Molecular adaptations of NADP-malic enzyme for its function in C4 photosynthesis in grasses.

In C4 grasses of agronomical interest, malate shuttled into the bundle sheath cells is decarboxylated mainly by nicotinamide adenine dinucleotide phosphate (NADP)-malic enzyme (C4-NADP-ME). The activity of C4-NADP-ME was optimized by natural selection to efficiently deliver CO2 to Rubisco. During its evolution from a plastidic non-photosynthetic NADP-ME, C4-NADP-ME acquired increased catalytic efficiency, tetrameric structure and pH-dependent inhibition by its substrate malate. Here, we identified specific amino acids important for these C4 adaptions based on strict differential conservation of amino acids, combined with solving the crystal structures of maize and sorghum C4-NADP-ME. Site-directed mutagenesis and structural analyses show that Q503, L544 and E339 are involved in catalytic efficiency; E339 confers pH-dependent regulation by malate, F140 is critical for the stabilization of the oligomeric structure and the N-terminal region is involved in tetramerization. Together, the identified molecular adaptations form the basis for the efficient catalysis and regulation of one of the central biochemical steps in C4 metabolism.

Nutritional evaluation of sorghums grown with different organic fertilizers for slow-growing broilers / Avaliação nutricional do sorgo cultivado com diferentes adubos orgânicos para frangos de crescimento lento

The aim of this study was to evaluate the effects of sorghums grown with different organic fertilizers on the chemical composition, energy values, and nutrient metabolizability coefficients, as well as their use for feeding slow-growing broilers. Two trials were performed. In the first experiment, 200 21-day-old broilers were distributed in a completely randomized design (CRD), with five treatments and four replicates of 10 birds per experimental unit. The treatments consisted of a control diet and four test diets (sorghum fertilized with crotalaria, sorghum fertilized with millet, sorghum fertilized with humus, and sorghum without fertilization), including sorghum at 30% in the control diet. The apparent metabolizable energy (AME), apparent metabolizable energy corrected for nitrogen balance (AMEn), metabolizability coefficients of dry matter, crude protein, and gross energy were evaluated. In trial 2, 200 1-day-old chicks were used in a CRD with five treatments (T1 control diet with commercial corn, T2 sorghum fertilized with crotalaria, T3 sorghum fertilized with millet, T4 sorghum fertilized with humus, and T5 sorghum without fertilization) and four replicates of 10 birds per experimental unit. Weight gain, feed intake, feed conversion, and final weight at 28 days were evaluated. The values of AME and AMEn of sorghums fertilized with crotalaria, millet, humus, and sorghum without fertilization were 2894 Kcalkg-1 and 2881 Kcal kg-1; 2736 Kcal kg-1 and 2675 Kcal kg-1; 2727 Kcal kg-1 and 2694 Kcal kg-1; and 2994Kcal kg-1 and 2959 Kcal kg-1, respectively. The metabolizable coefficients of dry matter, crude protein, and gross energy were 76.04%, 42.01%, and 75.25% for sorghum fertilized with crotalaria; 77.50%, 50.77%, and 75.95% for sorghum fertilized with millet; 77.62%, 46.39%, and 75.54% for sorghumfertilized with humus; and 75.83%, 39.53%, and 74.71% for sorghum cultivated without fertilization,respectively. The dietary use of sorghum cultivated...(AU)

