Only One 3′-Hydroxyl Group Of ppp 5′A 2′p 5′A 2′p 5′A(2–5A) is Required for Activation of the Mouse 2–5A-Dependent Endonuclease

Abstract

The 3′-hydroxyl groups of each of the adenosines of 2–5A triraer (ppp5′A2′p5′A2′p5′A) were sequentially replaced by hydrogen through a phosphotriester synthetic approach. Biochemical evaluation of these analogs led to the conclusion that only the 3′-hydroxy group of the second adenosine is required for activation of RNase L.     

2',5'-Phosphodiesterase activity depends upon the presence of a 3'-hydroxyl moiety in the penultimate position of the oligonucleotide substrate

3'-Deoxyadenosine (3'dA, cordycepin)-substituted analogs of 2-5A core 5'-monophosphate (p5'A2'p5'A2'p5'A) were examined for their sensitivity toward degradation by the 2'-phosphodiesterase activity in cytoplasmic extracts of mouse L cells. The analogs, p5'(3'dA)-2'p5'A2'p5'A, p5'(3'dA)2'p5'A2'p5'(3'dA) and p5'A2'p5'A2'p5'(3'dA) were degraded at a rate comparable to p5'A2'p5'A2'p5'A itself. On the other hand, under the assay conditions examined p5'A2'p5'(3'dA)2'p5'A, like p5'(3'dA)2'p5'(3'dA)2'p5'(3'dA), was completely resistant to degradation. The data imply that sensitivity to the 2',5'-phosphodiesterase activity of mouse L cells requires the presence of 3'-hydroxyl moiety in the penultimate nucleotide.     

Synthesis and Biological Activity of a Bis-Substituted 3′-Deoxyadenosine Analog of 2–5A

Abstract

The 5′-monophosphate, p5′(3′dA)2′p5′A2′5′(3′dA), was synthesized and found to bind to the 2–5A-dependent endonuclease of mouse L cells only two-three times less effectively than the parent p5′A2′p5′A2′p5′A. When evaluated for its ability to activate the 2–5A-dependent endonuclease, ppp5′(3′dA)2′p5′A2′p5′(3′dA) was found to be fifty times more effective than ppp5′A2′p5′(3′dA)2′p5′A and ten times less effective than 2–5A as an endonuclease activator     

Effect of quinones on formation and properties of bacteriochlorophyll c aggregates

Chlorosomes of green photosynthetic bacterium Chlorobium tepidum contain aggregates of bacteriochlorophyll c (BChl c) with carotenoids and isoprenoid quinones. BChl aggregates with very similar optical properties can be prepared also in vitro either in non-polar solvents or in aqueous buffers with addition of lipids and/or carotenoids. In this work, we show that the aggregation of BChl c in aqueous buffer can be induced also by quinones (vitamin K₁ and K₂), provided they are non-polar due to a hydrophobic side-chain. Polar vitamin K_3, which possess the same functional group as K₁ and K₂, does not induce the aggregation. The results confirm a principal role of the hydrophobic interactions as a driving force for the aggregation of chlorosomal BChls. The chlorosomal quinones play an important role in a redox-dependent excitation quenching, which may protect the cells against damage under oxygenic conditions. We found that aggregates of BChl c with vitamin K₁ and K₂ exhibit an excitation quenching as well. The amplitude of the quenching depends on quinone concentration, as determined from fluorescence measurements. No lipid is necessary to induce the quenching, which therefore originates mainly from interactions of BChl c with quinones incorporated in the aggregate structure. In contrast, only a weak quenching was observed for dimers of BChl c in buffer (either with or without vitamin K₃) and also for BChl c aggregates prepared with a lipid (lecithin). Thus, the weak quenching seems to be a property of BChl c itself.     

Quantitation of oncogene products by computer-assisted image analysis and flow cytometry

The use of antibodies permits the study of oncogene product expression in cells and tissues. However, quantitation of the levels of expression in immunohistochemical preparations is beset by difficulties, and the available scoring system provide semiquantitative data at best. Here we describe the use of computer-assisted image analysis for determination of oncoprotein levels in a model system and compare the results with those generated by flow cytometric analysis. The oncogene products measured are located in the nucleus (c-myc p62 and c-fos p55), the inner surface of the membrane (c-ras p21), and both sides of the membrane (c-erbB-2 p185). In each instance, both analytic modalities yielded concordant results. Our data indicate that computer-assisted image analysis is a useful tool for quantitating cell components in immunohistochemical preparations.     

