Tribolium castaneum is a member of the most species-rich eukaryotic order, a powerful model organism for the study of generalized insect development, and an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved the ability to interact with a diverse chemical environment, as shown by large expansions in odorant and gustatory receptors, as well as P450 and other detoxification enzymes. Development in Tribolium is more representative of other insects than is Drosophila, a fact reflected in gene content and function. For example, Tribolium has retained more ancestral genes involved in cell–cell communication than Drosophila, some being expressed in the growth zone crucial for axial elongation in short-germ development. |
Tuesday, April 22, 2008
The model beetle and pest genome sequenced
Monday, April 21, 2008
Free UCSC Genome Browser Training
"The three and half hour introductory tutorial will cover the topics needed to effectively use this powerful, free, publicly-accessible tool, including: basic functionality of Genome Browser searching and BLAT use, Table Browser use, creating and using Custom Tracks, and an introduction to the Gene Sorter.
Participants will receive slide hand-outs, exercises, and a UCSC Genome Browser and Table Browser Quick Reference Cards."
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Friday, April 18, 2008
Some Unnatural Base Pair for DNA strings ...
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Thursday, April 17, 2008
Darwin's first draft ...
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Conference: Genomes 2008 (11 th April) - Closing Session

Uri Gophna [ about "Complexity, connectivity, and the fate of laterally acquired genes". His analysis on horizontal gene transfer using E.coli as model challenged the Complexity theory (genes coding for protein which form part of protein complex in donor genome do not tend to successfully integrate in recipient genome) and came up with Balance theory (protein coded by transferred genes integrate gradually into pre-existing protein complexes in recipient). Mark Pallen [ about "Escherchia coli: Pathogenomics of a model organism" and argued that O-island 115 is a deletion in K12 and not a insertion in O157:H7 E.coli strain. Ben Adler [ about "What can we learn from comparative genomics of Leptospira species?". He started his talk by pointing to the fact that what Leptospira might be thinking about sequencing..."you have got my gene, but you don't really know me"!
This fine conference ended with the closing talk from Frank Kunst :)
Its time to walk in the streets of Paris now ...
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Conference: Genomes 2008 (11 th April) - S8
Population phylogenomics of the E.coli species
Erick Denamur, medical faculty Xavier Bichat, Paris
- Phylogeny of complete genome within species.
- Majority of E.coli strain can be assigned to one of 4 main phylogenetic groups (A, B1, B2 and D).
- These 4 phylogenetic groups differ in their phenotypic and genotypic characteristics.
- Gene conversion doesn’t affect the tree topology.
- E.coli ancestor is close to K-12
Comparative Genomics of Legionella pneumophila and Legionells longbeachae, ttwo human pathogens that coevolved with protozoa.
Carmen Buchrieser, Pasteur Institute, Paris
- Organisms- Legionella pneumophila and Legionella longbeachae.
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Conference: Genomes 2008 (11 th April) - S7
I joined the session when Fiona Brinkman was saying that hyperthermophilic bacterias have higher number of cytoplasmic protein. Later came Alexei Savchenko who was speaking that pathogens manipulate the host signalling for their benefit (e.g. uibiquitination). He also mentioned that Toronto centre has target of getting 60 high quality pdb structure per year and also look at these for catalytic activity using enzymatic assay. For more on this session, I took the nice notes from Swati which are pasted below:
The tubercle bacilli: Molecular determinants of pathogenicity and attenuation.
- Comparison between virulent strains and strains that have lost their ability to cause disease.
- RD1 was absent in M. Bovis BCG and microti but present in virulent strains.
- RD1 codes for ESAT-6 and ESX-1.
- Biologically relevant model of ESAT-6 and its protein partner CFP-10 was generated. ESAT-6 and CFP-10 was involved in the host-pathogen interation.
- Finally it was found that PhoP/PhoR was involved in the regulation of ESAT-6 secretion.
Generating protein interaction map for pathogens using yeast two hybrid.
