Genome-wide analysis of metallothionein gene family in maize to reveal its role in development and stress resistance to heavy metal

BACKGROUND: Maize (Zea mays L.) is a widely cultivated cereal and has been used as an optimum heavy metal phytoremediation crop. Metallothionein (MT) proteins are small, cysteine-rich, proteins that play important roles in plant growth and development, and the regulation of stress response to heavy metals. However, the MT genes for maize have not been fully analyzed so far. METHODS: The putative ZmMT genes were identified by HMMER. The heat map of ZmMT genes spatial expression analysis was generated by using R with the log2 (FPKM + 1). The expression profiles of ZmMT genes under three kinds of heavy metal stresses were quantified by using qRT-PCR. The metallothionein proteins was aligned using MAFFT and phylogenetic analysis were constructed by ClustalX 2.1. The protein theoretical molecular weight and pI, subcellular localization, TFs binding sites, were predicted using ProtParam, PSORT, PlantTFDB, respectively. RESULTS: A total of 9 ZmMT genes were identified in the whole genome of maize. The results showed that eight of the nine ZmMT proteins contained one highly conserved metallothio_2 domain, while ZmMT4 contained a Metallothio_PEC domain. All the ZmMT proteins could be classified into three major groups and located on five chromosomes. The ZmMT promoters contain a large number of hormone regulatory elements and hormone-related transcription factor binding sites. The ZmMT genes exhibited spatiotemporal specific expression patterns in 23 tissues of maize development stages and showed the different expression patterns in response to Cu, Cd, and Pb heavy metal stresses. CONCLUSIONS: We identified the 9 ZmMT genes, and explored their conserved motif, tissue expression patterns, evolutionary relationship. The expression profiles of ZmMT genes under three kinds of heavy metal stresses (Cu, Cd, Pb) were analyzed. In summary, the expression of ZmMTs have poteintial to be regulated by hormones. The specific expression of ZmMTs in different tissues of maize and the response to different heavy metal stresses are revealed that the role of MT in plant growth and development, and stress resistance to heavy metals.

Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance

Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd2+ and accumulated more Cd2+ ions when they were grown in the medium containing CdCl2. In addition, the heterologous expression of GST-OsMTI-1b conferred H2O2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses.

Nível de dependência e qualidade de vida da população idosa / Level of dependency and quality of life of elderly / Nivel de dependencia y calidad de vida de los ancianos

A qualidade de vida (QV) nos idosos é determinada em grande parte pelo seu estado funcional e condições de saúde. Com o objectivo de avaliar o nível de QV, os factores que a influenciam e identificar o grau de dependência dos idosos foi realizado um estudo observacional transversal do tipo exploratório-descritivo, englobando 93 idosos. Na recolha de dados utilizouse o índice de Barthel e MOS-SF 36. Na identificação dos níveis de dependência os resultados indicam-nos que 40,0% são independentes e 18,0% são dependentes mínimos, sendo 12,0% dependentes totais. No que diz respeito à QV 88,0% dos sujeitos refere uma pontuação inferior a 50,0%, em média reportam uma QV de 39±10,0%. Verificou-se que existe uma correlação positiva entre o grau de dependência e o índice de QV, sobretudo na componente física. Assim, importa promover um envelhecimento saudável procurando-se privilegiar a preservação da autonomia e capacidade funcional dos idosos.

The quality of life (QoL) in older adults is largely determined by their functional status and health conditions. With the purpose of investigate the QoL and the factors affecting it, and identify the degree of dependency of the elderly was carried out an observational cross-sectional exploratory and descriptive, involving 93 elderly. In collecting data we used the Barthel Index and MOS SF-36. In the identification of levels of dependency results indicate us that 40.0% are independent and 18.0% are dependents, minimum being 12.0% total-dependent. The results show us that, 88.0% of the subjects reported a score below 50.0% on average reported a QoL of 39±10.0%. Checking that are a positive correlation between the degree of dependence and the index of QoL, especially in the physical component. It is therefore important to promote healthy aging in an attempt to favor the preservation of autonomy and functional capacity of the elderly.

La calidad de vida (CV) en los adultos mayores es en gran parte determinado por su estado funcional y las condiciones de salud. Con el fin de evaluar el nivel de CV y los factores que influyen en ella y determinar el grado de dependencia de los ancianos se llevó a cabo un estudio observacional transversal, exploratorio y descriptivo, que involucró a 93 personas mayores. En la recopilación de datos se utilizó el Índice de Barthel y el MOS SF-36. En la identificación de los nivele de dependiencia los resultados nos indican que 40,0% son independientes, 18,0% são dependentes mínimos y 12,0% dependientes totales. En lo que respeicta a la CV, 88,0% de los sujetos reportaron una puntuación inferior a 50,0% en promedio reportó una CV de 39±10,0%. Tomando nota de que existe una correlación positiva entre el grado de dependencia y el índice de calidad de vida, especialmente en el componente físico. Por tanto, es importante promover un envejecimiento saludable, en un intento de favorecer la preservación de la autonomía y la capacidad funcional de los ancianos.