Objetivou-se no presente trabalho avaliar o sorgo cultivado com diferentes adubos orgânicos sobre a composição química, valores energéticos, coeficientes de metabolizabilidade dos nutrientes e sua utilização na alimentação de frangos de crescimento lento. Foram realizados dois experimentos, no primeiro foram utilizadas 200 aves de 21 dias de idade, distribuídas em delineamento inteiramente casualizado (DIC), com cinco tratamentos e quatro repetições de 10 aves por unidade experimental. Os tratamentos consistiram de uma dieta referência e quatro dietas testes (sorgo adubado com crotalária, sorgo adubado com milheto, sorgo adubado com húmus e sorgo sem adubação), na qual os sorgos substituíram 30% da dieta referência. Foram avaliados a energia metabolizável aparente (EMA), energia metabolizável aparente corrigida para o balanço de nitrogênio (EMAn), os coeficientes de metabolizabilidade da matéria seca, proteína bruta e energia bruta. No ensaio de desempenho, foram utilizados 200 pintos de 1 dia de idade, distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos (T1 - ração referência com milho comercial, T2 ração com sorgo adubado com crotalária, T3 ração com sorgo adubado com milheto, T4 ração com sorgo adubado com húmus e T5 ração com sorgo sem adubação) e quatro repetições de 10 aves por unidade experimental. Foram avaliados o ganho de peso, consumo de ração, conversão alimentar e o peso finalaos 28 dias. Os valores determinados de EMA e EMAn dos sorgos adubados com crotalária, milheto,húmus e o sorgo sem adubação foram de 2894 Kcal kg-1 e 2881 Kcal kg-1; 2736 Kcal kg-1 e 2675 Kcalkg-1; 2727 Kcal kg-1 e 2694 Kcal kg-1; 2994 Kcal kg-1 e 2959 Kcal kg-1, respectivamente, e os coeficientesde metabolizabilidade da MS, PB e EB foram: 76,04%, 42,01% e 75,25% para o sorgo adubado comcrotalária; 77,50%, 50,77% e 75,95% para o sorgo adubado com milheto; 77,62%, 46,39% e 75,54%para o sorgo adubado com húmus e 75,83%, 39,53% e...(AU)

Nutritional evaluation of sorghums grown with different organic fertilizers for slow-growing broilers / Avaliação nutricional do sorgo cultivado com diferentes adubos orgânicos para frangos de crescimento lento

The aim of this study was to evaluate the effects of sorghums grown with different organic fertilizers on the chemical composition, energy values, and nutrient metabolizability coefficients, as well as their use for feeding slow-growing broilers. Two trials were performed. In the first experiment, 200 21-day-old broilers were distributed in a completely randomized design (CRD), with five treatments and four replicates of 10 birds per experimental unit. The treatments consisted of a control diet and four test diets (sorghum fertilized with crotalaria, sorghum fertilized with millet, sorghum fertilized with humus, and sorghum without fertilization), including sorghum at 30% in the control diet. The apparent metabolizable energy (AME), apparent metabolizable energy corrected for nitrogen balance (AMEn), metabolizability coefficients of dry matter, crude protein, and gross energy were evaluated. In trial 2, 200 1-day-old chicks were used in a CRD with five treatments (T1 control diet with commercial corn, T2 sorghum fertilized with crotalaria, T3 sorghum fertilized with millet, T4 sorghum fertilized with humus, and T5 sorghum without fertilization) and four replicates of 10 birds per experimental unit. Weight gain, feed intake, feed conversion, and final weight at 28 days were evaluated. The values of AME and AMEn of sorghums fertilized with crotalaria, millet, humus, and sorghum without fertilization were 2894 Kcalkg-1 and 2881 Kcal kg-1; 2736 Kcal kg-1 and 2675 Kcal kg-1; 2727 Kcal kg-1 and 2694 Kcal kg-1; and 2994Kcal kg-1 and 2959 Kcal kg-1, respectively. The metabolizable coefficients of dry matter, crude protein, and gross energy were 76.04%, 42.01%, and 75.25% for sorghum fertilized with crotalaria; 77.50%, 50.77%, and 75.95% for sorghum fertilized with millet; 77.62%, 46.39%, and 75.54% for sorghumfertilized with humus; and 75.83%, 39.53%, and 74.71% for sorghum cultivated without fertilization,respectively. The dietary use of sorghum cultivated...

