Competence for genetic transformation in Streptococcus pneumoniae has been known for three decades to arise in growing cultures at a critical cell density, in response to a secreted protease-sensitive signal. We show that strain CP1200 produces a 17-residue peptide that induces cells of the species to develop competence. The sequence of the peptide was found to be H-Glu-Met-Arg-Leu-Ser-Lys-Phe-Phe-Arg-Asp-Phe-Ile-Leu-Gln-Arg- Lys-Lys-OH. A synthetic peptide of the same sequence was shown to be biologically active in small quantities and to extend the range of conditions suitable for development of competence. Cognate codons in the pneumococcal chromosome indicate that the peptide is made ribosomally. As the gene encodes a prepeptide containing the Gly-Gly consensus processing site found in peptide bacteriocins, the peptide is likely to be exported by a specialized ATP-binding cassette transport protein as is characteristic of these bacteriocins. The hypothesis is presented that this transport protein is encoded by comA, previously shown to be required for elaboration of the pneumococcal competence activator.
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http://dx.doi.org/10.1073/pnas.92.24.11140 | DOI Listing |
BMC Res Notes
January 2025
Bioinformatics Center, North-Eastern Hill University, Shillong, 793022, India.
Objectives: Nepenthes, sometimes known as tropical pitcher plants or monkey cups, is a carnivorous plant genus that contains more than 160 species. Nepenthes khasiana, India's sole representative of the genus, is a rare and endangered dioecious plant endemic to North-east India. Despite the fact that it is a prominent insectivorous plant in the Nepenthaceae family, genomic resources for the species are limited, making genomic breeding and understanding the genetic basis of botanical carnivory difficult.
View Article and Find Full Text PDFExp Hematol Oncol
January 2025
Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Clonal hematopoiesis of indeterminate potential (CHIP) is a condition where blood or bone marrow cells carry mutations associated with hematological malignancies. Individuals with CHIP have an increased risk of developing hematological malignancies, atherosclerotic cardiovascular disease, and all-cause mortality. Bone marrow transplantation (BMT) of cells carrying CHIP mutations into irradiated mice are useful procedures to investigate the dynamics of clonal expansion and potential therapeutic strategies, but myeloablative conditioning can induce confounding effects.
View Article and Find Full Text PDFJ Ovarian Res
January 2025
Department of Medical Genetics, National Taiwan University Hospital, 19F, No. 8, Chung-Shan South Road, Taipei City, Taiwan.
Background: The homologous recombination deficiency (HRD) test is an important tool for identifying patients with epithelial ovarian cancer (EOC) benefit from the treatment with poly(adenosine diphosphate-ribose) polymerase inhibitor (PARPi). Using whole exome sequencing (WES)-based platform can provide information of gene mutations and HRD score; however, the clinical value of WES-based HRD test was less validated in EOC.
Methods: We enrolled 40 patients with EOC in the training cohort and 23 in the validation cohort.
J Nanobiotechnology
January 2025
Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Extracellular vesicles (EVs) are taken up by most cells, however specific or preferential cell targeting remains a hurdle. This study aims to develop an EV that targets cells involved in inflammation, specifically those expressing intercellular adhesion molecule-1 (ICAM-1). To target these cells, we overexpress the ICAM-1 binding receptor "lymphocyte function-associated antigen-1" (LFA-1) in HEK293F cells, by sequential transfection of plasmids of the two LFA-1 subunits, ITGAL and ITGB2 (CD11a and CD18).
View Article and Find Full Text PDFOrphanet J Rare Dis
January 2025
Institute of Human Genetics, Leipzig University Medical Center, Leipzig, Germany.
Background: Cardiac rhabdomyoma (RHM) is considered one of the most frequent benign heart tumors in children. However, encounters with cardiac RHM in clinical practice remain rare. Clinical information is primarily available in the form of single case reports or smaller studies with a shortage of large-scale reviews encompassing a substantial number of cases.
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