Optimal levels of the essential amino acids histidine, lysine and threonine in Caenorhabditis elegans maintenance medium

Nematology ◽  
2008 ◽  
Vol 10 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Nancy Lu ◽  
Xiaoyan Xiong

AbstractCurrent Caenorhabditis elegans Maintenance Medium (C-CeMM) is used to cultivate the free-living nematode, C. elegans. In C-CeMM, ten amino acids (AA) were found to be nutritionally essential. The optimal requirements of seven of these ten essential AA were determined previously. The objectives of the present study were to determine the optimal requirements of the remaining three essential AA: histidine, lysine and threonine. The Optimal Caenorhabditis elegans Maintenance Medium (O-CeMM) was formulated using the levels of all essential AA that supported the optimal population growth for C. elegans from previous quantitative studies and from the results obtained in the first part of this study. The efficacy of O-CeMM, C-CeMM, as well as Egg CeMM (E-CeMM), based on the essential AA ratio in hen's egg, was studied. The optimal requirements (mg ml–1) of histidine, lysine and threonine were determined to be 2.26 (8× C-CeMM), 1.03-2.06 (1× to 2× C-CeMM), and 0.717-2.86 (1× to 4× C-CeMM), respectively. It was found that O-CeMM supported a significantly higher (1.55 ∼ 1.60×) population growth (number of nematodes/ml) when compared with C-CeMM and E-CeMM. For both O-CeMM and C-CeMM, the AA efficiency ratio (AAER; g dry weight (wt) gain of C. elegans/g of total AA) was determined to be 0.18, which was significantly higher than the 0.15 that was determined in E-CeMM. Although the O-CeMM supported a significantly higher population growth, a higher level of histidine and consequently higher total AA were used in O-CeMM than in C-CeMM. Therefore, based on the findings on AAER, it was concluded that both the O-CeMM and C-CeMM were equally efficient for the cultivation of C. elegans.

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 314-320 ◽  
Author(s):  
Veeren M Chauhan ◽  
David I Pritchard

AbstractCaenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.


2020 ◽  
Vol 21 (21) ◽  
pp. 7813
Author(s):  
Kiho Lee ◽  
Iliana Escobar ◽  
Yeeun Jang ◽  
Wooseong Kim ◽  
Frederick M. Ausubel ◽  
...  

Sphingosine-1-phophate (S1P) is a sphingolipid-derived signaling molecule that controls diverse cellular functions including cell growth, homeostasis, and stress responses. In a variety of metazoans, cytosolic S1P is transported into the extracellular space where it activates S1P receptors in a concentration-dependent manner. In the free-living nematode Caenorhabditis elegans, the spin-2 gene, which encodes a S1P transporter, is activated during Gram-positive or Gram-negative bacterial infection of the intestine. However, the role during infection of spin-2 and three additional genes in the C. elegans genome encoding other putative S1P transporters has not been elucidated. Here, we report an evolutionally conserved function for S1P and a non-canonical role for S1P transporters in the C. elegans immune response to bacterial pathogens. We found that mutations in the sphingosine kinase gene (sphk-1) or in the S1P transporter genes spin-2 or spin-3 decreased nematode survival after infection with Pseudomonas aeruginosa or Enterococcus faecalis. In contrast to spin-2 and spin-3, mutating spin-1 leads to an increase in resistance to P. aeruginosa. Consistent with these results, when wild-type C. elegans were supplemented with extracellular S1P, we found an increase in their lifespan when challenged with P. aeruginosa and E. faecalis. In comparison, spin-2 and spin-3 mutations suppressed the ability of S1P to rescue the worms from pathogen-mediated killing, whereas the spin-1 mutation had no effect on the immune-enhancing activity of S1P. S1P demonstrated no antimicrobial activity toward P. aeruginosa and Escherichia coli and only minimal activity against E. faecalis MMH594 (40 µM). These data suggest that spin-2 and spin-3, on the one hand, and spin-1, on the other hand, transport S1P across cellular membranes in opposite directions. Finally, the immune modulatory effect of S1P was diminished in C. eleganssek-1 and pmk-1 mutants, suggesting that the immunomodulatory effects of S1P are mediated by the p38 MAPK signaling pathway.


Author(s):  
Zhenming Chi ◽  
Kuiran Yan ◽  
Lingmei Gao ◽  
Jing Li ◽  
Xianghong Wang ◽  
...  

