Genomic organization, sequence and polymorphism of the human chromosome 4-specific a-satellite DNA

Two -satellite fragments specific for human chromosome 4 have been cloned and characterized. Under stringent annealing conditions, they hybridized in situ only to the pericentromeric region of chromosome 4, but under nonstringent conditions they hybridized to all chromosomes containing the sequences of -satellite suprachromosomal family 2 (viz., chromosomes 2, 4, 8, 9, 13, 14, 15, 18, 20, 21 and 22). Southern blot analysis reveals the 3.2-kb higher-order repeated unit which exists in two forms: as a single MspI fragment or a combination of the 2.6-kb and 0.6-kb MspI fragments. The two chromosome-4-specific cloned sequences appear to be different parts of this repeated unit. Taken together they constitute about 60% of its length. The primary structure of the higher-order repeated unit is characterized by a dimeric periodicity of the D1-D2 type which is usual to suprachromosomal family 2. At least in one site this regularity is disrupted by monomer deletion leading to the D2-D2 monomeric order. The most likely mechanism of this monomer excision is homologous unequal crossing-over. These sequences may serve as both cytogenetic and restriction-fragment length polymorphism (RFLP) markers for the pericentromeric region of chromosome 4.     

Production of urinary tumour necrosis factors and soluble tumour necrosis factor receptors in bladder cancer patients afterbacillus Calmette-Guerin immunotherapy

Intravesical immunotherapy for bladder cancer is the most effective form of tumour immunotherapy. Following repeated instillations of bacillus Calmette-Guérin (BCG) organisms into the bladder large 0quantities of several cytokines are detected in the urine. These cytokines include interleukins IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor α (TNFα), interferon γ (IFNγ) and also soluble intercellular adhesion molecule ICAM-1. In the work reported here we simultaneously quantified urinary levels of TNFα, TNFβ, TNF receptor I and TNF receptor II by enzyme-linked immunosorbent assay (ELISA) techniques and compared this with bioactive levels of TNF. This was undertaken with a limited number of patients throughout a course of six instillations of immuno therapy. Sequential instillations of BCG induced secretion of TNFα and TNFβ into urine. These cytokines were not always secreted simultaneously, perhaps suggesting differential regulation of their synthesis. Maximal concentrations of TNFα were 675 pg/ml and TNFβ 47 pg/ml. High levels of both species of soluble TNF receptor were readily identified in urine. Maximal levels of sTNF-RI were 6200 pg/ml (range from 0) and for sTNF-RII 7800 pg/ml (range from 0). Contrasting with earlier published observations concerning cytokine levels, the concentration of soluble receptor did not increase with repeated instillation. In apparent contrast with the ELISA data, very low levels of bioactive TNF were identified by the L929 bioassay (maximum concentration 1 U/ml) despite the elevated concen t ration of immunoreactive TNF. The large concentrations of soluble TNF receptor in patients’ urine samples could account for the apparently low bioactivity as determined by the L929 cytotoxicity assay. The precise nature of the role of TNF in BCG immunotherapy remains undetermined; however, it is thought that proinflammatory cytokines are in part responsible for the clinical efficacy of this therapeutic approach. Whether other cytokines are antogonised by soluble binding proteins remains to be determined. Furthermore, whether TNF is bioactive in the bladder wall and only neutralised in the urine also requires investigation. Received: 24 August 1994 / Accepted: 17 October 1994     

Regions of homology in small colicinogenic plasmids

Restriction maps have been constructed for the colicinogenic plasmids (ColA, ColD, and ColK. Their regions of homology with the ColE1 plasmid and its deletion derivative pAO3 carrying the region responsible for autonomous replication of ColE1 plasmid were determined by means of blotting hybridization and heteroduplex analysis. The plasmids ColA, ColD, and ColK were shown to contain DNA fragments homologous to the region of ColE1 involved in the regulation of replication.     

Incidence of Q fever in two inadequately investigated occupational groups.

In 1973 the authors investigated the incidence of Q fever serologically by means of the reaction of complement fixation (RCF) and the method of immunofluorescent titration (MIFT) in two inadequately investigated occupational groups--communal workers from the town of Russe and medical workers in obstetric departments of several towns in North Bulgaria. In addition, they carried out comparative studies in order to characterize the incidence and the degree of affection from the same disease in other persons exposed and not exposed at work in the same area--transport workers and blood donors. Out of 198 communal workers, 91 (45.95 +/- 3.54%) had positive titres for Q fever (1:8--1:512). A high incidence of Q fever was established in dustmen (61.40%), sweepers (46.55%) and drivers of dust cars (38.00%), i.e. persons collecting and rendering harmless the garbage of big town. Out of 174 medical workers in obstetric departments 65 (37.36% +/- 3.78%) were positive in titres 1:8--1:512. A high incidence of Q fever was established in obstetricians (57.14%), midwives (38.11%) and hospital attendants (34.38%), i.e. persons providing medical care for pregnant women or women in childbirth. In both groups the occupational hazard increases with the length of service. Out of 244 transport workers 82 (33.60% +/- 3.02%) were positive for Q fever, and out of 237 blood donors 19 (8.01 +/- 2.54%) were serologically positive for Q fever. The authors suggest continued investigation of these two occupational groups.     

