Concentrations Of Spermidine Research Articles

Polyamine synthesis from arginine and proline in tissues of developing chickens.

Polyamines (putrescine, spermidine, and spermine) are synthesized primarily from ornithine via ornithine decarboxylase (ODC) in mammals. Although avian tissues contain ODC activity, little is known about intracellular sources of ornithine for their polyamine synthesis. This study tested the hypothesis that arginase and proline oxidase contribute to polyamine synthesis in chickens. Kidney, jejunum, leg muscle, and liver from 0-, 7-, 14- and 21-day-old broiler chickens were assayed for the activities of arginase, proline oxidase (POX), ornithine aminotransferase (OAT), and ornithine decarboxylase (ODC). Kidney slices were also used to determine 14C-polyamine synthesis from [U-14C]arginine and [U-14C]proline. Furthermore, these tissues and plasma were analyzed for polyamines. Results indicate that all tissues contained OAT (mitochondrial) and ODC (cytosolic) activities, but arginase and POX activities were only detected in the mitochondria of chicken kidneys. Renal POX and arginase activities were greater at 7days of age compared to newly hatched birds, and declined by Day 14. Renal arginase activity was greater at 21 days compared to 14days of age, but there was no change in renal POX activity during that same period. Concentrations of polyamines in the kidneys and plasma were greater on Day 7 compared to Day 0 and decreased thereafter on Days 14 and 21. Kidney slices readily converted arginine and proline into polyamines, with peak rates being on Day 7. Concentrations of putrescine, spermidine and spermine in the plasma of chickens were about 20- to 100-fold greater than those in mammals. Our results indicate that polyamines are synthesized from arginine and proline in avian kidneys. Unlike mammals, polyamines released from the kidneys are likely the major source of polyamines in the blood and other extra-renal tissues in chickens.

Contents of Polyamines and Biogenic Amines in Canned Pet (Dogs and Cats) Food on the Austrian Market.

Biogenic amines accumulate in proteinaceous raw materials used for pet food production. In canned, sterilized food, amine levels of the ingredients are preserved and may both be indicative of hygiene deficiencies in the ingredients as well as for potential adverse effects to the animals feeding on it. We determined the contents of biogenic amines and polyamines (dansyl derivatives, high performance liquid chromatography) in a variety of canned food for dogs (n = 72) and cats (n = 114) on the Austrian market and compared the results with common quality indices. Contents of putrescine, cadaverine, and tyramine were below the limit of detection in >70% of samples (maximum values: 21.5, 98.4 and 32.5 mg/kg wet weight, respectively). Median contents of histamine, spermidine, and spermine were 14.5, 12.7, and 29.4 mg/kg, and maximum values were 61.6, 28.2, and 53.6 mg/kg wet weight, respectively. The sum of (putrescine + cadaverine + histamine + tyramine) was >50 mg/kg in 22.6% of samples. The biogenic amine index exceeded “1” in 26.7% of samples. Whilst cat food contained significantly higher amounts of tyramine, dog food contained significantly higher amounts of histamine and spermine. In canned cat food, the ingredient “fish” was identified as a statistically significant risk factor for a biogenic amine index > 1 (relative risk = 3.0 (95% confidence interval: 1.8–5.5)) and for (putrescine + cadaverine + histamine + tyramine) exceeding 50 mg/kg (relative risk = 2.4 (95% confidence interval: 1.2–4.6)), due to higher contents of cadaverine in food samples containing fish. While all samples met the limits suggested in pet food production, we could demonstrate that the inclusion of fish in the formulation bears a significant risk for higher cadaverine contents.

Genotype and Maturity Stage Affect the Content and Composition of Polyamines in Tomato—Possible Relations to Plant and Human Health

Polyamines (PAs) are molecules affecting several physiological characteristics in all living organisms with cell protective effects, thereby impacting plant and human health. Here, we used HPLC-DAD-ESI-MS to evaluate the content and composition of PAs in eight tomato genotypes over their maturation period, and related the content and composition to other quality traits and possible implications for plant and human health. The tomato genotype, maturity stage and their interactions, significantly affected the content and composition of PAs. Two of the genotypes, ‘Huichol’ and ‘Rio Grande’ showed consistently lower levels of PAs than the other evaluated genotypes. The variation in content and composition of PAs among genotypes was found to vary inconsistently over the maturation period. Putrescine content in the different genotypes either did not vary significantly, increased, or showed the lowest level in the middle of the maturation period, while spermidine content decreased or did not show significant variation. The genotypes ‘HT36’ and ‘HT25’ showed high levels of PAs during red and green maturity stages, respectively, and can thereby be seen as suitable health promoting red and green candidate tomatoes. Depiction of variation of the PAs creates opportunities for breeding and production of health promoting tomato as a food or food additive.

