How do Parkin mutations result in neurodegeneration?

The gene product responsible for autosomal recessive juvenile Parkinsonism, Parkin, has been observed to have ubiquitin ligase activity. This finding has changed the direction of studies on Parkinson's disease by suggesting that abnormal protein turnover might be involved in its pathogenesis. A number of potentially neurotoxic Parkin-specific substrates have been identified. Further investigation of Parkin knockout mice will hopefully provide new evidence in the search for Parkin's substrates and further clarify their role in Parkinson's disease.     

Is regeneration inDrosophila the result of epimorphic regulation?

Summary It has been known for many years that when a wing disc ofDrosophila is bisected, and the fragments cultured in adult females, regulation occurs and either a complete disc is regenerated or the fragment is duplicated. We have investigated how this regeneration process occurs. To establish which cells contribute to the regenerate, and thus determine if regeneration is the result of epimorphic regulation, fragments of discs, after culture in an adult for one to five days, were exposed to³H-thymidine to label replicating cells. Imaginal discs, both whole and as regenerating fragments, undergo some DNA replication which is distributed throughout the disc, but cut discs frequently show clusters of labelled cells around the wound, indicating that regeneration is probably epimorphic.     

Do Bertalanffy's growth curves result from optimal resource allocation?

Bertalanffy's equation is commonly used to model indeterminate growth. Bertalanffy claimed that this growth pattern results from growth potential decreasing with age. An alternative approach provided by life history theory predicts that indeterminate growth is optimal for organisms in a seasonal environment and results not from decreasing growth potential but from allocating increasingly less energy with age into growth, and more into reproduction. Bertalanffy's curves are the result of evolutionary optimization and should not be used in optimization models as an assumption, but they can be used as a tool to describe the indeterminate growth pattern phenomenologically.     

Does dust result in mite outbreaks in apple orchards?

The effect of dust on phytophagous mite numbers was examined in five apple orchards situated in the dry, inland apple producing Ceres area, South Africa. The study was conducted over three seasons. The season with the most dust had the least number of mites. There was no relationship between the amount of dust on leaves and mite numbers from different orchards. Of the 15 correlations between the amount of dust on individual trees and the number of mites on these trees, two were marginally not significant and one was highly significant, but negative. Therefore, seasons during which there is a lot of dust did not result in mite outbreaks nor did dusty orchards harbour elevated mite population levels, and trees with a lot of dust did not necessarily harbour more mites than trees with less dust. However, if there is enough dust to cause stress to the trees, phytophagous mite outbreaks could occur.     

‘PARAMEDIC-2: Big study,small result’

The PARAMEDIC-2 trial demonstrated that the use of adrenaline compared with placebo in out-of-hospital cardiac arrest (OHCA) resulted in a small increase in 30-day survival, but was associated with a higher number of survivors with severe neurological impairment. These findings received a lot of attention, and generated a widespread discussion about the role of adrenaline in cardiac arrest. In this point of view, we aim to place the PARAMEDIC-2 results in the right perspective by comparing the relative effect of adrenaline to other determinants of cerebral blood flow.

     

HPLC-DAD和LC/MS/MS测定豆奶中三聚氰胺

目的：建立二极管阵列高效液相色谱仪和三重四级杆液质联用仪对豆奶中三聚氰胺的测定方法。方法：采用三氯乙酸和乙腈为提取剂、蛋白质为沉淀剂,提取液过净化柱纯化。结果：三重四级杆液质联用法对三聚氰胺的检出限为0-001 5 mg/kg,标准曲线在0-01~0-5 μg/mL范围内,R2为0-999 8,线性良好,再回收率为85 %~89 %,适用于检测低浓度的样品;二极管阵列高效液相色谱法检出限为0-024 mg/kg,标准曲线在0-5~100 μg/mL范围内,R2为0-999 9,线性良好,回收率为83 %~91 %,可以快速地对高浓度样品进行筛查。结论以上两种检测方法结合使用,可检测0-01~100 mg/kg的三聚氰胺含量,极大地拓宽了检测范围。     

