Chlorophyll differences in Mono Lake (California) observable on Landsat imagery

In Mono Lake (California), a large saline lake, chlorophyll concentrations in the euphotic zone increased from 4 to 45 µg l^–1 between July and October 1979. These seasonal changes in chlorophyll are detectable on imagery obtained with the multispectral scanner on Landsat. Computer-compatible tapes of Landsat images were normalized for solar zenith and corrected for atmospheric scatter and absorption to obtain Landsat band 4 emittances (W m^–2 str^–1) of 13.4 ± 0.5 when chlorophyll was 4 µg l^–1 and 4.6 ± 0.3 when chlorophyll was 45 µg l^–1. Lake wide, spatial heterogeneity of chlorophyll of 2 µg l^–1 in July and 8 µg l^–1 in October was not detectable on the Landsat imagery.     

Hexane-solubilised reaction centre proteolipid complexes of Rhodopseudomonas sphaeroides

Reaction centres from Rhodopseudomonas sphaeroides, strain R-26, have been solubilised in hexane by the use of phospholipids and cations. Two procedures have been developed: (I) a two-step technique involving the formation of detergent-free proteoliposomes from detergent solubilised reaction centres and phospholipids and mixing these with hexane in the presence of cations; (II) directly sonicating detergent-solubilised reaction centres with phosopholipids before mixing with hexane and cations.The yield of the extracted complex varied with the ratios of protein, phospholipid and cations, species of phospholipid, and sonication time. The spectral characteristics of the complex in the organic phase were similar to those of detergent-solubilised reaction centres. The stability of the reaction centres appeared to be dependent on the presence of phospholipid and water in the hexane. The usefulness of the hexane solution as a model membrane system is discussed and its possible future applications are considered.     

Adherence and invasion of avian pathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> to avian tracheal epithelial cells

Avian septicemia is a systemic disease where bacteria attach and invade the avian respiratory tract and enter the bloodstream and vital organs. Avian pathogenic Escherichia coli (APEC) cause this extraintestinal disease utilizing several virulence factors that have been identified. Adhesion to the trachea is the critical initial step for septic APEC pathogenicity. We investigated the ability of APEC to associate with models of tracheal epithelium. The microorganism was able to adhere to an avian tracheal explant model of infection. In addition, a primary cell culture, derived from chicken tracheal epithelium, was developed and demonstrated the ability of APEC to attach to and invade avian tracheal cells in vitro. These results are compatible with the nature of the disease and are important to the understanding of the initial point of entry of APEC in the avian model of septic infections.     

Solid state fermentation reactors: from lab scale to pilot plant

Relatively many workers in the world are studying different aspects in SSF processes but few are working on reactor design and scale-up. From about 10 years, we are developing reactors from lab scale to pilot plant, based on the same technology, reactor design and flowsheet to allow fermentation with a deep layer (up to 1 m in the pilot plant). These reactors have all a forced aeration and the possibility or not to agitate. Regulations of temperature and water content of the culture are monitored by a special device.     

Aminolysis of 2-hydroxy esters catalyzed by Candida antarctica lipase

Candida antarctica lipase catalyzed the aminolysis of 2-hydroxy esters with amines in organic solvents to yield the corresponding 2-hydroxy amides. The reactions proceeded at 28–30 °C in dioxane for 6 h with 3 mM substrates with yields ranging between 45% (w/w) (for branched substrates) to 88% (w/w) (for linear substrates). Although the reaction was not enantioselective, because of its simplicity it represents an alternative method for the synthesis of functionalised amides.     

Effect of Natural and Semisynthetic Pseudoguianolides on the Stability of NF-κB:DNA Complex Studied by Agarose Gel Electrophoresis

The nuclear factor κB (NF-κB) is a promising target for drug discovery. NF-κB is a heterodimeric complex of RelA and p50 subunits that interact with the DNA, regulating the expression of several genes; its dysregulation can trigger diverse diseases including inflammation, immunodeficiency, and cancer. There is some experimental evidence, based on whole cells studies, that natural sesquiterpene lactones (Sls) can inhibit the interaction of NF-κB with DNA, by alkylating the RelA subunit via a Michael addition. In the present work, 28 natural and semisynthetic pseudoguianolides were screened as potential inhibitors of NF-κB in a biochemical assay that was designed using pure NF-κB heterodimer, pseudoguianolides and a ~1000 bp palindromic DNA fragment harboring two NF-κB recognition sequences. By comparing the relative amount of free DNA fragment to the NF-κB – DNA complex, in a routine agarose gel electrophoresis, the destabilizing effect of a compound on the complex is estimated. The results of the assay and the following structure-activity relationship study, allowed the identification of several relevant structural features in the pseudoguaianolide skeleton, which are necessary to enhance the dissociating capacity of NF-κB–DNA complex. The most active compounds are substituted at C-3 (α-carbonyl), in addition to having the α-methylene-γ-lactone moiety which is essential for the alkylation of RelA.     

The history,taxonomy, and geographic origins of an introduced African monkey in the southeastern United States

Primates - The origins and taxonomy of the introduced vervet monkey population in Dania Beach, Florida has been unconfirmed due to a lack of documentation and genetic research. Our goal was to...