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ScienceWeek
SCIENCE-WEEK - Part 1/3
A Free Weekly Digest of the News of Science
April 17, 1998
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Mathematicians my flatter themselves that they possess new ideas
which mere human language is as yet unable to express. Let them
make the effort to express these ideas in appropriate words
without the aid of symbols, and if they succeed they will not
only lay us laymen under a lasting obligation, but, we venture to
say, they will find themselves very much enlightened during the
process, and will even be doubtful whether the ideas as expressed
in symbols had ever quite found their way out of the equations
into their minds.
-- James Clerk Maxwell
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Contents of This Issue:
Part 1:
1. Political Pressure Forces Trial of Cancer Cocktail in Italy
2. Watson Critical of Crick's Absence from British Science
3. Agricultural Genomics Proposed as 3rd Technological Revolution
4. US Women in Science Less Accepted than Women in Business
Part 2:
5. Chemist Ronald Breslow to Receive 1999 Priestley Award
6. On Linguistic Chaos in Molecular Biology
7. German Researcher Admits Fraud and Charges Academic Cover-Up
8. A Shock Wave Model for the Formation of Chondrules
9. On the Core-Mantle Boundary Layer and Deep Earth Dynamics
10. Reconstructing Quantum States of Atomic Motion
Part 3:
11. Analysis of Potassium Ion Membrane Channel Structure
12. Similar Structure of Prokaryotic vs. Eukaryotic K(+) Channels
13. On Visual Cortex Asymmetrical Lateral Dendrites
14. An Inexpensive Test for Diagnosis of Scrapie in Sheep
15. Identification of a Genetic Marker for Osteoporosis Risk
---------------------------------------------
1. POLITICAL PRESSURE FORCES TRIAL OF CANCER COCKTAIL IN ITALY
During the past 6 months, there has been considerable turmoil in
Italy concerning an 85-year-old physician named Luigi Di Bella,
with so-called Di Bellists and the right-wing party Alleanza
Nazionale united against the Italian medical establishment.
People against Di Bella are in fact now branded as "left-wing".
What the rumpus is about is a "therapeutic" cocktail sold by Di
Bella to terminal cancer patients as a miracle cure, the cocktail
containing a mixture of vitamins, minerals, and the drug somato-
statin. The drug somatostatin has been shown to have some
effectiveness with some rare neuroendocrine tumors, but it has
been rejected by the international medical community as
ineffective with other types of tumors. Di Bella, however, claims
to have cured "thousands" of patients of cancer, but he refuses
to submit any evidence of this. Administration of the cocktail by
Di Bella can apparently cost up to $6500 per month, and some
local Italian courts have ordered the government to provide the
drug free to cancer patients. The Italian Minister of Health,
Rosa Bindi, ordered Di Bella in January to submit his files of
successfully treated patients to the health ministry, but Di
Bella refused, saying the medical establishment would reject his
treatment method outright. Di Bella's supporters have also
rejected an offer by Bindi to assemble an international panel of
independent experts to help assess the Di Bella files and decide
whether there is enough basis to warrant clinical trials. Now
Minister Bindi has evidently yielded to the political pressure,
and 10 full clinical trials will be carried out as soon as
possible at a cost of US$11 million. In an unsigned editorial
last week, the journal Nature commended Bindi's "pragmatic
solution" to the problem of public ignorance of science and
medicine. One wonders, however, if the view of the journal Nature
is justified. One wonders about the "pragmatic solution"
connected with the next miracle cure in Italy or elsewhere. Are
decisions to carry out expensive clinical trials of therapies to
be made by popular clamor or by medical experts? One wonders what
US$11 million might do for the health care of children and adults
in the Spacca in Naples. One wonders what US$11 million might do
for the general medical education of the Italian public. One
wonders about the branding of scientific and medical communities
as "left-wing" or "right-wing" by political types whose goal is
not the public good but power over the public. We do not find the
Italian solution at all commendable.
QY: Philip Campbell (nature@nature.com)
EMAIL
QY: D. Agin (agin@scienceweek.com)
EMAIL
(Nature 2 Apr 98) (Science-Week 17 Apr 98)
2. WATSON CRITICAL OF CRICK'S ABSENCE FROM BRITISH SCIENCE
In an interview with a journalist, James D. Watson, co-discoverer
with Francis H.C. Crick of the structure of DNA, suggests Crick
might have had an important beneficial influence on British
science had he remained in England with administrative duties
rather than settled himself at the Salk Institute in California
to continue research. Watson has been head of the Cold Spring
Harbor Laboratory (US) since 1968. Watson and Crick shared the
Nobel Prize in Physiology and Medicine in 1962. Watson is now
completing the second volume of his autobiography, a volume that
will apparently contain a photograph of Crick dancing with an
unclothed female entertainer sent to him as a birthday surprise.
