Systematics of Mukdenia and Oresitrophe (Saxifragaceae): Insights from genome skimming data

Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. The taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. To address this, we produced plastid and mitochondrial data using genome skimming for Mukdenia acanthifolia and Mukdenia rossii, including three individuals of each species. We assembled complete plastomes, mitochondrial CDS and nuclear ribosomal ETS/ITS sequences using these data. Comparative analysis shows that the plastomes of Mukdenia and Oresitrophe are relatively conservative in terms of genome size, structure, gene content, RNA editing sites and codon usage. Five plastid regions that represent hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) are identified within Mukdenia, and six regions (trnH-psbA, petN-psbM, trnM-atpE, rps16-trnQ, ycf1 and ndhF) contain a higher number of species-specific parsimony-informative sites that may serve as potential DNA barcodes for species identification. To infer phylogenetic relationships between Mukdenia and Oresitrophe, we combined our data with published data based on three different datasets. The monophyly of each species (Oresitrophe rupifraga, M. acanthifolia and M. rossii) and the inferred topology ((M. rossii, M. acanthifolia), O. rupifraga) are well supported in trees reconstructed using the complete plastome sequences, but M. acanthifolia and M. rossii did not form a separate clade in the trees based on ETS + ITS data, while the mitochondrial CDS trees are not well-resolved. We found low recovery of genes in the Angiosperms353 target enrichment panel from our unenriched genome skimming data. Hybridization or incomplete lineage sorting may be the cause of discordance between trees reconstructed from organellar and nuclear data. Considering its morphological distinctiveness and our molecular phylogenetic results, we strongly recommend that M. acanthifolia be treated as a distinct species.     

Lipopolysaccharide-induced cytokine production in peripheral blood mononuclear cells: intracellular localization of tumor necrosis factor α and interleukin 1β detected with a three-color immunofluorescence technique

 Lipopolysaccharide (LPS) can induce monocytes to produce various cytokines such as tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β). In the present study, the kinetics of both intracellular and extracellular accumulation of TNFα and IL-1β in LPS stimulated mononuclear cell (MNC) cultures has been determined. A three-color-immunofluorescence technique was used to detect intracellular accumulation of cytokines. Intracellular accumulation of TNFα in monocytes starts shortly after initiation of the culture; i.e., TNFα is detectable after 1 h, reaching a peak level after 3–4 hours with 50–65% of monocytes staining positive. In parallel with its increased intracellular presence, TNFα was also found in the culture supernatant. The intracellular accumulation of IL-1β in monocytes became detectable after 2 h of culture in the presence of LPS. After 4 h, a plateau was reached, with 90% of the monocytes being positive. In parallel, but with a little delay, IL-1β could be detected in the culture supernatant. TNFα and IL-1β can be produced simultaneously in the same monocytes as was shown by a three-color-immunofluorescence technique. It is concluded that TNFα and IL-1β are good parameters for the early measurement of monocyte activation and that both the intracellular accumulation in monocytes and the amount of secreted cytokines can be used for such a purpose. The intracellular accumulation in monocytes can be measured by the three-color-immunofluorescence technique described. Accepted: 27 August 1996     

固定化酵母细胞生产1,6-二磷酸果糖研究

本文研究了固定化酵母细胞制备果糖1,6二磷酸(FDP)的方法及其生产。用卡拉胶包埋方法固定化酿酒酵母(Sacchromyces cerevisae),对含葡萄糖1.0M,磷酸盐0.8M的糖磷液,pH6.5,在37℃下进行磷酸化反应。反复分批转化20天以上,可达到平均产FDPH_427.58mg/ml,最高为59.94mg/ml。用100ml固定化细胞生物反应器连续运转309h,稀释速率D=0.097h~(-1),平均产FDPH_4 21.51mg/ml。20L反应器连续运转,生产能力达到1.7g/h.L。用层析方法制备FDPNa_3结晶粉,提取收率为72.08％,制备质量达到或超过了国内外同类产品的质量要求。     

鹅掌楸雌配子体败育对生殖的影响

胚珠和雌配子体败育是限制鹅掌楸生殖成功的一个重要因素。中国东部和西部鹅掌楸种群在雌配子体发育的各阶段上的败育程度有差异,以西部种群的发育较好。西部分布区较合适的生境促进了胚囊的发育,一定温度和湿度的环境可以活化珠心细胞输送营养物质供给雌配子体发育,提高受精和结籽的能力     

