Comment on papers by Evans et al. and Mekel-Bobrov et al. on Evidence for Positive Selection of MCPH1 and ASPM

Evans et al. and Mekel-Bobrov et al. (Reports, 9 September 2005, p. 1717 and 1720, respectively) reported that human genetic variants of Microcephalin (MCPH1) and abnormal spindle-like microcephaly associated (ASPM) are under strong positive selection. We genotyped these variants in 9000 children and find no meaningful associations with brain size and various cognitive measures, which indicates that contrary to previous speculations, ASPM and MCPH1 have not been selected for brain-related effects.     

Structural biology. The ribosome is a ribozyme

Ribosomes, the cellular factories that manufacture proteins, contain both RNA and protein, but exactly how all of the different ribosomal components contribute to protein synthesis is still not clear. Now, as Thomas Cech explains in his Perspective, atomic resolution of the structure of the large ribosomal subunit reveals that, as predicted by those convinced of a prebiotic RNA world, RNA is the catalytic component with proteins being the structural units that support and stabilize it (Ban et al., Nissen et al., Muth et al.).     

富民枳的生物学特性及利用研究初报

 富民枳树体大小与普通枳相当,其发育正常的两性花少,结实率低;种子或分株繁殖均易;作砧嫁接柑桔,结果早,株型矮化,是柑桔优良的矮化砧。     

山西代县半夏高产低耗施肥技术研究

运用二次通用旋转组合设计的方案探明N,P,K三种肥料分别对代半夏产量的显著影响,以及N,P,K的互作效应对代半夏产量的响应进行分析,为代半夏高产建立数学模型,提出了代半夏高产低耗施肥方案.结果表明:磷肥的效应大于氮肥,氮肥的效应大于钾肥,磷钾超过最佳肥量后将导致减产.单独施用N,P,K三种肥料达到最高产量的用量分别为:408.7、936.2、302.6 kg/hm2;磷钾互作效应达到显著值,在氮肥用量为225kg/hm2磷钾施肥量分别为1 071、330.3 kg/hm2时,产量达到最大4 797.1 kg/hm2,比单独使用磷钾肥达到的最大值分别增产2%,1%;通过建立的数据模型,得知95%置信域下,获得产量在4 500 kg/hm2以上,纯收入在4200元/亩以上的3种肥料施用的最佳范围:尿素,289.6～335.9kg/hm2;过磷酸钾,957.2～1 140.44kg/hm2;硫酸钾,267.86～323.26 kg/hm2.     

Immunological reversal of autoimmune diabetes without hematopoietic replacement of beta cells

Type 1 diabetes mellitus results from the autoimmune destruction of the beta cells of the pancreatic islets of Langerhans and is recapitulated in the nonobese diabetic strain of mice. In an attempt to rescue islet loss, diabetic mice were made normoglycemic by islet transplantation and immunization with Freund's complete adjuvant along with multiple injections of allogeneic male splenocytes. This treatment allowed for survival of transplanted islets and recovery of endogenous beta cell function in a proportion of mice, but with no evidence for allogeneic splenocyte-derived differentiation of new islet beta cells. Control of the autoimmune disease at a crucial time in diabetogenesis can result in recovery of beta cell function.     

Islet recovery and reversal of murine type 1 diabetes in the absence of any infused spleen cell contribution

A cure for type 1 diabetes will probably require the provision or elicitation of new pancreatic islet beta cells as well as the reestablishment of immunological tolerance. A 2003 study reported achievement of both advances in the NOD mouse model by coupling injection of Freund's complete adjuvant with infusion of allogeneic spleen cells. It was concluded that the adjuvant eliminated anti-islet autoimmunity and the donor splenocytes differentiated into insulin-producing (presumably beta) cells, culminating in islet regeneration. Here, we provide data indicating that the recovered islets were all of host origin, reflecting that the diabetic NOD mice actually retain substantial beta cell mass, which can be rejuvenated/regenerated to reverse disease upon adjuvant-dependent dampening of autoimmunity.     

柑橘等果实糖代谢及其生态调控研究进展

综述了果实内糖的运输及蔗糖代谢相关酶对柑橘等果实的糖代谢的调控机制,以及生态因子对糖代谢过程中糖跨膜运输及果实内蔗糖代谢相关酶基因的调控方式,并指出运用分子生物学手段研究果实糖代谢相关酶基因的调控机理和生态因子对果实内糖代谢的影响为今后研究的重点方向。     

Immunology. Long live the mature B cell--a baffling mystery resolved

What determines whether transitional B cells newly emerged from the bone marrow will differentiate further to become mature, long-lived, circulating B lymphocytes? In a Perspective, Waldschmidt and Noelle discuss new findings showing that the TNF family ligand BAFF and its receptor BAFF-R are crucial for selecting transitional B cells into the mature B cell pool (Thompson et al., Schiemann et al.).     

Development. Endothelium--chicken soup for the endoderm

Endothelial cells in blood vessels are known to be important during the later stages of organ development in the embryo. However, their involvement at the induction stage of organ formation has not been previously documented. As Bahary and Zon explain in their Perspective, new work demonstrates that endothelial cells secrete factors early in development that induce embryonic endoderm to become liver or pancreas (Matsumoto et al., Lammert et al.).     

