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821.
822.
Dimitri Viza 《Biotherapy》1996,9(1-3):17-26
At the end of the 20th century, the triumph of biology is as indisputable as that of physics was at the end of the 19th century,
and so is the might of the inductive thought. Virtually all diseases have been seemingly conquered and HIV, the cause of AIDS,
has been fully described ten years after the onset of the epidemic. However, the triumph of biological science is far from
being complete. The toll of several diseases, such as cancer, continues to rise and the pathogenesis of AIDS remains elusive.
In the realm of inductive science, the dominant paradigm can seldom be challenged in a frontal attack, especially when it
is apparently successful, and only what Kuhn calls “scientific revolutions” can overthrow it. Thus, it is hardly surprising
that the concept of transfer factor is considered with contempt, and the existence of the moiety improbable: over forty years
after the introduction of the concept, not only its molecular structure remains unknown, but also its putative mode of action
contravenes dogmas of both immunology and molecular biology. And when facts challenge established dogmas, be in religion,
philosophy or science, they must be suppressed. Thus, results of heterodox research become henceforth nisi — i.e., valid unless
cause is shown for rescinding them, because they challenge the prevalent paradigm. However, when observations pertain to lethal
disorders, their suppression in the name of dogmas may become criminal. Because of the failure of medical science to manage
the AIDS pandemic, transfer factor, which has been successfully used for treating or preventing viral infections, may today
overcome a priori prejudice and rejection more swiftly. In science, as in life, certainties always end up by dying, and Copernicus’
vision by replacing that of Ptolemy. 相似文献
823.
824.
Daniel G. J. Smethurst Nikolay Kovalev Erica R. McKenzie Dimitri G. Pestov Natalia Shcherbik 《The Journal of biological chemistry》2020,295(50):17200
Protein biosynthesis is fundamental to cellular life and requires the efficient functioning of the translational machinery. At the center of this machinery is the ribosome, a ribonucleoprotein complex that depends heavily on Mg2+ for structure. Recent work has indicated that other metal cations can substitute for Mg2+, raising questions about the role different metals may play in the maintenance of the ribosome under oxidative stress conditions. Here, we assess ribosomal integrity following oxidative stress both in vitro and in cells to elucidate details of the interactions between Fe2+ and the ribosome and identify Mn2+ as a factor capable of attenuating oxidant-induced Fe2+-mediated degradation of rRNA. We report that Fe2+ promotes degradation of all rRNA species of the yeast ribosome and that it is bound directly to RNA molecules. Furthermore, we demonstrate that Mn2+ competes with Fe2+ for rRNA-binding sites and that protection of ribosomes from Fe2+-mediated rRNA hydrolysis correlates with the restoration of cell viability. Our data, therefore, suggest a relationship between these two transition metals in controlling ribosome stability under oxidative stress. 相似文献
825.
Dimitri Kalenitchenko Sonja K Fagervold Audrey M Pruski Gilles Vétion Mustafa Yücel Nadine Le Bris Pierre E Galand 《The ISME journal》2015,9(12):2657-2670
Wood falls on the ocean floor form chemosynthetic ecosystems that remain poorly studied compared with features such as hydrothermal vents or whale falls. In particular, the microbes forming the base of this unique ecosystem are not well characterized and the ecology of communities is not known. Here we use wood as a model to study microorganisms that establish and maintain a chemosynthetic ecosystem. We conducted both aquaria and in situ deep-sea experiments to test how different environmental constraints structure the assembly of bacterial, archaeal and fungal communities. We also measured changes in wood lipid concentrations and monitored sulfide production as a way to detect potential microbial activity. We show that wood falls are dynamic ecosystems with high spatial and temporal community turnover, and that the patterns of microbial colonization change depending on the scale of observation. The most illustrative example was the difference observed between pine and oak wood community dynamics. In pine, communities changed spatially, with strong differences in community composition between wood microhabitats, whereas in oak, communities changed more significantly with time of incubation. Changes in community assembly were reflected by changes in phylogenetic diversity that could be interpreted as shifts between assemblies ruled by species sorting to assemblies structured by competitive exclusion. These ecological interactions followed the dynamics of the potential microbial metabolisms accompanying wood degradation in the sea. Our work showed that wood is a good model for creating and manipulating chemosynthetic ecosystems in the laboratory, and attracting not only typical chemosynthetic microbes but also emblematic macrofaunal species. 相似文献
826.
827.
828.
Dr. Dharam V. Ablashi Paul H. Levine Caterina De Vinci James E. Whitman Jr. Giancarlo Pizza Dimitri Viza 《Biotherapy》1996,9(1-3):81-86
Specific Human Herpes virus-6 (HHV-6) transfer factor (TF) preparation, administered to two chronic fatigue syndrome patients,
inhibited the HHV-6 infection. Prior to treatment, both patients exhibited an activated HHV-6 infection. TF treatment significantly
improved the clinical manifestations of CFS in one patient who resumed normal duties within weeks, whereas no clinical improvement
was observed in the second patient. It is concluded that HHV-6 specific TF may be of significant value in controlling HHV-6
infection and related illnesses. 相似文献
829.
Kuang Yu Chen Dimitri A. Kyriakidis E.S. Canellakis 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,716(1):72-78
The addition of fresh serum-containing growth medium to L1210 mouse leukemic cells in culture resulted in a 5-fold increase in ornithine decarboxylase (l-ornithine carboxy-lyase, EC 4.1.1.17) activity. The presence of microtubule disrupting agents (colchine, vinblastine) or cations (5–10 mM K+, Na+ or Mg2+) abolishes this increase of ornithine decarboxylase activity (Chen, K.Y., Heller, J.S. and Canellakis, E.S. (1976) Biochem. Biophys. Res. Commun. 70, 212–219). Based on these observations we proposed that fluctuation in cellular cation concentrations may act as a link between the membrane structure and ornithine decarboxylase. To test this proposal, we studied the effects of selective membrane perturbing agents such as ionophores and local anesthetics, on the serum-stimulated increase of ornithine decarboxylase activity in L1210 cells. Among the six inonophores tested, valinomycin was the most potent one, with I50 value (concentration that gives 50% inhibition of orthinine decarbocylase activity) of 6·10?9 M. Dibucaine and tetracaine were also effective inhibitors at 10?4?10?5 M. The I50 values of valinomycin on the protein synthesis and RNA synthesis, however, were greater than 1·10?6 M. These results substantiate the notion that ornithine decarboxylase activity can be regulated at plasma membrane level and such regulation is related to the perturbation of cellular cation pools. 相似文献
830.