Male tail streamer length does not predict apparent or genetic reproductive success in North American barn swallows Hirundo rustica erythrogaster

In the socially monogamous barn swallow, previous studies of individuals in the European subspecies Hirundo r. rustica have shown that a male's tail streamer length is under strong sexual selection and is positively associated with several measures of reproductive success, including a low probability of being cuckolded by other males. The prominence of these results has led to subsequent experimental and correlational investigations of individuals in the phenotypically divergent subspecies H. r. erythrogaster in North America, where it has been shown that male tail streamer length is not as strongly associated with reproductive success as in European populations. We examined relationships between male tail streamer length and patterns of: (1) social mate selection and reproductive success, and (2) extra-pair paternity in 265 progeny of 53 social fathers within a New York barn swallow population. Although tail streamers in this population were sexually dimorphic, male tail streamer length did not predict patterns of mate selection, seasonal reproductive success, or extra-pair paternity. Moreover, in contrast to the strong positive relationships between paternity and male streamer length in European populations, summarized in this paper, we found no positive relationship between a male's paternity of young in the nest he is attending and his tail streamer length in our study population in New York. Our results further corroborate recent suggestions that the function of sexual signals varies geographically in this species, although we await additional experimental analyses on streamer lengths to understand the maintenance of sexual dimorphism in this trait.     

Karyotype analysis in South American species of Myrtaceae

In Myrtaceae (Myrteae), the diploid chromosome number 2 n  = 2 x  = 22 is the most common, although variations of ploidy level occur, with some triploid (2 n  = 3 x  = 33) and tetraploid (2 n  = 4 x  = 44) records. Karyotype details in this group are scarce because the chromosomes are small (< 2 μm). In this work, we carried out a karyotypic analysis of 15 species of Myrtaceae grouped in different subtribes and genera. Measurements of chromosome length (long arm, L ; short arm, S ) were taken and several karyotypic parameters were calculated for each species. The karyotypes in fleshy-fruited taxa (Myrteae) were more varied than in the other previously analysed dry-fruited group ( Eucalyptus , Eucalypteae), in which the chromosomes were exclusively metacentric.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155 , 571–580.     

Genetic portrait of Lisboa immigrant population from Cabo Verde with mitochondrial DNA analysis

Journal of Genetics -     

Proteomic analysis of 3T3-L1 adipocyte mitochondria during differentiation and enlargement

The increase in adipose tissue mass arises in part from progressive lipid loading and triglyceride accumulation in adipocytes. Enlarged adipocytes produce the highest levels of pro-inflammatory molecules and reactive oxygen species (ROS). Since mitochondria are the site for major metabolic processes (e.g., TCA cycle) that govern the extent of triglyceride accumulation as well as the primary site of ROS generation, we quantitatively investigated changes in the adipocyte mitochondrial proteome during different stages of differentiation and enlargement. Mitochondrial proteins from 3T3-L1 adipocytes at different stages of lipid accumulation (days 0-18) were digested and labeled using the iTRAQ 8-plex kit. The labeled peptides were fractionated using a liquid phase isoelectric fractionation system (MSWIFT) to increase the depth of proteome coverage and analyzed using LC-MS/MS. A total of 631 proteins in the mitochondrial fraction, including endoplasmic reticulum-associated and golgi-related mitochondrial proteins, were identified and classified into 12 functional categories. A total of 123 proteins demonstrated a statistically significant change in expression in at least one of the time points over the course of the experiment. The identified proteins included enzymes and transporters involved in the TCA cycle, fatty acid oxidation, and ATP synthesis. Our results indicate that cultured adipocytes enter a state of metabolic-overdrive where increased flux through the TCA cycle and increased fatty acid oxidation occur simultaneously. The proteomic data also suggest that accumulation of reduced electron carriers and the resultant oxidative stress may be attractive targets for modulating adipocyte function in metabolic disorders.     

功能矫形前伸青春期大鼠下颌后浅层嚼肌细胞凋亡的研究

目的：研究功能矫形前伸大鼠下颌后浅层嚼肌细胞凋亡的变化规律,探讨功能矫形的肌肉改建机理。方法：选用50只5周龄Sprague-Dawley（SD）雄性大白鼠,随机分为实验组和对照组各25只。实验组大鼠戴自制上颌功能矫治嚣,引导下颌前伸,并打开咬合。利用RT-PCR方法检测两组大鼠浅层嚼肌Bcl-2和Bax基因表达情况,利用TUNEL方法检测浅层嚼肌细胞凋亡情况。结果：①Bcl-2和Bax基因表达随大鼠戴用矫治器时间的延长而升高,至第3周开始下降但仍高于对照组,但Bax的表达高于Bcl-2。Bax/Bcl-2比值随大鼠戴用矫治器时间的延长而升高,至第4周开始下降。②TUNEL实验结果显示浅层嚼肌细胞在戴用矫治器1天后,开始出现凋亡,随着时间延长而增加,至第3周达到顶峰,第4周开始下降。结论：①Bax/Bcl-2比值升高促进浅层嚼肌细胞凋亡。②功能矫形可引起浅层嚼肌细胞凋亡,导致肌肉的结构和功能发生适应性改建。     

