Role of aquaporin-7 in the pathophysiological control of fat accumulation in mice

Aquaporins are channels that allow the movement of water across the cell membrane. Some members of the aquaporin family, the aquaglyceroporins, also allow the transport of glycerol, which is involved in the biosynthesis of triglycerides and the maintenance of fasting glucose levels. Aquaporin-7 (AQP7) is a glycerol channel mainly expressed in adipocytes. The deletion of AQP7 gene in mice leads to obesity and type 2 diabetes. AQP7 modulates adipocyte glycerol permeability thereby controlling triglyceride accumulation and fat cell size. Furthermore, the coordinated regulation of fat-specific AQP7 and liver-specific AQP9 may be key to determine glucose metabolism in insulin resistance.     

Arginine vasopressin in the caudate nucleus plays an antinociceptive role in the rat

Our previous work has shown that arginine vasopressin (AVP) regulates antinociception through brain nuclei rather than the spinal cord and peripheral organs. The present study investigated the nociceptive effect of AVP in the caudate nucleus (CdN) of the rat. Microinjection of AVP into the CdN increased pain threshold in a dose-dependent manner, while local administration of AVP-receptor antagonist-d(CH(2))(5)Tyr(Et)DAVP decreased pain threshold. Pain stimulation elevated AVP concentration in CdN perfuse liquid. CdN pretreatment with AVP-receptor antagonist completely reversed AVP's effect on pain threshold in the CdN. The data suggest that AVP in the CdN is involved in antinociception.     

Estrogenic activity of triterpene glycosides in yeast two-hybrid assay

Estrogenic potency of six triterpene glycosides, Holothurin A, Holotoxin A₁, Frondoside A, Cucumarioside A₂-2 and Cauloside C, that are natural products and semi-synthesized Ginsenoside-Rh₂, were examined with yeast two-hybrid system, including expressed genes of human estrogen receptor, hER, the co-activator TIF2 and lacZ as a reporter gene. Only Ginsenoside-Rh₂ exhibited significant moderate estrogenic activity in the concentration range of 10⁻⁷ to 10⁻⁶ M. Its effect was approximately 30% of the activity of 17β-estradiol applied at half-effective concentration. This indicates Ginsenosides-Rh₂ is a weak phytoestrogen. The sea cucumber triterpene glycosides, Holothurin A, Holotoxin A₁, Cucumarioside A₂-2 and Frondoside A, and plant glycoside Cauloside C had no appreciable estrogenic activity. Data obtained by yeast two-hybrid assay reflect structure–activity relationship between tested compounds and 17β-estradiol. Only Ginsenoside-Rh₂ has some similarity in chemical structure with 17β-estradiol that might explain affinity of this glycoside to the hER receptor.     

Dose-, time-, and tissue-dependent effects of 5-bromo-2′ -deoxyuridine on the in-vitro organogenesis of Arabidopsis thaliana

Vigorous organogenesis can be induced from hypocotyl and root explants of Arabidopsis thaliana using a two-step culture procedure consisting of preculture on callus-inducing medium (CIM) and subsequent culture on shoot-inducing medium (SIM) or root-inducing medium (RIM). With this culture system, we examined the influence of 5-bromo-2′-deoxyuridine (BrdU), a thymidine (dT) analogue, on plant organogenesis in vitro. Treatment with BrdU during SIM or RIM culture had negative effects on shoot and root redifferentiation over a broad range of concentrations. When explants were exposed to low concentrations of BrdU during preculture and then transferred onto BrdU-free SIM, shoot redifferentiation was accelerated significantly. At higher doses, BrdU treatment during the pre-culture inhibited shoot redifferentiation strongly in hypocotyl explants, but not in root explants. This suggests that a target of the BrdU action lies within the process of acquisition of cell proliferation competence specifically involved in hypocotyl dedifferentiation. These effects of BrdU were counteracted by the simultaneous addition of excess dT. BrdU-pretreated and untreated explants did not differ significantly in the phytohormone dependency of shoot redifferentiation. Our results provide a basis for future studies on plant organogenesis combining pharmacological analysis with BrdU as a probe and molecular genetics with Arabidopsis mutants.     

基于替代数据思想的复杂度归一化方法及其在心电信号分析中的应用

基于替代数据(Surrogate)思想的复杂度归一化方法,克服了一般复杂度对信号采样长度与采样频率的敏感性。文章对在生物医学信号复杂度分析中最有潜在应用价值的近似熵和C0复杂度进行了归一化。应用该方法可以有效地反映人体心脏某些病理状态之间的差别。同时,通过比较各种复杂度指标发现,C0复杂度和近似熵对采样长度的敏感性最弱,适用于短数据量的信号分析。     

Prediction of GPCR-G protein coupling specificity using features of sequences and biological functions

Understanding the coupling specificity between G protein-coupled receptors （GPCRs） and specific classes of G proteins is important for further elucidation of receptor functions within a cell. Increasing information on GPCR sequences and the G protein family would facilitate prediction of the coupling properties of GPCRs. In this study, we describe a novel approach for predicting the coupling specificity between GPCRs and G proteins. This method uses not only GPCR sequences but also the functional knowledge generated by natural language processing, and can achieve 92.2% prediction accuracy by using the C4.5 algorithm. Furthermore, rules related to GPCR-G protein coupling are generated. The combination of sequence analysis and text mining improves the prediction accuracy for GPCR-G protein coupling specificity, and also provides clues for understanding GPCR signaling.     

