What Sparked Complex Life In Ancient Oceans? Feb 26, 2008
High-resolution geochemical data from the Doushantuo Formation indicate that the early diversification of eukaryotes may have coupled with episodic oxygenation of Ediacaran oceans. (Credit: Photograph by Shuhai Xiao). (Science Daily)
New Control Mechanism For Genetic Code Translation Discovered In Bacteria Feb 20, 2008
The leader of the study, Llu;s Ribas de Pouplana, researcher at IRB Barcelona and head of the Gene Translation Laboratory, explains, "our work strengthens the theory that many of the components of the initial genetic code, established 3,500 million years ago, have matured separately between distinct branches of evolution: bacteria, archaea and eukaryotes". The origin of the genetic code is one of the issues in evolution biology in which most questions remain unanswered. (Science Daily)
Parasite Biology Clarified With New Model Feb 20, 2008
Developing new drugs for these diseases is problematical since the Apicomplexa are eukaryotes and have many of the same metabolic pathways as their animal hosts, including humans. This means many drugs that might be used to kill or damage the parasites will also harm their hosts. (Science Daily)
Sulfate assimilation in eukaryotes: fusions, relocations and lateral transfers Feb 5, 2008
In photosynthetic eukaryotes sulfate is reduced in the plastids whereas in aplastidic eukaryotes the pathway is cytosolic ... To obtain an insight into the evolution of the sulfate assimilation pathway in eukaryotes and relationships of the differently compartmentalized isoforms we determined the locations of the pathway in lineages for which this was unknown and performed detailed phylogenetic analyses of three enzymes involved in sulfate reduction: ATP sulfurylase (ATPS), adenosine... (BioMed Central)
50 years ago in microscopy Jan 23, 2008
Some experiments then suggested that bacteria have no histones and in general fewer proteins bound to their DNA. My working hypothesis at that time was thus that during interphase the DNA-plasm of eukaryotes might be organized similar to that of prokaryotes; only the condensed metaphase chromosomes would have been specific for eukaryotes ... The DNA-plasm of interphase nuclei of eukaryotes, however, turned out not to be coagulation-sensitive ... This result was suspected to be in relation to DNA... (The Scientist)
'Tree Of Life' Has Lost A Branch, According To Largest Genetic Comparison Of Higher Life Forms Ever Jan 22, 2008
It is, therefore, essential that we know the relationships between the largest groups in the great diversity of eukaryotes, he adds ... All life on Earth can be divided into two essentially different life forms eukaryotes and prokaryotes ... The eukaryotes gather their genetic material in a nucleus, while the prokaryotes (bacteria and archaea) have their genetic material floating freely in the cell. (Science Daily)
Robert Whitcomb; entomologist explored the microbial world Jan 6, 2008
"Although we may pretend to be eukaryotes, we are impostors. . . . Spiroplasma, although discovered a mere 17 years ago, may be the largest genus of any kind on earth and may contain more than a million species.". He also was deeply interested in birds, and one of his articles, which applied the ideas of island biogeography to mainland bird populations in the eastern deciduous forest, was considered a landmark study. (Boston Globe)
Checkpoint effects and telomere amplification during DNA re-replication in fission yeast Dec 22, 2007
We found that over-expressing a non-phosphorylatable form of the replication-initiation protein, Cdc18 (known as Cdc6 in other eukaryotes), drove re-replication of DNA sequences genome-wide, rather than forcing high level amplification of just a few sequences. Moderate variations in extents of re-replication generated regions spanning hundreds of kilobases that were amplified (or not) ~2-fold more (or less) than average. (BioMed Central)
“Store that fat” says new gene. Is obesity explained? Dec 21, 2007
Any time you unravel a basic process used by a huge division of life (in this case, all "eukaryotes" -- all species that contain a cell nucleus), you have done something commendable. "The discovery we made is very fundamental," says Silver. (Why Files)
Scientists seek to assess the microbial risks in the water we drink Dec 12, 2007
However, there is much we do not know about the causes and likelihood of waterborne illness, and we can and should do more to assess the risks, according to a new report, Clean Water: What is Acceptable Microbial Risk", released by the American Academy of Microbiology. In the developing world, where diarrheal illnesses claim roughly 2 million lives each year, access to clean water is a serious public health challenge, says Mark LeChevallier of American Water Works Service Company in Vorhees,... (EurekAlert!)
