As a biocatalyst, laccase has been widely studied and applied in the papermaking industry. However, the low catalytic efficiency and poor stability of natural laccase limit its application in the pulping process. To develop the laccase with high activity and strong tolerance, we carried out directed evolution for modification of the laccase derived from Bacillus pumilus and screened out the mutants F282L/F306L and Q275P from the random mutant library by high-throughput screening. The specific activities of F282L/F306L and Q275P were 280.87 U/mg and 453.94 U/mg, respectively, which were 1.42 times and 2.30 times that of the wild-type laccase. Q275P demonstrated significantly improved thermal stability, with the relative activity 20% higher than that of the wild-type laccase after incubation at 40 ℃, 50 ℃, and 70 ℃ for 4 h. F282L/F306L and Q275P showed greater tolerance to metal ions and organic solvents than the wild-type laccase. The K_m value of the wild-type laccase was 374.97 μmo/L, and those of F282L/F306L and Q275P were reduced to 318.96 μmo/L and 360.71 μmo/L, respectively, which suggested that the substrate affinity of laccase was improved after mutation. The k_cat values of F282L/F306L and Q275P for the substrate ABTS were 574.00 s^-1 and 898.03 s^-1, respectively, which were 1.1 times and 1.7 times that of the wild-type laccase, indicating the improved catalytic efficiency. Q275P demonstrated better performance than the wild-type laccase in pulping, as manifested by the reduction of 0.82 in the Kappa number and the increases of 2.00% ISO, 7.8%, and 7.2% in whiteness, tensile index, and breaking length, respectively. This work lays a foundation for improving the adaptation of laccase to the environment of the papermaking industry.
Laccase/chemistry* ; Directed Molecular Evolution ; Enzyme Stability ; Bacillus pumilus/genetics* ; Mutation ; Biocatalysis ; Catalysis

  Objective  To investigate the predictive value of albumin-bilirubin (ALBI) score combined with liver function index and carcinoembryonic antigen (CEA) for liver metastasis of colorectal cancer.  Methods  We retrospectively analyzed the clinical data of patients with colorectal cancer who underwent surgical treatment in the Second Hospital & Clinical Medical Hospital, Lanzhou University from January 2016 to July 2021 and were followed up for 24 months. According to the follow-up results, the enrolled patients were divided into liver metastasis group and non-liver metastasis group, and were randomly divided into modeling group and validation group by a ratio of 2∶1. The risk factors of liver metastasis in the patients with colorectal cancer were analyzed. Lasso-Logistic regression was used to construct the prediction model. Bootstrap method was used for internal verification. Receiver operating characteristic curve, calibration curve and clinical decision curve were used to evaluate the reliability of the prediction model. Finally, a nomogram was drawn to show the prediction results.  Results  A total of 195 patients who met the inclusion and exclusion criteria were enrolled, including 130 in the modeling group and 65 in the validation group. Through Lasso regression variable screening and Logistic regression analysis, the results showed that ALBI score(OR=8.062, 95% CI: 2.545-25.540), alanine transaminase (ALT) (OR=1.037, 95% CI: 1.004-1.071) and CEA (OR=1.025, 95% CI: 1.008-1.043) were independent predictors of liver metastasis in colorectal cancer. The area under curve (AUC) of the combined prediction of liver metastasis of colorectal cancer in the modeling group was 0.921, the sensitivity was 78%, the specificity was 95%, the C-index was 0.921, the H-L fitting curve χ²=0.851, P=0.654, and the slope of the calibration curve was close to 1, suggesting that the accuracy of the model was high, and the DCA curve showed that the model had good clinical application value. For the data of the modeling group, the Bootstrap method was used for internal verification of 1000 resamplings. The accuracy was 0.869, the kappa consistency was 0.709, and the AUC was 0.913. When ALBI score, ALT and CEA were used to diagnose liver metastasis of colorectal cancer alone, the AUC of CEA was the largest (0.897), and the combination of the three had the highest efficacy in the diagnosis of liver metastasis of colorectal cancer. In the validation group, the AUC, sensitivity, specificity, C-index of the combined prediction of liver metastasis of colorectal cancer were 0.918, 85.0%, 95.6%, 0.918, respectively, and H-L fitting curve χ²=0.586, P=0.746.  Conclusions  ALBI score, ALT and CEA have certain predictive value for liver metastasis of colorectal cancer. The combined diagnosis of liver metastasis of colorectal cancer has high efficacy, and the risk prediction model constructed has a good predictive effect.

