Highly efficient transglycosylation of sialo-complex-type oligosaccharide using <Emphasis Type="Italic">Coprinopsis cinerea</Emphasis> endoglycosidase and sugar oxazoline

Objectives

To establish an efficient method of chemoenzymatic modification for making N-linked oligosaccharide chains of glycoproteins structurally homogeneous, which crucially affects their bioactivities.

Results

Deglycosylated-RNase B (GlcNAc-RNase B; acceptor), sialylglyco (SG)-oxazoline (donor) and an N180H mutant of Coprinopsis cinerea endo-β-N-acetylglucosaminidase (Endo-CC^N180H) were employed. pH 7.5 was ideal for both SG-oxazoline’s stability and Endo-CC’s transglycosylation reaction. The most efficient reaction conditions for producing glycosylated-RNase B, virtually modified completely with sialo-biantennary-type complex oligosaccharide, were: 80 μg GlcNAc-RNase B, 200 μg SG-oxazoline and 3 μg Endo-CC^N180H in 20 μl 20 mM Tris/HCl pH 7.5 at 30 °C for 30–60 min.

Conclusions

This transglycosylation method using SG-oxazoline and Endo-CC^N180H is beneficial for producing pharmaceutical glycoproteins modified with homogenous biantennary-complex-type oligosaccharides.

     

UV light spectral response of photosynthetic photochemical efficiency in alpine mosses

Aims Bryophytes play an important role in primary production in harsh alpine environment. As other alpine plants, the alpine bryophytes are often exposed to stronger UV radiation than lowland plants. Plants growing under high UV radiation may differ from those from low UV regimes in their physiological response to UV radiation. We were to (i) test the hypothesis and to address whether and/or how alpine bryophytes differ in photosynthetic photochemical characteristics in response to UV light and (ii) understand the potential effects of UV radiation on photosynthetic photochemical process in alpine bryophytes.Methods We examined the maximum quantum efficiency of photosystem II (PSII) photochemistry (F v /F m) for two alpine bryophyte species, Distichium inclinatum and Encalypta alpine, from a Kobresia humilis meadow and a Kobresia tibetica wetland, respectively, in Haibei, Qinghai (37°29′N, 101°12′E, altitude 3?250 m), and for a lowland bryophyte, Polytrichum juniperinum, under different spectrum of UV light. Biological spectral weighting function (BSWF) was obtained to evaluate the effect of UV light on the physiological response in these species.Important findings1)?The maximum quantum efficiency of photosystem II photochemistry (F v /F m) declined linearly with the increase of radiation dose in wavelengths from 250 to 420 nm. The effect of UV radiation on F v /F m decreased with higher rate from 250 to 320 nm and from 400 to 420 nm than in UVA range. 2)?The three species from different ecosystems contrasting in altitudes showed similar pattern of UV effectiveness. In comparison with other species reported so far, the moss BSWF was among those with the most modest decrease trend with spectrum effect of UV light 50 times higher at 250 than at 420 nm. 3)?Under the scenario of 16% reduction of stratospheric ozone, the integrated effectiveness from 290 to 345 nm increased only 5%, suggesting that the photochemical activity of the bryophyte PSII is likely to insensitive to O 3 depletion.     

鱼类生物能量学的理论与方法

生物能量学(bioenergetics)是研究能量在生物体内转换的学科.       

Rapid prototyping enzyme homologs to improve titer of nicotinamide mononucleotide using a strategy combining cell-free protein synthesis with split GFP

Engineering biological systems to test new pathway variants containing different enzyme homologs is laborious and time-consuming. To tackle this challenge, a strategy was developed for rapidly prototyping enzyme homologs by combining cell-free protein synthesis (CFPS) with split green fluorescent protein (GFP). This strategy featured two main advantages: (1) dozens of enzyme homologs were parallelly produced by CFPS within hours, and (2) the expression level and activity of each homolog was determined simultaneously by using the split GFP assay. As a model, this strategy was applied to optimize a 3-step pathway for nicotinamide mononucleotide (NMN) synthesis. Ten enzyme homologs from different organisms were selected for each step. Here, the most productive homolog of each step was identified within 24 h rather than weeks or months. Finally, the titer of NMN was increased to 1213 mg/L by improving physiochemical conditions, tuning enzyme ratios and cofactor concentrations, and decreasing the feedback inhibition, which was a more than 12-fold improvement over the initial setup. This strategy would provide a promising way to accelerate design-build-test cycles for metabolic engineering to improve the production of desired products.     

Effect of Sequestosome-1/p62 Expression on Autophagy of Human Periodontal Ligament Fibroblasts Induced by Porphyromonas gingivalis

Russian Journal of Bioorganic Chemistry - Porphyromonas gingivalis is the main pathogen of periodontitis. The purpose of this study was to analyze the effect of p62 protein on P. gingivalis-induced...     

