[Incidence of diabetes and influencing factors in HIV-infected individuals after antiretroviral therapy in Dehong Dai and Jingpo Autonomous Prefecture]

Objective: To understand the incidence of diabetes and influencing factors, the trend of FPG change and risk for mortality in HIV-infected individuals after antiretroviral therapy (ART) in Dehong Dai and Jingpo Autonomous Prefecture (Dehong). Methods: The HIV/AIDS treatment database was collected from China Information System for Disease Control and Prevention. This retrospective cohort study was conducted in HIV-infected individuals with access to ART in Dehong during 2004-2020.The Cox proportional hazard regression model was used to analyze the incidence density of diabetes, the influencing factors and risk for mortality in HIV-infected individuals with access to ART, mixed linear effects model was used to analyze the trend of FPG change and predict FPG in those with different glucose metabolic status at baseline survey. Statistical analysis was performed using software SAS 9.4. Results: A total of 8 763 HIV-infected individuals were included, in whom 8 432 (96.2%) had no diabetes, 331 had diabetes. The incidence density of diabetes was 2.31/1 000 person years. Multivariate Cox proportional hazard regression analysis revealed that 30- 59 years old, BMI ≥24.0 kg/m2, Efavirenz (EFV) based initial treatment regimen and impaired fasting glucose (IFG) at baseline survey were significantly and positively associated with incidence of diabetes. Mixed effect model revealed that FPG was positively correlated with the duration of ART, age and baseline FPG. Suffering from diabetes was a risk factor for mortality in HIV-infected individuals both at baseline survey and during follow-up. Conclusions: The risk for diabetes increased in HIV-infected individuals who were 30-59 years old, baseline BMI ≥24.0 kg/m2, received EFV based initial treatment, and IFG in HIV-infected individuals after antiretroviral therapy in Dehong, 2004-2020. It is important to pay close attention to their blood glucose, and patients with high blood glucose should receive treatment as early as possible.

[Proximal tibial aspect ratio and matching of tibial component in total knee arthroplasty: a narrative review]

Proximal tibial aspect ratio (PTAR) is closely related to age, disease status and cutting parameters with considerable inter-individual variation independent of gender and race, nevertheless the aspect ratio of tibial components from different manufacturers remains relatively constant from smallest to largest size. As a result, component mismatching is an unavoidable dilemma during tibia preparation in total knee arthroplasty (TKA). Various prosthesis systems all can achieve more than 80% coverage on proximal tibia, whereas their optimal fit rates are generally not more than 50%. It is difficult for symmetrical components to avoid anteroposterior mismatch, internal malrotation tends to occur when maximum coverage is pursued on the resected surface with a medial dominant plateau or lower PTAR. Although it is easier to achieve a balance of rotation and coverage with anatomical components, significant anteromedial overhang tends to appear on the resected surface with a symmetrical or lateral dominant plateau. Further researches should focus on the law of inter-individual variability of proximal tibial morphology, the quantitative definition of "ideal matching" safety zone of key morphological parameters on different areas of proximal tibia and the methodology of realizing"ideal matching"in the majority patients with the least amount of component sizes. In addition, with the rapid development of additive manufacturing and digital orthopedic technology, individual customized implant is expected to become a breakthrough point in the field of TKA component fitting.

[Rotational alignment of the tibial component in total knee arthroplasty:a narrative review]

Component malrotation is one of the major causes of failure in total knee arthroplasty.Based on previous researches,Insall line has excessive external rotation tendency.Although Akagi line is the most recognized anatomical axis at present,it still has a certain tendency of internal rotation.The tibial posterior condylar axis is not suitable for symmetrical component and yet the Curve-on-Curve technique is not suitable for anatomic component.In addition,reference to any fixed anatomical markers cannot ensure the rotation consistency of tibiofemoral component in extension position.Although range of motion technique is beneficial to tibiofemoral rotation synchronization,its clinical effect seems to be unstable.Nevertheless,Patients can obtain good postoperative results with all major techniques.Before the recognized "gold standard" is defined,orthopedic surgeons can determine the rotation alignment of tibial component according to their most accustomed surgical method.With a deeper understanding of knee anatomy,biomechanics and kinematics,digital assistive technology may be expected to become a breakthrough in the tibial rotational alignment.

