rośliny-i-grzyby: Bacteria

Evidence: 70 • authority: 72

The cell is the basic structural and functional unit of all forms of life or organisms. The term comes from the Latin word cellula meaning 'small room'. A biological cell basically consists of a semipermeable cell membrane enclosing cytoplasm that contains genetic material. Most cells are only visible under a microscope. Except for highly-differentiated cell types (examples include red blood cells and gametes) most cells are capable of replication, and protein synthesis. Some types of cell are motile. Cells emerged on Earth about four billion years ago. All organisms are grouped into prokaryotes and eukaryotes. Prokaryotes are single-celled and include archaea and bacteria. Eukaryotes can b…

Evidence: 51 • authority: 92

DNA polymerase α-primase can function as a translesion DNA polymerase.. Replication of cellular chromosomes requires a primase to generate short RNA primers to initiate genomic replication. While bacterial and archaeal primase generate short RNA primers, the eukaryotic primase, Polα-primase, contains both RNA primase and DNA polymerase (Pol) subunits that function together to form a >20 base hybrid RNA-DNA primer. Interestingly, the DNA Pol1 subunit of Polα lacks a 3'-5' proofreading exonuclease, contrary to the high-fidelity normally associated with DNA replication. However, Polδ and Polε synthesize the majority of the eukaryotic genome, and both contain 3'-5' exonuclease activity for high…

Evidence: 47 • authority: 72

A prokaryote (; from Ancient Greek πρό pró, meaning 'before'; and κάρυον káruon, meaning 'nut' or 'kernel'), less commonly spelled procaryote, is a cellular organism that lacks a distinct cell nucleus or other membrane-bound organelles. In the earlier two-empire system, prokaryotes formed the empire Prokaryota; in the current three-domain system, based upon molecular phylogenetics, prokaryotes are divided into two domains Bacteria and Archaea. A third domain, Eukaryota, which consists of single- and multi-cellular organisms with nuclei, organelles and complex cellular architecture, is sometimes considered a clade under Archaea in the two-domain system. All prokaryotes are single-celled micr…

Evidence: 44 • authority: 72

Archaea ( ar-KEE-ə) is a domain of organisms. Traditionally, Archaea included only its prokaryotic members, but has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea cladistically includes eukaryotes, the term archaea (sing. archaeon ar-KEE-on; from Ancient Greek ἀρχαῖον arkhaîon 'ancient') in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially classified as bacteria, receiving the name archaebacteria (, in the Archaebacteria kingdom), but this taxonomic approach has fallen out of use. Archaeal cells have unique properties distinguishing them from Bacteria and Eukaryota,…

Evidence: 44 • authority: 72

A chromosome is a package of DNA containing part of or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their conde…

Evidence: 39 • authority: 80

Bacterial entry into eukaryotic cells

Evidence: 39 • authority: 92

Nucleosome Assembly Protein 1 in Dinoflagellate Cells Without Architectural Nucleosomes.. Nucleosome assembly protein 1 (NAP1) is highly conserved across eukaryotes, yet its biochemical function, particularly its proposed role as a histone chaperone, remains unresolved. Dinoflagellates, including Karenia brevis ( Kb ) and Crypthecodinium cohnii ( Cc ), lack architectural nucleosomes and express core histones at unusually low levels, yet retain abundant NAP1 transcripts encoding two to three distinct homologs. Confocal immunolocalization of K. brevis showed strong nuclear signals for both homologs, between chromosomes and at the nucleolus, with higher nuclear-to-cytoplasmic ratios in G 2 tha…

Evidence: 38 • authority: 80

Gold Biomineralization on Bacterial Biofilms for Leaching of Au3+ Damages Eukaryotic Cells

Evidence: 38 • authority: 72

Programmed cell death (PCD), sometimes referred to as cell suicide or cellular suicide, is the death of a cell as a result of events inside of a cell, such as apoptosis or autophagy. PCD is carried out in a biological process, which usually confers advantage during an organism's lifecycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. PCD serves fundamental functions during both plant and animal tissue development. Apoptosis and autophagy are both forms of programmed cell death. Necrosis is the death of a cell caused by external factors such as trauma or infecti…

Evidence: 38 • authority: 92

Engineering yeast chromosomal telomeres with a bacteriophage system.. All eukaryotes, including yeast, plants, animals and humans, possess linear chromosomes. The conserved eukaryotic telomere-telomerase systems, originated and evolved over 1 billion years, protect the chromosomal ends and regulate critical physiological functions through complex networks. In this study, we replace the endogenous eukaryotic telomeres in the single-chromosome yeast Saccharomyces cerevisiae with the prokaryotic telomere system TelN/tos from the Escherichia phage N15, which forms a closed hairpin structure, by interrupting the MRX/Sae2 pathway. The prokaryotic telomeres effectively protect linear chromosomal e…

Evidence: — • authority: 65