杨树受机械损伤与光肩星天牛危害的防御性反应

杨树是我国“三北”地区防护林建设的主栽树种,自20世纪70年代以来长期受到光肩星天牛的严重危害。北抗杨对光肩星天牛有一定的抗性,但产生抗性的生化机制尚不清楚。本研究采用试剂盒法与高效液相色谱法以未受害、机械损伤、虫害北抗杨为研究材料,对其树皮和木质部中的次生代谢产物和防御酶含量进行检测,以探索其抗性机制。结果表明,北抗杨受到机械损伤和光肩星天牛危害后其反应不同:1)次生代谢产物,北抗杨受到机械损伤后,树皮中的水杨苷和白杨甙含量显著上升,槲皮苷含量降低;而受光肩星天牛危害后,树皮中的水杨苷和槲皮苷含量显著上升,白杨甙含量无显著变化。机械损伤的北抗杨木质部总酚含量高于虫害与未受害木质部,后两者间无显著差异;光肩星天牛危害的北抗杨木质部白杨甙和亚麻木酚素含量高于机械损伤木质部与未受害木质部。遭受机械损伤与虫害后北抗杨木质部的总酚苷含量显著高于未受害木质部。2)防御酶活性分析表明,与未受害北抗杨树皮相比,受到机械损伤与虫害后的树皮苯丙氨酸解氨酶(PAL)活性显著升高,但两者间无差异;受到机械损伤与虫害后的树皮超氧化物歧化酶(SOD)活性高于未受害树皮,且机械损伤树皮高于虫害树皮;北抗杨受机械损伤与虫害后木质部中的过氧化物酶(POD)活性高于未受害木质部,但两者间无差异。3)与未受害北抗杨相比,北抗杨受机械损伤、虫害后部分次生代谢物和防御酶都有不同程度的增加,推测这些物质可能与北抗杨抗逆性反应有关。     

桑黄Zn(II)2Cys6锌簇蛋白转录因子及其在不同碳氮源条件下的表达

Zn(II)2Cys6锌簇蛋白转录因子（C6 zinc）在真菌次生代谢产物合成中发挥重要作用。本研究首先利用本地BLAST,从桑黄Sanghuangporus sanghuang全基因组中获得Zn(II)2Cys6锌簇蛋白转录因子编码基因,并利用生物信息学手段分析编码蛋白保守结构域、一级结构及二级结构,构建蛋白系统发育树,最后利用半定量PCR对它们在不同碳源和氮源培养条件下的表达情况进行检测。结果显示:从桑黄基因组中分析获得的11个Zn(II)2Cys6锌簇蛋白均具有Cy6型锌指基序,属于GAL4型锌簇蛋白转录因子;它们均为不稳定亲水性蛋白,具磷酸化修饰位点,糖基化修饰位点较少或没有,定位于细胞核中;其二级结构主要以无规卷曲和α螺旋为主;系统发育树分析结果显示,桑黄Zn(II)2Cys6锌簇蛋白分为2个大分支,其中Ⅰ类分支转录因子的保守结构域分布于蛋白N-端,Ⅱ类分支转录因子的保守结构域则分布于蛋白C-端;11个桑黄Zn(II)2Cys6锌簇蛋白转录因子在不同培养基培养的菌丝体中呈现差异化表达,其中,肌醇培养基和乳糖培养基能够有效促进大部分锌簇蛋白转录因子的表达;另外,基因簇分析显示桑黄锌簇蛋白SHCZ4可能是NRPS-PKS杂合基因簇体系的途经特异性转录因子。该结果将为桑黄次生代谢产物合成调控相关转录因子的研究以及潜在次生代谢相关基因簇的挖掘提供参考依据。     