High urine concentration of spermidine predicts and associates with in-hospital acute kidney injury after cardiac surgery

Background and Aims: Acute Kidney Injury (AKI) affects up to 30% of the patients undergoing cardiac surgery and it is related with high morbidity and mortality. Research has been performed for an early post-surgery prediction, usually within the first 6h. However, this can be too late so we aim to investigate molecular features able to predict in-hospital AKI even before cardiac surgery.

Exogenous Nitric Oxide Confers Tolerance to Cr(VI) in Maize (Zea mays L.) Seedlings by Modulating Endogenous Oxido-Nitrosative Events

The use of exogenous compounds such as ‘gasotransmitter’ molecules is a well-established agronomic strategy to improve the crop tolerance to environmental stresses. In this current work, when Cr (200 µM) was combined with the nitric oxide (NO) generator sodium nitroprusside SNP, 500 µM) there was a suppression of metal-induced alterations in embryo growth. Exogenous NO produced by SNP reduced the accumulation of toxic hydrogen peroxide and methylglyoxal and stress-linked proline in Cr-treated seedlings. Chromium increased thiol and S-nitrosothiol levels but this was restored to control levels by SNP, in spite of a competing NO reaction leading to increase of S-nitrosoglutathione content. However, added complexity was indicated by addition of arginine analogue N (ω)-nitro-L-arginine methyl ester (L-NAME, 500 µM) in the germinating medium to suppress endogenous NO production. This suppressed endogenous NO production but superoxide dismutase (SOD) was suppressed not enhanced in Cr + L-NAME treatments. In addition, Cr + L-NAME significantly decreased the content of spermidine and spermine in epicotyls as compared to Cr treatment alone. Similarly, exposure to Cr + SNP decreased spermidine and spermine levels in both radicles and epicotyls. This is important as polyamines have been suggested as route for NO production. Thus, our observations suggest that exogenous NO mitigates Cr-induced damage and confers seedling tolerance to Cr through suppression of NADPH oxidase activity and increased GSNO contents. This may act to prevent an excess of methylglyoxal and hydrogen peroxide. However, the reduction in polyamine mediated cellular NO generation could also promote increased viability under Cr stress.

Overexpression of the white clover TrSAMDC1 gene enhanced salt and drought resistance in Arabidopsis thaliana

S-adenosylmethionine decarboxylase (SAMDC) mediates the biosynthesis of polyamines (PAs) and plays a positive role in plants’ response to adversity stress tolerance. In this study, we isolated a SAMDC gene from white clover, which is located in mitochondria. It was strongly induced when white clover exposed to drought (15% PEG6000), salinity (200 mM NaCl), 20 μM spermidine, 100 μM abscisic acid, and 10 mM H2O2, especially in leaves. The INVSc1 yeast introduced with TrSAMDC1 had tolerance to drought, salt, and oxidative stress. Overexpression of TrSAMDC1 in Arabidopsis showed higher fresh weight and dry weight under drought and salt treatment and without growth inhibition under normal conditions. Leaf senescence induced by drought and saline was further delayed in transgenic plants, regardless of cultivation in 1/2 MS medium and soil. During drought and salt stress, transgenic plants exhibited a significant increase in relative water content, maximum photosynthesis efficiency (Fv/Fm), performance index on the absorption basis (PIABS), activities of antioxidant protective enzymes such as SOD, POD, CAT, and APX, and a significant decrease in accumulation of MDA and H2O2 as compared to the WT. The concentrations of total PAs, putrescine, spermidine, and spermidine in transgenic lines were higher in transgenic plants than in WT under normal and drought conditions. These results suggested that TrSAMDC1 could effectively mitigate abiotic stresses without the expense of production and be a potential candidate gene for improving the drought and salt resistance of crops.

Characterising the Response of Human Breast Cancer Cells to Polyamine Modulation.

