Supplementation Of L-tryptophan Research Articles

Biosynthesis of Indigo Dyes and Their Application in Green Chemical and Visual Biosensing for Heavy Metals.

Fermentative production of natural colorants using microbial strains has emerged as a cost-effective and sustainable alternative to chemical synthesis. Visual pigments are used as signal outputs in colorimetric bacterial biosensors, a promising method for monitoring environmental pollutants. In this study, we engineered four self-sufficient indigo-forming enzymes, including HbpAv, bFMO, cFMO, and rFPMO, in a model bacterium E. coli. TrxA-bFMO was chosen for its strong ability to produce indigo under T7 lac and mer promoters' regulation. The choice of bacterial hosts, the supplementation of substrate l-tryptophan, and ventilation were crucial factors affecting indigo production. The indigo reporter validated the biosensors for Hg(II), Pb(II), As(III), and Cd(II). The biosensors reported Hg(II) as low as 14.1 nM, Pb(II) as low as 1.5 nM, and As(III) as low as 4.5 nM but increased to 25 μM for Cd(II). The detection ranges for Hg(II), Pb(II), As(III), and Cd(II) were quantified from 14.1 to 225 nM, 1.5 to 24.4 nM, 4.5 to 73.2 nM, and 25 to 200 μM, respectively. The sensitivity, responsive concentration range, and selectivity are comparable to β-galactosidase and luciferase reporter enzymes. This study suggests that engineered enzymes for indigo production have great potential for green chemical synthesis. Additionally, heterologous biosynthesis of indigo production can lead to the development of novel, low-cost, and mini-equipment bacterial biosensors with zero background noise for visual monitoring of pollutant heavy metals.

Gut Microbiota-Tryptophan Metabolism-GLP-1 Axis Participates in β-Cell Regeneration Induced by Dapagliflozin.

Sodium-glucose co-transporter 2 (SGLT2) inhibitor, an efficacious anti-diabetic agent, which has cardiovascular and renal benefits, can promote pancreatic β-cell regeneration in type 2 diabetic mice. However, the underlying mechanism remains unclear. In this study, we aimed to use multi-omics to identify the mediators involved in β-cell regeneration induced by dapagliflozin. We showed that dapagliflozin lowered blood glucose level, upregulated plasma insulin level, and increased islet area in db/db mice. Dapagliflozin reshaped gut microbiota, and modulated microbiotic and plasmatic metabolites related to tryptophan metabolism, especially L-tryptophan, in the diabetic mice. Notably, L-tryptophan upregulated the mRNA level of GLP-1 production-related genes (Gcg and Pcsk1) expression and promoted GLP-1 secretion in cultured mouse intestinal L-cells, and it increased supernatant insulin level in primary human islets, which was eliminated by GPR142 antagonist. Transplantation of fecal microbiota from dapagliflozin-treated mice, supplementation of L-tryptophan or treatment with dapagliflozin upregulated L-tryptophan, GLP-1, and insulin or C-peptide level, and promoted β-cell regeneration in db/db mice. Addition of exendin 9-39, a GLP-1 receptor (GLP-1R) antagonist, or pancreatic Glp1r knockout diminished these beneficial effects. In summary, treatment with dapagliflozin in type 2 diabetic mice promotes β-cell regeneration by upregulating GLP-1 production, which is mediated via gut microbiota and tryptophan metabolism.

Effects of Dietary L-TRP on Immunity, Antioxidant Capacity and Intestinal Microbiota of the Chinese Mitten Crab (Eriocheir Sinensis) in Pond Culture.

L-tryptophan (L-TRP) is an essential amino acid for the normal growth of crustaceans. As a nutritional supplement and antioxidant, L-TRP has the function of immune and antioxidant capacity regulation. From July to November, the effects of L-TRP on the immunity, antioxidant capacity and intestinal microflora of the Chinese mitten crab (Eriocheir sinensis) in pond culture were investigated. After feeding an L-TRP diet for 30 (named as August), 60 (named as September) and 106 (named as November) days, respectively, the activities of the immune and antioxidant enzymes in the hepatopancreas and hemolymph were evaluated, and the intestinal microbiota were profiled via high-throughput Illumina sequencing. The results showed that supplementation of L-TRP significantly increased the activities of AKP in the hepatopancreas in September, and significantly increased the activities of ACP in the hepatopancreas in August and September, and the hemolymph’s ACP activities also significantly increased in August and November (p < 0.05). Similarly, the activities of SOD, AOC and POD in the hepatopancreas significantly increased in September and November (p < 0.05) after feeding the L-TRP diet; meanwhile, the activities of SOD and AOC in the hemolymph also significantly increased in August (p < 0.05). However, in August, the L-TRP diet resulted in a significant increase in MDA activity in the hepatopancreas and hemolymph (p < 0.05). In addition, the results of the intestinal microbiota analysis showed that Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla in August, September and November, and Patescibacteria was the dominant phylum in September and November. After feeding the L-TRP diet, the richness of Cyanobacteria and Desulfobacterota significantly increased in August (p < 0.05), and the richness of Actinobacteriota significantly decreased in September (p < 0.05). Moreover, the L-TRP supplementation significantly reduced the abundance of ZOR0006 in the Firmicutes in September (p < 0.05). In conclusion, dietary L-TRP could improve the immunity and antioxidant ability and impact the intestinal health of E. sinensis at the early stage of pond culturing. However, long-term feeding of an L-TRP diet might have no positive impact on the activities of the immune, antioxidant enzymes and intestinal microbiota.

