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We introduce a true microcanonical ensemble appropriate for Monte Carlo simulations of lattice gas models in which both the energy and the number of particles are held fixed. We also deduce formulas that allow us to do the calculation of the intensive quantities: temperature and chemical potential. The numerical results coming from Monte Carlo simulations(More)
The pineal hormone melatonin (5-methoxy-N-acetyl-tryptamine) has been reported to participate in important physiological processes. Although some of its biological actions seem to depend on a protein receptor at the membrane surface, melatonin is known to interact with a large variety of tissues and cells, suggesting that the molecule may not necessarily(More)
ESR spectra of spin labels placed at the membrane surface and at different depths of the bilayer core, and melatonin fluorescence in the presence of lipid vesicles, suggest an average shallow position for the hormone in the membrane. However, according to the melatonin ability to cross lipid bilayers, nitroxides placed deep in the bilayer were able to(More)
The xylem-inhabiting bacterium Xylella fastidiosa (Xf) is the causal agent of Pierce's disease (PD) in vineyards and citrus variegated chlorosis (CVC) in orange trees. Both of these economically-devastating diseases are caused by distinct strains of this complex group of microorganisms, which has motivated researchers to conduct extensive genomic sequencing(More)
Cancer cachexia induces loss of fat mass that accounts for a large part of the dramatic weight loss observed both in humans and in animal models; however, the literature does not provide consistent information regarding the set point of weight loss and how the different visceral adipose tissue depots contribute to this symptom. To evaluate that, 8-week-old(More)
Endopeptidase 24.15 (EC; ep24.15), neurolysin (EC; ep24.16), and angiotensin-converting enzyme (EC; ACE) are metallopeptidases involved in neuropeptide metabolism in vertebrates. Using catalytically inactive forms of ep24.15 and ep24.16, we have identified new peptide substrates for these enzymes. The enzymatic activity of ep24.15 and ep24.16 was(More)
Homology modeling of the angiotensin II AT(1A) receptor based on rhodopsin's crystal structure has assigned the 92-100 (YRWPFGNHL) sequence of the receptor to its first extracellular loop. Solution and membrane-bound conformational properties of a peptide containing this sequence (EL1) were examined by CD, fluorescence, and (1)H-NMR. CD spectra in aqueous(More)
Sea anemones produce a wide variety of biologically active compounds, such as the proteinaceous neurotoxins and cytolysins. Herein we report a new peptide, purified to homogeneity from the neurotoxic fraction of B. caissarum venom, by using gel filtration followed by rp-HPLC, naming it as BcIV. BcIV is a 41 amino acid peptide (molecular mass of 4669 amu)(More)
Sticholysins I and II (St I and St II) are water-soluble toxins produced by the sea anemone Stichodactyla helianthus. St I and St II bind to biological and model membranes containing sphingomyelin (SM), forming oligomeric pores that lead to leakage of internal contents. Here we describe functional and structural studies of the toxins aiming at the(More)
The low spin states of microperoxidases (MP)-8, -9 and -9 N-acetylated (N-Ac) were characterized using UV-visible, circular dichroism, and electron paramagnetic resonance spectroscopies over the 6.0-12.0 pH range. The first MP-8 alkaline transition (pK(a)=8.53) produced hemepeptide aggregates in the low spin state in which a water molecule was replaced by(More)