Application of proteomic to investigate the different degrees of meat tenderness in Nellore breed.

This study describes the association between meat tenderness and abundance of soluble muscle proteins in Nellore bulls (Bos indicus) using a proteomic approach. We evaluated shear force (SF) of Longissimus thoracis muscle 24 h after slaughter and selected three experimental groups of animals with moderately tender (TE; SF = 3.9 ± 0.7 kg), moderately tough (TO; SF = 5.6 ± 0.7 kg) and very tough meat (TO+; SF = 7.9 ± 1.4 kg). Proteome was investigated by two-dimensional electrophoresis (2D-PAGE) in combination with electrospray ionization-tandem mass spectrometry (ESI-MS/MS). The metabolic proteins triosephosphate isomerase (TPI1) and phosphoglucomutase 1 (PGM1), the structural protein profilin 1 (PFN1), and cytosol aminopeptidase (LAP3) were up-regulated (P < 0.05) in the TE meat group when compared to the TO and TO+ groups. Actin structural proteins (ACTA1, ACTB, and ACTG1), the oxidative stress protein peroxiredoxin (PRDX6, PRDX2, PRDX1, and PARK7), heat shock protein isoforms, and co-chaperones (CDC37 and STIP1) were up-regulated (P < 0.05) in the TO and TO+ meat groups. In addition, we also identified proteins PFN1, LAP3, PRDX1, PRDX2, HSPD1, and ARHGDIA to be associated with beef tenderness. The results reported herein demonstrated that meat tenderness in Nellore cattle depends on the modulation and expression of a set of proteins involved in different biological pathways. SIGNIFICANCE: The manuscript entitled "Application of proteomic to investigate the different degrees of meat tenderness in Nellore breed" describes a classical proteomics work using two-dimensional gel electrophoresis (2D-PAGE), followed by mass spectrometry coupled to electrospray ionization ion trap (ESI-MS/MS) in order to understand the biochemical engineering involved in the process of meat tenderness. We evaluated shear force (SF) of Longissimus thoracis muscle samples of Nellore cattle (n = 90) and select three experimental groups of animals with moderately tender (TE; SF = 3.9 ± 0.7), moderately tough (TO; SF = 5.6 ± 0.7) and very tough meat (TO+; SF = 7.9 ± 1.4). The proteomic approach allowed observing that meat tenderness is influenced by structural proteins (ACTA1, ACTG1, ACTB, MYL1 and PFN1), co-chaperones (CDC37 and STIP1), heat shock proteins (HSP90AA1, HSP90AB1, HSPD1, HSPA1L, HSPA1A and HSPB1), regulatory protein (ARHGDIA), metabolic proteins (TPI1 and PGM1) and oxidative stress proteins (PRDX1, PRDX2, PRDX6, PARK7). Our results suggest that meat tenderness in Nellore depends on the modulation and expression of a set of proteins involved in different biological pathways.

Proteomic investigation of liver from beef cattle (Bos indicus) divergently ranked on residual feed intake.

Proteomics studies can be used to identify proteins that affect feed efficiency traits, related to cost and profitability of meat production. We used a proteomic approach based on two-dimensional electrophoresis (2D-PAGE) in combination with mass spectrometry (ESI-MS) to study liver samples of Nellore bulls divergently ranked according to residual feed intake (RFI). The study showed that 71 protein spots were expressed differentially (P < 0.05) among RFI groups and 47 were identified by ESI-MS. In RFI, efficient animals (low RFI) eat less than predictions, based on their weights and growth rate, while inefficient animals (high RFI) that eat more than predicted. Data from 18 animals (9 high vs. 9 low RFI) aged 24-26 months in feedlot finishing were used. Immediately after slaughter, liver samples were collected and protein extracts were separated. The gels of RFI groups were scanned and the images analyzed, whereby we found 279 and 215 liver protein spots in high and low RFI bulls, respectively. The proteins identified were related to the following biological functions: (I) oxygen transport and blood flow; (II) mitochondrial function and energy metabolism; (III) amino acid metabolism, ion transport, and cell survival. The study suggests hemoglobin subunit beta and heat shock protein 71 kDa and as molecular markers to study FE in Nellore cattle. Moreover, proteins such as 3-ketoacyl-CoA thiolase and glutamate dehydrogenase 1 were found in liver from high and low RFI animals, respectively. Such protein expression could be associated with changes in the oxidative capacity of RFI phenotypes.

Metalloproteomics Approach to Analyze Mercury in Breast Milk and Hair Samples of Lactating Women in Communities of the Amazon Basin, Brazil.

Mercury is a potentially toxic element that is present in the environment of the Brazilian Amazon and is responsible for adverse health effects in humans. This study sought to assess possible protein biomarkers of mercury exposure in breast milk samples from lactating women in the Madeira and Negro Rivers in the Brazilian Amazon. The mercury content of hair samples of lactating women was determined, and the proteome of breast milk samples was obtained using two-dimensional electrophoresis after protein precipitation with acetone. Mercury measurements of protein spots obtained via protein fractionation were performed by graphite furnace atomic absorption spectrometry (GFAAS), and it was observed that mercury is linked to proteins with molecular masses in the range of 14-26 kDa. The total mercury concentration was also determined by GFAAS in unprocessed milk, lyophilized milk, and protein pellets, with the purpose of determining the mercury mass balance in relation to the concentration of this element in milk and pellets. Approximately 85 to 97% of mercury present in the lyophilized milk from samples of lactating women of the Madeira River is bound in the protein fraction. From lactating women of the Negro River, approximately 49% of the total mercury is bound in the protein fraction, and a difference of 51% is bound in the lipid fraction.

