Observations on the division characterization of diploid nuclear in <Emphasis Type="Italic">Porphyra</Emphasis> (Bangiales,Rhodophyta)

Nuclear divisions of carpospores, conchocelis and conchospores of Porphyra yezoensis, P. haitanensis, P. katadai var. hemiphylla and P. oligospermatangia from China were investigated. The observations showed diploid chromosome numbers of 2n = 6 for P. yezoensis and P. oligospermatangia, and 2n = 10 for P. haitanensis and P. katadai var. hemiphylla. For all four species, somatic pairing of chromosome sets was observed in late prophase. Sister chromosomes separated at anaphase as mitosis took place in carpospores, conchocelis filamentous cells, conchosporangial branch cells and sporangial cells (conchospore formation). Chromosome configurations of tetrad and ring-shaped in conchospore germination were observed, demonstrating the occurrence of meiosis. The characteristics of diploid nuclear division in 2n = 6 species are the same as those of 2n = 10 species. The influence of somatic pairing on nuclear division of diploid cells in Porphyra was discussed.     

Isolation of enantioselective α-hydroxyacid dehydrogenases based on a high-throughput screening method

To isolate enantioselective α-hydroxyacid dehydrogenases (α-HADHs), a high-throughput screening method was established. 2,4-Dinitrophenylhydrazine solution forms a red-brown complex with ketoacid produced during the α-HADH-mediated oxidation of α-hydroxyacid. The complex can be easily quantified by spectrophotometric measurement at 458?nm. The enantioselectivity of α-HADH in each strain can be measured with this colorimetric method using (R)- and (S)-α-hydroxyacid concurrently as substrates to evaluate the apparent enantioselectivity (E _app). The E _app closely matches the value of true enantioselectivity (E _true) determined by HPLC analysis. With this method, a total of 34 stains harboring enantioselective α-HADHs were selected from 526 potential α-HADH-producing microorganisms. Pseudomonas aeruginosa displayed the highest (S)-enantioselective α-HADH activity. This strain appears promising for potential application in industry to produce (R)-α-hydroxyacids. The method described herein represents a useful tool for the high-throughput isolation of enantioselective α-HADHs.     

包埋法固定化对硫氧化微生物菌群结构和功能的影响

【目的】为探讨包埋法固定化过程对硫氧化菌群硫化物去除能力及菌群微生物群落结构的影响,【方法】以聚乙烯醇-海藻酸钠-活性炭为载体,对硫氧化菌群进行了固定化,并采用富含硫化物的无机盐培养基,对比固定化与非固定化硫氧化菌群对硫化物的氧化去除能力。同时,利用PCR-DGGE技术,探讨硫氧化菌群在固定化前后以及在硫化物氧化去除过程中微生物群落结构变化。【结果】在对硫氧化菌群进行固定化之后,12 h之内对硫化物的最大去除能力从1000 mg/L下降为600 mg/L。硫氧化菌群的微生物群落结构发生了明显变化,但菌群中的硫氧化菌Catenococcus thiocycli未受影响,硫氧化菌Thioclava pacifica在菌群中的地位反而得到了强化。【结论】受制于底物在载体材料中的扩散迁移效率,硫氧化菌群对硫化物的氧化去除能力在固定化之后有所下降。由于不同微生物对固定化形成的微环境的适应能力以及对载体附着能力的不同,固定化对硫氧化菌群的微生物群落结构产生较大影响。     