[A longitudinal analysis on dynamic change of platelet count in HIV-infected patients with access to antiretroviral therapy in Dehong Dai and Jingpo Autonomous Prefecture]

Objective: To explore the dynamic change of platelet count and related factors in HIV-infected patients with access to antiretroviral therapy (ART) in Dehong Dai and Jingpo autonomous prefecture of Yunnan province. Methods: A longitudinal analysis was used to analyze the dynamic change of platelet count in HIV-infected patients with access to ART. Linear mixed model (LMM) was used to analyze factors associated with the dynamic change of platelet count. Stratified analysis and sensitivity analysis were also conducted. Results: A total of 761 HIV-infected patients were recruited and 608 cases had at least one follow-up record (80.0%,608/761). 374, 555 and 233 cases were investigated in follow-up visits at month 6, 12 and 24, respectively. The mean platelet count and the proportion of higher platelet count (>300×10⁹/L) were significantly higher in women than in men at both baseline survey and each follow-up visit (P<0.05). Among patients with no obvious liver fibrosis, the mean platelet count was significantly higher in women than in men at baseline survey and each follow-up visit; while in the patients with liver fibrosis, the mean baseline platelet count was still significantly higher in women than in men, but the difference had no significance at follow-up visits. Results of LMM revealed that follow-up platelet count was positively correlated with gender (β=5.90, 95%CI: 1.09-10.70, P=0.016), baseline platelet count (β=0.82, 95%CI: 0.79-0.86, P<0.001) and time (β=1.76, 95%CI: 1.52-2.01, P<0.001). Sensitivity analysis among 220 cases who had both 12- and 24-month follow-up visits further confirmed that follow-up platelets count was still positively associated with gender (β=10.50, 95%CI: 2.24-18.74, P=0.013), baseline platelet count (β=0.71, 95%CI: 0.65-0.77, P<0.001) and time (β=1.60, 95%CI: 1.20-1.99, P<0.001) but negatively associated with age (β=-0.42, 95%CI: -0.78--0.06, P=0.021). Conclusions: The platelet count of HIV-infected patients gradually increased after ART. The mean platelet count was consistently higher in women than in men. Attention should be paid to the gender specific difference in platelet count in HIV-infected patients and timely intervention should be given to reduce the morbidity and mortality of platelet-related diseases.

[A retrospective cohort study of incidence of anemia and risk factors in HIV/AIDS patients with access to antiretroviral therapy in Dehong Jingpo and Dai Autonomous Prefecture in Yunnan province, 2004-2018]

Objective: To investigate the incidence of anemia and risk factors in HIV/AIDS patients with access to antiretroviral therapy (ART) during 2004-2018 in Dehong Jingpo and Dai Autonomous Prefecture (Dehong). Methods: A retrospective cohort study was conducted in HIV/AIDS patients receiving ART in Dehong during 2004-2018 based on the data extracted from the National HIV/AIDS antiretroviral therapy database. Cox proportional risk model was used to analyze the factors associated with the incidences of anemia and moderate or severe anemia in the HIV/AIDS patients. And the piecewise linear mixed-effects model was used to depict the trajectory of hemoglobin changes over time after initiating ART according to baseline level. Results: A total of 8 044 HIV/AIDS patients were included, in whom 6 337 (78.8%) were without anemia at baseline survey and had a median follow up time of 4.43 (P₂₅, P₇₅: 1.50, 6.71) years. The median follow up time for 1 291 new anemia cases and 293 new moderate or severe anemia cases was 0.16 (P₂₅, P₇₅: 0.07, 1.99) years and 0.48 (P₂₅, P₇₅:0.09, 2.97) years, respectively. The incidence rate of anemia and moderate or severe anemia was 4.40 per 100 person-years and 0.41 per 100 person-years respectively. In multivariable Cox regression analysis, older age, being female, being in Dai and Jingpo ethnic group, baseline BMI <18.5 kg/m², baseline CD4⁺T lymphocyte cell counts (CD4) <200 cells/μl, and zidovudine (AZT) -based initial treatment regimen were factors significantly and positively associated with incidence of anemia after treatment. Factors as being female, being in Dai ethnic group, baseline BMI <18.5 kg/m², mild baseline anemia, and AZT-based initial treatment regimen were significantly and positively associated with incidence of moderate or severe anemia after treatment. Conclusion: The risk for anemia was higher in HIV/AIDS patients with specific characteristics, such as age ≥60 years , being female, being in Dai and Jingpo ethnic groups, lower BMI, CD4 <200 cells/μl, and treatment of AZT, after initiation of ART in Dehong during 2004-2018. Additional efforts are needed to strengthen the screening, prevention and treatment of anemia in this population.