Pathogens use previously undescribed mechanism to sabotage host immune system Dec 8, 2007
The researchers went on to identify a previously unknown catalytic mechanism of acid-base mediated "-elimination of phosphoserine/phosphothreonine that irreversibly inactivated the kinase. Our data provide biochemical and structural evidence for specific recognition of the dual phosphorylated MAPK substrates by the OspF family of phosphothreonine lyases and explain the enzymes differential activities towards different MAPK substrates, explains Dr. Shao. Further, as phosphorylation of serine... (EurekAlert!)
Malaria Parasite In Patient Blood Finds Distinct Physiological States Dec 5, 2007
Since the malaria parasite and the baker's yeast are both single-celled eukaryotes, it is possible they may share some of the same cellular machinery and could also respond in some similar ways to their surroundings. With this unusual approach, co-senior author Regev and her colleagues were able to describe three different classes of parasites, one of which displayed features associated with a well-known form of parasite metabolism. (Science Daily)
Fossil Find Gives Clues Of Early Life Dec 4, 2007
7 billion years and show the organism coexisted with life's two other known domains, bacteria and eukaryotes. The finding. (Science Daily)
Transcription factor target prediction using multiple short expression time series from Arabidopsis thaliana Nov 19, 2007
The central role of transcription factors (TFs) in higher eukaryotes has led to much interest in deciphering transcriptional regulatory interactions. Even in the best case, experimental identification of TF target genes is error prone, and has been shown to be improved by considering additional forms of evidence such as expression data. (BioMed Central)
Thirtieth Anniversary Of Discovery Of Third Domain Of Life Oct 17, 2007
They had divided all living organisms into two broad superkingdoms, or domains: the prokaryotes, which included both the true bacteria and archaea; and eukaryotes, including all animals, plants, fungi and protists (a diverse group that includes protozoans, algae, slime molds and other organisms) ... The genetic pattern held: The rRNA signatures of the methanogens were distinct from those of eukaryotes and bacteria. (Science Daily)
Cells and Viruses Oct 15, 2007
Cellular Organisms: Prokaryotes & Eukaryotes. All living things are composed of cells that comprise the two main categories of living organisms, prokaryotes and eukaryotes ... Eukaryotes all belong to the biological domain Eukarya. (Suite101.com)
Patterns of intron gain and conservation in eukaryotic genes Oct 13, 2007
The presence of introns in protein-coding genes is a universal feature of eukaryotic genome organization, and the genes of multicellular eukaryotes, typically, contain multiple introns, a substantial fraction of which share position in distant taxa, such as plants and animals. Depending on the methods and data sets used, researchers have reached opposite conclusions on the causes of the high fraction of shared introns in orthologous genes from distant eukaryotes ... However, the distribution of... (BioMed Central)
Census Of Protein Architectures Offers New View Of History Of Life Oct 6, 2007
The folds belonging to organisms that eventually evolved into what we now call bacteria and the multicellular eukaryotes also began to lose folds, but they started downsizing their repertoires much later than the Archaea ... The eukaryotes evolution into large, multicellular bodies that could live in diverse environments relied on an extensive library of protein architectures, he said. (Science Daily)
Giardia Genome Unlocked Oct 3, 2007
But the Giardia genome is compact compared to other eukaryotes, with simplified machinery for several basic processes, such as DNA replication and RNA processing ... The authors hypothesize that Giardia diverged from other eukaryotes more than a billion years ago ... "We embarked upon this genome project because of its importance to human health and suggestions from earlier molecular analyses that Giardia represents a very early-diverging lineage in the evolutionary history of eukaryotes," Sogin... (Science Daily)
