scholarly journals Impacts of a newly identified behaviour-altering trematode on its host amphipod: from the level of gene expression to population

Parasitology ◽  
2015 ◽  
Vol 142 (12) ◽  
pp. 1469-1480 ◽  
Author(s):  
YASMIN GULER ◽  
STEPHEN SHORT ◽  
AMAIA GREEN ETXABE ◽  
CHRISTOPHER M. SHERHOD ◽  
PETER KILLE ◽  
...  
Keyword(s):  
Serotonin Receptor ◽  
Tryptophan Hydroxylase ◽  
Parasite Prevalence ◽  
Body Cavity ◽  
The Body ◽  
Trematode Species ◽  
Acid Decarboxylase ◽  
Altered Expression ◽  
Amino Acid Decarboxylase ◽  
Transcriptomic Level

SUMMARYChanges to host behaviour induced by some trematode species, as a means of increased trophic transmission, represents one of the seminal examples of host manipulation by a parasite. The amphipodEchinogammarus marinus (Leach, 1815) is infected with a previously undescribed parasite, with infected individuals displaying positive phototaxic and negative geotaxic behaviour. This study reveals that the unknown parasite encysts in the brain, nerve cord and the body cavity ofE. marinus, and belongs to the Microphallidae family. An 18 month population study revealed that host abundance significantly and negatively correlated with parasite prevalence. Investigation of the trematode's influence at the transcriptomic level revealed genes with putative neurological functions, such as serotonin receptor 1A, an inebriated-like neurotransmitter, tryptophan hydroxylase and amino acid decarboxylase, present consistent altered expression in infected animals. Therefore, this study provides one of the first transcriptomic insights into the neuronal gene pathways altered in amphipods infected with a trematode parasite associated with changes to its host's behaviour and population structure.

scholarly journals The occurrence of Contracaecum sp. larvae (Nematoda : Anisakidae) in the catfishClarias gariepinus (Burchell) from Lake Chivero, Zimbabwe

2004 ◽  
Vol 71 (1) ◽  
Author(s):  
M. Barson
Keyword(s):  
Significant Relationship ◽  
Condition Factor ◽  
Clarias Gariepinus ◽  
Parasite Prevalence ◽  
Body Cavity ◽  
The Body ◽  
Nematode Parasites ◽  
Significant Difference ◽  
Third Stage ◽  
Males And Females

Clarias gariepinus were collected from Lake Chivero, Zimbabwe, and examined for nematode parasites from November 2000 to May 2002. Of the 202 specimens collected, 42.6 % were infected with third-stage larvae of Contracaecum sp. in the body cavity. The intensity of the infection was 1-7 worms per fish (mean intensity = 2.2). Seasonal variation in the prevalence of the parasite was not obvious and there was no significant difference in the prevalence of infection between males and females (c2 = 2.228; P > 0.05). No significant relationship between host size and prevalence was established. There was also no significant relationship between intensity and the body condition factor (r = 0.11; P > 0.05). The low parasite prevalence may have been caused by the disruption of the infection cycle since piscivorous birds, which are the final hosts of the parasite, do not feed on C. gariepinus in Lake Chivero.

scholarly journals Structural basis for the histamine synthesis by human histidine decarboxylase

2014 ◽  
Vol 70 (a1) ◽  
pp. C458-C458
Author(s):  
Hirofumi Komori ◽  
Yoko Nitta ◽  
Hiroshi Ueno ◽  
Yoshiki Higuchi
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Histidine Decarboxylase ◽  
The Body ◽  
Structural Basis ◽  
Acid Decarboxylase ◽  
Amino Acid Decarboxylase ◽  
Histamine Production ◽  
Novel Drugs ◽  
High Sequence Homology

Histamine is a bioactive amine responsible for a variety of physiological reactions, including allergy, gastric acid secretion, and neurotransmission. In mammals, histamine production from histidine is catalyzed by histidine decarboxylase (HDC). Mammalian HDC is a pyridoxal 5'-phosphate (PLP)-dependent decarboxylase and belongs to the same family as mammalian glutamate decarboxylase (GAD) and mammalian aromatic L-amino acid decarboxylase (AroDC). The decarboxylases of this family function as homodimers and catalyze the formation of physiologically important amines like GABA and dopamine via decarboxylation of glutamate and DOPA, respectively. Despite high sequence homology, both AroDC and HDC react with different substrates. For example, AroDC catalyzes the decarboxylation of several aromatic L-amino acids, but has little activity on histidine. Although such differences are known, the substrate specificity of HDC has not been extensively studied because of the low levels of HDC in the body and the instability of recombinant HDC, even in a well-purified form. However, knowledge about the substrate specificity and decarboxylation mechanism of HDC is valuable from the viewpoint of drug development, as it could help lead to designing of novel drugs to prevent histamine biosynthesis. We have determined the crystal structure of human HDC in complex with inhibitors, histidine methyl ester (HME) and alpha-fluoromethyl histidine (FMH). These structures showed the detailed features of the PLP-inhibitor adduct (external aldimine) in the active site of HDC. These data provided insight into the molecular basis for substrate recognition among the PLP-dependent L-amino acid decarboxylases.

