光量与球蚜发生关系的研究

在小兴安岭原始林内和采伐迹地上,发现以下几种球蚜:落叶松球蚜(Adelges laricisVall.),落叶松绿球蚜(Sacchiphanles viridis Ratz.)、落叶松红瘿球蚜(S. rosegallis Liet Tsai)、冷杉球蚜(Aphrastasia pectinatae Chol.) 以及红松球蚜(Pineus cembraepinilcoreanus Zhang et Fang),它们在林内分布和大量发生,其原因除了针叶树种类和树木     

Cost-effectiveness evaluation of different control strategies for Clonorchis sinensis infection in a high endemic area of China: A modelling study

Clonorchiasis is an important food-borne parasitic disease caused by Clonorchis sinensis infection. The evaluation of long-term cost-effectiveness of control strategies is important for disease control and prevention. The present study aimed to assess the cost-effectiveness of the three recommended strategies (i.e., WHO, Chinese and Guangdong strategies) and different combinations of commonly used measures (i.e., preventive chemotherapy, information, education, and communication (IEC) and environmental improvement) on clonorchiasis. The study area, Fusha town in Guangdong Province, was a typical high endemic area in China. The analysis was based on a multi-group transmission model of C. sinensis infection. We set the intervention duration for 10 years and post-intervention period for 50 years. The corresponding costs and DALYs were estimated. Strategies with incremental cost-effectiveness ratios (ICERs) less than 1/5 of the willingness-to-pay threshold were identified as highly cost-effective strategies. The optimal control strategy was obtained using the next best comparator method. The ICERs of Guangdong strategy were $172 (95% CI: $143-$230) US for praziquantel and $106 (95% CI: $85-$143) US for albendazole, suggesting the highest cost-effectiveness among the three recommended strategies. For praziquantel, 470 sets of control strategies were identified as highly cost-effective strategies for achieving infection control (prevalence<5%). The optimal strategy consisted of chemotherapy targeted on at-risk population, IEC and environmental improvement, with coverages all being 100%, and with the ICER of $202 (95% CI: $168-$271) US. The results for transmission control (prevalence<1%) and albendazole were obtained with the same procedures. The findings may help to develop control policies for C. sinensis infection in high endemic areas. Moreover, the method adopted is applicable for assessment of optimal strategies in other endemic areas.     

Genetic validation of Aspergillus fumigatus phosphoglucomutase as a viable therapeutic target in invasive aspergillosis

Aspergillus fumigatus is the causative agent of invasive aspergillosis, an infection with mortality rates of up to 50%. The glucan-rich cell wall of A. fumigatus is a protective structure that is absent from human cells and is a potential target for antifungal treatments. Glucan is synthesized from the donor uridine diphosphate glucose, with the conversion of glucose-6-phosphate to glucose-1-phosphate by the enzyme phosphoglucomutase (PGM) representing a key step in its biosynthesis. Here, we explore the possibility of selectively targeting A. fumigatus PGM (AfPGM) as an antifungal treatment strategy. Using a promoter replacement strategy, we constructed a conditional pgm mutant and revealed that pgm is required for A. fumigatus growth and cell wall integrity. In addition, using a fragment screen, we identified the thiol-reactive compound isothiazolone fragment of PGM as targeting a cysteine residue not conserved in the human ortholog. Furthermore, through scaffold exploration, we synthesized a para-aryl derivative (ISFP10) and demonstrated that it inhibits AfPGM with an IC₅₀ of 2 μM and exhibits 50-fold selectivity over the human enzyme. Taken together, our data provide genetic validation of PGM as a therapeutic target and suggest new avenues for inhibiting AfPGM using covalent inhibitors that could serve as tools for chemical validation.     

