Characterization of Rubus fruticosus mitochondria and salicylic acid inhibition of reactive oxygen species generation at Complex III/Q cycle: potential implications for hypersensitive response in plants

In addition to adenosine triphosphate (ATP) production, mitochondria have been implicated in the regulation of several physiological responses in plants, such as programmed cell death (PCD) activation. Salicylic acid (SA) and reactive oxygen species (ROS) are essential signaling molecules involved in such physiological responses; however, the mechanisms by which they act remain unknown. In non-photosynthesizing tissues, mitochondria appear to serve as the main source of ROS generation. Evidence suggests that SA and ROS could regulate plant PCD through a synergistic mechanism that involves mitochondria. Herein, we isolate and characterize the mitochondria from non-photosynthesizing cell suspension cultures of Rubus fruticosus. Furthermore, we assess the primary site of ROS generation and the effects of SA on isolated organelles. Mitochondrial Complex III was found to be the major source of ROS generation in this model. In addition, we discovered that SA inhibits the electron transport chain by inactivating the semiquinone radical during the Q cycle. Computational analyses confirmed the experimental data, and a mechanism for this action is proposed.

Role of phospholipase C and protein kinase C in Aspergillus nidulans during growth on pectin or glucose: Effects on germination and duplication cycle

The effects of PLC and Pkc inhibitors on Aspergillus nidulans depend on the carbon source. PLC inhibitors Spm and C48/80 delayed the first nuclear division in cultures growing on glucose, but stimulated it in media supplemented with pectin. Less intense were these effects on the mutant transformed with PLC-A gene rupture (AP27). Neomycin also delayed the germination in cultures growing on glucose or pectin; however, on glucose, the nuclear division was inhibited whereas in pectin it was stimulated. These effects were minor in AP27. The effects of Ro-31-8425 and BIM (both Pkc inhibitors) were also opposite for cultures growing on glucose or pectin. On glucose cultures of both strains BIM delayed germination and the first nuclear division, whereas on pectin both parameters were stimulated. Opposite effects were also detected when the cultures were growing on glucose or pectin in the presence of Ro-31-8425.

Interference of dexamethasone in the pulmonary cycle of Strongyloides venezuelensis in rats

The aim of this study was to investigate the interference of a daily treatment of dexamethasone in the pulmonary cycle of Strongyloides venezuelensis infection in rats. Three principal effects were found: 1) increased alveolar hemorrhagic inflammation provoked by the passage of larvae into alveolar spaces; 2) significant decrease of eosinophil and mast cell migration to the axial septum of the lungs; and 3) impaired formation of the reticular fiber network, interfering with granuloma organization. This study showed that the use of drugs with immunomodulatory actions, such as dexamethasone, in addition to interfering with the morbidity from the pulmonary cycle of S. venezuelensis infection, may contribute to showing the mechanisms involved in its pathogenesis.

Cell cycle arrest evidence, parasiticidal and bactericidal properties induced by L-amino acid oxidase from Bothrops atrox snake venom

The present article describes an L-amino acid oxidase from Bothrops atrox snake venom as with antiprotozoal activities in Trypanosoma cruzi and in different species of Leishmania (Leishmania braziliensis, Leishmania donovani and Leishmania major). Leishmanicidal effects were inhibited by catalase, suggesting that they are mediated by H(2)O(2) production. Leishmania spp. cause a spectrum of diseases, ranging from self-healing ulcers to disseminated and often fatal infections, depending on the species involved and the host`s immune response. BatroxLAAO also displays bactericidal activity against both Gram-positive and Gram-negative bacteria. The apoptosis induced by BatroxLAAO on HL-60 cell lines and PBMC cells was determined by morphological cell evaluation using a mix of fluorescent dyes. As revealed by flow cytometry analysis, suppression of cell proliferation with BatroxLAAO was accompanied by the significant accumulation of cells in the G0/G1 phase boundary in HL-60 cells. BatroxLAAO at 25 mu g/mL and 50 mu g/mL blocked G0-G1 transition, resulting in G0/G1 phase cell cycle arrest, thereby delaying the progression of cells through S and G2/M phase in HL-60 cells. This was shown by an accentuated decrease in the proportion of cells in S phase, and the almost absence of G2/M phase cell population. BatroxLAAO is an interesting enzyme that provides a better understanding of the ophidian envenomation mechanism, and has biotechnological potential as a model for therapeutic agents. (C) 2011 Elsevier Masson SAS. All rights reserved.