Breast cancer is a complex heterogeneous disease with multiple underlying causes. The polyamines putrescine, spermidine, and spermine are polycationic molecules essential for cell proliferation. Their biosynthesis is upregulated in breast cancer and they contribute to disease progression. While elevated polyamines are linked to breast cancer cell proliferation, there is little evidence to suggest breast cancer cells of different hormone receptor status are equally dependent on polyamines. In this study, we characterized the responses of two breast cancer cells, ER+ (oestrogen receptor positive) MCF-7 and ER- MDA-MB-231 cell lines, to polyamine modulation and determined the requirement of each polyamine for cancer cell growth. The cells were exposed to DFMO (a polyamine pathway inhibitor) at various concentrations under different conditions, after which several growth parameters were determined. Exposure of both cell lines to DFMO induced differential growth responses, MCF-7 cells showed greater sensitivity to polyamine pathway inhibition at various DFMO concentrations than the MDA-MB-231 cells. Analysis of intracellular DFMO after withdrawal from growth medium showed residual DFMO in the cells with concomitant decreases in polyamine content, ODC protein level, and cell growth. Addition of exogenous polyamines reversed the cell growth inhibition, and this growth recovery appears to be partly dependent on the spermidine content of the cell. Similarly, DFMO exposure inhibits the global translation state of the cells, with spermidine addition reversing the inhibition of translation in the breast cancer cells. Taken together, these data suggest that breast cancer cells are differentially sensitive to the antitumour effects of polyamine depletion, thus, targeting polyamine metabolism might be therapeutically beneficial in breast cancer management based on their subtype.

Salt-tolerance of Phaseolus vulgaris L. is a function of the potentiation extent of antioxidant enzymes and the expression profiles of polyamine encoding genes

Selection and improvement of crop salt tolerance constitutes an urgent need for increasing agricultural and food production to feed the growing human population. Two bean (Phaseolus vulgaris L.) genotypes, namely Tema and Djadida varying in their tolerance to NaCl, were selected to investigate the determinant physiological and molecular mechanisms underlying salt tolerance. At the physiological level, salinity resulted in a significant decrease in growth, water status, stomatal conductance and photosynthesis for both genotypes. The potassium content was higher in the salt-tolerant genotype Tema under normal and saline conditions. Both genotypes had a significant increase in proline, glucose, fructose and sucrose concentrations, but glucose and fructose were differentially higher in the salt-tolerant genotype. While putrescine and spermidine concentrations decreased, spermine concentration significantly enhanced under salt stress along with antioxidant enzymes activities namely catalase, glutathione reductase and ascorbate peroxidase. The increase was higher in the salt-tolerant genotype. The expression levels of genes encoding enzymes involved in spermine biosynthesis revealed an upregulation of spermine synthase (SPMS) and a downregulation of polyamine oxidase (PAO4). Overall, the difference between genotypes is more quantitative than qualitative; the salt-tolerant genotype Tema displayed a better physiological and molecular response under salinity. By measuring these molecules in salt-stressed plants, several genotypes could be screened for breeding programmes leading to improve salt tolerance in beans.

Potential Use of Vacuum Impregnation and High-Pressure Homogenization to Obtain Functional Products from Lulo Fruit (Solanum quitoense Lam.).

Lulo (Solanum quitoense Lam.) is a Colombian fruit that is mostly used in the preparation of homemade juice as well as natural remedy for hypertension. The aim of this study was to determine physicochemical and antioxidant properties (antioxidant capacity, total phenols, flavonoids and spermidine content, and polyphenolic compounds profile by liquid chromatography—mass spectrometry (LC-MS)) of the lulo fruit and its juice. Additionally, vacuum impregnation (VI) properties of the fruit and the effect of high homogenization pressure (50, 100, and 150 MPa) on the juice properties were studied. The results revealed a good availability and impregnation capacity of the pores in fruits with similar maturity index. The main differences observed between the juice and fruit derive from removing solids and bioactive components in the filtering operation. However, the effect of high-pressure homogenization (HPH) on particle size and bioactive compounds increases the antiradical capacity of the juice and the diversity in polyphenolics when increasing the homogenization pressure.

