A new strategy for improved glutathione production from Saccharomyces cerevisiae: use of cysteine‐ and glycine‐rich chicken feather protein hydrolysate as a new cheap substrate

BACKGROUND: Glutathione (GSH) is composed of the amino acids glutamic acid, cysteine and glycine. This study investigated the usability of chicken feather protein hydrolysate (chicken feather peptone, CFP) as a substrate for GSH production from Saccharomyces cerevisiae. RESULTS: CFP was found to be rich in ash (36.7 g per 100 g), protein (61.1 g per 100 g) and minerals (S, P, K, Ca, Fe, Na and Mg). It also had high contents of cysteine and glycine. CFP augmented biomass and GSH production by 53 and 115% respectively compared with the control medium. The highest biomass (17.4 g l^?1) and GSH (271 mg L^?1) concentrations were attained in CFP medium. The second highest biomass (16.8 g l^?1) and GSH (255 mg L^?1) concentrations were obtained in fish peptone medium. It was assumed that the high mineral, cysteine and glycine contents of CFP were related to cell growth and GSH synthesis in S. cerevisiae. CONCLUSION: This is the first report on the effect of cysteine‐ and glycine‐rich protein hydrolysates on GSH production from S. cerevisiae. In this regard, CFP was tested for the first time as a GSH production substrate. As an additional contribution, a new hydrolysis process was developed for the preparation of protein hydrolysates. © 2012 Society of Chemical Industry     

The ALD6 gene of Saccharomyces cerevisiae encodes a cytosolic,Mg2+-activated acetaldehyde dehydrogenase

The deduced translation product of an open reading frame on the left arm of chromosome XVI of Saccharomyces cerevisiae, with the systematic name of YPL061w, is 500 amino acids in length and shares significant homology with aldehyde dehydrogenases. Amino acids 2 to 16 of the protein encoded by YPL061w were found to be identical to the N-terminal 15 amino acids of the purified cytosolic, Mg²⁺-activated acetaldehyde dehydrogenase (ACDH) of S. cerevisiae. This enzyme is thought to be involved in the production of acetate from which cytosolic acetyl-CoA is then synthesized. Deletion of YPL061w was detrimental to the growth of haploid strains of yeast; an analysis of one deletion mutant revealed a maximum specific growth rate (in complex medium containing glucose) of one-third of that displayed by the wild-type strain. Mutants deleted in YPL061w were also unable to use ethanol as a carbon source. As expected, the cytosolic, Mg²⁺-activated ACDH activity had been lost from the mutants, although the mitochondrial, K⁺-activated ACDH was readily detected. YPL061w has been registered with the name of ALD6 in the Saccharomyces Genome Database and the nucleotide sequence submitted to GenBank as part of accession number U39205. © 1997 John Wiley & Sons, Ltd.     

Growing Azolla to produce sustainable protein feed: the effect of differing species and CO2 concentrations on biomass productivity and chemical composition

BACKGROUND

Since available arable land is limited and nitrogen fertilizers pollute the environment, cropping systems ought to be developed that do not rely on them. Here we investigate the rapidly growing, N₂‐fixing Azolla/Nostoc symbiosis for its potential productivity and chemical composition to determine its potential as protein feed.

RESULTS

In a small production system, cultures of Azolla pinnata and Azolla filiculoides were continuously harvested for over 100 days, yielding an average productivity of 90.0–97.2 kg dry weight (DW) ha^?1 d^?1. Under ambient CO₂ levels, N₂ fixation by the fern's cyanobacterial symbionts accounted for all nitrogen in the biomass. Proteins made up 176–208 g kg^?1 DW (4.9 × total nitrogen), depending on species and CO₂ treatment, and contained more essential amino acids than protein from soybean. Elevated atmospheric CO₂ concentrations (800 ppm) significantly boosted biomass production by 36–47%, without decreasing protein content. Choice of species and CO₂ concentrations further affected the biomass content of lipids (79–100 g kg^?1 DW) and (poly)phenols (21–69 g kg^?1 DW).