【Objective】 To evaluate the dietary quality with the dietary balance index (DBI_16) and the association between dietary quality and bone mass among middle-aged and elderly people in Gansu Province so as to provide evidence for improving dietary quality and bone health status of Gansu population. 【Methods】 Based on the information of the type and quantity of food intake and the bone mass of middle-aged and elderly people aged 35 years and above collected by the Gansu Project in the Regional Ethnic Cohort Study in Northwest China, DBI_16 was used to evaluate the intake level of cereals, vegetables, fruits, milk, beans, fish and shrimp, eggs and other foods, and the degree of inadequate, excessive and unbalanced dietary intake of the participants. Multiple linear regression was used to evaluate the associations of three component indexes of DBI_16, high bound score (DBI_HBS), low bound score (DBI_LBS), diet quality distance (DBI_DQD), and seven single indexes of DBI_16 with bone mass. 【Results】 Analyses of the dietary and bone mass data of 11,840 participants showed that 44.8% of participants consumed excessive amounts of cereals compared to the dietary recommendation. 96.3%, 90.6%, 90.1%, 71.9%, 95.1% and 60.3% of participants’ intake of vegetables, fruits, milk, soybeans, fish and shrimp, and eggs, respectively, were inadequate. 47.7% participants consumed less than 10 types of food. 2.3% participants’ DBI_LBS levels were appropriate. 54.7% participants’ DBI_HBS levels were appropriate. Only 1.2% participants’ DBI_DQD reached a balanced level. The bone mass level in the study population was (2.5±0.6) kg [(2.8±0.5) kg for men and (2.3±0.5) kg for women]. After adjusting for sociodemographic characteristics, lifestyle, total dietary energy intake and body mass index, DBI_LBS and DBI_DQD were negatively associated with bone mass [β and 95% CI was -0.002 01 (-0.003 62--0.000 40) and -0.001 76 (-0.003 09--0.000 43), respectively]. 【Conclusion】 Dietary intake imbalance is common among middle-aged and elderly people in Gansu Province, and the more severe the dietary intake imbalance, the lower the bone mass level.

Seed quality plays an important role in the agricultural and animal husbandry production, the effective utilization of genetic resources, the conservation of biodiversity and the restoration and reconstruction of plant communities. Seed aging is a common physiological phenomenon during storage. It is a natural irreversible process that occurs and develops along with the extension of seed storage time. It is not only related to the growth, yield and quality of seed and seedling establishment, but also has an important effect on the conservation, utilization and development of plant germplasm resources. The physiological mechanisms of seed aging are complex and diverse. Most studies focus on conventional physiological characterization, while systematic and comprehensive in-depth studies are lacking. Here we review the recent advances in understanding the physiology of seed aging process, including the methods of seed aging, the effect of aging on seed germination, and the physiological and molecular mechanisms of seed aging. The change of multiple physiological parameters, including seed vigor, electrical conductivity, malondialdehyde content and storage material in the seed, antioxidant enzyme activity and mitochondrial structure, were summarized. Moreover, insights into the mechanism of seed aging from the aspects of transcriptome, proteome and aging related gene function were summarized. This study may facilitate the research of seed biology and the conservation and utilization of germplasm resources.
Germination ; Plants ; Proteome ; Seedlings ; Seeds/genetics*

