米兰-《科学》（20241011出版）一周论文导读—新闻—科学网

Science, VOLUME 386,ISSUE 6718,11 OCT 2024

《科学》第386卷，6718期，2024年10月11日

生态Ecology

Hidden comet tails of marine snow impede ocean-based carbon sequestration

“海洋雪”中的埋没“彗尾”有碍海洋碳封存

▲ 作者：RAHUL CHAJWA, ELIOTT FLAUM, KAY D. BIDLE, BENJAMIN VAN MOOY, AND MANU PRAKASH

▲链接：

https://www.science.org/doi/10.1126/science.adl5767

▲摘要：

下沉的海洋微粒有机物资，凡是被称为“海洋雪”，将年夜量的碳从海洋概况转移到深处，组成了地球碳轮回的首要构成部门之一。这些粒子的生物和物理复杂性，和其活动中所触及的长度和时候标准的普遍规模，使得具体肯定它们的动力学变得极为坚苦。

Chajwa等人利用显微成像手艺发现，这些颗粒遍及表示出尾巴状的活动形态，这极年夜地影响了它们的活动和它们在深海中封存了几多碳。

▲ Abstract：

Sinking marine particulate organic matter, commonly called “marine snow,” moves huge amounts of carbon from the new-surface ocean to depth, constituting one of the major components of Earth’s carbon cycle. The biological and physical complexity of these particles, together with the wide range of lengths and timescales that are involved in their motion, have made it exceedingly difficult to determine their dynamics in detail. Chajwa et al. used microscopic imaging to show that these particles universally exhibit a tail-like flow morphology that greatly influences their movement and how much carbon they sequester in the deep ocean.

Ecological speciation in Darwin’s finches: Ghosts of finches future

达尔文雀的生态物种构成：雀类将来的鬼魂

▲ 作者：JEFFREY PODOS AND KATIE M. SCHROEDER

▲链接：

https://www.science.org/doi/10.1126/science.adj4478

▲摘要：

当我们想到一个物种顺应情况转变时，凡是会想到一个特点。但是，一个特点的改变可能会影响到其他特点。在Galapagos雀类中，已证实干旱会致使喙的巨细和外形产生转变，以响应种子资本的转变。

但是，鸟类不但用喙吃饭，还用喙唱歌。Podos和Schroeder猜测了鸟的巨细若何跟着一系列干旱而转变，并猜测了它们会发出的歌曲。他们发现，在一系列摹拟干旱以后，这些歌曲的差别足够年夜，以致在领地雄性鸟类不再辨认它们。

▲ Abstract：

When we think of a species adapting to environmental change, we mostly think about one trait. However, changes in one trait will likely affect others. In Galápagos finches, it has been shown that drought can lead to a change in bill size and shape in response to shifts in seed resources. However, birds do not just eat with their bills, they also sing with them. Podos and Schroeder predicted how bill size would change in response to a series of droughts and forecasted the songs that they would produce. They found that, after a series of simulated droughts, the songs differed enough that territorial male birds no longer recognized them.

化学Chemistry

Catalytic asymmetric fragmentation of cyclopropanes

环丙烷催化不合错误称裂解

▲ 作者：RAVINDRA KRUSHNAJI RAUT, SATOSHI MATSUTANI, FUXING SHI, SHUTA KATAOKA, MARGARETA POJE, BENJAMIN MITSCHKE, SATOSHI MAEDA, NOBUYA TSUJI , AND BENJAMIN LIST

▲链接：

https://www.science.org/doi/10.1126/science.adp9061

▲摘要：

曩昔半个世纪，有机化学家设计了很多催化剂，它们只能发生两种可能的镜像（对映体）产品中的一种。年夜大都环境下，这些催化剂依靠在氧或氮原子的连系位点。跟着反映的进行，缺少这些位点的纯碳氢化合物很难在空间上发生误差。

研究者报导了一类手性酸，咪胺二磷酰亚胺酸，可以包裹对称的环丙烷并催化其开环重排，以传递具有高对映选择性的手性烯烃化合物。

▲ Abstract：

Over the past half-century, organic chemists have devised numerous catalysts that deliver just one of two possible mirror-image (enantiomeric) products. For the most part, these catalysts rely on binding sites with oxygen or nitrogen atoms; pure hydrocarbons lacking such sites are much harder to bias spatially as the reaction ensues. Raut et al. now report that a class of chiral acids, imidodiphosphorimidates, can envelop symmetrical cyclopropanes and catalyze their ring-opening rearrangement to deliver chiral olefinic compounds with high enantioselectivity.