Survey of biogenic amines (histamine and spermidine) in commercial seafood by enzyme linked immunosorbent assay (ELISA)

Introduction Worldwide there is serious concern about food and consumer safety [1], namely with seafood products. Consequently, there is a major concern regarding food spoilage which make them unsuitable for human consumption. When deteriorating, seafood products suffers a complex series of events that begins when the organism die [1,2]. Therefore, there is a strong need for developing reliable seafood quality analysis. In the present study we surveyed histamine and spermidine in several seafood products (fresh fish and clams), purchased in a Portuguese traditional market. Materials and methods Fresh seafood (Sardina pilchardus, Trachurus trachurus, Sparus aurata and Ruditapes decussata) were purchased in a market and taken to the laboratory in refrigerated containers. A total of 10 specimens were sampled from each species. Then samples were processed for analysis by homogenising in a phosphate buffer saline solution, centrifuged (10,000×g at 4 °C) for 15 min) and then stored at –80 °C until analysis. Seafood samples were assessed for the presence and content of histamine and spermidine using an indirect Enzyme Linked Immunosorbent assay (ELISA) [3]. The statistical analysis was performed using the Mann–Whitney U-test to determine differences between biogenic amine levels in seafood samples. Statistics was performed with a significance level of 5%, using the software Statistica 8.0 (Statsoft, Tulsa, OK, USA). Results The results show variable results between species (from < LD to 184104 mg histamine/Kg wet weight). The highest levels were detected in T. trachurus samples and the lowest in clams. However, it was possible to detect the presence of the selected biogenic amines (histamine and spermidine) in most samples analysed. The lowest levels of spermidine were determined in R. decussata (1504.43 mg/kg w.w.), while the highest levels were determined in T. trachurus (184104 mg/Kg w.w.). Regarding histamine, the lowest levels were determined in R. decussata 20.23 mg/Kg w.w.) and the highest levels were measured in T. trachurus (460.25 mg/kg w.w.). Discussion and conclusions Although we are capable to detect the presence of the selected biogenic amines, in most of the samples the levels were below the limits established by Food and Drug Administration [4] and the European Union Commission Regulation (EC) No 1441/2007 [5].

Cadmium-resistant and arginine decarboxylase-producing endophytic Sphingomonas sp. C40 decreases cadmium accumulation in host rice (Oryza sativa Cliangyou 513)

In this study, an cadmium (Cd)-immobilizing and arginine decarboxylase-producing endophytic Sphingomonas sp. strain C40 obtained from the seeds of Oryza sativa Cliangyou 513 was characterized for its Cd availability and Cd uptake in host rice using hydroponic and soil experiments. The Cd concentration decreased by 51–95% compared to the control, while the spermidine concentration increased by 19–25% with Cd compared with no Cd in the strain C40-inoculated solution. Strain C40 decreased the above-ground tissue Cd content by 27–37% and increased spermine and spermidine contents by 28–67% and the expression levels of genes involved in spermine and spermidine production by 29–217% in rice roots compared to the controls. Furthermore, correlation analyses showed the significantly negative correlation between rice root spermine and spermidine contents and above-ground tissue Cd content. In the Cd-added soil, strain C40 promoted the rice biomass by 29–36% and decreased rice root, above-ground tissue, and grain Cd contents by 18, 16, and 33% and total grain Cd uptake by 14% compared with the controls at the maturity stage. Strain C40 decreased the exchangeable Cd content by 27% and increased the Fe and Mn oxides-bound Cd content by 45% in the rice rhizosphere soils at the maturity stage compared with the controls. These results suggested that the endophytic bacterial strain C40 increased rice root polyamine production and their related gene expression and the transformation of available Cd to unavailable Cd, leading to reduced Cd accumulation and translocation from the rice roots to grains.

Effects of adding live Saccharomyces cerevisiae and Aspergillus-based enzyme extracts on ruminal fermentation, plasma polyamine concentrations, and fiber digestibility in beef steers fed a high-forage diet

