TNF-alpha and adipocyte biology

Dyslipidemia and insulin resistance are commonly associated with catabolic or lipodystrophic conditions (such as cancer and sepsis) and with pathological states of nutritional overload (such as obesity-related type 2 diabetes). Two common features of these metabolic disorders are adipose tissue dysfunction and elevated levels of tumour necrosis factor-alpha (TNF-alpha). Herein, we review the multiple actions of this pro-inflammatory adipokine on adipose tissue biology. These include inhibition of carbohydrate metabolism, lipogenesis, adipogenesis and thermogenesis and stimulation of lipolysis. TNF-alpha can also impact the endocrine functions of adipose tissue. Taken together, TNF-alpha contributes to metabolic dysregulation by impairing both adipose tissue function and its ability to store excess fuel. The molecular mechanisms that underlie these actions are discussed.     

Cooperation between BAT and WAT of rats in thermogenesis in response to cold, and the mechanism of glycogen accumulation in BAT during reacclimation

Rats were exposed to cold and then reacclimated at neutral temperature. Changes related to fatty acid and glucose metabolism in brown and white adipose tissues (BAT and WAT) and in muscle were then examined. Of the many proteins involved in the metabolic response, two lipogenic enzymes, acetyl-coenzyme A carboxylase (ACC) and ATP-citrate lyase, were found to play a pervasive role and studied in detail. Expression of the total and phosphorylated forms of both lipogenic enzymes in response to cold increased in BAT but decreased in WAT. Importantly, in BAT, only the phosphorylation of the ACC1 isoenzyme was enhanced, whereas that of ACC2 remained unchanged. The activities of these enzymes and the in vivo rate of FFA synthesis together suggested that WAT supplies BAT with FFA and glucose by decreasing its own synthetic activity. Furthermore, cold increased the glucose uptake of BAT by stimulating the expression of components of the insulin signaling cascade, as observed by the enhanced expression and phosphorylation of Akt and GSK-3. In muscle, these changes were observed only during reacclimation, when serum insulin also increased. Such changes may be responsible for the extreme glycogen accumulation in the BAT of rats reacclimated from cold.     

A novel photoactive GAF domain of cyanobacteriochrome AnPixJ that shows reversible green/red photoconversion

We report the discovery of a novel cyanobacteriochrome, the green/red photoreceptor AnPixJ (All1069), isolated from the heterocyst-forming cyanobacterium Anabaena (Nostoc) sp. PCC 7120. Cyanobacteriochromes are a recently emerging tetrapyrrole-based photoreceptor superfamily that are distantly related to the conventional red/far-red photoreceptor phytochromes (Phys). The chromophore-binding domains of AnPixJ produced in cyanobacterial and Escherichia coli cells both showed a reversible and full photoconversion between a green-absorbing form (λ_max = 543 nm) and a red-absorbing form (λ_max = 648 nm). Denaturation analysis revealed that the green-absorbing form and the red-absorbing form covalently ligated phycocyanobilin with E-configuration and Z-configuration at the C15C16 double bond, respectively. Time-resolved spectral analysis showed the formation of the first intermediate state peaking at 680 nm from the dark-stable red-absorbing form. This step resembles the first photoconversion step from the red-absorbing form to the red-shifted lumi-R intermediate state of the Phys. These results suggest that the Pr of AnPixJ is almost equivalent to that of the Phys and starts a primary photoreaction with Z-to-E isomerization in a mechanism similar to that in the Phys, but is finally photoconverted to the unique green-absorbing form.     

Brain metabolism in adult chronic hydrocephalus

Normal pressure hydrocephalus (NPH) is the most frequent form of chronic hydrocephalus in adults. NPH remains underdiagnosed although between 5% and 10% of all demented patients may suffer from this disorder. As dementia is an increasing demographic problem, treatable forms such as in NPH have become a central issue in neurology. Despite the traditional perception of hydrocephalus being a disorder of disturbed CSF dynamics, in NPH metabolic impairment seems at least as important. So far, the only valid animal model of NPH is chronic adult kaolin hydrocephalus. In this model, opening of alternative CSF outflow pathways leads to normal or near-normal intracranial pressure and CSF outflow resistance. Yet, various metabolic disturbances cause ongoing ventricular enlargement and characteristic symptoms including cognitive decline and gait ataxia. Delayed hippocampal neuronal death, accumulation of beta-amyloid and disturbed cholinergic neurotransmission may contribute to memory dysfunction. Compromised periventricular blood flow, decreased dopamine levels in the substantia nigra and damaged striatal GABAergic interneurons may reflect basal ganglia symptoms. At least in human hydrocephalus cerebrovascular co-morbidity of the white matter plays an important role as well. It seems that in hydrocephalus from a certain 'point of no return' metabolic impairment becomes decoupled from CSF dynamics and, at least partly, self-sustained. This is probably the reason why despite restored CSF circulation by shunting many patients with chronic hydrocephalus still suffer from severe neurological deficits. The present paper offers a comprehensive review of the experimental and clinical data suggesting metabolic disturbances in chronic hydrocephalus.     