祁连山典型流域谷地植被斑块演变与土壤性状

植物群落演变与土壤性状变化之间的相互作用和过程研究对于认识生态系统结构和功能演变有着重要的意义.对祁连山谷地灌丛草甸退化演变过程中植物群落物种组成、土壤物理和化学性状特征、及土壤与植被的相互作用进行了研究,结果表明,在祁连山谷地阴坡林线以下较小的空间范围,植被斑块由金露梅群落向金露梅-马蔺群落斑块和马蔺群落斑块演变,植被盖度降低,但物种多样性增加.不同植被斑块之间土壤水分有显著的梯度变化,土壤水分的变化导致植被的退化演替.植被斑块的演变导致土壤性状的明显分异,从金露梅灌丛斑块向金露梅-马蔺群落斑块和马蔺群落斑块演变,土壤容重显著增加,土壤团聚体组成由大粒级的大团聚体(》1mm)破碎为小粒级的大团聚体(1-0.25mm)和微团聚体(《0.25mm),团聚体稳定性降低,表明土壤结构的退化;土壤有机碳含量下降了31.2%和55.9%,干筛各粒级土壤团聚体中有机碳含量金露梅-马蔺群落斑块和马蔺群落斑块显著低于金露梅斑块,土壤团聚体平均重量粒径与有机碳含量存在显著相关,植被退化演变中土壤有机碳的损失部分地由于团聚体的破碎引起;土壤全氮和有效氮不同斑块之间也有显著的差异,植被斑块退化演变使氮的有效性降低;但磷、钾养分对植被变化的响应不敏感.植被的退化演变使土壤团聚体破碎、土壤结构退化,有机碳和全氮含量下降,使其抗侵蚀能力和水源涵养功能显著降低,又进一步加速植被的退化演替.在气候变暖的趋势下,马蔺斑块将进一步向林线逼近,灌丛草甸植被将会进一步退化和萎缩.     

Hemin with Peroxidase Activity Can Inhibit the Oxidative Damage Induced by Ultraviolet A

Excessive reactive oxygen species (ROS), a highly reactive substance that contains oxygen, induced by ultraviolet A (UVA) cause oxidative damage to skin. We confirmed that hemin can catalyze the reaction of tyrosine (Tyr) and hydrogen peroxide (H₂O₂). Catalysis was found to effectively reduce or eliminate oxidative damage to cells induced by H₂O₂ or UVA. The scavenging effects of hemin for other free-radical ROS were also evaluated through pyrogallol autoxidation, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)-scavenging assays, and phenanthroline–Fe²⁺ assays. The results show that a mixture of hemin and tyrosine exhibits strong scavenging activities for H₂O₂, superoxide anion (O₂⁻·), DPPH·, and the hydroxyl radical (·OH). Furthermore, the inhibition of oxidative damage to human skin keratinocyte (HaCaT) cells induced by H₂O₂ or UVA was evaluated. The results show that catalysis can significantly reduce the ratio of cell apoptosis and death and inhibit the release of lactate dehydrogenase (LDH), as well as accumulation of malondialdehyde (MDA). Furthermore, the resistance to apoptosis was found to be enhanced. These results show that the mixture of hemin and tyrosine has a significantly protective effect against oxidative damage to HaCaT cells caused by UVA, suggesting it as a protective agent for combating UVA damage.     

Studying Early Nodulin Gene ENOD40 Expression and Induction by Nodulation Factor and Cytokinin in Transgenic Alfalfa

ENOD40, an early nodulin gene, is expressed following inoculation with Rhizobium meliloti or by adding R. meliloti-produced nodulation (Nod) factors or the plant hormone cytokinin to uninoculated roots. We isolated two MsENOD40 clones, designated MsENOD40–1 and MsENOD40–2, with distinct promoters from an alfalfa (Medicago sativa cv Chief) genomic library. The promoters were fused to the reporter gene uidA (gus), and the constructs were introduced into alfalfa. We observed that the MsENOD40–1 construct was expressed almost exclusively under symbiotic conditions. The MsENOD40–2 construct was transcribed under both symbiotic and nonsymbiotic conditions and in nonnodular and nodular tissues. Both MsENOD40 promoter-gus constructs were similarly expressed as nodules developed, and both were expressed in roots treated with 6-benzylaminopurine or purified Nod factor. However, no blue color was detected in nodule-like structures induced by the auxin transport inhibitor N-1-(naphthyl)phthalamic acid on roots of plants containing the MsENOD40–1 promoter construct, whereas pseudonodules from plants containing the MsENOD40–2 promoter construct stained blue. A 616-bp region at the distal 5′ end of the promoter is important for proper spatial expression of MsENOD40 in nodules and also for Nod-factor and cytokinin-induced expression.     

