
After a long publication struggle, two articles from two close friends have finally been published: the description of novel species Bacillus coahuilensis by my former bacteriology teacher and former owner while doing my Social Service and actually the one to blame for my adscription to the lab I work in now, René Cerritos (a.k.a. Dr. Chapultepec) in the IJSEM Journal. The other is the publication of the complete genome sequence of the very same strain in PNAS by my former schoolmate, my former Represenant in the Universitary Council and beermate Luis Alcaraz (a.k.a. The Dude). Both are the product of a weird collaboration between the CINVESTAV and LANGEBIO in Iruapuato, the Texan universities of Rice and Houston and the institutes Biotechnology and Ecology in UNAM, where I'm at.
In short:
Cuatrociénegas Valley is in a 750 m basin above sea level in North Mexico, deep in the Chihuahuan Desert and formerly a coastal region during the Jurassic. It is characterized by the presence of many oligotrophic ponds in the middle of the desert supporting large bacterial communities, appearingly from a marine origin (as shown by Souza and Desnues), that have been studied by my labgroup leaded by Valeria Souza and Luis Eguiarte (the very same place where I'm conducting my Theses). Cerritos isolated many bacilli strains from one of the widest and shallowest pond (Churince's Laguna Grande) and found many moderately halophilic species (that tolerate slightly salty envirnoments). A novel aerobic strain (m44) belonged to a group of aquatic, moderatedly halophilic species (B .marisflavi, B. aquimaris, B. vietnamensis) , and could not grow on most sugar-contaning media (uncommon for the bacilli). The team in CINVESTAV sequenced the genome (leaded by Gaby Olmedo and Luis Herrera-Estrella) and Alcaraz anotated it. He also conducted most of the sequence analises, with some help of Siefert from Rice University, Putonti from the UofH and me, during our stay in Houston a year ago. The genome turned out to be the smallest genome within bacilli with 3.35 Mbp with many mobile elements.
The most important feature of B. coahuilensis is that this is the second mexican microbial genome sequenced to date (the two bacteria genomes sequenced in Mexico are Rhizobium etli by the CCG and this), but whose sequence has been analized in the light of ecology and evolution (remember Dobzhansky's maxima?), that is, the adaptations of a formerly marine lineage to an oligotrophic lentic environment.That is, the sequence pointed towards an adaptation to growth within low-phosphorus environment: namely the presence of sulfoquinovose synthase (sdq1) that synthesises sulfolipids to replace membrane phospholipids (which constitute around 30% of the total phosphorus), never reported before outside chloroplasts and unicellular cyanobacteria. The CINVESTAV team looked into the membrane and corroborated its sulfolipid composition.
The genome also codes for a sensory bacteriorrhodopsin gene, reminiscent of its marine origin where they are very abundant (see work by Venter and Rusch). The expression analyses proved it to be constitutive and not -light dependent, suggesting it to be an adaptation to shallow-water irradiance exposure.
Analysing the enconded transmembrane importers is a good way to analyse what the organism is uptaking for the environment, that is, it's "feeding-habits". The family of Iron-Siderophore importers is overrerpresented in B. coahuilensis, a feature shared with other aquatic bacilli, suggesting that marine bacilli actively scavenge for iron. It also show a preference for the uptake of single aminoacids and not large polypeptides, with absolute requirement of 8 aa and partial of another 5, a feature shared by the aquatic, small-genome organism Minibacterium massiliensis.
This, taken together with the fact that it has the lowest number of genes involved in nitrogen cycle, together with the experimental evidence of being incapable of utilizing a wide variety of sugars, suggests that this organism is totally dependent of the rest of the community to live on, and has evolved from a primitive bacterial component of that community with specific adaptations for a novel environment.
I'm very proud of the product of this collaboration and expect to continue this way. And also very happy because from the moment of this publication on, The Dude is able to obtain its PhD!!!