CONCLUSIONS

By continuous harvesting, high protein yields can be obtained from Azolla cultures, without the need for nitrogen fertilization. High levels of (poly)phenols likely contribute to limitations in the inclusion rate of Azolla in animal diets and need further investigation. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

     

Amino acid profiles and protein quality of cooked cassava leaves or ‘saka‐saka’

Cassava (Manihot esculenta Crantz) leaves form the main source of protein in a diet consisting of processed cassava roots as sole staple food in konzo‐affected areas of the Democratic Republic of Congo. Pounded cassava leaves were hydrolysed and analysed by HPLC before and after cooking to assess amino acid profiles and protein quality. An average of about 58% loss of total protein content was observed in five different cooked samples. The protein content in cassava leaves was high, an average of 285.9 g kg^?1 dry weight in the raw and 119.2 g kg^?1 dry weight in the cooked samples, but of poor quality, with sulphur amino acids as the most limiting amino acids. Lysine and leucine were also limiting amino acids in some of the raw samples. Lysine, histidine, leucine and isoleucine were limiting amino acids in the cooked samples besides the sulphur amino acids. The consumption of cassava leaves does not compensate the dietary deficiency of sulphur amino acids in the roots that are the staple food in konzo‐affected areas. Sulphur amino acids are essential for detoxification of the residual cyanogens remaining in insufficiently processed cassava roots. Cereals and legumes, as sources of sulphur amino acids and lysine respectively, should be promoted as part of the diet in those areas to prevent the paralytic neuro‐toxico‐nutritional disease konzo among the poor population. Copyright © 2003 Society of Chemical Industry     

Wet‐fractionation of Phaseolus lunatus seeds: partial characterization of starch and protein

The optimum extraction conditions for integral use of Phaseolus lunatus seed, in alkaline medium, are 1:6 (w/v) flour:water ratio, pH 11 and a 1 h extraction time. Three main fractions were produced under these conditions: starch; protein isolate and fibrous residue by‐product. The yield is 288.4 g kg^?1 starch, 188.2 g kg^?1 protein isolate and the remaining quantity, fibrous residue. The starch has 98.4% purity, a 75 °C gelatinization temperature and high syneresis even at high concentrations. It also has high viscosity, good stability and middle retrogradation during the heating–cooling cycle. The protein isolate contains 711.3 g kg^?1 protein as well as 75.5 g lysine kg^?1 protein, 10.1 g methionine kg^?1 protein and 12.2 g tryptophan kg^?1 protein. Its in vitro digestibility is 79% with a 2.5 c‐PER. The fibrous residue contains 63 g kg^?1 of protein, 328.4 g kg^?1 of crude fiber and 567.3 g kg^?1 of NFE. Copyright © 2004 Society of Chemical Industry     

Simultaneous utilization of ammonia,free amino acids and peptides during fermentative growth of Saccharomyces cerevisiae

The efficiency of nitrogen use by yeast is one of the key determinants of the successful completion of alcoholic fermentations. In this work the growth of Saccharomyces cerevisiae S288c in a synthetic medium containing ammonia and free amino acids, supplemented with yeast hydrolysate, was studied. Experiments with ¹⁵NH₄Cl and ¹⁵N‐labelled yeast hydrolysate were carried out to gain insight into which of these three classes of assimilable nitrogen sources yeast cells prefer. Co‐consumption of all three sources was observed; approximately 40% of the total nitrogen in the yeast protein fraction originated from yeast hydrolysate, while free amino acids and ammonia contributed 40 and 20%, respectively. The results indicate that several amino acids are more readily obtained from peptides, most likely when the uptake of their free forms is competitively inhibited and/or repressed. During the second half of each fermentation, a decrease in the incorporation of yeast hydrolysate‐derived nitrogen was observed. These results highlight the nutritional role of peptides in various yeast fermentations. Copyright © 2016 The Institute of Brewing & Distilling     

Chemical composition,protein fractionation,essential amino acid potential and antimetabolic constituents of an unconventional legume,Gila bean (Entada phaseoloides Merrill) seed kernel