Effects of Dietary Supplementation of Acetate and L-Tryptophan Conjugated Bypass Amino Acid on Productivity of Pre- and Post-Partum Dairy Cows and Their Offspring.

Simple SummaryThis study examined the effect of acetate and L-tryptophan-conjugated bypass amino acid (ACT), supplemented (15 g/day) to Holstein cows during late pregnancy, on their productivity and the performance of offspring. We identified that the supplementation of ACT incorporated into diet was beneficial for improving the feed intake, blood hematology, and metabolites of the prepartum, and also had a positive effect on reducing saturated fatty acids in the colostrum of the cows postpartum and on the body weight of the newborn calves. The results of this study suggest that ACT supplementation improves the productivity of dairy cows.In this study, we investigated the effect of dietary supplementation with acetate and L-tryptophan-conjugated bypass amino acid (ACT) during late pregnancy on the production performance of cows pre- and postpartum and their offspring. Eight multiparous Holstein cows (calving date ±15 d, 2nd parity; n = 4) were supplied with diets without ACT supplementation (Control) or with 15 g/day ACT supplementation (ACT). The results showed that ACT improved the feed intake (FI) in dry cows. No differences in blood hematological parameters were found between the two groups of prepartum cows. The serum glutamic-oxaloacetic transaminase activity increased and the triglyceride concentration decreased in the ACT-treated group compared to the control group. In the postpartum cows, milk compositions were not affected by ACT supplementation. Saturated fatty acid (SFA) content in the colostrum was significantly lower in the ACT-treated group than in the control group. Serum glucose (GLC) level was significantly higher in the ACT-treated group than in the control group. Monocyte and GLC levels were lower in calves of groups where their dams had received ACT. Overall, we found higher FI in the dry cows, lower colostrum SFA levels, and heavier calf birth weight (5.5 kg) when the dams were supplemented with ACT, suggesting a positive nutrient compensation by ACT supplementation to dry cows.

Supplementation of l-tryptophan (an aromatic amino acid) in tris citric acid extender enhances post-thaw progressive motility, plasmalemma, mitochondrial membrane potential, acrosome, and DNA integrities, and in vivo fertility rate of buffalo (Bubalus bubalis) bull spermatozoa

The aromatic amino acid l-tryptophan is an essential and versatile molecule, acts by transferring an electron to free radicals and protects the plasma membrane from injuries. The aim of the present study was to investigate the effects of l-tryptophan in extender on semen quality parameters, in vitro longevity and in vivo fertility rate of buffalo spermatozoa during cryopreservation. Two ejaculates were collected from each bull (n = 2 ejaculates and n = 4 bulls) with artificial vagina at 42 °C followed by initial evaluation for volume, motility, concentrations and were diluted in five extenders (C = lacking l-tryptophan, D1 = 25 μ M l-tryptophan, D2 = 50 μ M l-tryptophan, D3 = 75 μ M l-tryptophan, and D4 = 100 μ M l-tryptophan) respectively, and cryopreserved. The experiment was repeated four times (n = 4 replicates). At post-dilution, sperm plasma membrane integrity (PMI, %), supravital plasma membrane integrity (SVPMI, %), hypo-resistivity (HR, %) and acrosome integrity (ACR-I, %) were significantly higher (P < 0.05) in extender supplemented with D4 than control. At post-thawing, progressive motility (PM, %), PMI, SVPMI, HR, ACR-I, and DNA-I of buffalo bull spermatozoa were significantly higher in D4 than control. Sperm in vitro longevity (%) assessed in terms of PM, SVPMI, and ACR-1 were significantly higher in D4 than control. Sperm mitochondrial membrane potential (%) was higher in treated groups than the control. The in vivo fertility rate was significantly higher in D4 than control (60.17% vs. 44.17%, P < 0.05). It is concluded that the supplementation of l-tryptophan in tris citric acid extender improves semen quality parameters, in vitro longevity and in vivo fertility rate of buffalo spermatozoa during freezing and thawing process.