Effects of warming on root diameter,distribution, and longevity in an alpine meadow

Roots form one of the most important carbon (C) pools in alpine ecosystems. Uncertainty about the effects of warming on root dynamics limits our ability to predict how C will transfer between biological and atmospheric pools in alpine regions under global warming. We used a minirhizotron technique to gain a better understanding of the response of alpine plant roots to warming. We looked for effects on root diameter, root depth in the soil, and root lifespan under a controlled asymmetrical warming (1.2/1.7 °C during daytime/nighttime) experiment during the growing season of 2009 in an alpine meadow on the northern Tibetan plateau. Roots became smaller in diameter, moved toward the upper soil layers, and showed significantly shorter lifespans in heated (H) than in unheated (UH) plots. Furthermore, in H treatment plots root lifespan was more strongly influenced by the time of root emergence rather than by root diameter. These results provide evidence that alpine plants may respond to climate change by altering their roots so that they are thinner, distributed shallower and turning over faster, suggesting that soil C flow and nutrient cycling would be accelerated resulting from the fast turnover of fine roots under elevated temperatures.     

Studies of Mycorrhizal Fungi of Chinese Orchids and Their Role in Orchid Conservation in China—A Review

China has over 1,200 species of native orchids in nearly 173 genera. About one fourth of native species are of horticultural merit. Some species are of Chinese medicinal value. In fact, the demand on orchid species with high Chinese medicinal values such as Gastrodia elata, Dendrobium offcinale, along with demands on species of cultural importance, such as those in the genus of Cymbidium, is a major factor causing wild populations to diminish and in some cases, drive wild populations to the brink of extinction. These market demands have also driven studies on the role of mycorrhizal fungi in orchid seed germination, seedling and adult growth, and reproduction. Most of these mycorrhizal studies of Chinese orchids, however, are published in Chinese, some in medical journals, and thus overlooked by the mainstream orchid mycorrhizal publications. Yet some of these studies contained interesting discoveries on the nature of the mycorrhizal relationships between orchids and fungi. We present a review of some of these neglected publications. The most important discovery comes from the mycorrhizal studies on G. elata, in which the researchers concluded that those fungi species required to stimulate seed germination are different from those that facilitate the growth of G. elata beyond seedling stages. In addition, presence of the mycorrhizal fungi associated with vegetative growth of post-seedling G. elata hindered the germination of seeds. These phenomena were unreported prior to these studies. Furthermore, orchid mycorrhizal studies in China differ from the mainstream orchid studies in that many epiphytic species (in the genus of Dendrobium, as medicinal herbs) were investigated as well as terrestrial orchids (mostly in the genus Cymbidium, as traditional horticultural species). The different responses between epiphytic and terrestrial orchid seeds to fungi derived from roots suggest that epiphytic orchids may have a more general mycorrhizal relationship with fungi than do terrestrial orchid species during the seed germination stage. To date, orchid mycorrhizal research in China has had a strongly commercial purpose. We suggest that this continuing research on orchid mycorrhizal relationships are a solid foundation for further research that includes more rare and endangered taxa, and more in-situ studies to assist conservation and restoration of the endangered orchids. Knowledge on the identities and roles of mycorrhizal fungi of orchids holds one of the keys to successful restoration and sustainable use of Chinese orchids.     

肝细胞治疗的新型种子细胞——诱导性多能干细胞

在回顾iPS细胞研究的基础上,针对肝细胞治疗的研究现状,就iPS细胞诱导分化为肝细胞的研究进展及其在肝病细胞治疗中的潜力进行了探讨,并提出了目前面对的主要问题,希望促进iPS细胞在肝病细胞治疗上的应用。     

气候变化对中国大黄花虾脊兰及其传粉者适生区的影响

大黄花虾脊兰(Calanthe sieboldii)是典型的大陆与岛屿间间断分布的兰科物种, 适宜分布气候范围狭窄, 同时依赖特殊的传粉者传粉, 包括黄胸木蜂(Xylocopa appendiculata)、赤足木蜂(X. rufipes)和中华绒木蜂(X. chinensis)等3种木蜂属(Xylocopa)昆虫。本文通过R语言Biomod2程序包建立物种分布模型(SDM), 预测了2050年和2070年时大黄花虾脊兰及其传粉者在3种代表浓度路径(RCP2.6、RCP4.5与RCP8.5)下的分布格局, 以期为该濒危植物的保育提供参考。结果表明: 降水相关变量比温度相关变量对大黄花虾脊兰分布的平均解释率更高, 两者分别为25.4%和13.9%。当前大黄花虾脊兰适生区主要集中在华中和华东地区, 未来适生区的增减主要受到气候情景的影响, 其变化范围为-59.0%到34.7%, 并可能向更高海拔的地区移动; 未来木蜂适生区将净收缩16.4%-19.7%, 且主要向西北和东北移动; 因而两者共同分布的面积占大黄花虾脊兰适生区的比例未来相比当前的90.0%可能下降0.5%-11.4%, 表明大黄花虾脊兰分布可能受到未来气候变化和传粉者分布减少的双重影响, 因此对该物种或类似特化传粉的兰科植物进行保育时应当充分考虑传粉者因素。