Prokaryotic and Eukaryotic Cells Oct 2, 2007
The Difference between Prokaryotes and Eukaryotes. There are only two basic types of cells, primitive prokaryotes and the more complex eukaryotes ... All cells fall into one of the two major classifications: prokaryotes or eukaryotes. (Suite101.com)
Mapping global diversity of protozoans Sep 26, 2007
This has been broadly upheld for protists (microbial eukaryotes) by most morphological and some molecular analyses. However, morphology and most previously used evolutionary markers evolve too slowly to test this important hypothesis adequately. (BioMed Central)
Synthetic memory in eukaryotes? Sep 21, 2007
The Scientist : Synthetic memory in eukaryotes ... Synthetic memory in eukaryotes ... Similar in eukaryotes have instead relied on trial and error. (The Scientist)
New mechanism discovered for DNA recombination and repair Sep 12, 2007
They have important roles in cell proliferation, genome maintenance, and genetic diversity, particularly in higher eukaryotes. For example, Rad51-deficient vertebrate cells accumulate chromosomal breaks before death. (EurekAlert!)
Bacterial genes jump to host Aug 31, 2007
Bacteria living within insects, nematodes and other eukaryotes transfer genes into their hosts more often than previously thought, according to a published online this week in Science ... The findings may also affect how researchers sequence genomes of eukaryotes, the authors suggest ... told The Scientist, "any bacterial sequences they discover may not be the result of contamination, but rather the result of gene transfers." Geneticists have long debated the extent to which bacterial genes jump... (The Scientist)
Bacterial genome found within a fly's Aug 31, 2007
DNA from mitochondria and chloroplasts cell structures thought to have evolved from specialized bacteria have also made their way into the genomes of multicellular eukaryotes (a category including plants and animals). And a worm parasite of plants has been found to contain a gene from nitrogen-fixing soil bacteria. (Nature News Service)
Ontario mine yields scientific treasures Aug 23, 2007
Scientists have suspected archaea, bacteria and eukaryotes went their separate ways around three billion years ago, but it has been hard to pin down the time of the split. "Now, we are sure the three domains of life were well separated and evolving [independently] by 2.7 billion years ago," said Kenig. (Canada.com)
Ancient Organisms Discovered In Canadian Gold Mine Aug 23, 2007
Scientists have suspected that the three known domains of life -- eukaryotes, bacteria, and archaea -- branched off and went their separate ways around three billion years ago ... Fabien Kenig, associate professor of earth and environmental sciences at the University of Illinois at Chicago, and his former doctoral student Gregory Ventura, spent nearly five years carefully analyzing the shale samples, originally to compare what they found with an earlier Australian study suggesting the presence... (Science Daily)
All eukaryotic kinases share 1 common set of substrates Aug 22, 2007
In addition, the elucidation of many kinase cascades has proved pivotal for understanding and manipulating cellular behaviour in a variety of divergent eukaryotes ... Furthermore, the results suggest the presence of a set of kinase substrates in an ancestral eukaryote that has remained unchanged in eukaryotic life, so the earliest eukaryotes may have been less primitive than generally thought. (EurekAlert!)
Muscle mass: Scientists identify novel mode of transcriptional regulation during myogenesis Aug 18, 2007
For nearly 30 years, we have assumed that the basal transcription machinery, particularly the highly conserved TBP and TFIID complex, would be invariant and universal for all cell types in eukaryotes. It seems that this simplistic model will need to be revised with significant implications for mechanisms controlling multi-cellular differentiation, explains Dr. Tjian. (EurekAlert!)