Physical characteristics of pods and seeds, proximate composition, different protein fractionation, SDS‐PAGE analysis of proteins, amino acid composition, starch content, fatty acid profiles and various antimetabolic substances of Gila bean (Entada phaseoloides Merrill) were studied. The pod length and the number of seeds per pod ranged from 55 to 90 cm and from 5 to 11 respectively. The kernel comprised 66.1% of the seed weight (18.41 ± 1.14 g). The seed kernels contained 256.7 g kg^?1 crude protein, 108.1 g kg^?1 lipid, 27.3 g kg^?1 ash and a high content of carbohydrate (585.7 g kg^?1). The levels of potassium, phosphorus, zinc and iron were similar to those in conventional pulses. Among the different protein fractions of seed kernels, albumins constituted the major storage proteins (69.7%). The kernel proteins were rich in essential amino acids, particularly sulphur‐containing amino acids, and their values appeared to be higher than the FAO/WHO (1990) reference protein for a 2–5‐year‐old growing child and soybean, and comparable to hen egg. Seed kernel lipids contained high levels of unsaturated fatty acids, oleic and linoleic acids, which accounted for 83% of the total fatty acid recovered. The kernel exhibited high trypsin and chymotrypsin inhibitor activities (96.65 mg TI g^?1 and 30.02 CIU mg^?1 sample respectively) in addition to containing phenolics, phytic acid, lectins and oligosaccharides. Another major toxic constituent was identified as a group of triterpenoid saponins (3.21%), which had high haemolytic activity (HeU) against cattle erythrocytes and caused high mortality in fish. The in vitro digestibility of the kernel protein was low (67%). © 2001 Society of Chemical Industry     

Response of laying Japanese quails to graded levels of essential amino acids profile with reduced dietary protein

The effect on egg production of graded levels of ideal amino acids, combined with reduced protein in the diet, was investigated in 312 laying quails aged 6–18 weeks. The quails were offered six diets, each of which contained one of three levels of amino acids (85, 100 and 115% of essential amino acids (EAAs)) together with 5% or without fishmeal (FM) (3 × 2 factorial design). Each diet was offered to 26 replicated groups of two quails each. Hen‐day and hen‐housed egg production did not differ as a result of EAA level, protein type or their interaction during the overall period of egg production. Egg weight improved linearly (P < 0.01) with increased EAA levels, while egg mass output per bird per day remained similar at the 100 and 115% EAA levels. Quails fed higher (100 and 115%) EAA levels had an improved feed conversion ratio (P < 0.01) compared to birds fed 85% EAA. The gain in body weight during the laying period was higher (P < 0.01) at the 100 or 115% than at 85% EAA levels The ratio of egg mass or egg mass and live weight gain, together, to protein intake improved (P < 0.01) linearly with a decrease in EAA levels in the diets, while better (P < 0.01) energy efficiency (EE, energy intake: egg mass) and net EE (energy intake: egg mass plus gain) was obtained in higher EAA levels (100 or 115%). Protein and energy efficiencies remained similar due to protein type or interaction. Shape index, albumen index, yolk index, yolk colour and relative shell weight did not differ due to EAA levels, protein type or their interaction. Eggs laid from quails fed diets with 100% EAAs without FM and 115% EAAs with or without FM had higher shell thickness than those on 85% EAAs irrespective of protein type. The retention of nitrogen and calcium retention was higher (P < 0.01) at the 115% EAA level. The results indicated a dietary level of 100% EAA (185 g kg^?1 crude protein (CP)) with 12.13 MJ kg^?1 was suitable for laying quails of 6–18 weeks of age. Copyright © 2007 Society of Chemical Industry     

Industrial potential of carotenoid pigments from microalgae: Current trends and future prospects

Microalgae are rich source of various bioactive molecules such as carotenoids, lipids, fatty acids, hydrocarbons, proteins, carbohydrates, amino acids, etc. and in recent Years carotenoids from algae gained commercial recognition in the global market for food and cosmeceutical applications. However, the production of carotenoids from algae is not yet fully cost effective to compete with synthetic ones. In this context the present review examines the technologies/methods in relation to mass production of algae, cell harvesting for extraction of carotenoids, optimizing extraction methods etc. Research studies from different microalgal species such as Spirulina platensis, Haematococcus pluvialis, Dunaliella salina, Chlorella sps., Nannochloropsis sps., Scenedesmus sps., Chlorococcum sps., Botryococcus braunii and Diatoms in relation to carotenoid content, chemical structure, extraction and processing of carotenoids are discussed. Further these carotenoid pigments, are useful in various health applications and their use in food, feed, nutraceutical, pharmaceutical and cosmeceutical industries was briefly touched upon. The commercial value of algal carotenoids has also been discussed in this review. Possible recommendations for future research studies are proposed.     

