Clade C es el subtipo más prevalente de HIV-1 en el mundo. La estructura cristalina del núcleo de clade C gp120 es descrito por Bjorkman y colegas, en conjunto con el complejo CD4 y el receptor CD4 - inducidos por anticuerpo. El trabajo revela que el anticuerpo hace contacto con ambos, gp120 y CD4. La portada de la revista muestra una escultura de vidrio de una partícula viral realizada por el artistaLuke Jerram (http://www.lukejerram.com/projects/glass_microbiology).pp 608–613
Progress stalled on coronavirus
Lack of in-depth studies hampers efforts to identify source.
Possible infection with the MERS coronavirus, or a closely related virus, has been detected in camels.
Frank Krahmer/Getty
A year on from the first reported human case of infection with Middle
East respiratory syndrome coronavirus (MERS-CoV), the world still has
few answers to the most pressing question from a public-health
perspective: what is the source of the steady stream of new cases? Only
with this information can the outbreak be controlled.
There have so far been 114 confirmed cases of MERS-CoV infection, including 54 deaths, with another 34 suspected cases (see ‘Catching on’).
All originated in the Arabian Peninsula, with most in Saudi Arabia and
others in Jordan, Qatar and the United Arab Emirates (UAE). Imported
cases have occurred in the United Kingdom, France, Italy and Tunisia.
The virus is thought to be an animal virus that sporadically jumps to
people — there are no signs yet that it can spread easily between
humans, although limited spread between people in close contact has been
seen.
Genome-Wide Comparison of Medieval and Modern Mycobacterium leprae
Five European individuals who lived during the Middle Ages provide a look backwards at leprosy
Leprosy was endemic in Europe until the Middle Ages. Using DNA array capture, we have obtained
genome sequences of Mycobacterium leprae from skeletons of five medieval leprosy cases from the
United Kingdom, Sweden, and Denmark. In one case, the DNA was so well preserved that full de novo
assembly of the ancient bacterial genome could be achieved through shotgun sequencing alone.
The ancient M. leprae sequences were compared with those of 11 modern strains, representing
diverse genotypes and geographic origins. The comparisons revealed remarkable genomic conservation
during the past 1000 years, a European origin for leprosy in the Americas, and the presence of an
M. leprae genotype in medieval Europe now commonly associated with the Middle East. The exceptional
preservation of M. leprae biomarkers, both DNA and mycolic acids, in ancient skeletons has major
implications for palaeomicrobiology and human pathogen evolution.
Science 341, 179 (2013)
Science 341, 179 (2013)
Voyager's Not Gone Yet
La Voyager aún en la Heliosfera
Last summer, it looked like the Voyager 1
spacecraft might have finally reached its ultimate destination.
Thirty-five years
out from Earth and three times farther
from the sun than Pluto, the decrepit spacecraft reported a sharp drop
in plasma blowing
out from the sun and a sharp jump in
cosmic rays streaming in from out in the galaxy.
But three papers published online this week in Science
conclude that Voyager 1 has not left the heliosphere—the sun's magnetic
bubble inflated by its blowing plasma—and entered
interstellar space. That's because Voyager
found no accompanying switch from the magnetic field spiraling out from
the sun
to the magnetic field of interstellar
space.
Instead, Voyager
has discovered a hybrid part of the heliosphere lying between the
heliosphere proper and true interstellar
space. And nobody knows how far that
hybrid extends and when the spacecraft will actually make humankind's
first contact with
interstellar space.
Science. Volume 340, Number 6140, Issue of 28 June 2013
PLANETA ROSA
Astronomers image pink exoplanet
A magenta exoplanet 17.5 parsecs from Earth is the lowest-mass planet that has ever been directly imaged orbiting a Sun-like star outside the Solar System, NASA announced last week. The Subaru Telescope on Mauna Kea, Hawaii, took pictures of the exoplanet GJ 504b at near-infrared wavelengths with the help of adaptive optics. GJ 504b is four times more massive than Jupiter and, with a surface temperature of 237 °C, still glows pink from its fiery birth 160 million years ago. The rosy planet (pictured in an artist’s impression) orbits the star GJ 504, which can be seen with the naked eye, in the constellation Virgo. With an orbiting radius 43.5 times Earth’s distance from the Sun, GJ 504b challenges current theories of how far away from stars large planets form. The findings will be published in The Astrophysical Journal.
Diverse Crystals Account for Beetle Sheen
Not only are beetles among the most diverse group of animals on Earth, but some rival the most flamboyant birds and dazzling coral reef fish with their metallic sheens. Researchers have now traced the evolutionary history of this iridescence in one group of beetles, the weevils, and identified an unexpectedly varied assortment of complex light-altering crystals in the insects. The new work also shows that these diverse crystal architectures all share a single origin in these beetles' evolutionary past. Weevils "have developed high crystal diversity from a relatively modest tool kit," says Ainsley Seago, a systematist with the Australian National Insect Collection in Canberra, who led the work.
