the protozoan intestinal parasite cryptosporidium commonly infects cattle throughout the world and iran. the present study was undertaken to determine the abundance and associated risk factors of cryptosporidium infection in cattle herds of northwestern iran. a total number of 246 fecal samples from 138 (56.1%) diarrheic (d) and 108 (43.9%) non-diarrheic (nd) cattle were randomly collected and ...

Ribosome biogenesis occurs successively in the nucleolus, nucleoplasm, and cytoplasm. Maturation of the ribosomal small subunit is completed in the cytoplasm by incorporation of a particular class of ribosomal proteins and final cleavage of 18S-E pre-rRNA (18S-E). Here, we show that poly(A)-specific ribonuclease (PARN) participates in steps leading to 18S-E maturation in human cells. We found P...

Eukaryote ribosomal RNAs (rRNAs) have expanded in the course of phylogeny by addition of nucleotides in specific insertion areas, the expansion segments. These number about 40 in the larger (25-28S) rRNA (up to 2,400 nucleotides), and about 12 in the smaller (18S) rRNA (<700 nucleotides). Expansion of the larger rRNA shows a clear phylogenetic increase, with a dramatic rise in mammals and espec...

The participation of 18S, 5.8S and 28S ribosomal RNA in subunit association was investigated by chemical modification and primer extension. Derived 40S and 60S ribosomal subunits isolated from mouse Ehrlich ascites cells were reassociated into 80S particles. These ribosomes were treated with dimethyl sulphate and 1-cyclohexyl-3-(morpholinoethyl) carbodiimide metho-p-toluene sulfonate to allow s...

Ribosomal (r)RNAs are extensively modified during ribosome synthesis and their modification is required for the fidelity and efficiency of translation. Besides numerous small nucleolar RNA-guided 2'-O methylations and pseudouridinylations, a number of individual RNA methyltransferases are involved in rRNA modification. WBSCR22/Merm1, which is affected in Williams-Beuren syndrome and has been im...

One of the few rRNA modifications conserved between bacteria and eukaryotes is the base dimethylation present at the 3' end of the small subunit rRNA. In the yeast Saccharomyces cerevisiae, this modification is carried out by Dim1p. We previously reported that genetic depletion of Dim1p not only blocked this modification but also strongly inhibited the pre-rRNA processing steps that lead to the...

In physiologically nongrowing lymphocytes, the rate of entry of new ribosomal RNA (rRNA) molecules to the cytoplasm is only half the rate at which rRNA is synthesized in the nucleus, although there is no net nuclear accumulation of rRNA (6) . When total cell RNA is extracted from intact lymphocytes after moderately short labeling periods, the amount of radioactivity appearing in 18S rRNA is onl...

A new species, Robertgurneya jejuensis sp. nov., was described from sandy sediment samples collected at a depth of 25 m on Mun Island, Jeju, in June 2018. The species is morphologically similar to similis (Scott A., 1896) and donghaensis Bang, 2021; this the second record genus South Korea. morphological characteristics group within Robertgurneya, which ascribed, are summarized here. Furthermor...

The translational capacity of a rabbit reticulocyte lysate is rapidly abolished on treatment with angiogenin, an effect that is due to cleavage of rRNA [St. Clair, D. K., Rybak, S. M., Riordan, J. F., & Vallee, B. L. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 8330-8334]. The same time course of inhibition is seen when isolated ribosomes are treated with angiogenin prior to being added to a riboso...

BACKGROUND NIR was identified as an inhibitor of histone acetyltransferase and it represses transcriptional activation of p53. NIR is predominantly localized in the nucleolus and known as Noc2p, which is involved in the maturation of the 60S ribosomal subunit. However, how NIR functions in the nucleolus remains undetermined. In the nucleolus, a 47S ribosomal RNA precursor (pre-rRNA) is transcri...