Determinants of food intake in obesity

Obese human subjects who were offered three sandwiches ate more than normal subjects. When only one sandwich was offered and additional sandwiches were available but out of sight, the obese subjects ate less than normal subjects. This resuclt is discussed in terms of the types of cues that motivate eating for obese versus normal individuals.     

Regulation of food intake and obesity

This is not the place to consider the medical significance of obesity in terms of conditions such as heart disease and hypertension, diabetes, and arthritis. These very complex interrelationships have been dealt with elsewhere (69). We hope that enough evidence has been presented to demonstrate that energy balance is normally maintained by a precise and reliable physiologic mechanism, and that the energy surplus represented by obesity may reflect direct failure of this mechanism or some combination from a variety of neurological, endocrine, enzymatic, and psychological disorders. Environmental conditions as well as genetic and traumatic factors may contribute to the development of obesity. If increasing mechanization brings tus below the level of energy expenditure at which food intake is properly regulated, appropriate habits of exercise will have to be established and maintained.     

Hypothalamic mTOR signaling regulates food intake

The mammalian Target of Rapamycin (mTOR) protein is a serine-threonine kinase that regulates cell-cycle progression and growth by sensing changes in energy status. We demonstrated that mTOR signaling plays a role in the brain mechanisms that respond to nutrient availability, regulating energy balance. In the rat, mTOR signaling is controlled by energy status in specific regions of the hypothalamus and colocalizes with neuropeptide Y and proopiomelanocortin neurons in the arcuate nucleus. Central administration of leucine increases hypothalamic mTOR signaling and decreases food intake and body weight. The hormone leptin increases hypothalamic mTOR activity, and the inhibition of mTOR signaling blunts leptin's anorectic effect. Thus, mTOR is a cellular fuel sensor whose hypothalamic activity is directly tied to the regulation of energy intake.     

Neural correlates of food and water intake in the rat

Adrenergic and cholinergic stimulation of several interrelated limbic and diencephalic areas causes the animal to eat and drink, respectively. The brain areas involved may be organized in terms of "Papez circuit" and, more generally, " Nauta circuit" neuroanatomy. However, it is proposed that separate synaptic nets, one for the control of hunger and one for the control of thirst, are deployed throughout the brain at all levels, including neocortical.     

Nicotine decreases food intake through activation of POMC neurons

Smoking decreases appetite, and smokers often report that they smoke to control their weight. Understanding the neurobiological mechanisms underlying the anorexic effects of smoking would facilitate the development of novel treatments to help with smoking cessation and to prevent or treat obesity. By using a combination of pharmacological, molecular genetic, electrophysiological, and feeding studies, we found that activation of hypothalamic α3β4 nicotinic acetylcholine receptors leads to activation of pro-opiomelanocortin (POMC) neurons. POMC neurons and subsequent activation of melanocortin 4 receptors were critical for nicotinic-induced decreases in food intake in mice. This study demonstrates that nicotine decreases food intake and body weight by influencing the hypothalamic melanocortin system and identifies critical molecular and synaptic mechanisms involved in nicotine-induced decreases in appetite.     

CMLs参与调控植物花粉授粉竞争的作用

目的在显花植物生殖过程中花粉萌发和花粉管生长起着至关重要的作用,这一过程受许多因素的影响,其中钙调素类似蛋白（calmodulin-like proteins,CMLs）通过直接或间接的作用机制调控花粉萌发及花粉管生长。然而,迄今人们对CMLs的功能研究尚少。本文旨在初步了解CMLs蛋白在花粉竞争优势中的作用,为深入探究CMLs蛋白在植物花粉竞争优势中的分子机制奠定理论基础。方法本文主要通过对参与调控花粉萌发以及花粉管生长过程的CMLs蛋白的结构、表达水平、细胞定位及其作用机理的归纳,结合不同植物中出现的花粉竞争现象,综合分析并总结国内外相关研究结果。结果CMLs蛋白约有4个保守的EF手性结构域,当CMLs蛋白结合Ca2+时,其构象发生变化,增强与下游受体蛋白的结合能力,并启动Ca2+依赖的级联信号放大效应,引起花粉管中Ca2+的浓度变化,影响从萌发孔到花粉管顶端Ca2+浓度梯度的形成,从而调控花粉管的正常生长。CMLs蛋白的表达还可以影响Mg2+、NO等离子的浓度变化,影响Ca2+与EF手性结构域的结合及花粉管生长的导向。不同CMLs蛋白具有不同生理功能,其中参与花粉萌发及花粉管生长的CMLs蛋白主要在植物花器官中表达;部分显花植物在受精过程中,不同倍性花粉之间可能由于基因组大小或者营养物质含量的差异,导致萌发率及生长速率的不同。结论CMLs蛋白可能通过在不同倍性花粉中的差异表达,影响花粉在体内萌发的进程,使其在某一时期表现出竞争优势。      