基于代谢组学分析两种萎凋方式对白茶萎凋过程代谢物与品质的影响

基于代谢组学技术,比较室内自然萎凋和空气能萎凋两种萎凋工艺对白茶萎凋过程代谢物与品质的影响。结果表明,不同代谢物对2种萎凋工艺的响应存在差异,体现三种变化规律：第一类代谢物受萎凋工艺影响小,如咖啡碱、表没食子儿茶素和2'-羟基二氢大豆素等;第二类代谢物含量变化速率在空气能萎凋时加快,但其最终含量受影响小,如表没食子儿茶素没食子酸酯、聚酯型儿茶素A和木麻黄素等;第三类代谢物则受萎凋时间影响大,如茶没食子素与奎宁酸等。两种萎凋工艺对白茶品质影响存在差异,自然萎凋下黄酮(醇)糖苷类、儿茶素聚合体等含量更高,这些物质多在萎凋中后期含量提升;空气能萎凋下酚酸、茶氨酸含量更高,这些物质在自然萎凋后期含量大幅下降。萎凋时长是两种萎凋工艺导致代谢物含量差异的重要因素。     

Marine microorganisms as an untapped source of bioactive compounds

The search for novel biologically active molecules has extended to the screening of organisms associated with less explored environments. In this sense, Oceans, which cover nearly the 67% of the globe, are interesting ecosystems characterized by a high biodiversity that is worth being explored. As such, marine microorganisms are highly interesting as promising sources of new bioactive compounds of potential value to humans. Some of these microorganisms are able to survive in extreme marine environments and, as a result, they produce complex molecules with unique biological interesting properties for a wide variety of industrial and biotechnological applications. Thus, different marine microorganisms (fungi, myxomycetes, bacteria, and microalgae) producing compounds with antioxidant, antibacterial, apoptotic, antitumoral and antiviral activities have been already isolated. This review compiles and discusses the discovery of bioactive molecules from marine microorganisms reported from 2018 onwards. Moreover, it highlights the huge potential of marine microorganisms for obtaining highly valuable bioactive compounds.     

A promising 31P NMR-multivariate analysis approach for the identification of milk phosphorylated metabolites and for rapid authentication of milk samples

A fast and reliable method for the identification of milk from different mammalians was developed by using ³¹P NMR metabolite profile of milk serum coupled to multivariate analysis (PCA and classification models UNEQ, SIMCA and K-NN). Ten milk samples from six different mammalians, relevant to human nutrition (human, cow, donkey, mare, goat, sheep), were analyzed and eight monophosphorylated components were identified and quantified: phosphocreatine (PCr), glycerophosphorylcholine (GPC), glycerophosphorylethanolamine (GPE), N-acetylglucosamine-1-phosphate (NAcGlu-1P), lactose-1-phosphate (Lac-1P), galactose-1-phosphate (Gal-1P), phosphorylcholine (PC), glucose-6-phosphate (Glu-6P). PCA showed interesting clustering based on the animal genus. K-NN can be successfully used to discriminate between donkey and cow samples while UNEQ class-modeling resulted more suitable for compliance verification. Results confirm the natural variability of milk samples among different species. These data highlight the great potentials of NMR/multivariate analysis combined method in the rapid analysis of phosphorylated milk serum metabolites for milk origin assessment and milk adulteration detection.     

γ-Tocopherol biokinetics and transformation in humans

Background: The uptake and biotransformation of γ-tocopherol (γ-T) in humans is largely unknown. Using a stable isotope method we investigated these aspects of γ-T biology in healthy volunteers and their response to γ-T supplementation.

Methods: A single bolus of 100 mg of deuterium labeled γ-T acetate (d²-γ-TAC, 94% isotopic purity) was administered with a standard meal to 21 healthy subjects. Blood and urine (first morning void) were collected at baseline and a range of time points between 6 and 240 h post-supplemetation. The concentrations of d² and d⁰-γ-T in plasma and its major metabolite 2,7,8-trimethyl-2-(b-carboxyethyl)-6-hydroxychroman (-γ-CEHC) in plasma and urine were measured by GC-MS. In two subjects, the total urine volume was collected for 72 h post-supplementation. The effects of γ-T supplementation on α-T concentrations in plasma and α-T and γ-T metabolite formation were also assessed by HPLC or GC-MS analysis.