(New York Times 7 Apr 98) (Science-Week 17 Apr 98)
3. AGRICULTURAL GENOMICS PROPOSED AS 3RD TECHNOLOGICAL REVOLUTION
In an editorial in the journal Science, Philip H. Abelson
proposes that the next great revolution after the Industrial
Revolution and the computer-based revolution is already underway
and is the genomics revolution, and that the greatest ultimate
global impact of genomics will arise from the manipulation of the
DNA of plants. In the future, the world will obtain most of its
food, fuel, fiber, chemical feedstocks, and some of its
pharmaceuticals from genetically altered vegetation and trees.
Major companies such as Dow Chemical, DuPont, Monsanto, and
Novartis are spending billions of dollars annually on genetic
engineering and on acquiring stakes in genome-oriented companies.
Humans today employ the capabilities of relatively few plants.
Abelson suggests the major challenge is to explore the
opportunities inherent in the hundreds of thousands of plant
species.
QY: P.H. Abelson (science_editors@aaas.org)
EMAIL
(Science 27 Mar 98) (Science-Week 17 Apr 98)
-------------------
Related Background:
GENETIC ENGINEERING OF DISEASE-RESISTANT RICE CROPS
Genetic engineering is the general term used for recombinant DNA
technology, a set of methods for introducing foreign DNA into a
host organism. It usually but not always involves gene cloning,
and there have been some spectacular successes in this field, for
example, the production of human insulin by genetically engin-
eered bacteria, the insulin then available as a therapy for human
diabetes. One of the most exciting areas for the application of
genetic engineering is agriculture, in particular food crops,
where there is considerable and reasonable hope that genetically
engineered food crops will be of great importance in increasing
agricultural productivity in underdeveloped countries. Pamela C.
Ronald (University of California Davis, US) reviews the recent
genetic engineering of disease-resistant rice crops, and suggests
genetic engineering will be useful for changing additional
aspects of rice and other grains, including cold tolerance and
drought resistance, and that ultimately breeders and farmers will
be able to choose from a repertoire of genetically engineered
clones to increase food production in places and under conditions
where it is badly needed. QY: P. C. Ronald, Univ. Calif. Davis,
Plant Biol., (916) 752-7094 (Scientific American November 1997)
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IRISH ACTIVIST GROUP SABOTAGES GENETICALLY ENGINEERED CROP
In Ireland, an environmental activist group called the Gaelic
Earth Liberation Front has destroyed a one-acre research crop of
genetically engineered sugar beet. Under the auspices of the
Irish Government, the crop was grown by the US chemical company
Monsanto to develop a sugar beet variety resistant to a widely
used herbicide. The Gaelic Earth Liberation Front said in a
statement: "This was Ireland's first genetically engineered crop
and we hope it will be the last." But of course it will not be
the last, and one wonders if this is activism for the sake of
activism by people who know little about the environment and
even less about biology. Patricia McKenna, a politician who
represents Dublin in the European Parliament, praised the
destruction of the sugar beet crop, accusing Monsanto and the
Irish government of "playing games with the Irish environment".
And that underscores the non-triviality of these events. The neo-
Luddite rumblings that are becoming common these days are useful
to some people with political power, which means both the source
of the rumblings and the politicians who use the rumblings need
to be confronted by the scientific community. Ultimately it is
the larger community which must be persuaded one way or the
other; it is the attitude of the larger community that will
determine the fate of the neo-Luddite groups and the politicians
who use them. Concerning the science involved, what is obvious to
the scientific community is not always obvious to the community
at large, and one can only hope the scientific community will see
its responsibility to make its case to the larger community by
forceful and articulate dissemination of information. There is no
other apparent reasonable road. (Nature 9 Oct 97)
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SECRECY OF AGRICULTURAL GENOME DATABASES CRITICIZED
If there is one area where molecular genetics is of international
political relevance it is agriculture. Every country is
interested in improving its food supply, and to this end there is
much effort devoted to genetics research, particularly research
to map the genomes of plants such as corn and rice. Plant
biologist Christopher Somerville (Carnegie Institution of
Washington in Stanford, CA US) recently criticized the delays by
some countries in releasing plant genome data to the scientific
community. The laboratories slowest to release data already in
their possession are evidently in Europe, Japan, and China.