ORIGEN Y EVOLUCION DE LA VIDA.
NUMERO ESPECIAL MONOGRAFICO
(Hace 16 años)
Cuando platique con el celebre biologo mexicano y del mundo, Toño Lazcano
Araujo, de la posibilidad de que nos visitara Stanley Miller, aquel inquieto
estudiante graduado de la Universidad de Chicago que había logrado
convencer al Doctor Harold Urey de reproducir en una probeta las condiciones
que pudo haber tenido la atmósfera primitiva de nuestro planeta, nunca
pense en lo grato que resultaría en muchos sentidos.
En primer lugar, en esta casa de trabajo, ARMARIO, todos, especialmente Arturo Chavolla, Cuahtemoc Vite y Maria Luisa Franco me brindaron toda clase de apoyo en relación a la posibiliad de que un suplemento cultural, dedicara, nada menos que todo el número de hoy a un tema que la cultura frecuentemente relega a un segundo o tercer plano o bién ni siquiera considera como importante: La divulgación de un tema científico
En segundo lugar, cuando invité a Javier Ruíz de la Presa a escribir sobre este tema, de inmediato le pareció interesante y hasta estímulante y escribió una colaboración esplendida de la Evolución de la Vida desde “Una perspectiva filosófica”, lo cual une a estas dos partes de la Ciencia la biológica y la humanística, cosa a veces tan dificil de integrar en este fragmentado mundo posmoderno.
Después al hablar con el naturalista jaliscience y Doctor Enrique Estrada Faudon, fué tan amable, que me pareció que la empresa de hacer este número iba a lograrse; Resulta que el Doctor Estrada Faudon es uno de los personajes de las ciencias naturales que ha dado el occidente del país; su experiencia con aspecto juvenil, lo hace imprescindible cuando uno quiere conocer algun aspecto del desarrollo de la Botánica o Geografía del estado de Jalísco. Gracias al Doctor Estrada Faudón presentamos algunas ilustraciones del biólogo mexicano Alfonso L Herrera, que por los años treintas, en plena época cristera, andaba publicando en las mejores revistas francesas los últimos avances de la Biología logrados en su propio laboratorio de la colonia Santa María en la Ciudad de México y en relación con la Plasmogénia o aparición de las primeras formas vivas sobre el planeta.
Por supuesto la aparición de los textos de Miller por un lado y Lazcano por otro, ilustran de manera impecable como la vida sobre la Tierra pudo haber surgido hace unos cuatro mil millones de años y además como esas primeras formas vivas empezaron a desarrollarse, lo cual fué perfectamente captado por JIS en su celebre cartón que dedica en exclusiva a este númeto especial. Precisamente su señor padre el Ingeniero Federico Solorzano, catedrático de “Prehistoria” en el Centro Universitario de Ciencias Sociales y Humanidades, de la Universidad de Guadalajara, nos hace un estupendo recuento de las últimas fases de la evolución: La Evolución de los hominidos precursores del Homo sapiens contemporaneo, discutiendo cuales de los restos arqueológicos de hace unos cien mil años, actualmente encontrados en diversas partes del mundo, corresponde al abuelo del hombre del siglo XXI .
Por último Ulises Iñiguez Mendoza aceptó con amabilidad el reto de colaborar también en este número, desde la perspectiva del cine: Se plantea en su docta colaboración que diferentes cineastas, uno inglés y otro ruso (Kubrick y Tarkovski), de algún modo hicieron una importante incursión en el tema de este número monográfico, por medio de sus obras maestras: 2001: “Una Odisea del Espacio” y “Solaris” respectivamente, demostrando que la cultura es un todo diverso en donde la ciencia y sus ideas permean a todo el actuar humano.
Esperamos que este acontecimiento del número monográfico sea el primero de una serie de números en donde la sociedad intelectual y el ciudadano se enlacen para demostrar que el nivel del periodismo cultural no solo lo constituyen la nota roja y la política sino que también hay sed de ciencia en la comunidad de nuestra región. Enhorabuena.
PRIMER PLANETA DISTANTE AZUL
First distant planet to be seen in colour is blue
Hubble Space Telescope measures visible light from an exoplanet.
Blue gas giant.- By observing exoplanet HD 189733 b
before, during and after it disappeared behind its host star,
astronomers were able to discover that its colour is a deep blue.
(Artist's impression.)
A navy-blue world orbiting a faraway star is the first exoplanet to have its colour directly measured. Discovered in 2005, HD 189733 b is one of the best-studied
planets outside the Solar System, orbiting a star about 19 parsecs away
in the Vulpecula, or Fox, constellation. Previous efforts to observe
the planet focused on the infrared light it emits — invisible to the
human eye.