GC–MS and GC–MS/MS measurement of the cardiovascular risk factor homoarginine in biological samples

l-Homoarginine (hArg) has recently emerged as a novel cardiovascular risk factor and to herald a poor prognosis in heart failure patients. Here, we report on the development and thorough validation of gas chromatography–mass spectrometry (GC–MS) and gas chromatography–tandem mass spectrometry (GC–MS/MS) methods for the quantitative determination of hArg in biological samples, including human plasma, urine and sputum. For plasma and serum samples, ultrafiltrate (10 µL; cutoff, 10 kDa) was used. For urine samples, native urine (10 µL) was used. For sputum, protein precipitation by acetone was performed. hArg is derivatized to its methyl ester tri(N-pentafluoropropionyl) derivative; de novo synthesized trideutero-methyl ester hArg is used as the internal standard (IS). Alternatively, [guanidino-¹⁵N₂]-arginine can be used as an IS. Quantitative analyses were performed after electron-capture negative-ion chemical ionization by selected-ion monitoring in GC–MS and selected-reaction monitoring in GC–MS/MS. We obtained very similar hArg concentrations by GC–MS and GC–MS/MS, suggesting that GC–MS suffices for accurate and precise quantification of hArg in biological samples. In plasma and serum samples of the same subjects very close hArg concentrations were measured. The plasma-to-serum hArg concentration ratio was determined to be 1.12 ± 0.21 (RSD, 19 %), suggesting that blood anticoagulation is not a major preanalytical concern in hArg analysis. In healthy subjects, the creatinine-corrected urinary excretion of hArg varies considerably (0.18 ± 0.22 µmol/mmol, mean ± SD, n = 19) unlike asymmetric dimethylarginine (ADMA, 2.89 ± 0.89 µmol/mmol). In urine, hArg correlated with ADMA (r = 0.475, P = 0.040); in average, subjects excreted in the urine about 17.5 times more ADMA than hArg. In plasma of healthy humans, the concentration of hArg is of the order of 2 µM. hArg may be a low-abundance constituent of human plasma proteins. The GC–MS and GC-MS/MS methods we report in this article are useful to study the physiology and pathology of hArg in experimental and clinical settings.     

Does prescribed burning result in biotic homogenization of coastal heathlands?

Biotic homogenization due to replacement of native biodiversity by widespread generalist species has been demonstrated in a number of ecosystems and taxonomic groups worldwide, causing growing conservation concern. Human disturbance is a key driver of biotic homogenization, suggesting potential conservation challenges in seminatural ecosystems, where anthropogenic disturbances such as grazing and burning are necessary for maintaining ecological dynamics and functioning. We test whether prescribed burning results in biotic homogenization in the coastal heathlands of north‐western Europe, a seminatural landscape where extensive grazing and burning has constituted the traditional land‐use practice over the past 6000 years. We compare the beta‐diversity before and after fire at three ecological scales: within local vegetation patches, between wet and dry heathland patches within landscapes, and along a 470 km bioclimatic gradient. Within local patches, we found no evidence of homogenization after fire; species richness increased, and the species that entered the burnt Calluna stands were not widespread specialists but native grasses and herbs characteristic of the heathland system. At the landscapes scale, we saw a weak homogenization as wet and dry heathland patches become more compositionally similar after fire. This was because of a decrease in habitat‐specific species unique to either wet or dry habitats and postfire colonization by a set of heathland specialists that established in both habitat types. Along the bioclimatic gradient, species that increased after fire generally had more specific environmental requirements and narrower geographical distributions than the prefire flora, resulting in a biotic ‘heterogenisation’ after fire. Our study demonstrates that human disturbance does not necessarily cause biotic homogenization, but that continuation of traditional land‐use practices can instead be crucial for the maintenance of the diversity and ecological function of a seminatural ecosystem. The species that established after prescribed burning were heathland specialists with relatively narrow geographical ranges.     

BIA–MS–MS: biomolecular interaction analysis for functional proteomics

One of the experimental processes of functional proteomics is the analysis of protein interaction. Here, we review a new analytical platform, BIA–MS, for protein interaction analysis. BIA–MS is an integration of a surface plasmon resonance biosensor for real-time interaction analysis and mass spectrometry for the subsequent identification of interacting molecules.     

BIA–MS–MS: biomolecular interaction analysis for functional proteomics

One of the experimental processes of functional proteomics is the analysis of protein interaction. Here, we review a new analytical platform, BIA–MS, for protein interaction analysis. BIA–MS is an integration of a surface plasmon resonance biosensor for real-time interaction analysis and mass spectrometry for the subsequent identification of interacting molecules.     

MS基因缺失的发现

衣阿华大学(Iowa City,IA)和法国的科研人员发现,第17条染色体上缺失adhalin基因可引起严重型儿童常染色体退行性肌营养不良(SCARMD)。该病能引起严重的随意肌功能丧失。 基因的缺失能导致肌蛋白adhalin的缺乏,该蛋白能在肌肉受损害收缩过程中保护肌肉细胞。受此病折磨的患者第17条染色体上缺失2个adhalin基因,它们分别来自患者的双亲。在不久的将来,将通过基     

Asymmetry in spider orb webs: a result of physical constraints?

