1,721,067 research outputs found
Free Energy Changes and Components Implicit in the MWC Allosteric Model for the Cooperative Oxygen Binding of Hemoglobin
Full text linkHill's plots of oxygen binding isotherms reveal the presence of a transition between two different oxygen affinities at the beginning and end of the isotherm. They correspond to the two conformations anticipated by the MWC model, namely, the T and R conformations at the beginning and end of oxygen binding, when the lower affinity of the T form develops into the higher affinity of the R form. The difference between the binding Gibbs free energy changes of the two affinities (ΔGL) is the free energy of binding cooperativity. Notably, ΔGL is positive in favor of the T form, which moves to a higher energy level upon oxygen release. Osmotic stress reveals a higher volume/surface ratio of deoxyhemoglobin, with a positive ΔGW also in favor of the T form. An increasing protein concentration shifts the isotherms to the right, indicating the formation of intermediate polymeric forms. The enthalpy of the intermediates shows a strong absorption of heat at the third oxygenation step because of polymer formation with quinary, and higher-order, structures. The disassembly of intermediate polymers releases energy with a negative ΔG that compensates and allows the positive values of ΔGL. High-energy polymers are the barrier preventing the relaxation of the T and R conformations into one another. The MWC allosteric model is the best justification of oxygen binding cooperativity
CD38 in bovine lung: a multicatalytic NADase
No full textWe report the kinetics and molecular properties of CD38 purified from bovine lung microsomal membranes after its solubilization with Triton X-100. The enzyme was found to be a novel member of a multicatalytic NAD+ - glycohydrolase (NADase, EC 3.2.2.6). It was able to utilize NAD+ in different ways, producing nicotinamide (Nam) and either adenosine diphosphoribose (ADPR, NADase activity) or cyclic ADPR (cADPR, cyclase activity); it also catalyzed the hydrolysis of cADPR to ADPR (cADPR, hydrolase activity). In addition, the enzyme catalyzed the pyridine base exchange reaction with conversion of NAD+ into NAD analogues. These data are evidence that CD38 is involved in the regulation of both NAD+ and calcium mobilizing agents, the concentration resulting in an essential enzyme that plays a key role in cellular energy and signal-transduction systems
11th workshop on PharmacoBioMetallics (BIOMET11)
No full text11th workshop on PharmacoBioMetallics (BIOMET11).
San Benedetto del Tronto (AP), 28-30 ottobre 2011.
Organizzato da: Università degli Studi di Camerino, Scuola di Scienze e Tecnologie, Sezione Chimica, per il Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici (CIRCMSB)
Studies on the antimicrobial activity of Silver Nanoparticles as additive for several kind of materials
No full textStudies on the antimicrobial activity of Silver Nanoparticles as additive for several kind of materials
Rossana, Galassi;a Anna Teresa, Ramadori;a § Alfredo, Burini;a Daniela, Micozzi;b Stefania, Pucciarelli.b
a Scuola di Scienze e Tecnologie, Divisione di Chimica, Università di Camerino, Via Sant’Agostino, 1, Camerino, I-62032, Italy.
b Scuola di Bioscienze e Medicina Veterinaria, Polo di Bioscienze, Università di Camerino, Via Gentile III da Varano, Camerino, I-62032, Italy.
§ fellow granted by project T.R.A.S.P.A.R.E.N.T.E. DGR 1464 del 7/11/2011, Regione Marche.
Silver nanoparticles (AgNPs) have attracted extensive research interest due to their attractive optical, electronic properties and excellent antimicrobial activities. AgNPs exhibit strong cytotoxicity towards a broad range of microorganisms and are widely used as an antibacterial agents.1 The advantage of AgNPs compared to bulk metal or salts is the slow and regulated release of silver from nanoparticles, thereby causing long lasting protection against bacteria. The antimicrobial activity of AgNPs is comparatively better than most prominent antibiotics used worldwide.2 Numerous methods have been developed for the preparation of AgNPs. The most common method is the chemical reduction of silver salt by a reducing agent in the presence of a stabilizing agent. In this work AgNPs have been prepared by reducing silver cations with NaBH4 and using as stabilizer sodium citrate, PVP (polivinylpirrolidone) or polysaccharides. AgNPs so obtained were characterized as average 10 nm particles by DLS and UV-vis spectroscopy. This work has the aim to verify the biocide action of silver nanoparticles mainly in plasters but also in other substrates occurring in a civil environment to reduce exposure to risk of infection by people with weak immune system. The study was focused to develop a method of study for each kind of material both in the AgNPs dispersion’s method and on the antimicrobial activity of the resulting substrate treated with AgNps. The antimicrobial activity has been led on Escherichia coli cells cultured in Luria Broth.3 The minimum concentration needed to have effects has been determined in each case. Moreover a comparative study of the inhibitory effect of AgNPs and silver salts such as AgNO3 and AgCF3SO3 on the regards of DHFR (DeHydroFolateReductase) from E. Coli has been performed.