Various tolerances to arsenic trioxide between human cortical neurons and leukemic cells

Arsenic trioxide (As2O3) is very effective for treatment of acute promyelocytic leukaemia (APL) but little can pass through the blood-brain-barrier (BBB),which limits its use in the prevention and treatment of central nervous system leukaemia (CNSL). Before creating a non-invasive method to help As2O3 ’s access,the safe and effective therapeutic concentration of As2O3 in the CNS ought to be known. The changes of apoptosis biomarkers,[Ca2 ]i and PKC activity of both leukaemia cells and human cortical neurons,were monitored before and after being treated with As2O3 in vitro with laser confocal microscopy and Western blot. NSE concentration,the neuron invasive biomarker,was monitored by enzyme immunoassay (NSE-EIA). This study revealed that cortical neuron was more tolerable to As2O3 compared to NB4. 1.0 μmol / L As2O3 showed little influence on cortical neuron but effectively promoted apoptosis and induced differentiation of NB4.     

Identification of olfactory receptor neurons in Uraba lugens (Lepidoptera: Nolidae) and its implications for host range

Phytophagous insects detect volatile compounds produced by host and non-host plants, using species-specific sets of olfactory receptor neurons (ORNs). To investigate the relationship between the range of host plants and the profile of ORNs, single sensillum recordings were carried out to identify ORNs and corresponding active compounds in female Uraba lugens (Lepidoptera: Nolidae), an oligophagous eucalypt feeder. Based on the response profiles to 39 plant volatile compounds, 13 classes of sensilla containing 40 classes of ORNs were identified in female U. lugens. More than 95% (163 out of 171) of these sensilla contained 16 classes of ORNs with narrow response spectra, and 62.6% (107 out of 171) 18 classes of ORNs with broad response spectra. Among the specialized ORNs, seven classes of ORNs exhibited high specificity to 1,8-cineole, (±)-citronellal, myrcene, (±)-linalool and (E)-β-caryophyllene, major volatiles produced by eucalypts, while nine other classes of ORNs showed highly specialized responses to green leaf volatiles, germacrene D, (E)-β-farnesene and geranyl acetate that are not produced by most eucalypts. We hypothesize that female U. lugens can recognize their host plants by detecting key host volatile compounds, using a set of ORNs tuned to host volatiles, and discriminate them from non-host plants using another set of ORNs specialized for non-host volatiles. The ORNs with broad response spectra may enhance the discrimination between host and non-host plants by adding moderately selective sensitivity. Based on our finding, it is suggested that phytophagous insects use the combinational input from both host-specific and non-host specific ORNs for locating their host plants, and the electrophysiological characterization of ORN profiles would be useful in predicting the range of host plants in phytophagous insects.     

真菌次级代谢产物11’-deoxyverticillin A（C42）通过降低自噬基因的表达抑制肝炎病毒（HBV）复制

C42属于epipolythiodioxopiperazines（ETPs）二酮呱嗪类化合物,具有多种生物学活性,包括抑制病毒复制;不过其对hepatitis B virus（HBV）复制的影响及机理鲜有报道。自噬是广泛存在于真核细胞、通过溶酶体降解长半衰期蛋白的现象,参与多种生理、病理过程。有研究发现自噬对HBV的复制至关重要。C42是否通过改变自噬来影响此病毒的复制目前还未见报道。在该研究中,我们发现表达HBV基因组的HepG2.215细胞较原始的HepG2细胞,自噬体明显增加并伴随着Akt磷酸化的增高。C42可以降低自噬基因LC3-II和p62的水平,同时会影响Akt信号通路。氯喹是一种自噬抑制剂,它的存在可以抑制C42导致的LC3-II降低,表明C42可以引起该细胞的自噬。敲降自噬基因和抑制Akt磷酸化均可以减少HBV-X蛋白表达。而利用氯喹抑制自噬体与溶酶体的融合却提高了HBV-X蛋白水平。由于HBV-X对该病毒的复制至关重要,因此,我们认为,C42通过自噬和Akt信号通路来抑制HBV的复制。     

不同林龄油松(Pinus tabulaeformis)人工林植物、凋落物与土壤C、N、P化学计量特征

在陕西省北部延安市境内子午岭林区,采用时空互代的方法选取9、23、33、47年生油松(Pinus tabuliformis)人工林为研究对象,比较油松不同器官(叶、枝、干、根)、凋落物及土壤C、N、P含量及其比值的差异,探讨它们随林龄的变化及其相互间的关系,以期为油松人工林的生产、改善和林木生长环境的调节提供参考。结果表明:除根中C含量在林龄间差异不显著外,其它器官C、N、P含量及其比值在林龄间均差异显著且随林龄增加变化趋势不尽相同。9、23、33、47年生油松林C、N、P含量及N∶P比值均在叶中最高;C∶N比值均在干中最高,根中次之;C∶P比值均在干中最高,其它器官大小次序不一。除33年生油松林叶中N∶P比值大于14外,其它各器官各林龄N∶P比值均小于14,且N∶P比值随林龄先增加后减少,故可判断油松在该区域受N限制较为严重,且随林龄的增加受N限制的情况有所缓解。不同林龄土壤和凋落物C、N、P含量及其比值差异显著,且后者均大于前者。土壤与凋落物C、P含量及C∶N、C∶P、N∶P比值随林龄增加变化趋势完全一致,表明土壤与凋落物之间有着密切的关系。叶片与凋落物N、P含量及C∶N、C∶P、N∶P比值之间显著相关,表明凋落物的养分承自植物叶片,二者之间关系紧密;植物和土壤的C、N、P含量之间均不存在显著相关性,说明土壤C、N、P供应量对乔木叶片C、N、P含量影响不大。