Role of complementary therapies in the understanding of primary healthcare professionals: a systematic review / Papel de prácticas complementarias en la comprensión de los profesionales de atención primaria: una revisión sistemática / Papel das práticas complementares na compreensão dos profissionais da Atenção Básica: uma revisão sistemática

Objective To identify the understanding of the healthcare professionals in relation to the role of complementary therapies in primary health care. Method Systematic review by way of the following information sources: PubMed, CINAHL, PeriEnf, AMED, EMBASE, Web of Science, Psicoinfo and Psicodoc, using the keyword Primary Health Care alone, and associated with the following keywords: Medicinal Plants, Herbal Medicine, Homeopathy, Traditional Chinese Medicine, Acupuncture, Anthroposophical Medicine. Results Twenty-two studies from 1986 to 2011 were included. We identified three styles of practice: conventional medicine, complementary therapies and integrative medicine. Positioning professional practices within these three styles may facilitate discussion of concepts of health care, enhancing the health care provided as a result. Conclusion The work process in primary care presents difficulties for conducting integrative and holistic health care, but this practice has been introduced over time by professionals who integrate conventional medicine and complementary therapies, concerned with the care and well-being of patients.
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Objetivo Identificar la comprensión de los profesionales sobre el papel de las prácticas complementarias en la atención primaria. Método Revisión sistemática. Fuentes de datos: PubMed, CINAHL, PeriEnf, AMED, EMBASE, Web of Science, Psicodoc y PysicoInfo. Descriptor Atención Primaria se asoció solo a los siguientes descriptores: plantas medicinales, fitoterapia, homeopatía, acupuntura, medicina tradicional china, medicina antroposófica. Resultados Se incluyeron 22 pesquisas entre 1986-2011. Tres estilos de práctica se identificaron: medicina convencional, medicina integrativa y Terapias Complementarias. Identificar la práctica profesional dentro de estos tres estilos puede facilitar la discusión de los conceptos de salud y la atención, mejorar la atención. Conclusión El proceso de trabajo en atención primaria presenta dificultades para realización de integración y atención integral, pero esta práctica se ha introducido con profesionales que integran medicina convencional y complementaria, ocupados con la atención y bienestar del paciente.


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Objetivo Identificar a compreensão dos profissionais de saúde quanto ao papel das práticas complementares na Atenção Básica. Método Revisão sistemática cujas fontes de informação foram: PubMed, CINAHL, PeriEnf, AMED, EMBASE, Web of Science, PysicoInfo e PsicoDoc, utilizando o descritor Atenção Básica associado, isoladamente, aos seguintes descritores: Plantas Medicinais, Fitoterapia, Homeopatia, Medicina Tradicional Chinesa, Acupuntura, Medicina Antroposófica. Resultados Incluíram-se 22 estudos entre 1986-2011. Identificaram-se três estilos de prática: medicina convencional, práticas integrativas e medicina integrativa. Posicionar a prática profissional dentro desses três estilos pode facilitar a discussão de concepções de saúde e cuidado, ampliando o cuidado. Conclusão O processo de trabalho na Atenção Básica apresenta dificuldades para a realização de cuidado integrativo e holístico, mas essa prática vem sendo introduzida com profissionais que integram medicina convencional e práticas complementares, preocupados com o cuidado e o bem-estar do paciente.

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Metallothionein: an overview on its metal homeostatic regulation in mammals / Metalotioneina: una visión general de su regulación homeostática de metales en mamíferos

Metallothionein (MT) is a ubiquitous protein with a low molecular weight of 6-7 kDa weight and it was first identified in the kidney cortex of equines as a cadmium (Cd)-binding protein responsible for the natural accumulation of Cd in the tissue. The mammalian MT contains 61 to 68 amino acid residues, in which 18 to 23 cysteine residues are present. The expression of MT starts by binding of metal transcription factor-1 (MTF-1) to the regulative region of MT gene called metal responsive elements (MREs). The induction of MT through the MREs region can be initiated by several metal ions such as zinc (Zn), copper (Cu) and Cd. However, Zn is the only heavy metal which can reversibly and directly activate the DNA-binding activity of MTF-1. In mammals four types of MT are expressed and they are termed metallothionein-1 (MT1), metallothionein-2 (MT2), metallothionein-3 (MT3), and metallothionein-4 (MT4). MT1 and MT2 are expressed in almost all tissues while MT3 and MT4 are tissue-specific. MT is a key compound involved in the intracellular handling of a variety of essential and nonessential post-transitional metal ions. In order to the heavy metal binding ability of MT, it is suggested to play roles both in the intracellular fixation of essential trace elements Zn and Cu, in controlling the concentrations, and in neutralizing the harmful influences of exposure to toxic elements...

