一种自下而上的合成微生物组理性构建策略，用于郫县豆瓣发酵剂设计

【目的】提出一种合成微生物组的理性构建策略,用于构建郫县豆瓣蚕豆醅初始发酵的微生物组合菌剂。【方法】采取自下而上的合成微生物组理性构建策略,以相对丰度、频率和特征向量中心度作为核心微生物属的选择指标,分析确定蚕豆醅发酵核心微生物;设计模拟原位体系的全合成培养基,并利用该培养基快速、稳定地检测核心微生物包括产香性能在内的发酵特征。基于核心微生物的产香互补性能进行双菌组合发酵实验,结合核心微生物之间的生长相互作用,设计三菌组合发酵菌剂并验证其发酵性能。【结果】本研究确定并分离了郫县豆瓣蚕豆醅发酵过程中的 9种核心微生物。检测核心微生物产生的挥发性风味化合物,发现酵母菌类、乳酸菌类和其他类微生物之间存在产香互补关系。然后,结合微生物间的生长抑制关系设计了由乳酸片球菌、肉葡萄球菌及异变假丝酵母组成的三菌组合菌剂。与企业原位发酵样品相比,三菌组合菌剂产生的挥发性化合物数量达到原位样品的63.1%,化合物种类结构较为相似。与原位样品相比,组合菌剂样品氨基酸态氮浓度提升了21.8%。【结论】本研究提出了一种自下而上的合成微生物组理性构建策略,基于此策略设计了郫县豆瓣蚕豆醅发酵组合菌剂。使用该组合菌剂作为起始发酵剂发酵的郫县豆瓣蚕豆醅具有良好的风味谱和优异的氨基酸态氮水平。本研究在合成微生物组构建与发酵食品工艺改造方面具有较大的科学与应用价值。     

Chemical-induced chromatin remodeling reprograms mouse ESCs to totipotent-like stem cells

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The effect of landscape fragmentation and forest continuity on forest floor species in two regions of Denmark

Abstract. Forest species composition was recorded in 82 forests in the Himmerland and Hornsherred regions in Denmark and analysed with respect to isolation (distance to other forests and areas of forest), forest continuity (older or younger than 200 yr), soil pH, tree species composition and seed dispersal groups. Continuity and isolation measures were correlated with forest species richness in Hornsherred. Myrmecochorous, autochorous, anemoballistic and endozoochorous species were markedly fewer in recent than in ancient forests. In Himmerland, patterns were much weaker and few significant correlations were found between forest species richness or different seed dispersal groups and continuity or isolation of the forests. Differences between the two regions may result from less intensive land use, a more humid climate and a smaller species pool with less species with short distance dispersal in Himmerland. Landscape fragmentation therefore appears to limit forest species’recolonization more in Hornsherred than in Himmerland.     

Broad neutralization of SARS-CoV-2 variants by an inhalable bispecific single-domain antibody

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Multiple forms of Vicia faba α-galactosidases and their relationships

Three highly purified α-galactosidases, I, II¹ and II² have been isolated from resting Vicia faba seeds. Form I (MW 160 000) is a tetrame     

Fractionation and characterization of polyadenylated RNA from broad bean meristematic root cells

Several populations of polyadenylated RNA from Vicia faba méristematic root cells were fractionated by stepwise thermal elution from poly(U)-Sepharose following sequential phenol extraction. Analysis of these fractions showed that the size of the poly(A) segment could influence this fractionation, but in some cases other characteristics of the molecule are involved. Evidence was obtained that 45–60% of the nucleotides of plant polyadenylated RNA are in base paired regions, as was previously demonstrated for mammalian mRNA.

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Resume Après extraction séquentielle au phénol des ARN totaux de cellules méristématiques de racine de Fêve, les ARN polyadénylés, fixés sur colonne de poly(U)-Sépharose, sont séparés en plusieurs populations par une élution thermique à 40° et 50° C. L'analyse structurale de ces fractions montre que si la taille du segment des poly(A) joue le principal rôle dans ce partage, d'autres caractéristiques de molécules d'ARN peuvent interférer. Nous montrons de plus pour la première fois que 45 à 60% des nucléotides des ARN polyadénylés végétaux sont engagés dans des structures à double brin, comme c'est le cas dans les ARN polyadénylés animaux.

     

Dynamics of the Nuclear Complement of Giant Cells Induced by Meloidogyne incognita

The total numbers of nuclei in giant cells induced by Meloidogyne incognita in pea, lettuce, tomato, and broad bean were determined. Mature giant cells from pea had the most nuclei per giant cell with a mean of 59 ± 23, lettuce had the fewest with 26 ± 16, and tomato and broad bean were intermediate. The rate of increase in numbers of nuclei for all plant species was greatest during the first 7 days after inoculation. No mitotic activity was observed in giant cells associated with adult nematodes. Number of nuclei per giant cell doubled each day during the period of greatest mitotic activity, but number of total chromosomes per giant cell increased 20-fold per day at the same time. The hypothesis is presented that factor(s) responsible for the polyploid, mulfinucleate condition characteristic of giant cells may be different from factor(s) responsible for aneuploid numbers of chromosome per nucleus or for nuclear aberrations such as the presence of linked nuclei.     

Dispersal of the broad mite,Polyphagotarsonemus latus (Banks) (Heterostigmata: Tarsonemidae), by the greenhouse whitefly,Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae)

The greenhouse whitefly, Trialeurodes vaporariorum (Westwood), (Homoptera: Aleyrodidae) was found to disperse the broad mite, Polyphagotarsonemus latus (Banks) (Heterostigmata: Tarsonemidae). Mite presence on whiteflies was highly aggregated. This is the second whitefly species reported to disperse the broad mite, suggesting some recognition of the insects by P. latus.