Last December, astrophysicist Tom Evans at the University
of Oxford, UK, and his colleagues used the Hubble Space Telescope to
observe the planet and its host star. Hubble's optical resolution is not
high enough to actually 'see' the planet as a dot of light separate
from its star, so instead, the telescope receives light from both
objects that mix into a single point source. To isolate the light
contribution of the planet, Evans and his colleagues waited for the
planet to move behind the star during its orbit, so that its light would
be blocked, and looked for changes in light colour.
Nature News 11 July 2013
Proof mooted for quantum uncertainty
Study confirms principle’s limits on measurement accuracy.
Werner Heisenberg’s concept of quantum uncertainty could now be on firmer ground.
INTERFOTO/Alamy
Encapsulating the strangeness of quantum mechanics is a single
mathematical expression. According to every undergraduate physics
textbook, the uncertainty principle states that it is impossible to
simultaneously know the exact position and momentum of a subatomic
particle — the more precisely one knows the particle’s position at a
given moment, the less precisely one can know the value of its momentum.
But the original version of the principle, put forward by physicist
Werner Heisenberg in 1927, couches quantum indeterminism in a different
way — as a fundamental limit to how well a detector can measure quantum
properties. Heisenberg offered no direct proof for this version of his
principle, and expressed his ideas “only informally and intuitively”,
says physicist Jos Uffink of the University of Minnesota in Minneapolis.
Now researchers say that they have a formal proof. “Our work shows that
you can’t measure something with an accuracy any better than the
fundamental quantum uncertainty,” says Paul Busch, a theoretical
physicist at the University of York, UK, who with his colleagues posted
the proof on 6 June on the arXiv preprint server1.
Not only does the work place this measurement aspect of the uncertainty
principle on solid ground — something that researchers had started to
question — but it also suggests that quantum-encrypted messages can be
transmitted securely.
Proof mooted for quantum uncertainty
FROG IN FLIGHT
Frog in flight — The photo was taken by Andres Andrade from the Center for Genomic Sciences, UNAM, Cuernavaca, Mexico, who works on how bacterial secondary metabolites can participate in the establishment of microbial communities.
RELOG CIRCADIANO LOCALIZADO EN LA ANTENA
Getting It Just Right
Sacha Vignieri
Volume 339, Number
6125, Issue of 15 March 2013
North American monarch butterflies are known
for the massive southern migrations they undertake each year. During
these migrations,
a single butterfly may fly over 2500 miles
south to the overwintering site, where it enters diapause, a
hibernation-like state.
This same butterfly will then fly
northward in the spring, where it will become reproductive before dying
and leaving the
remainder of the return trip to its
offspring. Monarchs coordinate their southward flight on the basis of a
Sun compass mediated
through circadian clocks located in the
antennae. Guerra and Reppert now show that northbound flight is mediated
by the same
Sun compass mechanism. This finding begs
the question, however, of how individuals are able to "switch" their
compasses to
fly south in the fall and north in the
spring. Exposure of fall remigrants to variations of the day length and
temperature
conditions encountered at overwintering
sites revealed that although day length has no effect on flight
direction, temperature
was able to facilitate the directional
switch. Specifically, butterflies exposed to temperatures that were too
warm did not
switch their flight directions, whereas
those exposed to appropriately cold temperatures flew north as expected.
Thus, cold
temperatures during overwintering are
necessary for the completion of the enigmatic migration. Furthermore,
warmer winters
at these sites, due to climate change, may
interfere with the monarch's migration home.
Curr. Biol. 10.1016/j.cub.2013.01.052 (2013).
The End of the Beginning for the Brain
- Books et al. Neurobiology
Replicant's end. Publicity still from Ridley Scott's Blade Runner (1982).
CREDIT: LADD COMPANY/WARNER BROS./THE KOBAL COLLECTION
Science-fiction novels and films have long popularized the notion that machines will, sooner or later, match and ultimately exceed human-level intelligence. On the way they will acquire feelings and consciousness. In the most famous such movie, Blade Runner, a replicant exclaims in the face of its imminent demise,
"I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. Time to die."
—revealing in its eloquence and poignancy its (simulated) humanity.
Science
15 February 2013:
Vol. 339
no. 6121
pp.
759-76
ROBOTICS
Tiny, winged machines
Insect-sized robots can mimic the hovering and darting of flies.
Flies
have long been admired for their aerial agility, but technical
limitations in miniaturization have hindered attempts to replicate this
in similar-sized robots. Kevin Ma and his colleagues at Harvard
University in Cambridge, Massachusetts, have invented a specialized
laser-manufacturing process that allowed them to create tiny composite
structures, including mechanical wings and flight muscles. The
researchers used the components to build 80-milligram robotic flies with
flapping frequency, wing stroke and energy use similar to that of real
flies.
