Acylation of alkyllysophospholipids by Fischer sarcoma microsomes

Acylation of alkyllysophospholipids in most cells occurs by: (a) CoA-independent transacylation, (b) CoA-dependent transacylation, and (c) acyl-CoA-dependent acylation. Using a recently developed high-performance liquid chromatography method, we have investigated the factors that influence the molecular species composition of the acylated products formed via these pathways with 1-hexadecyl-2-lyso-sn-glycero-3-phosphocholine (alkyllyso-GPC) or 1-hexadecyl-2-lyso-sn-glycero-3-phospho-ethanolamine (alkyllyso-GPE) as substrates for the enzymes in Fischer R-3259 sarcoma microsomes. We found that short incubation times and low substrate concentrations favored the formation of polyunsaturated molecular species, i.e., 16:0-22:6, 16:0-22:5 (n - 3), and 16:0-20:4. Also, in agreement with results from other systems, CoA-independent transacylation produced a high percentage of polyunsaturated molecular species; acyl-CoA-dependent acylations generated the least polyunsaturated molecular species and CoA-dependent transacylation gave intermediate values. Furthermore, no substrate selectivity occurred with respect to alkyl chain lengths of alkyllyso-GPE; similar molecular species composition was obtained with either hexadecyllyso-GPE or octadecyllyso-GPE as substrates. Responses to N-ethylmaleimide inhibition and heat inactivation as well as pH optima suggest the same enzyme catalyzes the CoA-independent transacylation of both alkyllyso-GPC and alkyllyso-GPE.     

N-aryl-piperidine-4-carboxamides as a novel class of potent inhibitors of MALT1 proteolytic activity

Starting from a weak screening hit, potent and selective inhibitors of the MALT1 protease function were elaborated. Advanced compounds displayed high potency in biochemical and cellular assays. Compounds showed activity in a mechanistic Jurkat T cell activation assay as well as in the B-cell lymphoma line OCI-Ly3, which suggests potential use of MALT1 inhibitors in the treatment of autoimmune diseases as well as B-cell lymphomas with a dysregulated NF-κB pathway. Initially, rat pharmacokinetic properties of this compound series were dominated by very high clearance which could be linked to amide cleavage. Using a rat hepatocyte assay a good in vitro-in vivo correlation could be established which led to the identification of compounds with improved PK properties.     

Seed‐induced Aβ deposition is modulated by microglia under environmental enrichment in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is characterized by severe neuronal loss as well as the accumulation of amyloid‐β (Aβ), which ultimately leads to plaque formation. Although there is now a general agreement that the aggregation of Aβ can be initiated by prion‐like seeding, the impact and functional consequences of induced Aβ deposits (Aβ seeding) on neurons still remain open questions. Here, we find that Aβ seeding, representing early stages of plaque formation, leads to a dramatic decrease in proliferation and neurogenesis in two APP transgenic mouse models. We further demonstrate that neuronal cell death occurs primarily in the vicinity of induced Aβ deposits culminating in electrophysiological abnormalities. Notably, environmental enrichment and voluntary exercise not only revives adult neurogenesis and reverses memory deficits but, most importantly, prevents Aβ seeding by activated, phagocytic microglia cells. Our work expands the current knowledge regarding Aβ seeding and the consequences thereof and attributes microglia an important role in diminishing Aβ seeding by environmental enrichment.     

A replication-competent, endogenous retrovirus from an aged DBA/2 mouse contains the complete env from Emv-3 and a novel gag partially related to AKT-8.

