Microphytobenthic biomass assessment by pigment analysis: comparison of spectrophotometry and High Performance Liquid Chromatography methods

Samples of microphytobenthos from the Tagus estuary were analysed for photosynthetic pigments by spectrophotometry and High Performance Liquid Chromatography (HPLC). Chlorophyll a values obtained with HPLC and spectrophotometry methods presented a highly significant positive correlation for both spectrophotometric methods used (with and without the correction for pheopigments), but this relationship depended on the type of sediment. We concluded that spectrophotometric methods give reliable Chl-a values, being suited for routine analysis, when a vast number of replicates is needed. However, for the correct estimation of pheopigments, HPLC analysis is indispensable. In the literature, Chl-a estimations are expressed per content (μg g⁻¹) or concentration (mg m⁻²). We discuss the influence of sediment type on the results depending on the type of unit used, and propose a simple conversion factor based on sediment water content.     

Synthesis and in vitro anti Mycobacterium tuberculosis activity of a series of phthalimide derivatives

New phthalimide derivatives were easily prepared through condensation of phthalic anhydride and selected amines with variable yields (70–90%). All compounds (3a–l) were evaluated against Mycobacterium tuberculosis H₃₇Rv using Alamar Blue susceptibility. The compounds 3c, 3i, and 3l have the minimum inhibitory concentrations (MICs) of 3.9, 7.8, and 5.0 μg/mL, respectively, and could be considered new lead compounds in the treatment of tuberculosis and multi-drug resistant tuberculosis.     

Induction of SerpinB2 and Th1/Th2 Modulation by SerpinB2 during Lentiviral Infections In Vivo

SerpinB2, also known as plasminogen activator inhibitor type 2, is a major product of activated monocytes/macrophages and is often strongly induced during infection and inflammation; however, its physiological function remains somewhat elusive. Herein we show that SerpinB2 is induced in peripheral blood mononuclear cells following infection of pigtail macaques with CCR5-utilizing (macrophage-tropic) SIV_mac239, but not the rapidly pathogenic CXCR4-utilizing (T cell-tropic) SHIV_mn229. To investigate the role of SerpinB2 in lentiviral infections, SerpinB2^−/− mice were infected with EcoHIV, a chimeric HIV in which HIV gp120 has been replaced with gp80 from ecotropic murine leukemia virus. EcoHIV infected SerpinB2^−/− mice produced significantly lower anti-gag IgG1 antibody titres than infected SerpinB2^+/+ mice, and showed slightly delayed clearance of EcoHIV. Analyses of published microarray studies showed significantly higher levels of SerpinB2 mRNA in monocytes from HIV-1 infected patients when compared with uninfected controls, as well as a significant negative correlation between SerpinB2 and T-bet mRNA levels in peripheral blood mononuclear cells. These data illustrate that SerpinB2 can be induced by lentiviral infection in vivo and support the emerging notion that a physiological role of SerpinB2 is modulation of Th1/Th2 responses.     

Localization of Endo-Oligopeptidase (EC 3.4.22.19) in the Rat Nervous Tissue

The subcellular and regional distribution of endo-oligopeptidase (EC 3.4.22.19), an enzyme capable of generating enkephalin by single cleavage from enkephalin-containing peptides, was determined by an enzymatic assay using metorphamide and by immunochemical techniques in the CNS of the rat. The rat CNS contains a membrane-associated form of endo-oligopeptidase, an enzyme predominantly associated with the soluble fraction of brain homogenates. Subcellular fractionation showed that approximately 17% of the total activity of the enzyme is associated with membrane fractions including synaptosomes. Synaptosomal membranes were prepared from neocortex, striatum, hypothalamus, medulla, spinal cord, and cerebellum. The amount of EC 3.4.22.19 activity solubilized by 3-[( 3-cholamidopropyl]dimethylammonio)-1-propanesulfonate from synaptosomal membranes was similar in neocortex, striatum, and hypothalamus, being three- to 10-fold greater than in spinal cord, cerebellum, and medulla. A polyclonal antibody exhibiting high affinity for endo-oligopeptidase was raised in rabbits against the purified rat brain enzyme and used to localize endo-oligopeptidase by Western blotting and by immunoperoxidase techniques. A strong band corresponding to the Mr of EC 3.4.22.19 was found in solubilized proteins obtained from synaptosomal membranes prepared from hypothalamus, neocortex, and striatum when subjected to Western blotting. The immunohistochemical localization of endo-oligopeptidase indicated that the immunoreactivity was confined to gray matter in regions known to be rich in peptide-containing neurons such as the striatum. In the cerebellum, a region poor in peptides, no staining could be detected. The nonuniform distribution of endo-oligopeptidase in rat brain suggests a role in neurotransmitter processing in the CNS.     

Distribution and fine structure of ependymal cells possessing intracellular cysts in the aqueductal wall of the rat brain

Summary The wall of the cerebral aqueduct was examined in 20 male rats at the light- and electron-microscopic levels. Disorder in ciliary orientation was occasionally seen in ordinary ependymal cells. Ependymal cells possessing intracellular cysts of 5 to 30 urn in diameter were observed within and beneath the aqueductal ependyma in all animals examined. Light-microscopic reconstruction from serial, 10-m thick frontal sections revealed an extensive distribution of cystic ependymal cells (CECs), especially along the ependymal ridges in the rostral half of the aqueduct, and along the dorsal region of the aqueductal lining in the caudal half. Both cystic and surface membranes of CECs bore microvilli and cilia. Ectopic ependymal cells (EECs) characterized by densely packed microvilli, well-developed intermediate junctions and cilia, but without cysts, were situated in the subependymal region adjacent to a CEC or another EEC. The ependymal ridges were long, narrow and sporadically stratified ependymal linings extending rostrocaudally and bilaterally along the aqueductal surface. Tanycyte-like cells filled the surface region of the ridge, and CECs and EECs were frequently seen in the core. Intraventricularly injected microperoxidase was detected among densely packed microvilli but not in the cystic lumina of CECs, indicating that EECs and CECs are distinct entities.