Biochemical composition of two red seaweed species grown on the Brazilian coast

BACKGROUND: Algae species have been used as an important source of food because they are highly nutritive considering their vitamin, protein, mineral, fiber, essential fatty acid and carbohydrate contents. However, a large number of seaweeds have been poorly studied, especially Brazilian species. Two red macroalgae species from the Brazilian coast (Plocamium brasiliense and Ochtodes secundiramea) were assessed with respect to their total lipid, fatty acid, total nitrogen, protein, amino acid and total carbohydrate contents. RESULTS: The total lipid contents (dry weight) were 36.3 and 35.4 g kg^?1; fatty acid contents were 9.3 and 12.1 g kg^?1; total nitrogen contents were 37.4 and 24.9 g kg^?1; protein contents were 157.2 and 101.0 g kg^?1; amino acid contents were 127.5 and 91.4 g kg^?1; and total carbohydrate contents were 520.3 and 450.7 g kg^?1 for P. brasiliense and O. secundiramea, respectively. CONCLUSION: Considering these compositions, both algae species were determined to have sources of protein, essential amino acids and carbohydrates similar to the edible seaweeds Laminaria japonica and Palmaria palmata. Copyright © 2011 Society of Chemical Industry     

Low‐protein amino acid‐supplemented diets in broiler chickens: effects on performance,carcass characteristics,whole‐body composition and efficiencies of nutrient utilisation

Two concurrent trials were conducted to investigate the influence of low‐protein amino acid‐supplemented diets on the performance, carcass characteristics, whole‐body composition and efficiencies of nutrient utilisation by the male broiler chicken from age 3 to 6 weeks. The first trial comprised five isoenergetic (13.0 MJ kg⁻¹) diets containing 225 (control), 210, 190, 172 or 153 g kg⁻¹ crude protein (CP) supplemented with essential amino acids (EAAs) to meet the minimum National Research Council recommendations. In the second trial a composite mixture of non‐essential amino acids (NEAAs) was added to the lower‐CP diets (ie 210–153 g kg⁻¹) such that they became isoproteinous (N × 6.25) with the 225 g kg⁻¹ control. Neither the lowering of dietary CP nor NEAA supplementation had any significant influence on weight gain or the relative weights of the various carcass cuts. However, chicks fed the lowest‐CP diets consumed more feed (P ≤ 0.05) and had poorer (P ≤ 0.05) feed conversion efficiency (FCE). NEAA supplementation enhanced FCE to the control levels. Whole‐body compositional analysis showed that lowering dietary CP increased (P ≤ 0.01) total body fat in a linear fashion (P ≤ 0.001; r = −0.72). Equalising dietary CP with the control (ie maintaining identical energy/protein ratio) by NEAA supplementation did not correct for the fat deposition. Total body protein (g kg⁻¹) was identical with the control with or without NEAA supplementation. Dietary energy, protein retention efficiency (PRE) and protein efficiency ratio (PER) were more efficient (P ≤ 0.01) in the lower‐protein diets, while NEAA supplementation significantly (P ≤ 0.01) decreased the efficiency of N utilisation. Reducing dietary CP from 225 to 153 g kg⁻¹ decreased N excretion in a highly significant linear fashion (P ≤ 0.001; r = 0.73). The nutritional and environmental implications of the increased body fat deposition on the one hand and the decreased N excretion on the other in the low‐protein‐fed chickens are discussed and the need to harmonise these apparently conflicting interests is emphasised. © 2000 Society of Chemical Industry     

Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii

Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels.     

In vitro digestibility of protein and amino acids in protein mixtures

Six protein sources, casein, field peas, peanut meal, wheat flour, rapeseed and soya bean concentrate and their blends (ratio 1:1) were subjected to in vitro enzymic digestion. Wheat flour had the lowest in vitro digestibility (30% in 6 h) while the other sources had similar digestibilities (40%). Basic and aromatic amino acids were the most readily liberated from these protein sources. Some protein combinations, such as a rapeseed/field pea blend, gave in vitro digestibilities higher than calculated from individual proteins. The type of response observed could not be predicted from either nitrogen digestibility or amino acid composition of the individual sources. The digestibility of some amino acids was modified and this could be due to varying affinity of digestive enzymes for the protein.     

Nutritional evaluation of the fungus Phycomyces blakesleeanus as a protein source

The quality of the protein of the carotenogenic fungus Phycomyces blakesleeanus Burgeff, strain NRRL 1555 ( - ), was evaluated with rats and observed to have a protein efficiency ratio of 1.4. The limiting amino acids were tryptophan, sulphur-containing amino acids, lysine and isoleucine. Upon incorporation into diets containing 100 g kg⁻¹ protein the proportions of the above mentioned amino acids of the optimal recommended dietary allowances for growing rats were 33.0%, 57.4%, 74.5% and 87.2% respectively. Furthermore, the fungal protein was found to contain an excess of histidine about eight fold more than the recommended dietary allowance for growing rats. Some safety aspects were examined and, although the fungus was consumed in high dietary concentrations, 242 g kg⁻¹ of the diet, no pronounced toxicological effects were observed.     

