Anti-inflammatory and cytotoxic activities of chichipegenin, peniocerol, and macdougallin isolated from Myrtillocactus geometrizans (Mart. ex Pfeiff.) Con

The oleanane-type triterpene chichipegenin and the sterols peniocerol and macdougallin, isolated from Myrtillocactus geometrizans, showed anti-inflammatory activities in both the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema model and the carrageenan-induced rat paw edema model. All tested compounds inhibited the TPA-induced edema in a dose-dependent manner, with ED50 values less than or equal to that shown by indomethacin. Among them, peniocerol was the most active compound. However, only peniocerol and macdougallin reduced carrageenan-induced rat paw edema. On the other hand, peniocerol and macdougallin showed cytotoxicity against several human cancer cell lines. These results indicate that compounds isolated from M. geometrizans possess antiinflammatory and cytotoxic properties, and the presence of chichipegenin in the aerial parts could justify the medicinal uses attributed to the plant.     

State of hepatitis B viral DNA in a human hepatoma cell line.

PLC/PRF/5, a tissue culture cell line isolated from a human hepatocellular carcinoma and producing hepatitis B surface antigen, was studied for the presence of hepatitis B virus (HBV)-specific DNA and RNA. PLC/PRF/5 cell DNA accelerated the rate of reassociation of HBV [32P]DNA, and quantitative experiments indicated that the cells contained approximately four copies of viral DNA per haploid, mammalian cell DNA equivalent. PLC/PRF/5 DNA accelerated the rate of reassociation of all individual restriction endonucleases HincII and HaeIII fragments of HBV [32P]DNA, indicating that DNA from all regions of the viral genome is present in the cells. This suggests that these cells contain at least most, and possibly all, of the viral genome. Digestion of PLC/PRF/5 cell DNA with restriction endonuclease HindIII (an enzyme found not to cleave the DNA of any HBV isolate so far examined) yielded only three fragments, all larger than virion DNA, which contained HBV DNA base sequences, suggesting that HBV DNA is integrated in high-molecular-weight DNA at three different sites in these cells and that there is no viral DNA in an episomal form. PLC/PRF/5 cell [32P]RNA was found to hybridize with all restriction fragments of HBV DNA adequately tested, indicating that at least most, and possibly all, of the viral DNA in these cells is transcribed.     

Expression of nonstructural rotavirus protein NSP4 mimics Ca2+ homeostasis changes induced by rotavirus infection in cultured cells

Rotavirus infection modifies Ca²⁺ homeostasis, provoking an increase in Ca²⁺ permeation, the cytoplasmic Ca²⁺ concentration ([Ca²⁺]_cyto), and total Ca²⁺ pools and a decrease in Ca²⁺ response to agonists. A glycosylated viral protein(s), NSP4 and/or VP7, may be responsible for these effects. HT29 or Cos-7 cells were infected by the SA11 clone 28 strain, in which VP7 is not glycosylated, or transiently transfected with plasmids coding for NSP4-enhanced green fluorescent protein (EGFP) or NSP4. The permeability of the plasma membrane to Ca²⁺ and the amount of Ca²⁺ sequestered in the endoplasmic reticulum released by carbachol or ATP were measured in fura-2-loaded cells at the single-cell level under a fluorescence microscope or in cell suspensions in a fluorimeter. Total cell Ca²⁺ pools were evaluated as ⁴⁵Ca²⁺ uptake. Infection with SA11 clone 28 induced an increase in Ca²⁺ permeability and ⁴⁵Ca²⁺ uptake similar to that found with the normally glycosylated SA11 strain. These effects were inhibited by tunicamycin, indicating that inhibition of glycosylation of a viral protein other than VP7 affects the changes of Ca²⁺ homeostasis induced by infection. Expression of NSP4-EGFP or NSP4 in transfected cells induced the same changes observed with rotavirus infection, whereas the expression of EGFP or EGFP-VP4 showed the behavior of uninfected and untransfected cells. Increased ⁴⁵Ca²⁺ uptake was also observed in cells expressing NSP4-EGFP or NSP4, as evidenced in rotavirus infection. These results indicate that glycosylated NSP4 is primarily responsible for altering the Ca²⁺ homeostasis of infected cells through an initial increase of cell membrane permeability to Ca²⁺.     

