刚毛柽柳ThGRF2基因的克隆和渗透胁迫应答分析

14-3-3蛋白通常也称为通用调节因子（general regulatory factors,GRF）,是一类丝氨酸和苏氨酸磷酸化结合蛋白,通过与其他转录因子或信号蛋白相互作用参与调节细胞内基础代谢、信号传导、参与植物生长发育以及环境胁迫应答等一系列生理过程。本研究从刚毛柽柳干旱转录组中克隆获得一条干旱胁迫差异表达的ThGRF2基因。ThGRF2基因CDS片段全长为786 bp,编码261个氨基酸。相对分子质量为29.40 kDa,理论等电点（pI）为4.76。将ThGRF2基因构建到pROK2过表达载体上,瞬时转化刚毛柽柳,渗透胁迫前后生理指标结果显示,渗透胁迫后ThGRF2过表达提高了转基因柽柳的叶绿素含量、SOD和POD活性,降低了丙二醛（MDA）含量、电导率（EL）和失水率,表明ThGRF2基因在刚毛柽柳渗透胁迫应答中起重要作用。为进一步探究刚毛柽柳ThGRF2基因的非生物胁迫耐受性功能奠定基础。     

珠江口桂山岛海域桡足类休眠卵对浮游种群的潜在补充及其影响因素

于2011年7月和2012年8月分2个航次采集珠江口桂山岛海域表层沉积物,首次研究珠江口海域桡足类的休眠卵潜在补充量。结果显示:该海域桡足类休眠卵呈不均匀分布,2011年7月沉积物休眠卵潜在补充量介于1.7×105—1.0×107卵/m3之间,平均值为2.1×106卵/m3;2012年8月沉积物休眠卵潜在补充量介于8.9×104—4.3×106卵/m3之间。呈现防波堤外深水区防波堤内养殖区防波堤外浅水区的分布格局。统计分析显示桡足类休眠卵潜在补充量和沉积物含水率呈极显著正相关(P0.01),和水深呈显著正相关(P0.05),表明水深和沉积物含水量是影响桡足类休眠卵潜在补充量的重要因素。休眠卵不同冷藏时间萌发结果发现:萌发持续时间介于10—36d之间,休眠卵萌发类型均为同步萌发型。萌发休眠卵种类为刺尾纺锤水蚤(Acartia spinicauda)和瘦尾胸刺水蚤(Centropages tenuiremis),表明沉积物中休眠卵是上述两种桡足类水体种群的重要补充。筛绢网孔径50—200μm之间休眠卵萌发量占总萌发量的93%,表明采用50μm和200μm筛绢网来分离桡足类休眠卵具有较好的代表性。     

Inhibition of CYP2B4 by 2-ethynylnaphthalene: evidence for the co-binding of substrate and inhibitor within the active site

2-Ethynylnaphthalene (2EN) is an effective mechanism-based inhibitor of CYP2B4. There are two inhibitory components: (1) irreversible inactivation of CYP2B4 (a typical time-dependent inactivation), and (2) a reversible component. The reversible component was unusual in that the degree of inhibition was not simply a characteristic of the enzyme-inhibitor interaction, but dependent on the size of the substrate molecule used to monitor residual activity. The effect of 2EN on the metabolism of seven CYP2B4 substrates showed that it was not an effective reversible inhibitor of substrates containing a single aromatic ring; substrates with two fused rings were competitively inhibited by 2EN; and larger substrates were non-competitively inhibited. Energy-based docking studies demonstrated that, with increasing substrate size, the energy of 2EN and substrate co-binding in the active site became unfavorable precisely at the point where 2EN became a competitive inhibitor. Hierarchical docking revealed potential allosteric inhibition sites separate from the substrate binding site.     

Inhibition of CYP2B4 by the mechanism-based inhibitor 2-ethynylnaphthalene: inhibitory potential of 2EN is dependent on the size of the substrate

2-Ethynylnaphthalene (2EN) is a mechanism-based inhibitor of CYP2B4 with two components to the inhibition, (1) enzyme inactivation, which requires covalent binding of the 2EN metabolite, and (2) reversible inhibition by 2EN itself. Both inhibitory components were examined using several different CYP2B4 substrates. Preincubation of CYP2B4 with 2EN led to a time-dependent inactivation of each of the CYP2B4-dependent activities examined; however, the ability of 2EN to reversibly inhibit CYP2B4 depended on the substrate employed, which is inconsistent with classical inhibition patterns. The degree 2EN's reversible inhibition was shown not to correlate with the substrate affinity for the active site, but with parameters related to the molecular size of the substrate. The results are consistent with 2EN and the smaller substrates simultaneously fitting in the CYP2B4 active site, leading to very little inhibition. Larger substrates exhibited greater degrees of inhibition because of their inability to co-bind with inhibitor in the active site.     