We evaluated the effects of adding live Saccharomyces cerevisiae (SC) and Aspergillus -based extract (ABE) on rumen fermentation, plasma polyamine concentrations, and in vitro fiber digestibility in beef steers fed mixed red clover–orchardgrass hay. Eight rumen-cannulated Angus crossbred beef steers were assigned to 4 treatments arranged in a replicated 4 × 4 Latin square design with four 21-d periods. Dietary treatments were (1) control (CON; basal diet without additive), (2) SC (CON + 15 g/d of live SC), (3) ABE (5 g of ABE), and (4) SC+ABE (15 g/d of live SC + 5 g of ABE). On d 21, blood samples were collected before morning feeding for plasma metabolome analysis (including polyamines such as spermines, spermidine, and putrescine). Rumen fluid samples were collected 3, 6, and 9 h after feeding for analysis of VFA, ammonia-N concentrations, and in vitro DM and NDF digestibility. Compared with CON, neither SC nor ABE had effects ( P > 0.10) on rumen fermentation and in vitro digestibility. In contrast, SC+ABE increased ( P ≤ 0.05) the ruminal concentrations of acetate, butyrate, and total VFA and in vitro DM and NDF digestibilities. Both SC and SC+ABE increased ( P < 0.05) plasma concentrations of spermidine, spermine, and kynurenine. Supplementation of SC with or without ABE to forage-fed beef steers increased plasma concentrations of polyamines and kynurenine, a possible indication of improved immune function; however, combining SC and ABE, but not SC alone, improved the rumen fermentation and in vitro fiber digestibility.

Exogenous spermidine affects polyamine metabolism in the mouse hypothalamus.

Spermidine is important for the hypothalamic control of pituitary secretion of hormones involved in neuroendocrine functions in mammals. In this study, the effect of exogenous spermidine on the expression of genes and proteins related to polyamine metabolism and polyamine levels was examined. The results indicated that treatment with spermidine at 0.05 mg/g (BW) significantly increased the levels of Oaz1 mRNA and protein expression and decreased putrescine content in mouse hypothalamus (p < 0.05). The administration with spermidine at 0.10 mg/g significantly increased the levels of Oaz1, Oaz2, and Odc expression in mouse hypothalamus (p < 0.05). Treatment with spermidine at 0.05 mg/g significantly increased the levels of Ssat mRNA expression and reduced the level of Smo mRNA expression in mouse hypothalamus (p < 0.05). Putrescine concentrations in the hypothalamus after the administration of spermidine at 0.10 and 0.15 mg/g were significantly higher than those in the control group (p < 0.05). The concentration of both spermidine and spermine in the hypothalamus after the administration of spermidine at 0.15 mg/g was decreased significantly (p < 0.05). In summary, our results indicate that exogenous spermidine affects polyamine homeostasis in the mouse hypothalamus by modulating the expression of genes and proteins related to polyamine metabolism.

Peanut (Arachis hypogaea L.) S-adenosylmethionine decarboxylase confers transgenic tobacco with elevated tolerance to salt stress.

Polyamines play an important role in stress response. In the pathway of polyamines synthesis, S-adenosylmethionine decarboxylase (SAMDC) is one of the key enzymes. In this study, a full length cDNA of SAMDC (AhSAMDC) was isolated from peanut (Arachis hypogaea L.). Phylogenetic analysis revealed high sequence similarity between AhSAMDC and SAMDC from other plants. In peanut seedlings exposed to sodium chloride (NaCl), the transcript level of AhSAMDC in roots was the highest at 24 h that decreased sharply at 72 and 96 h after 150 mM NaCl treatment. However, the expression of AhSAMDC in peanut leaves was significantly inhibited, and the transcript levels in leaves were not different compared with control These results implied the tissue-specific and time-specific expression of AhSAMDC. The physiological effects and functional mechanism of AhSAMDC were further evaluated by overexpressing AhSAMDC in tobaccos. The transgenic tobacco lines exhibited higher germination rate and longer root length under salt stress. Reduced membrane damage, higher antioxidant enzyme activity, and higher proline content were also observed in the transgenic tobacco seedlings. What's more, AhSAMDC also led to higher contents of spermidine and spermine, which can help to scavenge reactive oxygen species. Together, this study suggests that AhSAMDC enhances plant resistance to salt stress by improving polyamine content and alleviating membrane damage.

Exogenous Salicylic Acid Modulates the Response to Combined Salinity-Temperature Stress in Pepper Plants (Capsicum annuum L. var. Tamarin).