Anti-atherogenic and anti-angiogenic activities of polyphenols from propolis

Propolis is a polyphenol-rich resinous substance extensively used to improve health and prevent diseases. The effects of polyphenols from different sources of propolis on atherosclerotic lesions and inflammatory and angiogenic factors were investigated in LDL receptor gene (LDLr?/?) knockout mice. The animals received a cholesterol-enriched diet to induce the initial atherosclerotic lesions (IALs) or advanced atherosclerotic lesions (AALs). The IAL or AAL animals were divided into three groups, each receiving polyphenols from either the green, red or brown propolis (250 mg/kg per day) by gavage. After 4 weeks of polyphenol treatment, the animals were sacrificed and their blood was collected for lipid profile analysis. The atheromatous lesions at the aortic root were also analyzed for gene expression of inflammatory and angiogenic factors by quantitative real-time polymerase chain reaction and immunohistochemistry. All three polyphenol extracts improved the lipid profile and decreased the atherosclerotic lesion area in IAL animals. However, only polyphenols from the red propolis induced favorable changes in the lipid profiles and reduced the lesion areas in AAL mice. In IAL groups, VCAM, MCP-1, FGF, PDGF, VEGF, PECAM and MMP-9 gene expression was down-regulated, while the metalloproteinase inhibitor TIMP-1 gene was up-regulated by all polyphenol extracts. In contrast, for advanced lesions, only the polyphenols from red propolis induced the down-regulation of CD36 and the up-regulation of HO-1 and TIMP-1 when compared to polyphenols from the other two types of propolis. In conclusion, polyphenols from propolis, particularly red propolis, are able to reduce atherosclerotic lesions through mechanisms including the modulation of inflammatory and angiogenic factors.     

Existence of atrial natriuretic peptide in choroid, retina and ciliary body in rabbits]

The presence of atrial natriuretic factor (ANF) in choroid, retina and ciliary body of rabbit eyes has been studied. The peptide was extracted by reverse phase chromatography using Sep-Pak C18 cartridges. Immunoreactive ANF (Ir-ANF) was measured by a specific RIA. In the choroid, retina and ciliary body the ir-ANF concentrations were 444 +/- 94, 67 +/- 12 and 223 +/- 75 pg/g tissue weight (n = 16), respectively. The biological activity of the acid extract ANF was evaluated by a 125I-ANF binding assay to a retinal particulate preparation. Results demonstrate the existence of biological active ANF in choroid, retina and ciliary body of rabbit eyes. The presence of ANF and its specific receptors in the ocular tissues suggests that this hormone might play a physiological role in the intraocular fluid homeostasis.     

Dynamics of fine root carbon in Amazonian tropical ecosystems and the contribution of roots to soil respiration

Radiocarbon (¹⁴C) provides a measure of the mean age of carbon (C) in roots, or the time elapsed since the C making up root tissues was fixed from the atmosphere. Radiocarbon signatures of live and dead fine (<2 mm diameter) roots in two mature Amazon tropical forests are consistent with average ages of 4–11 years (ranging from <1 to >40 years). Measurements of ¹⁴C in the structural tissues of roots known to have grown during 2002 demonstrate that new roots are constructed from recent (<2‐year‐old) photosynthetic products. High Δ¹⁴C values in live roots most likely indicate the mean lifetime of the root rather than the isotopic signature of inherited C or C taken up from the soil. Estimates of the mean residence time of C in forest fine roots (inventory divided by loss rate) are substantially shorter (1–3 years) than the age of standing fine root C stocks obtained from radiocarbon (4–11 years). By assuming positively skewed distributions for root ages, we can effectively decouple the mean age of C in live fine roots (measured using ¹⁴C) from the rate of C flow through the live root pool, and resolve these apparently disparate estimates of root C dynamics. Explaining the ¹⁴C values in soil pore space CO₂, in addition, requires that a portion of the decomposing roots be cycled through soil organic matter pools with decadal turnover time.     

Expression of a Bacillus thuringiensisdelta-endotoxin cry1Ab gene in Bacillus subtilis and Bacillus licheniformis strains that naturally colonize the phylloplane of tomato plants (Lycopersicon esculentum,Mills)

AIMS: To introduce a cry gene into microorganisms that naturally colonize the phylloplane of tomato plants to improve the persistence of the Cry proteins for controlling a South American tomato moth (Tuta absoluta, Meyrick, 1917). METHODS AND RESULTS: A cry1Ab gene isolated from a native Bacillus thuringiensis strain (LM-466), showing a relevant activity against T. absoluta larvae, was cloned into the shuttle vector pHT315 (Arantes and Lereclus 1991). The construct was introduced by electroporation into native Bacillus subtilis and Bacillus licheniformis strains, both natural inhabitants of the tomato phylloplane. Western analysis and toxicity assays against the target larvae proved that the successful expression of the gene was accomplished in host bacteria. Recombinant toxin displayed a similar LC50 value in comparison to native donor strain LM-466. Both transformed Bacillus survived for at least 45 days on the tomato leaf surface. CONCLUSIONS: Plant-associated microorganisms that naturally colonize the phylloplane could be useful as recombinant microbial delivery systems of toxin genes of B. thuringiensis. SIGNIFICANCE AND IMPACT OF THE STUDY: Modified microorganisms capable of surviving on leaf surfaces for several weeks with insecticidal activity should allow for a reduction in pesticide application.