表油菜素内酯对葡萄果实成熟的调控及与脱落酸的关系

【目的】研究表油菜素内酯(Epibrassinolide)对葡萄成熟的调控作用及其在葡萄成熟过程中与脱落酸(ABA)的关系,为表油菜素内酯在葡萄上的研究与应用提供理论依据。【方法】以欧亚种酿酒葡萄(Vitis vinifera L.)品种赤霞珠(Cabernet Sauvignon)为供试材料,试验共设4个处理:(1)0.4mg/L EBR(24-Epibrassinolide,24-表油菜素内酯);(2)0.4mg/L EBR+20mg/L Flu(氟啶酮)或0.4mg/L EBR+15mg/L NDGA(去甲二氢愈创木酸);(3)20mg/L Flu或15mg/L NDGA;(4)喷清水对照(CK)。在葡萄果实成熟过程中(转色10%,转色50%,转色100%及成熟),研究EBR处理对葡萄果实成熟及酚类物质含量的影响,分析EBR在调控葡萄成熟过程中与ABA的关系。【结果】与对照相比,EBR处理可显著提高成熟葡萄果实还原糖以及浆果果皮中总酚、单宁和花色苷含量,降低其可滴定酸含量,其果实还原糖含量以及果皮中总酚、单宁和花色苷含量分别提高了3.3%,6.4%,9.5%和18.5%,可滴定酸含量下降了5.9%;EBR+Flu处理和EBR+NDGA处理可以显著提高成熟葡萄的还原糖、总酚和花色苷含量,降低可滴定酸含量,其还原糖、总酚和花色苷含量分别提高了5.3%,11.2%,5%以及16.5%,12.5%,21%,可滴定酸含量下降了12.7%和19.5%,对单宁含量的影响与EBR处理无明显差异;Flu和NDGA处理葡萄果实的还原糖含量也显著高于对照。【结论】EBR处理可以促进葡萄果实的成熟以及总花色苷的合成,使用ABA生物合成抑制剂时,EBR对于葡萄成熟和花色苷合成的促进作用更为显著。     

Reduced food intake and body weight in mice treated with fatty acid synthase inhibitors

With the escalation of obesity-related disease, there is great interest in defining the mechanisms that control appetite and body weight. We have identified a link between anabolic energy metabolism and appetite control. Both systemic and intracerebroventricular treatment of mice with fatty acid synthase (FAS) inhibitors (cerulenin and a synthetic compound C75) led to inhibition of feeding and dramatic weight loss. C75 inhibited expression of the prophagic signal neuropeptide Y in the hypothalamus and acted in a leptin-independent manner that appears to be mediated by malonyl-coenzyme A. Thus, FAS may represent an important link in feeding regulation and may be a potential therapeutic target.     

盐度对口虾蛄假溞状幼体存活和摄食的影响

在实验室条件下,观测了盐度对口虾蛄Oratosquilla oratoria Z9～Z11期假溞状幼体存活和摄食的影响.设置盐度骤变和渐变两组试验,骤变试验以27为基础盐度,将假溞状幼体直接放入盐度为51、48、45、42、39、36、33、30、24、21、18、15、12、9的海水中;渐变试验盐度分别从24和33开始,每隔12h降低(低盐渐变)和升高(高盐渐变)一次盐度值,变化幅度为1,直至口虾蛄假溞状幼体全部死亡.以体长为5.19～8.91 mm(平均体质量为0.058 g)的鲜活糠虾作为饵料.试验结果表明:当盐度骤变到18～36时,口虾蛄假溞状幼体比较适应,24h时成活率在77.8％以上;盐度骤变情况下,24h半致死盐度为15.94和41.13;假溞状幼体适应骤变盐度的低盐度和高盐度极限分别为12和48,适应渐变盐度的低盐度和高盐度极限分别为6和54;当盐度低于15或高于45时,口虾蛄假溞状幼体基本不摄食,盐度为27、30和33时,假溞状幼体的摄食量明显高于其它盐度组.综合考虑成活率和摄食两方面的因素,培育口虾蛄Z9～Z11期假溞状幼体的适宜盐度为27 ～33.     