DNA Replication Behavior In Complex Organisms May Foreshadow Leaps In Genomic Discoveries Aug 18, 2007
GIS Group Leader and the corresponding author of the publication, Dr Liu Jianhua, said, "Our evidence strongly supports the stochastic model for the regulation of DNA replication in high eukaryotes (organisms whose cells are organised into complex structures by internal membranes and a cytoskeleton) such as humans. We have shown that replication efficiency can be directly determined on a genomic scale. More significantly, our study provides for a novel methodology for the analysis of replication... (Science Daily)
Chromatin Remodeling Complex Connected To DNA Damage Control Aug 11, 2007
Shen's research is conducted in yeast, but the pathways involved are conserved in all forms of life with complex cellular organization, known as eukaryotes, right on up to humans, Shen notes. Research was funded by the National Cancer Institute, the National Institute of Environmental Health Studies, the American Cancer Society, the M. D. Anderson Odyssey Fellowship and the Theodore N. Law Award. (Science Daily)
First complete eukaryotic genome Jul 12, 2007
By virtue of these attributes and others that we had discovered previously, C. merolae appears to have the simplest nuclear genome of the non-symbiotic eukaryotes. These unusually simple genomic features in the 100% complete genome sequence of C. merolae are extremely useful for further studies of eukaryotic cells. (BioMed Central)
Surprises in sea anemone genome Jul 6, 2007
According to the study, about 80% of pan-eumetazoan genes have clearly recognizable homologs in fungi, plants, or other eukaryotes. The remaining 20% are specific to eumetazoan animals. (The Scientist)
Cell Structure Jun 25, 2007
Cells are divided into two major classes, eukaryotes and prokaryotes. The difference between these two classes is that the materials making up the nucleus of eukaryotic cells are separated from the rest of the cell by the nuclear membrane, whereas in prokaryotic cells these materials are not separated. (Suite101.com)
Yeast non-coding RNA pool runs deep Jun 22, 2007
Whole genome screens in higher eukaryotes, for instance, provided evidence for a surprisingly large number of ncRNAs. To supplement these searches, we performed a computational analysis of seven yeast species and searched for new ncRNAs and RNA motifs. (BioMed Central)
Eukaryote to prokaryote gene transfer Jun 21, 2007
Horizontal or lateral transfer of genetic material between distantly related prokaryotes has been shown to play a major role in the evolution of bacterial and archaeal genomes, but exchange of genes between prokaryotes and eukaryotes is not as well understood. In particular, gene flow from eukaryotes to prokaryotes is rarely documented with strong support, which is unusual since prokaryotic genomes appear to readily accept foreign genes ... Two non-homologous forms of fructose bisphosphate... (BioMed Central)
On The Defense: Conserved Features Of Plant Innate Immunity Jun 19, 2007
"Our work is further evidence that the little plant Arabidopsis remains a very robust genetic tool for dissecting processes in multicellular eukaryotes, with relevance to the realm of human biology. To our knowledge, this is the first placement of the NTC into a known signaling pathway in any organism. We are continuing to find commonality between animal and plant innate immunity at the level of both receptors and signalling intermediates; the complex we describe, essential for plant innate... (Science Daily)
DNA breakage surprisingly rare May 30, 2007
"It's probably why, in eukaryotes, there has evolved a more complex mechanism of histones. They need to chaperone the DNA closely and not let it break.". Andrea Gawrylewski. (The Scientist)
bZIPDB : A database of regulatory information for human bZIP transcription factors May 30, 2007
Basic region-leucine zipper (bZIP) proteins are a class of transcription factors (TFs) that play diverse roles in eukaryotes. Malfunctions in these proteins lead to cancer and various other diseases. (BioMed Central)
Archaea In Hot Springs Use Ammonia For Energy: May Shed Light On Early Evolution May 26, 2007
Discovered in the late 1970s, archaea are one of the three main branches on the tree of life, with bacteria and eukaryotes such as plants and animals on the other two branches. But scientists are just now gaining a fuller understanding of what archaea do -- in an ecological sense -- to make a living. (Science Daily)
Great Bugs of Fire - Volcano Loving Bugs May 19, 2007