Side effects and complications of variable-pulsed erbium:yttrium-aluminum-garnet laser skin resurfacing: extended experience with 50 patients

Recent advances in technology have provided laser surgeons with new options for cutaneous laser resurfacing. Despite its popularity, there is limited information on the short-term and long-term side effects and complications of variable-pulsed erbium:yttrium-aluminum-garnet (erbium:YAG) laser skin resurfacing. The purpose of this study was to prospectively evaluate postoperative wound healing, side effects, and complications of multiple-pass, variable-pulsed erbium:YAG laser skin resurfacing for facial photodamage, rhytides, and atrophic scarring. Fifty consecutive patients with facial photodamage, rhytides, or atrophic scarring were treated with a variable-pulsed erbium:YAG laser. Side effects and complications relating to postoperative healing, erythema, and pigmentary changes were tabulated. Patients were evaluated at postoperative days 3 through 7 and at 1, 3, 6, and 12 months after laser skin resurfacing. The average time for reepithelialization was 5.1 days. Prolonged erythema (>1 month) was observed in three patients (6 percent). Transient hyperpigmentation occurred in 20 patients (40 percent), with an average duration of 10.4 weeks. No cases of hypopigmentation or scarring were seen. In summary, a variable-pulsed erbium:YAG laser can safely be used for the treatment of facial photodamage, rhytides, and atrophic scarring. Although more postoperative erythema is seen after variable-pulsed erbium:YAG laser treatment than is usually produced with a short-pulsed erbium:YAG system, the side-effect profile and recovery period after variable-pulsed erbium:YAG laser skin resurfacing still are more favorable than after multiple-pass carbon dioxide laser skin resurfacing.     

Increased level of cholecystokinin in cerebrospinal fluid is associated with chronic pain-like behavior in spinally injured rats.

Cholecystokinin (CCK) is a physiological antagonist of opioid-mediated antinociception and may be involved in some chronic pain states where opioids have reduced effect. We have previously shown in a rat model of central neuropathic pain after spinal cord injury that blockade of CCK-B receptors lead to marked pain relief. In the present study, we showed that spinally injured rats exhibiting chronic pain-like behaviors (aversive reaction to innocuous mechanical and cold stimulation) had significantly elevated level of CCK-like immunoreactivity in cerebrospinal fluid compared to normal rats or spinally injured rats which did not exhibit pain-like behaviors. The increased level of circulating CCK in the cerebrospinal fluid may thus contribute to the maintenance of chronic pain in these rats by reducing the endogenous inhibitory tone provided by opioid peptides and may be involved in the phenomenon of opioid insensitivity.     

Human-derived and new synthetic injectable materials for soft-tissue augmentation: current status and role in cosmetic surgery

The recent development of human-derived and new synthetic filling agents heralds a new era in soft-tissue augmentation. Many of the disadvantages of xenogenic and prior exogenous materials have been overcome with the advent of these autologous, allogeneic, and inert synthetic alternatives. Early reports using human-derived and inert exogenous filling agents have demonstrated good results and prolonged correction. It is too early, however, to assess the long-term efficacy of these agents. Future investigations should include histologic examination after facial implantation to document long-term safety and efficacy.     

Stable patterns in size structure of a phytoplankton species of Lake Kinneret

The aim of the study was a search for typical structure patterns of phytoplankton assemblages, based on the long-term dynamics analysis. As a test case we used the interannual phytoplankton variability of Lake Kinneret (Israel). The dominant phytoplankton species (Peridinium gatunense) structure was presented as the frequency-weighted taxonomic size spectrum (TSS) which describes the size distribution of the operational taxonomic unit (OTUj) occurrence frequencies. Using 24 years monitoring data, the TSS annual patterns of P. gatunense were compared. Typical persistent TSS patterns were evident even during years of pronounced deviations from the typical patterns of phytoplankton biomass dynamics and species composition. By correlation analysis, hierarchical cluster analysis and ANOVA the TSS variability was quantified and compared. While the TSS general shape was almost constant, its amplitude variations allowed us to distinguish between three levels of annual bloom intensity. Electronic Supplementary Material Supplementary material is available for this article at and accessible for authorised users