Metalotioneina (MT) es una proteína, con bajo peso molecular de kDa 6-7 y que fue primero identificada en la corteza renal de equinos como cadmio (Cd)-proteína responsable por la acumulación natural de Cd en los tejidos. La MT en mamíferos contiene 61 a 68 residuos de aminoácidos, de los cuales están presentes 18 a 23 residuos de cisteína. La expresión de MT se inicia por la unión del factor-1 de transcripción de metal (MTF-1) a la región reguladora del gen de la MT llamado elementos metálicos responsable (MREs). La inducción de MT a través de la región MREs puede ser iniciada por varios iones metálicos tales como zinc (Zn), cobre (Cu) y Cd. Sin embargo, el Zn es el único metal pesado que puede revertir y activar directamente la unión ADN de MTF-1. En los mamíferos se expresan cuatro tipos de MT y ellos se denominan metalotioneína-1 (MT1), metalotioneína-2 (MT2), metalotioneína-3 (MT3), y metalotioneína-4 (MT4). MT1 y MT2 se expresan en casi todos los tejidos mientras que MT3 y MT4 son tejido-específico. La MT es un compuesto clave implicado en la manipulación intracelular de una variedad de iones metálicos esenciales y no esenciales post-transicionales. Con el fin de evaluar la capacidad de unión de metales pesados de MT, se sugiere que éste desempeña ambos roles tanto en la fijación intracelular de trazas de elementos de Zn y Cu como en el control de las concentraciones, y neutralizando las influencias perjudiciales a la exposición de elementos tóxicos...

Trypanosoma cruzi infection and/or administration of the nonsteroidal anti-inflammatory nimesulide increase the number of colonic crypts overexpressing metallothioneins in rat colon carcinogenesis

Trypanosoma cruzi infection and nonsteroidal anti-inflammatory drugs inhibit colorectal carcinogenesis by mechanisms not completely known and metallothionein proteins (MTs) may be involved in this process. Sixty-six male Wistar rats weighing 90 to 120 g were randomly divided into seven groups (GI to GVII). GI, GII and GIII animals were subcutaneously infected with 200,000 trypomastigote forms of the Y strain of T. cruzi. After 8 weeks, GI, GII, GIV, and GVI were injected with one weekly subcutaneous dose of 12 mg/kg dimethylhydrazine for 4 weeks. In sequence, GI, GIV and GV were treated with nimesulide (10 mg/kg per dose, five times per week for 8 weeks). Groups I, III, IV, and VI had 12 animals, and each of the other groups had 6 animals. All the animals were euthanized 8 weeks after the last dimethylhydrazine injection. The colons were fixed and processed for MT immunohistochemistry. The index of MT-overexpressing colonic crypts (MTEC) was estimated as the percentage of MT-stained crypts in relation to the total number of crypts scored. Five hundred crypts per animal were scored. Data were analyzed by the Kruskal-Wallis test followed by the Dunn test. There was an increase in MTEC index in the groups either infected with T. cruzi or treated with nimesulide or both infected and treated when compared to control (401, 809, and 1011 percent, respectively). We suggest that the increased formation of MTEC may be related to the protection against carcinogenesis provided both by T. cruzi infection and nimesulide.

Gene expression profiling in wild-type and metallothionein mutant fibroblast cell lines

The role of metallothioneins (MT) in copper homeostasis is of great interest, as it appears to be partially responsible for the regulation of intracellular copper levels during adaptation to extracellular excess of the metal. To further investigate a possible role of MTs in copper metabolism, a genomics approach was utilized to evaluate the role of MT on gene expression. Microarray analysis was used to examine the effects of copper overload in fibroblast cells from normal and MT I and II double knock-out mice (MT-/-). As a first step, we compared genes that were significantly upregulated in wild-type and MT-/- cells exposed to copper. Even though wild-type and mutant cells are undistinguishable in terms of their morphological features and rates of growth, our results show that MT-/- cells do not respond with induction of typical markers of cellular stress under copper excess conditions, as observed in the wild-type cell line, suggesting that the transcription initiation rate or the mRNA stability of stress genes is affected when there is an alteration in the copper store capacity. The functional classification of other up-regulated genes in both cell lines indicates that a large proportion (>80 percent) belong to two major categories: 1) metabolism; and 2) cellular physiological processes, suggesting that at the transcriptional level copper overload induces the expression of genes associated with diverse molecular functions. These results open the possibility to understand how copper homeostasis is being coordinated with other metabolic pathways.

Effect of dietary zinc deficiency on metallothionein concentration of epididymal luminal fluids of weanling Wistar albino rats.