Apparently, no release from China of acquired data has yet
occurred. In the U.S., projects underway by corporate giants such
as Monsanto and DuPont have also not been eager to supply data.
The consequence is that plant molecular geneticists are deprived
of scientific information important for their own research, the
results of which are by tradition freely reported and available
to everyone. (Science 27 Jun) (Science-Week 3 Jul 97)
4. US WOMEN IN SCIENCE LESS ACCEPTED THAN WOMEN IN BUSINESS
A meeting last month at the New York Academy of Sciences (US)
focused on the past 25 years of progress for women scientists and
engineers in the US. The apparent consensus at the conference was
that the climate for women in both industry and government has
improved much faster than in academia, with the changes in
industry mostly due to a drive by industry for diversity. The
Motorola Corporation (US) now has 43 women vice-presidents. In
1996, women were 51% of the US population, 46% of the labor
force, but only 22% of scientists and engineers. Nobel Laureate
Gertrude Elion advised women in science to follow Farragut's
order: "Damn the torpedoes -- full speed ahead."
(Chem. & Eng. News 6 Apr 98) (Science-Week 17 Apr 98)
-------------------
Related Background:
WOMEN NOW SUBSTANTIAL PORTION OF ALL NEW US CHEMISTS
The latest survey of the American Chemical Society, covering
chemists and chemical engineers who graduated between July 1996
and June 1997, shows the following statistics for new women
graduates (percentage of total graduates who are women):
Chemistry Bachelor's Degree: 48.2%
Chemistry Master's Degree: 46.2%
Chemistry PhD Degree: 31.6
Chemical Engineering Bachelor's Degree: 35.4%
Chemical Engineering Master's Degree: 29.3%
Chemical Engineering PhD Degree: 22.9%
QY: Michael Heylin
edit.cen@acs.org
(Chem. & Eng. News 9 Mar 98)
-------------------
SWEDISH STUDY SHOWS SEX BIAS AFFECTS SCIENCE EMPLOYMENT
Two female Swedish scientists have published a study which
indicates that women must publish more often than men to compete
successfully for scientific jobs in Sweden. This is the first
scientific study of sex discrimination in the awarding of a
large number of research positions, and was financed by a
Swedish government grant. The researchers, Christine Wenneras
and Agnes Wold, are both from the University of Goteborg. The
journal Nature, which published the study, states that
the "results severely undermine the credibility of the
peer-review system, not just in Sweden but elsewhere in the
world. (Nature 22 May 97)
(continued in Part 2)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
SCIENCE-WEEK - Part 2/3
A Free Weekly Digest of the News of Science
April 17, 1998
Contents of Part 2:
5. Chemist Ronald Breslow to Receive 1999 Priestley Award
6. On Linguistic Chaos in Molecular Biology
7. German Researcher Admits Fraud and Charges Academic Cover-Up
8. A Shock Wave Model for the Formation of Chondrules
9. On the Core-Mantle Boundary Layer and Deep Earth Dynamics
10. Reconstructing Quantum States of Atomic Motion
----------------------------------------------------------------
5. CHEMIST RONALD BRESLOW TO RECEIVE 1999 PRIESTLEY AWARD
The American Chemical Society has announced that Ronald Breslow
(Columbia University, US) will receive the 1999 Priestley Medal
for distinguished service to chemistry. Breslow's research has
been multi-faceted, ranging from the aromaticity of simple
compounds to the chemical properties of enzymes. He group has
recently been studying cytodifferentiating agents, substances
that reestablish cell differentiation and maturation in cancer
cells. In the 1950s, he was one of the first to apply nuclear
magnetic resonance techniques to mechanistic enzymology. Trained
at Harvard University (US) under organic chemist Robert Burns
Woodward, Breslow is now 67.
(Chem. & Eng. News 6 Apr 98) (Science-Week 17 Apr 98)
6. ON LINGUISTIC CHAOS IN MOLECULAR BIOLOGY
Nomenclature anarchy in molecular biology is apparently once
again the focus of attention, although no remedies are evident.
