Lipolysis in homogenates of adipose tissue: an inhibitor found in fat from obese rats

The presence of a lipidbound inhibitor in adipose tissue of rats with hypothalamic obesity may explain the failure of the tissue to release fatty acids on epinephrine stinmulation. Aqueous extracts of tissue from obese animals showed no deficiency of lipase activity, but when whole homogenates of epididymal fat from lean and obese animals were mixed, 25 percent tissue from obese animals reduced by 73 percent the release expected from tissue of lean controls.     

妊娠期背膘变化对繁殖性能的影响

母猪的繁殖性能是猪场主要生产指标,而母猪的背膘厚与繁殖性能存在较强的相关性。为研究母猪妊娠期不同阶段调控背膘厚对母猪的繁殖性能的影响,以温氏种猪公司新法系经产大白母猪为研究对象,测定妊娠期各阶段母猪背膘厚及繁殖性能。结果表明：妊娠前期和中期背膘厚调控范围为-2~3 mm母猪繁殖性能最佳;妊娠后期背膘厚调控范围为-2~0 mm母猪繁殖性能最佳。妊娠期母猪背膘厚保持在合适的范围,可以提高其繁殖性能,增加猪场效益。     

Magnetic resonance spectroscopy identifies neural progenitor cells in the live human brain

The identification of neural stem and progenitor cells (NPCs) by in vivo brain imaging could have important implications for diagnostic, prognostic, and therapeutic purposes. We describe a metabolic biomarker for the detection and quantification of NPCs in the human brain in vivo. We used proton nuclear magnetic resonance spectroscopy to identify and characterize a biomarker in which NPCs are enriched and demonstrated its use as a reference for monitoring neurogenesis. To detect low concentrations of NPCs in vivo, we developed a signal processing method that enabled the use of magnetic resonance spectroscopy for the analysis of the NPC biomarker in both the rodent brain and the hippocampus of live humans. Our findings thus open the possibility of investigating the role of NPCs and neurogenesis in a wide variety of human brain disorders.     

从巨噬细胞极化角度分析不同油脂饮食对小鼠腹股沟皮下脂肪组织沉积的影响

为分析两种脂肪供能条件下3种不同油脂饮食对小鼠腹股沟皮下脂肪沉积及其巨噬细胞分型的影响,90只C57BL/6J小鼠被随机分为6组,分别饲喂低脂猪油（Lar-10%）、低脂菜籽油（Rap-10%）、低脂橄榄油（Oli-10%）、高脂猪油（Lar-30%）、高脂菜籽油（Rap-30%）和高脂橄榄油（Oli-30%）,16周后解剖取腹股沟皮下脂肪组织,并对其进行苏木精-伊红染色,活性氧（Reactive oxygen species,ROS）含量检测,M1、M2型巨噬细胞标记物（CD11c和CD206）荧光双染,并通过ELISA检测其含量。结果表明：1）在低脂饮食条件下,三种油脂对小鼠腹股沟皮下脂肪组织重量、脂肪细胞横截面积、腹股沟皮下脂肪ROS含量均无显著影响（P>0.05）;2）随着脂肪供能水平的提高,小鼠腹股沟皮下脂肪沉积显著增加（P<0.05）,在高脂饮食条件下,Lar-30%组的小鼠腹股沟皮下脂肪组织重量显著高于Rap-30%和Oli-30%组（P<0.05）,并且相对于其他两组,Oli-30%组小鼠腹股沟皮下脂肪组织中ROS含量极显著降低（P<0.01）;...     

Dual origin of tissue-specific progenitor cells in Drosophila tracheal remodeling

During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells, tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. Clonal analysis and fate mapping of single, identified cells show that tracheal system remodeling at metamorphosis involves a classical imaginal cell population and a population of differentiated, functional larval tracheal cells that reenter the cell cycle and regain developmental potency. In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling. Thus, Drosophila pupal/adult tissue progenitors can arise both by early allocation of multipotent cells and late return of differentiated cells to a multipotent state, even within a single tissue.     

Insulin insensitivity of large fat cells

Large insulin-insensitive adipocytes from adult rats have normal binding capacities and affinities for insulin. Diminished insulin-like responses to spermine and reduced rates of glucose oxidation are also evident in these cells. The results indicate that the defect responsible for this insulin-resistant state exists in a step subsequent to insulin binding, possibly in transmission of the insulin-receptor "signal" since insensitivity occurs under conditions where glucose transport and oxidative processes are not apparently impaired.     

Insulin receptor of fat cells in insulin-resistant metabolic states

A diminished response to insulin is exhibited by isolated fat cells obtained from rats that have been either starved, or treated with prednisone, or made diabetic by administration of streptozotocin. This decrease in response is not accompanied by changes in the quantity of insulin receptor of these cells or in the affinity of these receptors for insulin. Similarly, the decreased responsiveness to insulin of fat cells obtained from certain species (hamster, rabbit, mouse, guinea pig) is not explainable in terms of alterations of the insulin receptor.     