Dicistronic regulation of fluorescent proteins in the budding yeast Saccharomyces cerevisiae

Fluorescent proteins are convenient tools for measuring protein expression levels in the budding yeast Saccharomyces cerevisiae. Co‐expression of proteins from distinct vectors has been seen by fluorescence microscopy; however, the expression of two fluorescent proteins on the same vector would allow for monitoring of linked events. We engineered constructs to allow dicistronic expression of red and green fluorescent proteins and found that expression levels of the proteins correlated with their order in the DNA sequence, with the protein encoded by the 5′‐gene more highly expressed. To increase expression levels of the second gene, we tested four regulatory elements inserted between the two genes: the IRES sequences for the YAP1 and p150 genes, and the promoters for the TEF1 gene from both S. cerevisiae and Ashbya gossypii. We generated constructs encoding the truncated ADH1 promoter driving expression of the red protein, yeast‐enhanced Cherry, followed by a regulatory element driving expression of the green protein, yeast‐enhanced GFP. Three of the four regulatory elements successfully enhanced expression of the second gene in our dicistronic construct. We have developed a method to express two genes simultaneously from one vector. Both genes are codon‐optimized to produce high protein levels in yeast, and the protein products can be visualized by microscopy or flow cytometry. With this method of regulation, the two genes can be driven in a dicistronic manner, with one protein marking cells harbouring the vector and the other protein free to mark any event of interest. Copyright © 2009 John Wiley & Sons, Ltd.     

Chemical compositions of the marine algae Gracilaria salicornia (Rhodophyta) and Ulva lactuca (Chlorophyta) as a potential food source

BACKGROUND: The nutritional compositions of two edible red (Gracilaria salicornia) and green (Ulva lactuca) seaweeds were determined to evaluate their possible uses as potential food ingredients. RESULTS: In general, these species contained limited amounts of lipids ranging between 0.99 and 2.00 g 100 g^?1 dry weight) and considerably high amount of minerals, especially in G. salicornia (38.91 g 100 g^?1 d.w.). The crude protein values varied between 9.58 and 10.69 g 100 g^?1 d.w. Amounts for total amino acids were 889.78 ± 22.64 mg g^?1 protein d.w. in G. salicornia and 543.3 ± 15.14 mg g^?1 protein d.w. in U. lactuca. The most abundant fatty acids were C12:0, C16:0, C20:4 ω6 and C22:5 ω3, in addition to C18:1 in G. salicornia. Both seaweed species were balanced sources of ω3 and ω6 fatty acids with a ratio of ω6/ω3 that varied between 1.2 and 1.17. Between the seaweeds investigated, high levels of K (2414.02‐11 380.06 mg 100 g^?1 d.w.) were observed and the amounts of Ca, Na and Fe were higher than those reported for land plants. CONCLUSIONS: Thus, G. salicornia and U. lactuca may be utilised as value‐added products for human nutrition purposes. Copyright © 2012 Society of Chemical Industry     

Nutritional Value and Use of the Andean Crops Quinoa (Chenopodium quinoa) and Kañiwa (Chenopodium pallidicaule)

Quinoa (Chenopodium quinoaWilld.) and kañiwa (Chenopodium pallidicauleAellen) are native food plants of high nutritional value grown in the Andean region and used as food by the Incas and previous cultures. Quinoa and kañiwa served as a substitute for scarce animal proteins and are still one of the principal protein sources of the region. The importance of these proteins is based on their quality, with a balanced composition of essential amino acids similar to the composition of casein, the protein of milk. According to studies at the Universidad Nacional Agraria La Molina (UNALM), quinoa and kañiwa have a very high chemical score, and one cultivar of quinoa, Amarilla de Marangani, does not have any limiting amino acid.

It is also important to recognize and utilize the relatively high quantity of oil in quinoa and kañiwa. These grains can be a potential raw material for oil extraction. The highest percentage of fatty acids present in these oils is Omega 6 (linoleic acid), being 50.2% for quinoa and 42.6% for kañiwa. The fatty acid composition is similar to corn germ oil. The concentrations of γ- and α-tocoferol were for quinoa 797.2 and 721.4 ppm, and for kañiwa 788.4 and 726 ppm, respectively.

