Genotoxic activity of 1,2,3‐triazolyl modified furocoumarins and 2,3‐dihydrofurocoumarins

The furocoumarin backbone is a promising platform for chemical modifications aimed at creating new pharmaceutical agents. However, the high level of biological activity of furocoumarins is associated with a number of negative effects. For example, some of the naturally occurring ones and their derivatives can show genotoxic and mutagenic properties as a result of their forming crosslinks with DNA molecules. Therefore, a particularly important area for the chemical modification of natural furocoumarins is to reduce the negative aspects of their bioactivity. By studying a group of 21 compounds—1,2,3‐triazolyl modified derivatives of furocoumarin and peucedanin—using the SOS chromotest, the Ames test, and DNA‐comet assays, we revealed modifications that can neutralize the structure's genotoxic properties. Theoretical aspects of the interaction of the compound library were studied using molecular modeling and this identified the leading role of the polyaromatic molecular core that takes part in stacking‐interactions with the pi‐systems of the nitrogenous bases of DNA.     

Parameterization of the stomatal component of the DO3SE model for Mediterranean evergreen broadleaf species

An ozone (O3) deposition model (DO3SE) is currently used in Europe to define the areas where O3 concentrations lead to absorbed O3 doses that exceed the flux-based critical levels above which phytotoxic effects would be likely recorded. This mapping exercise relies mostly on the accurate estimation of O3 flux through plant stomata. However, the present parameterization of the modulation of stomatal conductance (g(s)) behavior by different environmental variables needs further adjustment if O3 phytotoxicity is to be assessed accurately at regional or continental scales. A new parameterization of the model is proposed for Holm oak (Quercus ilex), a tree species that has been selected as a surrogate for all Mediterranean evergreen broadleaf species. This parameterization was based on a literature review, and was calibrated and validated using experimentally measured data of g(s) and several atmospheric and soil parameters recorded at three sites of the Iberian Peninsula experiencing long summer drought, and very cold and dry winter air (El Pardo and Miraflores) or milder conditions (Tietar). A fairly good agreement was found between modeled and measured data (R2 = 0.64) at Tietar. However, a reasonable performance (R2 = 0.47-0.62) of the model was only achieved at the most continental sites when g(s) and soil moisture deficit relationships were considered. The influence of root depth on g(s) estimation is discussed and recommendations are made to build up separate parameterizations for continental and marine-influenced Holm oak sites in the future.     

Proteoglycan fragmentation and respiratory mechanics in mechanically ventilated healthy rats.

This research investigated whether stretching of lung tissue due to increased positive alveolar pressure swings during mechanical ventilation (MV) at various tidal volumes (V(T)) might affect the composition and/or structure of the glycosaminoglycan (GAG) components of pulmonary extracellular proteoglycans. Experiments were performed in 30 healthy rats: 1) anesthetized and immediately killed (controls, C-0); 2) anesthetized and spontaneously breathing for 4 h (C-4h); and 3) anesthetized, paralyzed, and mechanically ventilated for 4 h with air at 0-cmH(2)O end-expiratory pressure and V(T) of 8 ml/kg (MV-1), 16 ml/kg (MV-2), 24 ml/kg (MV-3), or 32 ml/kg (MV-4), adjusting respiratory rates at a minute ventilation of 270 ml/min. Compared with C-0 and C-4h, a significant reduction of dynamic and static compliance of the respiratory system and of the lung was observed only in MV-4, while extravascular lung water significantly increased in MV-3 and MV-4, but not in MV-1 and MV-2. However, even in MV-1, MV induced a significant fragmentation of pulmonary GAGs. Extraction of covalently bound GAGs and wash out of loosely bound or fragmented GAGs progressively increased with increasing V(T) and was associated with increased expression of local (matrix metalloproteinase-2) and systemic (matrix metalloproteinase-9) activated metalloproteases. We conclude that 1) MV, even at "physiological" low V(T), severely affects the pulmonary extracellular architecture, exposing the lung parenchyma to development of ventilator-induced lung injury; and 2) respiratory mechanics is not a reliable clinical tool for early detection of lung injury.     

Effects of different immunolabeling techniques on the detection of small-cell lung cancer cells in bone marrow.

Recent reports have suggested that the immunodetection of tumor cells in bone marrow of small-cell lung cancer (SCLC) patients is by far more effective than traditional cytohistological methods and that this may be clinically relevant. This study aimed to evaluate whether the level of detection of tumor cells in bone marrow is affected by different immunostaining methods. Using two anti-NCAM monoclonal antibodies (MAbs), we compared four different "sandwich" methods on cytospin preparations of the N592 human SCLC cell line and of bone marrow aspirates from 37 SCLC patients. Our data indicate that the combination of the alkaline phosphatase-anti-alkaline phosphatase and streptavidin-biotin-alkaline phosphatase complex methods provides the best results in terms of sensitivity and specificity, and of intensity of immunoreaction and absence of staining background. Moreover, bone marrow micrometastases detected by this method were prognostically relevant and identified, among patients with apparently limited disease according to conventional staging procedures, a subgroup with shorter survival. We suggest that the choice of a sensitive immunostaining technique may significantly increase the detection rate of SCLC cells in bone marrow, mirroring the biological aggressiveness of the disease.     

Nutritional Requirements of <Emphasis Type="Italic">Lactobacillus delbrueckii</Emphasis> subsp. <Emphasis Type="Italic">lactis</Emphasis> in a Chemically Defined Medium

This study was undertaken to determine the nutritional requirements of Lactobacillus delbrueckii subsp. lactis and to develop a minimal chemically defined medium that supports sustained growth of these microorganisms. The single-omission technique was applied to each component of complete chemically defined medium in order to determine the nutritional requirements. L. delbrueckii subsp. lactis was prototrophic for alanine, glycine, aspartic acid, asparagine, glutamine, threonine, and proline. The lysine requirement was strain-dependent. Magnesium was the only essential oligoelement. These microorganisms also required uracil and guanine and adenine as pyrimidine and purine sources, respectively. In view of the nutritional requirements we designed a new minimal defined medium which supports sustained growth of L. delbrueckii subsp. lactis. This medium is simple and well defined, and should be preferable to complex media for conducting future biochemical, physiological, and genetic studies on L. delbrueckii subsp. lactis.     

Cloning of an olfactory sensory neuron-specific protein in the land snail (Eobania vermiculata)

We have isolated a gene encoding for an olfactory sensory neuron (OSN)-specific protein in an invertebrate, the land snail Eobania vermiculata (GenBank accession number AY147909). Using in situ hybridization, we detected expression of its mRNA in the dendrite, cell body and axon of OSNs. By neural tracing, using the lipophilic tracer DiI and in situ hybridization, we have revealed the organization of OSNs and their connections with olfactory glomeruli in the land snail. Sequence and expression pattern analogy of land snail protein with olfactory marker protein (OMP) from vertebrates suggest that the land snail protein is an OMP-like protein. This protein could represent a plesiomorphic character in the evolution of olfactory proteins.