Parasympathetic innervation maintains epithelial progenitor cells during salivary organogenesis

The maintenance of a progenitor cell population as a reservoir of undifferentiated cells is required for organ development and regeneration. However, the mechanisms by which epithelial progenitor cells are maintained during organogenesis are poorly understood. We report that removal of the parasympathetic ganglion in mouse explant organ culture decreased the number and morphogenesis of keratin 5-positive epithelial progenitor cells. These effects were rescued with an acetylcholine analog. We demonstrate that acetylcholine signaling, via the muscarinic M1 receptor and epidermal growth factor receptor, increased epithelial morphogenesis and proliferation of the keratin 5-positive progenitor cells. Parasympathetic innervation maintained the epithelial progenitor cell population in an undifferentiated state, which was required for organogenesis. This mechanism for epithelial progenitor cell maintenance may be targeted for organ repair or regeneration.     

Retroviral vector-mediated gene transfer into human hematopoietic progenitor cells

The transfer of the human gene for hypoxanthine phosphoribosyltransferase (HPRT) into human bone marrow cells was accomplished by use of a retroviral vector. The cells were infected in vitro with a replication-incompetent murine retroviral vector that carried and expressed a mutant HPRT complementary DNA. The infected cells were superinfected with a helper virus and maintained in long-term culture. The production of progeny HPRT virus by the bone marrow cells was demonstrated with a colony formation assay on cultured HPRT-deficient, ouabain-resistant murine fibroblasts. Hematopoietic progenitor cells able to form colonies of granulocytes or macrophages (or both) in semisolid medium in the presence of colony stimulating factor were present in the nonadherent cell population. Colony forming units cloned in agar and subsequently cultured in liquid medium produced progeny HPRT virus, indicating infection of this class of hematopoietic progenitor cell.     

绵羊白细胞内的慢病毒cDNA GAG基因PCR检测

采用PCR技术,以绵羊外周血白细胞基因组为模板,扩增绵羊慢病毒gag基因全长,将该基因克隆到pBS-T载体上,将重组子转入感受态细胞DH5α,用IPTG/X-gel筛选阳性菌落,通过菌落PCR,酶切初步鉴定后测序,所测序列与Genbank中的基因序列进行比对,所克隆序列与慢病毒gag基因序列一致。实验表明:在绵羊的白细胞慢病毒的cDNAgag基因的PCR检测是可行的。     

Erythropoietin retards DNA breakdown and prevents programmed death in erythroid progenitor cells

The mechanism by which erythropoietin controls mammalian erythrocyte production is unknown. Labeling experiments in vitro with [3H]thymidine demonstrated DNA cleavage in erythroid progenitor cells that was accompanied by DNA repair and synthesis. Erythropoietin reduced DNA cleavage by a factor of 2.6. In the absence of erythropoietin, erythroid progenitor cells accumulated DNA cleavage fragments characteristic of those found in programmed cell death (apoptosis) by 2 to 4 hours and began dying by 16 hours. In the presence of erythropoietin, the progenitor cells survived and differentiated into reticulocytes. Thus, apoptosis is a major component of normal erythropoiesis, and erythropoietin controls erythrocyte production by retarding DNA breakdown and preventing apoptosis in erythroid progenitor cells.     

Selective differentiation of neural progenitor cells by high-epitope density nanofibers

Neural progenitor cells were encapsulated in vitro within a three-dimensional network of nanofibers formed by self-assembly of peptide amphiphile molecules. The self-assembly is triggered by mixing cell suspensions in media with dilute aqueous solutions of the molecules, and cells survive the growth of the nanofibers around them. These nanofibers were designed to present to cells the neurite-promoting laminin epitope IKVAV at nearly van der Waals density. Relative to laminin or soluble peptide, the artificial nanofiber scaffold induced very rapid differentiation of cells into neurons, while discouraging the development of astrocytes. This rapid selective differentiation is linked to the amplification of bioactive epitope presentation to cells by the nanofibers.     

Insulin-stimulated glucose uptake by subcellular particles from adipose tissue cells

Microsomal particles prepared from isolated rat adipose cells take up D-glucose more rapidly than L-glucose. The rate of D-glucose uptake, but not that of L-glucose, is stimulated by incubation of the intact cells with insulin at concentrations as low as 10 microunits per milliliter before disruption and preparation of the microsomes.     