盐度对口虾蛄假溞状幼体存活和摄食的影响

在实验室条件下,观测了盐度对口虾蛄Oratosquilla oratoria Z9～Z11期假溞状幼体存活和摄食的影响。设置盐度骤变和渐变两组试验,骤变试验以27为基础盐度,将假溞状幼体直接放入盐度为51、48、45、42、39、36、33、30、24、21、18、15、12、9的海水中;渐变试验盐度分别从24和33开始,每隔12h降低(低盐渐变)和升高(高盐渐变)一次盐度值,变化幅度为1,直至口虾蛄假溞状幼体全部死亡。以体长为5.19～8.91 mm(平均体质量为0.058 g)的鲜活糠虾作为饵料。试验结果表明:当盐度骤变到18～36时,口虾蛄假溞状幼体比较适应,24 h时成活率在77.8%以上;盐度骤变情况下,24 h半致死盐度为15.94和41.13;假溞状幼体适应骤变盐度的低盐度和高盐度极限分别为12和48,适应渐变盐度的低盐度和高盐度极限分别为6和54;当盐度低于15或高于45时,口虾蛄假溞状幼体基本不摄食,盐度为27、30和33时,假溞状幼体的摄食量明显高于其它盐度组。综合考虑成活率和摄食两方面的因素,培育口虾蛄Z9～Z11期假溞状幼体的适宜盐度为27～33。     

玉米秸颗粒粕肉牛采食量及消化率的研究

用 12头西门塔尔杂种公牛 ,研究测定了肉牛对玉米秸颗粒粕及铡切玉米秸的采食量及消化率。测试结果表明 :肉牛对玉米秸颗粒粕具有相当好的适口性和采食量 ,对玉米秸颗粒粕消化率较铡切玉米秸虽有不同程度的降低 ,但其绝对消化吸收量较后者却有显著提高 ,因此 ,玉米秸颗粒粕在肉牛生产中应用是切实可行的     

Suppression of food intake with intragastric loading: relation to natural feeding cycle

Rats were infused through chronically implanted intragastric tubes with 100 percent of their normal total daily food intake. The infusion was given either continuously over 24 hours or divided into discrete meals programed to simulate the rats' natural eating pattern. The same diet was also available for consumption by mouth. In neither case did the animals completely stop eating. During slow infusions excessive consumption ranged from 30 to 50 percent. During simulated meal infusion of the same total quantity of diet, they compensated far better, overeating by only 2 to 18 percent. Periodic filling of the stomach between scheduled meals was no more effective than a continuous slow infusion. Therefore, factors related to the natural feeding cycle make a significant contribution to the effectiveness of food in maintaining satiety and controlling food intake.     

Anatomical connections between medial and lateral regions of the hypothalamus concerned with food intake

No anatomical connections have yet been demonstrated from the ventromedial ("satiety") to the lateral ("feeding") areas of the hypothalamus. Lesions were induced with goldthioglucose in mice in the ventromedial region, including the arcuate and ventromedial nuclei. With the Fink-Heimer stain for degenerating axons, fiber connections between these two areas were demonstrated.     

黄颡鱼仔稚鱼发育和摄食习性研究

在水温24～27℃时,黄颡鱼从仔鱼出膜至夏花历时30 d左右.仔稚鱼发育分为仔鱼前阶段、仔鱼阶段、稚鱼前阶段和稚鱼阶段,每个阶段又分为3个时期,共计12个时期.仔鱼的开口饵料主要为轮虫和小型枝角类.进入稚鱼阶段有2次食性转变,第1次由浮游动物转为底栖动物,第2次由底栖动物转为以动物性饵料为主的杂食性,并开始摄食人工精饲料.仔、稚鱼的摄食强度随个体生长而增强,并在稚鱼期有明显的昼夜摄食变化.     