A total of 327 yeast strains from seawater, sediments, mud of salterns, guts of the marine fish and marine algae were obtained. After crude protein of the yeasts was estimated by the method of Kjehldahl, we found that eight strains of the marine yeasts grown in the medium with 20 g l−1 glucose contained more than 30.4 g protein per 100 g of cell dry weight. The results of routine identification and molecular methods show that they belong to Metschnikowa reukaui, Cryptococcus aureus, Aureobasidium pullulan, Yarrowia lipolytica and Hanseniaspora uvarum, respectively. With the exception of Aureobasidium pullulans 4#2 with nucleic acid of 7.7% (w/w), all other yeast strains contained less than 5.0% (w/w) of nucleic acid. Analysis of fatty acids shows that all the yeast strains tested had a large amount of C18:0 and C18:1 fatty acids while analysis of amino acids indicates that the yeast strains tested had a large amount of essential amino acids, especially lysine and leucine which are very important nutritive components for marine animals.


2014 ◽  
Vol 60 (1) ◽  
Author(s):  
Romina E. D’Almeida ◽  
María R. Alberto ◽  
Phillip Morgan ◽  
Margaret Sedensky ◽  
María I. Isla

AbstractZuccagnia punctata Cav. (Fabaceae), commonly called jarilla macho or pus-pus, is being used in traditional medicine as an antiseptic, anti-inflammatory and to relieve muscle and bone pain. The aim of this work was to study the anthelmintic effects of three structurally related flavonoids present in aerial parts of Z. punctata Cav. The biological activity of the flavonoids 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2´,4´-dihydroxychalcone (DHC) was examined in the free-living nematode Caenorhabditis elegans. Our results showed that among the assayed flavonoids, only DHC showed an anthelmintic effect and alteration of egg hatching and larval development processes in C. elegans. DHC was able to kill 50% of adult nematodes at a concentration of 17 μg/mL. The effect on larval development was observed after 48 h in the presence of 25 and 50 μg/mL DHC, where 33.4 and 73.4% of nematodes remained in the L3 stage or younger. New therapeutic drugs with good efficacy against drug-resistant nematodes are urgently needed. Therefore, DHC, a natural compound present in Z. punctata, is proposed as a potential anthelmintic drug.


Nematology ◽  
2005 ◽  
Vol 7 (5) ◽  
pp. 761-766 ◽  
Author(s):  
Nancy Lu ◽  
Rekha Balachandar

AbstractCaenorhabditis elegans is a free-living nematode cultured in an axenic medium, the Caenorhabditis elegans Maintenance Medium (CeMM), which contains B-vitamins, salts, amino acids, nucleic acid substituents, growth factors and glucose as an energy source. After initial experiments established that either pantothenate or pantethine would satisfy the vitamin B5 requirement in C. elegans, reproduction in the nematodes was measured in eight equimolar concentrations of calcium pantothenate, pantethine or coenzyme A. The optimal levels for pantothenate were found to be 7.5, 30 and 120 μg ml−1. The optimal levels for pantethine and coenzyme A were found to be 35 μg ml−1 and 100 μg ml−1, respectively. Among the three compounds, coenzyme A (at 100 μg/ml) supported a significantly greater population growth and, perhaps, is a more metabolically active form. Mild toxicity was demonstrated for pantothenate at 480μg ml−1, pantethine at 560 and 140 μg ml−1, and coenzyme A was found to exhibit toxicity at 410 and 1700 μg ml−1. Based on our results, we recommend that in the future the CeMM could be supplemented with pantothenate (7.5 μg ml−1) alone.


1991 ◽  
Vol 115 (5) ◽  
pp. 1237-1247 ◽  
Author(s):  
R M Hemmer ◽  
S G Donkin ◽  
K J Chin ◽  
D G Grenache ◽  
H Bhatt ◽  
...  

