Determinação da estrutura e estudo da função da metalotioneína de Synechococcus com ferramentas da bioinformática.

Este trabalho abordou a análise estrutural das MTs a fim de se modelar esta proteína e com isso compreender melhor o funcionamento da mesma. O conhecimento da cianobactéria e uma completa análise da MT poderia ser muito útil em um estudo de utilização desta na técnica da biorremediação para remover metais pesados do solo e da água decorrentes das praticas agrícolas atuais.bitstream/CNPTIA/9902/1/comuntec43.pdfAcesso em: 30 maio 2008

Alterações histológicas dos rins e expressão das metalotioneínas e das proteínas de choque térmico em ratos Wistar após exposição ao fungicida tirame

The histological alterations and the expression of metallothionein (MTs) and heat shock protein (Hsp70) in the kidney of Wistar rats after thiram fungicide exposure were evaluated. Animals were distributed into three groups: standard diet group, standard diet + corn oil group and thiram group. Significant differences were found (P<0,05) in the evolution of body weight between rats in the thiram group and those in the control and corn oil groups, and no histological lesions were evident in the animals' kidneys. Differences were found among animals in the group exposed to thiram and the control and oil groups regarding histomorphometric characteristics of the renal corpuscle - except for the proportion in the area of Bowman's capsule: glomerulus area - and regarding the height of the epitelium in the distal tubules. In rats exposed to thiram, a positive moderate to strong immunoexpression was observed for MTs, in the cortical convulated tubules decreasing the cortex towards the medulla, and a strong immunoexpression for Hsp70 in the cortex and medulla areas, in the glomerulus and convulated tubules. The results suggest that thiram may have chronic toxicity in mammals affecting their growth, and that the expression of MTs and Hsp70, a probable cellular adaptive response to the oxidative stress caused by thiram, may be used as a biomarker of exposure to this chemical.info:eu-repo/semantics/publishedVersio

Kidney histological alterations and metallothionein and heat shock protein expression in Wistar rats after fungicide thiram exposure

The histological alterations and the expression of metallothionein (MTs) and heat shock protein (Hsp70) in the kidney of Wistar rats after thiram fungicide exposure were evaluated. Animals were distributed into three groups: standard diet group, standard diet + corn oil group and thiram group. Significant differences were found (P<0,05) in the evolution of body weight between rats in the thiram group and those in the control and corn oil groups, and no histological lesions were evident in the animals’ kidneys. Differences were found among animals in the group exposed to thiram and the control and oil groups regarding histomorphometric characteristics of the renal corpuscle – except for the proportion in the area of Bowman’s capsule: glomerulus area – and regarding the height of the epitelium in the distal tubules. In rats exposed to thiram, a positive moderate to strong immunoexpression was observed for MTs, in the cortical convulated tubules decreasing the cortex towards the medulla, and a strong immunoexpression for Hsp70 in the cortex and medulla areas, in the glomerulus and convulated tubules. The results suggest that thiram may have chronic toxicity in mammals affecting their growth, and that the expression of MTs and Hsp70, a probable cellular adaptive response to the oxidative stress caused by thiram, may be used as a biomarker of exposure to this chemical. Keywords: rat, kidney, thiram, histology, metallothioneins, heat shock proteins (Hsp70

Mercury content of some canned seafood collected from Nigerian retail markets

Twenty samples of canned seafood consisting of tuna, mackerel, sardines, prawn and shrimp were collected from retail operations in Victoria Island, Lagos, Nigeria. Mercury content in these canned seafood were determined after digestion by the Association of Official Analytical Chemists methods. The mercury contents for all the canned seafood products have concentrations well below the permissible EU levels for this toxic metal. Their contribution to the body burden can therefore be considered negligible and the canned seafood products seem to be safe for human consumption

Heavy metals and sensory evaluation of canned tuna fish

In this study, two heavy metals in canned tuna fish were determined after digestion by the AOAC methods. Mercury and Cadmium levels in canned tuna fish were determined by flame atomic absorption photometry. The results of this study indicate that canned tuna fish imported into the country have concentrations well below the petmissible FAO/WHO levels for these toxic metals. Their contribution to the body burden can therefore be considered negligible and the fish seem to be safe for human consumption. For the sensory evaluation, tuna flakes in vegetable oil (Starkist) from Ghana and light meat tuna chunks in sunflower oil (John West) from Thailand were the most preferred while tuna flakes in brine (John West) from Thailand is the least preferred

The Iron-Type Nitrile Hydratase Activator Protein Is A GTPase

The Fe-type nitrile hydratase activator protein from Rhodococcus equi TG328-2 (ReNHase TG328-2) was successfully expressed and purified. Sequence analysis and homology modeling suggest that it is a G3E P-loop guanosine triphosphatase (GTPase) within the COG0523 subfamily. Kinetic studies revealed that the Fe-type activator protein is capable of hydrolyzing GTP to GDP with a kcat value of 1.2 × 10−3 s−1 and a Km value of 40 μM in the presence of 5 mM MgCl2 in 50 mM 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid at a pH of 8.0. The addition of divalent metal ions, such as Co(II), which binds to the ReNHase TG328-2 activator protein with a Kd of 2.9 μM, accelerated the rate of GTP hydrolysis, suggesting that GTP hydrolysis is potentially connected to the proposed metal chaperone function of the ReNHase TG328-2 activator protein. Circular dichroism data reveal a significant conformational change upon the addition of GTP, which may be linked to the interconnectivity of the cofactor binding sites, resulting in an activator protein that can be recognized and can bind to the NHase α-subunit. A combination of these data establishes, for the first time, that the ReNHase TG328-2 activator protein falls into the COG0523 subfamily of G3E P-loop GTPases, many of which play a role in metal homeostasis processes

