Structural and physiological features of sterols necessary to satisfy bulk membrane and sparking requirements in yeast sterol auxotrophs

A variety of sterols and stanols have been analyzed for their ability to satisfy bulk membrane and high-specificity (sparking) functions in three yeast sterol auxotrophs. While many sterols and stanols satisfied bulk membrane requirements, only those possessing a C-5,6 unsaturation or capable of being desaturated at C-5 fulfilled the high-specificity sparking requirement. Unsaturation of the A-ring or beta-saturation of a C-5,6 double bond rendered both sterol and stanol unsuitable for either function. The C-28 methyl group of ergosterol, while not required for growth, allowed for greater ease of desaturation at C-5 in vivo. As a result some sterols and stanols lacking the C-28 methyl were incapable of satisfying the sparking requirement while identical compounds possessing the C-28 methyl were able to fulfill the sparking function(s). These data are extended to hypothesize a role for the C-28 methyl group of ergosterol in yeast.     

Existence and significance of Acartia grani resting eggs (Copepoda: Calanoida) in sediments of a coastal station in the Alboran Sea (SE Spain)

The seasonal abundance of copepod eggs in bottom sediments ofMalaga harbour was documented during an annual cycle betweenJune 1989 and June 1990. The concentration noted ranged from6.6.10⁶ to 0.1910⁶ m^–2. The number of adults in thewater column and eggs recovered from the bottom sediments fluctuatedmarkedly with season. The highest egg abundance in sedimentswas found coincidentally with the early population growth season,although the values remained high until the adults disappearedfrom the water column. During the winter, the number of eggsdecreased until the development of the next copepod population.When bottom sediments were incubated in the laboratory, a largenumber of Acartia nauplii hatched, which showed that eggs laidin the autumn remain viable at the bottom until late spring,thus providing a large pool of potential recruits for the planktonicpopulation. ¹Present address: Departamento de Biologa Animal, Vegetal yEcologa, Facultad de Ciencias Experimentales, Universidad deMan Paraje Las Lagunillas s/n, 23071 Man, Spain     

The orosomucoid 1 protein (alpha1 acid glycoprotein) is overexpressed in odontogenic myxoma

ABSTRACT: BACKGROUND: Odontogenic myxoma (OM) is a benign, but locally invasive, neoplasm occurring in the jaws. However, the molecules implicated in its development are unknown. OM as well as Dental Follicle (DF), an odontogenic tissue surrounding the enamel organ, is derived from ectomesenchymal/mesencyhmal elements. To identify some protein that could participate in the development of this neoplasm, total proteins from OM were separated by two-dimensional electrophoresis and the profiles were compared with those obtained from DF, used as a control. RESULTS: We identified eight proteins with differential expression; two of them were downregulated and six upregulated in OM. A spot consistently overexpressed in odontogenic myxoma, with a molecular weight of 44-kDa and a pI of 3.5 was identified as the orosomucoid 1 protein. Western blot experiments confirmed the overexpression of this protein in odontogenic myxoma and immunohistochemical assays showed that this protein was mainly located in the cytoplasm of stellate and spindle-shaped cells of this neoplasm. CONCLUSION: Orosomucoid 1, which belongs to a group of acute-phase proteins, may play a role in the modulation of the immune system and possibly it influences the development of OM.     

Comparison of two birnavirus-rhabdovirus coinfections in fish cell lines

Aquabirnaviruses, such as the infectious pancreatic necrosis virus (IPNV), Novirhabdoviruses, such as the infectious hematopoiteic necrosis virus (IHNV) and the viral hemorrhagic septicemia virus (VHSV), cause considerable losses to the salmonid industry worldwide. Coinfections of 2 viruses have been described, but the interactions between rhabdoviruses and birnaviruses have not been examined closely. Using virus titration, flow cytometry and RT-PCR assays, we compared the effect of IPNV on the replication of IHNV and VHSV in tissue culture cells. RT-PCR assays indicated that simultaneous infection of IPNV with VHSV does not affect the replication of the rhabdovirus either in the first or successive passages; the infective titers were similar in single and double infections. In contrast, coinfection of IPNV with IHNV induced a fall in infectivity, with reduced expression of IHNV viral antigens in BF-2 cells from Lepomis macrochirus and a loss of 4.5 log10 units of the infective titer after 3 successive passages. It was possible to stimulate BF-2 cells to produce significant interferon-like activity against IHNV but not against VHSV.     