Gastrointestinal immunity against tryptophan hydroxylase-1, aromatic L-amino-acid decarboxylase, AIE-75, villin and Paneth cells in APECED

2015 ◽  
Vol 158 (2) ◽  
pp. 212-220 ◽  
Author(s):  
Nicolas Kluger ◽  
Martta Jokinen ◽  
Anu Lintulahti ◽  
Kai Krohn ◽  
Annamari Ranki
Keyword(s):  
Amino Acid ◽  
Tryptophan Hydroxylase ◽  
Paneth Cells ◽  
Acid Decarboxylase ◽  
Amino Acid Decarboxylase

scholarly journals Synthesis, transport, and metabolism of serotonin formed from exogenously applied 5-HTP after spinal cord injury in rats

2014 ◽  
Vol 111 (1) ◽  
pp. 145-163 ◽  
Author(s):  
Yaqing Li ◽  
Lisa Li ◽  
Marilee J. Stephens ◽  
Dwight Zenner ◽  
Katherine C. Murray ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Brain Stem ◽  
Tryptophan Hydroxylase ◽  
Acid Decarboxylase ◽  
Amino Acid Decarboxylase ◽  
Cord Injury ◽  
Motoneuron Activity

Spinal cord transection leads to elimination of brain stem-derived monoamine fibers that normally synthesize most of the monoamines in the spinal cord, including serotonin (5-hydroxytryptamine, 5-HT) synthesized from tryptophan by enzymes tryptophan hydroxylase (TPH, synthesizing 5-hydroxytryptophan, 5-HTP) and aromatic l-amino acid decarboxylase (AADC, synthesizing 5-HT from 5-HTP). Here we examine whether spinal cord caudal to transection remains able to manufacture and metabolize 5-HT. Immunolabeling for AADC reveals that, while most AADC is confined to brain stem-derived monoamine fibers in spinal cords from normal rats, caudal to transection AADC is primarily found in blood vessel endothelial cells and pericytes as well as a novel group of neurons (NeuN positive and GFAP negative), all of which strongly upregulate AADC with injury. However, immunolabeling for 5-HT reveals that there is no detectable endogenous 5-HT synthesis in any structure in the spinal cord caudal to a chronic transection, including in AADC-containing vessels and neurons, consistent with a lack of TPH. In contrast, when we applied exogenous 5-HTP (in vitro or in vivo), AADC-containing vessels and neurons synthesized 5-HT, which contributed to increased motoneuron activity and muscle spasms (long-lasting reflexes, LLRs), by acting on 5-HT2receptors (SB206553 sensitive) located on motoneurons (TTX resistant). Blocking monoamine oxidase (MAO) markedly increased the sensitivity of the motoneurons (LLR) to 5-HTP, more than it increased the sensitivity of motoneurons to 5-HT, suggesting that 5-HT synthesized from AADC is largely metabolized in AADC-containing neurons and vessels. In summary, after spinal cord injury AADC is upregulated in vessels, pericytes, and neurons but does not endogenously produce 5-HT, whereas when exogenous 5-HTP is provided AADC does produce functional amounts of 5-HT, some of which is able to escape metabolism by MAO, diffuse out of these AADC-containing cells, and ultimately act on 5-HT receptors on motoneurons.

scholarly journals Autoantibodies to human tryptophan hydroxylase and aromatic L-amino acid decarboxylase

2004 ◽  
pp. 313-321 ◽  
Author(s):  
C Dal Pra ◽  
S Chen ◽  
C Betterle ◽  
R Zanchetta ◽  
V McGrath ◽  
...  
Keyword(s):  
Amino Acid ◽  
Autoimmune Diseases ◽  
Coeliac Disease ◽  
Tryptophan Hydroxylase ◽  
Acid Decarboxylase ◽  
Type I ◽  
Type Ii ◽  
Autoimmune Thyroid ◽  
Amino Acid Decarboxylase