In a recent article, Paul Smaglik writes, "Gene and protein names
often are based on the flamboyant, the descriptive, and the
intentionally obscure. For many researchers, naming their
discovery may be a rare opportunity to imbue their science with
creativity." But Lawrence Puente (University of Alberta, CA)
points out that creativity plus competition can equal confusion.
Julia A. White (University College London, UK), a member of the
Nomenclature Committee of the Human Genome Organization, says
that although the committee strives to sort out linguistic chaos,
the committee remains behind as a result of the speed and scope
of the Human Genome Project. With hundreds of thousands of genes
and proteins still to be named, molecular biology is in dire need
of nomenclature regulation.
(The Scientist 30 Mar 98) (Science-Week 17 Apr 98)
-------------------
Related Background:
MORE DISCUSSION OF ACRONYM ANARCHY IN MOLECULAR BIOLOGY
There are approximately 100,000 genes in the human genome, and
approximately 100,000 expressed proteins, the total certainly
enough to require a dictionary of names. Add to this total the
total of acronyms used to identify cell-lines, cell receptors,
metabolic pathways, carbohydrates, etc., and the dictionary would
require a second volume. In the early days of biochemistry and
molecular biology, when few genes and their expressed proteins
had been identified, everyone could more or less remember the
names of the macromolecular entities being studied by the people
in the laboratory down the hall. These days that is unlikely, and
made more unlikely by the tendency of many molecular biologists
to choose ad hoc names that are often more cute than technically
pertinent, and to obfuscate their research papers with acronyms
by the dozen in a single paper. We know of at least one instance
where an acronym for a cell-line in a paper from a group at the
US National Institutes of Health was not defined anywhere in the
paper, where telephone calls to molecular biologists produced no
one who knew what cell-line was involved, and where a query to
the authors of the paper did not produce a response for nearly
three weeks. As one scientist recently put it: "If you make your
paper difficult to read, at least no one can call you stupid." A
recent exchange of letters in the journal Nature revisits this
recurrent problem of nomenclature in molecular biology. It seems
there are indeed existing committees concerned with regulating
the nomenclature of molecular biology, but it also seems no one
pays any attention to them. Puente et al (Univ. of Alberta, CA)
refer to the present situation as "acronym anarchy". We agree. We
would add that if the in-house editors of the leading general
journals such as Science and Nature would refuse to publish these
unduly obfuscated papers, they would be doing a service to the
scientific community.
QY: L. Puente (Nature 27 Nov 97)
-------------------
A CRITICISM OF NOMENCLATURE IN MOLECULAR BIOLOGY
Nomenclature is a serious problem in all the sciences, since as
new discoveries are made, new entities identified, new concepts
formulated, new names for these things must be found so that
scientists can communicate with each other with some degree of
precision. Most sciences have nomenclature committees that meet
regularly to standardize current terminology and make decisions
about new terminology. Molecular biology, one of the most active
scientific disciplines these days, has no such constraints, and
apparently there is growing concern that the arbitrary and some-
times whimsical naming of new entities ("miranda", "prospero",
"numb", "inscrutable") in molecular biology, with the same entity
often sporting a number of names, has reached the stage of
promoting confusion and the inability of scientists to deal
efficiently with the literature. In a recent editorial critic-
izing nomenclature practices in molecular biology, the journal
Nature says, "Regrettably, molecular biologists have followed the
particle physicists' whimsy with obscurantist enthusiasm." In
particle physics, of course, we already have "quark", "strange-
ness", "charm", "color", "top", "bottom", etc., which the
editorial calls a "descent into whimsy" started by Murray Gell-
Mann in the 1960s, who evidently took the term "quark" from a
phrase in James Joyce's FINNEGAN'S WAKE. What is interesting is
that the same journal which is criticizing whimsical scientific
nomenclature is apparently quite fond of headlines involving
whimsical wordplay, puns, and metaphors when describing scient-
ific research results. If a consequence of this attention to
nomenclature will be a more rational use of language in science,
many people will no doubt be appreciative of it.
(Nature 4 Sep 97)
-------------------
PHYSICISTS ORGANIZE AGAINST IMPENETRABLE JARGON IN PHYSICS
A group of working physicists and journal editors, under the
leadership of Mitio Inokuti (Argonne National Laboratory, US) and
Ugo Fano (University of Chicago, US) has come into existence with
the objective of reforming the publication standards for papers
in physics. The problem is that physicists no longer understand
each other, their communication warped by "unexplained acronyms,
cryptic symbols, endless sentences, and monstrous graphs".