L-tryptophan promotes the cheliped regeneration of Chinese mitten crab (Eriocheir sinensis) through melatonin, serotonin and dopamine involvement

It is particularly important to artificially promote limb regeneration of Eriocheir sinensis with high limb-impairment rate. This study was designed to evaluate the effects of dietary supplementation of L-tryptophan (L-trp) on cheliped regeneration. Through this study, we find that the dietary supplementation of 0.53% and 0.70% L-trp significantly increases limb regeneration rates over 14 d (P < .05). The expression of EcR-mRNA (ecdysteroid receptor) and Chi-mRNA (chitinase) are significantly upregulated with the dietary supplementation of 0.53% or 0.70% L-trp while the expression of MIH-mRNA (molt-inhibiting hormone) is significantly downregulated (P < .05). Moreover, digestive enzyme activities are significantly enhanced with dietary supplementation of 0.53% or 0.70% L-trp (P < .05). Further, dietary supplementation of L-trp significantly increases melatonin (MT) levels in eyestalks and L-trp levels in muscles of E. sinensis (P < .05). Interestingly, our study preliminarily explores the role of 5-HT and DA related receptors in the cheliped regeneration of E. sinensis. We find that dietary L-trp supplementation regulates the expression of 5-HT and DA-related receptors in digestive organs (hepatopancreas and intestines) and nervous tissues (cranial and thoracic ganglia), speculating that it may be involved in the improvement of digestion and absorption function and the regulation of nerve tissue repair during the cheliped regeneration of E. sinensis. Taken together, dietary supplementation of L-trp can promote limb regeneration by regulating regeneration-related gene expression and hepatopancreatic digestion in E. sinensis, which may be achieved by regulating MT levels and the binding of 5-HT and DA to corresponding receptors.

Dietary L-Tryptophan Modulates the Hematological Immune and Antibacterial Ability of the Chinese Mitten Crab, Eriocheir sinensis, Under Cheliped Autotomy Stress.

In pond cultures of juvenile Eriocheir sinensis, limb autotomy stress seriously affects and restricts the quality and economic benefits of aquaculture. This study was designed to evaluate the effects of dietary supplementation of L-tryptophan on E. sinensis under the cheliped autotomy stress. In the present study, 252 crabs were divided into four groups: dietary L-trp supplementation with 0.28, 0.40, 0.53, and 0.70%, and their hematological immunity, antioxidant capacity, anti-stress, and antibacterial ability were evaluated after 14 days of using biochemical analysis, flow cytometry, and molecular biology techniques. First, we counted the mortality after 14 days of feeding and found that compared with other treatments, dietary supplementation of 0.53 and 0.70% L-trp significantly lowered the mortality of E. sinensis. Moreover, the total hemocyte count (THC), hemocyanin, and glutathione (GSH) content, and glutathione peroxidase (GSH-Px) activity significantly increased at 7 and 14 d with dietary supplementation of 0.53 and 0.70% L-trp, in contrast with the significant decrease in malondialdehyde (MDA) content at 14 d in the same dietary groups (P<0.05). Next, the bacterial challenge test after 14 days of feeding showed that the THC levels, phagocytic rate, and acid phosphatase (ACP) and alkaline phosphatase (ALP) activity were significantly higher with dietary supplementation of 0.53 and 0.70% L-trp after 12 and 24 h of Aeromonas hydrophila injection, along with a significant improvement in the antioxidant capacity (P<0.05). Further, we measured the expression of antibacterial-related protein genes (EslecB and HSP 90) and found that they were significant up-regulated in the hepatopancreas, hemocytes, intestine, and gill in the groups with dietary supplementation of 0.53% and 0.70% L-trp after 12 h or 24 h of A. hydrophila injection (P<0.05). Taken together, the observations in this study indicate that dietary supplementation of L-trp can enhance the antioxidant capacity and improve the hematological immune status and antibacterial ability of E. sinensis under the cheliped autotomy stress, thereby increasing the survival rate of E. sinensis under cheliped autotomy stress.

