金属离子对漆斑菌产胆红素氧化酶的影响

比较了漆斑菌在8种液体培养基中胆红素氧化酶(BOX)产量,发现马铃薯液体培养基(PDB)是最适宜漆斑菌产BOX的培养基。研究了8种常见金属离子对漆斑菌产酶的影响,结果表明钠离子、铜离子可以明显促进BOX产量提高,铜离子效果最强,随着铜离子浓度增加,BOX酶产量可进一步提高,但高浓度的铜离子(1mmol.L-1)会抑制酶产量增加。     

Effect of Bilirubin on Lipid Peroxidation, Sphingomyelinase Activity, and Apoptosis Induced by Sphingosine and UV Irradiation

The effect of bilirubin (BR) on sphingomyelin cycle activity, lipid peroxidation (LPO), and apoptosis induced by sphingosine and UV irradiation has been studied in vivo. Neutral Mg²⁺-dependent sphingomyelinase (SMase) activity and LPO level were monitored in heart, kidney, and liver of mice after administration of BR. BR inhibited both LPO and SMase activities in heart and kidney. BR induced a mild increase in LPO level and moderate increase in lipid contents in liver, consistent with the functional role of liver in both BR and lipid metabolism. BR injected to mice causes simultaneous and unidirectional alterations in both LPO level and SMase activity with a significant (p < 0.05) positive linear correlation between these two parameters. Sphingosine administration results in increased lipid peroxidation in murine liver. Data on DNA fragmentation indicate that exogenous BR may effectively protect thymus cells against sphingosine- and UV-mediated apoptosis. These results have revealed a biochemical association between oxidative stress and BR on one hand and the sphingomyelin cycle and apoptotic cell death on the other hand. Our data show that BR as an antioxidant, due to its effect on the sphingomyelin cycle, can protect membrane lipids against peroxidation and cells against apoptosis induced by various factors.     

Total Hip Arthroplasty: Direct Anterior Approach Versus Posterior Approach in the First Year of Practice

BackgroundThe direct anterior approach (DAA) for total hip arthroplasty (THA) has been popularized as a less invasive technique, however outcomes within the first year of practice after fellowship have not been investigated. The primary aim was to determine differences in complications and outcomes between DAA and posterior approach (PA) in the first year of practice. The secondary aim was to determine if there was a learning curve factor in DAA and PA after fellowship training.MethodsTHA cases performed by two surgeons during their first year of practice were reviewed. Overall, 181 THAs (91 DAA, 90 PA) in 168 patients, were performed. Intraoperative differences (blood loss, operative time), hospital stay, complications, reoperations, and revisions were compared.ResultsOverall surgical complications were similar between DAA and PA (11% vs. 9%, p=0.64), but complication profiles were different: dislocation (1% vs. 4%, p=0.17), intraoperative femoral fracture (2% vs. 1%, p=0.32), postoperative periprosthetic fractures (2% vs. 3%, p=0.64). neuropraxia (3% vs. 0%, p=0.08). There was no difference in rate of reoperation (1% vs. 3%, p=0.31). There was a difference in rate of revision at final follow-up (0% vs. 6%, p=0.02). DAA consisted of longer operative time (111 vs. 99 minutes; p<0.001), however was only significant in the first 50 cases (p<0.001), while the subsequent cases were similar (p=0.31). There was no difference in the first 50 cases compared to the subsequent cases for either approach regarding blood loss, complications, reoperations, or revisions.ConclusionDAA and PA for THA performed within the first year of practice exhibit similarly low complication rates, but complication profiles are different. In our series, PA did demonstrate a higher risk of revision at final follow-up. A learning curve is not unique to the DAA. Both DAA and PA THA exhibited a learning curve in the first 50 cases performed at the start of a surgeon’s practice. Level of Evidence: III     

Sensitive fluorescence in situ hybridization signal detection in maize using directly labeled probes produced by high concentration DNA polymerase nick translation

The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30?kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected.     

Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations

Understanding how wheat (Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate‐resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization‐tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat‐tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared with optimum temperature. The lower unsaturation was predominantly because of lower levels of 18:3 acyl chains and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3‐containing triacylglycerols increased threefold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodelling. Phospholipids containing odd‐numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0‐acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0‐ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, in which some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT.     

秸秆还田方式对东北水稻土理化性质及微生物群落的影响

【目的】研究秸秆还田方式对东北黑土理化性质及微生物群落的影响。【方法】试验周期为2019年12月至2021年10月,秸秆还田采用2种方式： 秸秆直接还田+微生物菌剂WJ(strawdirect return+microbial agent WJ;MD),秸秆堆肥还田+微生物菌剂WJ(straw compost return +microbial agent WJ;MC)。分析土壤肥力、酶活和微生物群落。【结果】分析两种方式土壤有机质(SOM)、腐殖酸(HS)和富里酸有机碳(FA-C)含量,发现秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ分别增加2.28g/kg、7.82g/kg和5.26g/kg。土壤铵态氮(NH4⁺-N)、速效磷(AP)略高于秸秆堆肥还田+微生物菌剂WJ,均在6月份达到峰值。胡敏酸有机碳(HA-C)含量下降。此外,土壤脲酶、转化酶、纤维素酶活性和碱性磷酸酶活性对比发现,秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ分别高8.55%、15.46%、4.35%和6.19%。高通量测序结果显示,秸秆直接还田+微生物菌剂WJ中细菌和真菌的多样性均比秸秆堆肥还田+微生物菌剂WJ丰富。其中Anaerolinea、Bacteroidetes、Pseudomonas为优势细菌,Tausonia、Mrakia、Mrakiella为优势真菌。【结论】秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ更有利于土壤有机质、腐殖酸、土壤酶活性和微生物多样性的增加,这说明秸秆添加WJ菌剂直接还田可以减少有机养分的流失,保持田间土壤肥力。     