Catalytic prenyl conjugate additions for synthesis of enantiomerically enriched PPAPs

催化戊烯基共轭加成物合成对映体富集PPAPs

▲ 作者：SHAWN NG, CASEY HOWSHALL, THANH NHAT HO, BINH KHANH MAI, YUEBIAO ZHOU, CAN QIN, KAI ZE TEE, PENG LIU, FILIPPO ROMITI, AND AMIR H. HOVEYDA

▲链接：

https://www.science.org/doi/10.1126/science.adr8612

▲摘要：

戊烯基是一种疏水的五碳片断，在生物化学和自然产品化学中普遍存在。具有普遍药用价值的自然产物——多环聚戊烯基酰基间苯三酚（PPAPs），一向是多个合成研究的方针，但不合错误称地引入戊烯基已被证实是一个持久的挑战。

Ng等人报导了一种铜催化的方式，使不饱和酮戊酰化，从而取得具有高对映选择性的PPAP。该方式的要害是一种有机硼酸盐试剂，硼在一个有点背反直觉的位置。

▲ Abstract：

The prenyl group is a hydrophobic five-carbon fragment common across a wide range of contexts in biochemistry and natural product chemistry. One extensive class of natural products of pharmaceutical interest, polycyclic polyprenylated acylphloroglucinols (PPAPs), has been the target of multiple synthetic studies, but the introduction of the prenyl groups asymmetrically has proven to be an enduring challenge. Ng et al. now report a copper-catalyzed method to prenylate unsaturated ketones and thereby access PPAPs with high enantioselectivity. Key to the method is an organoborate reagent with the boron in a somewhat counterintuitive position.

物理学Physics

Direct optical measurement of intramolecular distances with angstrom precision

用埃精度直接光学丈量份子内距离

▲ 作者：STEFFEN J. SAHL, JESSICA MATTHIAS, KAUSHIK INAMDAR, MICHAEL WEBER, TAUKEER A. KHAN, CHRISTIAN BRüSER, STEFAN JAKOBS, STEFAN BECKER, CHRISTIAN GRIESINGER, AND STEFAN W. HELL

▲链接：

https://www.science.org/doi/10.1126/science.adj7368

▲摘要：

在纳米标准上直接丈量距离对光学手艺来讲是一个挑战，即便对那些利用亚衍射分辩率荧鲜明微镜的人来讲也是如斯。Sahl等人改良了一种名为MINFLUX的光学方式，可以切确丈量1~10纳米规模内的份子内距离，而对倾斜的份子，则可以丈量1纳米以下的份子内距离。他们利用聚脯氨酸尺，演示了具有已知个位数纳米间距的荧光团的分辩率。

他们将这类方式利用在光活化染料标识表记标帜的卵白质的年夜份子间和年夜份子内丈量，包罗距离对今朝的间接方式来讲太短。成像尝试证实了该手艺在研究细胞中卵白质-卵白质彼此感化方面的潜力。

▲ Abstract：

Measuring distances directly at the nanometer scale is a challenge for optical techniques, even for those using subdiffraction-resolution fluorescence microscopy. Sahl et al. refined an optical approach called MINFLUX such that they could measure precise intramolecular distances in the 1- to 10-nanometer range and below 1 nanometer for molecules with a tilt. Using a polyproline ruler, the authors demonstrate resolution of fluorophores with known single-digit nanometer spacing. They applied this approach to inter- and intramacromolecular measurements of proteins labeled with photoactivatable dyes, including distances too short for current indirect methods. Imaging experiments demonstrated the potential of this technique to study protein-protein interactions in cells.

Polar and quasicrystal vortex observed in twisted-bilayer molybdenum disulfide

扭曲双层二硫化钼中不雅察到极性和准晶涡旋

▲ 作者：CHI SHING TSANG, XIAODONG ZHENG, TONG YANG, ZHANGYUAN YAN, WEI HAN, LOK WING WONG, HAIJUN LIU, SHAN GAO, KA HO LEUNG, AND THUC HUE LY

▲链接：

https://www.science.org/doi/10.1126/science.adp7099

▲摘要：

对扭曲二硫化钼（MoS2）双份子层中电场的不雅察揭露了与扭曲角有关的面内手性涡域。

Tsang等人利用四维扫描透射电子显微镜和第一性道理计较来肯定局部极性域布局，这多是由扭曲堆叠引发的电荷从头分派和小的平面内离子位移引发的。年夜扭角处可见马赛克手性涡。一个12层的准晶体双层具有复杂的涡旋图案，可以经由过程在显微镜下置换层来调剂。

▲ Abstract：

Observations of electric fields in twisted molybdenum disulfide bilayers have revealed in-plane chiral vortex domains that depend on the twist angle. Tsang et al. used four-dimensional scanning transmission electron microscopy (TEM) and first-principles calculations to determine local polar domain structures, which may arise from twist stacking-induced charge redistribution and small in-plane ionic displacements. Mosaic chiral vortex patterns were seen for large twist angles. A 12-fold quasicrystal bilayer had complex vortex patterns that could be tuned by displacing layers within the microscope.

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