Chromosome-specific alpha satellites: two distinct families on human chromosome 18.

Two types of human chromosome 18-specific alpha satellite fragments have been cloned and sequenced. They represent closely related but distinct alphoid families formed by two different types of the higher-order repeated units (1360-bp EcoRI and 1700-bp HindIII fragments) that do not alternate in the genome. The individual repeats within each family are 99% identical and interfamily homology is about 78%. Sequence analysis shows that both repeats belong to alphoid suprachromosomal family 2, but their homology is not higher than that of family members located on different chromosomes. Therefore, the two repeats shared a common origin in the recent past, although they are not the direct offspring of one ancestral sequence. Our data indicate that these two 18-specific domains have appeared as a result of two separate amplification events. Despite the high degree of homology, they are not undergoing intrachromosomal homogenization, although some variation of this process might take place within each domain.     

Comparison of the metabolism of benzo[alpha]pyrene and binding to DNA caused by rat liver nuclei and microsomes.

Administration of 3-methylcholanthrene (3MC) to rats greatly enhanced the aryl hydrocarbon hydroxylase (AHH) activity of liver nuclei. However, the binding in vitro [3H]benzo[alpha]pyrene (BP) to DNA within the nuclei which occurred at the same time as hydroxylation of BP was much less enhanced. Thin layer chromatography of the metabolites of BP produced by these nuclei revealed the same metabolites in similar relative amounts as were produced by rat liver microsomes prepared from rats which had received 3MC. The binding to DNA was further analysed by hydrolysis of the DNA and fractionation on a Sephadex column. This analysis revealed that the binding to DAN in nuclei was very similar in nature to that which occurred when calf-thymus DNA was added to microsomes metabolising BP.     

DESI-MSI and METASPACE indicates lipid abnormalities and altered mitochondrial membrane components in diabetic renal proximal tubules

Metabolomics - Food and dietary ingredients have significant effects on metabolism and health. To evaluate whether and how different diets affected the serum lipidomic profile of dogs. Sixteen...     

Could yeast prion domains originate from polyQ/N tracts?

A significant body of evidence shows that polyglutamine (polyQ) tracts are important for various biological functions. The characteristic polymorphism of polyQ length is thought to play an important role in the adaptation of organisms to their environment. However, proteins with expanded polyQ are prone to form amyloids, which cause diseases in humans and animals and toxicity in yeast. Saccharomyces cerevisiae contain at least 8 proteins which can form heritable amyloids, called prions, and most of them are proteins with glutamine- and asparagine-enriched domains. Yeast prion amyloids are susceptible to fragmentation by the protein disaggregase Hsp104, which allows them to propagate and be transmitted to daughter cells during cell divisions. We have previously shown that interspersion of polyQ domains with some non-glutamine residues stimulates fragmentation of polyQ amyloids in yeast and that yeast prion domains are often enriched in one of these residues. These findings indicate that yeast prion domains may have derived from polyQ tracts via accumulation and amplification of mutations. The same hypothesis may be applied to polyasparagine (polyN) tracts, since they display similar properties to polyQ, such as length polymorphism, amyloid formation and toxicity. We propose that mutations in polyQ/N may be favored by natural selection thus making prion domains likely by-products of the evolution of polyQ/N.     

Tranexamic acid suppresses the release of mitochondrial DNA,protects the endothelial monolayer and enhances oxidative phosphorylation

Damage-associated molecular patterns, including mitochondrial DNA (mtDNA) are released during hemorrhage resulting in the development of endotheliopathy. Tranexamic acid (TXA), an antifibrinolytic drug used in hemorrhaging patients, enhances their survival despite the lack of a comprehensive understanding of its cellular mechanisms of action. The present study is aimed to elucidate these mechanisms, with a focus on mitochondria. We found that TXA inhibits the release of endogenous mtDNA from granulocytes and endothelial cells. Furthermore, TXA attenuates the loss of the endothelial monolayer integrity induced by exogenous mtDNA. Using the Seahorse XF technology, it was demonstrated that TXA strongly stimulates mitochondrial respiration. Studies using Mitotracker dye, cells derived from mito-QC mice, and the ActivSignal IPAD assay, indicate that TXA stimulates biogenesis of mitochondria and inhibits mitophagy. These findings open the potential for improvement of the strategies of TXA applications in trauma patients and the development of more efficient TXA derivatives.     

Characterizing Mutational Signatures in Human Cancer Cell Lines Reveals Episodic APOBEC Mutagenesis

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