Analyzing the psychology of why this exists, Phillip Schewe
(American Institute of Physics, US) says, "You lose all your
readers, but at least you can't be accused of being an idiot.
Instead, the readers are made to feel like they're idiots." The
problem, of course, is just as severe in chemistry and biology.
(Science 15 Aug 97)
7. GERMAN RESEARCHER ADMITS FRAUD AND CHARGES ACADEMIC COVER-UP
Producing another chapter in the scientific fraud case that has
caused an apparent sensation in Germany, Marion A. Brach, one of
the accused scientists, has published a letter in the journal
Nature in which she points out the following: 1) She has
confessed to falsifying scientific papers; 2) she has resigned
her position as a full professor at the University of Lubeck; 3)
she does not believe further victimization is appropriate; 4) she
has concluded that the various German investigating commissions
met only with the intention of limiting damage to the German
academic community rather than with the intention of discovering
the full extent of culpability; 5) the German government has
reneged on its legal agreement to provide her with severance pay
following her early confession and resignation; 6) official
bodies have found it expedient to imply that she was the major or
only culprit in the affair.
QY: Marion A. Brach, c/o Walter F. Kalthoff, Pacellistr. 14,
D-80333, Muenchen, DE
(Nature 2 Apr 98) (Science-Week 17 Apr 98)
-------------------
Related Background:
MORE DEVELOPMENTS IN GERMAN SCIENTIFIC FRAUD CASE
The scientific fraud case that has been shocking the German
intellectual community these past months, and which is claimed to
be the worst case of scientific fraud in that country since 1945,
continues to be a public spectacle. The scandal involves two
German molecular biologists, Marion Brach (who has resigned as a
Professor at Lubeck University), and Friedhelm Herrmann (a sus-
pended Professor at Ulm University). Brach has admitted falsify-
ing published data while she worked under the supervision of
Herrmann at the Max Delbruck Center for Molecular Medicine a few
years ago. Herrmann claims he is only a clinician and had nothing
to do with the laboratory bench work. Herrmann is a prominent
hematologist and a leading genetic therapy researcher. The two
biologists had worked together for some time, and each received
professorships on the basis of that work. Now it has been
announced that Herrmann is suing various academic investigators
in the case for DM10 million (US5.6 million) in compensation for
damage to his career. In addition, there is now a claim by a new
investigation team that the two accused researchers also pub-
lished falsified data earlier in their careers.
(Nature 11 Sep) (Science-Week 26 Sep 97)
-------------------
AN UPROAR OVER SCIENTIFIC FRAUD IN GERMANY
The German scientific community was rocked by scandal this
spring, and the resulting repercussions are apparently not yet
complete. The brouhaha involves two German molecular biologists,
Marion Brach (recently resigned as a Professor at Lubeck
University), and Friedhelm Hermann (a suspended Professor at Ulm
University). Brach has admitted falsifying published data while
she worked under the supervision of Hermann at the Max Delbruck
Center for Molecular Medicine a few years ago. Hermann claims he
is only a clinician and had nothing to do with the laboratory
bench work. Hermann is a prominent hematologist and a leading
genetic therapy researcher. The two biologists have worked
together for some time, and each received professorships on the
basis of that work. All of that work is now being investigated,
and the German government has established a commission of
international scientific experts to discuss research standards
and the procedures for scientific oversight in German and
internationally. (Science 11 Jul 97) (Science-Week 18 Jul 97)
8. A SHOCK WAVE MODEL FOR THE FORMATION OF CHONDRULES
Chondrites are a type of stony meteorite consisting of an
agglomeration of millimeter-sized globules called chondrules, and
the are thought to be unchanged since the original condensation
out of the nebula from which the sun and solar system formed.
... ... Connelly and Love (2 installations, US) review present
ideas concerning the formation of chondrules in a process of
repeated, localized, brief (minutes to hours) melting of cold
aggregates of mineral dust in the protoplanetary nebula that was
the precursor to the solar system. Astrophysical models of
chondrule formation have been unable to explain the
petrologically diverse nature of chondrites, of which there are
many types. However, a nebular shock-wave model for chondrule
formation is consistent with many of the observed petrological
and geochemical properties of chondrules, and explains various
structural properties of the particles. Identifying the source of
the shock-wave heating is still a problem, but the author
suggests several possibilities.