Dietary supplementation of L-tryptophan: Effect on growth and survival of Pabda, Ompok bimaculatus (Bloch) fry

ABSTRACT A 30-day experiment was conducted to assess the effect of tryptophan-supplemented diets on growth and survival of Pabda, Ompok bimaculatus fry. Fifty pabda fry (0.114 ± 0.02 g; 2.45 ± 0.13 cm) were stocked into each aerated aquarium following a completely randomized design consisting of four treatments with triplicate each. Four iso-proteinious purified diets were prepared with different levels of tryptophan—0%, 1%, 2%, and 3%—of the dry diet and were designated as Control, TRP1, TRP2, and TRP3 respectively. Fishes were fed with the experimental diet ad libitum four times a day. The results showed that fish fed with tryptophan-supplemented diets exhibited significantly (P < 0.05) lower cannibalism and higher survival than the control diet. Further, the tryptophan-supplemented groups showed a significantly lower coefficient of variation (%) and size heterogeneity (P < 0.05). However, the growth as measured by body weight gain, length increment, and specific growth rate of fry in tryptophan-supplemented groups was significantly lower than the control group (P < 0.05). Moreover, maximum survival (52.67 ± 1.76%) and minimum cannibalism (21.33 ± 5.70%) coupled with higher growth and performance index (0.38 ± 0.01) were recorded in the 2% tryptophan-supplemented group compared to other tryptophan-fed groups. Overall interpretation from the present study concludes that the dietary supplementation of 2% tryptophan is recommended for better survival of pabda fish, although growth was compromised.

Development of a novel vector for cloning and expressing extremely toxic genes in Escherichia coli

Abstract Background Escherichia coli has been widely used as a host to clone and express heterologous genes. However, there are few vectors available for cloning and expressing extremely toxic genes, which limits further basic and applied research on extremely toxic proteins. Results In this study, a novel vector pAU10 was constructed in E. coli. pAU10 utilizes the combination of the efficient but highly repressible T7-lacO promoter/operator and the strong rrnBT2 transcriptional terminator upstream of the T7 promoter to strictly control unwanted transcription of the extremely toxic gene; in addition, the trp promoter/operator is oriented opposite to the T7 promoter to control the production of the antisense RNA that may block the translation of leaky mRNA. Without the supplementation of IPTG and L-tryptophan in the culture medium, transcription of the extremely toxic gene by the T7 promoter is highly repressed, and the trp promoter produces the antisense RNA, which strictly prevents unwanted expression of the extremely toxic protein in E. coli. With the supplementation of IPTG and L-tryptophan, the T7 promoter efficiently transcribes the extremely toxic gene, and the trp promoter does not produce the antisense RNA, ensuring efficient expression of the extremely toxic protein in E. coli. Tight regulation and efficiency of expression of an extremely toxic gene cloned in the vector pAU10 were confirmed by cloning and expressing the restriction endonuclease-encoding gene bamHI without its corresponding methylase gene in E. coli JM109(DE3). Conclusion pAU10 is a good vector used for cloning and expressing extremely toxic genes in E. coli.

Long-term tryptophan supplementation decreased the welfare and innate immune status of pikeperch juveniles

It has been demonstrated that short-term supplementation of L-tryptophan (TRP) can mitigate the primary neuroendocrine response to stress in some fish species, but such stress reduction was reported to be both doseand context-dependent (Basic et al, 2013; Machado et al, 2015). So, the TRP responses may be species related or depend on the stress levels experienced by the fish. Since percid fish were reported to be more stress responsiveness than common aquaculture species such as rainbow trout (Jentoft et al, 2005), this study aimed (1) to determine to what extent a long-term dietary TRP mitigate the physiological response of pikeperch (Sander lucioperca) to emersion stress, and (2) to characterize the related immune status. Pikeperch juveniles of 10 g received four experimental diets: (CT) = control groups without any stress and any feed TRP supplement, (CTs) = control groups submitted to emersion stress but without any feed TRP supplement, 3TRPs = groups receiving 3-time TRP diet and submitted to emersion stress, 6TRPs = groups receiving 6-time TRP diet and submitted to emersion stress. Various organs were sampled on D7, D37 and D91 of TRP supplementation for evaluation of physiological and immune responses; samplings were done one hour after the emersion challenge stress. Specific growth rate (SGR) as well as food conversion rate (FCR) were also checked. Emersion stress induced a significant increase in plasma cortisol both after a single stress or repeated stress challenges. Dietary TRP significantly decreased cortisol levels in a dose related manner both after a single or repeated stress; but plasma glucose level was only affected after a single stress but not after long-term feeding. The two stress indicators measured showed that pikeperch displayed higher stress responsiveness as already demonstrated for European perch in comparison to salmonids (Jentoft et al, 2005). The reduction in physiological stress status by dietary TRP was associated to a significant decrease in plasma lysosomal activity, especially on D91; indicating negative interaction with the innate immune pathways. Growth rate was slowed by the longterm dietary TRP in association to an increase in FCR values. The available results indicate that long-term TRP supplementation has negative impact on the overall welfare status of pikeperch. Other analyses are ongoing and more results concerning keybrain neurotransmitters such as serotonin, dopamine and their metabolites concentrations as well as on the expressions of key-immune genes (C3-1, TNF-α, IL-1β, etc) will be discussed.