Objetivou-se no presente trabalho avaliar o sorgo cultivado com diferentes adubos orgânicos sobre a composição química, valores energéticos, coeficientes de metabolizabilidade dos nutrientes e sua utilização na alimentação de frangos de crescimento lento. Foram realizados dois experimentos, no primeiro foram utilizadas 200 aves de 21 dias de idade, distribuídas em delineamento inteiramente casualizado (DIC), com cinco tratamentos e quatro repetições de 10 aves por unidade experimental. Os tratamentos consistiram de uma dieta referência e quatro dietas testes (sorgo adubado com crotalária, sorgo adubado com milheto, sorgo adubado com húmus e sorgo sem adubação), na qual os sorgos substituíram 30% da dieta referência. Foram avaliados a energia metabolizável aparente (EMA), energia metabolizável aparente corrigida para o balanço de nitrogênio (EMAn), os coeficientes de metabolizabilidade da matéria seca, proteína bruta e energia bruta. No ensaio de desempenho, foram utilizados 200 pintos de 1 dia de idade, distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos (T1 - ração referência com milho comercial, T2 ração com sorgo adubado com crotalária, T3 ração com sorgo adubado com milheto, T4 ração com sorgo adubado com húmus e T5 ração com sorgo sem adubação) e quatro repetições de 10 aves por unidade experimental. Foram avaliados o ganho de peso, consumo de ração, conversão alimentar e o peso finalaos 28 dias. Os valores determinados de EMA e EMAn dos sorgos adubados com crotalária, milheto,húmus e o sorgo sem adubação foram de 2894 Kcal kg-1 e 2881 Kcal kg-1; 2736 Kcal kg-1 e 2675 Kcalkg-1; 2727 Kcal kg-1 e 2694 Kcal kg-1; 2994 Kcal kg-1 e 2959 Kcal kg-1, respectivamente, e os coeficientesde metabolizabilidade da MS, PB e EB foram: 76,04%, 42,01% e 75,25% para o sorgo adubado comcrotalária; 77,50%, 50,77% e 75,95% para o sorgo adubado com milheto; 77,62%, 46,39% e 75,54%para o sorgo adubado com húmus e 75,83%, 39,53% e...

Effects of sorghum on broilers gastrointestinal tract

This study aimed at evaluating the effects of whole and ground sorghum, compared with ground corn, on the live weight, feed conversion ratio, organs weight and intestinal biometrics and histomorphometrics. In total, 960 Hubbard Flex broilers were reared until 42-day-old and distributed into 24 pens, according to the three treatments: ground corn, whole-grain sorghum, and ground sorghum. On day 42, five male birds per treatment were selected by similar body weight and sacrificed. Gizzard absolute weight, and proventriculus, liver, pancreas and heart relative weights, and duodenum, jejunum, ileum, ceca, and colon length and relative weight were determined. Villus characteristics and intestinal mucosa absorption surface area were evaluated. Broilers fed sorghum, independently of physical form, were heavier and had greater feed conversion ratio than those fed ground corn. Gizzard showed the highest relative weight in broilers fed whole sorghum compared to corn. Liver and jejunum relative weight was higher in broilers fed ground corn, compared to ground sorghum. Whole small intestine, cecum and colon relative lengths showed no difference among treatments. Deeper crypts were found in the duodenum of broilers fed whole grain sorghum, compared to ground sorghum, as well as in jejunum compared to ground corn; however, intestinal absorption surface area was not different among treatments. Whole or ground grain sorghum may replace corn in the feed of 1- to 42-d-old broilers, since they improve body weight and feed conversion ratio, and not adversely affect intestinal morphometry and organs weight.(AU)

Effects of sorghum on broilers gastrointestinal tract

This study aimed at evaluating the effects of whole and ground sorghum, compared with ground corn, on the live weight, feed conversion ratio, organs weight and intestinal biometrics and histomorphometrics. In total, 960 Hubbard Flex broilers were reared until 42-day-old and distributed into 24 pens, according to the three treatments: ground corn, whole-grain sorghum, and ground sorghum. On day 42, five male birds per treatment were selected by similar body weight and sacrificed. Gizzard absolute weight, and proventriculus, liver, pancreas and heart relative weights, and duodenum, jejunum, ileum, ceca, and colon length and relative weight were determined. Villus characteristics and intestinal mucosa absorption surface area were evaluated. Broilers fed sorghum, independently of physical form, were heavier and had greater feed conversion ratio than those fed ground corn. Gizzard showed the highest relative weight in broilers fed whole sorghum compared to corn. Liver and jejunum relative weight was higher in broilers fed ground corn, compared to ground sorghum. Whole small intestine, cecum and colon relative lengths showed no difference among treatments. Deeper crypts were found in the duodenum of broilers fed whole grain sorghum, compared to ground sorghum, as well as in jejunum compared to ground corn; however, intestinal absorption surface area was not different among treatments. Whole or ground grain sorghum may replace corn in the feed of 1- to 42-d-old broilers, since they improve body weight and feed conversion ratio, and not adversely affect intestinal morphometry and organs weight.