中草药及其制剂对猪、鸡、羊疾病的免疫调节作用

对临床上常见的猪无名高热,动物的垂脱症及鸡的法氏囊等病症,笔者采用西药疗法与中药补中益气、提升免疫力的疗法进行对比试验。治疗猪无名高热346例,西药治愈率为18%,用中草药治愈率为88%,治疗猪的直肠脱、阴道脱及山羊的阴道脱20例,西药治疗效果不好,全都是采用中药及手术疗法而治愈;治疗鸡法氏囊病采用了对比试验,中草药治愈率为80%,且中药治愈后复发比例生产、生长性能优越于西药疗法。大量研究表明,中草药多糖作为许多中药的主要免疫活动性物质,不仅促进机体的细胞和体液免疫,并能促进免疫器官的发育,增强免疫功能。     

PYY组织表达及对翘嘴鳜的摄食调控

以肉食性鱼类翘嘴鳜(Siniperca chuatsi)为研究对象,对其肽YY(peptide YY,PYY)基因进行鉴定和分析,并通过中枢注射人工合成的鳜PYY多肽,研究PYY对翘嘴鳜摄食量的影响。氨基酸序列多重比对结果发现,sc-PYY与各个物种的氨基酸序列高度保守,鱼类中与狼鲈(Dicentrarchus labrax)、红鳍东方鲀(Takifugu rubripes)一致性较高;实时荧光定量PCR检测sc-PYY mRNA表达的组织分布,结果显示,sc-PYY mRNA在脑中表达量最高,在肠道、肌肉、眼睛中亦有较高的表达;翘嘴鳜中枢注射PYY后,摄食量在4 h相比于对照组(PBS)显著性下降。这表明PYY可能在减少鳜的食物摄入量中发挥着重要的作用。     

投喂模式对吉富罗非鱼摄食和生长的影响

以不同的投喂水平(100%、90%、80%、70%、60%、50%饱食投喂量)、每天投喂两次,不同的投喂频率(每天分别投喂1、2、3、4次)但日投喂总量(100%饱食投喂量)相同、分别投喂吉富罗非鱼幼鱼8周,分析不同投喂水平和投喂频率对吉富罗非鱼摄食生长性能、白肌生化组成及相关摄食因子mRNA转录水平的影响。结果表明,投喂水平较高或较低均会导致饲料系数和下丘脑NPY mRNA转录水平升高,特定生长率、饲料转化率和CCK1 mRNA转录水平降低,白肌生化成分中只有粗脂肪含量受投喂水平的影响达到显著性差异;投喂频率对罗非鱼生长各指标的影响均未达到显著性差异,但可观察到各指标的变化趋势,投喂频率过高或过低均会导致吉富罗非鱼的饲料转化率、特定生长率降低,饲料系数、下丘脑NPY mRNA转录水平升高,白肌各种生化成分含量随投喂频率的增加均有先升后降的趋势,全脑CCK1mRNA转录水平则逐渐降低,全脑Orexin mRNA转录水平逐渐升高。综合分析各种指标,吉富罗非鱼的最适投喂水平为80%饱食投喂量,每天投喂两次。     

3种鳜鱼生长与摄食量、胃蛋白酶活性和胃蛋白酶原基因表达相关分析

为了解不同种类鳜鱼生长差异的生理基础与机制,比较研究了鳜(Siniperca chuatsi)、斑鳜(Siniperca.scherzeri)和杂交鳜(斑鳜♀×鳜♂)幼鱼30 d内的生长速率与日摄食量、胃蛋白酶活性和胃蛋白酶原(PGA1、PGA2、PGC)基因相对表达量间的关系。结果表明,鳜、杂交鳜和斑鳜日增重率分别为(1.171±0.180)g/d、(1.019±0.104)g/d和(0.433±0.078)g/d,生长速率快慢次序是鳜杂交鳜斑鳜。鳜、杂交鳜和斑鳜平均日摄食量分别为(6.1±0.31)g/d、(5.26±0.33)g/d、(4.24±0.23)g/d。胃蛋白酶比活力最高部位是胃,实验前期,3种鳜鱼胃蛋白酶比活力差异不显著;后期,鳜、杂交鳜和斑鳜胃蛋白酶比活力分别为(347.8±13.3)U/g、(303.4±12.1)U/g和(272.1±10.9)U/g。胃蛋白酶原基因表达量随生长阶段缓慢增加,PGC∶PGA1∶PGA2基因相对表达量比例是1.1∶1.0∶0.7;鳜胃蛋白酶原基因的相对表达量均为最高,杂交鳜相对表达量略高于斑鳜(P0.05)。结果表明,3种鳜鱼的生长速率快慢与它们的摄食量大小之间呈正相关,摄食量大小与其消化能力间也具有相对应的关系。