Mercury fractionation in dourada (Brachyplatystoma rousseauxii) of the Madeira River in Brazil using metalloproteomic strategies.

This paper presents the results of mercury fractionation in muscle samples of dourada (Brachyplatystoma rousseauxii) from the JIRAU Hydroelectric Power Plant in the Madeira River Basin in the Amazon region of Brazil. The proteome of the dourada muscle was separated by two-dimensional polyacrylamide gel electrophoresis (2D PAGE). The mercury present in the protein spots was determined by graphite furnace atomic absorption spectrometry (GFAAS) after acid mineralisation in an ultrasound bath. The protein spots in which the presence of mercury was detected were characterised by electrospray ionisation tandem mass spectrometry (ESI-MS/MS) after tryptic digestion. The GFAAS determinations indicated that 65% of the mercury was linked to the protein fraction with a molar mass (Mm) of less than 90 kDa. The mercury concentrations in the seven spots in which this protein fraction was present were in the range of 11.40-35.10 µg kg(-1). Based on the mercury concentrations, it was possible to estimate that the protein spots contained approximately 1-3 mercury atoms per protein molecule. The ESI-MS/MS analysis allowed characterisation of the seven protein spots as the following proteins: protein NLRC5 (molar mass=18.10, pI=6.30); 39S ribosomal protein L36 mitochondrial (molar mass=15.40, pI=8.23); N-alpha-acetyltransferase 20 (Mm=15.95, pI=8.80); Mth938 domain-containing protein (Mm=15.01, pI=9.60); ubiquitin-40S ribosomal protein S27a (Mm=9.80, pI=7.60); parvalbumin alpha (Mm=12.40, pI=3.80) and parvalbumin beta (Mm=13.10, pI=3.45).

Minimally invasive computer-assisted stereotactic fenestration of an aqueductal cyst: case report.

INTRODUCTION: Current advances in frame modeling and computer software allow stereotactic procedures to be performed with great accuracy and minimal risk of neural tissue or vascular injury. CASE REPORT: In this report we associate a previously described minimally invasive stereotactic technique with state-of-the-art 3D computer guidance technology to successfully treat a 55-year-old patient with an arachnoidal cyst obstructing the aqueduct of Sylvius. We provide detailed technical information and discuss how this technique deals with previous limitations for stereotactic manipulation of the aqueductal region. We further discuss current advances in neuroendoscopy for treating obstructive hydrocephalus and make comparisons with our proposed technique. CONCLUSION: We advocate that this technique is not only capable of treating this pathology but it also has the advantages to enable reestablishment of physiological CSF flow thus preventing future brainstem compression by cyst enlargement.

Preconcentration and determination of Cu(II) in a fresh water sample using modified silica gel as a solid-phase extraction adsorbent.

A method was developed to attach 4-amino-2-mercaptopyrimidine (AMP) onto silica gel surface and to determine trace metals. The surface functionalization reaction was performed with a silylant agent, chloropropyltrimethoxysilane (Si-CPTS), and the product, Si-AMP, was characterized by FT-IR and elemental analysis to evaluate the surface modification. The functionalized silica was applied in the sorption of Cu(II) ions from an aqueous medium. The series of adsorption isotherms were adjusted to a modified Langmuir equation and the maximum number of moles of adsorbed copper was 0.447 mmol g(-1). The modified material was placed in a preconcentration system, where it reached an approximately 20-fold enrichment factor using 5mg of Si-AMP. The proposed method was applied in the preconcentration and determination of Cu(II) in a fresh water sample from the Paraná river and was validated through a comparative analysis of a standard reference material (1643e).

Tangential-flow ultrafiltration: a versatile methodology for determination of complexation parameters in refractory organic matter from Brazilian water and soil samples.

In this work the copper(II) complexation parameters of aquatic organic matter, aquatic and soil humic substances from Brazilian were determined using a new versatile approach based on a single-stage tangential-flow ultrafiltration (TF-UF) technique (cut-off 1 kDa) and sensitive atomic spectrometry methods. The results regarding the copper(II) complexation capacity and conditional stability constants obtained for humic materials were compared with those obtained using direct potentiometry with a copper-ion-selective electrode. The analytical procedure based on ultrafiltration is a good alternative to determine the complexation parameters in natural organic material from aquatic and soil systems. This approach presents additional advantages such as better sensibility, applicability for multi-element capability, and its possible to be used under natural conditions when compared with the traditional ion-selective electrode.

Determination of Cu, Ni, and Zn in fuel ethanol by FAAS after enrichment in column packed with 2-aminothiazole-modified silica gel.

This work describes the synthesis and characterization of 2-aminothiazole-modified silica gel (SiAT), as well as its application for preconcentration (in batch and column technique) of Cu(II), Ni(II) and Zn(II) in ethanol medium. The adsorption capacities of SiAT determined for each metal ion were (mmol g(-1)): Cu(II)=1.20, Ni(II)=1.10 and Zn(II)=0.90. In addition, results obtained in flow experiments, showed a recovery of ca. 100% of the metal ions adsorbed in a column packed with 500 mg of SiAT. The eluent was 2.0 mol L(-1) HCl. The sorption-desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in fuel ethanol using flame AAS for their quantification.