功能矫形前伸青春期大鼠下颌后翼外肌MyoD、myogenin的表达

目的：探讨＂应力-生长（改建）＂在细胞水平上的体现,为功能矫形治疗和矫治效果的保持提供新思路和实验依据。方法：本实验选用20只4周龄,雄性SD大鼠随机分为8组。其中实验组大鼠经戊巴比妥麻醉后佩戴上颌斜面导板,对照组未佩用。依据时间不同又分为四组：1d,7d,14d,21d。采用RT-PCR技术分析各组大鼠翼外肌组织中肌分化相关基因MyoD、myogenin mRNA的表达变化。结果：未施加功能矫形力的大鼠翼外肌组织MyoD表达伴随其生长发育呈现递减趋势,实验组在第7 d出现表达上调。同时,力学刺激后实验组动物myogenin的表达与对照组相比较在14 d组出现明显上调。结论：功能矫形力作用于翼外肌组织可以诱导MyoD和myogenin的表达上调进而诱导成肌细胞的分化。     

基于钙黄绿素- 铜(Ⅱ)荧光体系测定乙酰半胱氨酸

目的:基于钙黄绿素-铜(Ⅱ)荧光体系测定乙酰半胱氨酸。方法:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,以492 nm为激发波长,520 nm为发射波长测定乙酰半胱氨酸溶液的荧光强度。结果:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,二价铜离子与钙黄绿素配位引起荧光猝灭。由于乙酰半胱氨酸中巯基上的硫离子与Cu2+的亲和力很强,可从钙黄绿素-铜(Ⅱ)的络合物中夺取铜离子而使钙黄绿素游离出来,从而使体系的荧光得以恢复,并且荧光恢复的程度与加入乙酰半胱氨酸的量在一定范围内成线性。结论:建立了一种测定乙酰半胱氨酸的荧光分析新方法,该方法的线性范围为6.0 10-6～1.4 10-5 mol/L,检出限为4.010-6 mol/L。     

De novo generation of prion strains

Prions are self-replicating proteins that can cause neurodegenerative disorders such as bovine spongiform encephalopathy (also known as mad cow disease). Aberrant conformations of prion proteins accumulate in the central nervous system, causing spongiform changes in the brain and eventually death. Since the inception of the prion hypothesis - which states that misfolded proteins are the infectious agents that cause these diseases - researchers have sought to generate infectious proteins from defined components in the laboratory with varying degrees of success. Here, we discuss several recent studies that have produced an array of novel prion strains in vitro that exhibit increasingly high titres of infectivity. These advances promise unprecedented insight into the structure of prions and the mechanisms by which they originate and propagate.     

An IGF-I promoter polymorphism modifies the relationships between birth weight and risk factors for cardiovascular disease and diabetes at age 36

BACKGROUND: Biochemical testing for pheochromocytoma by measurement of fractionated plasma metanephrines is limited by false positive rates of up to 18% in people without known genetic predisposition to the disease. The plasma normetanephrine fraction is responsible for most false positives and plasma normetanephrine increases with age. The objective of this study was to determine if we could improve the specificity of fractionated plasma measurements, by statistically adjusting for age. METHODS: An age-adjusted metanephrine score was derived using logistic regression from 343 subjects (including 33 people with pheochromocytoma) who underwent fractionated plasma metanephrine measurements as part of investigations for suspected pheochromocytoma at Mayo Clinic Rochester (derivation set). The performance of the age-adjusted score was validated in a dataset of 158 subjects (including patients 23 with pheochromocytoma) that underwent measurements of fractionated plasma metanephrines at Mayo Clinic the following year (validation dataset). None of the participants in the validation dataset had known genetic predisposition to pheochromocytoma. RESULTS: The sensitivity of the age-adjusted metanephrine score was the same as that of traditional interpretation of fractionated plasma metanephrine measurements, yielding a sensitivity of 100% (23/23, 95% confidence interval [CI] 85.7%, 100%). However, the false positive rate with traditional interpretation of fractionated plasma metanephrine measurements was 16.3% (22/135, 95% CI, 11.0%, 23.4%) and that of the age-adjusted score was significantly lower at 3.0% (4/135, 95% CI, 1.2%, 7.4%) (p < 0.001 using McNemar's test). CONCLUSION: An adjustment for age in the interpretation of results of fractionated plasma metanephrines may significantly decrease false positives when using this test to exclude sporadic pheochromocytoma. Such improvements in false positive rate may result in savings of expenditures related to confirmatory imaging.