Unlike the better known bacteria and eukaryotes (plants and animals), many of the archaea can thrive in extreme environments like volcanic vents and acidic hot springs. They can live without sunlight or organic carbon as food, and instead survive on sulfur, hydrogen, and other materials that normal organisms can't metabolize. (FirstScience.com)
Plankton Species' Genome Analysis Yields Surprises Regarding Evolution And Global Photosynthesis May 2, 2007
At one micron it is the smallest known phytoplankton and one of the smallest of all the eukaryotes, organisms with specialized internal cell structures that include plants and animals. A teaspoon of seawater taken off the Scripps Oceanography Pier typically contains more than 100,000 eukaryotic phytoplankton, which are found throughout the world's oceans. (Science Daily)
Phylogenetic and functional analysis of the Cation Diffusion Facilitator (CDF) family: improved signature and prediction of substrate specificity Apr 23, 2007
Representative CDF members from all three kingdoms of life (Archaea, Eubacteria, Eukaryotes) were retrieved from genomic databases. Protein sequence alignment has allowed detection of a modified signature that can be used to identify new hypothetical CDF members. (BioMed Central)
Identification and characterization of insect-specific proteins by genome data analysis Apr 4, 2007
Homologs in common to Drosophila melanogaster, Anopheles gambiae, Bombyx mori, Tribolium castaneum, and Apis melifera were compared to the complete genomes of three non-insect eukaryotes (opisthokonts) Homo sapiens, Caenorhabditis elegans and Saccharomyces cerevisiae. This operation yielded 154 groups of orthologous proteins in Drosophila to be insect-specific homologs; 466 groups were determined to be common to eukaryotes (represented by three opisthokonts) ... Stress and stimulus response... (BioMed Central)
MotifCombinator: a web-based tool to search for combinations of cis-regulatory motifs Mar 23, 2007
A combination of multiple types of transcription factors and cis-regulatory elements is often required for gene expression in eukaryotes, and the combinatorial regulation confers specific gene expression to tissues or environments. To reveal the combinatorial regulation, computational methods are developed that efficiently infer combinations of cis-regulatory motifs that are important for gene expression as measured by DNA microarrays. (BioMed Central)
An Architectural Plan Of The Cell Mar 16, 2007
It has many similarities with higher eukaryotes, including multicellular organisms. Many of the insights gained into its cellular organisation are likely to apply also to mammals. (Science Daily)
Launching the Global Community Cyberinfrastructure for Advanced Marine Microbial Research and Analysis (CAMERA) UCSD, Mar. 14 Mar 15, 2007
In addition to data from the GOS Expedition, the CAMERA database includes metagenomic data from the Marine virome data collection from Forest Rohwer's group at San Diego State University, and the metagenomic data from the Hawaii Ocean Time Series Station ALOHA contributed by Ed DeLong's group at MIT. Today's release will also allow users to access or search 68 completed genomes from the 155 genomes included in the Moore Microbial Sequencing project being conducted at the JCVI. Large reference... (University of California Newswire, CA)
Millions Of New Genes, Thousands Of New Protein Families Found In Ocean Sampling Expedition Mar 15, 2007
The team also found that several protein domains (the conserved structural units in proteins) that were previously thought to exist only in one of the four kingdoms of life (bacteria, archaea, eukaryotes, viruses) have GOS examples in another kingdom ... This was unexpected because type II GS is associated more with eukaryotes, not bacteria and viruses, and not many eukaryotes are expected in the filters that were analyzed ... The researchers theorize that this could be due to lateral gene... (Science Daily)
Gene Transfer Between Species Is Surprisingly Common Mar 12, 2007
Fewer than 10 percent of eukaryotes - plants and animals - have genes acquired via horizontal gene transfer. In a second report published by Nature, two species of bacteria living together in the pink slime of an acidic California mine were found to share large groups of genes. (Science Daily)
Genes and groups of genes commonly shared between species, studies show Mar 9, 2007
Fewer than 10 percent of eukaryotes - plants and animals - have genes acquired via horizontal gene transfer. In a second report published online by Nature on March 7, two species of bacteria living together in the pink slime of an acidic California mine were found to share large groups of genes. (EurekAlert!)