Chemistry. Superacids--it's al lot about anions

Superacids are powerful agents for protonating weak bases, with applications ranging from synthetic chemistry to batteries and fuel cells. DesMarteau explains in his Perspective that many superacids have undesirable properties, because after proton donation, the resulting anion may interact strongly with the protonated base or the solvent. Reed et al. report the discovery of a superacid that overcomes this problem. In the anion, charge is distributed efficiently over many atoms, reducing unwanted interactions.     

Comment on "Orthographic processing in baboons (Papio papio)"

Grainger et al. (Reports, 13 April 2012, p. 245) suggest that baboons can discriminate words from nonwords on the basis of two-letter (bigram) frequencies. This ability can also be attributed to baboons being able to recognize specific letters (i.e., shapes) in specific positions in their four-letter words, without reference to letter or bigram frequencies.     

Comment on "A test of the snowball theory for the rate of evolution of hybrid incompatibilities"

Matute et al. (Reports, 17 September 2010, p. 1518) tested the theory that the number of genes involved in hybrid incompatibility increases faster than linearly. However, the method they used is inappropriate because it detects genes that are haploinsufficient in a hybrid background but that would not contribute to lethality in wild-type hybrids, thus overestimating the frequency of hybrid inviability.     

Erratum

In the report "The color of the surface of Venus" by C. M. Pieters et al. (12 Dec., p. 1379), figure 2 on page 1382 was incorrectly printed upside down. The correct figure and caption appear below. Reference 11 in the caption is to A. S. Selivanov et al., Kosm. Issled. 21, 176 (1983) and A. S. Selivanov et al., ibid., p. 183. [SEE FIGURE 2 IN SOURCE PDF].     

Erratum

In the report "Positron emission tomography reveals elevated D(2) dopamine receptors in drugnaive schizophrenics" by D. F. Wong et al. (19 Dec., p. 1558), reference 8 should have read, "D. F. Wong et al., Science 226, 1393 (1984); D. F. Wong et al., J. Cereb. Blood Flow Metab. 6, 147 ( 1986).     

Retraction

Science is fully retracting the report "Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome" (V. C. Lombardi et al., Science 326, 585 (2009); 10.1126/science.1179052)     

我国藓类植物的一个新记录种—六棱金发藓(Pogonatum hexagonum Mitt)

本文报道了属于金发藓科小金发藓属的藓类植物——六棱金发藓(Pogonatum hexagonum Mitt)。本种在我国的首次发现,为研究我国藓类植物资源及其地理分布,增添了一份新资料。     

Erratum

In the Technical Comment "Trans-activator gene of HTLV-II: Interpretation" by W. C. Greene et al. (27 Feb., p. 1073), the third-from-the-last sentence should have read, "In addition, using Jurkat or other T-cell lines, Inoue and colleagues (2) and Maruyama et al. (3) have described activation of both the IL-2 receptor and IL-2 genes by the tat-I gene isolated from HTLV-I, which shares similar structural and functional properties with the tat-II gene." Reference 3 should have been to M. Maruyama et al., cell 48,343(1987).     

Corrections and clarifications

D. G. Rainnie et al., in their report "Adenosine inhibition of mesopontine cholinergic neurons: Implications for EEG arousal" (4 Feb., p. 689), suggested that adenosine may mediate sleep-debt related potentiation of EEG slow-wave activity in non-REM sleep. This is similar to a hypothesis proposed by J. H. Benington et al. [Sleep Res. 22, 4 (1993)]. Rainnie et al. suggested that adenosine exerts this effect by means of inhibition of mesopontine cholinergic neurons rather than by direct inhibition of neurons in the cerebral cortex.     

Erratum

In the Research Article "The cholinergic neuronal differentiation factor from heart cells is identical to leukemia inhibitory factor" by T. Yamamori et al. (15 Dec., p. 1412), figure 2 (p. 1414) was printed incorrectly. The correct figure appears below. See Table in the PDF file.     

热应激大白鼠脾脏和肝脏组织HSP70和NOS的表达变化

随机选用42只6月龄健康雄性SD大白鼠,研究热应激处理1 h后恢复0、2、4、8、12、48 h6个时段脾脏和肝脏组织热应激蛋白70(HSP70)和一氧化氮合成酶(NOS)免疫组织的化学变化规律.结果表明:(1)热应激处理后恢复4 h,大白鼠脾脏组织HSP70的阳性表达达到高峰,大量细胞破裂,8 h后呈逐渐下降的趋势;恢复0、2、4、8、12 h的阳性表达与对照的差异均达极显著水平(P0.01),恢复48 h的阳性表达与对照的差异不显著(P0.05).(2)热应激处理后各恢复期肝脏组织HSP70的阳性表达与对照的差异均不显著(P0.05).(3)热应激处理后恢复8 h,肝脏组织NOS的阳性表达达到高峰,而后逐渐下降;恢复0、2、4、8、12 h的阳性表达与对照的差异均达极显著水平(P0.01);恢复48 h的阳性表达与对照的差异不显著(P0.05),恢复0、2、4、8、12 h间的阳性表达差异均达极显著水平(P0.01);(4)热应激处理后各恢复期脾脏组织NOS的阳性表达与对照的差异均不明显.