Sunday, April 13, 2008
Bacillus coahuilensis : the genomical TexMex
Posted by Daemios at 2:29 PM 2 comments
Labels: genomics, research post, ResearchInEnglish, UNAM
Monday, March 31, 2008
My Geek Pride is hurt: BLOSUM matrices
BLOSUM (BLOcks of Amino Acid SUbstitution Matrix) are the canonical substitution matrices used for scoring protein sequence alignments. In essence, it calculates the relative frequencies of all aminoacids in each position within an alignment and assigned a probability to the substitution of a particular residue. BLOSUM matrices built with closely related sequences are more stringent and have high numbers (BLOSUM80) indicating the percentage similarity allowed to include a sequence in the matrix (in the latter case, all proteins share at least 80% sequence identity).
BLOSUM matrices were developed in 1992 by Henikoff and Henikoff and since then have been extensively used in all analyses involving protein sequences...
and then, here comes he "AAARRGHHHH!!!"
Styczynski et al (2008) were killing their time looking at the evolution of the BLOCKS database and found the unthinkable.... an error in the source code for the algorithm that calculates de BLOSUM matrices!!!! that means... the results obtained with the available BLOSUM matrices differ significantly from the expected algorithm from Henikoff & Henikoff... merde!
Weirdest thing of all.. when corrected and tested back for the use of the matrices in database sequence search, it turned out that the "wrong" matrices performed much better in retrieving protein homologs than the "corrected" matrices.
Fortunately, it seems that though the difference is statistically significative, it is not big. That means, we haven't fucked it up so bad.
Epilogue to the blosum...
1) 16 years of extensive usage doesn't mean it is RIGHT.
2) how come that no one, ever, in 16 years, ever noticed this difference!!! THAT is what happens with dogma... when you take anything from granted
3) messing things up is not always THAT bad...
4) I didn't understand from the article if they proposed that the matrices were corrected even if they performed worse...
5) I would expect to see a huge ocean of erratas everywhere because "when using the revised blosum matrices... our results from the past ten years have completely changed!!"
Posted by Daemios at 4:55 PM 8 comments
Labels: research post, ResearchInEnglish
Tuesday, March 04, 2008
Bound to...
Diving into my ipod, I rediscovered what I think is one of the best breaking up songs ever. I'm not in that mood now, but I keep recognizing it. So, this post goes dedicated to all those girls that actually are brave enough to say 'I'm through'... I mean, there must be some!
"I've thought about it for a while
and I've thought about that many miles
but I think it's time that I've gone away
The feelings that you had for me
have gone away it's plain to see
and it looks to me
that you're pulling away
I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away
I found it hard to say to you
that this is what I have to do
but there is no way that I'm gonna stay
there are someone many things
you need to know
and I wanna tell you before I go
but it's hard to think of just what to say
I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away
I'm sorry to leave you all alone
you're sitting silent by the phone
but we've always known there would come a day
The bus is warm and softly lit
and a hundred people are ridin' it
I guess I'm just another running away
I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away
Oh yeah, yeah"
The White Stripes, De Stijl...
Posted by Daemios at 10:03 AM 0 comments
Tuesday, January 22, 2008
Lotharingie... la breve

"Uno cree que siempre ha sido así, pero no... no todo lo es todo. Aquello era vastísimo, y aunque no todos se asumían como francos, la dominancia carolingia era indiscutible. Siempre había sucedido así, los grandes imperios se resquebrajaban hasta minúsculos territorios. Así pasó con Cárthago, el Senatus Populusque Romanus de Trajan, el Khanato de Ögedei y el Califato Umyyad... así pasaría después con la dinastía Qing, la Totius Hispaniae de los Habsburgo, el Imperio Napoleónico, el Brazil de Braganza y la Soyuz Sovetskikh... así pasará con la Rossiyskaya transcontinental, la Francia de Ultramar, el paternalismo neocolonialista de la Norteamérica intervencionista y el mayor imperio en tiempo y extensión: el United Kingdom del imperio británico.
El entonces imperio franco de Charlemagne había sido dividido por primera vez burdamente por Louis I (el primero de una veintena de luises hasta ahora) en imperios del Este y del Oeste. Lothair llevaba ya diez años defendiendo ferozmente su derecho legítimo sobre los territorios Francos. La última guerra civil (que entonces respondía a un pleito entre hermanos) culminó esa noche del 843 con el Tratado de Verodunum. Esa noche a la orilla del Meuse Lothair recordaba la figura de su abuelo, aún abatido al fondo del valle por el Juramento de Strazburg. Así nacía la Lotaringia, Lotharii regnum, bajo la tradicion divisionista hereditaria de los carolingios.