1) Xihui Zhao; Yanzhi Xia; Qun Li; Xiaomei Ma Fengyu, Quan Cunzhen Geng, Zhenyu Han. Colloids and Surfaces A: Physicochem. Eng. Aspects 444, 2014, 180-188. doi.org/10.1016/j.colsurfa.2013.12.008
2) R. Roy, M. R. Hoover, A. S. Bhalla, T. Slawecki, S. Dey, W. Cao, J. Li, S. Bhaskar. Material Research Innovation, Volume 11, Issue 1 ,2007, 3-18. DOI 10.1179/143307507X196167.
3) Ivan Sondi and Branka Salopek-Sondi. Journal of Colloid and Interface Science 2004, 275, 177-182. doi:10.1016/j.jcis.2004.02.01
Enzymology of Pyrimidine Metabolism and Neurodegeneration
No full textIt is well known that disorders of pyrimidine pathways may lead to neurological, hematological, immunological diseases, renal impairments, and association with malignancies. Nucleotides homeostasis depends on the three portion of pyrimidine metabolism: de novo synthesis, catabolism and recycling of these metabolites. Cytidine and uridine, in addition to be used as substrates for pyrimidine nucleotide salvaging, also act as the precursors of cytidine triphosphate used in the biosynthetic pathway of both brain phosphatidylcholine and phosphatidylethanolamine via the Kennedy cycle. The synthesis in brain of phosphatidylcholine and other membrane phosphatides can utilize, in addition to glucose, three compounds present in the blood stream: choline, uridine, and a polyunsaturated fatty acis like docosahexaenoic acid. Some authors, using rat models, found that oral administration of two phospholipid precursors such as uridine and omega-3 fatty acids, along with choline from the diet, can increase the amount of synaptic membrane generated by surviving striatal neurons in rat models with induced Parkinson's disease. Other authors found that in hypertensive rat fed with uridine and choline, cognitive deficit resulted improved. Uridine has also been recently considered as a neuroactive molecule, because of its involvement in important neurological functions by improving memory, sleep disorders, anti-epileptic effects, as well as neuronal plasticity. Cytidine and uridine are uptaken by the brain via specific receptors and successively salvaged to the corresponding nucleotides. The present review is devoted to the enzymology of pyrimidine pathways whose importance has attracted the attention of several researchers investigating on the mechanisms underlying the physiopathology of brain
A preliminary study on milk kefir proteomic characterization.
No full textKefir is a South Caucasian drink, belonging to traditional fermented milk, it is made by inoculating cow, goat, or sheep milk with kefir “grains” which is a starter made up of proteins, lipids, bacteria and yeasts kept together by a liposoluble polysaccharide called "Kefiran".
From a nutritional point of view, the proteins in milk kefir are partially digested so that they can be easily used by the organism, it is a font of essential amino acids, calcium and magnesium, important minerals for the maintenance of a healthy nervous system, phosphorus and vitamins. Milk kefir is also considered a probiotic drink thanks to the large numbers of microorganisms that are present in this beverage, it is suitable for lactose-intolerant individuals since the “grains” shows a -galactosidase activity. A very recent study, performed in high-fat diet mice, reported that kefir consumption modulates gut microbiota and mycobiota and prevents obesity and fatty liver disease by promoting fatty acid oxidation [1]. However, until now, there is a gap in literature on the proteomic composition of this fermented drink. Therefore, the objective of this study was a proteomic analysis of kefir milk (derived from bovine milk) by two-dimensional electrophoresis (2-DE). Before to be analyzed, kefir milk was centrifuged (13000g for 20 min) and then filtered with 0.22 filter in order to remove bacteria. The total protein present in the filtered kefir were concentrated by precipitation with 90% ammonium sulphate. The precipitated proteins were resuspended in 50mM tris/HCl pH 7.5 and before 2-DE were treated with 2D-Clean-Up (GE Healthcare). 0,5 mg of total proteins were resuspended in a rehydratation buffer containing urea and detergents and subjected to isoelectric focusing on an immobilized pH gradient 3-10 (Immobiline DryStrip gel, 18cm, GE Healthcare). The second dimension consisted of a 15% SDS-PAGE. After electrophoresis, the proteins were stained by Coomassie blue. The gel was analyzed by the software PDquest (Bio-Rad) for spot quantitation, determination of isoelectric point and molecular weight. As a result, were found two broad protein regions, one in the pH range of 3.4-6.2 and Mr of about 31.0 kDa, another one in the pH range of 3.4-5.3 and Mr of about 21.0 kDa which could derive from bovine milk casein and -lactoglobulin, respectively. Interestingly, there are several low molecular weight peptides, which may derive from the fermentative processes. The presence of low molecular weight peptides is one of the characteristics that determines the digestibility of kefir milk with respect to whole bovine milk. These low molecular weight proteins may be the bioactive peptides, defined as specific protein fragments that have a positive impact on body functions and conditions and may ultimately influence health [2]. Bioactivities described for milk-derived peptides includes opiate, immunomodulatory, antimicrobial, antioxidative, antithrombotic, anticancer, mineral carrying and growth-promoting properties. These milk-derived peptides are mainly obtained from milk casein, but some classes of peptides are also derived from whey proteins and may show one or more synergic activities [3].