Russel L. Finley, Wayne State University, Detroit, USA
- Organism- Campylobacter jejuni
- Two-hybrid system used to generate a protein interaction map.
- The map includes thousand of interaction and covers 80% of C. jejuni proteins.
- This approach is used to find the protein functions, pathway structure and potential new drug target for C. jejuni.
Insights into the evolution of pathogens using improved bioinformatics approaches.
Fiona Brinkman, Simon Fraser University, Canada
- Computational methods for the predication of protein subcellular localization, predication of genomic island and identification of orthologous.
- Used VFDB (most robust curated database)
- Signature tagged mutagenesis data
- Analysed 100 pathogens and nonpathogens.
- Increase in Genome size = Increase in networks
- Genomic Island plays an important role in evolution.
- Certain offensive virulence factor associated with
Genomewide structural and biochemical annotation of uncharacterized proteins from pathogenic bacteria.
Alexei Savchenko, University of Toronto, Canada
- Selected uncharacterized proteins from pathogenic bacteria.
- How the protein purification was done?
- Used X-ray to determine protein structure.
- Designed enzymatic assays to screen purified proteins for enzymatic activity.
- Biochemical characterization of protein was determined by the application of secondary screens with natural substrate.
- The main focus of this study was to annotate effectors proteins from Shigella flexneri cause shigellosis in humans.
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Conference: Genomes 2008 (10 th April) - S6
who talked about mining metagenomes with focus on di-codon frequency and GC content, followed by a talk from Victor de Lorenzo and George Weinstock
who mentioned that error rates are pretty low for 454 data compared to Solexa and looking at the price decrease from 2 runs for 20K/genome to 2K/genome with 500b reads, 454 is going in a good direction :)
For more, check out the previous post ( http://computationalbiologynews.blogspot.com/2008/04/conference-genomes-2008-10-th-april-s5.html ) for notes from Anders.
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Conference: Genomes 2008 (10 th April) - S5
and Mariagrazia Pizza who works in the area of vaccine discovery , more specifically Serogroup B Meningococcus . Later Athanasios Typas came and talked about GIANT coli system for determining genetic interactions (12X12 plate with pixel marked borders followed by inplate normalization and central substraction, the image thus obtained can be compared across similar experiments).
Thanks to Anders for taking the below notes:
Environmental (meta)genomics
- Metagenomics of digestive tract (Dusko Ehrlich, INRA)
- 10x more cells than human body, ~1000+ species
- MetaHIT project, attempt to find genes that
- Are required for life in the gut
- Has relation to obesity or intestinal bowel disease
- Identification of COGs in current data (700M) and comparison to wetlab results. Few interesting results. (I would avoid COGs)
- Viral photosynthesis (*Odded Beja, Technion, Israel)
- Bacteriophages encode parts of photosystem II
- To maintain photosyntehsis during infection
- More destructive to host
- Viral encoded such genes cluster phylogenetically
(either using alignment or PCA analysis of nucleotide freq.)
- Interesting target for microbial ecology samples?
- Nanostructur-Initiator MS (Trent Northern)
- Applications to metabolic pathway studies in microbial communities
- Predicting Biological Function at different levels (Peer Bork)
- Reconstruction of metabolic community network from homology searches + prot. Interaction data (STRING)
- “Full of pitfalls and dependencies”
- Impressive soil sample from Mexican salt swamps
- 454 data from 10 layers!