La Lotharingie sería recordada como el reino entre el Rhin y el Rhône, aunque más adecuado sería medirla entre la costa frisa del Mar del Norte a Roma. Así, con esa división entre el imperio Franco del Este y del Oeste, la Lotharingie iniciaría una larga disputa entre francos y alemanes que parece terminar apenas en la segunda mitad del siglo XX. Además resultaba ser el primer reino que no recibía su nombre del idioma que hablaban sus pobladores (Francs, Alemanii) puesto que comprendía un amalgama cultural y linguístico.
La duración del magno reino lotaringio fue ridículamente corto. Una del 855 presenciamos cómo el gran Lothair ha abdicado a la corona lotaringia para recluírse en la abadía de Prüm. Poco antes de tomar los votos, repartió el reino entre sus tres hijos. La Lotharingie queda reducida de la Frisia a la Suiza, bajo el reinado de Lothair II. Ésta divisón tampoco duraría mucho. Lothair moriría ese mismo año, Lothair II moriría en 869 sin herederos legítimos, lo que conduciría a la repartición territorial entre los hermanos de Lothair I y la consecuente desaparición del reino de Lotharingie con el Tratado de Meerssen... aunque en realidad el territorio norte se encontraba ya bajo el control vikingo danés."
La región es interesante...
más que nada, la aparición y desaparción de Las Cosas Importantísimas me recuerda también la historia de Plasmogenia... y no sin cierto temor me parece que la genómica le da un aire...
insisto, no todo lo es todo
Posted by Daemios at 10:56 PM 3 comments
Thursday, January 10, 2008
La tektonik
One of the weirdest things I saw in France... a "new" dance style á lá techno-pop that reminds me a LOT of the early 90's... the rediscovery of Michael Jackson's Moonwalker maybe? if fashion has already made a complete turn and rap/dance/moonwalker is cool again... maybe we have a tiny hope of seeing a grunge retro-moment soon?
I find it good for gymnastics... and I think it's cool to see such self-assurance in teens!
Posted by Daemios at 4:16 PM 2 comments
Sunday, December 23, 2007
Del lado de allà...
Paris nos recibio frio y obscuro. El periferico parisino resulta menos feo pero igual de tedioso para perderse. Aunque se recorre en menos tiempo.
Nota cultural sobre mi propia ignorancia: existe una diferencia entre le givre y la neige, aunque el resultado es el mismo (casi): todo se ve blanco. El primero dîcese del hielo que se encuentra TODAS las manianas sobre toda superficie congelable, el segundo es la nieve que se forma exclusivamente cuando llueve a 0°C... que por cierto no he visto aun. Todos los autos se congelan en la noche y yo soy el unico en toda Nancy que se maravilla de ello y que disfruta sin bufar (gesto predominantemente frances para expresar disgusto ligero pero incomodo) quitar con la palita de quitar hielo (porque aqui hay una cosa especial para todo) (y que Marie no tiene y por eso usa su tarjeta de credito) (bueno, quien sabe si es la suya). Asimismo, soy el unico que se detiene a tomar fotos de las fuentes congeladas (metaarte cronologico involuntario), las flores muertas por la helada, las bancas bajo el hielo y las ventanas fractalicas (y unas cacas congeladas que no me dejaron fotografiar y que de hecho lalo me habia comentado) y que se detiene a descifrar el origen etnico de cada no-blanco que se cruza en la calle. Para fumar, hace falta ser un adicto erizo nicotinico pero no friolento, porque sacar los dedos de los guantes es toda una hazania y no se puede fumar mas que en los cafes, los bares y las tabaquerias (y solo hasta el 1° de enero). Como dijo Serguei en NY: "either you drink or either you smoke, because you can't smoke indoors but you can't drink outdoors". De todos modos, pague mis 4.60 € para comprar mis Gauloises brunes-sans-filtre à la Cortâzar.
Finalmente, el tren ES la onda (mas que la Taq! aunque igual de caro), asi que unas mentadas de madre a Ernesto Zedillo por vender los Trenes Mexicanos. Nos quito el romanticismo de viajar en bola, viendo paisajes bonitos y con la oportunidad de ligar chicas guapas. Yo, encontre mi francesa.