The mechanical flies (pictured) were capable of controlled
flight manoeuvres and hovering in place. The work could open the door to
additional innovations in miniaturized machines.
Nature 497, 161
BAT GENOMES
Evolution of Flight and Immunity
A juvenile male Pteropus alecto (black flying fox) spreading
its wings (for adults, average wing span: ~1 meter; average weight
range: 500 to 1000 grams).
Bats, the only mammals capable of sustained
flight, are among the world's most diverse mammals and are host to
numerous deadly
viruses. Comparative genome analyses have shed
new light on the evolution of bat-specific traits, including flight and
immunity.
See page 456. Photo: Martin Asser Hansen/www.maasha.dk
Bats are the only mammals capable of sustained flight and are notorious
reservoir hosts for some of the world's most highly
pathogenic viruses, including Nipah, Hendra,
Ebola, and severe acute respiratory syndrome (SARS). To identify genetic
changes
associated with the development of bat-specific
traits, we performed whole-genome sequencing and comparative analyses of
two
distantly related species, fruit bat Pteropus alecto and insectivorous bat Myotis davidii.
We discovered an unexpected concentration of positively selected genes
in the DNA damage checkpoint and nuclear factor κB
pathways that may be related to the origin of
flight, as well as expansion and contraction of important gene families.
Comparison
of bat genomes with other mammalian species has
provided new insights into bat biology and evolution.
Science
25 January 2013:
Vol. 339
no. 6118
pp.
456-460
EL REGRESO DE TRES DINOSAURIOS
1) EL DE TITO MONTERROSO
El dinosaurio
[Minicuento. Texto completo.]
[Minicuento. Texto completo.]
Augusto Monterroso
Cuando despertó, el dinosaurio todavía estaba allí.
FIN
2) EL DE NATURE
Return of the dinosaur Mongolian researchers have finally got their hands on the Tarbosaurus bataar
fossil (pictured) that was illegally smuggled out of Mongolia and came
to auction in the United States last year. On 16 April, the team in New
York began weighing and measuring the bones of the T. bataar
specimen in preparation for customs registration and shipment back to
Mongolia, which is expected shortly after it officially becomes
Mongolian property on 6 May. The legal status of the fossil had been in
limbo since Mongolia disputed its sale for more than US$1 million at a
New York auction house last May. The 7.3-metre-long specimen is one of
the most complete tyrannosau
3) EL PRI
Arachnoscelis magnifica
Arachnoscelis magnifica, a predaceous katydid (Orthoptera:
Tettigoniidae), on a leaf in the San Lorenzo forest of Panama. This
attractive insect
is but one of the ~25,000 arthropod species
likely to live in this 6000-hectare forest, confirming the formidable
diversity
of arthropods, which appears to be 300 times
that of mammals in tropical rainforests.
DEGRADACIÓN DE LA TIERRA
Drought kills agricultural profit
Land degradation and desertification are causing huge reductions in
agricultural profits in the world’s poorest nations, according to a
report presented at the United Nations Convention to Combat
Desertification (UNCCD). The first assessment of its kind in more than
20 years calculates that Guatemala, for example, lost 24% of its
agricultural gross domestic product to environmental degradation. The
findings were presented at the UNCCD’s second scientific conference, on 9
April in Bonn, Germany. Nearly 3.7 million people in East Africa still
require food assistance after droughts in Kenya (pictured) and other
nations wiped out crops in 2011, the UNCCD says. “Desertification, land
degradation and drought are key constraints to building social and
environmental resilience, achieving global food security and delivering
meaningful poverty reduction,” said UNCCD executive secretary Luc
Gnacadja at the meeting.
NATURAL PRODUCTS EMERGENT
Fermentation rooms, at Warp Drive Bio, could open the door to natural product drug discovery
Natural compounds produced by the world’s microbes were once the go-to source of molecules for the drug industry before the chemistry dried up and big pharma went packing. Now, researchers hope that advances in genomics will bring companies back into the fold.
volume 19 | number 4 | april 2013 nature medicine
MEXICAN ARTIST: ATANASIO ECHEVERRIA
VISIBLE EMPIRE
Botanical Expeditions and visual culture in the hispanic enlightenment
From New Spain.
Mexican artist Atanasio Echeverría's watercolor of Erythrina divaricata.
Science 9 November 2012: Vol. 338 no. 6108 pp. 743-744 BOOKS ET AL.
HISTORY OF SCIENCE
Picturing Nature and Empire
Visible Empire Botanical Expeditions and Visual Culture in the Hispanic Enlightenment by Daniela Bleichmar University of Chicago Press, Chicago, 2012. 298 pp. $55, £35.50. ISBN 9780226058535.
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