Phenylalaninammo-nialyase (PAL) is a key enzyme in the synthesis of methyl benzoate - a plant aroma compound. In order to understand the function of this enzyme in the formation of fragrance in the scented Rhododendron species-Rhododendron fortunei, we cloned a gene encoding this enzyme and subsequently examined the gene expression patterns and the profile of enzyme activity during development in various tissues. The full length of RhPAL gene was cloned by reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends (RACE) techniques. The expression levels of RhPAL gene were measured by real-time quantitative reverse transcription PCR (qRT-PCR) and the amount of phenylalanine and cinnamic acid were assayed with LC-MS. The results showed that the ORF sequence of RhPAL gene amplified from the cDNA templates of flower buds had 2 145 bp, encoding 715 amino acids, and shared 90% homology to the PAL amino acid sequences from other species. qRT-PCR analysis showed that the expression of RhPAL in petals during flowering kept in rising even until the flowers wilted. The expression of RhPAL in pistil was much higher than that in stamen, while the expression in the younger leaves was higher than in old leaves. However, the expression level was relatively lower in petal and stamen compared to that in leaves. We also measured the PAL activity by Enzyme-linked immuno sorbent assay in the petals of flowers at different flowering stages. The results showed that PAL activity reached the highest at the bud stage and then decreased gradually to the lowest when the flowers wilted, which followed a similar trend in the emission of the flower fragrance. The phenylalanine and cinnamic acid contents measured by LC-MS were highly correlated to the expression level of RhPAL in various tissues and at different flowering stages, implying that RhPAL plays an important role in the formation of the flower fragrance. This work may facilitate the breeding and improvement of new fragrant Rhododendron cultivars.
Amino Acid Sequence ; Cloning, Molecular ; DNA, Complementary ; Flowers/genetics* ; Rhododendron/genetics*

Terpene synthase (TPS) plays important roles in the synthesis of terpenoids which are the main fragrances in Rhododendron flowers. To understand the function of TPS genes in terpenoid metabolism in relation to flower aroma formation, we identified all TPS gene family members in Rhododendron by analyzing its genome database. We then used a transcriptomic approach to analyze the differential gene expression patterns of TPS gene family members in the scented flower Rhododendron fortunei compared to the non-scented flower Rhododendron 'Nova Zembla'. The contents of terpenoid compounds in petals of the above two Rhododendron species at different developmental stages were also measured by using qRT-PCR and head space-solid phase micro-extraction combined with gas chromatography-mass spectrometry. Our results showed that a total of 47 RsTPS members, with individual lengths ranged from 591 to 2 634 bp, were identified in the Rhododendron genome. The number of exons in RsTPS gene ranged from 3 to 12, while the length of each protein encoded ranged from 196 to 877 amino acids. Members of the RsTPS family are mainly distributed in the chloroplast and cytoplasm. Phylogenetic analysis showed that RsTPS genes can be clustered into 5 subgroups. Seven gene family members can be functionally annotated as TPS gene family since they were temporally and spatially expressed as shown in the transcriptome data. Notably, TPS1, TPS10, TPS12 and TPS13 in Rhododendron fortunei were expressed highly in flower buds reached the peak in the full blossoming. Correlation analysis between gene expression levels and terpenoid content indicates that the expression levels of TPS1, TPS4, TPS9, TPS10, TPS12 and TPS13 were positively correlated with the content of terpenoids in the petals of R. fortunei at all flower developmental stages, suggesting that these six genes might be involved in the aroma formation in R. fortunei.
Rhododendron/metabolism* ; Phylogeny ; Terpenes/metabolism* ; Family ; Gene Expression Regulation, Plant

Objective To explore the predictive value of the expression of CD44v6 and EGFR on the efficacy of neoadjuvant chemotherapy (NACT) in stageⅡ-Ⅲ cervical cancer. Methods A total of 53 patients with stageⅡ-Ⅲ cervical cancer diagnosed by pathology were selected. All patients received two cycles of paclitaxel+platinum NACT. The pathological tissue samples of cervical tumors before NACT treatment were collected. The expression of CD44v6 and EGFR were detected by the immunohistochemical SP method, and we analyzed their predictive value of NACT in stageⅡ-Ⅲ cervical cancer. Results Among the 53 patients, 38 were in the NACT effective group (CR+PR), and 15 were in the NACT ineffective group (SD+PD). The expression of CD44v6 in the ineffective group was significantly higher than that in the effective group (P < 0.05). The expression of CD44v6 was significantly different in patients with CR, PR, and SD (P < 0.05). The AUC of CD44v6 to NACT effect on stage Ⅱ-Ⅲ cervical cancer was 0.74 (P < 0.05). The patients in the high expression group of CD44v6 had worse efficacy in NACT than those in the low expression group of CD44v6 (P < 0.05). Pearson test showed that CD44v6 and EGFR expression were correlated (R=0.34, P < 0.05). Conclusion High expression of CD44v6 may reduce the efficacy of NACT in stageⅡ-Ⅲ cervical cancer, suggesting that the expression of CD44v6 has a certain predictive value and clinical significance in the efficacy of paclitaxel+platinum NACT on cervical cancer. Moreover, CD44v6 is positively correlated with EGFR expression.