Posted by Daemios at 12:52 PM 3 comments
Wednesday, November 21, 2007
To Metagenome or not to Metagenome
A masterpiece of science blogging was posted here (http://suicyte.wordpress.com/2007/11/20/smallest-primate-ever-discovered/), addressing the finding of primate sequences in the GOS dataset, just one of the unassesed ambiguities in metagenomics.
The post is beautifully written and made me laugh really loud. The point is that metagenomics is sometimes being overselled just in the very same way as genomics has been (see Eisen's blog for just some examples) and this leads to an skeptic counterwave.
My brief cons and pros:
a) metagenomics offers indeed the unprecedented opportunity to explore unculturable microbial diversity, which no other tool can do.
b) metagenomics is not only a technological advance like genomics was, it fits perfectly in an ecological (community/ecosystemic) theoretical background
c) no matter what everybody says, the GOS sampling has provided an incredible amount of data on previously unknown (and often unimagined) microbial diversity
d) criticisms on the amount of money spent on metagenomics seem to me like questioning the financial support on Humboldt's (or any other naturalist) voyages, which were explorative and not precisely focused on any hypothesis.
e) metagenomics is obviously error-prone, and it's biases have been poorly evaluated
f) metagenomics is much more useful in small, simple communities where a reasonable coverage can be achieved
g) metagenomics is much more useful in well known, deeply studied natural communities where it is employed to answer specific biological questions
h) metagenomics is expensive!
i) a great deal of work is still to be done on: defining parameters for comparing different samples, assessing taxonomical and functional biases, increasing assembly effectiveness and contig construction, improving functional prediction, developing tools for the analysis of such huge datasets, etc.
j) metagenomics is best when interdisciplinary, that is when it's used along with techniques and analyses from other disciplines that might provide physiological, evolutionary or ecological information
That being said, metagenomics rocks!
Rusch DB, Halpern AL, Sutton G, Heidelberg KB, Williamson S, Yooseph S, Wu D, Eisen JA, Hoffman JM, Remington K, Beeson K, Tran B, Smith H, Baden-Tillson H, Stewart C, Thorpe J, Freeman J, Andrews-Pfannkoch C, Venter JE, Li K, Kravitz S, Heidelberg JF, Utterback T, Rogers YH, Falcón LI, Souza V, Bonilla-Rosso G, Eguiarte LE, Karl DM, Sathyendranath S, Platt T, Bermingham E, Gallardo V, Tamayo-Castillo G, Ferrari MR, Strausberg RL, Nealson K, Friedman R, Frazier M, & Venter JC (2007). The Sorcerer II Global Ocean Sampling expedition: northwest Atlantic through eastern tropical Pacific. PLoS biology, 5 (3) PMID: 17355176
Posted by Daemios at 10:30 AM 1 comments
Labels: metagenomics, research post, ResearchInEnglish
Thursday, November 08, 2007
Dia de Muertos / Day of the Dead
More Day of The Dead Photos Here!
Encore, and late again, I'm posting on the Day of the Dead: an ancient mexican tradition from precolombine ages that was eventually merged by the spaniard priests with All Saints festivity. It is a very eclectic tradition with mexica and catholic elements. The original idea was to host all your deceased relatives at home on a specific day (originally in march, nowadays in November 1st and 2nd). They come back from Mictlán (the land of the dead) to visit and regain energies to continue their long journey towards their final home.It is a festivity, a respectful party where you share and enjoy with your deceased relatives while mourning and remembering them. An altar is usually set up containing several elments: cempasúchitl flowers whose scent shall guide the dead towards home; copal (copalli is the nahuatl word for incense, product of the resins of the tree Bursera bipinata lay to burn) to cleanse the room; yolk bread of dead to feed your host; water to ease their thirst; salt for purification; chairs and a petate (knit mat of palm leaves) where they can lay to rest overnight; and candles.
A set of little skulls made of sugar simbolizing a tzompantli (skull altar of glory) with the names of the deceased written of the forefront, mixed up with skulls with skulls with the name of the living relatives on their forefront are an amusing and humble reminder of the thin distinction between life and death. All the altar is adorned with thin purple (catholic color for mourning) and orange (mexica color for mouring) papers cut with death alusions.
