花色素苷形成中的基因表达和调控

介绍了花色素苷结构基因表达中两大类转录因子,即CI/PI和R/B基因家族和它们对花色素苷生物合成调控的研究进展。     

Combined treatment of rituximab,idarubicin, dexamethasone,cytarabine, methotrexate with radiotherapy for primary central nervous system lymphoma

The overall response rates and long‐term survival of primary central nervous system lymphoma (PCNSL) are still significantly inferior to the results achieved in similar subtypes of extranodal non‐Hodgkin's lymphoma. It is clearly necessary to investigate new therapeutic methods on PCNSL. We encountered three patients histologically documented PCNSL as diffuse large B‐cell lymphoma (DLBCL). They were treated with R‐IDARAM which comprised rituximab, idarubicin, dexamethasone, cytarabine and methotrexate. Patient 1 received stereotactic brachytherapy (SBT) prior to chemotherapy performed with iodine‐125 seeds (cumulative therapeutic dose 50 Gy). After six cycles of R‐IDARAM at 3‐weekly intervals, radiotherapy was applied at a dosage of 2000–4000 cGy in conventional schedule (180 or 200 cGy/day) to whole brain or spinal cord in all patients. Complete remission (CR) was achieved after first two cycles of R‐IDARAM in all patients. All three patients remained in CR at the time of this report with a median duration of follow‐up of 23 months (ranging from 13 to 41 months). Three patients have been alive for 41, 13, 16 months respectively until now. The patient with the longest survival time was the one given SBT prior to chemotherapy. This study suggests that R‐IDARAM combining with radiotherapy maybe a high effective regimen in PCNSL patients especially those with primary central nervous system DLBCL. A comprehensive treatment combining internal radiotherapy by SBT, modified R‐IDARAM and followed reduced external radiotherapy may be a new treatment concept for PCNSL with higher efficiency and lower toxicity.     

An H-2 linked difference in the binding of dexamethasone to murine hepatic cytosol receptor a possible role of endogenous modifier(s)

The binding of dexamethasone to its receptor in hepatic cytosol preparations from pregnant mice of four congenic and recombinant strains, C57BL/10, B10.A, B10.A(2R) and B10.A(5R), which have almost identical genetic backgrounds other than the H-2 complex, on day 12 of gestation was analyzed by plotting the binding of ligand against cytosol concentration. The plots of C57BL/10 and B10.A(5R) mice were straight lines, but those of the strains B10.A and B10.A(2R) were upward concave curves. The curvature probably did not result from denaturation of the receptor, as indicated by the time course of the dexamethasone binding and by the fact that at a lower concentration of the ligand, at which the receptor would be less stable, there was less curvature than at a higher concentration of the ligand. The curvature can be explained by the presence of endogenous modifier(s) using an analogy from enzymology. Mathematical analysis, partial removal of the modifier(s) by gel filtration, and mixing of the cytosols from the two types of strains indicated the presence of an unsaturated amount of a modifier(s) in the cytosol of the B10.A and B10.A(2R) strains, and the presence of a saturated amount in the cytosol of the c57BL/10 and B10.A(5R) strains. Thus, the H-2 complex contains a gene(s) which regulates the level of a modifier(s) in hepatic cytosol which affects the binding of glucocorticoid to its hepatic cytosolic receptor.     

Pre-exposure to UV irradiation increases the transfer frequency of the IncJ conjugative transposon-like elements R391, R392, R705, R706, R997 and pMERPH and is recA+ dependent

The enteric conjugative transposon-like IncJ elements R391, R392, R705, R706 and pMERPH, all demonstrated increased conjugative transfer upon UV irradiation. The transfer frequency increased on average from its basal rate of 10(-5) to 10(-3) per recipient, upon pre-exposure to UV irradiation. However, the transfer frequency of R997, which was higher than the other IncJ elements at 10(-3) per donor, showed a smaller increase. This effect was shown to be recA+ dependent in all cases. Using PCR primers directed outwards from the ends of the integrated R391 element it was observed that a circular intermediate of the element forms within the host, which has been proposed to be a transfer intermediate. Using real-time PCR, it was determined that the amount of the circular intermediate produced increased substantially upon UV irradiation.     

