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At least 955 records · Page 53Linked to original sources
PubMed1994

TUBIS, a fossilized retroposon in the tubulin gene cluster of Trypanosoma brucei.

The genome of Trypanosoma brucei contains many copies of TRS/ingi, a retroposon like element of about 5 kb length. One vestigial member of this family, TUBIS, is found in the tubulin gene cluster. The element has sequence homologies to reverse transcriptase. The similarity to TRS/ingi is lost after 4 kb, resulting in a 3' truncated element. The sequence following downstream shows similarities to 5' flanking regions of VSG genes.

Amino Acid Sequence↗
PubMed1982

Comparative effects of copper, cadmium and mercury on tissue glycogen of the catfish, Heteropneustes fossils (Bloch).

Copper (Cu), cadmium (Cd) and mercury (Hg) at concentrations of 12.5 mg/l, caused a decline in the glycogen level of liver, muscle, brain and kidney of Heteropneustes fossilis. A significant increase in the glycogen content of brain was caused by low concentrations (5 and 7.5 mg/l) of both Cd and Hg 5 mg/l Cu raised the kidney glycogen level, while the same dose of Hg raised liver glycogen. It is suggested that heavy metals in low concentrations act through the endocrine system, creating hormone and/or enzyme imbalance.

Animals↗
PubMed2005

Is Giardia a living fossil?

Despite enormous efforts, the patterns of the rise of eukaryotic life on Earth are not clearly defined. The ability of eukaryotes to produce energy using oxygen and sugars was a key factor in advancing life on Earth towards complex multicellular organisms. However, this was not the only way to produce energy and survive. Mitochondria probably appeared soon after the oxygen increase in the Earth's atmosphere but many microaerophilic protists require little or no oxygen to survive. New ultrastructural, biochemical and molecular phylogeny data about structures and processes involved in the generation of energy by currently known protists have forced the revision of understanding of the "tree of life".

Animals↗
PubMed2004

Isolation of nucleic acids and cultures from fossil ice and permafrost.

Owing to their constant low temperatures, glacial ice and permafrost might contain the oldest nucleic acids and microbial cells on Earth, which could prove key to reconstructing past ecosystems and for the planning of missions to other planets. However, recent claims concerning viable cells and microbial nucleic acids obtained from ice- and permafrost cores from hundreds of thousands to millions of years old are not properly authenticated and the findings could be the result of contamination. Here, we discuss the processes that restrict the long-term survival of DNA and/or RNA molecules in ice and permafrost, and highlight sources of contamination that could result in false claims. Additionally, we present a set of precautions, controls and criteria to help ensure that future cultures and sequences are authentic.

Journal Article↗
PubMed1976

Distribution of adenosine triphosphatase and thamine pyrophosphatase in the digestive system of Heteropneustes fossils.

Histochemical localization of adenosine triphosphatase and thiamine pyrophosphatase in the digestive system of the teleost fish, Heteropneustes fossilis has been studied. In the stomach, ATPase activity is observed in the mucosa, gastric glands and muscularis. The activity is stronger in the muscularis. Very weak TPPase activity is localized only in the mucosa and gastric glands. In the intestinal mucosa ATPase activity is stronger especially, along the brush border. Mild activity is also found in the connective tissue network and their nuclei, muscularis and serosa. In the posterior portion of the intestine and rectum, the localization pattern is similar to that of intestine but the activity is weaker. TPPase activity in the intestine and rectum is restricted only to the goblet shaped mucus secreting cells. In the liver, strong activity of ATPase and moderate activity of TPPase are found in the cytoplasm as well as the nuclei of the hepatic cells.

Adenosine Triphosphatases↗
PubMed2003

Is the bacterial ferrous iron transporter FeoB a living fossil?

The cytoplasmic membrane protein FeoB of Escherichia coli, Helicobacter pylori, Legionella pneumophila and Synechocystis sp. strain PCC 6803 is necessary for Fe(2+) uptake. The C-terminal part of FeoB is predicted to contain 8-12 membrane-spanning helices. The N-terminal domain shows much similarity to eukaryotic and prokaryotic G proteins and, indeed, GTPase activity is necessary for Fe(2+) transport. Four of the five characteristic conserved G protein motifs have been identified in FeoB proteins. Whether FeoB is involved directly, via its Me(2+) binding site, or indirectly in Fe(2+) transport, remains to be investigated.

Bacterial Proteins↗
PubMed1998

Mutagenic and cytotoxic effects of exhaust particulate matter of biodiesel compared to fossil diesel fuel.

The mutagenic and cytotoxic effects of diesel engine exhaust (DEE) from a modern passenger car using rapeseed oil methyl esters (RME, biodiesel) as fuel were directly compared to DEE of diesel fuel (DF) derived from petroleum. Combustion particulate matter was collected on glass fiber filters coated with polytetrafluoroethylene (PTFE) from an exhaust dilution tunnel using three different engine test cycles on a chassis dynamometer. Filters were extracted with dichloromethane in a soxhlet apparatus for 12 h. The mutagenicity of the extracts was tested in the Salmonella typhimurium/mammalian microsome plate-incorporation assay using strains TA97a, TA98, TA100, and TA102. The toxicity to the established cell line L929 (mouse lung fibroblasts) was investigated in the neutral red assay. In the tester strains TA98 and TA100 a significant increase of mutations resulted for the particle extracts of both fuels, but for DF the revertants were significantly higher compared to RME. The highest levels of revertants were observed in tests including a cold start phase. This was probably due to incomplete combustion in the cold engine and a lower conversion rate of the cold catalytic converter. Testing with activated liver S9 fraction induced a slightly lower increase of revertants in most experiments. TA97a and TA102 showed no significant enhancement of spontaneous mutations. In the FTP-75 test cycle RME extracts showed slightly higher toxic effects to the L929 cells than DF, whereas in the other tests no significant differences were observable. These results indicate a higher mutagenic potency of DEE of DF compared to RME. This is probably due to the lower content of polycyclic aromatic compounds (PAC) in RME exhaust, although the emitted masses of RME were higher in most test procedures applied in this study.

Animals↗