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  lecture on the incredible rate of progress in biotechnology [32:52 minutes]

Highly recommended.

the web address for the article above is
https://www.abelard.org/news/science0801.php#biotechnology_110308

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international space station [iss], a truly international mission - the space robots

This news item has been ‘promoted’ to its own page - space robots - international space station, part of a developing section on space, science and technology.

Canadarm2, the two-armed robot known as Dextre, the Mobile Base System and the rail track. Image: CSA

the web address for the article above is
https://www.abelard.org/news/science0801.php#space_robots_iss_100308

human chimera

“One human chimera came to light when a 52-year-old woman demanded an explanation from doctors after tests showed that two of her three grown-up sons were biologically unrelated to her.

“Although the woman, "Jane", conceived them naturally with her husband, tests to see if she could donate a kidney suggested that somehow she had given birth to somebody else's children.”

“In medicine, a person composed of two genetically distinct types of cells. Human chimeras were first discovered with the advent of blood typing when it was found that some people had more than one blood type. Most of them proved to be "blood chimeras" -- non-identical twins who shared a blood supply in the uterus. Those who were not twins are thought to have blood cells from a twin that died early in gestation. Twin embryos often share a blood supply in the placenta, allowing blood stem cells to pass from one and settle in the bone marrow of the other. About 8% of non-identical twin pairs are chimeras.” [Quoted from medterms.com]

Credit: answersingenesis.org

end note

In Greek mythology, the Chimera is fire-breathing female monster with a lion’s head, a goat’s body and a serpent’s tail. Its parents were Typhon and Echidna. In due course, the Chimera was killed by Bellerophon, a Corinthian hero.

the web address for the article above is
https://www.abelard.org/news/science0801.php#human_chimera_250208

This news item has been ‘promoted’ to its own page - water cube - beijing2008: national aquatic center, part of a developing section on wondrous architecture.

The Water Cube at night, giving an idea of the building’s scale. Credit: beijing2008.cn

the web address for the article above is
https://www.abelard.org/news/science0801.php#water_cube300106

programming biological reactions, like programming computers

We can program [tell] computers to do huge calculations, we can make word processors follow series of instructions, now researchers are starting to make biological processes act according to instructions. In this case, some DNA tells other DNA to ‘walk’ along a DNA track.

“[...] long-term vision of developing a "compiler for biomolecular function" that takes as input a modular conceptual device design and provides as output a list of biomolecules that interact to implement the desired function.” [Quoted from The Pierce Lab]

“Ultimately, the development of an efficient catalytic DNA fuel delivery mechanism should enable the rational design of a completely artificial DNA walker that locomotes autonomously, allowing detailed programming of a motor protein mimic.” [Quoted from The Pierce Lab]

Right: “The diagrams depict (a) unbound walker, (b) walker attached to branch 1, (c) walker attached to branches 1 and 2, and (d) walker released from branch 1 to yield duplex waste.”

For those who are interested to a greater degree, here follows the detailed description of this walking process (note that the description is in science-speak).

“The system has four components (Table 1, which lists the DNA sequences used): a walker (W), a track (T), attachment fuel strands (A), and detachment fuel strands (D).

“The walker consists of two partially complementary oligonucleotides, with a 20-bp helix joining two single-stranded legs (each 23 bases).

“The track, constructed of six oligonucleotides, has four protruding single-stranded branches (each 20 bases) separated by 15-bp scaffold helices.

“Neighboring branches run in opposite directions, so spacing of 1.5 helical turns places all branches on the same side of the track approximately 5 nm apart [see diagram above].

“[As seen in the diagram], the walker strides along the track under the external control of A [attachment] and D [detachment] strands. An A strand specifically anchors the walker to a branch by forming helices with the corresponding leg (18-bp) and branch (17-bp).

“Single-stranded hinges adjacent to either end of these helices (underlined in Table 1) provide flexibility for adopting different conformations depending on the fuel species that are present. When both legs are bound to the track [ c) in the diagram], the trailing leg is released using a D strand that nucleates with the perfectly complementary A strand at a 10-base overhang and then undergoes a strand displacement reaction to produce duplex waste and free the walker leg for the next step [ d) in the diagram].”

end notes

1. compiler

   A compiler takes a program written in a higher level language and turns it into a series of machine code instructions.