3,5-cycle decompositions

For all odd integers n and all non-negative integers r and s satisfying 3r + 5s = n(n -1)/2 it is shown that the edge set of the complete graph on n vertices can be partitioned into r 3-cycles and s 5-cycles. For all even integers n and all non-negative integers r and s satisfying 3r + 5s = n(n-2)/2 it is shown that the edge set of the complete graph on n vertices with a 1-factor removed can be partitioned into r 3-cycles and s 5-cycles. (C) 1998 John Wiley & Sons, Inc.

A DNA-based demonstration of a three-host life-cycle for the Bivesiculidae (Platyhelminthes : Digenea)

Immature bivesiculid trematodes collected from the intestine of Thalassoma lunare (Labridae) are shown to be morphologically consistent with adults of Bivesicula claviformis from Epinephelus fasciatus (Serranidae). In addition, the immature bivesiculids have the same sequence for the second internal transcribed spacer of the ribosomal DNA. Comparison with three other species of Bivesiculidae showed differences of between 23% and 30%. These results show that bivesiculids may have three-host life-cycles in addition to the two-host life-cycles that have been demonstrated previously. The three-host life-cycle enables bivesiculids to infect large carnivorous fishes. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd. All rights reserved.

5-cycle systems of K-v-F with a hole

Recently the problem of the existence of a 5-cycle system of K-v with a hole of size u was completely solved. In this paper we prove necessary and sufficient conditions on v and u for the existence of a 5-cycle system of K-v - F, with a hole of size u.

(m,n)-cycle systems

We describe a method which, in certain circumstances, may be used to prove that the well-known necessary conditions for partitioning the edge set of the complete graph on an odd number of vertices (or the complete graph on an even number of vertices with a 1-factor removed) into cycles of lengths m(1),m(2),...,m(t) are sufficient in the case \{m(1), m(2), ..., m(t)}\=2. The method is used to settle the case where the cycle lengths are 4 and 5. (C) 1998 Elsevier Science B.V. All rights reserved.

V4 region of small subunit rDNA indicates polyphyly of the Fellodistomidae (Digenea) which is supported by morphology and life-cycle data

There is no morphological synapomorphy for the disparate digeneans, the Fellodistomidae Nicoll, 1909. Although all known life-cycles of the group include bivalves as first intermediate hosts, there is no convincing morphological synapomorphy that can be used to unite the group. Sequences from the V4 region of small subunit (18S) rRNA genes were used to infer phylogenetic relationships among 13 species of Fellodistomidae from four subfamilies and eight species from seven other digenean families: Bivesiculidae; Brachylaimidae; Bucephalidae; Gorgoderidae; Gymnophallidae; Opecoelidae; and Zoogonidae. Outgroup comparison was made initially with an aspidogastrean. Various species from the other digenean families were used as outgroups in subsequent analyses. Three methods of analysis indicated polyphyly of the Fellodistomidae and at least two independent radiations of the subfamilies, such that they were more closely associated with other digeneans than to each other. The Tandanicolinae was monophyletic (100% bootstrap support) and was weakly associated with the Gymnophallidae (< 50-55% bootstrap support). Monophyly of the Baccigerinae was supported with 78-87% bootstrap support, and monophyly of the Zoogonidae + Baccigerinae received 77-86% support. The remaining fellodistomid species, Fellodistomum fellis, F. agnotum and Coomera brayi (Fellodistominae) plus Proctoeces maculatus and Complexobursa sp. (Proctoecinae), formed a separate clade with 74-92% bootstrap support. On the basis of molecular, morphological and life-cycle evidence, the subfamilies Baccigerinae and Tandanicolinae are removed from the Fellodistomidae and promoted to familial status. The Baccigerinae is promoted under the senior synonym Faustulidae Poche, 1926, and the Echinobrevicecinae Dronen, Blend & McEachran, 1994 is synonymised with the Faustulidae. Consequently, species that were formerly in the Fellodistomidae are now distributed in three families: Fellodistomidae; Faustulidae (syn. Baccigerinae Yamaguti, 1954); and Tandanicolidae Johnston, 1927. We infer that the use of bivalves as intermediate hosts by this broad range of families indicates multiple host-switching events within the radiation of the Digenea.

Life-cycle preferences over consumption and health: when is cost-effectiveness analysis equivalent to cost-benefit analysis?