[Prevalence and related factors of CD4+T lymphocytes immune recovery among adult HIV/AIDS on antiretroviral therapy in Dehong Dai and Jingpo Autonomous Prefecture]

Objective: To analyze the longitudinal characteristics of CD4⁺T lymphocytes (CD4) among the adult HIV/AIDS on antiretroviral therapy (ART) and the related factors. Methods: A retrospective cohort of adult HIV/AIDS starting ART in Dehong Dai and Jingpo Autonomous Prefecture (Dehong) in 2007-2016 was followed up to December 31, 2018. Group-based trajectory models were utilized to identify CD4 subgroups based on immune recovery (whether and when CD4 reached the average level of >500 cells/μl). The demographics and information at ART baseline were described, and the related factors were analyzed with polytomous logistic regression. The SAS 9.4 software was used for statistical analysis. Results: A total of 7 605 adults with HIV/AIDS were included, of which the median (P₂₅,P₇₅) age at ART were 36 (30,43) years old, 61.0% were male, 42.5% were Han nationality, and 60.8% with the education of primary school or below. The follow-up duration M (P₂₅, P₇₅) was 6.1 (4.1,8.1) years. HIV/AIDS in Dehong showed four CD4 trajectory subgroups from low to high: below the average level, primary recovery to a normal level, full recovery to a moderate level, and normal steady level, accounting for 34.4%, 39.8%, 20.6%, and 5.2%, respectively. When compared with corresponding control groups, age <35 years at ART, female, education of middle school or above, sexual transmission, no opportunistic infection, CD4 ≥200 cells/μl, baseline regimen with tenofovir (TDF) and time from HIV diagnosis to ART <1 year were the related factors facilitating the higher CD4 subgroups. Conclusions: The various CD4 immune recoveries of HIV/AIDS were changing patterns after ART. Starting ART with a high CD4 level was beneficial to CD4 recovery to normal level during the follow-up period. Early initiation of ART and exceptional attention to CD4 immune recovery should be encouraged after the ART.

[Incidence and influencing factors of AIDS-related and non-AIDS-related deaths after receiving antiretroviral therapy among HIV-positive individuals in Dehong Dai and Jingpo Autonomous Prefecture, 2010-2019]

Objective: To explore the changing trends and influencing factors of AIDS-related and non-AIDS-related deaths after receiving antiretroviral therapy (ART) among HIV-positive individuals in Dehong Dai Jingpo autonomous prefecture (Dehong) from 2010 to 2019. Methods: Based on the Chinese National treatment database, HIV patients who initiated ART from 2010 to 2019 were included in the analysis. The cumulative incidence function was used to estimate the cumulative incidence of AIDS-related death and non-AIDS-related death, respectively. The Fine-Grey model was used to compare the differences between AIDS-related and non-AIDS-related deaths and analyze its influencing factors. Results: A total of 7 068 HIV-positive individuals were included, of which 388 were AIDS-related deaths and 570 were non-AIDS-related deaths. The cumulative mortality rate at years 1, 2, 3, 4, 5, 7 and 9 after receiving ART were 2.27%, 3.46%, 4.47%, 5.03%, 5.84%, 6.61%, 7.40% for AIDS-related deaths, and 1.63%, 3.11%, 4.68%, 6.02%, 7.42%, 10.49%, 12.75% for non-AIDS-related deaths, respectively. In the Fine-Grey model, older age at ART initiation, male, unmarried, injection drug use as the transmission route, lower baseline BMI, lower baseline CD4⁺ T cell counts, baseline FIB-4 score >3.25, and baseline anemia were risk factors for AIDS-related death. In contrast, age at ART initiation ≥45 years, male, Dai, and Jingpo minority ethnicities, unmarried, injection drug use as the transmission route, lower baseline BMI, baseline FIB-4 score >3.25, baseline eGFR <60 ml·min^-1·1.73 m^-2, and baseline anemia were risk factors for non-AIDS-related deaths. Conclusions: The cumulative mortality rate was low among HIV-positive individuals after receiving ART in Dehong during 2010-2019. The mortality of non-AIDS-related deaths was higher than that of AIDS-related deaths. There were also differences in the factors influencing AIDS-related and non-AIDS-related deaths and interventions should be intensified to target the influencing factors for non-AIDS-related deaths.

Drying temperature regulates vigor of high moisture rice seeds via involvement in phytohormone, ROS, and relevant gene expression

BACKGROUND

Rice is an important food crop in China. Seed drying is an important step in the production of rice seeds. However, the regulatory mechanism of the effect of drying temperature on vigor of rice seeds with high initial moisture content (IMC) has not been examined.

RESULTS

This study presents hot-air drying of rice seeds with high IMC (>30%) to assess the effect of drying temperature (35, 41, and 47 °C) on drying performance and seed vigor in terms of germination capacity. The results show a significant positive correlation between the drying rate, seed temperature, and drying temperature. High-temperature drying tends to cause a large accumulation of reactive oxygen species (ROS) and increases the activity of antioxidant enzymes in rice seeds. High-temperature drying also significantly increased abscisic acid (ABA) content and decreased gibberellin (GA) content through the regulation of the activity of metabolism related-enzymes. Moreover, changes in GA and ABA metabolism during early seed germination might be an important reason for the decrease in seed vigor with high-temperature drying. High-temperature drying also significantly inhibited the activity of α-amylase during early seed germination.