Calcium efflux associated with encystment of Phytophthora palmivora zoospores

Zoospores of the fungus $\text{Phytophthora palmivora}$, pre-labeled with ⁴⁵Ca, excreted up to 30% of their total ⁴⁵Ca when stimulated to encyst. Excretion was essentially completed within 90 sec of the application of the stimulus. Encystment of the population was completed within 5 min. Four different stimuli were used: pectin addition (420 μg ml^?1), Sr²⁺ addition (5 mM), cyclic AMP addition (6.7 mM) and mechanical agitation. The kinetics and amount of Ca excretion were essentially the same in each case. The calcium ionophore A23187 increased the rate of ⁴⁵Ca uptake by motile zoospores, incubated in 100 μM CaCl₂, but did not induce encystment under these conditions. The ionophore did not induce ⁴⁵Ca efflux from pre-labeled zoospores. Incubation in EGTA and in K⁺ failed to induce either encystment or ⁴⁵Ca excretion. We conclude that rapid excretion of a significant proportion of the zoospore calcium is linked to the early stage of stimulus-induced encystment, and that this comes from an intracellularly located, non-cytoplasmic source, such as the peripheral vesicles, but that changes in cellular Ca²⁺ are not necessarily the single controlling factor in the induction of encystment.     

Characterization of a (Ca2+ + Mg2+)-ATPase activator bound to human erythrocyte membranes

Incubation of human erythrocyte ghosts with an equal volume of 0.2 mM EDTA in isotonic KCl decreased both the activity and Ca2+ sensitivity of the (Ca2+ + Mg2+)-ATPase remaining associated with the membrane. Readdition of the EDTA-extract activated the (Ca2+ + Mg2+)-ATPase activity. The activator activity was trypsin sensitive, heat stable and retained by a phenothiazine affinity column, consistent with properties expected of calmodulin. However, unlike calmodulin, the activity was not retained by DEAE Sephadex A-50 and it eluted from Sephacryl S-200 as heterogeneous peaks of activator activity of apparent molecular weight between 107,000 and 178,000. Nevertheless, the activator in the EDTA extract both before and after gel filtration contained calmodulin, as determined by radioimmunoassay and by its activation of calmodulin - deficient phosphodiesterase. SDS-gel electrophoresis of the activator isolated by gel filtration showed a protein of Mr 56,000 in addition to a low molecular weight protein corresponding to calmodulin. It is suggested that the red cell membrane contains a calmodulin binding protein which tightly binds calmodulin as a polymeric complex in a Ca2+-independent manner.     

Analysis of most common mutations R778G, R778L, R778W, I1102T and H1069Q in Indian Wilson disease patients: Correlation between genotype/phenotype/copper ATPase activity

The present study was intented to estimate the frequencies of the most common mutations (R778L, R778W, R778G, I1102T and H1069Q) of ATP7B in Indian Wilson disease (WD) population and to explore the correlation between genotype/phenotype and copper ATPase activity. A total of 33 WD patients and their family members from North West states of India were examined. The H1069Q, R778W and R778L mutations were absent in these WD patients. R778W and I1102T mutations were present in 36% of WD patients. Family analysis for these mutations using PCR-RFLP documented 5 carriers and 2 asymptomatic WD patients. The copper ATPase activity in WD patients was significantly reduced (50%) than that of control individuals. No significant difference was observed in copper stimulated ATPase activity between homozygous (R778W/R778W, I1102T/I1102T) and compound heterozygous (R778W/unknown mutation, I1102T/unknown mutation) WD patients. Serum ceruloplasmin, serum copper levels were significantly lower in homozygous WD patients than that of compound heterozygous. However, no significant difference was observed in liver copper contents between heterozygous and homozygous patients. In conclusion, the data suggest that R778W and I1102T are most common mutations and provide the basis of genetic (PCR-RFLP) diagnostic tool for Indian WD patients as well as in siblings/parents where biochemical parameters are ambiguous.     

MTD-like motif of a BH3-only protein,BNIP1, induces necrosis accompanied by an intracellular calcium spike

The mitochondrial targeting domain (MTD) of Noxa has necrosis-inducing activity when conjugated with cell-penetrating peptide (CPP). In this study, we report another MTD-like motif, B1MLM, found in BNIP1, a pro-apoptotic BH3-only protein found in the endoplasmic reticulum membrane. The B1MLM peptide, conjugated with CPP, induced necrosis in a way similar to that of R8:MTD. R8:B1MLM caused an intracellular calcium spike, mitochondrial reactive oxygen species generation, and mitochondrial fragmentation. The cytosolic calcium spike was likely due to the opening of the mitochondrial permeability transition pore.     