This paper studies life-cycle preferences over consumption and health status. We show that cost-effectiveness analysis is consistent with cost-benefit analysis if the Lifetime utility function is additive over time, multiplicative in the utility of consumption and the utility of health status, and if the utility of consumption is constant over time. We derive the conditions under which the lifetime utility function takes this form, both under expected utility theory and under rank-dependent utility theory, which is currently the most important nonexpected utility theory. If cost-effectiveness analysis is consistent with cost-benefit analysis, it is possible to derive tractable expressions for the willingness to pay for quality-adjusted life-years (QALYs). The willingness to pay for QALYs depends on wealth, remaining life expectancy, health status, and the possibilities for intertemporal substitution of consumption. (C) 1999 Elsevier Science B.V. All rights reserved.

The last glacial cycle from the humid tropics of northeastern Australia: comparison of a terrestrial and a marine record

A detailed pollen record from the Ocean Drilling Program Site 820 core, located on the upper part of the continental slope off the coast of northeast Queensland, was constructed to compare with the existing pollen record from Lynch's Crater on the adjacent Atherton Tableland and allow the production of a regional picture of vegetation and environmental change through the last glacial cycle. Some broad similarities in patterns of vegetation change are revealed, despite the differences between sites and their pollen catchments, which can be related largely to global climate and sea-level changes. The original estimated time scale of the Lynch's Crater record is largely confirmed from comparison with the more thoroughly dated ODP record. Conversely, the Lynch's Crater pollen record has assisted in dating problematic parts of the ODP record. In contrast to Lynch's Crater, which reveals a sharp and sustained reduction in drier araucarian forest around 38,000 yrs BP, considered to have been the result of burning by Aboriginal people, the ODP record indicates, most likely, a stepwise reduction, dating from 140,000 yrs BP or beyond. The earliest reduction shows lack of a clear connection between Araucaria decline and increased burning and suggests that people may not have been involved at this stage. However, a further decline in araucarian forest, possibly around 45,000 yrs BP, which has a more substantial environmental impact and is not related to a time of major climate change, is likely, at least partially, the result of human burning. The suggestion, from the ODP core oxygen isotope record, of a regional sea-surface temperature increase of around 4 degrees C between about 400,000 and 250,000 yrs BP, may have had some influence on the overall decline in Araucaria and its replacement by sclerophyll vegetation. (C) 2000 Elsevier Science B.V. All rights reserved.

FHA domain boundaries of the Dun1p and Rad53p cell cycle checkpoint kinases

Dun1p and Rad53p of the budding yeast Saccharomyces cerevisiae are members of a conserved family of cell cycle checkpoint protein kinases that contain forkhead-associated (FHA) domains. Here, we demonstrate that these FHA domains contain 130-140 residues, and are thus considerably larger than previously predicted by sequence comparisons (55-75 residues), In vivo, expression of the proteolytically defined Dun1p FHA domain, but not a fragment containing only the predicted domain boundaries, inhibited the transcriptional induction of repair genes following replication blocks, This indicates that the non-catalytic FI-IA domain plays an important role in the transcriptional function of the Dun1p protein kinase. (C) 2000 Federation of European Biochemical Societies.

Resistance to temperature extremes between and within life cycle stages in Drosophila serrata, D-birchii and their hybrids: intraspecific and interspecific comparisons

Intraspecific Drosophila studies suggest that resistance to heal and cold stresses are largely independent and that correlations across life cycle stages are low whereas comparisons of Drosophila species indicate correlations between heat and cold resistance as well as between resistance levels in different life cycle stages. These inconsistent results may reflect differences in associations among traits at the interspecific and intraspecific levels or interspecific correlations arising because of correlated selection pressures. These alternatives were tested using Drosophila serrata, D. birchii and hybrids derived from these species. Variation among hybrid lines and families was used to test associations at the interspecific level while intraspecific variation was examined using isofemale lines of D. serrata. There was a significant association between adult heat knockdown time at 38 degreesC and adult cold resistance in one set of hybrid lines. An association between female knockdown resistance to heat and larval heat resistance was also evident in one set of hybrids. Resistance to heat anti cold at the larval stage were not correlated at either the intraspecific or interspecific levels. At the intraspecific level, lan al heat resistance and two measures of adult heat resistance were uncorrelated. Moreover, adult and larval cold resistance measures were not correlated at either the intraspecific or interspecific levels. These results suggest that there are no associations between resistance to heat and cold extremes and that extreme temperature resistance is largely independent across life cycle stages at both the intraspecific and interspecific levels. Species associations may therefore arise from correlated selection pressures rather than trait correlations. (C) 2000 The Linnean Society of London.