QY: Harold C. Connelly Jr., California Institute of Technology
818-395-6811 (Science 3 Apr 98) (Science-Week 17 Apr 98)
9. ON THE CORE-MANTLE BOUNDARY LAYER AND DEEP EARTH DYNAMICS
Seismic studies indicate the interior of the Earth consists of
three parts: a metallic core, a dense rocky mantle, and a thin
low-density crust. The central part of the core is solid, but the
outer part of the core is evidently liquid. The mantle, the layer
of dense rock and metal oxides between the molten part of the
core and the surface, has plastic properties (i.e., it is a solid
capable of flow under pressure). ... ... Lay et al (3 authors at
2 installations, US) review recent ideas concerning the core-
mantle boundary layer and deep Earth dynamics. The Earth acquired
very early in its history its primary layered structure, which
consists of a molten metallic alloy core overlain by a thick
shell of silicates and oxides, and the region near the core-
mantle boundary surface has undoubtedly played a significant role
in both the core and mantle dynamic systems through their
subsequent 4.5 billion years of evolution. Recent seismological
work has revealed new structures in the boundary layer between
the Earth's core and mantle, and the observation are altering and
expanding perspectives of the role this region plays in both core
and mantle dynamics. The authors suggest that clear challenges
for future research in seismological, experimental, theoretical,
and computational geophysics have emerged, holding the key to
understanding both this dynamic system and geological phenomena
observed at the Earth's surface. It seems likely that the core-
mantle boundary is about to replace the transition zone between
Earth's upper and lower mantle as the region most likely to hold
the key to a large number of geophysical problems.
QY: Thorne Lay (thorne@earthsci.ucsc.edu)
EMAIL
(Nature 2 Apr 98) (Science-Week 17 Apr 98)
10. RECONSTRUCTING QUANTUM STATES OF ATOM MOTION
In quantum mechanics, the wave function of a system (Schroedinger
wave function, probability amplitude, psi function) is a function
of the coordinates of the particles of the system and of time, a
solution of the Schroedinger wave equation, and a determination
of the average result of every conceivable experiment on the
system. In general, the term "phase space" refers to an n-
dimensional space in which a point (with n coordinates)
represents a particular state of an n-variable system. The
movement of such a phase point in its phase space describes a
phase "trajectory". ... ... Leibfried et al (3 authors at 2
installations, DE US) review recent work concerning the
reconstruction of quantum states of atomic motion by means of
Wigner distributions (Wigner functions). Quantum mechanics allows
only one incomplete glimpse of a wave function, but if systems
can be identically prepared over and over, quantum equivalents of
shadows and mirrors can provide the full picture. In 1932, Eugene
Wigner presented what is now called the Wigner distribution as a
convenient mathematical construct for visualizing quantum
trajectories in phase space. The Wigner distribution retains many
of the features of a probability distribution, except that it can
be negative in some regions of phase space. The authors describe
methods for reconstructing the Wigner distribution of atomic
motion in phase space from sets of repeated measurements. They
suggest that such newly developed measurement techniques may have
abundant future applications in quantum control, quantum
computing, quantum-limited deposition techniques, analysis of
Bose-Einstein condensates of dilute gases, and the study of
quantum decoherence. QY: Dietrich Leibfried, Innsbruck
University, AT
(Physics Today April 1998) (Science-Week 17 Apr 98)
(continued in Part 3)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
SCIENCE-WEEK - Part 3/3
A Free Weekly Digest of the News of Science
April 17, 1998
Contents of Part 3:
11. Analysis of Potassium Ion Membrane Channel Structure
12. Similar Structure of Prokaryotic vs. Eukaryotic K(+) Channels
13. On Visual Cortex Asymmetrical Lateral Dendrites
14. An Inexpensive Test for Diagnosis of Scrapie in Sheep
15. Identification of a Genetic Marker for Osteoporosis Risk
----------------------------------------------------------------
11. ANALYSIS OF POTASSIUM ION MEMBRANE CHANNEL STRUCTURE
Ion channels are protein channels in cell membranes that allow
ions to pass from extracellular solution to intracellular
solution and vice versa. Most ion channels are selective,
allowing only certain ions to pass, and an individual cell has
ion channels with various ion selectivities. The selectivity of
an ion channel can be "gated", the channel effectively opened or
closed, and ion channels are said to voltage-gated or ligand-
gated, depending on how the change in selectivity is provoked.