酒精摄入量对小鼠肠道微生物、酶活性和血常规的影响

【背景】酒是影响机体健康的一把"双刃剑",饮酒对机体肠道微生态体系具有重要影响。【目的】研究不同酒精摄入量对小鼠肠道微生物、酶活性及血常规的影响,从肠道微生态和血常规角度探讨饮酒对身体健康的影响及作用机制。【方法】将SPF(Specific pathogen free)级实验小鼠随机分为对照组、低酒精量摄入组、中酒精量摄入组和高酒精量摄入组。对照组给予蒸馏水饮用,其余各组分别给予10%、20%和30%(体积比)的酒精水溶液作为小鼠的唯一饮用水,连续1个月后采集回肠内容物进行微生物和酶活性分析,采集眼球血进行血常规分析。【结果】与对照组相比,低酒精量摄入组小鼠肠道内乳酸菌数量显著增加(P0.05),大肠杆菌和细菌总数显著降低(P0.01或P0.05);高酒精量摄入组小鼠肠道乳酸菌、双歧杆菌数量显著降低(P0.01);与低酒精量摄入组和中酒精量摄入组相比,高酒精量摄入组小鼠肠道木聚糖酶、纤维素酶、蛋白酶和淀粉酶活性显著升高(P0.01);与对照组相比,低酒精量摄入组小鼠的红细胞比容显著降低(P0.05)。【结论】高酒精摄入量小鼠肠道有益菌群数量相对减少,肠道屏障功能受到影响;低酒精摄入量能调节小鼠肠道菌群结构和消化酶相对活性。     

The Physiological Effects of Ethrel on Seedlings of Second Season Rice

Spray of ethrel (1000 ppm)to seedlings of double-cropping second season rice at 5-leaf stage can control plant height and root length, and consequently makes seedlings strong and tough. The ABA content and ethylene released by young seedling were significantly higher than the control. However, there were some changes: cell elongation inhibited, leaf area decreased, and leaf color became dark green, photosynthetic rate increased, translocation of photosynthetate in leaf sheath enhanced, leaf emergence was rapid. The growth of root system and root vigor were though temporarily inhibited, but slightly increased after transplantation. All these are beneficial to seedling quality, the plant growth and development after transplantation, which subsequently bring about positive effects on stimulating early heading and on increasing rice yield.     

Znf179 E3 ligase-mediated TDP-43 polyubiquitination is involved in TDP-43- ubiquitinated inclusions (UBI) (+)-related neurodegenerative pathology

Background

The brain predominantly expressed RING finger protein, Znf179, is known to be important for embryonic neuronal differentiation during brain development. Downregulation of Znf179 has been observed in motor neurons of adult mouse models for amyotrophic lateral sclerosis (ALS), yet the molecular function of Znf179 in neurodegeneration has never been previously described. Znf179 contains the classical C3HC4 RING finger domain, and numerous proteins containing C3HC4 RING finger domain act as E3 ubiquitin ligases. Hence, we are interested to identify whether Znf179 possesses E3 ligase activity and its role in ALS neuropathy.

Methods

We used in vivo and in vitro ubiquitination assay to examine the E3 ligase autoubiquitination activity of Znf179 and its effect on 26S proteasome activity. To search for the candidate substrates of Znf179, we immunoprecipitated Znf179 and subjected to mass spectrometry (MS) analysis to identify its interacting proteins. We found that ALS/ FTLD-U (frontotemporal lobar degeneration (FTLD) with ubiquitin inclusions)-related neurodegenerative TDP-43 protein is the E3 ligase substrate of Znf179. To further clarify the role of E3 ubiquitin ligase Znf179 in neurodegenerative TDP-43-UBI (ubiquitinated inclusions) (+) proteinopathy, the effect of Znf179-mediated TDP-43 polyubiquitination on TDP-43 protein stability, aggregate formation and nucleus/cytoplasm mislocalization were evaluated in vitro cell culture system and in vivo animal model.

Results

Here we report that Znf179 is a RING E3 ubiquitin ligase which possesses autoubiquitination feature and regulates 26S proteasome activity through modulating the protein expression levels of 19S/20S proteasome subunits. Our immunoprecipitation assay and MS analysis results revealed that the neuropathological TDP-43 protein is one of its E3 ligase substrate. Znf179 interactes with TDP-43 protein and mediates polyubiquitination of TDP-43 in vitro and in vivo. In neurodegenerative TDP-43 proteinopathy, we found that Znf179-mediated polyubiquitination of TDP-43 accelerates its protein turnover rate and attenuates insoluble pathologic TDP-43 aggregates, while knockout of Znf179 in mouse brain results in accumulation of insoluble TDP-43 and cytosolic TDP-43 inclusions in cortex, hippocampus and midbrain regions.

