Analysis of inter-species cross-contamination in 160 non-human cell lines / 基础医学与临床

Objective To analyze interspecies cross-contamination of 160 non-human cell lines.Methods One hundred and sixty common non-human cell lines were collected and their species were identified by PCR.For the suspicious cells,chromosome analysis was further used to confirm their species.Results Six in 160 non-human cell lines were cross-contaminated.A rat cell line was mixed by a human cell line,and 5 were totally cross-con-taminated,and were indentified as wrong species.Conclusions Species identification is an indispensable part of cell quality control.Each cell line should undergo a full QA(Quality Assurance)assessment before it is used for research.

Mycoplasma contamination decreases 28S and 18S RNC-rRNA via p38 MAPK pathways in human cell lines / 中国病理生理杂志

AIM:To evaluate the effect of mycoplasma on the rRNA composition of mature ribosomes in human cell lines.METHODS:We isolated ribosome nascent-chain complex ( RNC) from multiple mycoplasma-positive-negative human cell lines.RNC-RNA was acquired from each cell line through RNA extraction, followed by agarose gel separation, fluorescent visualization and gray-scale value measurements on the rRNA bands.Western blot analysis was performed to in-vestigate the MAPK pathway alterations.RESULTS:In various human cell lines derived from different tissues, we found that as compared with mycoplasma-negative cells, mycoplasma-positive cells showed aberrant RNC-rRNA band patterns, featured by the decreases in 28S and 18S eukaryotic rRNAs and the increases in 16S and other unknown prokaryotic rRNAs.When cultured without ciprofloxacin, mycoplasma-negative HBE cells acquired mycoplasma contamination as ob-served with such characteristic abnormal rRNA bands.The ciprofloxacin treatment was able to recover the RNC-rRNA bands of the mycoplasma-contaminated cells to the normal pattern.The results of Western blot analysis on total and phos-phorylated proteins indicated that p38 pathway was significantly deactivated in mycoplasma-infected A549 cells, while ERK1/2 pathway was not significantly altered.CONCLUSION:Mycoplasma contamination severely alters the RNC-rRNA composition via p38 MAPK pathway, thus seriously impacting on the host cell translational behaviors.

Antiproliferative activity of methanol extracts of four species of Croton on different human cell lines

Several species of Croton have been described with biological activities, mainly due to diterpenes, alkaloids and/or other secondary metabolites. These activities account for the traditional use of Croton species to treat certain diseases in South America, Asia and Western Africa. The crude methanol extracts obtained from leaves and steam bark of Croton dichrous Müll. Arg., C. erythroxyloides Baill., C. myrianthus Müll. Arg. and C. splendidus Mart. ex Colla were tested for antiproliferative activity against ten human cancer cell lines. Chemical analyses of all extracts were carried out by GC/MS and HPLC/MS/MS. The leaf extract obtained from C. erythroxyloides showed potent activity against PC-3 (prostate) and OVCAR-3 (ovary) cell lines. Lupeol is suggested to be involved in such activity. Tiliroside, an acyl-glycosilated flavonoid ubiquitous in all tested extracts, seems to play an important role in the observed moderate activity of most extracts against the leukemia K562 cell lineage.

Diversity of marine gliding bacteria in Thailand and their cytotoxicity

Eighty-four marine gliding bacteria were isolated from specimens collected in the Gulf of Thailand and the Andaman Sea. All exhibited gliding motility and swarm colonies on cultivation plates and they were purified by subculturing and micromanipulator techniques. Their 16S rRNA genes were amplified by the polymerase chain reaction (PCR) technique. The phylogenetic analysis indicated that the represented isolates can be separated into six different clads (gr 1 - gr 6) within the Cytophaga-Flavobacterium-Bacteriodes (CFB) group. Group 1 formed a remote linear, with only 90 percent sequence similarity, from Flavobacteriaceae bacterium which indicated a potentially novel taxonomic group. Groups 2 and 3 were identified as the recently proposed Tenacibaculum mesophilum and Fulvivirga kasyanovii respectively. Groups 4, 5 and 6, consisting of the largest number of the members, were identified as Rapidithrix thailandica, Aureispira marina and Aureispira maritima respectively. The isolates were cultivated in four different cultivation media (Vy/2, RL 1, CY and SK) and the crude extracts were submitted to screen cytotoxicity using a sulphorodamine B (SRB) assay. The results from cytotoxic screening showed that groups 2, 4 and 6 were capable of producing the cytotoxic metabolites against selected human cell lines (breast adenocarcinoma (MCF-7), colon cancer (HT-29), cervical cancer (HeLa) and oral cancer (KB)). However, groups 1, 3 and 5 did not produce metabolites with cytotoxicity when cultivated in the same cultivation media as the previous groups. CY medium was the only cultivation medium which could yield the cytotoxic metabolites against MCF-7.