- Mapped to consensus metabolic network (somehow)
- Comparison between layers
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Conference: Genomes 2008 (10 th April) - S4
NIMS
I missed Michael Hecker's [ http://www.microbialcellfactories.com/edboard/start.asp?id=58070 ] talk " Towards the entire proteome of gram-positive bacteria" and Amos Bairoch [ http://ca.expasy.org/people/amos.html ] talk on " UniProtKB and microbial proteomes: status and future developments". I joined just before Julian Parkhill [ http://www.sanger.ac.uk/Teams/faculty/parkhill/ ] started talking about "Variation detection in highly monomorphic bacteria using new sequencing technologies". He has pipeline setup for sequencing using Solexa and 454. The measure he used for analysis was the ratio of Non-Synonymous to Synonymous mutations with S.typhi and paratyphi as an example. This interesting talk was followed by another very interesting talk from highly energetic Trent Northen [ http://masspec.scripps.edu/personnel/show_currentemployees.php?employee_ID=9 ]. He talked about NIMS chip [ http://masspec.scripps.edu/research/nims/create.php ] for "Metabolomic and Enzymatic Assays". With publications in PNAS [ http://www.pnas.org/cgi/content/abstract/105/10/3678 ] and Nature [ http://www.nature.com/nature/journal/v449/n7165/abs/nature06195.html ], it was pretty interesting to see how much one can get out from a drop of blood of a post-doc!
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Friday, April 11, 2008
Conference: Genomes 2008 (9 th April) - S2 and S3
Below are notes I shamelessly copied from Anders's ( http://ranzensama.blogspot.com/ ) slides!
Host - Microorganism interactions
- Molecular causes of pathogenicity
- Most presentations focused on one particular pathogen
- Salmonella, Xanthomonas, Vibrio cholerae, E. coli, Pseudomonas, Bartonella, Photorabdus
- Comparisons between pathogen and non-pathogen strains (often requiring HT sequencing of strains)
- Sequence analysis
- pathogenicity islands function preddiction
- genes required for host entry and colonisation
- Biological assays (nutrient assay, knock-out, RNAi, Chip-chip, proteomics, microarray data, RVA insect in-vivo )
- Metabolic reconstruction from assay and sequence data
- Some HT sequencing results:
- Genes in path. Islands often poorly understood. Many act as TFs on pathogen or host, changing gene expression patterns
- Nice study from Stephen Lory (Harvard) on model for gene reduction and gain for wild-type -> pathogen (acute or chronic) through symbiont interactions and HT
- Large scale strain comparisons revealed a number of pathogen genes shared by all virulent strains (Septemic E. coli: E.Z. Ron, Tel Aviv Uni.; Bartonella: Dehio, Schuster, et al)
Session 2: Host - Microorganism Interactions: b) Symbionts, Commensals
Session 3: Host Genomics and Vaccines
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Conference: Genomes 2008 (9 th April) - Company Presentations
454
Solexa / Illumina
SOLiD
Newbler
Nebulization
N50
This session was about latest commercially available high throughput sequencing solutions available. These can be categorized as:
A. Reversible terminator methods
1. Solexa->Illumina [ http://www.illumina.com/ ]
Add, block, detect, unblock
2. Helicos [ http://www.helicosbio.com/ ]
Skips amplification
3. 454 LS -> Roche [ http://www.454.com/ ]
Pyrophosphates, Luciferin
(454 uses somewhat amazing Newbler assembler for doing its assembly)
B. Sequencing by ligation/hybridization
1. SOLiD [ http://solid.appliedbiosystems.com/ ], polony method
fixed length oligonucleotide hybridization
Some more on how 454 has incorporated paired-end reads:
1. Tag the ends (biotin?) of the read
2. Break with EcoR1
3. Circularize
4. Locate the tags and chop of 20 bases around it
These will be the paired end reads for the orientation of the contig
We could have nebulized (fancy name for shearing in nitrogen) the output of step 3 and sequence the whole thing as well.
Quality of assembly can be assessed with the N50 score, which is the size of the contig above which we have coverage of the 50% of the genome.
Later Andreas Tauch talked about 454 sequencing of 2 Corynebacterium (used a lot for mass production of various amino acids). He followed the path of nebulizing as well as generating large insert clone phosmids for the scaffold.