Effects of short term supplementation of l-tryptophan and reducing large neutral amino acid along with l-tryptophan supplementation on growth and stress response in pigs

Abstract Two experiments were conducted to evaluate the effects of short term dietary supplementation of l -Trp and reducing large neutral amino acid (LNAA; valine, leucine, isoleucine, tyrosine, and phenylalanine) on growth and stress response in nursery and growing pigs. In Exp. 1, 674 crossbred pigs in 40 pens at 9-week of age were randomly allotted to 2 dietary treatments with supplementation of 0.0% and 0.8% l -Trp to a corn and soybean meal basal diet. Experimental period was composed of 5 days in a nursery and 7 days in a finisher. After 12 days feeding of experimental diets, pigs were provided a common diet for an additional 7 days. In Exp. 2, 108 crossbred barrows at 6-week of age were randomly allotted to 3 dietary treatments: (1) a corn soybean meal basal diet (4.5% LNAA) supplemented with 0.0% l -Trp; (2) a corn soybean meal basal diet (4.5% LNAA) supplemented with 0.8% l -Trp; (3) a reduced LNAA (3.8%) diet supplemented with 0.7% l -Trp, which had the same Trp:LNAA ratio as treatment 2. The experimental period lasted 16 days. In Exp. 1, during the entire period, pigs fed the diet supplemented with 0.8% l -Trp had increased ADG and gain:feed (P l -Trp supplementation. On day 6, one day after mixing, pigs fed the diet supplemented with 0.8% l -Trp had a lower (P l -Trp supplementation. In Exp. 2, during the entire period, pigs fed the diet supplemented with 0.8% l -Trp or a reduced LNAA diet supplemented with 0.7% l -Trp had increased gain:feed (P l -Trp supplementation. Weight gain and gain:feed were similar (P > 0.05) between pigs fed the diet supplemented with 0.8% l -Trp and pigs fed a reduced LNAA diet supplemented with 0.7% l -Trp. In conclusion, short term supplementation of 0.8% l -Trp improved growth performance of pigs during period of social-mixing and was associated with reduced stress hormone concentrations. Dietary supplementation of 0.8% l -Trp had similar effects on feed efficiency as a reduced LNAA diet supplemented with 0.7% l -Trp, suggesting lowering LNAA is a valid method of reducing levels of l -Trp supplementation required for mitigating stress response.

Effect of dietary supplementation of l-tryptophan on thermal tolerance and oxygen consumption rate in Cirrhinus mrigala fingerlings under varied stocking density

A 60 day feeding trial was conducted to study the effect of dietary l-tryptophan on thermal tolerance and oxygen consumption rate of freshwater fish, mrigala, Cirrhinus mrigala reared under ambient temperature at low and high stocking density. Four hundred eighty fingerlings were distributed into eight experimental groups. Four groups each of low density group (10 fishes/75L water) and higher density group (30 fishes/75L water) were fed a diet containing 0, 0.68, 1.36 or 2.72% l-tryptophan in the diet, thus forming eight experimental groups namely, Low density control (LC) (basal feed +0% l-tryptophan); LT1 (basal feed+0.68% l-tryptophan); LT2 (basal feed+1.36% l-tryptophan); LT3 (basal feed+2.72% l-tryptophan); high density control (HC) (basal feed+0% l-tryptophan); HT1 (basal feed+0.68% l-tryptophan); HT2 (basal feed+1.36% l-tryptophan); and HT3 (basal feed+2.72% l-tryptophan) were fed at 3% of the body weight. The test diets having crude protein 34.33±0.23 to 35.81±0.18% and lipid 423.49±1.76 to 425.85±0.31KCal/100g were prepared using purified ingredients. The possible role of dietary l-tryptophan on thermal tolerance and oxygen consumption rate was assessed in terms of critical thermal maxima (CTMax), critical thermal minima (CTMin), lethal thermal maxima (LTMax) and lethal thermal minima (LTMin). The CTMax, CTMin, LTMax and LTMin values were found to be significantly higher (p<0.05) in the treatment groups with CTMax 42.94±0.037 (LT2); LT Max 43.18±0.070 (LT2); CTMin 10.47±0.088 (LT2) and LTMin 9.42±0.062 (LT3), whereas the control group showed a lower tolerance level. The same trend was observed in the high density group (CTMax 42.09±0.066 (LT3); LTMax 43 23±0.067 (HT3); CTMin 10.98±0.040 (HT3) and LTMin 9.74±0.037 (HT3). However, gradual supplementation of dietary l-tryptophan in the diet significantly reduced the oxygen consumption rate in both the low density group (Y=−26.74x+222.4, r²=0.915) and the high density group (Y=−32.96x+296.5, r²=0.8923). Dietary supplementation of l-tryptophan at a level of 1.36% improved the thermal tolerance level and reduced the oxygen consumption rate in C. mrigala fingerlings.

