-resistant transgenic rice. Three Bt transgenic rice Bt63, R1 and R2 were selected as the test materials, and non-transgenic rice Shanyou63 was taken as the control. The differences in the vegetative growth, seed-setting, and stem borer resistance between transgenic and non-transgenic rice were compared. Under herbivorous insect stress, the transgenic rice fully displayed the stem borer-resistance of exogenous gene. Under the high stress, the stem borer-damaged degree of the three transgenic rice lines was much lower than that of the control. The plant height, tillers per plant, aboveground fresh mass, panicle length, panicle fresh mass, productive panicles per plant, filled grains per plant, grain mass per plant, seed setting rate, and 1000-grain mass of the three transgenic rice lines excelled the control, but had no significant differences except plant height, tillers per plant, and panicle length. Therefore, introducing exogenous Bt gene into rice had no negative effect on rice seed-setting, and high herbivorous insect stress had less impacts on transgenic rice yield.

[Safety and efficacy of prophylactic single antibiotics administration in selective open colorectal surgery].

OBJECTIVE: To investigate the safety and efficacy of prophylactic single antibiotic administration in selective open colorectal surgery. METHODS: Two hundred and seventy-five patients undergoing selective open colorectal surgery in the Peking Union Medical College Hospital from October 2009 to October 2011 were retrospectively reviewed. Prophylatic single antibiotic administration was used by intravenous infusion 30-60 min before incision. No antibiotics would be given after operation if there was no surgical site infection(SSI). According to the incidence of postoperative SSI, unexplained use of antibiotics, anastomotic leakage and distant-site infection, the clinical outcome was assessed to be prophylactic success, prophylactic failure or distant-site infection, respectively. RESULTS: There was no intraoperative or postoperative antibiotics related drug anaphylaxis in all the 275 patients. By prophylactic single antibiotic administration, there were prophylactic success in 243 patients(88.4%,243/275), prophylactic failure in 23(8.4%,23/275), distant-site infection in 9(3.3%,9/275). In the 23 patients with failed prophylaxis, there were SSI in 13(4.7%,13/275) patients, postoperative use of broad-spectrum antibiotics for unexplained fever in 2(0.7%,2/275), postoperative anastomotic leakage in 8(3.6%,8/222). CONCLUSION: Prophylactic single antibiotic administration in selective open colorectal surgery is safe and effective.