Brown adipose cells: spontaneous mobilization of endogenously synthesized lipid

Isolated brown adipose cell devoid of a basement membrane, readily synthesized a variety of lipids from radioctive acetate, a reactionaugmented by glucose and insulin. A large proportion of the newly formed fatty acids passed into the incubation medium. In intact brown adipose slices and isolated white adipose cells, most of the synthesized lipid was retained as glyceride esters. The date suggest that the rapid turnover of endogenously synthesized lipid in brown adipose cells is almost totally obscured in studies with intact tissue slices because of interstitial barriers to the egress of fatty acid.     

Therapy-induced acute recruitment of circulating endothelial progenitor cells to tumors

The contribution of bone marrow-derived circulating endothelial progenitor cells (CEPs) to tumor angiogenesis has been controversial, primarily because of their low numbers in blood vessels of untreated tumors. We show that treatment of tumor-bearing mice with vascular disrupting agents (VDAs) leads to an acute mobilization of CEPs, which home to the viable tumor rim that characteristically remains after such therapy. Disruption of this CEP spike by antiangiogenic drugs or by genetic manipulation resulted in marked reductions in tumor rim size and blood flow as well as enhanced VDA antitumor activity. These findings also provide a mechanistic rationale for the enhanced efficacy of VDAs when combined with antiangiogenic drugs.     

Comment on "Magnetic resonance spectroscopy identifies neural progenitor cells in the live human brain"

Manganas et al. (Reports, 9 November 2007, p. 980) used nuclear magnetic resonance spectroscopy to identify a biomarker of neural progenitor cells. However, their analysis relies on spectral processing methods that are known to be problematic. Absent detection using alternate methods of spectrum analysis or controls to quantify the false discovery rate, their conclusions may be premature.     

A clonogenic bone marrow progenitor specific for macrophages and dendritic cells

Macrophages and dendritic cells (DCs) are crucial for immune and inflammatory responses and belong to a network of cells that has been termed the mononuclear phagocyte system (MPS). However, the origin and lineage of these cells remain poorly understood. Here, we describe the isolation and clonal analysis of a mouse bone marrow progenitor that is specific for monocytes, several macrophage subsets, and resident spleen DCs in vivo. It was also possible to recapitulate this differentiation in vitro by using treatment with the cytokines macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. Thus, macrophages and DCs appear to renew from a common progenitor, providing a cellular and molecular basis for the concept of the MPS.     

玉米皮替代玉米粉对湘东黑山羊内脏脂肪组织脂肪代谢的影响

[目的]明确玉米皮替代玉米粉对山羊脂肪代谢的影响,为玉米皮在反刍动物养殖生产中的合理应用提供参考依据.[方法]选择10月龄左右、体重(17.50±2.67 kg/只)相近的健康雄性湘东黑山羊20只,随机分成2组[玉米粉组(CM组)和玉米皮(CG组)],每组10只.山羊日粮精粗比为75:25,CM组饲喂基础饲粮,CG组饲喂以玉米皮完全替代玉米粉的试验饲粮.饲喂60 d后进行屠宰,迅速采集网膜脂肪组织(简称网膜脂)、肠系膜脂肪组织(简称系膜脂)和肾周脂肪组织(简称肾周脂),通过Agilent 7890A气相色谱仪和实时荧光定量PCR检测其脂肪酸组成及脂肪代谢相关基因的表达情况.[结果]与CM组相比,CG组山羊网膜脂中的豆蔻酸(C14:0)、十七烷酸(C17:0)、硬脂酸(C18:0)、反式油酸(C18:1n9t)及花生酸(C20:0)含量显著(P<0.05,下同)或极显著(P<0.01,下同)上升;系膜脂中的十七烷酸和α-亚麻酸(C18:3n3)含量显著上升,肉豆蔻酸含量显著下降;而肾周脂的脂肪酸组成无显著变化(P>0.05,下同).山羊内脏脂肪的饱和脂肪酸总含量、单不饱和脂肪酸总含量及多不饱和脂肪酸总含量在CG组与CM组间均无显著差异.在脂肪代谢相关基因表达方面,与CM组相比,CG组山羊网膜脂中的乙酰辅酶A羧化酶基因(ACC)极显著上调表达;系膜脂中的脂肪酸去饱和酶1基因(FADS1)极显著下调表达,锌指蛋白类转录因子2(KLF2)、锌指蛋白类转录因子4(KLF4)、胆固醇调节元件结合蛋白1基因(SREBP1)则显著上调表达;肾周脂中的SREBP1基因极显著下调表达.[结论]以玉米皮替代玉米粉会不同程度地影响湘东黑山羊内脏脂肪组织中某些脂肪酸含量及脂肪代谢相关基因表达,但对内脏脂肪组织的饱和脂肪酸、单不饱和脂肪酸及多不饱和脂肪酸含量均无显著影响,即以玉米皮代替玉米粉对山羊内脏脂肪组织脂肪酸组成的总体影响较小,可在实际生产中推广应用.