Body dysmorphic disorder: diagnosis and approach

Body dysmorphic disorder is a psychiatric disease that can be frequently encountered in an aesthetic practice. Body dysmorphic disorder is characterized by a preoccupation with a minimal or nonexistent appearance defect and causes significant distress and interferes with the social life of the patient. The perceived physical anomaly may involve the shape and size of the whole body or may be centered around single units. Body dysmorphic disorder patients are known to request multiple aesthetic procedures that leave them unsatisfied. Only a timely diagnosis will enable the surgeon and staff to adequately address the patient's needs. Body dysmorphic disorder patients cannot be cured with surgery. Diagnostic techniques such as patient interview and observation are presented in this article. With this, the plastic surgeon should be able to diagnose body dysmorphic disorder preoperatively. Using the presented algorithm to approach body dysmorphic disorder patients will avoid disappointment for patients and surgeons alike.     

Identification of novel uracil derivatives incorporating benzoic acid moieties as highly potent Dipeptidyl Peptidase-IV inhibitors

Dipeptidyl Peptidase-IV (DPP-4) is a validated therapeutic target for type 2 diabetes. Aiming to interact with both residues Try629 and Lys554 in S₂′ site, a series of novel uracil derivatives 1a–l and 2a–i incorporating benzoic acid moieties at the N₃ position were designed and evaluated for their DPP-4 inhibitory activity. Structure-activity relationships (SAR) study led to the identification of the optimal compound 2b as a potent and selective DPP-4 inhibitor (IC₅₀?=?1.7?nM). Docking study revealed the additional salt bridge formed between the carboxylic acid and primary amine of Lys554 has a key role in the enhancement of the activity. Furthermore, compound 2b exhibited no cytotoxicity in human hepatocyte LO2 cells up to 50?μM. Subsequent in vivo evaluations revealed that the ester of 2b robustly improves the glucose tolerance in normal mice. The overall results have shown that compound 2b has the potential to a safe and efficacious treatment for T2DM.     

Single-Cell Analysis Reveals a Hair Follicle Dermal Niche Molecular Differentiation Trajectory that Begins Prior to Morphogenesis

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Structural insight into how the human helicase subunit MCM2 may act as a histone chaperone together with ASF1 at the replication fork

MCM2 is a subunit of the replicative helicase machinery shown to interact with histones H3 and H4 during the replication process through its N-terminal domain. During replication, this interaction has been proposed to assist disassembly and assembly of nucleosomes on DNA. However, how this interaction participates in crosstalk with histone chaperones at the replication fork remains to be elucidated. Here, we solved the crystal structure of the ternary complex between the histone-binding domain of Mcm2 and the histones H3-H4 at 2.9 Å resolution. Histones H3 and H4 assemble as a tetramer in the crystal structure, but MCM2 interacts only with a single molecule of H3-H4. The latter interaction exploits binding surfaces that contact either DNA or H2B when H3-H4 dimers are incorporated in the nucleosome core particle. Upon binding of the ternary complex with the histone chaperone ASF1, the histone tetramer dissociates and both MCM2 and ASF1 interact simultaneously with the histones forming a 1:1:1:1 heteromeric complex. Thermodynamic analysis of the quaternary complex together with structural modeling support that ASF1 and MCM2 could form a chaperoning module for histones H3 and H4 protecting them from promiscuous interactions. This suggests an additional function for MCM2 outside its helicase function as a proper histone chaperone connected to the replication pathway.     

PET Index of Bone Glucose Metabolism (PIBGM) Classification of PET/CT Data for Fever of Unknown Origin Diagnosis

Objectives

Fever of unknown origin (FUO) remains a challenge in clinical practice. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is helpful in diagnosing the etiology of FUO. This paper aims to develop a completely automatic classification method based on PET/CT data for the computer-assisted diagnosis of FUO.

Methods

We retrospectively analyzed the FDG PET/CT scan of 175 FUO patients, 79 males and 96 females. The final diagnosis of all FUO patients was achieved through pathology or clinical evaluation, including 108 normal patients and 67 FUO patients. CT anatomic information was used to acquire bone functional information from PET images. The skeletal system of FUO patients was classified by analyzing the standardized uptake value (SUV) and the PET index of bone glucose metabolism (PIBGM). The SUV distributions in the bone marrow and the bone cortex were also studied in detail.

Results

The SUV and PIBGM of the bone marrow only slightly differed between the FUO patients and normal people, whereas the SUV of whole bone structures and the PIBGM of the bone cortex significantly differed between the normal people and FUO patients. The method detected 43 patients from 67 FUO patients, with sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 64.18%, 95%, 93.48%, 72.73%, and 83.33%, respectively.

Conclusion

The experimental results demonstrate that the study can achieve automatic classification of FUO patients by the proposed novel biomarker of PIBGM, which has the potential to be utilized in clinical practice.