Finally, you can't forget to include the personal belongings of your deads, which function as evidence that you stil remember your dead and also to let them use them again and remember how their life was. You also cook mole (a complex dish used in important festivities) and whatever your deceased might have liked the most, along with cigarrettes and mezcal (distilled alcoholic beverage from Agave) to party, fruits as the product of the Earth (mandarin/clementine and sugarcane) and guava, tejocote and pumpkin candy.
These are some pictures from the megaaltars set up at Zocalo (Mexico City's central plaza) and at UNAM (our OpenAccess National University hehe) and... click here for last year's entry (nothing new, just different pictures), and more photos here and here inside my picasa web albums...
Posted by Daemios at 4:10 PM 0 comments
Monday, October 15, 2007
Fallece la Dra. Anita Hoffman
El pasado 11 de octubre la comunidad científica sufrió una dolorosa pérdida al fallecer la Dra. Anita Hoffman, una de las más grandes figuras pioneras de la biología en México. La Dra. Hoffman dedicó su vida al estudio de arácnidos, posicionando el Laboratorio de Acarología de la Facultad de Ciencias de la UNAM (que lleva su nombre) como punta en el estudio de arácnidos. Por si fuera poco, la Dra. Hoffman formó a una gran parte de acarólogos y entomólogos de hoy, y produjo al menos dos libros de difusión en la Colección La Ciencia Desde México: "El Maravilloso Mundo de los Arácnidos" y "Animales Desconocidos: Relatos Acarológicos".

Tuve la oportunidad de conocer a la Dra. Hoffman durante una breve estancia que realicé hace ya una eternidad trabajando con ácaros acuáticos con mi maestro y amigo el Dr. Gerardo Rivas. Era admirable verla llegar con sus ochentaytantos al tercer piso de la facultad todavía con energía suficiente para regañar a varios. Y tras no se cuantos años de ser acaróloga, me tocó verla un día frente a una pecerita convertida en terrario mirando unos trombídidos medio fascinada. Digo, no me quedé en acarología pero sí le agarré gusto a los acaritos... que para saber un poquito más de ellos se puede consultar la página del Lab. Acarología Anita Hoffman y sus fotos ó la Colección Nacional de Ácaros en el Instituto de Biología de la UNAM.La pérdida de la Dra. Hoffman representa icónicamente el fin de una etapa, tanto para la ciencia mexicana como para mí. Que esta breve entrada sirva como muestra de respeto a Anita Hoffman como aracnóloga pionera en México.

Posted by Daemios at 10:23 AM 4 comments
Sunday, September 30, 2007
Two major recommendations
For all scientific-embedded procrastinators, two major links you should definitively check [mmmhh.. sounds like an infomercial] Thanks to LD Maldonado for these!
(ONE)
It's Doug Zongker's presentation of one of his most famous works in the AAAS sessions... It's only 4 min long and worth it!
Should you feel like reviewing his paper for further comprehension, you can find it linked here.
(I would need the hands of all my 35-members lab to count the number of presentations I've seen with less content)
(TWO)
An excellent piece of work on one of the most fascinating and often overlooked animals. Click to open
[And makes me wonder how much of a prefabricated production pipeline nowadays science really is]
Posted by Daemios at 1:08 AM 4 comments
Wednesday, September 26, 2007
Useful windows
Hehe... Well, I finally found the only hardware where windows can be acknowledged as useful... y'don't believe me? belive the Lee, or this documentary, or that Gates guy at Windows 98 presentation... or those scuba divers from Sun... eh? oh yea, Windows is for graphics... suuuure! and besides bluescreens are in the past! check new WindowsVista!!!
nah... windows sucks, just go Linux!
Original idea and actual performance courtesy of The Dude, but I took the picture!
Tomorrow I'll try to come up with something against Mac... now jus lessgo bowlin'....
Posted by Daemios at 10:14 PM 0 comments
Monday, September 24, 2007
The "breaking-up" loop...
...or the neverending story...
courtesy of exquisite Mr. Tona (damn!)...
hehehe...
I'm brave enough to post it because I've broken the loop!!!!
enjoy....
Posted by Daemios at 11:58 PM 3 comments
Saturday, September 22, 2007
Merci!
