Search results for "iOS"

Serratia symbiotica from the aphid Cinara cedri: a missing link from facultative to obligate insect endosymbiont.

2011

The genome sequencing of Buchnera aphidicola BCc from the aphid Cinara cedri, which is the smallest known Buchnera genome, revealed that this bacterium had lost its symbiotic role, as it was not able to synthesize tryptophan and riboflavin. Moreover, the biosynthesis of tryptophan is shared with the endosymbiont Serratia symbiotica SCc, which coexists with B. aphidicola in this aphid. The whole-genome sequencing of S. symbiotica SCc reveals an endosymbiont in a stage of genome reduction that is closer to an obligate endosymbiont, such as B. aphidicola from Acyrthosiphon pisum, than to another S. symbiotica, which is a facultative endosymbiont in this aphid, and presents much less gene decay…

Cell volume homeostatically controls the rDNA repeat copy number and rRNA synthesis rate in yeast

2021

[Abstract] The adjustment of transcription and translation rates to the changing needs of cells is of utmost importance for their fitness and survival. We have previously shown that the global transcription rate for RNA polymerase II in budding yeast Saccharomyces cerevisiae is regulated in relation to cell volume. Total mRNA concentration is constant with cell volume since global RNApol II-dependent nascent transcription rate (nTR) also keeps constant but mRNA stability increases with cell size. In this paper, we focus on the case of rRNA and RNA polymerase I. Contrarily to that found for RNA pol II, we detected that RNA polymerase I nTR increases proportionally to genome copies and cell s…

Heat-Shock Proteins in Sea Urchin Embryos

1982

The production of heat-shock proteins in sea urchin embryos is accompanied by the appearance at the polysomal level of their relative mRNAs, as shown by their translation in a cell-free system; thus suggesting that the regulation of their production occurs at a transcriptional level. The mechanism for the inhibition of the bulk protein synthesis and for its reversal on the other hand should be looked for at a posttranscriptional level, since both these phenomena occur also in the presence of actinomycin D. The heat-shock proteins produced as early as at the mesenchyme blastula stage persist within the embryo at least till the pluteus stage.

Evolutionary convergence and nitrogen metabolism in Blattabacterium strain Bge, primary endosymbiont of the cockroach Blattella germanica.

2009

Bacterial endosymbionts of insects play a central role in upgrading the diet of their hosts. In certain cases, such as aphids and tsetse flies, endosymbionts complement the metabolic capacity of hosts living on nutrient-deficient diets, while the bacteria harbored by omnivorous carpenter ants are involved in nitrogen recycling. In this study, we describe the genome sequence and inferred metabolism of Blattabacterium strain Bge, the primary Flavobacteria endosymbiont of the omnivorous German cockroach Blattella germanica. Through comparative genomics with other insect endosymbionts and free-living Flavobacteria we reveal that Blattabacterium strain Bge shares the same distribution of functio…

GD3 ganglioside: A marker for the diagnosis and treatment of neuroectodermal tumors?

1986

Growth rates or radiobiological hypoxia are not correlated with local metabolite content in human melanoma xenografts with similar vascular network.

1995

Investigations were carried out on two lines of human melanomas (MF; n = 12 and EE; n = 13) xenografted in nude mice. The tumours were characterised by a similar vascular supply but showed a pronounced difference in the rate of volume growth and in the radiobiologically hypoxic fraction. The distribution of ATP, glucose and lactate in the tumours was investigated using quantitative bioluminescence and single photon imaging. Concentrations of the metabolites were obtained as global values for the entire tumour mass, in regions with densely packed, structurally intact tumour cells ('viable zones'), in areas with necrosis, stromal cells and fibrous material ('necrotic zones') and in adjacent n…

Health status of young children with cancer following discontinuation of therapy.

1987

This paper reports late effects and health status of 198 children who had cancer or leukemia diagnosed under 2 years of age and their therapies electively withdrawn. This series (92 neuroblastoma (NBL), 57 Wilms' tumor (WT), 46 acute lymphoblastic leukemia (ALL), and 3 non-Hodgkin's lymphoma) was followed for 1-12 years after discontinuation of therapy. Thirty-three children were diagnosed before 1973, 92 between 1973 and 1977, and 73 after 1977 in 16 Italian Pediatric Oncology Centers. As of December 1983, 176 children were reported to be alive and without evidence of primary cancer by physicians responsible for their care. One child died from a second primary tumor, two from late recurren…

Physical inactivity and low fitness deserve more attention to alter cancer risk and prognosis.

2015

Abstract Sedentary lifestyle is associated with elevated cancer risk whereas regular physical activity (PA) and high cardiorespiratory fitness (CRF) have the opposite effect, with several biologic mechanisms mediating such associations. There is a need for lifestyle interventions aimed at increasing the PA levels and CRF of the general population and particularly cancer survivors. Furthermore, provocative data suggest a dose-dependent benefit of increasing levels of PA and/or CRF against cancer risk or mortality. Thus, current PA guidelines (≥150 min/wk of moderate-to-vigorous PA) may not be sufficiently rigorous for preventing cancer nor for extending cancer survivorship. Research targetin…

Pharmacogenomics of Cameroonian traditional herbal medicine for cancer therapy

2011

Abstract Ethnopharmacological relevance A socio-economic burden associated with cancers is reported in Africa. Ethnopharmacological usages such as immune and skin disorders, inflammatory, and others chould be considered when selecting plants used to treat cancer, since these reflect disease states bearing relevance to cancer or a cancer symptoms. Materials and methods Documented compounds of Cameroonian medicinal plants were used as keywords in the National Cancer Institute (NCI) database to establish a library of cytotoxic compounds. Cellular and pharmacogenomic profiling was then performed for the 10 most cytotoxic natural products. By COMPARE and hierarchical cluster analyses, candidate …

MYC dosage compensation is mediated by miRNA-transcription factor interactions in aneuploid cancer

2021

Summary We hypothesize that dosage compensation of critical genes arises from systems-level properties for cancer cells to withstand the negative effects of aneuploidy. We identified several candidate genes in cancer multiomics data and developed a biocomputational platform to construct a mathematical model of their interaction network with micro-RNAs and transcription factors, where the property of dosage compensation emerged for MYC and was dependent on the kinetic parameters of its feedback interactions with three micro-RNAs. These circuits were experimentally validated using a genetic tug-of-war technique to overexpress an exogenous MYC, leading to overexpression of the three microRNAs …