Plastidial NADP-malic enzymes from grasses: unraveling the way to the C4 specific isoforms.

Malic enzyme is present in many plant cell compartments such as plastids, cytosol and mitochondria. Particularly relevant is the plastidial isoform that participates in the C(4) cycle providing CO(2) to RuBisCO in C(4) species. This type of photosynthesis is more frequent among grasses where anatomical preconditioning would have facilitated the evolution of the C(4) syndrome. In maize (C(4) grass), the photosynthetic NADP dependent Malic enzyme (ZmC(4)-NADP-ME, l-malate:NADP oxidoreductase, E.C. 1.1.1.40) and the closest related non-photosynthetic isoform (ZmnonC(4)-NADP-ME, l-malate:NADP oxidoreductase, E.C. 1.1.1.40) are both plastidial but differ in expression pattern, kinetics and structure. Features like high catalytic efficiency, inhibition by high malate concentration at pH 7.0, redox modulation and tetramerization are characteristic of the photosynthetic NADP-ME. In this work, the proteins encoded by sorghum (C(4) grass) and rice (C(3) grass) NADP-ME genes, orthologues of the plastidial NADP-MEs from maize, were recombinantly expressed, purified and characterized. In a global comparison, we could identify a small group of residues which may explain the special features of C(4) enzymes. Overall, the present work presents biochemical and molecular data that helps to elucidate the changes that took place in the evolution of C(4) NADP-ME in grasses.

Fermentation and enzyme treatments for sorghum

Sorghum (Sorghum bicolor Moench) is the fifth most produced cereal worldwide. However, some varieties of this cereal contain antinutritional factors, such as tannins and phytate that may form stable complexes with proteins and minerals which decreases digestibility and nutritional value. The present study sought to diminish antinutritional tannins and phytate present in sorghum grains. Three different treatments were studied for that purpose, using enzymes tannase (945 U/Kg sorghum), phytase (2640 U/Kg sorghum) and Paecilomyces variotii (1.6 X 10(7) spores/mL); A) Tannase, phytase and Paecilomyces variotii, during 5 and 10 days; B) An innovative blend made of tanase and phytase for 5 days followed by a Pv increase for 5 more days; C) a third treatment where the reversed order of B was used starting with Pv for 5 days and then the blend of tannase and phytase for 5 more days. The results have shown that on average the three treatments were able to reduce total phenols and both hydrolysable and condensed tannins by 40.6, 38.92 and 58.00 %, respectively. Phytase increased the amount of available inorganic phosphorous, on the average by 78.3 %. The most promising results concerning tannins and phytate decreases were obtained by the enzymes combination of tannase and phytase. The three treatments have shown effective on diminishing tannin and phytate contents in sorghum flour which leads us to affirm that the proposed treatments can be used to increase the nutritive value of sorghum grains destined for either animal feeds or human nutrition.

Expression of seed dormancy in grain sorghum lines with contrasting pre-harvest sprouting behavior involves differential regulation of gibberellin metabolism genes.

Grain sorghum [Sorghum bicolor (L) moench] exhibits intraspecific variability for the rate of dormancy release and pre-harvest sprouting behavior. Two inbred lines with contrasting sprouting response were compared: IS9530 (resistant) and RedlandB2 (susceptible). Precocious dormancy release in RedlandB2 is related to an early loss of embryo sensitivity to ABA and higher levels of gibberellins in imbibed grains as compared with IS9530. With the aim of identifying potential regulatory sites for gibberellin metabolism involved in the expression of dormancy in immature grains of both lines, we carried out a time course analysis of transcript levels of putative gibberellin metabolism genes and hormone content (GA(1), GA(4), GA(8) and GA(34)). A lower embryonic GA(4) level in dormant IS9530 was related to a sharp and transient induction of two SbGA2-oxidase (inactivation) genes. In contrast, these genes were not induced in less dormant RedlandB2, while expression of two SbGA20-oxidase (synthesis) genes increased together with active GA(4) levels before radicle protrusion. Embryonic levels of GA(4) and its catabolite GA(34) correlated negatively. Thus, in addition to the process of gibberellin synthesis, inactivation is also important in regulating GA(4) levels in immature grains. A negative regulation by gibberellins was observed for SbGA20ox2, SbGA2ox1 and SbGA2ox3 and also for SbGID1 encoding a gibberellin receptor. We propose that the coordinated regulation at the transcriptional level of several gibberellin metabolism genes identified in this work affects the balance between gibberellin synthesis and inactivation processes, controlling active GA(4) levels during the expression of dormancy in maturing sorghum grains.