Coordinated regulation of ceruloplasmin and metallothionein mRNA by interleukin-1 and copper in HepG2 cells

AbstractDuring the acute phase response, cytokines induce hepatic metallothionein and ceruloplasmin synthesis and the uptake of metals. We have investigated how copper and cytokines may interact in controlling ceruloplasmin (CP) and metallothionein mRNA in liver cells. We found that IL-1α, IL-1β and IL-6 increased both metallothionein-1 (MT-1) and metallothionein-2 (MT-2) mRNA in HepG2 cells. The time and pattern of induction was different, both IL-1α and IL-1β inducing two peaks of MT-1 and MT-2, with that of MT-2 being much larger. IL-6 induced only low levels of both MT-1 and MT-2 mRNA. CP mRNA was also increased after 16 h by IL-1β, whereas IL-1α induced two CP peaks at 8 and 20 h, while IL-6 had little effect. Copper administration gave rise to substantially increased MT-1 mRNA, a slightly lower increase in MT-2 and also a significant increase in CP mRNA with similar kinetics. These parallel increases in MT and CP mRNA suggest that the coordinated expression of these proteins may be important for their synthesis during the acute phase response

Adsorption of Gold from Aqueous Systems Using Microbial Thermophilic Proteins

A precious metal such as gold can be obtained from mining. Metals in low concentrations at geothermal sites or in industrial waste are difficult to gain using the conventional mining process. Alternative approaches for recovering metals from dilute solutions have been developed, such as biosorption, i.e. adsorption using microorganisms or their derivatives. In this study, gold in an aqueous system was recovered via biosorption using proteins produced from an isolated thermophilic bacterial strain. Modified Thermus enhanced medium was used as the medium to improve protein production from the thermophilic bacterial strain. The microbial proteins showed effective conditions for Au3+ ion adsorption. The optimum adsorption conditions for Au ions occurred at pH 1 with an adsorption capacity of 482.0 mg/g protein. The metal ion adsorption capacity increased with increasing temperature. The adsorption isotherm was conducted at room temperature, because the Au ions could be well fitted by the Freundlich isotherm equation with qmax at 527.229 mg/g protein

Studi Kandungan Logam Berat Pb, Cu, Cd, Cr Pada Kerang Simping (Amusium Pleuronectes), Air Dan Sedimen Di Perairan Wedung, Demak Serta Analisis Maximum Tolerable Intake Pada Manusia

Wedung, Demak which have large potential of asian moon scallop (Amusium pleuronectes). This potential has leaded the increasing activities of fishing, industrial, and dense residential in Wedung. Those activities were thought to be one of the sources of heavy metals (Pb, Cu, Cd, Cr) accumulated in the simping. This study was aimed to determine the concentration of Pb, Cu, Cd, Cr in the A. pleuronectes, in the water and the sediment. Moreover, this study was also aimed to investigate the maximum weekly consumption A. pleuronectes which contained Pb, Cu, Cd, and Cr in Wedung waters area, Demak. The study was conducted in October-November 2011. The method used in this study was a study case method, while the purposive sampling method was used to determine the sampling locations. Sampling was conducted once every two week, with three repetitions. AAS (Atomic Absorbtion spectrophotometry), were used to analyze the heavy metal concentration, while the consumption of security analysis was used to analyze the MTI (Maximum Tolerable Intake). The range of the analysis results of Pb concentration in the scallop's shells were 33,1362 – 35,0762 ppm, and 11,1272 – 13,0852 ppm in the sediments, while the concentration in the soft tissues and water, were not detected. The Cu concentration in the soft tissue were ranged from 8,9849 – 9,4659 ppm, where in the scallop's shells were 11,9836 – 12,2358 ppm, water were 0,07 – 0,14 ppm, and in the sediments were 13,0624 – 17,6040 ppm. The Cd concentration in soft tissue were ranged from 5,9212 – 8,0136 ppm, scallop's shell were 2,6195 – 5,0125 ppm, and water were 0,01 ppm at 2nd and 3rd samplings, while at the first sampling was not detected, whereas in the sediments the concentration ranged from 0,4694 – 0,7257 ppm. Cr concentration in the soft tissue were only detected in the third sampling with 0,7285 ppm, while in the scallop's shells ranged from 1,9694 – 2,6924 ppm, and in the sediments were 0,9693 – 1,6933 ppm, while its concentration in water was not detected. Maximum weekly intake of scallop in Wedung water which are safe for consumption were 22,64 kg for Cu; 0,06 kg for Cd; and 5,76 kg of Cr per week for people with average body weight 60 kg, while the Pb concentration not detected