A recombinase system facilitates cloning of expression cassettes in the ciliate Tetrahymena thermophila Mar 1, 2007
Tetrahymena thermophila is one of the best characterized unicellular eukaryotes and its genome is sequenced in its entirety. However, the AT-richness of the genome and an unusual codon usage cause problems in cloning and expression of the ciliate DNA. To overcome these technical hiatuses we developed a Cre-dependent recombinase system. (BioMed Central)
DNA Ends: Common Tool, Different Job Feb 22, 2007
In eukaryotes or organisms whose cells have a nucleus, this job is handled by a tripartite complex called replication protein A (RPA) ... -- Meiosis forms the basis of sexual reproduction and can only occur in eukaryotes. (Science Daily)
Biochip Allows Genes To Express Themselves Feb 20, 2007
Biochip platforms that work as artificial cells are attractive for medical diagnostics, interrogation of biological processes, and for the production of important biomolecules. However, to match the complexity of nature, the biochips need to be designed such that proteins, DNA, and other important biological components can be located in specific, spatially well-defined regions on the chips. (Science Daily)
Prediction of highly expressed genes in microbes based on chromatin accessibility Feb 13, 2007
It is well known that gene expression is dependent on chromatin structure in eukaryotes and it is likely that chromatin can play a role in bacterial gene expression as well. Here, we use a nucleosomal position preference measure of anisotropic DNA flexibility to predict highly expressed genes in microbial genomes. (BioMed Central)
Conservation of the TRAPP II-specific subunits of a Ypt/Rab exchanger complex Feb 3, 2007
The non-essential subunit, Trs65, is conserved only among many fungi and some unicellular eukaryotes. Multiple alignment analysis of each TRAPP II-specific subunit revealed conserved domains that include highly conserved amino acids. (BioMed Central)
Theoretical Modeling Brings New Understanding Of Self-Assembly Of 'Cell Skeletons' Feb 3, 2007
Eukaryotes (also spelled "eucaryotes") comprise animals. . (Science Daily)
Together, Biological Membranes Prevail Feb 3, 2007
Eukaryotes are the most structurally complex known cell type ... Eukaryotes (also spelled "eucaryotes") comprise animals. (Science Daily)
Molecular Motors And Brakes Work Together In Cells Feb 1, 2007
-- Meiosis forms the basis of sexual reproduction and can only occur in eukaryotes ... Eukaryotes are the most structurally complex known cell type ... Eukaryotes (also spelled "eucaryotes") comprise animals. (Science Daily)
Does Evolution Select For Faster Evolvers? Horizontal Gene Transfer Adds To Complexity, Speed Of Evolution Jan 30, 2007
(July 10, 2003) -- Scientists have long thought gene exchange between individuals of unrelated species to be an extremely rare event among eukaryotes -- the massive group of organisms that counts among its members. . (Science Daily)
World`s largest flower evolved from tiny blooms Jan 15, 2007
Fastest, latest news from india zeenews. com cricket, sports, business, bollywood, entertainment, lifestyle, world and science. (Zee News)
Growth of the protozoan parasite Entamoeba histolytica in 5-azacytidine has limited effects on parasite gene expression Jan 6, 2007
In higher eukaryotes DNA methylation regulates important biological functions including silencing of gene expression and protection from adverse effects of retrotransposons. In the protozoan parasite Entamoeba histolytica, a DNA methyltransferase has been identified and treatment with 5-azacytidine (5-AzaC), a potent inhibitor of DNA methyltransferase, has been reported to attenuate parasite virulence. (BioMed Central)