Growers in the cultivated areas where the climate change threatens the agricultural productivity and livelihoods are aware that the current constraints for good quality water are being worsened by heatwaves. We studied the combination of salinity (60 mM NaCl) and heat shock stress (43 °C) in pepper plants (Capsicum annuum L. var. Tamarin) since this can affect physiological and biochemical processes distinctly when compared to separate effects. Moreover, the exogenous application of 0.5 mM salicylic acid (SA) was studied to determine its impacts and the SA-mediated processes that confer tolerance of the combined or stand-alone stresses. Plant growth, leaf Cl− and NO3− concentrations, carbohydrates, and polyamines were analyzed. Our results show that both salinity stress (SS) and heat stress (HS) reduced plant fresh weight, and SA only increased it for HS, with no effect for the combined stress (CS). While SA increased the concentration of Cl− for SS or CS, it had no effect on NO3−. The carbohydrates concentrations were, in general, increased by HS, and were decreased by CS, and for glucose and fructose, by SA. Additionally, when CS was imposed, SA significantly increased the spermine and spermidine concentrations. Thus, SA did not always alleviate the CS and the plant response to CS cannot be directly attributed to the full or partial sum of the individual responses to each stress.

PSVI-13 Effects of Saccharomyces cerevisiae and Aspergillus-based enzyme extracts on rumen fermentation, fiber digestibility, and plasma metabolome of beef steers fed red clover/orchard hay

Abstract Saccharomyces cerevisiae (SC) and Aspergillus-based enzyme extracts (ABE) are respectively fed to improve gut health and forage digestibility in ruminants. Also, cells of SC contain polyamines which can regulate the immune function. This study evaluated the synergistic effects of SC and ABE on rumen fermentation, plasma polyamine concentrations, and in vitro fiber digestibility of beef steers fed red clover/orchard hay. Eight rumen-cannulated Holstein steers were assigned to 4 treatments arranged in a 4 × 4 Latin square design with four 21-d periods. Dietary treatments were (1) CON (basal diet without additive), (2) SC (CON + 15 g/d of live SC; PMI, Arden Hills, MN, (3) ABE (5 g of ABE; PMI, Arden Hills, MN, USA) and (4) SC+ABE (15 g/d of live SC + 5 g of ABE). On d 21, blood samples were collected before morning feeding for analysis of plasma polyamines (spermines, spermidine, and putrescine). Rumen fluid samples were collected 3, 6, and 9 hours after feeding for analysis of VFA and in vitro dry matter and fiber digestibility. The model included the effects of treatment, period, and random effects of cow and square. Compared with CON, neither SC nor ABE had effects (P &amp;gt; 0.10) on ruminal VFA profile. In contrast, SC+ABE increased (P ≤ 0.05) the ruminal concentrations of acetate, butyrate, valerate and total VFA concentrations. In vitro dry matter and fiber digestibilities were increased (P &amp;lt; 0.05) by SC+ABE, but not by SC or ABE alone. Both SC and SC+ABE increased (P &amp;lt; 0.05) plasma concentrations of spermidine and spermine. These results suggest that SC supplementation with or without ABE increased plasma concentrations of polyamines; however, SC and ABE synergistically improved the rumen fermentation and in vitro fiber and DM digestibility.

The positive effect of spermidine in older adults suffering from dementia : First results of a3-month trial.

SummaryThe worldwide prevalence of dementia is estimated at 35.6 million and will rise to 115 million by 2050. There is therefore an urgent need for well-founded dementia diagnostics and well-researched therapeutic options. Previous studies have highlighted that spermidine has the ability to trigger the important process of dissolving amyloid-beta plaques by autophagy. They also confirmed that nutritional intervention with the natural polyamine spermidine can prevent memory loss in aging model organisms. This multicentric double-blind preliminary study focused on the effect of oral spermidine supplementation on older adults’ cognitive performance. Memory tests were carried out on 85 subjects aged between 60 and 96 years in 6 nursing homes in Styria. Blood samples were taken for the determination of spermidine concentration and measurement of metabolic parameters. The results demonstrated a clear correlation between the intake of spermidine and the improvement in cognitive performance in subjects with mild and moderate dementia in the group treated with the higher spermidine dosage. The most substantial improvement in test performance was found in the group of subjects with mild dementia with an increase of 2.23 points (p = 0.026) in the mini mental state examination (MMSE) and 1.99 (p = 0.47) in phonematic fluidity. By comparison, the group which had a lower spermidine intake showed consistent or declining cognitive performance.