Evaluation of sorghum straw hemicellulosic hydrolysate for biotechnological production of xylitol by Candida guilliermondii

A preliminary study on xylitol production by Candida guilliermondii in sorghum straw hemicellulosic hydrolysate was performed. Hydrolysate had high xylose content and inhibitors concentrations did not exceed the commonly found values in other hemicellulosic hydrolysates. The highest xylitol yield (0.44 g/g) and productivity (0.19 g/Lh) were verified after 72 hours.

NH(4)(+)-stimulated low-K(+) uptake is associated with the induction of H(+) extrusion by the plasma membrane H(+)-ATPase in sorghum roots under K(+) deficiency.

The effect of external inorganic nitrogen and K(+) content on K(+) uptake from low-K(+) solutions and plasma membrane (PM) H(+)-ATPase activity of sorghum roots was studied. Plants were grown for 15 days in full-nutrient solutions containing 0.2 or 1.4mM K(+) and inorganic nitrogen as NO(3)(-), NO(3)(-)/NH(4)(+) or NH(4)(+) and then starved of K(+) for 24, 48 and 72 h. NH(4)(+) in full nutrient solution significantly affected the uptake efficiency and accumulation of K(+), and this effect was less pronounced at the high K(+) concentration. In contrast, the translocation rate of K(+) to the shoot was not altered. Depletion assays showed that plants grown with NH(4)(+) more efficiently depleted the external K(+) and reached higher initial rates of low-K(+) uptake than plants grown with NO(3)(-). One possible influence of K(+) content of shoot, but not of roots, on K(+) uptake was evidenced. Enhanced K(+)-uptake capacity was correlated with the induction of H(+) extrusion by PM H(+)-ATPase. In plants grown in high K(+) solutions, the increase in the active H(+) gradient was associated with an increase of the PM H(+)-ATPase protein concentration. In contrast, in plants grown in solutions containing 0.2mM K(+), only the initial rate of H(+)-pumping and ATP hydrolysis were affected. Under these conditions, two specific isoforms of PM H(+)-ATPase were detected, independent of the nitrogen source and deficiency period. No change in enzyme activity was observed in NO(3)(-)-grown plants. The results suggest that K(+) homeostasis in NH(4)(+)-grown sorghum plants may be regulated by a high capacity for K(+) uptake, which is dependent upon the H(+)-pumping activity of PM H(+)-ATPase.

Isolation and characterization of enzymes involved in lysine catabolism from sorghum seeds.

Lysine is an essential amino acid synthesized in plants via the aspartic acid pathway. The catabolism of lysine is performed by the action of two consecutive enzymes, lysine 2-oxoglutarate reductase (LOR, EC 1.5.1.8) and saccharopine dehydrogenase (SDH, EC 1.5.1.9). The final soluble lysine concentration in cereal seeds is controlled by both synthesis and catabolism rates. The production and characterization of high-lysine plants species depends on knowledge of the regulatory aspects of lysine metabolism and manipulation of the key enzymes. We have for the first time isolated, partially purified, and characterized LOR and SDH from developing sorghum seeds, which exhibited low levels of activity. LOR and SDH were only located in the endosperm and were very unstable during the isolation and purification procedures. LOR and SDH exhibited some distinct properties when compared to the enzymes isolated from other plant species, including a low salt concentration required to elute the enzymes during anion-exchange chromatography and the presence of multimeric forms with distinct molecular masses.