Results: At baseline, mean plasma α-T concentration was approximately 15 times higher than γ-T (28.3 vs. 1.9 µmol/l). In contrast, plasma γ-CEHC concentration (0.191 µmol/l) was 12 fold greater than α-CEHC (0.016 µmol/l) while in urine it was 3.5 fold lower (0.82 and 2.87 µmol, respectively) suggesting that the clearance of α-CEHC from plasma was more than 40 times that of γ-CEHC. After d²-γ-TAC administration, the d² forms of γ-T and γ-CEHC in plasma and urine increased, but with marked inter-individual variability, while the d⁰ species were hardly affected. Mean total concentrations of γ-T and γ-CEHC in plasma and urine peaked, respectively, between 0–9, 6–12 and 9–24 h post-supplementation with increases over baseline levels of 6–14 fold. All these parameters returned to baseline by 72 h. Following challenge, the total urinary excretion of d²-γ-T equivalents was approximately 7 mg. Baseline levels of γ-T correlated positively with the post-supplementation rise of (d⁰ + d²) – γ – T and γ-CEHC levels in plasma, but correlated negatively with urinary levels of (d⁰ + d²)-γ-CEHC. Supplementation with 100 mg γ-TAC had minimal influence on plasma concentrations of α-T and α-T-related metabolite formation and excretion.

Conclusions: Ingestion of 100mg of γ-TAC transiently increases plasma concentrations of γ-T as it undergoes sustained catabolism to CEHC without markedly influencing the pre-existing plasma pool of γ-T nor the concentration and metabolism of α-T. These pathways appear tightly regulated, most probably to keep high steady-state blood ratios α-T to γ-T and γ-CEHC to α-CEHC.     

PTP1B inhibitory effects of tridepside and related metabolites isolated from the Antarctic lichen Umbilicaria antarctica

The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory natural products, the MeOH extract of the dried sample of the Antarctic lichen Umbilicaria antarctica was found to exhibit significant inhibitory effect, and the bioassay-guided fractionation and purification afforded three related lichen metabolites 1-3. Compounds 1-3 were identified as gyrophoric acid (1), lecanoric acid (2), and methyl orsellinate (3) mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 3.6 ± 0.04 μM, 31 ± 2.7 μM, and 277 ± 8.6 μM, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compound 1 suggested that the compound inhibited PTP1B activity in a non-competitive manner.     

Biomonitoring of workers cleaning up ammunition waste sites

2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT-exposed humans, notable toxic manifestations have included aplastic anaemia, toxic hepatitis, cataracts, hepatomegaly and liver cancer. Therefore, it is important to develop protection measures and to monitor workers involved in the clean-up of ammunition sites. Haemoglobin (Hb) adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urine metabolites of TNT, 4ADNT and 2ADNT were found in 22–50% of the exposed workers, but not in the control group. The exposed workers were wearing protective equipment. The levels of erythrocytes, haemoglobin, creatinine, serum glutamic pyruvic transaminase and lymphocyte levels were significantly lower in the exposed workers than in the non-exposed workers. The levels of blood urea and reticulocytes were significantly higher in the exposed workers than in the non-exposed workers. Headache (26%), mucous membrane irritation (16%), sick leave (18%), lassitude (8%), anxiety (6%), shortness of breath (3%), nausea (5%) and allergic reactions (8%) were reported by the exposed workers. In a further analysis the U-4ADNT levels and the Hb-adduct levels were compared to the blood parameter and the health effects. The blood parameters were not significantly different between the U-4ADNT positive and U-4ADNT-negative group. Headache, mucous membrane irritation, sick leave, lassitude, anxiety, shortness of breath and allergic reactions were statistically not different between the two groups. Also in the workers with Hb-4ADNT adducts no significant negative changes were seen in regards to the changes of the blood parameters or the health effects. According to the results of the present study, it appears that the blood parameter changes and the health effects are more influenced by other factors than by the internal exposure to TNT.