False belief reasoning in the brain: An ERP study

Understanding others mind and interpersonal interaction are the cognitive basis of successful social interactions. People's mental states and behaviors rely on their holding beliefs for self and others. To investigate the neural substrates of false belief reasoning, the 32 channels event-related potentials (ERP) of 14 normal adults were measured while they understood false-belief and true belief used de-ceptive appearance task. After onset of the false-belief or true-belief questions, N100, P200 and late negative component (LNC) were elicited at centro-frontal sites. Compared with true belief, false belief reasoning elicited significant declined LNC in the time window from 400 to 800 ms. The source analysis of difference wave (False minus True) showed a dipole located in the middle cingulated cortex. These findings show that false belief reasoning probably included inhibitive process.     

The incidence, distribution and expression of Australian grapevine yellows, restricted growth and late season leaf curl diseases in selected Australian vineyards

Surveys were conducted in four Chardonnay vineyards for 3 to 6 years and one Shiraz vineyard for 3 years to determine the yearly percentage of grapevines affected by Australian grapevine yellows disease (AGYd), restricted growth disease (RGd) and late season leaf curl disease (LSLCd). In each of the Chardonnay vineyards in each year, all three diseases were characterised by remission of disease in some grapevines, recurrence of disease in other grapevines and new observations of disease in previously unaffected grapevines. The pattern of temporal incidence of each disease was different between vineyards for the survey period. Although Koch's postulates have not been fulfilled, phytoplasmas are considered to be the most likely cause of AGYd. While some grapevines exhibited a combination of AGYd and RGd or AGYd and LSLCd, both RGd and LSLCd can occur independently of AGYd. Statistical analyses using log-linear models also indicated that RGd and LSLCd were not always associated with AGYd. Thus, it is possible that phytoplasmas are not the cause of RGd or LSLCd and their association is coincidental. Expression of AGYd in Shiraz grapevines occurred later in the season compared to Chardonnay. Very little recurrence of AGYd was observed in the Shiraz grapevines indicating that the variety Shiraz responds differently to phytoplasma infections, assuming that AGYd in Shiraz is a phytoplasma caused disease. RGd and LSLCd were not observed on any grapevines in the Shiraz vineyard.     

Cold stability of intrinsically disordered proteins

Contrary to globular proteins, intrinsically disordered proteins (IDPs) lack a folded structure and they do not lose solubility at elevated temperatures. Although this should also be true at low temperatures, cold stability of IDPs has not been addressed in any scientific work so far. As direct characterization of cold-denaturation is difficult, we approached the problem through a freezing-induced loss-of-function model of globular-disordered functional protein pairs (m-calpain-calpastatin, tubulin-Map2c, Hsp90-ERD14). Our results affirm that in contrast with globular proteins IDPs are resistant to cold treatment. The theoretical and functional aspects of this observation are discussed.     

Both plant and animal LEA proteins act as kinetic stabilisers of polyglutamine-dependent protein aggregation

LEA (late embryogenesis abundant) proteins are intrinsically disordered proteins that contribute to stress tolerance in plants and invertebrates. Here we show that, when both plant and animal LEA proteins are co-expressed in mammalian cells with self-aggregating polyglutamine (polyQ) proteins, they reduce aggregation in a time-dependent fashion, showing more protection at early time points. A similar effect was also observed in vitro, where recombinant LEA proteins were able to slow the rate of polyQ aggregation, but not abolish it altogether. Thus, LEA proteins act as kinetic stabilisers of aggregating proteins, a novel function in protein homeostasis consistent with a proposed role as molecular shields.     

番茄RGA4蛋白与马铃薯Rpi-blb1蛋白的同源比较分析

为获得番茄抗晚疫病广谱性基因信息,采用同源电子克隆法,基于番茄蛋白序列数据库,以马铃薯晚疫病广谱抗性蛋白Rpi-blb1为种子序列,获得番茄疾病抗性蛋白RGA4,并进行基因电子定位和基因结构、模体、二级结构、基因进化及基因电子表达等分析,以证明两者的进化关系。结果表明:番茄RGA4蛋白(XP_004245923.1)序列具有NB-ARC和LRR8两个保守结构域,定位于第8条染色体SL2.40区间,相应基因位于8号染色体序列的57228847-57232935 bp区间,长度为4 089 bp,由2个外显子和1个内含子组成,编码988个氨基酸序列,该蛋白为不稳定分泌球形蛋白;番茄RGA4蛋白和马铃薯Rpi-blb1蛋白在二级结构分布、基因序列组成、基因定位等方面相似性较高,可确定两者为垂直同源关系,但在基因进化和模体组成方面存在差异,可能导致两者功能上的不同。研究结果可为番茄晚疫病广谱抗性基因克隆及其利用提供理论依据。     