CONCLUSION

A drying temperature of 35 °C was safe for rice seeds with high IMC, whereas higher drying temperatures (41 and 47 °C) reduced rice seed vigor remarkably. The metabolism of ROS, antioxidant enzymes, GA, ABA, and α-amylase might be closely involved in the regulation of the effect of drying temperature on the seed vigor of rice seeds with high IMC. The results of this study, therefore, provide a theoretical basis and technical guidance for mechanical drying of rice seeds. © 2020 Society of Chemical Industry.

[Application of clip remodeling technique in microsurgical treatment of intracranial aneurysms via keyhole approaches]

Objective: To discuss the value and technique of clip remodeling in microsurgical treatment of intracranial aneurysms via keyhole approaches. Methods: The clinical data of patients with intracranial aneurysms, who were treated by microsurgical clipping via keyhole approaches from January 2017 to December 2019, were retrospectively analyzed. The clips were remodeled based on the aneurysmal characteristics during the procedure in 27 cases. Angiography was obtained within one week after surgery in order to evaluate the position of clips and the security of lesions. All patients were followed up at the outpatient clinic to assess the clinical outcomes. Results: A total of 27 patients harbored 30 intracranial aneurysms, including 23 ruptured lesions and 7 unruptured ones. There were 9 middle cerebral artery aneurysms, 11 anterior communicating artery aneurysms, 9 posterior communicating artery aneurysms and 1 anterior cerebral artery aneurysm, respectively. Nine patients were operated via supraorbital keyhole approach, as well as 17 via pterional keyhole approach and one via hemispheric keyhole approach. Postoperative angiography revealed complete obliteration of lesions without residual filling in all cases. Twenty-five patients recovered well at discharge and two presented with mild disability. After 3-36 months of follow-up, no rebleeding and new-onset neurological deficits were noted. Conclusion: Clip remodeling technique is a simple and effective option, which can alleviate the limitation of manipulative freedom under keyhole approaches and improve the microsurgical effect of intracranial aneurysms.

Drying temperature affects rice seed vigor via gibberellin, abscisic acid, and antioxidant enzyme metabolism

Seed vigor is a key factor affecting seed quality. The mechanical drying process exerts a significant influence on rice seed vigor. The initial moisture content (IMC) and drying temperature are considered the main factors affecting rice seed vigor through mechanical drying. This study aimed to determine the optimum drying temperature for rice seeds according to the IMC, and elucidate the mechanisms mediating the effects of drying temperature and IMC on seed vigor. Rice seeds with three different IMCs (20%, 25%, and 30%) were dried to the target moisture content (14%) at four different drying temperatures. The results showed that the drying temperature and IMC had significant effects on the drying performance and vigor of the rice seeds. The upper limits of drying temperature for rice seeds with 20%, 25%, and 30% IMCs were 45, 42, and 38 °C, respectively. The drying rate and seed temperature increased significantly with increasing drying temperature. The drying temperature, drying rate, and seed temperature showed extremely significant negative correlations with germination energy (GE), germination rate, germination index (GI), and vigor index (VI). A high IMC and drying temperature probably induced a massive accumulation of hydrogen peroxide (H₂O₂) and superoxide anions in the seeds, enhanced superoxide dismutase (SOD) and catalase (CAT) activity, and increased the abscisic acid (ABA) content. In the early stage of seed germination, the IMC and drying temperature regulated seed germination through the metabolism of H₂O₂, gibberellin acid (GA), ABA, and α-amylase. These results indicate that the metabolism of reactive oxygen species (ROS), antioxidant enzymes, GA, ABA, and α-amylase might be involved in the mediation of the effects of drying temperature on seed vigor. The results of this study provide a theoretical basis and technical guidance for the mechanical drying of rice seeds.

Structural insights into the catalysis and substrate specificity of cyanobacterial aspartate racemase McyF

L-amino acids represent the most common amino acid form, most notably as protein residues, whereas D-amino acids, despite their rare occurrence, play significant roles in many biological processes. Amino acid racemases are enzymes that catalyze the interconversion of L- and/or D-amino acids. McyF is a pyridoxal 5'-phosphate (PLP) independent amino acid racemase that produces the substrate D-aspartate for the biosynthesis of microcystin in the cyanobacterium Microcystis aeruginosa PCC7806. Here we report the crystal structures of McyF in complex with citrate, L-Asp and D-Asp at 2.35, 2.63 and 2.80 Å, respectively. Structural analyses indicate that McyF and homologs possess highly conserved residues involved in substrate binding and catalysis. In addition, residues Cys87 and Cys195 were clearly assigned to the key catalytic residues of "two bases" that deprotonate D-Asp and L-Asp in a reaction independent of PLP. Further site-directed mutagenesis combined with enzymatic assays revealed that Glu197 also participates in the catalytic reaction. In addition, activity assays proved that McyF could also catalyze the interconversion of L-MeAsp between D-MeAsp, the precursor of another microcystin isoform. These findings provide structural insights into the catalytic mechanism of aspartate racemase and microcystin biosynthesis.