靶向B细胞并特异结合其分泌IL-10的重组融合蛋白的构建、表达和初步鉴定 *

目的:CD19单链抗体可变区(single-chain fragment variable)sc Fv能特异性识别结合B细胞表面的CD19分子,白细胞介素-10(interleukin-10,IL-10)是调节性B细胞(Breg)的主要特征之一。旨在构建CD19sc Fv和IL-10受体1(IL-10R1)胞外段的重组融合蛋白,拟用该融合蛋白捕捉和封闭Breg细胞分泌的IL-10。方法:CD19sc Fv和IL-10R1胞外段克隆到p ET-28a原核质粒上,E.coli BL21(DE3)工程菌表达蛋白通过镍柱富集和纯化蛋白,SDS-PAGE和Western blot对表达蛋白进行鉴定,Pull down实验验证蛋白与CD19分子和IL-10细胞因子的结合。结果:成功表达CD19sc Fv-IL-10R1融合蛋白,该融合蛋白能在体外同时结合CD19和IL-10分子。结论:CD19sc Fv-IL-10R1融合蛋白在体外可以同时结合CD19分子和IL-10分子,具有潜在应用前景可作为特异性抑制Breg的生物小分子。     

国产湖瓜草,球柱草和芙兰草三属果皮微形态特征初探

首次对国产莎草科湖瓜草属、球柱草属和芙兰草属植物的果皮微形态特征进行了扫描电镜的比较观察。结果表明,上述三属果皮纹饰有三种类型：即网状纹饰、疣状纹饰和复合纹饰。其微形态特征存在着明显的种间区别,可为种的划分提供重要依据。研究结果为上述三属植物的分类提供新的佐证,亦为系统演化和亲缘关系的研究提供有价值的资料。     

Design,synthesis, and biological evaluation of a small molecule oral agonist of the glucagon-like-peptide-1 receptor

An absolute or relative deficiency of pancreatic β-cells mass and functionality is a crucial pathological feature common to type 1 diabetes mellitus and type 2 diabetes mellitus. Glucagon-like-peptide-1 receptor (GLP1R) agonists have been the focus of considerable research attention for their ability to protect β-cell mass and augment insulin secretion with no risk of hypoglycemia. Presently commercially available GLP1R agonists are peptides that limit their use due to cost, stability, and mode of administration. To address this drawback, strategically designed distinct sets of small molecules were docked on GLP1R ectodomain and compared with previously known small molecule GLP1R agonists. One of the small molecule PK2 (6-((1-(4-nitrobenzyl)-1H-1,2,3-triazol-4-yl)methyl)-6H-indolo[2,3-b]quinoxaline) displays stable binding with GLP1R ectodomain and induces GLP1R internalization and increasing cAMP levels. PK2 also increases insulin secretion in the INS-1 cells. The oral administration of PK2 protects against diabetes induced by multiple low-dose streptozotocin administration by lowering high blood glucose levels. Similar to GLP1R peptidic agonists, treatment of PK2 induces β-cell replication and attenuate β-cell apoptosis in STZ-treated mice. Mechanistically, this protection was associated with decreased thioredoxin-interacting protein expression, a potent inducer of diabetic β-cell apoptosis and dysfunction. Together, this report describes a small molecule, PK2, as an orally active nonpeptidic GLP1R agonist that has efficacy to preserve or restore functional β-cell mass.     