Delineation of the European Armillaria species based on the sequences of the internal transcribed spacer (ITS) of ribosomal DNA

Variation within the internal transcribed spacer (ITS) of the ribosomal RNA gene of 15 isolates representing seven European Armillaria species, was examined by sequencing of the PCR-amplified products. The analysis of an 744-bp region showed that the 5.8S gene appeared to be highly conserved in the 15 isolates and in other Basidiomycetes and Ascomycetes, whereas ITS1 and especially ITS2 spacers exhibited polymorphisms due to base substitutions, insertions or deletions of up to eight nucleotides. An initial dendrogram for the full sequence was drawn using cluster analysis (UPGMA), and a tree was constructed using the maximum parsimony method. Both methods indicated that the isolates could be divided into four major groups. One group, consisting of A. ectypa , was distinct from all the other species. Examination of the other groups indicated that A. tabescens and A. mellea were in a separated cluster, with a significant variation between the two isolates of the latter species. A. gallica and A. cepistipes constituted another closely related group distinguishable from A. ostoyae and A. borealis , these latter two species exhibiting the highest similarity. The results are consistent with, and discussed in regard to, the relationships estimated previously by pairing tests, morphological and physiological comparisons, as well as by restriction fragment length polymorphism of the rDNA.     

Alternative parasite development in transmission strategies: how time flies!

Among parasitic platyhelminths with complex life cycles, it has been well documented that transmission opportunities are the main forces shaping the diversity of life‐history traits and parasite developmental strategies. While deviations in the development pathway usually involve shortening of life cycles, their extension may also occur following perception of remaining time by parasites. Polystoma gallieni, the monogenean parasite of Hyla meridionalis, is able to trigger two alternative developmental strategies depending on the physiological stage of the tadpoles upon which larvae attach. The distribution and reproductive outputs of both resulting phenotypes were surveyed to address questions about the dynamics of transmission in natural environments. Because modifications in the completion of life cycles can have drawbacks which may perturb the dynamic equilibrium of the resulting host–parasite systems, experimental infestations were also performed to assess parasite–parasite interactions. Our results suggest that the bladder adult phenotype, which involves transmission between frogs and tadpoles, is supplied secondarily by the branchial phenotype which involves transmission between tadpoles and metamorphs. They also support the occurrence of finely tuned trade‐offs between hosts and parasites and highlight positive trends behind the extension of direct life cycles, in which host‐derived signals account for the remaining time to achieve parasitic transmission.     

A structured analysis of risk to important wildlife elements in three Australian Wildlife Conservancy sanctuaries

Where data and information are lacking, structured expert risk assessments can provide a powerful tool to progress natural resource planning. In many situations, practitioners make informal assessments of risk within small groups that typically constitute employees. In this study, we report on three small (in terms of experts) structured expert‐based risk assessment case studies conducted by expert employees of a not‐for‐profit organisation (Australian Wildlife Conservancy) to demonstrate the utility of the approach. The case studies were carried out for three wildlife sanctuaries managed by AWC: Faure Island, Karakamia and Paruna. The likelihood that a set of direct risk factors would cause management failure for sets of important wildlife elements in the three sanctuaries was elicited from the small group of ecological experts. The analysis was couched in terms of a management aim to not lose species from each wildlife element over the management period of 25 years with current management. The experts believed, in particular, that increasing temperature and decreasing water availability associated with climate change were likely to impact significantly upon the vegetation elements and water‐reliant fauna associated with the sanctuaries. Some vegetation elements were also thought likely to be at risk of over‐grazing, unsuitable fire regimes and, in some cases, disease. In addition to predation by exotic predators at one sanctuary, the experts identified additional direct risk factors for various fauna elements associated with expected changes to the vegetation elements, including reduction in food availability, nesting habitat, and generally important life media. From the risk analyses, a preliminary conceptual model was developed to underpin monitoring and to indicate areas for possible management intervention and research. The case studies demonstrate that even in a small workplace team, structured risk assessments can be efficiently accomplished and can provide expedient and transparent information that effectively captures and aggregates the views of the experts.     

一性连锁Alport综合征中国家系COL4A5基因新突变位点的检测

通过PCR和直接测序的方法,对一性连锁Alport综合征家系17个受检个体的COL4A5基因所有51个外显子及其相邻内含子的DNA序列进行检测。结果发现,在第26外显子2240位点,男患者存在C碱基缺失(2240delc),女患者存在杂合缺失,同时对女患者相应的PCR产物进行克隆和测序以验证PCR测序结果的可靠性,而在正常家系成员和80例对照中均未发现此位点异常,说明2240delc为引起该家系临床病变的突变位点,不是多态性位点。在性连锁Alport综合征中,COL4A5基因的这个单碱基缺失突变位点为首次报道。