Metallothionein (NIT) and zinc concentrations have been estimated in luminal fluids of caput/corpus and cauda epididymis and serum of zinc deficient (ZD), pairfed (PF) and control--ad libitum fed (ZC) groups of Wistar rats. MT decreased significantly in luminal fluids of caput corpus and cauda epididymis and serum of zinc deficient rats as compared to their respective controls. However, the decrease was non-significant in luminal fluids of corpus epididymis and serum of 4-weeks zinc deficient animals as compared to their control. Zinc levels also declined significantly in luminal fluids of epididymis and serum of zinc deficient rats as compared to their respective pairfed and control groups. Thus zinc deficiency state reduces zinc and MT concentrations in luminal fluid of epididymis and serum.

Nuclear zinc in liver of cadmium and zinc treated rats.

X-ray microanalysis was performed to detect quantitatively, the variation of the nuclear zinc in the liver cells of rats. The nuclear zinc concentration showed statistical decrease and increase in response to cadmium and zinc treatments, respectively. The results suggest that the liver responds differently to cadmium and zinc treatments. The difference in response to either treatment may reflect different mechanisms of zinc transport and metabolism in the liver. The difference in binding affinity of metallothionein (MT) may suggest the involvement of Mt in the metabolism and transport of zinc, an effect, which may be modified by treatment.

Effect of cadmium and zinc-metallothionein on methemoglobin and nitric oxide in dimethylnitrosamine treated rats.

Protective effects of metallothionein (MT) have been studied against dimethylnitosamine (DMN) toxicity in laboratory rats. MT was induced by feeding rats on repeated sublethal doses of cadmium and zinc. These rats were subsequently administered DMN. Methemoglobin and nitric oxides, the established markers of DMN toxicity, were estimated in the blood samples of MT protected rats. Preinduction of MT decreased methemoglobin and ameliorated the generation of nitric oxides. Antioxidative effects of MT may have manifested these results, however, an effect on N-nitrosation is also speculated.

Metalotioneínas e neoplasias humanas / Metallothioneins and human neoplasms

As metalotioneínas (MTs) säo uma família de proteínas de baixo peso molecular, ricas em cisteína e com ligaçöes seletivas a metais pesados. A expressäo das MTs em tecido, detectada através de técnica imuno-histoquímica, tem se correlacionado com comportamento agressivo de alguns cânceres humanos, dentre eles o carcinoma invasivo da mama e o melanoma. Esta revisäo tem como objetivo introduzir entre os patologistas noçöes básicas sobre a biologia das MTs, apresentar as características de sua expressäo em tecidos humanos e sua relaçäo com o comportamento biológico de algumas neoplasias, principalmente o carcinoma de mama

Correlation of metal distribution, reduced glutathione and metallothionein levels in liver and kidney of rat.

Effect of group IIB metals on the endogenous status of metallothionein (MT) and reduced glutathione (GSH) was studied in two vital detoxifying organs namely, liver and kidney of rat. The metals were administered at non lethal levels (1/10 LD50) which were found to cause no death. Zinc showed accumulation in both liver and kidney, cadmium preferentially in the liver while mercury in the kidney. Hepatic MT content was increased by 18-fold, 15-fold and 2-fold by cadmium, zinc and mercury respectively while renal MT was increased maximally by zinc. Among the metals, mercury caused highest depletion of hepatic GSH level (51%). The renal GSH showed differential response to the metal treatment, the level increasing slightly by cadmium and depleting significantly by zinc and mercury. A positive correlation was found between group IIB metal accumulation and the manifestation of toxic response.

Effect of Dexamethasone and Epinephrine on Metallothionein Level in the Perfused Rat Liver

The effect of dexamethasone (10(-5)M) and epinephrine (10(-6)M) on the biosynthesis of metallothionein (MT) in the perfused rat liver was investigated. MT synthesis was determined by measuring the incorporation of 14C-L-aspartic acid into liver MT fraction after the perfusion for five hours of isolated liver by artificial blood containing 14C-L-U-aspartic acid (0.2uci) with dexamethasone or epinephrine. MT was isolated by Sephadex G-75 column chromatography and DEAE Sephadex column chromatography. Incorporation of radioactive 14C into the MT fraction of perfused liver cytosol (9.0grams of liver) from dexamethasone treated, epinephrine treated and control groups were, respective1y, 0.72, 0.34 and 0.33% of total radioactivity infused. Total protein content in the MT fraction of liver perfused with dexamethasone and epinephrine were 0.80, 0.64mg/g liver compared to 0.52mg/g liver in the control. MT, a protein having a high content of cystein and metals is synthesized in the perfused rat liver and its induction is stimulated by dexamethasone, while epinephrine increased the accumulation of Zn in the MT fraction of the perfused rat liver. The present experiment confirms that MT synthesis and degradation are somewhat regulated by glucocorticoid hormone and epinephrine.