[Screening different HPV genotypes infection and type-specific in cervical exfoliated cells of women in Yili area of Xinjiang Uygur Autonomous Region, China]

Objective: To investigate the infection status and genotype distribution of cervical human papillomavirus (HPV) in women of different ethnic groups and different ages in Yili, Xinjiang Uygur Autonomous Region (Xinjiang). Methods: By using the convenient sampling method, 54 760 women from November 2015 to May 2017 seeking for service in gynecological clinics in a general hospital in Yili, Xinjiang, were selected as the research subjects, and 3 445 samples of cervical mucous exfoliative cells were collected, and the social information of their ethnic and age was collected at the same time. The inclusion criteria were those with sexual life, cervical integrity, and ethnic groups for Han or Uygur or Kazak. PCR-reverse dot blot hybridization was used to detect HPV genotyping in exfoliated cells, and chi-square test was used to compare the difference of HPV positive rate among different ethnic groups. Then, according to ethnicity and age, the differences in positive rates of different ages and ethnic groups were compared in each layer. Results: The positive rate of HPV was 25.6% (882 cases), of which the Han, Uygur and Kazakh were 27.9% (564 cases), 22.9% (196 cases) and 21.6% (122 cases), and the difference was statistically significant (χ(2)=13.80, P=0.001). The most prevalent high-risk genotypes of Han women were HPV16/52/58, accounting for 24.8% (140 cases), 17.7% (100 cases) and 9.8% (55 cases), respectively. The most prevalent high-risk genotypes of Uygur women were HPV16/52/53, accounting for 34.2% (67 cases), 12.8% (25 cases), 9.2% (18 cases), respectively. The most prevalent high-risk genotypes of Kazak were HPV16/52/53, accounting for 37.7% (46 cases), 17.2% (21 cases), 12.3% (15 cases), respectively. The highest rate of HPV in Uygur patients aged ≥61 years was 41.5% (22 cases), and the lowest in group 36-40 years old, 15.9% (21 cases), the difference between different age groups was statistically significant (χ(2)=35.01, P<0.001). Conclusion: The positive rate of HPV infection among Han, Uygur and Kazak in Yili Prefecture of Xinjiang was different, and the HPV positive genotype differs among different ethnic groups.

The pore-forming protein Aep1 is an innate immune molecule that prevents zebrafish from bacterial infection

Following the Aeromonas hydrophila aerolysin, various aerolysin-like pore-forming proteins have been identified from bacteria to vertebrates. We have recently reported the mechanism of receptor recognition and in vitro pore-formation of a zebrafish aerolysin-like protein Dln1/Aep1. However, the physiological function of Aep1 remains unknown. Here we detected that aep1 gene is constitutively expressed in various immune-related tissues of adult zebrafish; and moreover, its expression is significantly up-regulated upon bacterial challenge, indicating its involvement in antimicrobial infection. Pre-injection of recombinant Aep1 into the infected zebrafish greatly accelerated the clearance of bacteria, resulting in significantly increased survival rate. Meanwhile, the induced expression of cytokines such as interleukin IL-1β and tumor necrosis factor TNF-α in zebrafish upon injection of recombinant Aep1 suggested that Aep1 may be a pro-inflammatory protein that triggers the antimicrobial immune responses. However, compared to the overproduction of these cytokines in the infected zebrafish, pre-injection of Aep1 could significantly reduce the expression level of these cytokines, accompanying with a reduced bacterial load. Moreover, the expression profiles through the developmental stages of zebrafish demonstrated that aep1 is activated at the very early stage prior to the maturation of adaptive immune system. Altogether, our findings proved that Aep1 is an innate immune molecule that prevents the bacterial infection.

Studies on optimum harvest time for hybrid rice seed

BACKGROUND

Timely harvest is critical for hybrid rice to achieve maximum seed viability, vigor and yield. However, how to predict the optimum harvest time has been rarely reported so far.

RESULTS

The seed vigor of Zhuliangyou 06 (ZLY06) increased and reached the highest level at 20 days after pollination (DAP), when seed moisture content had a lower value, which was maintained until final seed maturation. For Chunyou 84 (CY84), seed vigor, fresh and dry weight had relatively high values at 25 DAP, when seed moisture content reached the lowest value and changed slightly from 25 to 55 DAP. In both hybrid rice varieties, seed glume chlorophyll content declined rapidly from 10 to 30 DAP and remained at a very low level after 35 DAP. Starch content exhibited an increasing trend during seed maturation, while both soluble sugar content and amylase activity decreased significantly at the early stages of seed development. Moreover, correlation analyses showed that seed dry weight, starch content and superoxide dismutase activity were significantly positively correlated with seed vigor. In contrast, chlorophyll content, moisture content, soluble sugar, soluble protein, abscisic acid, gibberellin content, electrical conductivity, catalase and ascorbate peroxidase activities were significantly negatively correlated with seed vigor. Physiological and biochemical parameters were obviously more closely related with seed vigor than with seed germinability during seed development.