The data obtained in this preliminary study are very encouraging and, up to now, there aren’t data on the kefir proteomic characterization in the literature. The spot proteins separated by 2-DE will be extracted from the gel and will be identified by mass spectrometry. The results that will be obtained from this study will clarify the protein composition of kefir milk and also identify and characterize the peptides (of which this matrix is particularly rich) that could have an important nutraceutical function and hence a positive impact on human health
A comparison of the carcass and meat quality of Martina Franca donkey foals aged 8 or 12 months
No full textThe effects of slaughter age (8 vs 12 months) were investigated on meat and carcass quality obtained from
Martina Franca donkey foals. Sixteen male foals were used, eight were slaughtered at 8 months of age with a
mean (±s.e.) final body weight of 101 ± 18 kg and the remaining 8 foals slaughtered at 12 months of age
with a mean final body weight of 122 ± 13 kg.
Carcass weight and dressing percentage were higher (P b 0.05) in older foals. Shear force value was lower
(P b 0.05) in donkeys slaughtered at 8 months of age (54.03 N) compared to the same muscle Longissimus
Thoracis et Lumborum (LTL) collected in older animals (62.66 N). Muscle glycogen content was higher
(P b 0.05) in foals slaughtered at 12 months of age. Donkey foal meat showed an interesting content of essential
amino acids and a notable percentage of unsaturated fatty acids in both groups of animals, giving a high nutritional
value to this alternative red meat
Preliminary Studies on the Synthesis and Antimicrobial activity of TiO2/Ag/Au nanoparticles on materials for sanitation of indoor Ambient Assisted Living environments.
No full textPreliminary Studies on the Synthesis and Antimicrobial activity of TiO2/Ag/Au nanoparticles on materials for sanitation of indoor Ambient Assisted Living environments.
Ramadori A. T. a,b Galassi R.,a Micozzi, D.,c Pucciarelli, S. c
a School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino; e-mail: [email protected]
b Fellow from T.R.A.S.P.A.R.E.N:T.E project
c School of Biology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino;
Infectious diseases contracted in the home environment are still a significant problem in the western world due to the excessive use of antibiotics, the occurrence of bacterial resistance and not always correct behavior of the population; prevention and personal hygiene are able to dramatically reduce the risk of transmission, but in some circumstances, for example in the case of older people not fully self-sufficient, long-term care in hospitals and residential health and social environments, which are overcrowded and poorly ventilated, normal personal and domestic hygiene measures may be insufficient.1 Hence, in the development of new technology for the improvement of the sanitation of environments and objects, the use of nanoparticle (NP) systems2 based on Au, Ag and TiO2 NPs was taken into consideration as additives in plasters, resins for water-based paints and varnishes. TiO2 has been purchased, while different Au and Ag NPs syntheses have been perfomed.3 The NPs have been characterized by spectroscopic methods such as UV-vis or IR spectroscopy. Different formulations and concentrations of NPs have been attempted. The obtained samples were tested to evaluate their antimicrobial activity on pathogenic coltures.
References:
1) a) Bruce, N.; Perez-Padilla, R.; Albalak, R. Bull.World Health Org. 2000, 78, 1078-1092. b) Gandara, A.; Mota, L. C.; Gibbs S. G. Environ. Health Perspective 2006, 114, 1859-1864.
2) Ashavani, K.; Praveen, K. V.; Pulickel, M. A.; George, J. Nature Materials 2008, doi:10.1038/nmat2099.
3) a) Wojtysiak, S.; Kudelski, A. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2012, 410, 45-51. b) Rohiman, A., Anshori, I., Surawijaya, A., Idris, I. AIP Conf. Proc. 2011, 1415, 39-42. c) Cubillana-Aguilera, L.M.; Franco-Romano, M.; Gil, M.L.A.; Naranjo-Rodríguez, I.; Hidalgo-Hidalgo de Cisneros, J. L.; Palacios-Santander, J.M. Ultrasonics Sonochemistry, 2011, 18, 789-794
Donkey's Milk: a set of nutritional properties
No full textDonkey's milk has been proposed as a good and safer alternative to other types of milk for some consumer categories, among all infants affected by cow's milk protein allergy (CMPA), when it is not possible breast feeding. The peculiarity of donkey's milk is to be very similar to human milk especially as regards to its lactose content, protein and mineral composition
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