Objective:To explore the clinical strategies for preservation of the exposed implant in chronic wounds and wound repair.Methods:From January 2016 to January 2019, totally 8 patients (4 males and 4 females, aged 10 to 73 years) sustaining postoperative chronic wounds with exposed implants were admitted to the Fourth Medical Center of PLA General Hospital. There were 2 cases of abdominal patch exposure after abdominal trauma surgery, 2 cases of titanium plate exposure post craniocerebral surgery, 3 cases of internal fixator exposure post orthopedic surgery, and 1 case of cerebrospinal fluid drainage tube exposure after craniocerebral surgery. The wound exudate was collected for bacterial culture on admission. On the basis of glycemic control and correction of anemia and hypoproteinemia, thorough wound debridement was performed as soon as possible and the wound area after debridement ranged from 2.0 cm×0.5 cm to 6.0 cm×5.0 cm. The wounds of 4 patients were immediately closed after debridement, including 1 case by primary closure, 1 case by primary closure after local filling of platelet rich plasma gel, and 2 cases by local flap transplantation, with flap size of 10.0 cm×8.0 cm and 12.0 cm×8.0 cm, respectively. The donor sites of flaps were sutured directly and all the incisions were treated with continuous vacuum sealing drainage (VSD) after surgery. The other 4 patients were treated with continuous VSD after debridement to improve the wound bed. The wound of 1 case healed gradually, 1 case received direct wound suturing, and the wounds of 2 cases were repaired with thin split-thickness skin grafts from the thigh or the head. The results of bacterial culture of wound exudate on admission, wound healing post surgery, and follow-up were observed and recorded.Results:The bacterial culture of wound exudate on admission was positive in 6 patients, and 10 strains of bacteria were isolated with Staphylococcus epidermidis as the main pathogen. All the skin grafts or flaps of patients survived post surgery, with the incisions and wounds healed and all the implants preserved. After 1 to 3 years of follow-up, no recurrence of wound was found in any patient. Conclusions:The postoperative chronic wounds with exposed implants can be closed in primary stage by direct suturing or flap transplantation if it is clean enough on the basis of thorough debridement. The wounds with large defects or serious infection can be treated with continuous VSD firstly and then closed with direct suturing or skin grafting for delayed wound closure, thereby to reach the treatment goal of preserving the implants and repairing the wounds simultaneously.