The potassium ion channel from the prokaryotic soil bacterium
Streptomyces lividans is an integral membrane protein with
sequence similarity to all known potassium ion channels,
particularly in the pore region. ... ... Doyle et al (8 authors
at Rockefeller University, US) report an x-ray analysis (data to
3.2 angstroms) of the Streptomyces lividans potassium channel
reveals four identical subunits create an inverted cone cradling
the selectivity filter of the pore in its outer end. The narrow
selectivity filter is only 12 angstroms long, whereas the
remainder of the pore is wider and lined with hydrophobic amino
acids. The selectivity filter is apparently held open by
structural constraints to coordinate potassium ions but not
smaller sodium ions. The authors suggest the architecture of the
pore establishes the physical principles underlying selective
potassium ion conduction.
QY: Roderick MacKinnon (mackinn@rockvax.rockefeller.edu)
EMAIL
(Science 3 Apr 98) (Science-Week 17 Apr 98)
-------------------
Related Background:
NEW EVIDENCE FOR POTASSIUM CHANNEL REGULATION IN NEURON DENDRITES
The electrical activity of nerve cells in all species is
essentially controlled by the movements of ions, particularly
sodium, potassium, and calcium ions, across nerve cell membranes.
Some nerve cells, especially those in the mammalian brain, have a
complicated architecture, with extensive branching into dendrites
that receive input from other nerve cells. The broad picture of
ion movements in nerve cell axons (the output extensions of nerve
cells) is rather well-known, but the ion movements in dendrites
are less understood because of experimental difficulties. Now Dax
A. Hoffman et al (Baylor College of Medicine, TX US) have
reported a study of potassium ion regulation in a type of nerve
cell in a part of the brain called the hippocampus. The
experiments involved tissue slices of the rat brain, a standard
technique for studying mammalian brain electrical activity. At
the present time, it is axiomatic that all mammalian neurons
exhibit the same general ion dynamics, which means studies of
neurons of the rat brain can be revelatory for our understanding
of neurons of the human brain. Hoffman and his group found a high
density of transient potassium ion channels in the dendrites of
the neurons they studied. They present an analysis of how these
channels regulate the responsiveness of the studied neurons to
input from other nerve cells. This new data will need to be
considered by all neurobiologists interested in the functioning
of human brain nerve cells. (Nature 26 Jun 97)
12. SIMILAR STRUCTURE OF PROKARYOTIC VS. EUKARYOTIC K(+) CHANNELS
Toxins from scorpion venom are known to interact with potassium
ion channels in eukaryotic cell membranes. Mackinnon et al (5
authors at Rockefeller University, US) report the use of resin-
attached mutant potassium ion channels from the bacterium
Streptomyces lividans to screen scorpion venom, and the toxins
that interact with the channel were identified by mass
spectrometry. The authors suggest their results indicate that the
prokaryotic potassium ion channel, whose structure has now been
revealed, has the same pore structure as eukaryotic potassium ion
channels, and that this structural conservation, through the
application of their techniques, offers a new approach to
potassium ion channel pharmacology.
QY: Roderick MacKinnon (mackinn@rockvax.rockefeller.edu)
EMAIL
(Science 3 Apr 98) (Science-Week 17 Apr 98)
13. ON VISUAL CORTEX ASYMMETRICAL LATERAL DENDRITES
Neurons exist with an enormous variety of extension architect-
ures, but in general they have one axon (which may branch
extensively) and many dendrites leading from the cell body (which
may also branch extensively). Again, in general, axons conduct
nerve impulses away from the cell body, and dendrites conduct
various types of electrical changes toward the cell body. One of
the central problems of neurobiology is to relate the specific
architecture of specific neuron types to neuron function.
... ... David Ferster (Northwestern University, US) reviews the
work of Margaret Livingston on the function of the curiously
shaped Meynert cells in the visual cortex. Meynert cells are
large pyramidal neurons distinguished by a set of long basal
dendrites that project laterally in one direction for as much as
0.7 mm. Livingston proposes that the asymmetrical dendrites make
Meynert cells sensitive to visual motion, and in particular to
motion in one direction. Livingston's experiments involved
electrophysiological recordings from neurons in the visual cortex
of macaque monkeys. Ferster suggests that if Livingston's cells
are indeed Meynert cells or neurons with asymmetrical dendritic
projections, these cells would become one of the few types of
neurons in the cerebral cortex whose distinctive dendritic
morphology can be assigned a specific visual function.