Aeromonas punctata PNS-1: a promising candidate to change the root morphogenesis of Arabidopsis thaliana in MS and sand system

A model system of sand, comprising Arabidopsis plants inoculated with Aeromonas punctata PNS-1 strain, was used to evaluate the bacterial effect in modulation of plant root structure at second-order lateral root level. In MS media, the root morphogenesis was changed only at first-order lateral root level when inoculated with PNS-1 strain. Inoculation with PNS-1 strain was subjected to significant (P < 0.01) increase in primary root length and lateral root density in both MS and sand system. However, this strain modulated the root structure in the sand environment in a complex manner that may be helpful for incitation of the plant–microbe interaction close to natural environment. In order to determine whether this change in root morphology was due to bacterial auxin, Arabidopsis transgenic line (DR5:GUS) was used to reveal the change in homeostasis of endogenous auxin. In PNS-1 inoculated transgenic seedlings of Arabidopsis plant (DR5:GUS), endogenous auxin in primary root apices and lateral roots was enhanced. For confirmation, PNS-1 was evaluated for auxin production in vitro, showed an increase in auxin production after supplementation of l-tryptophan. The presence of ACC deaminase activity in PNS-1 showed its possible involvement in primary root elongation. In the present study Aeromonas punctata PNS-1 is the potential candidate for triggering the change in root morphogenesis of Arabidopsis thaliana with the involvement of auxin and ACC deaminase production.

Activation of Indoleamine 2,3-Dioxygenase in Patients with Scrub Typhus and Its Role in Growth Restriction of Orientia tsutsugamushi

BackgroundOur earlier genome-wide expression study revealed up-regulation of a tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase (IDO1), in patients with scrub typhus. This gene has been previously reported to have anti-microbial activity in a variety of infectious diseases; therefore, we aimed to prove whether it is also involved in host defense against Orientia tsutsugamushi (OT) infection.Methodology/Principal FindingsUsing LC-MS, we observed an increased ratio of serum L-kynurenine to serum L-tryptophan in patients with scrub typhus, which suggests an active catalytic function of this enzyme upon the illness. To evaluate the effect of IDO1 activation on OT infection, a human macrophage-like cell line THP-1 was used as a study model. Although transcription of IDO1 was induced by OT infection, its functional activity was not significantly enhanced unless the cells were pretreated with IFN-γ, a potent inducer of IDO1. When the degree of infection was evaluated by quantitative real-time PCR, the relative number of OT 47 kDa gene per host genes, or infection index, was markedly reduced by IFN-γ treatment as compared to the untreated cultures at five days post-infection. Inhibition of IDO1 activity in IFN-γ treated cultures by 1-methyl-L-tryptophan, a competitive inhibitor of IDO1, resulted in partial restoration of infection index; while excessive supplementation of L-tryptophan in IFN-γ treated cultures raised the index to an even higher level than that of the untreated ones. Altogether, these data implied that IDO1 was partly involved in restriction of OT growth caused by IFN-γ through deprivation of tryptophan.Conclusions/SignificanceActivation of IDO1 appeared to be a defensive mechanism downstream of IFN-γ that limited intracellular expansion of OT via tryptophan depletion. Our work provided not only the first link of in vivo activation of IDO1 and IFN-γ-mediated protection against OT infection but also highlighted the promise of this multifaceted gene in scrub typhus research.

L-Tryptophan Supplementation Can Decrease Fatigue Perception During an Aerobic Exercise with Supramaximal Intercalated Anaerobic Bouts in Young Healthy Men

ABSTRACTPhysical exercise is often terminated not due to muscle fatigue but because of inadequate neural drive in the serotonergic system. Modifications in activity levels of the serotonergic system, induced by variations in the availability of L-tryptophan (a serotonin precursor) may alter neural drive. We examined the effect of L-tryptophan supplementation on physical performance by combining aerobic work with brief periods of supramaximal intensity that closely mimics the activity typical of team sports. Twenty healthy young sportsmen (mean age 21.2 ± 0.7 years) performed a submaximal exercise on a cycle ergometer, with a workload corresponding to 50% of their respective VO2 max for 10 min, followed by a maximal intensity exercise for 30 s. This sequence was repeated three times and, after the fourth series, each participant continued to exercise at the highest speed that he could sustain for 20 min. This protocol was performed twice: once with and finally without supplementation of L-tryptophan, in random order and double-blind. Peak power output, average anaerobic power output, and power output during the last 20 min of the trial were higher on the trials performed with L-tryptophan supplementation than on those performed with placebo. The distance covered during the last 20 min of the trial was 11,959 ± 1,753 m on placebo and 12,526 ± 1,617 m on L-tryptophan (p < .05). In conclusion, in some types of exercises, modification of the serotonergic system may improve the physical performance.