We previously described an endogenous murine retrovirus, rv-DBA/2aged, isolated from an aged DBA/2 mouse. The previous report showed that a recombination which resulted in the replacement of Emv-3 gag sequences with gag sequences homologous to those found in the AKT-8 virus had taken place. This recombination allowed production of a competent virus from the defective Emv-3 locus. However, the extent of replacement of Emv-3 gag was not known. We report here the entire sequence for the gag gene of rv-DBA/2aged as well as the previously unsequenced 3' end of the Emv-3 gag gene. These data demonstrate that while sequences homologous to the entire gag gene fragment found in AKT-8 are represented in rv-DBA/2aged, the remainder of rv-DBA/2aged gag is not derived from Emv-3 but is a unique gag sequence. Furthermore, a complete comparison of env sequences shows that the env of rv-DBA/2aged is derived entirely from Emv-3. Additional data suggest that the recombination which led to production of the rv-DBA/2aged virus may be a common event in aging DBA/2 mice. Finally, comparison of the new sequences of Emv-3 with those of the Akv virus (also designated AKR-623 and Emv-11) and Emv-1 shows that this endogenous virus locus is very closely related to the other Emv loci at the nucleotide sequence level.     

Chitin: a potential new alternative nitrogen source for the tertiary,algal-based treatment of pulp and paper mill wastewater

Every day, pulp and paper mills in the USA discharge millions of liters of wastewater. Primary and secondary treatment of this wastewater often enriches it with phosphorus, resulting in uncontrolled eutrophication of receiving water bodies. A new method of tertiary wastewater treatment uses controlled growth of algae in a photobioreactor to sequester phosphorus into algal biomass, which is then harvested. This typically requires addition of a nitrogen fertilizer (nitrate, ammonium, or urea) to the water. We show on the laboratory scale that chitin can be used as an alternative source of nitrogen for the tertiary treatment of pulp mill wastewater using algae. We demonstrate that phosphorus can be efficiently removed from pulp wastewater using algae and chitin. Furthermore, phosphorus removal with chitin did not result in an increase in dissolved nitrogen in the wastewater because it is insoluble, unlike conventional nitrogen fertilizers. Despite its insolubility, it has recently been found that many diverse algae and cyanobacteria can use it as a source of nitrogen. Chitin has many advantages over conventional nitrogen fertilizers for use in wastewater treatment technologies. It is the second-most abundant natural polymer and is a waste product of the shellfish industry. Chitin is sustainable, inexpensive, and carbon neutral. Thus, chitin improves the sustainability and carbon footprints associated with water treatment, while the production of commercially attractive algal biomass helps to offset costs associated with the water treatment system itself.     

Congenic Strains Confirm the Pleiotropic Effect of Chromosome 4 QTL on Mouse Femoral Geometry and Biomechanical Performance

A pleiotropic quantitative trait locus (QTL) for bone geometry and mechanical performance in mice was mapped to distal chromosome 4 via an intercross of recombinant congenic mice HcB-8 and HcB-23. To study the QTL in isolation, we have generated C3H.B10-(rs6355453-rs13478087) (C.B.4.3) and C3H.B10-(rs6369860-D4Mit170) (C.B.4.2) congenic strains that harbor ~20 Mb and ~3 Mb, respectively, of chromosome 4 overlapping segments from C57BL/10ScSnA (B10) within the locus on a C3H/DiSnA (C3H) background. Using 3-point bend testing and standard beam equations, we phenotyped these mice for femoral mid-diaphyseal geometry and biomechanical performance. We analyzed the results via 2-way ANOVA, using sex and genotype as factors. In the C.B.4.3 strain, we found that homozygous B10/B10 male mice had smaller cross sectional area (CSA) and reduced total displacement than homozygous C3H/C3H mice. Sex by genotype interaction was also observed for maximum load and stiffness for C3H/C3H and B10/B10 mice, respectively. In C.B.4.2 strain, we found that homozygous B10/B10 mice had lower total displacement, post-yield displacement (PYD), stiffness, yield load and maximum load than mice harboring C3H allele. Sex by genotype interaction was observed in B10/B10 mice for perimeter, outer minor axis (OMA) and CSA. There were no significant differences in tissue level mechanical performance, which suggest that the QTL acts primarily on circumferential bone size. These data confirm the prior QTL mapping data and support other work demonstrating the importance of chromosome 4 QTL on bone modeling and bone responses to mechanical loading.     