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Conference: Genomes 2008 (9 th April) - S1(p2)
RNAi
Systems biology
Type 3 secretion systems
Complexity Vs Balance
GFP
2-D DIGE
Ok, now coming back to the session, Day 2:
Dr. Eliora Ron [ http://www.tau.ac.il/lifesci/departments/biotech/members/ron/ron.html ] talked about "Systemic E. coli infections – what can we predict from genomics?". She pointed out that Colisepticemia accounts for ~80% of hospital acquired infections (nosocomial?). She used the word "Genomically Dead" in her talk which I was not able to understand ... I guess I needed more Tea!
Dr. Stephen Lory [ http://micro.med.harvard.edu/faculty/lory.html ] gave "Insights into the evolution of virulence in Pseudomonas aeruginosa". He said that size of genome decreases as bacterial pathogen become Parasites while it increases as they become Free-Living (need to carry more function instead of being free-loaders!).
Dr. Roland Brosch [ http://www.pasteur.fr/recherche/unites/Lgmb/ ] talked about "The tubercle bacilli : Molecular determinants of pathogenicity and attenuation". He pointed that RD1 is missing from M.microti [ http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=128332 ]. and finally the session closed with Dr. Christoph Dehio [ http://www.biozentrum.unibas.ch/dehio/index.html ] talk on "Comparative and functional genomic analysis of Bartonella identifies type iv secretion systems as host adaptability factors".
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Conference: Genomes 2008 (9 th April) - S1
Dr. Ulla Bonas talked about how the "phytopathogen Xanthomonas manipulates the host". She talked about Type 3 secretion system [ http://www.pnas.org/cgi/content/full/100/6/3027 ] which are difficult to see in EM (thin structure and thick slides) and using http://en.wikipedia.org/wiki/Green_fluorescent_protein for nuclear localization of ~20 effector molecules.
Dr. Andrew Camilli [ http://www.tufts.edu/sackler/facultyIntros/camilliA.html ] talked about "Genetic Analysis of the Transmissible State of Vibrio cholerae". He pointed that chemical analysis of sample of water from Pond in Dhaka and Boston showed that they are same!
Dr. Thomas Meyer [ http://www.mpiib-berlin.mpg.de/research/molecular.htm ] talked about "Systematic dissection of host cell function during infection" bring to focus that RNAi technique brought Noble prize to its discoveres within 8 yrs of its discovery [ http://nobelprize.org/nobel_prizes/medicine/laureates/2006/adv.html ].
Dr. Sigrid De Keersmaecker talked about "Towards systems biology, the Salmonella typhimurium luxs/ai-2 related pathway as a case study". She brought to attention the Quorum Sensing [ http://en.wikipedia.org/wiki/Quorum_sensing ]. Data from Microarray [ http://en.wikipedia.org/wiki/DNA_microarray ], 2D Digest (DIGE) [ http://www5.gelifesciences.com/aptrix/upp01077.nsf/content/2d_electrophoresis~new_to_2d_dige ] and ChIP-chip [ http://en.wikipedia.org/wiki/ChIP-on-chip ] giving insights into expression, transciptome and proteome respectively was used for analysis.
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Wednesday, April 9, 2008
Conference: Genomes 2008
It started with talk from Martin J. Blaser talk who pointed that we are losing H.pylori from the gastric ecology (the H. pylori negative people have altered gastric environment)! This is sad because it is actually helpful to have H.pylori in early life. He pointed out that may be in future doctors will be giving H.pylori supplements to the kids! Then Pascale Cossart talked about Listeria monocytogenes as model organism to study RNA world.
