about one year ago, i took part in a laboratory class where we learned various methods related to artificial plant reproduction.
one of the exercises was to create meristem cultures from a carnation plant (dianthus sp.), under sterile conditions.

from each shoot of the plant, we removed the developing leaves on the tip, almost down to the meristem (the few primary cells that constantly divide into more cells). we stopped the exraction at the smallest primordial leaves, placed the tiny piece of plant material on culture medium (in test tubes, under sterile conditions), added a cap to the tube, and sealed it with parafilm.
the following weeks, it was positioned beneath a daylight lamp, and after the experiment was finished, i asked if i could take one specimen home with me.

considering that it’s an almost completely closed system, i didn’t expect little william the carnation to last this long: the plant grew and grew until it reached the top, and i’ve just recently placed it upside down, so that it could grow “upwards” again.

two notes:
most people don’t consider that, in darkness, plants need to “breathe” just as animals do (as in: use O₂ and release CO₂), so the gas contents are probably still OK, if only limited. (also, i’m assuming that parafilm isn’t able to stop slow diffusion of gas molecules completely.)

supposedly getting low on fresh nutrients, the plant seems to have given up on the lower leaves so that it could develop new ones. the old, withered leaves do not decompose since there aren’t any microorganisms in the system.

photos: sterile plant culture

scientists say they’ve found and studied a complete fossil of a primate that is likely to be an early ancestor of the human species. this exciting finding may be an important “snapshot” from the time when humans, apes and monkeys diverged from the other primates such as lemurs.

a brand-new documentary, titled “the link” is set to air soon in the US, UK, norway and germany. a trailer and air dates are presented at revealingthelink.com.

Early Primate Provides Evolution Clues
Scientists say a 47-million-year-old fossil found in Germany may be a key link to explaining the evolution of early primates and, perhaps, telling them about developments that led to modern human beings.
The fossil, of a young female that probably resembled a modern-day lemur, is described as “the most complete primate fossil ever found.” It is small — its body is about the size of a raccoon — but it has characteristics found in later primates and in humans.
(…)
It has, among other things, opposable thumbs, similar to humans’ and unlike those found on other modern mammals. It has fingernails instead of claws. And by examining the structure of its hind legs (one of which is partly missing), scientists say they can see evidence of evolutionary changes that would eventually lead to primates standing upright.
(…)
“She is a transitional species showing characteristics from both the non-human (prosimians and lemurs) and human (anthropoids, monkeys, apes and man) evolutionary lines,” said the producers in a statement reviewed by the authors of the PLoS One paper.

source: abcnews.go.com

the full, scientific publication is available at www.plosone.org. it includes stunning pictures, x-rays and CTs.
here’s part of the paper’s conclusion:

Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype.

update: just found a short excerpt of the documentary from sky-news:

someone once told me, that buddhism says “once a year, you should do something you’ve never done before”.
i’ve had so many different things inside my nose lately that i think that counts for 2009.

some time ago, i discovered two fairly large masses in my nostrils.
searching for information on the internet returned lots of websites that were talking about either nasal haematoma (see photo quiz of the aafp, pictures at meduweb) or haemangioma (e.g. blog post and corresponding picture).
it wasn’t likely to be a haematoma because that is usually caused by being hit on your nose (which i hadn’t been), and the “balloons” in these pictures originated in the septum, while mine seemed to originate on the opposite side.. i didn’t know about the tumours, though.

i was relieved to hear my ENT doctor tell me that i just had very large turbinates (or nasal conchae). turns out this is why my nose had been more or less constantly congested for several years.

in terms of treatment, i had two choices:
an operation which would include a correction of the turbinates and septum, several days in a hospital, and quite some time to fully heal.
…and…
a procedure called “coblation conchotomy”, where radiofrequency is used to destroy parts of the tissue. the resulting scar tissue would then contract (as typical for scar tissue), reducing the turbinates’ size.

coblation only requires local anaesthesia, takes about 30 minutes alltogether, and is, generally, a pretty fascinating technique:
a tiny halo of reactive plasm is formed around the instrument’s tip, which makes it possible to “cut” molecular compounds in a very limited area without even getting hotter than 40-70 degrees celcius. this way, contiguous tissues stay unharmed.
there are some pretty computer animations.

there’s a video demonstration of the technique on youtube – supposedly intended to calm down possible patients. not sure it fulfills its purpose:

this narrator strongly reminded me of craig tucker from southpark – both in his way of speaking, and the blocked-nose sound of his voice.
 

update 2009-04-11: it’s been just over a month now, and i’ve recently had my last of 3 (4?) checkups. during the past weeks, i simply applied a salve to my nostrils, and in intervals of 7, 7, 14 and 14 days, my ENT doctor cleaned out the canals using something like a tiny vacuum cleaner. it’s healing well, i can breathe freely¹ and i can totally recommend the procedure.

related posts:

1. sterile plant culture

today is his 200th birthday, and the 150 year anniversary of that famous book that revolutionized the entire field of biology.

i’d like to take the opportunity to include a few quotes from the book:

it is a truly wonderful fact that all animals and all plants throughout all time and space should be related to each other in group subordinate to group, namely varieties of the same species most closely related together, (…) species of distinct genera much less closely related, and genera related in different degrees, forming sub-families, families, orders, sub-classes and classes.

(…) and as modern geology has almost banished such views as the excavation of a great valley by a single diluvial wave, so will natural selection, if it be a true principle, banish the belief of the continued creation of new organic beings, or of any great and sudden modification in their structure.

nevertheless so profound is our ignorance, and so high our presumption, that we marvel when we hear of the extinction of an organic being; and as we do not see the cause, we invoke cataclysms to desolate the world, or invent laws on the duration of the forms of life!

light will be thrown on the origin of man and his history.

it is amazing to see that 150 years later, almost every aspect of his theory is still considered to be coherent.

related posts:

1. frog spawn video in the natural history museum of neuchatel, switzerland

“frogs are a good example of evolution seeing as it only take a month or 2 for them to grow”

ontogeny (the development of an individual organism) may be a glimpse into the evolutionary history of a species, but on the other hand, evolution has nothing to with one soft, translucent piece of frog spawn developing into a tadpole.
while evolution is a shift in genetic information during hundreds or thousands of generations, a tadpole growing legs is just part of its existing genetic programme.

i think if people actually knew what the theory of evolution is all about, there wouldn’t be half as much agitation against it.

please contact me if you are interested in using them.

here’s one of the numerous animations:

it shows part of a leaf of arabidopsis thaliana, that was genetically modified in a way that makes certain structure molecules within the cell walls visible.

to be more specific, the sequences of the green fluorescent protein (GFP, originally a gene of the crystal jellyfish, aequorea victoria) and a corresponding microtubule binding domain were inserted into the plant’s DNA, so that the cell walls would emit green light when exposed to light of a particular frequency (not all cells actually produced these molecules).
autofluorescense of chloroplasts is displayed in red.

using the CLSM, about 20 images were recorded at different levels of the leaf. these layers were then rendered in an animation that highlights its tridimensionality.

the image width equals 150 μm, that’s approx. 1/7th of a millimeter.