GABAB Receptor-Mediated Effects in Synaptosomes of Lethargic (lh/lh) Mice

Abstract: Previously, we have shown a significant increase in number of GABA_B receptor binding sites in neocortex and thalamus of lethargic ( lh/lh ) mice, a mutant strain exhibiting absence seizures. This study was performed to test our hypothesis that presynaptic GABA_B receptors would inhibit [³H]GABA release to a greater degree in lh/lh mice compared with their nonepileptic littermates (designated +/+). Synaptosomes isolated from neocortex and thalamus of age-matched male lh/lh and +/+ mice were similar in uptake of [³H]GABA. In the neocortical preparation, baclofen dose-dependently inhibited [³H]GABA release evoked by 12 m M KCl, an effect mediated by GABA_B receptors. The maximal inhibition ( I _max) value was significantly greater (80%) in lh/lh than +/+ mice, whereas the IC₅₀ (3 µ M ) was unchanged. In the thalamic preparation, the effect of baclofen (50 µ M ) was 58% less robust in lh/lh mice. Other effects mediated by GABA_B receptors (inhibitions in Ca²⁺ uptake and cyclic AMP formation) were also significantly reduced in thalamic synaptosomes from lh/lh mice. These data suggest a greater presynaptic GABA_B receptor-mediated effect in neocortex and a reduced effect in thalamic nuclei of lh/lh mice. It is possible that selective effects of presynaptic GABA_B receptors on GABA release in neocortex and thalamic nuclei of lh/lh mice may contribute to mechanisms underlying absence seizures.     

应用光敏生物素标记核酸探针鉴定分枝杆菌的研究

用光敏生物素标记非结核分枝杆菌临床分离株及标准分枝杆菌全染色体ＤＮＡ制成探针,与已知标准牛分枝杆菌（ＢＣＧ株）及不同种的非结核分枝杆菌ＤＮＡ杂交,可快速将分支杆菌鉴定到种,同时以大肠埃希氏菌做阴性对照,显示良好的特异性和准确性。此种方法具有鉴定速度快、操作简便、稳定性好及对人体无害等特点,适用于结核杆菌和非结核分枝杆菌的菌种鉴定。     

Crystallization of the first three domains of the human insulin-like growth factor-1 receptor.

The insulin-like growth factor-1 receptor (IGF-1R) is a tyrosine kinase receptor of central importance in cell proliferation. A fragment (residues 1-462) comprising the L1-cysteine rich-L2 domains of the human IGF-1R ectodomain has been overexpressed in glycosylation-deficient Lec8 cells and has been affinity-purified via a c-myc tag followed by gel filtration. The fragment was recognized by two anti-IGF-1R monoclonal antibodies, 24-31 and 24-60, but showed no detectable binding of IGF-1 or IGF-2. Isocratic elution of IGF-1R/462 on anion-exchange chromatography reduced sample heterogeneity, permitting the production of crystals that diffracted to 2.6 A resolution with cell dimensions a = 77.0 A, b = 99.5 A, c = 120.1 A, and space group P2(1)2(1)2(1).     

哺乳动物乳蛋白基因的表达与调控

本文在介绍了乳蛋白基因组结构及进化关系的基础上,就其乳蛋白基因表达的影响因素：顺式调控成分,反式作用因子及激素对表达的诱导进行了讨论,最后就该系统作为生物反应器的开发前景作了展望。     

阳离子诱导大叶藻叶绿体膜中激发能在PSⅡ和PSⅠ之间分配变化的机理(英文)

用Ｃａ２＋ 和胰酶处理大叶藻（Ｚｏｓｔｅｒａ ｍ ａｒｉｎａ）叶绿体膜研究了其类囊体膜多肽成分与Ｍｇ２＋ 诱导其Ｃｈｌａ荧光和类囊体膜表面电荷变化之间的相互关系,观察到：１．在正常的叶绿体膜中,Ｍｇ２＋ 诱导ＰＳⅡ荧光强度的增高与其诱导类囊体膜表面电荷密度的降低密切相关;２．用Ｃａ２＋ 处理这种叶绿体膜,除去类囊体膜表面的３２～３４ ｋＤ多肽对Ｍｇ２＋ 诱导的上述现象无影响;３．如果用胰酶消化Ｃａ２＋ 处理过的叶绿体膜,进一步除去膜表面的２６ ｋＤ多肽,Ｍｇ２＋诱导的这些现象则全部消失。这些实验结果清楚地表明,在大叶藻的叶绿体膜中,类囊体膜表面的２６ ｋＤ 多肽是阳离子诱导这两种相关现象的特异性作用部位。对阳离子调节激发能在ＰＳⅡ和ＰＳⅠ之间分配的机理进行了讨论