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Tuesday, April 1, 2008
A Biological analysis of a radio
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Few lines from the article:
"seek advice from David Papermaster (currently at the University of Connecticut), who I knew to be a person with pronounced common sense" [ I thought David Papermaster was a fictitious name, but it turned out that he is a Harvard grad and a Professor of Neuroscience @ uchc.edu , http://216.239.59.104/search?q=cache:NC36yXMMNzUJ:grad.uchc.edu/phdfaculty/papermaster.html+David+Papermaster&hl=en&ct=clnk&cd=1&client=firefox-a ]
"At some point, David said, the field reaches a stage at which models, that seemed so complete, fall apart, predictions that were considered so obvious are found to be wrong, and attempts to develop wonder drugs largely fail"
"At this stage, the Chinese saying that it is difficult to find a black cat in a dark room, especially if there is no cat, comes to mind too often"
"Conceptually, a radio functions similarly to a signal transduction pathway in that both convert a signal from one form into another (a radio converts electromagnetic waves into sound waves)" [Author applied experimental biology approach to fix a broken Russian radio]
"First, we would secure funds to obtain a large supply of identical functioning radios in order to dissect and compare them to the one that is broken. We would eventually find how to open the radios and will find objects of various shape, color, and size"
"Although removing some components will have only an attenuating effect, a lucky postdoc will accidentally find a wire whose deficiency will stop the music completely. The jubilant fellow will name the wire Serendipitously Recovered Component (Src) and then find that Src is required because it is the only link between a long extendable object and the rest of the radio. The object will be appropriately named the Most Important Component (Mic) of the radio."
"Moreover, the graduate student would convincingly demonstrate that Mic is not required for the radio to work, and will suitably name his object the Really Important Component (Ric)."
"The fight will continue until a smart postdoctoral fellow will discover a switch, whose state determines whether Mic or Ric is required for playing music. Naturally, the switch will become the Undoubtedly Most Important Component (U-Mic)."
"The idea that one can investigate a component by cutting its connections to other components one at a time or in a combination (“alanine scan mutagenesis”) will produce a wealth of information on the role of the connections."
"Eventually, all components will be cataloged, connections between them will be described, and the consequences of removing each component or their combinations will be documented."
"However, if the radio has tunable components, such as those found in my old radio and in all live cells and organisms, the outcome will not be so promising. Indeed, the radio may not work because several components are not tuned properly, which is not reflected in their appearance or their connections."
"Yet, we know with near certainty that an engineer, or even a trained repairman could fix the radio. What makes the difference? I think it is the languages that these two groups use"
"Indeed, even though the impotence of purely experimental approaches might be a bit exaggerated in my radio metaphor, it is common knowledge that the human brain can keep track of only so many variables. It is also common experience that once the number of components in a system reaches a certain threshold, understanding the system without formal analytical tools requires geniuses, who are so rare even outside biology."
"In biology, we use several arguments to convince ourselves that problems that require calculus can be solved with arithmetic if one tries hard enough and does another series of experiments."
"One of these arguments postulates that the cell is too complex to use engineering approaches. I disagree with this argument for two reasons. First, the radio analogy suggests that an approach that is inefficient in analyzing a simple system is unlikely to be more useful if the system is more complex. Second, the complexity is a term that is inversely related to the degree of understanding. Indeed, the insides of even my simple radio would overwhelm an average biologist (this notion has been proven experimentally), but would be an open book to an engineer."
"A related argument is that engineering approaches are not applicable to cells because these little wonders are fundamentally different from objects studied by engineers. What is so special about cells is not usually specified, but it is implied that real biologists feel the difference. I consider this argument as a sign of what I call the urea syndrome because of the shock that the scientific community had two hundred years ago after learning that urea can be synthesized by a chemist from inorganic materials."
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Gisele [ http://www.ii.uib.no/~gisle/ ] shared another article in the similar spirit from Von Heijne, G. (1999), "A Day in the Life of Dr K. or How I Learned to Stop Worrying and Love Lysozyme: a tragedy in six acts" [ http://skirball.med.nyu.edu/research/sb/PSB03/Week6/VonHeijne.pdf ].
I have been bumping into many articles which reflect that specialists who are not satisfied the way their subject is being taught, another example is "A Mathematician's Lament by Paul Lockhart" [ http://randomthoughtsofani.blogspot.com/2008/04/mathematician-lament-by-paul-lockhart.html ].
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