Aerobic denitrification by novel isolated strain using NO-₂-N as nitrogen source

Biological denitrification reaction can be achieved under aerobic environment. Few aerobic denitrifiers using nitrite as sole nitrogen source were identified. Using nitrite as the sole nitrogen source, this work assessed the denitrification activity of yy7, an aerobic heterotrophic denitrifier identified as Pseudomonas sp. (94% similarity) by 16S rRNA sequencing analysis. The logistic equation describes the cell growth curve, yielding a generation time of 2.9h at an initial 18 mg l(-1)NO(-)?-N. Reduction of NO(-)?-N was primarily achieved during its logarithmic growth phase, and was accompanied by an increase in suspension pH and near complete consumption of dissolved oxygen. Three genes relating to nirK, norB, and nosZ were noted to involve in isolate strain. Isolate yy7 can survive and remove up to 40 mg l(-1)NO(-)?-N and, hence, can be applied as an effective aerobic denitrifier during simultaneous nitrification and denitrification via nitrite processes.     

光学方法分析GABA及GABAA受体在脑干听觉传入通路的作用

目的旨在探讨脑干听觉传入通路中GABA能神经递质及GABAA受体对电刺激位听神经传入冲动的影响.方法使用出生后0～5 d的ddy/ddy小鼠制备脑干切片.脑片经电压敏感染料NK3041染色,电刺激与脑片相连的位听神经残端.使用16×16像素的硅光电二极管阵列测量光学信号.所采集的数据使用ARGUS50/PDA软件分析.结果多部位的光学记录方法显示了从位听神经到耳蜗核和前庭核的兴奋性传导的时间-空间分布.其中每一个光学成分由快峰电位样反应和慢反应组成.抑制性神经递质GABA可降低诱发的光学信号的快反应和慢反应,GABAA受体拮抗剂荷包牡丹碱可增强这些反应.结论16×16像素的硅光电二极管阵列可记录位听神经刺激诱发的多部位光学信号,每一个光学信号含有突触前及突触后电位成分.抑制性神经递质GABA和GJBAA受体拮抗剂可调节光学信号的兴奋性传导.     

The chemiluminescence immunoassay for aflatoxin B1 based on functionalized magnetic nanoparticles with two strategies of antigen probe immobilization

A rapid and sensitive chemiluminescence immunoassay (CLIA) based on magnetic nanoparticles (MNPs) was developed to detect aflatoxin B1 (AFB1), which is a potent carcinogen in nature. We prepared monodisperse MNPs (300 nm in diameter) according to the solvothermal synthesis reaction and the MNPs were coated with silica by the Stöber method. Triethox was used as a one‐step carboxylation reagent, and 3‐aminopropyltriethoxysilane (APTES) an amination reagent, to modify the MNPs. We prepared two types of solid phase antigens using the above synthesized functionalized MNPs coupled with the later prepared AFB1‐oxime active ester and the purchased BSA–AFB1 respectively. 2′,6′‐dimethylcarbonylphenyl‐10‐sulfopropylacridinium‐9‐carboxylate 4′‐N‐hydroxysuccinimide (4′‐NHS) ester (NSP–DMAE–NHS), as a novel luminescent reagent, was used to label anti‐AFB1 antibodies. The two CLIA calibration curves based on the two types of solid phase antigens were obtained and compared. The acquired limit of detection (LOD) was about 0.001 ng/mL for the two functionalized MNPs‐based immunoassays, and the half maximal inhibitory concentration (IC₅₀) was 0.51 ng/mL for the MNPs–AFB1‐based method and 0.72 ng/mL for the MNPs–BSA–AFB1‐based method.