CONCLUSION

Seed vigor could be better used as a comprehensive factor to predict the optimum seed harvest time. It is suggested that for ZLY06 seeds could be harvested as early as 20 DAP, whereas for CY84 the earliest optimum harvest time was 25 DAP. © 2016 Society of Chemical Industry.

Karyotype analysis and ribosomal gene localization of spotted knifejaw Oplegnathus punctatus

The spotted knifejaw, Oplegnathus punctatus, is an important aquaculture fish species in China. To better understand the chromosomal microstructure and the karyotypic origin of this species, cytogenetic analysis was performed using Giemsa staining to identify metaphase chromosomes, C-banding to detect C-positive heterochromatin, silver staining to identify the nucleolus organizer regions (Ag-NORs), and fluorescence in situ hybridization (FISH) for physical mapping of the major (18S rDNA) and minor (5S rDNA) ribosomal genes. The species showed a karyotype of 2n = 48 for females, composed of 2 submetacentric and 46 telocentric chromosomes, with a fundamental number (FN) = 50, while the karyotype of males was 2n = 47, composed of 1 exclusive large metacentric, 2 submetacentric, and 44 telocentric chromosomes, with FN = 50. These karyotype results suggest that O. punctatus might have an X₁X₁X₂X₂/X₁X₂Y multiple sex chromosome system. C-positive heterochromatin was distributed in the centromeres of all chromosomal pairs and in the terminal portions of some chromosomes. A single pair of Ag-positive NORs was found to be localized at the terminal regions of the short arms of the subtelocentric chromosome pair, which was supported by FISH of 18S rDNA. After FISH, 5S rDNA were located on the interstitial regions of the smallest telocentric chromosome pair. This study was the first to identify the karyotype of this species and will facilitate further research on karyotype evolution in the order Perciformes.

Structural Analysis of the Catalytic Mechanism and Substrate Specificity of Anabaena Alkaline Invertase InvA Reveals a Novel Glucosidase

Invertases catalyze the hydrolysis of sucrose to glucose and fructose, thereby playing a key role in primary metabolism and plant development. According to the optimum pH, invertases are classified into acid invertases (Ac-Invs) and alkaline/neutral invertases (A/N-Invs), which share no sequence homology. Compared with Ac-Invs that have been extensively studied, the structure and catalytic mechanism of A/N-Invs remain unknown. Here we report the crystal structures of Anabaena alkaline invertase InvA, which was proposed to be the ancestor of modern plant A/N-Invs. These structures are the first in the GH100 family. InvA exists as a hexamer in both crystal and solution. Each subunit consists of an (α/α)₆ barrel core structure in addition to an insertion of three helices. A couple of structures in complex with the substrate or products enabled us to assign the subsites -1 and +1 specifically binding glucose and fructose, respectively. Structural comparison combined with enzymatic assays indicated that Asp-188 and Glu-414 are putative catalytic residues. Further analysis of the substrate binding pocket demonstrated that InvA possesses a stringent substrate specificity toward the α1,2-glycosidic bond of sucrose. Together, we suggest that InvA and homologs represent a novel family of glucosidases.

Effects of Inulin Supplementation in Low- or High-Fat Diets on Reproductive Performance of Sows and Antioxidant Defence Capacity in Sows and Offspring

This experiment was conducted to investigate the effects of inulin supplementation in low- or high-fat diets on both the reproductive performance of sow and the antioxidant defence capacity in sows and offspring. Sixty Landrace × Yorkshire sows were randomly allocated to four treatments with low-fat diet (L), low-fat diet containing 1.5% inulin (LI), high-fat diet (H) and high-fat diet containing 1.5% inulin (HI). Inulin-rich diets lowered the within-litter birth weight coefficient of variation (CV, p = 0.05) of piglets, increased the proportion of piglets weighing 1.0-1.5 kg at farrowing (p < 0.01), reduced the loss of body weight (BW) and backfat thickness (BF) during lactation (p < 0.05) and decreased the duration of farrowing as well as improved sow constipation (p < 0.05). Sows fed fat-rich diets gained more BW during gestation (p < 0.01), farrowed a greater number of total (+1.65 pigs, p < 0.05) and alive (+1.52 pigs p < 0.05) piglets and had a heavier (+2.06 kg, p < 0.05) litter weight at birth as well as a decreased weaning-to-oestrous interval (WEI, p < 0.01) compared with sows fed low-fat diets. However, it is worth noting that the H diet significantly decreased the serum activities of superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) and increased the serum malondialdehyde (MDA) levels in sows and piglets (p < 0.05). In contrast, HI diet enhanced the activities of T-SOD and GSH-Px and decreased the serum MDA concentrations (p < 0.05) in sows and piglets. In summary, the fat-rich diets fed to sows during gestation had beneficial effects on reproductive performance, but aggravated the oxidative stress in sow and piglets. Inulin-rich diets fed to sow during gestation had beneficial effects on within-litter uniformity of piglet birthweight and enhanced the antioxidant defence capacity of sows and piglets.