Evaluating the Engineered Saccharomyces cerevisiae With High Spermidine Contents for Increased Tolerance to Lactic, Succinic, and Malic Acids and Increased Xylose Fermentation

Saccharomyces cerevisiae is a promising candidate for production of organic acids as it is more tolerant to these acids than the prokaryotes. However, the large-scale production of organic acids from lignocellulosic biomass is limited by their accumulation in the growth medium and inability of xylose fermentation by S. cerevisiae. Here we showed that high intracellular spermidine (SPD) contents confers enhanced tolerance to lactic, succinic, and malic acids in S. cerevisiae. Specifically, in the presence of 20 g/L malic acid, the maximum specific growth rate and dry cell weight of a S. cerevisiae with two fold higher SPD content were 40% and 36% higher than those of the control strain. When a xylose assimilation pathway was introduced into an engineered strain with high SPD content, the resulting S. cerevisiae strain exhibited 23∼47% higher xylose consumption rate and 6∼16% higher ethanol productivity than those of the control strain during the four times of repeated-batch fermentations using a mixture of glucose and xylose as carbon sources. These results suggest that the strain developed in this study would serve as a platform strain for production of organic acids.

Stage-specific protein regulation during somatic embryo development of Carica papaya L. ‘Golden’

Somatic embryogenesis is an important biotechnological technique for large-scale propagation of elite genotypes. Identifying stage-specific compounds associated with somatic embryo development can help elucidate the ontogenesis of Carica papaya L. somatic embryos and improve tissue culture protocols. To identify the stage-specific proteins that are present during the differentiation of C. papaya somatic embryos, proteomic analyses of embryos at the globular, heart, torpedo and cotyledonary developmental stages were performed. Mass spectrometry data have been deposited in the ProteomeXchange with the dataset identifier PXD021107. Comparative proteomic analyses revealed a total of 801 proteins, with 392 classified as differentially accumulated proteins in at least one of the developmental stages. The globular-staged presented a higher number of unique proteins (16), and 7 were isoforms of 60S ribosomal proteins, suggesting high translational activity at the beginning of somatic embryogenesis. Proteins related to mitochondrial metabolism accumulated to a high degree at the early developmental stages and then decreased with increasing development, and they contributed to cell homeostasis in early somatic embryos. A progressive increase in the accumulation of vicilin, late embryogenesis abundant proteins and chloroplastic proteins that lead to somatic embryo maturation was also observed. The differential accumulation of acetylornithine deacetylase and S-adenosylmethionine synthase 2 proteins was correlated with increases in putrescine and spermidine contents, which suggests that both polyamines should be tested to determine whether they increase the conversion rates of globular- to cotyledonary-staged somatic embryos. Taken together, the results showed that somatic embryo development in C. papaya is regulated by the differential accumulation of proteins, with ribosomal and mitochondrial proteins more abundant during the early somatic embryo stages and seed maturation proteins more abundant during the late stages.

Spermidine is not an independent factor regulating limb muscle mass in mice following androgen deprivation.

Maintaining a critical amount of skeletal muscle mass is linked to reduced morbidity and mortality. In males, testicular androgens regulate muscle mass with a loss of androgens being critical as it is associated with muscle atrophy. Atrophy of the limb muscles is particularly important, but the pathways by which androgens regulate limb muscle mass remain equivocal. We used microarray analysis to identify changes to genes involved with polyamine metabolism in the tibialis anterior (TA) muscle of castrated mice. Of the polyamines, the concentration of spermidine (SPD) was significantly reduced in the TA of castrated mice. To assess whether SPD was an independent factor by which androgens regulate limb muscle mass, we treated castrated mice with SPD for 8 weeks and compared them with sham operated mice. Though this treatment paradigm effectively restored SPD concentrations in the TA muscles of castrated mice, mass of the limb muscles (i.e., TA, gastrocnemius, plantaris, and soleus) were not increased to the levels observed in sham animals. Consistent with those findings, muscle force production was also not increased by SPD treatment. Overall, these data demonstrate for the first time that SPD is not an independent factor by which androgens regulate limb skeletal muscle mass. Novelty: Polyamines regulate growth in various cells/tissues. Spermidine concentrations are reduced in the limb skeletal muscle following androgen depletion. Restoring spermidine concentrations in the limb skeletal muscle does not increase limb muscle mass or force production.