Quinoa and kañiwa can been utilized in weaning food mixtures. Two dietary mixtures have been formulated: quinoa-kañiwa-beans and quinoa-kiwicha-beans, with high nutritional value. The mixtures had PER values close to that of casein: 2.36 and 2.59, respectively (casein 2.5). Also, elderly people and those with a need to lose weight can benefit from consumption of quinoa and kañiwa. The high content of dietary fiber has many positive health effects, for example, it can reduce the level of cholesterol in the blood and improve digestion. For this reason, consumers in developed countries may also have an interest in including quinoa into their diet.     

Amaranthus viridis Linn., a common spinach, modulates C-reactive protein, protein profile, ceruloplasmin and glycoprotein in experimental induced myocardial infarcted rats

BACKGROUND: Glycoprotein is one of the components of the cardiac extracellular matrix and plays an important role in cardiac remodelling during various cardiac diseases, including myocardial infarction (MI). This study was aimed at evaluating the preventive role of Amaranthus viridis Linn. on C‐reactive protein (CRP), total protein, albumin, globulin, ceruloplasmin and glycoproteins in the serum and heart of experimental induced myocardial infarcted (MI) rats. RESULTS: MI was induced in male Wistar rats by subcutaneous injection of 20 mg kg^?1 isoproterenol (ISO) kg^?1 body weight (BW) twice at an interval of 24 h. ISO‐induced MI rats showed a significant increase in the levels of serum CRP and ceruloplasmin and a significant decrease in the levels of serum total protein, albumin and globulin. Glycoprotein levels in the serum and heart were increased in ISO‐induced MI rats. Oral administration of 300 mg A. viridis kg^?1 BW day^?1 for a period of 45 days altered the metabolic derangement in ISO‐induced MI rats. CONCLUSION: This study exemplifies the protective effect of A. viridis on ISO‐induced cardiotoxicity in male Wistar rats. The data further reinforce the cardioprotective effect of A. viridis by altering CRP and glycoprotein levels. Copyright © 2012 Society of Chemical Industry     

Isolation and characterization of the carbon catabolite‐derepressing protein kinase Snf1 from the stress tolerant yeast Torulaspora delbrueckii

We cloned a genomic DNA fragment of the yeast Torulaspora delbrueckii by complementation of a Saccharomyces cerevisiae snf1Δ mutant strain. DNA sequence analysis revealed that the fragment contained a complete open reading frame (ORF), which shares a high similarity with the S. cerevisiae energy sensor protein kinase Snf1. The cloned TdSNF1 gene was able to restore growth of the S. cerevisiae snf1Δ mutant strain on media containing nonfermentable carbon sources. Furthermore, cells of the Tdsnf1Δ mutant were unable to proliferate under nonfermenting conditions. Finally, protein domain analysis showed that TdSnf1p contains a typical catalytic protein kinase domain (positions 41–293), which is also present in other Snf1p homologues. Within this region we identified a protein kinase ATP‐binding region (positions 48–71) and a consensus Ser/Thr protein kinase active site (positions 160–172). The GenBank Accession No. for the sequenced DNA fragment is HM131845. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of sulphur application on protein quality, fatty acid composition and nitrogen fixation of white lupin (Lupinus albus L.)

White lupin (Lupinus albus L.) is an important source of plant protein for both humans and livestock, due to high protein content, low alkaloids level, high level of unsaturated fatty acids, price and market availability in many countries. In this paper is reported the effect of S fertilization on white N fixation capability of lupin, grain yield and chemical characteristics in terms of protein fractions, fatty acid and mineral composition. Randomized complete block design with three replicates was used, and three S applications (0, 30 and 60 kg ha^?1, respectively) for white lupin were used. The S fertilization was split into two: 50 % before sowing and 50 % in the early of March as K₂SO₄. At the same time, both the legume and oat crops were fertilized uniformly with solution of 10 kg N ha^{?1 15}N NH₄ ¹⁵NO₃ (10 % ¹⁵N atomic excess). Data indicated that under Mediterranean environment on sub-alkaline soil, white lupin produces low grain and protein; however, S application increased plant yield and N fixation. In conclusion, it seems that S fertilization to white lupin should be recommended to soils with sub-optimal S levels to obtain maximum seed and protein yields. Moreover, S fertilization enhanced the protein quality increasing its degradable fraction, and improved the lupin oil quality through the increase in oleic and linolenic acids and the remarkable decrease in erucic acid.