A typical feature of most vertical orb webs is that the upper web region is smaller and contains less silk than the lower web region, creating an asymmetrical web. The degree of web asymmetry changes during the spider's development: small juveniles construct more symmetrical webs, but older and larger individuals decrease the upper web region. This implies that weight may control the extent of web asymmetry. Using two species, Argiope keyserlingi and Larinioides sclopetarius, we tested the effect of weight increase on web asymmetry by naturally increasing weight through feeding and by artificially adding lead weights to the abdomen of the spiders. Weight increase (natural or artificial) resulted in more asymmetric webs through a reduction of the upper web region. Added weight may interfere with spiral placement in the upper region, because the spider has to lift its abdomen above the carapace during the process. In the lower region, however, the position of the spider is mostly head up during spiral placement. Therefore, amongst other factors, weight and gravitational forces may be physical constraints during web construction. Copyright 1999 The Association for the Study of Animal Behaviour.     

Allelic heterogeneity of Crooked Tail Syndrome: result of balancing selection?

We report the identification of a second loss-of-function mutation (c.1906T>C) in the bovine MRC2 gene causing the Crooked Tail Syndrome in Belgian Blue Cattle. We demonstrate that the ensuing substitution of the highly conserved Cysteine 636 with Arginine causes illegitimate receptor oligomerization, which is predicted to impair function of the MRC2 encoded protein, Endo180. We propose that this second MRC2 mutation was selected by breeders as a result of its favourable effect on muscularity in heterozygotes.     

Cognitive abilities - the result of selective pressures on food acquisition?

Locating and capturing food are suggested as significant selection pressures for the evolution of various cognitive abilities in mammals and birds. The hypothesis is proposed that aspects of food procuring behaviour should be strongly indicative of particular cognitive abilities.Experimental data concerning higher mental abilities in mammals and birds are reviewed. These data deal with self-recognition studies, rule-learning experiments, number concept, deceptive abilities, tool-use and observational learning.A Darwinian approach reveals: (1) the adaptiveness of particular abilities for particular niches, (2) that in complex foraging environments, increases in foraging efficiencies in animals should result from the evolution of particular cognitive abilities, (3) that phenomena such as convergent mental evolution should be expected to have taken place across taxonomic groups for species exploiting similar niches, (4) that divergence in mental ability should also have taken place where related species have exploited dissimilar niches.Experimental data of higher mental abilities in animals concur with a Darwinian explanation for the distribution of these cognitive abilities and no anomalies have been found.There are, as a consequence, significant implications for the welfare of animals subject to training when training methodology gives little or no consideration to the various mental abilities of species.     

Will knowledge of human genome variation result in changing cancer paradigms?

Our incomplete understanding of carcinogenesis may be a significant reason why some cancer mortality rates are still increasing. This lack of understanding is likely due to a research approach that relies heavily on genetic comparison between cancerous and non-cancerous tissues and cells, which has led to the identification of genes of cancer proliferation rather than differentiation. Recent observations showing that a tremendous degree of natural human genetic variation occurs are likely to lead to a shift in the basic paradigms of cancer genetics, in that there is a need to consider both the nature of the genes involved, and the idea that not every genetic variation identified in these genes may be associated with carcinogenesis. Based on studies using LCM and micro-genetic analyses, we propose that significant cancer initiating events may take place during the very early stages of development of cancer-susceptible tissues and that using such techniques might greatly help us in our understanding of carcinogenesis.     

What will result from the interaction between functional and evolutionary biology?

The modern synthesis has been considered to be wrongly called a "synthesis", since it had completely excluded embryology, and many other disciplines. The recent developments of Evo-Devo have been seen as a step in the right direction, as complementing the modern synthesis, and probably leading to a "new synthesis". My argument is that the absence of embryology from the modern synthesis was the visible sign of a more profound lack: the absence of functional biology in the evolutionary synthesis. I will consider the reasons for this absence, as well as the recent transformations which favoured a closer interaction between these two branches of biology. Then I will describe two examples of recent work in which functional and evolutionary questioning were tightly linked. The most significant part of the paper will be devoted to the transformation of evolutionary theory that can be expected from this encounter: a deep transformation, or simply an experimental confirmation of this theory? I will not choose between these two different possibilities, but will discuss some of the difficulties which make the choice problematic.