OBJECTIVE: To assess the prevalence of autoantibodies (Abs) to tryptophan hydroxylase (TPH) and aromatic l-amino acid decarboxylase (AADC) in patients with different autoimmune diseases and to analyse their respective epitopes. DESIGN: TPH and AADC Abs were measured in an immunoprecipitation assay using (35)S-labelled full-length and fragments of TPH and AADC. METHODS: Patients with different autoimmune adrenal diseases (n=84), non-adrenal autoimmune diseases (n=37), idiopathic vitiligo (n=8) and 56 healthy blood donors were studied. RESULTS: Fourteen of twenty-three (61%) of patients with autoimmune polyglandular syndrome (APS) type I and 1/34 (3%) of patients with isolated Addison's disease (AD) were positive for TPH Abs. None of the patients with APS type II (n=27), coeliac disease (n=10), autoimmune thyroid disease (AITD) (n=11), type 1 diabetes mellitus (DM) (n=16) or idiopathic vitiligo (n=8) was positive for TPH Abs. AADC Abs were detected in 12/23 (52%) patients with APS type I, in 1/29 (3%) patients with APS type II and 1/34 (3%) patients with isolated AD. None of the patients with coeliac disease, type 1 DM, AITD or idiopathic vitiligo was positive for AADC Abs. TPH Abs were found to interact with the C-terminal amino acids (aa) 308-423, central aa 164-205 and N-terminal aa 1-105 of the TPH molecule. AADC Ab binding epitopes were within the C-terminal aa 382-483, the central aa 243-381 and the N-terminal aa 1-167. CONCLUSIONS: Our study suggests that TPH Abs and AADC Abs react with several different epitopes and that different epitopes are recognized by different sera. The prevalence of TPH Abs and AADC Abs in patients with APS type I in our study is in agreement with previous reports. TPH Abs and AADC Abs were found very rarely in patients with other forms of autoimmune adrenal disease and were not detected in patients with non-adrenal autoimmune diseases.

scholarly journals [11C]5-HTP and microPET are Not Suitable for Pharmacodynamic Studies in the Rodent Brain

2013 ◽  
Vol 34 (1) ◽  
pp. 118-125 ◽  
Author(s):  
Anniek KD Visser ◽  
Nisha K Ramakrishnan ◽  
Antoon TM Willemsen ◽  
Valentina Di Gialleonardo ◽  
Erik FJ de Vries ◽  
...  
Keyword(s):  
Tryptophan Hydroxylase ◽  
Compartment Model ◽  
Study Groups ◽  
Male Rats ◽  
Acid Decarboxylase ◽  
Model Parameters ◽  
Amino Acid Decarboxylase ◽  
Arterial Blood ◽  
Pet Tracer ◽  
Patlak Analysis

The PET tracer [11C]5-hydroxytryptophan ([11C]5-HTP), which is converted to [11C]5-hydroxytryptamine ([11C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [11C]5-HTP in rat? Male rats were scanned with [11C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [11C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [11C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [11C]5-HTP to [11C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [11C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.

scholarly journals Is sleep bruxism related to the levels of enzymes involved in the serotonin synthesis pathway?

2021 ◽  
Author(s):  
Joanna Smardz ◽  
Helena Martynowicz ◽  
Anna Wojakowska ◽  
Joanna Wezgowiec ◽  
Cyprian Olchowy ◽  
...  
Keyword(s):  
Tryptophan Hydroxylase ◽  
Serum Levels ◽  
Significant Negative Correlation ◽  
Sleep Bruxism ◽  
Acid Decarboxylase ◽  
Exploratory Research ◽  
Serotonin Synthesis ◽  
Amino Acid Decarboxylase ◽  
Single Night ◽  
Medical University

Abstract Objectives This exploratory research aimed to evaluate the levels of tryptophan hydroxylase 1 (TPH1) and aromatic l-amino acid decarboxylase (DDC), which play an important role in the serotonin synthesis pathway, in individuals with sleep bruxism (SB) diagnosed using audio–video polysomnography (vPSG) and compare them with that of individuals not presenting with SB. Materials and methods The study included adult patients hospitalized in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. The participants underwent a single-night vPSG for the evaluation of the SB parameters. Peripheral blood samples were also collected from them for estimating the serum levels of TPH1 and DDC. Results A total of 105 patients (80 women and 25 men) were included in the study. All the patients were Caucasians and aged 18–63 years (mean age: 33.43 ± 10.8 years). Seventy-five patients (71.43%) presented with SB, of which 50 (47.62%) had severe SB, while the remaining 30 patients (28.57%) did not. No statistically significant differences in TPH1 and DDC levels were observed between the individuals with SB and without SB. A significant negative correlation was found between tonic SB episodes and DDC levels (p = 0.0012). Other correlations between the SB parameters and the levels of the studied enzymes were statistically insignificant (p > 0.05 for all comparisons). Conclusions The levels of the enzymes that are crucial for serotonin synthesis (TPH1 and DDC) did not seem to influence SB. Clinical relevance This study provides important insights for further research on the relationship between the serotonin pathway and SB, which should take into account not only the process of serotonin synthesis but also the effect of serotonin-dependent neurotransmission on SB.

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