Conclusions

Here we unveil the important role for the novel E3 ligase Znf179 in TDP-43-mediated neuropathy, and provide a potential therapeutic strategy for combating ALS/ FTLD-U neurodegenerative pathologies.

     

TRIM46 activates AKT/HK2 signaling by modifying PHLPP2 ubiquitylation to promote glycolysis and chemoresistance of lung cancer cells

The incidence of lung cancer is increasing worldwide. Although great progress in lung cancer treatment has been made, the clinical outcome is still unsatisfactory. Tripartite motif (TRIM)-containing proteins has been shown to be closely related to tumor progression. However, the function of TRIM46 in lung cancer is largely unknown. Here, TRIM46 amplification was found in lung adenocarcinoma (LUAD) tissues and TRIM46 amplification was significantly associated with a poor survival rate. Overexpression of wild type TRIM46 increased the proliferation of LUAD cells and glycolysis, promoted xenografts growth, and enhanced cisplatin (DDP) resistance of LUAD cells via increased ubiquitination of pleckstrin homology domain leucine-rich repeat protein phosphatase 2 (PHLPP2) and upregulation of p-AKT. In contrast, overexpression of RING-mutant TRIM46 did not show any effects, suggesting the function of TRIM46 was dependent on the E3 ligase activity. Furthermore, we found that TRIM46 promoted LUAD cell proliferation and DDP resistance by enhancing glycolysis. PHLPP2 overexpression reversed the effects of TRIM46 overexpression. Amplification of TRIM46 also promoted LUAD growth and enhanced its DDP resistance in a patient-derived xenograft (PDX) model. In conclusion, our data highlight the importance of TRIM46/PHLPP2/AKT signaling in lung cancer and provide new insights into therapeutic strategies for lung cancer.Subject terms: Cancer, Biomarkers     

Crystal structure of R22L trichosanthin

Ｔｒｉｃｈｏｓａｎｔｈｉｎ(ＴＣＳ)ｉｓａｎｉｍｐｏｒｔａｎｔｍｅｍｂｅｒｏｆｒｉｂｏｓｏｍｅｉｎａｃｔｉｖａｔｉｎｇｐｒｏｔｅｉｎｓ[1].ＩｔｐｏｓｓｅｓｓｅｓＮｇｌｙｃｏｓｉｄａｓｅａｃｔｉｖｉｔｙｒｅｍｏｖｉｎｇａｄｅｎｉｎｅ(ＡＤＥ)ａｔｐｏｓｉｔｉｏｎＡ4324ｏｆ28ＳｒＲＮＡ[2].ＴｈｅａｃｔｉｖｅｐｏｃｋｅｔｏｆＮｇｌｙｃｏｓｉｄａｓｅｈａｓｂｅｅｎｅｓｔａｂｌｉｓｈｅｄｔｈｒｏｕｇｈｔｈｅｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｓｏｆＴＣＳ,αＭＭＣａｎｄｒｉｃｉｎａｎｄａｓｓａｙｏｆｍｕｔａｎｔｓ…     

线虫C.elegans神经发育中轴突引导的调控机制

美丽小杆线虫（Ｃａｅｎｏｒｈａｂｄｉｔｉｓｅｌｅｇａｎｓ）是一种微小的土壤线虫［１］,自胚胎发育成１ｍｍ长的成虫只需三天,结构简单,雌雄同体,由９５９个体细胞构成。但这９５９个体细胞分化出了各种主要的组织类型,包括肌肉、神经元、肠道、上皮等。并且在其...