Pues en la nostalgia irapuatense situada apenitas entre la soledad del lab molecular y la nada (o la milpa para ser específicos) le entran ganas de agradecer a uno... se les extraña pero no tanto!
aún así, gracias por los paros de docencia. Que quieren, me enternece ver a edgardo a medianoche de sábado preparando la clase de recombinación para mis pupilos, así que gracias a:
Ana, Esme, Reni, Edgardo, Jules, More, Eria, Valeria y Andrea
y muchas también a Fred...
!gracias por aportar a la esquizofrenia del grupo 5081!
Saludos Irapuatenses
Posted by Daemios at 1:31 AM 2 comments
Sunday, September 09, 2007
Tuesday, September 04, 2007
Cuatrocienegas de Carranza
Well, after a mail from Jeff about Cuatrocienegas, I thought of finally writing about it here...
So, briefly Cuatrocienegas de Carranza is a small town at the middle of Cuatrocienegas Basin in the northernmost part of Mexico, inside Coahuila state. It was the homeland of Don Venustiano Carranza, a figure from the revolution famous for being president, almost achieving Veracruz independence and the killing of Emiliano Zapata.
Cuatrocienegas' Basin host one of the most hostile and attractive environment I've ever encountered. Its summer temperature can be as high as 52 C, and as low as -5 C in the winter. It is dominated by an haloxerophytic environment. Annual precipitation is less than 120 cc. Half of it is gypsum rock rich while the other half is calcite rich. It hosts many endemic species, including a cilindropuntia cactus and a desert turtle. Arguably, its main atraction is the system of surface water bodies called Pozas, that seem to date back to when pangaea opened and gave place to Tethys Sea. Hence, a strange diversity can be found: they're the home of desert fishes
which are more similar to marine fishes than to freshwater ones. They also present one of the most ancient and fascinating organisms in the world: microbialites or microbial mats and stromatolites, complex and fully functional ecosystems dominated by bacteria and archaea that deposit calcium carbonate and gypsum, giving rise to hard bodies.
Here some photos of the last field trip:
the not-so-portable molecular lab at the kitchen...
The Eguiarte-Souza Lab sunsetting at the dunes
Twin Ponds' contrasting colours, nearby Pozas Azules...
Dune, sky and cloud from Gypsum Dunes...Such a strange bunch of people woould only meet at a strange place... Jeiry from Biotechnology Institute, Rafael from UNAM's filmothequem Eugenia and Fernando from Argentina, Me from nowherespecial and Vero from Chile... all at the Gypsum Quarry..
Filming sampling at Rio Mezquites' lunar red ponds...
Posted by Daemios at 1:20 AM 1 comments
Tuesday, July 31, 2007
My Life as something else: BACALAR
Well, continuing our trip, we stayed in Chetumal, a city whit a beautiful seashore and nothing else. I expected to see a friend there but couldn't reach her. (Bety? tuve allá y no te localicé)
We sampled in Laguna Bacalar, one of the very few permanent surface water systems in the Peninsula. With shallow waters and muddy bottoms, it is supposed to have seven diferent colours, each from a different cenote whose waters fed the lagoon. Place is just great. Period.
We also sampled the (one and only) Cenote Azul, whose mouth is communicated with Bacalar. The colour is fantastic and it's more than 40 mts deep.
Some samples of what the team found: aquatic mites (I shall post on them somewhen), this is something like a huge Eylais,
we also found an amplypygii, an order of arachnids also known as "tailless whip scorpions" by anglophonics, and as "heart-spiders" or "tendarapos" by us.
and finally... an onychophor!!! from phylum Onychophora (bearing nails), also knwon as "velvet worms" or "spitting worms" because they secrete a glue from a specialized gland close to their heads. They're very rare to find and extremely poorly studied (nobody would accept a thesis on them here) this is my second most favorite animal in the world... from a time between annelids and arthropods. I'm so excited about this! I'll post a video soon. In the meantime, a link to wikipedia

Posted by Daemios at 1:55 PM 0 comments
Wednesday, July 04, 2007
My life as something else... CALAKMUL
Se murió La Suzy.
La perra más educada que he conocido, iba a la universidad y esperaba afuera. Un abrazo, Conz...
Posted by Daemios at 5:48 PM 8 comments