Biochemical and structural characterization of an endoplasmic reticulum-localized late embryogenesis abundant (LEA) protein from the liverwort Marchantia polymorpha

Late embryogenesis abundant (LEA) proteins, which accumulate to high levels in seeds during late maturation, are associated with desiccation tolerance. A member of the LEA protein family was found in cultured cells of the liverwort Marchantia polymorpha; preculture treatment of these cells with 0.5 M sucrose medium led to their acquisition of desiccation tolerance. We characterized this preculture-induced LEA protein, designated as MpLEA1. MpLEA1 is predominantly hydrophilic with a few hydrophobic residues that may represent its putative signal peptide. The protein also contains a putative endoplasmic reticulum (ER) retention sequence, HEEL, at the C-terminus. Microscopic observations indicated that GFP-fused MpLEA1 was mainly localized in the ER. The recombinant protein MpLEA1 is intrinsically disordered in solution. On drying, MpLEA1 shifted predominantly toward α-helices from random coils. Such changes in conformation are a typical feature of the group 3 LEA proteins. Recombinant MpLEA1 prevented the aggregation of α-casein during desiccation–rehydration events, suggesting that MpLEA1 exerts anti-aggregation activity against desiccation-sensitive proteins by functioning as a “molecular shield”. Moreover, the anti-aggregation activity of MpLEA1 was ten times greater than that of BSA or insect LEA proteins, which are known to prevent aggregation on drying. Here, we show that an ER-localized LEA protein, MpLEA1, possesses biochemical and structural features specific to group 3 LEA proteins.     

新疆玛纳斯古近纪—新的鲤科鱼类

记述了新疆玛纳斯古近纪安集海河组发现的鲤科(Cyprinidae)一新属、种——刘氏天山鱼(Tianshanicus liui gen.et sp.nov.)。新属具有臀鳍分叉鳍条多于7根、体长形稍侧扁、口端位、下咽齿近锥形而齿尖前后略侧扁、背鳍和臀鳍均无硬棘、背鳍起点略在腹鳍起点之后以及尾鳍深分叉等特征,表明它应属于雅罗鱼亚科(Leuciscinae sensu Cavender & Coburn,1992)。然而,它又具有额骨前宽后窄、顶骨长方形、膜质蝶耳骨很大、齿骨冠状突较低、鳃盖骨近长方形等特征而有别于本亚科中其他属。值得注意的是,这些特征却见诸于现生的胭脂鱼类Myxocyprinus中,这将对研究雅罗鱼类的起源很有意义。根据鱼化石和哺乳化石的证据,认为含鱼层的时代为晚始新世。     

Engineering high α‐amylase levels in wheat grain lowers Falling Number but improves baking properties

Late maturity α‐amylase (LMA) and preharvest sprouting (PHS) are genetic defects in wheat. They are both characterized by the expression of specific isoforms of α‐amylase in particular genotypes in the grain prior to harvest. The enhanced expression of α‐amylase in both LMA and PHS results in a reduction in Falling Number (FN), a test of gel viscosity, and subsequent downgrading of the grain, along with a reduced price for growers. The FN test is unable to distinguish between LMA and PHS; thus, both defects are treated similarly when grain is traded. However, in PHS‐affected grains, proteases and other degradative process are activated, and this has been shown to have a negative impact on end product quality. No studies have been conducted to determine whether LMA is detrimental to end product quality. This work demonstrated that wheat in which an isoform α‐amylase (TaAmy3) was overexpressed in the endosperm of developing grain to levels of up to 100‐fold higher than the wild‐type resulted in low FN similar to those seen in LMA‐ or PHS‐affected grains. This increase had no detrimental effect on starch structure, flour composition and enhanced baking quality, in small‐scale 10‐g baking tests. In these small‐scale tests, overexpression of TaAmy3 led to increased loaf volume and Maillard‐related browning to levels higher than those in control flours when baking improver was added. These findings raise questions as to the validity of the assumption that (i) LMA is detrimental to end product quality and (ii) a low FN is always indicative of a reduction in quality. This work suggests the need for a better understanding of the impact of elevated expression of specific α‐amylase on end product quality.