Physiological changes and sHSPs genes relative transcription in relation to the acquisition of seed germination during maturation of hybrid rice seed

BACKGROUND

During the production of early hybrid rice seed, the seeds dehydrated slowly and retained high moisture levels when rainy weather lasted for a couple of days, and the rice seeds easily occurred pre-harvest sprouting (PHS) along with high temperature. Therefore it is necessary to harvest the seeds before the PHS occurred.

RESULTS

The seeds of hybrid rice (Oryza sativa L. subsp. indica) cv. Qianyou No1 that harvests from 19 to 28 days after pollination (DAP) all had high seed vigour. The seed moisture content at 10 DAP was 36.1%, and declined to 28.6% at 19 DAP; the contents of soluble sugar and total starch increased significantly with the development of seeds. The soluble protein content, the level of abscisic acid (ABA) and gibberellin (GA3 ), and ascorbate peroxidase (APX) activity continued to decrease from 10 DAP to 19 DAP. The seeds at 19 DAP had the highest peroxidase (POD) activity and lowest catalase (CAT) activity while the superoxide dismutase (SOD) activity had no significant difference among the different developing periods. The relative expressions of genes 64S Hsp18.0 and Os03g0267200 transcripts increased significantly from 10 to 19 DAP, and then decreased. However, no significant change was recorded in soluble protein, sugar and GA3 after 16 DAP, and they all significantly correlated with seed viability and vigour during the process of seed maturity.

CONCLUSION

The seeds of hybrid rice Qianyou No1 had a higher viability and vigour when harvested from 19 DAP to 28 DAP, the transcription levels of 64S Hsp18.0 and Os03g0267200 increased significantly from 10 DAP to 19 DAP and the highest value was recorded at 19 DAP. The seeds could be harvested as early as 19 DAP without negative influence on seed vigour and viability.

Structure of a variable lymphocyte receptor-like protein from the amphioxus Branchiostoma floridae

Discovery of variable lymphocyte receptors (VLRs) in agnathans (jawless fish) has brought the origin of adaptive immunity system (AIS) forward to 500 million years ago accompanying with the emergence of vertebrates. Previous findings indicated that amphioxus, a representative model organism of chordate, also possesses some homologs of the basic components of TCR/BCR-based AIS, but it remains unknown if there exist any components of VLR-based AIS in amphioxus. Bioinformatics analyses revealed the amphioxus Branchiostoma floridae encodes a group of putative VLR-like proteins. Here we reported the 1.79 Å crystal structure of Bf66946, which forms a crescent-shaped structure of five leucine-rich repeats (LRRs). Structural comparisons indicated that Bf66946 resembles the lamprey VLRC. Further electrostatic potential analyses showed a negatively-charged patch at the concave of LRR solenoid structure that might be responsible for antigen recognition. Site-directed mutagenesis combined with bacterial binding assays revealed that Bf66946 binds to the surface of Gram-positive bacteria Staphylococcus aureus and Streptococcus pneumonia via a couple of acidic residues at the concave. In addition, the closest homolog of Bf66946 is highly expressed in the potential immune organ gill of Branchiostoma belcheri. Altogether, our findings provide the first structural evidence for the emergence of VLR-like molecules in the basal chordates.

Activity Augmentation of Amphioxus Peptidoglycan Recognition Protein BbtPGRP3 via Fusion with a Chitin Binding Domain

Peptidoglycan recognition proteins (PGRPs), which have been identified in most animals, are pattern recognition molecules that involve antimicrobial defense. Resulting from extraordinary expansion of innate immune genes, the amphioxus encodes many PGRPs of diverse functions. For instance, three isoforms of PGRP encoded by Branchiostoma belcheri tsingtauense, termed BbtPGRP1~3, are fused with a chitin binding domain (CBD) at the N-terminus. Here we report the 2.7 Å crystal structure of BbtPGRP3, revealing an overall structure of an N-terminal hevein-like CBD followed by a catalytic PGRP domain. Activity assays combined with site-directed mutagenesis indicated that the individual PGRP domain exhibits amidase activity towards both DAP-type and Lys-type peptidoglycans (PGNs), the former of which is favored. The N-terminal CBD not only has the chitin-binding activity, but also enables BbtPGRP3 to gain a five-fold increase of amidase activity towards the Lys-type PGNs, leading to a significantly broadened substrate spectrum. Together, we propose that modular evolution via domain shuffling combined with gene horizontal transfer makes BbtPGRP1~3 novel PGRPs of augmented catalytic activity and broad recognition spectrum.