Intramural distribution of immunoreactive vasoactive intestinal polypeptide (VIP), substance P,somatostatin and mammalian bombesin in the oesophago-gastro-pyloric region of the human gut

Summary The intramural distribution of vasoactive intestinal polypeptide (VIP), substance P, somatostatin and mammalian bombesin was studied in the oesophago-gastro-pyloric region of the human gut. At each of 21 sampling sites encompassing this entire area, the gut wall was separated into mucosa, submucosa and muscularis externa, and extracted for radioimmunoassay. VIP levels in the mucosa were very high in the proximal oesophagus (1231±174 pmol/g, mean±SEM) and showed varied, but generally decreasing concentrations towards the stomach, followed by a clear-cut increase across the pyloric canal (distal antrum: 73±16 pmol/g, proximal duodenum: 366±62 pmol/ g); consistent levels were found in submucosa and muscle (200–400 pmol/g) at most sites, the stomach again showing lower concentrations. By contrast, substance P was present in small amounts as far as the proximal stomach, but sharply increased across the pyloric canal, especially in mucosa and submucosa (distal antrum: 20±6.5 and 5.5±1.3 pmol/g; proximal duodenum: 62±8.5 and 34±11 pmol/g, respectively). Somatostatin concentrations were very low in the mucosa of the oesophagus and stepwise increased in the cardiac, mid-gastric and pyloric mucosa (cardia: 224±72 pmol/g; distal antrum: 513±152 pmol/g; proximal duodenum: 1013±113 pmol/g); concentrations in the submucosa and muscularis were generally low, with the exception of antrum and duodenum. Mammalian bombesin was comparatively well represented throughout the oesophageal muscularis (5–8 pmol/g), but most abundant in the stomach in all layers (oxyntic mucosa: 24±2.7 pmol/g; submucosa: 20±5.7 pmol/g; muscle: 28±5.0 pmol/g). In conclusion, a distinct differential distribution of the four peptides studied was revealed, indicating a diffuse, but highly differentiated peptide-containing innervation of the proximal human gut.     

Incorporation and subcellular distribution of an unnatural phospholipid base-analog, N-isopropyl-ethanolamine, in rat liver.

An unnatural phospholipid, phosphatidyl-N-isopropylethanolamine, was isolated from rat liver after intraperitoneal injections of N-isopropylethanol-amine; it was identified on the basis of enzymic, chemical, and chromatographic analyses. Although this phospholipid was formed at the expense of phosphatidylcholine and phosphatidylethanolamine, its fatty acid composition did not resemble either of these lipids. Microsomes, mitochondria, and plasma membranes contained significant amounts (up to 9%) of this unusual phospholipid. Radioisotope incorporation experiments suggest that the N-isopropylethanol-amine containing phospholipid is rapidly equilibrated between microsomes and mitochondria and more slowly with surface membranes.     

Metabolically active glucosides in oleaceae seeds: I. The effects of germination, growth, and hormone treatments

The seeds of six woody species of Oleaceae representing three genera, contain high concentrations of water-soluble glucosides, with major absorption maxima below 240 nanometers. In Fraxinus americana seeds three of these compounds, designated GL-3, GL-5, and GL-6, account for almost 10% of the dry weight. They are found in the endosperm and embryo but not in the pericarp. While the level of GL-5 is not particularly influenced by the physiological state of the embryo, that of GL-3 and GL-6 decreases as a result of germination and growth during a 10-day period. As the concentrations of GL-3 and GL-6 decrease, new ultraviolet-absorbing compounds are formed. The changes in the concentration of the ultraviolet-absorbing glucosides during cold temperature after-ripening, prior to germination, are small. When germination of dormant embryos is induced with gibberellic acid, the concentrations of GL-3 and GL-6 decrease in a manner similar to that observed with nondormant embryos. In the presence of abscisic acid no losses of GL-3 and GL-6 were observed. It is suggested that GL-3 and GL-6 fulfill some definite functions in the germination and growth of F. americana embryos, and that gibberellic acid and abscisic acid can exert a regulatory effect on the metabolism of these glucosides.