Superoxide dismutase is upregulated in <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> following protoporphyrin-mediated photodynamic inactivation and does not directly influence the response to photodynamic treatment

Background  

Staphylococcus aureus, a major human pathogen causes a wide range of disease syndromes. The most dangerous are methicillin-resistant S. aureus (MRSA) strains, resistant not only to all β-lactam antibiotics but also to other antimicrobials. An alarming increase in antibiotic resistance spreading among pathogenic bacteria inclines to search for alternative therapeutic options, for which resistance can not be developed easily. Among others, photodynamic inactivation (PDI) of S. aureus is a promising option. Photodynamic inactivation is based on a concept that a non toxic chemical, called a photosensitizer upon excitation with light of an appropriate wavelength is activated. As a consequence singlet oxygen and other reactive oxygen species (e.g. superoxide anion) are produced, which are responsible for the cytotoxic effect towards bacterial cells. As strain-dependence in photodynamic inactivation of S. aureus was observed, determination of the molecular marker(s) underlying the mechanism of the bacterial response to PDI treatment would be of great clinical importance. We examined the role of superoxide dismutases (Sod) in photodynamic inactivation of S. aureus as enzymes responsible for oxidative stress resistance.     

SuperSAGE analysis of the <Emphasis Type="Italic">Nicotiana attenuata</Emphasis> transcriptome after fatty acid-amino acid elicitation (FAC): identification of early mediators of insect responses

Background  

Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown.     

Study of Poaceae phenology in a Mediterranean climate. Which species contribute most to airborne pollen counts?

The present study sought to determine which of the common Poaceae species in the study area contribute most to the Poaceae pollen season curve, and to determine the phenological behaviour of the species studied. The different floral phenophases in thirty-three Poaceae species common in and around the city of Córdoba (SW Iberian Peninsula) were checked periodically over the period 2004–2006. Results showed that longer phenological ranges were recorded in the coolest and wettest year, and shorter ranges in the warmest and driest year. Moreover, ranges varied as a function of altitude: populations in lower-lying areas flowered earlier than those at higher altitudes. The results, taken in conjunction with the findings of preliminary research into potential pollen production, showed that probably only four of the Poaceae species studied—Dactylis glomerata, Lolium rigidum, Trisetaria panicea and Vulpia geniculata—were major contributors to the Poaceae airborne pollen curve.     

Taxonomic distribution and origins of the extended LHC (light-harvesting complex) antenna protein superfamily

Background  

The extended light-harvesting complex (LHC) protein superfamily is a centerpiece of eukaryotic photosynthesis, comprising the LHC family and several families involved in photoprotection, like the LHC-like and the photosystem II subunit S (PSBS). The evolution of this complex superfamily has long remained elusive, partially due to previously missing families.     

Properties of herpes simplex virus type 1 and type 2 DNA polymerase

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) DNA polymerases were highly purified from infected HeLa BU cells by DEAE cellulose, phosphocellulose and DNA cellulose column chromatography. DNA exonuclease activity but not endonuclease activity was found associated with both types of DNA polymerase. Both DNA polymerase activities could be activated by salt in a similar fashion with the optimal activity in the range of ionic strength between 0.22 and 0.29 alpha. At an ionic strength of 0.14, spermidine and putrescine in the concentration range (0--5 mM) studied could mimic the action of KCI in stimulating DNA polymerase activity. Spermine, in the same concentration range, had a biphasic effect. At an ionic strength of 0.29 all three polyamines were inhibitory. HSV-1 and HSV-2 DNA polymerase are similar in their column chromatographic behavior, sedimentation rate in sucrose gradient centrifugation, and activation energy, but they differ in their heat stability at 45 degrees C with the HSV-2 enzyme more stable than the HSV-1 enzyme. Kinetic behavior of both enzymes is similar, with Km values for deoxyribonucleoside triphosphates in the range of 5 . 10(-7) to 1.8 . 10(-8) M. IdUTP and dUTP served as apparent competitive inhibitors with respect to dTTP, and AraATP acted as an apparent competitive inhibitor with respect to dATP. AraATP could not replace dATP in the DNA polymerization reaction; in contrast, IdUTP could replace TTP. Phosphonoformic acid behaved as an uncompetitive inhibitor with respect to DNA. The ID(50) value estimated was foind to be dependent on the purity of the DNA polymerase used and the ionic strength of the assay condition. Each DNA-polymerase associated DNA exonuclease had the same stability at 45 degrees C as its DNA polymerase. The associated DNAase activity was inhibited by phosphonoformic acid and high ionic strength of the assay condition.     

Cytological and mapping analysis of a novel male sterile type resulting from spontaneous floral organ homeotic conversion in marigold (<Emphasis Type="Italic">Tagetes erecta</Emphasis> L.)

A male sterile line was isolated in marigold (Tagetes erecta L.) and cytological analysis determined this to be a novel genic male sterility trait (Tems). Through the use of amplified fragment length polymorphisms (AFLPs) and bulked segregant analysis (BSA), tightly linked markers of Tems were identified with a view towards a map-based cloning strategy. It was found that spontaneous homeotic conversion of floral organs was the underlying cause of the male sterility in this marigold line. Thus, petals of male sterile plants resembled sepal-like structures and the stamens were partially converted to styles, although without the full characteristics or function of the true style organs. We have constructed a fine marker-based map for the Tems gene. This is intended to provide a tool for marker assisted selection (MAS) strategies in hybrid breeding and map-based cloning strategies for the male sterility locus. We discuss the significance of this spontaneously derived genic male sterility trait relating to the homeotic conversion of floral organs in marigold.     

It’s a knockout: CCN3 suppresses neointimal thickening

The role of CCN proteins in vivo is only just becoming understood. A prototypical member of the CCN family, CCN3 suppresses proliferation. In a study in press, Shimoyama and colleagues show that mice lacking CCN3 have a hyperproliferative response to vascular injury. These data, along with other recent observations, suggest that CCN3 may represent a novel therapy for hyperproliferative diseases.