Crystal structures and catalytic mechanism of theC-methyltransferase Coq5 provide insights into a key step of the yeast coenzyme Q synthesis pathway

Saccharomyces cerevisiaeCoq5 is anS-adenosyl methionine (SAM)-dependent methyltransferase (SAM-MTase) that catalyzes the onlyC-methylation step in the coenzyme Q (CoQ) biosynthesis pathway, in which 2-methoxy-6-polyprenyl-1,4-benzoquinone (DDMQH2) is converted to 2-methoxy-5-methyl-6-polyprenyl-1,4-benzoquinone (DMQH2). Crystal structures of Coq5 were determined in the apo form (Coq5-apo) at 2.2 Å resolution and in the SAM-bound form (Coq5-SAM) at 2.4 Å resolution, representing the first pair of structures for the yeast CoQ biosynthetic enzymes. Coq5 displays a typical class I SAM-MTase structure with two minor variations beyond the core domain, both of which are considered to participate in dimerization and/or substrate recognition. Slight conformational changes at the active-site pocket were observed upon binding of SAM. Structure-based computational simulation using an analogue of DDMQH2enabled us to identify the binding pocket and entrance tunnel of the substrate. Multiple-sequence alignment showed that the residues contributing to the dimeric interface and the SAM- and DDMQH2-binding sites are highly conserved in Coq5 and homologues from diverse species. A putative catalytic mechanism of Coq5 was proposed in which Arg201 acts as a general base to initiate catalysis with the help of a water molecule.

Adsorption of methylene blue onto activated carbon produced from tea (Camellia sinensis L.) seed shells: kinetics, equilibrium, and thermodynamics studies

Tea (Camellia sinensis L.) seed shells, the main byproduct of the manufacture of tea seed oil, were used as precursors for the preparation of tea activated carbon (TAC) in the present study. A high yield (44.1%) of TAC was obtained from tea seed shells via a one-step chemical method using ZnCl2 as an agent. The Brunauer-Emmett-Teller (BET) surface area and the total pore volumes of the obtained TAC were found to be 1530.67 mg(2)/g and 0.7826 cm(3)/g, respectively. The equilibrium adsorption results were complied with Langmuir isotherm model and its maximum monolayer adsorption capacity was 324.7 mg/g for methylene blue. Adsorption kinetics studies indicated that the pseudo-second-order model yielded the best fit for the kinetic data. An intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step. Thermodynamics studies revealed the spontaneous and exothermic nature of the sorption process. These results indicate that tea seed shells could be utilized as a renewable resource to develop activated carbon which is a potential adsorbent for methylene blue.

[Study on the mortality and risk factors among HIV-infected individuals during 1989 - 2011 in Dehong prefecture, Yunnan province]

OBJECTIVE

To examine the mortality and risk factors among HIV-infected patients during 1989 - 2011 in Dehong prefecture, Yunnan province.

METHODS

All HIV-infected patients reported during 1989 - 2011 in Dehong prefecture who held local residency were included in the study. Mortality rates and cumulative survival rates were calculated. Multiple regression analysis under Cox proportional hazard model was conducted to examine the risk factors for deaths.

RESULTS

A total of 13 006 HIV-infected patients were included in this study including 73.2% males, 79.1% peasants and 48.7% married at the time of reporting. 64.5% of the patients were ethnic minorities, and 68.7% were illiterate or having received only primary school education. All the patients were followed-up for a total of 55 962.30 person-years with 4648 patients died, with overall mortality rate as 8.31/100 person-years. The mortality rate had been increasing from 1990 to 2004 but decreasing since 2005. The average survival time since the identification of HIV infection was 9.48 years overall, and was 16.65 years for those having received antiretroviral treatment (ART) and 7.67 years for those without ART. Data from multiple regression analysis indicated that ART and socio-demographic characteristics such as age, gender, ethnicity, occupation, marital status, education background etc. were significantly associated with death among HIV-infected patients.

CONCLUSION

The comprehensive AIDS campaigns including ART had significantly reduced the deaths among HIV-infected patients in Dehong prefecture. More efforts on the scaling up program of ART as well as the enhanced management and follow-up program tailored for HIV-infected patients with different socio-demographic characteristics were needed to further reduce the deaths in the area.