利用宿主范围扩大的杂交病毒HyNPV在家蚕中表达对虾白斑综合症病毒VP19基因

对虾白斑综合症其病原是对虾白斑综合症病毒（White spot syndrome virus,简称WSSV）。 VP19是 WSSV的一个囊膜蛋白,HyNPV（Hybrid of AcNPV and BmNPV,简称HyNPV）是BmNPV和AcNPV通过基因重组后得到的一个具有BmNPV和AcNPV双重优点的新型杂交病毒,在克隆了VP19基因的基础上,成功构建了重组转移载体pBlueBicHisC-vp19和重组杆状病毒 HyNPV-VP19。用重组病毒注射接种5龄起蚕,经SDS-PAGE 和Western blotting分析,结果表明,WSSV-VP19基因在家蚕体内得到了表达,特异性条带大小与预计的基本一致,约为21kD。     

Screening for Ligninolytic Enzyme Production by Diverse Fungi from Tunisia

Summary This work represents the first report on the ability of autochthonous fungi from Tunisia to produce ligninolytic enzymes. Three hundred and fifteen fungal strains were isolated from different Tunisian biotopes. These fungal strains were firstly screened on solid media containing Poly R-478 or ABTS as indicator compounds that enabled the detection of lignin-modifying enzymes as specific color reactions. Of the 315 tested strains, 49 exhibited significant ABTS-oxidation activity expressed within the first week of incubation and only 18 strains decolorized the Poly R-478. Liquid cultivations and laccase, manganese peroxidase and lignin peroxidase activity assays of positive strains confirmed that eight efficient enzyme producers were found in the screening. These strains were attributed to the most closely related species using PCR amplification and sequencing of the internal transcribed spacer ‘ITS’ regions of the ribosomal DNA. The identification results showed fungal genera such as Oxyporus, Stereum and Trichoderma which have been only rarely reported as ligninolytic enzyme producers in the literature. Culture conditions and medium composition were optimized for the laccase producer Trametes trogii CTM 10156. This optimization resulted in high laccase production, 367 times more than in non-optimized conditions and which reached 110 U ml^-1 within 15 days of incubation.     

Formation of melanin-based wing patterns is influenced by condition and immune challenge in Pieris brassicae

According to life‐history theory, trade‐offs emerge because organisms possess a limited amount of resources that they have to allocate between different bodily functions. Here, we tested whether there is a trade‐off between melanin‐based immune response and dark melanized wing patterning in the large white butterfly, Pieris brassicae L. (Lepidoptera: Pieridae), by activating the immune system of pupae and measuring the wing pigmentation of freshly emerged adults. In contrast to expectations, we did not find any negative associations between immune challenge and wing patterning. Furthermore, implanted and punctured male pupae tended to have larger and darker forewing tips as adults compared to controls. Both in females and males, different wing spots were affected by condition‐reflecting traits (e.g., pupal mass, brood), which suggest that formation of wing patterns may be a condition‐dependent process and/or heritable.     

三江白猪线粒体DNA的多态性

采用22种限制性内切酶分析了三江白猪mtDNA多态性。在60头个体中检出30种限制性态型,归结为7种基因单倍型;其间的差异来自少数限制性位点的突变。单倍型间平均遗传距离为0．35％,群体遗传多态程度为0．044％。三江白猪遗传多样性非常贫乏,说明三江白猪与地方种猪起源于一个共同祖先,在品种形成早期受到创立者效应的制约。     

FLIM on a wide field fluorescence microscope

Summary FLIM (Fluorescence Lifetime Imaging Microscopy) is a new tool to detect interaction between proteins. The proteins under investigation are fused with fluorescent donor and acceptor molecules. Interaction between the two proteins is accompanied by direct energy transfer from donor to acceptor (FRET), resulting in a shorter lifetime of the fluorescence emitted by the donor molecule. This change in lifetime is detected by FLIM. Fluorescence lifetime imaging can now be done on a widefield fluorescence microscope by using an attachment that is easy to install and simple to operate. The new LIFA attachment is equipped to use different excitation sources. High brightness modulated LEDs as well as lasers modulated by an Accousto Optical Modulator can be used as excitation light source. A modulated image intensifier with digital camera is used as a detector. Power supplies and signal generator are integrated in one control unit that is connected to the light source, detector and computer. All parameters for image acquisition, processing and viewing are easy accessible in the user interface of the software package that uses a modular structure. Lifetime images showing FRET in MCF7 cells with ErbB1-GFP as donor and Py72/Cy3 as acceptor that were taken at EMBL, Heidelberg are shown.