Transmission,infectivity, and neutralization of a spike L452R SARS-CoV-2 variant

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大黄属3种大黄植物不同部分蒽醌含量的测定与比较

采用C18反相柱高效液相色谱方法分离、外标法定量对大黄属掌叶组唐古特大黄、波叶组波叶大黄、穗序组穗序大黄的根（及根茎）、叶片、叶柄、主茎四部分的芦荟大黄素、大黄酸、大黄素、大黄酚4种游离和结合蒽醌的含量进行了测定和比较。结果表明：唐古特大黄中,叶片中的游离蒽醌含量高于其它部分,游离蒽醌总量地上部分远高于地下部分;结合蒽醌则根中最高,蒽醌总量地下部分远高于地上部分。波叶大黄和穗序大黄中,游离和结合蒽醌均为根中最高,穗序大黄蒽醌总量地下部分远高于地上部分,而波叶大黄中,游离蒽醌总量地上部分高于地下部分,结合蒽醌总量地上部分与地下部分相差不大,地上部分略高于地下部分。     

Identification and Characterization of a Mycobacterial (2R,3R)-2,3-Butanediol Dehydrogenase

Bacterial strain B-009, capable of using racemic 1,2-propanediol (PD), was identified as a rapid-growing member of the genus Mycobacterium. The strain is phylogenetically related to M. gilvum, but has slightly different physiological characteristics. An NAD⁺-dependent enantioselective alcohol dehydrogenase, which acts on R-PD, was purified from the strain. The enzyme was a homodimer of a peptide coded by a 1047-bp gene (mbd1). A highly conserved sequence for medium-chain dehydrogenase/reductases with a preference for secondary alcohols was found in the gene. Hydroxyacetone was produced from R-PD by an enzymatic reaction, indicating that position 2 of the substrate was oxidized. The enzyme activity was highest for (2R,3R)-2,3-butanediol (R,R-BD), enabling the enzyme to be identified as (2R,3R)-2,3-butanediol dehydrogenase (R,R-BD-DH). A homology search revealed M. gilvum, M. vanbaalenii, and M. semegmatis to have ORFs similar to mbd1, suggesting the widespread distribution of genes encoding R,R-BD-DH among mycobacterial strains.     

粘、易型1B/1R小麦雄性不育系产生单倍体的遗传机理及育性恢复性能的研究

调查了ms(Ae.kotschyi)-77(2)和ms(Ae.variabilis)-77(2)低、高世代和在转育、组配中单倍体频率的变化趋势及在不同胞质间、核型间存在的变异。结果表明:(1)粘、易型1B/1R小麦雄性不育系产生单倍体的遗传机理是由于1B/1R卵细胞与粘、易胞质的专一互作,并在花粉蒙导下而导致孤雌生殖的结果;(2)1B·1B/1R杂合核型比1B/1R·1B/1R纯合核型产生的单倍体频率高,1B/1R·1B/1R纯合核型世代间单倍体诱导频率相对稳定;(3)在同一核背景下,诱导单倍体频率粘质高于易质;(4)用不同来源的1B/1R易位系来转育粘、易型不育系及用不同核型的父本与其组配杂种,诱导单倍体频率明显不同;依此差异进行亲本选择,分别可选出与组配出不产生或很少产生单倍体的粘、易型1B/1R不育系和F_1杂种。此外,分析了粘、易型1B/1R不育系一般恢复度不高的内在原由,认为与1B·1B/1R杂合核型中的易位染色体在减数分裂中能否正常联会配对直接相关。     

A Putative Calcium-Permeable Cyclic Nucleotide-Gated Channel, CNGC18, Regulates Polarized Pollen Tube Growth

A tip-focused Ca^2＋ gradient is tightly coupled to polarized pollen tube growth, and tip-localized influxes of extracellular Ca^2＋ are required for this process. However the molecular identity and regulation of the potential Ca^2＋ channels remains elusive. The present study has implicated CNGC18 （cyclic nucleotide-gated channel 18） in polarized pollen tube growth, because its overexpression induced wider and shorter pollen tubes. Moreover, CNGC18 overexpression induced depolarization of pollen tube growth was suppressed by lower extracellular calcium （[Ca^2＋]ex）. CNGC18-yellow fluorescence protein （YFP） was preferentially localized to the apparent post-Golgi vesicles and the plasma membrane （PM） in the apex of pollen tubes. The PM localization was affected by tip-localized ROP1 signaling. Expression of wild type ROP1 or an active form of ROP1 enhanced CNGC18-YFP localization to the apical region of the PM, whereas expression of RopGAP1 （a ROP1 deactivator） blocked the PM localization. These results support a role for PM-Iocalized CNGC18 in the regulation of polarized pollen tube growth through its potential function in the modulation of calcium influxes.