Did planetary collisions transform moon chemistry?


Research Report

By Lynne Friedmann

Fresh examination of lunar rocks collected more than 40 years ago, is providing new insights about the moon’s chemical makeup as well as clues about giant impacts that may have also shaped Earth’s early beginnings.

Using advanced mass-spectrometer technology, researchers at the Scripps Institution of Oceanography at UC San Diego and Washington University, in St. Louis, compared the chemical signatures of rocks obtained during four lunar missions to lunar meteorites collected from Antarctica. The rocks reveal that the volatile element zinc is severely depleted on the moon, along with similar elements.

Researchers argue this is evidence of a large-scale evaporation of zinc caused by a dramatic event rather than small-scale volcanic processes over time. Such a cataclysmic event would require gigantic planetary collisions (likely just after the solar system formed) to generate the heat necessary for wholesale evaporation of the zinc. Furthermore, such collisions might have blasted precious metals, such as gold and platinum, from the moon to Earth, thus shaping our planet’s chemical composition.

Findings appear in the journal


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Mapping gene activities of individual cells

Bioengineers at the UC San Diego Jacobs School of Engineering have received a $9.3 million grant from the National Institutes of Health to establish a single-cell genomics center and develop a three-dimensional map of gene activities in individual cells in the human cortex; the outer layer of neural tissue responsible for cognitive functions including memory, attention and decision making.

While many studies on human brain functions focus on the neuronal firing and transmission of electrical signals, the underlying activities of all genes in individual neurons and the supporting cells (“glia”) represent another important research aspect. Heretofore, characterizing the activities of all genes in individual brain cells has been extremely difficult due to the technical challenges in handling single cells to extract and characterize individual RNA molecules.

A major goal of the center will be development of novel technology to identify and quantify all RNA molecules — a proxy for gene activity — in 10,000 individual cells from human brains. High-resolution imaging technology will then “anchor” the information collected from each cell to the three-dimensional anatomy of the human brain creating a reference map of human brain gene activity to be used to identify those genes responsible for brain disorders.

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Reversible method of tagging proteins

UC San Diego chemists have developed a novel method that allows the attachment of chemical probes onto proteins and their subsequent removal in a repeatable cycle. The method applied to understanding the biochemistry of naturally formed proteins in order to create better antibiotics, anti-cancer drugs, biofuels, food crops and other natural products. It also provides scientists with a new laboratory tool to purify and track proteins in living cells.

The technique is flexible in that an array of attachments, such as dyes, purification agents, or mimics of natural metabolic products, can be used for different purposes and biological studies. A bonus is that the process of chemically removing and attaching the chemical probes does not degrade or alter the protein in any way.

The technique is detailed in the journal

Nature Methods.

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Lynne Friedmann is a science writer based in Solana Beach.