Effect of magnesium sulphate and l-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothane positive — nn-, n = 36; and homozygous halothane negative — NN-, n = 33) were fed with a supplementation of magnesium sulphate (Mg) and/or l-tryptophan (Trp) in the diet for 5 days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1 h on rough roads). Individual feed intake was recorded during the 5-d treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO 2. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2 kg/day was significantly different among diets ( P < 0.05; Control: 8.7%; Mg&Trp: 43.5%; Trp: 17.4%) and they were considered to have inadequate supplement intake. During the ante mortem period, 15.2% of pigs included in the experiment died, and this percentage decreased to 8.7% in those pigs with a feed intake > 2 kg/day, all of them from the stress-sensitive pigs (nn). In general, no differences were observed in the behaviour of pigs along the corridor leading to the stunning system and inside the CO 2 stunning system. During the stunning procedure, Trp diet showed shorter periods of muscular excitation than control and Mg&Trp diets. The combination of a stressful ante mortem treatment and Mg&Trp supplementation led to carcasses with high incidence of severe skin lesions. Different meat quality results were found when considering all pigs or considering only those with adequate supplement intake. In this later case, Trp increased pH 45 (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle ( P < 0.05) and pH at 24 h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and exudative (DFD) traits in SM muscle ( P < 0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0% of the SM muscles from nn pigs were classified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits ( P < 0.0001). No significant differences were found between genotypes on the incidence of DFD meat. Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended.

Dietary supplementation of l-tryptophan mitigates crowding stress and augments the growth in Cirrhinus mrigala fingerlings

A 60 days feeding trial was conducted to study the stress mitigation and hence growth augmenting effect of dietary l-tryptophan during high density group stress in Cirrhinus mrigala fingerlings. Four hundred eighty fingerlings were distributed into eight experimental groups. Each group either of low density group (10 fishes/75 L water) or higher density group (30 fishes/75 L water) was fed with a diet containing either 0, 0.68, 1.36 or 2.72% l-tryptophan in the diet, thus eight experimental groups viz. low density control (LC) (basal feed + 0% l-tryptophan); LT1 (basalfeed + 0.68% l-tryptophan); LT2 (basalfeed + 1.36% l-tryptophan); LT3 (basalfeed + 2.72% l-tryptophan) high density control (HC) (basal feed + 0% l-tryptophan); HT1 (basalfeed + 0.68% l-tryptophan); HT2 (basalfeed + 1.36% l-tryptophan); and HT3 (basalfeed + 2.72% l-tryptophan) were fed at 3% of the body weight with isonitrogenous (34.33 ± 0.23 to 35.81 ± 0.18 CP%) and isocaloric (423.49 ± 1.76 to 425.85 ± 0.31 K.Cal/100 g) purified diets. The possible role of dietary l-tryptophan on stress mitigation was assessed in terms of blood glucose, plasma cortisol, lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alanine amino transferase (ALT), aspartate amino transferase (AST), acetyl choline esterase (AChE) assays, whereas growth was evaluated in terms of weight gain %, specific growth (SGR) and protein efficiency ratio (PER). The LDH, MDH, ALT, AST activities were found to be significantly higher ( p < 0.05) in the control groups and decreasing trend of LDH, MDH, ALT and AST activities were observed with the increasing level of dietary l-tryptophan. However, high density group exhibited significantly higher value ( p < 0.05) for the above parameters than their low density counterpart at similar level of l-tryptophan in the diet. In contrast to above parameters, AChE activity exhibited a reverse trend. In both the stocking densities, l-tryptophan supplemented groups found to have higher ( p < 0.05) growth, SGR and PER. The Plasma cortisol level was found to be significantly higher in the high density group than its low density counterpart. However, gradual supplementation of l-tryptophan in diet significantly reduced the cortisol level both in high density ( Y = − 26.33 x + 219.53, r 2 = 0.95) and low density group ( Y = − 27.57 x + 169.28, r 2 = 0.92). Similar trend was also found in blood glucose. Hence, dietary supplementation of l-tryptophan at a minimum level of 1.36% concomitantly reduced the stress in C. mrigala fingerlings. Though 2.72% dietary tryptophan also reduces the stress but 1.36% level appears to be cost effective.