QY: David Ferster (ferster@nwu.edu)
EMAIL
(Neuron 20:509 1998) (Nature 2 April 1998)
14. AN INEXPENSIVE TEST FOR DIAGNOSIS OF SCRAPIE IN SHEEP
Prions are a class of poorly understood proteins implicated in a
number of exotic human neurological diseases and in some common
animal neurological diseases such as sheep scrapie and bovine
spongiform encephalopathy in cattle ("mad cow disease"). Scrapie
is a fatal disease; there is no cure or treatment for scrapie,
and its transmission is not fully understood. Sheep can harbor
the disease for up to five years before they exhibit symptoms
such as trembling, incoordination, or scraping against objects.
Until now, a diagnosis of scrapie could only be confirmed by
examining the brains of dead animals. Now O'Rourke et al
(Agricultural Research Service, US) report that sheep eyelids
hold the key to an easy, relatively inexpensive test for
diagnosing scrapie. The O'Rourke research group has discovered
that the third eyelid in sheep collects prion proteins, and they
have designed a new antibody to identify prions in a sample of
eyelid tissue.
QY: Donald P. Knowles (dknowles@vetmed.wsu.edu)
EMAIL
(US Agricul. Res. Serv. 9 Apr 98) (Science-Week 17 Apr 98)
15. IDENTIFICATION OF A GENETIC MARKER FOR OSTEOPOROSIS RISK
Osteoporosis is a common disorder with a strong genetic
component, the disease characterized by reduced bone mineral
density, deterioration of the microarchitecture of bone tissue,
and increased risk of fracture. ... ... Uitterlinden et al (10
authors at 2 installations, NL UK) report an investigation of the
genetic component of osteoporosis as expressed through
polymorphisms of the gene {COLIA1}, the gene for collagen type l-
alpha-1, a bone-matrix protein. Results of the study of 1778
postmenopausal women in the Ommoord District of Rotterdam
indicate that {COLIA1} polymorphism is associated with reduced
bone density and predisposes women to osteoporotic fractures. The
authors suggest that genotyping an identified polymorphic
{COLIA1} marker (Sp1) may provide information on susceptibility
to osteoporotic fracture that could complement information gained
from bone density measurements alone.
QY: Andre G. Uitterlinden, Erasmus University Medical School,
Rotterdam, NL. (New England J. Med. 9 Apr 98)
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BOOK NOTES:
M. Begelman and M. Rees: GRAVITY'S FATAL ATTRACTION
Black Holes in the Universe
W.H. Freeman, 1998, 259p, UK22.95, paper UK15.95
A popularized account by two leading authorities on the
astrophysics of black holes.
A.C. Fabian (ed.): EVOLUTION
Society, Science and the Universe
Cambridge Univ., 1998, 185p, US24.95 UK16.95
A collection of essays by various authors: Stephen Jay Gould,
Lewis Wolpert, Jared Diamond, Richards Rogers, Tim Ingold,
Gillian Beer, Freeman Dyson, Martin Rees. A tracing of the
footprints of evolution through art and science.
D.L. Hartl and A.G. Clark: PRINCIPLES OF POPULATION GENETICS
Third Edition
W.H. Freeman, 1998, 480p, UK39.95
An introduction to the principles of genetics and statistics
relevant to population studies. The forces affecting genetic
variation; molecular and other methods used to study natural
populations.
Mark Ladd: INTRODUCTION TO PHYSICAL CHEMISTRY
Third Edition
Cambridge Univ., 1998, 533p, US100 UK65, paper US44.95 UK22.95
An undergraduate textbook. This new edition includes computer
simulation techniques and a discussion of quasicrystals.
Ulf Lagerkvist: DNA PIONEERS AND THEIR LEGACY
Yale Univ., 1998, 184p, UK15.95
An account of the origins of modern molecular biology, the lives
of pioneering scientists in the field of nucleic acid research,
the discovery of DNA. A nontechnical treatment.
G. Rapp Jr. and C.L. Hill: GEOARCHEOLOGY
The Earth-Science Approach to Archeological Interpretation
Yale Univ., 1998, 280p, UK28, paper UK15.95
Apparently the first textbook to offer an integrated approach to
geoarcheology -- the direct use of geologic concepts, methods,
and knowledge to solve archeological problems and interpret
archeological records.
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