Objective: To investigate the effects of platelet-rich plasma (PRP) combined with polylactic acid/polycaprolactone (PLA/PCL) on healing of mininature pig deep soft tissue defect caused by fragment injury. Methods: Two male Bama miniature pigs with 11 to 12 months (the same below) were selected by lottery to prepare PRP. The other twenty-seven male Bama miniature pigs were used to reproduce deep soft tissue defect caused by high-explosive ammunition fragment injury on bilateral posterior femoral region. According to the random number table, 27 pigs were divided into control group, material group, and PRP+material group, with 9 pigs in each group. After debridement, wounds of pigs in material group and PRP+material group were filled with PLA/PCL and PLA/PCL+2 mL activated PRP, respectively. Pigs in each group received suture of full-thickness skin to close the wounds. The operative duration was recorded. The length and volume of wounds of pigs in the above groups were measured immediately after surgery. In 1, 2, and 4 weeks after surgery, 3 pigs in each group were sacrificed to collect femoral wounds tissue on two sides, and PLA/PCL were collected from wounds of pigs in material group and PRP+material group for general observation of wounds tissue and degradation of the material. In 2 and 4 weeks after surgery, wounds tissue was obtained to observe the histological changes by hematoxylin-eosin staining, and expressions of transforming growth factor β (TGF-β) and vascular endothelial growth factor (VEGF), and angiogenesis were determined by immunohistochemical method. In 1, 2, and 4 weeks after surgery, wounds tissue was collected to determine mRNA expressions of TGF-β and VEGF by real-time quantitative reverse transcription polymerase chain reaction. Data were processed with analysis of variance of factorial design, one-way analysis of variance, and least significant difference-t test. Results: (1) There were no significantly statistical differences in length and volume of the wounds of pigs among the three groups (F=0.336, 0.282, P>0.05). The operative duration in control group [(30.9±2.1)min] was significantly shorter than that of material group [(39.7±2.2)min] and PRP+material group[(40.0±2.6)min], t=-11.45, -11.88, P<0.01. (2) There were respectively 10, 7, and 5 wounds tissue with infection in pigs of control group, material group, and PRP+material group. In 1, 2, 4 weeks after surgery, all of the wounds tissue of pigs was infected in control group, while none of wounds tissue of pigs was infected in material group and PRP+material group. In pigs of material group and PRP+material group, materials and tissue were easily separated in 1 week after surgery; some materials were integrated with tissue and showed a tendency of degradation in 2 weeks after surgery; materials were completely embedded with tissue in 4 weeks after surgery. (3) In pigs of control group, erythrocytes and inflammatory cells infiltration in wounds tissue were observed in 2 weeks after surgery, and necrotic tissue and inflammatory cells infiltration in wounds tissue were still observed in 4 weeks after surgery. In pigs of material group and PRP+material group, a large number of erythrocytes and inflammatory cells infiltration were observed in 2 weeks after surgery. Compared with that of material group, wounds tissue of pigs in PRP+material group had no inflammatory cells infiltration in 4 weeks after surgery. (4) Protein expressions of TGF-β in fibroblasts and multinuclear macrophagocytes, VEGF in fibroblasts and vascular endothelial cells, and blood vessel formation in wounds tissue of pigs in PRP+material group were significantly more than those of pigs in control group and material group in 2 and 4 weeks after surgery. (5) The mRNA expression of TGF-β in wounds tissue of pigs in material group was significantly higher than that in control group in 4 weeks after surgery (t=-3.93, P<0.01). Compared with those of pigs in control group and material group, the mRNA expression of TGF-β in wounds tissue of pigs in PRP+material group was significantly increased at each time point (t=9.23, 13.81, 11.73, -7.51, -12.04, -7.80, P<0.01). The mRNA expression of VEGF in wounds tissue of pigs increased significantly in material group compared with that of pigs in control group in 4 weeks after surgery (t=-3.94, P<0.01). Compared with those of pigs in control group and material group, the mRNA expression of VEGF in wounds tissue increased significantly in wound tissue of pigs in PRP+material group at each time point (t=12.33, 3.95, 7.97, -11.36, -2.97, -4.04, P<0.01). Conclusions PRP combined with PLA/PCL can accelerate wound healing of deep soft tissue defect of mininature pigs caused by fragment injury by providing physical scaffold for newborn tissue growth, promoting mRNA and protein expressions of TGF-β and VEGF.

Objective To explore the effect of bronchoalveolar lavage combined with mechanical ventilation on the clinical symptoms and pulmonary function of elderly patients with severe asthma.Methods A total of 70 patients with severe asthma were selected and randomly divided into observation group and control group.The observation group was given routine treatment,bronchoalveolar lavage and mechanical ventilation,while the control group was given routine treatment and mechanical ventilation.Clinical symptoms,airway function,inflammatory mediators and effect were compared between two groups.Results The effective rate of observation group was 94.29%,which was significantly higher than 77.14% of control group (P<0.05).Clinical symptoms,duration of mechanical ventilation and ICU stay of observation group were significantly shorter than the control group (P<0.05).In the observation group,FEV1,FVC and FEV1/FVC% were significantly higher than the control group (P<0.05),and CRP,TNF-α and IL-6 were significantly lower than the control group (P<0.05).Conclusion Bronchoalveolar lavage combined with mechanical ventilation can improve the clinical symptoms and pulmonary function,alleviate the inflammatory reaction and improve the therapeutic effect.