Porcine choroid plexus epithelial cells induce Streptococcus suis bacteriostasis in vitro.

The involvement of the choroid plexus in host defense during bacterial meningitis is unclear. Aiming to elucidate possible antibacterial mechanisms, we stimulated primary porcine choroid plexus epithelial cells (pCPEC) with proinflammatory cytokines and challenged them with various Streptococcus suis strains. In the supernatant of gamma interferon (IFN-gamma)-stimulated pCPEC, streptococcal growth was markedly suppressed. Costimulation with tumor necrosis factor alpha enhanced this bacteriostatic effect, while supplementation of L-tryptophan completely eliminated it. We also demonstrate that an activation of indoleamine 2,3-dioxygenase in the pCPEC seems to be responsible for the IFN-gamma-induced bacteriostasis. This supports the hypothesis of an active role of the choroid plexus in host defense against bacterial meningitis.

Interferon-gamma-induced activation of indoleamine 2,3-dioxygenase in cord blood monocyte-derived macrophages inhibits the growth of group B streptococci.

Neonatal sepsis is most often caused by group B streptococci (GBS) and is a major cause of death in the neonatal period. The response of the immune system in the newborn child has received much attention and is thought to be deficient in a number of ways. The effector response of neonatal monocyte-derived macrophages (MDM) was investigated. Interferon-gamma induced the activation of indoleamine 2,3-dioxygenase in MDM and inhibited the growth of GBS. Both effects were enhanced by the addition of tumor necrosis factor-alpha to the culture conditions. The coincident supplementation of L-tryptophan with the bacteria abrogated the bacterial growth inhibition, thus confirming the causative role of L-tryptophan depletion. Control of the extracellular as well as intracellular L-tryptophan levels may thus be one of the effector mechanisms with which the immune system defends the host against GBS dissemination and disease.

310 Modulation of GABA c receptors by extracellular Ca 2+. kaort aokt

A 60 days feeding trial was conducted to study the stress mitigation and hence growth augmenting effect of dietary l-tryptophan during high density group stress in Cirrhinus mrigala fingerlings. Four hundred eighty fingerlings were distributed into eight experimental groups. Each group either of low density group (10 fishes/75 L water) or higher density group (30 fishes/75 L water) was fed with a diet containing either 0, 0.68, 1.36 or 2.72% l-tryptophan in the diet, thus eight experimental groups viz. low density control (LC) (basal feed + 0%l-tryptophan); LT1 (basalfeed + 0.68% l-tryptophan); LT2 (basalfeed + 1.36% l-tryptophan); LT3 (basalfeed + 2.72% l-tryptophan) high density control (HC) (basal feed + 0%l-tryptophan); HT1 (basalfeed + 0.68% l-tryptophan); HT2 (basalfeed + 1.36% l-tryptophan); and HT3 (basalfeed + 2.72% l-tryptophan) were fed at 3% of the body weight with isonitrogenous (34.33 ± 0.23 to 35.81 ± 0.18 CP%) and isocaloric (423.49 ± 1.76 to 425.85 ± 0.31 K.Cal/100 g) purified diets. The possible role of dietary l-tryptophan on stress mitigation was assessed in terms of blood glucose, plasma cortisol, lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alanine amino transferase (ALT), aspartate amino transferase (AST), acetyl choline esterase (AChE) assays, whereas growth was evaluated in terms of weight gain %, specific growth (SGR) and protein efficiency ratio (PER). The LDH, MDH, ALT, AST activities were found to be significantly higher (p < 0.05) in the control groups and decreasing trend of LDH, MDH, ALT and AST activities were observed with the increasing level of dietary l-tryptophan. However, high density group exhibited significantly higher value (p < 0.05) for the above parameters than their low density counterpart at similar level of l-tryptophan in the diet. In contrast to above parameters, AChE activity exhibited a reverse trend. In both the stocking densities, l-tryptophan supplemented groups found to have higher (p < 0.05) growth, SGR and PER. The Plasma cortisol level was found to be significantly higher in the high density group than its low density counterpart. However, gradual supplementation of l-tryptophan in diet significantly reduced the cortisol level both in high density (Y = − 26.33x + 219.53, r2 = 0.95) and low density group (Y = − 27.57x + 169.28, r2 = 0.92). Similar trend was also found in blood glucose. Hence, dietary supplementation of l-tryptophan at a minimum level of 1.36% concomitantly reduced the stress in C. mrigala fingerlings. Though 2.72% dietary tryptophan also reduces the stress but 1.36% level appears to be cost effective.