High glucose increases B1-kinin receptor expression and signaling in endothelial cells

The loss of endothelial function is the initiating factor in the development of diabetic vascular disease. Kinins control endothelial function by the activation of two receptors: the B2 which is constitutively expressed, and the B1 which is highly induced in pathological conditions. In the present study, we observed that the levels of B1-receptor mRNA and protein are induced in endothelial cells incubated in high glucose. An increase in B1-receptor was also observed in the endothelial layer of aortas, from 4-week diabetic rats. When cells were grown in high glucose, the B1 agonist des-Arg9-BK increased nitrite levels, whereas in normal glucose nitrite levels were unchanged. Nitrite increase was blocked by L-NAME and 1400W indicating the participation of the inducible Nitric Oxide Synthase (iNOS). iNOS protein levels were also increased in high glucose. These results demonstrate the participation of the B1 receptor in the signaling pathways mediated by kinins in high glucose.     

Synthesis and characterization of tritylthioethanamine derivatives with potent KSP inhibitory activity

Assembly of a bipolar mitotic spindle requires the action of class 5 kinesins, and inhibition or depletion of this motor results in mitotic arrest and apoptosis. S-Trityl-l-cysteine is an allosteric inhibitor of vertebrate Kinesin Spindle Protein (KSP) that has generated considerable interest due to its anti-cancer properties, however, poor pharmacological properties have limited the use of this compound. We have modified the triphenylmethyl and cysteine groups, guided by biochemical and cell-based assays, to yield new cysteinol and cysteamine derivatives with increased inhibitory activity, greater efficacy in model systems, and significantly enhanced potency against the NCI60 tumor panel. These results reveal a promising new class of conformationally-flexible small molecules as allosteric KSP inhibitors for use as research tools, with activities that provide impetus for further development as anti-tumor agents.     

Multiple functions for sterols in Saccharomyces cerevisiae

Analyses with a yeast sterol auxotroph indicated that there are at least four different levels of function for sterol which have been designated sparking, critical domain, domain and bulk. Growth of yeast sterol auxotrophs on cholestanol is precluded unless minute amounts of ergosterol are available. We have designated this phenomenon the sparking of growth, in which cholestanol satisfies an overall membrane sterol requirement and ergosterol fulfills a high specificity sparking function. The critical domain role for sterol is observed under conditions of lanosterol supplementation where low levels of ergosterol (10-times those necessary for sparking on cholestanol) are required for growth. The sterol functions designated domain and bulk are illustrated by assessing cellular free sterol levels and plasma membrane properties of a sterol auxotroph after growth on different concentrations of exogenously supplied sterol. Plasma membranes isolated from auxotrophs grown on domain or bulk levels of sterol underwent no lipid thermotropic transitions, while plasma membranes from cells grown on critical domain levels of sterol underwent a lipid thermotropic transition, when analyzed by steady-state fluorescence anisotropy.     

Discovery of imidazo[1,2-a]-, [1,2,4]triazolo[4,3-a]-, and [1,2,4]triazolo[1,5-a]pyridine-8-carboxamide negative allosteric modulators of metabotropic glutamate receptor subtype 5

Based on a hypothesis that an intramolecular hydrogen bond was present in our lead series of picolinamide mGlu₅ NAMs, we reasoned that an inactive nicotinamide series could be modified through introduction of a fused heterocyclic core to generate potent mGlu₅ NAMs. In this Letter, we describe the synthesis and evaluation of compounds that demonstrate the viability of that approach. Selected analogs were profiled in a variety of in vitro assays, and two compounds were evaluated in rat pharmacokinetic studies and a mouse model of obsessive-compulsive disorder. Ancillary pharmacology screening revealed that members of this series exhibited moderate inhibition of the dopamine transporter (DAT), and SAR was developed that expanded the selectivity for mGlu₅ versus DAT.     

Discovery and optimization of 3-(4-aryl/heteroarylsulfonyl)piperazin-1-yl)-6-(piperidin-1-yl)pyridazines as novel,CNS penetrant pan-muscarinic antagonists

This letter describes the synthesis and structure activity relationship (SAR) studies of structurally novel M₄ antagonists, based on a 3-(4-aryl/heteroarylsulfonyl)piperazin-1-yl)-6-(piperidin-1-yl)pyridazine core, identified from a high-throughput screening campaign. A multi-dimensional optimization effort enhanced potency at human M₄ (hM₄ IC₅₀s < 200 nM), with only moderate species differences noted, and with enantioselective inhibition. Moreover, CNS penetration proved attractive for this series (rat brain:plasma K_p = 2.1, K_p,uu = 1.1). Despite the absence of the prototypical mAChR antagonist basic or quaternary amine moiety, this series displayed pan-muscarinic antagonist activity across M_1-5 (with 9- to 16-fold functional selectivity at best). This series further expands the chemical diversity of mAChR antagonists.