Mouse mAb M38 was used in indirect immunofluorescence experiments to detect a stage-specific antigen on the surface of the first larval stage (L1) of the free-living nematode Caenorhabditis elegans, and to detect alterations in the apparent expression of this antigen in two distinct classes of C. elegans mutants. In previously described srf-2 and srf-3 mutants (Politz S. M., M. T. Philipp, M. Estevez, P.J. O'Brien, and K. J. Chin. 1990. Proc. Natl. Acad. Sci. USA. 87:2901-2905), the antigen is not detected on the surface of any stage. Conversely, in srf-(yj43) and other similar mutants, the antigen is expressed on the surface of the first through the fourth (L4) larval stages. To understand the molecular basis of these alterations, the antigen was characterized in gel immunoblotting experiments. After SDS-PAGE separation and transfer to nitrocellulose, M38 detected a protein antigen in extracts of wild-type L1 populations. The antigen was sensitive to digestion by Pronase and O-glycanase (endo-alpha-N-acetylgalactosaminidase), suggesting that it is an O-linked glycoprotein. This antigen was not detected in corresponding extracts of wild-type L4s or srf-2 or srf-3 L1s, but was detected in extracts of srf-(yj43) L4s. The antigen-defective phenotype of srf-3 was epistatic to the heterochronic mutant phenotype of srf-(yj43) in immunofluorescence tests of the srf-3 srf-(yj43) double mutant, suggesting that srf-(yj43) causes incorrect regulation of a pathway of antigen formation that requires wild-type srf-3 activity.


Parasitology ◽  
2004 ◽  
Vol 128 (S1) ◽  
pp. S49-S70 ◽  
Author(s):  
J. S. GILLEARD

There is increasing interest in the use of the free-living nematode Caenorhabditis elegans as a tool for parasitic nematode research and there are now a number of compelling examples of its successful application. C. elegans has the potential to become a standard tool for molecular helminthology researchers, just as yeast is routinely used by molecular biologists to study vertebrate biology. However, in order to exploit C. elegans in a meaningful manner, we need a detailed understanding of the extent to which different aspects of C. elegans biology have been conserved with particular groups of parasitic nematodes. This review first considers the current state of knowledge regarding the conservation of genome organisation across the nematode phylum and then discusses some recent evolutionary development studies in free-living nematodes. The aim is to provide some important concepts that are relevant to the extrapolation of information from C. elegans to parasitic nematodes and also to the interpretation of experiments that use C. elegans as a surrogate expression system. In general, examples have been specifically chosen because they highlight the importance of careful experimentation and interpretation of data. Consequently, the focus is on the differences that have been found between nematode species rather than the similarities. Finally, there is a detailed discussion of the current status of C. elegans as a heterologous expression system to study parasite gene function and regulation using successful examples from the literature.


Nematology ◽  
2014 ◽  
Vol 16 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Matthew Vangheel ◽  
Walter Traunspurger ◽  
Nicole Spann

The antibiotic tetracycline (TC) has been reported in natural systems, a consequence of its abundant usage in farming. TCs are protein synthesis inhibitors that are effective against bacteria but adverse effects on non-target organisms, whilst less well understood, have also been demonstrated. This study is the first investigation into the effects of this common antibiotic on the growth, reproduction and population growth rate (PGR) of the nematode Caenorhabditis elegans. All toxicological endpoints were shown to be affected negatively. TC concentrations as low as 5 mg l−1 (5 ppm) significantly reduced growth and reproduction, and even lower concentrations (3 mg l−1 or 3 ppm) significantly decreased the PGR. These levels are much higher than the TC concentrations detected in surface waters, sediments and soils (0.005-300 ppb). However, although the antibiotic might not pose a direct significant risk to nematodes in the natural environment, its use in RNAi experiments involving C. elegans may cause unwanted effects that influence interpretations of the results.


Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2824
Author(s):  
Yixing Sui ◽  
Laura Mazzucchi ◽  
Parag Acharya ◽  
Yanan Xu ◽  
Geraint Morgan ◽  
...  

Strains of Dunaliella salina microalgae are of considerable research and industrial interest because they hyper-accumulate β-carotene as well as produce high-quality protein. To explore the co-production of valuable compounds in D. salina, this study compared the production of β-carotene, phytoene and amino acids in two strains cultivated under white, red or blue light until no further nitrogen was available. D. salina DF15 (CCAP 19/41 (PLY DF15)) produced more than 12% β-carotene (ash-free dry weight (AFDW) basis), and red light triggered the production of 9-cis β-carotene at a 9-cis/all-trans β-carotene ratio of 1.5. Phytoene production was also evident in D. salina DF15 under all conditions, particularly under blue light. However, the profile of essential amino acids (EAAs) and calculation of the essential amino acid index (EAAI) was less than ideal in terms of protein quality, for both strains. Umami compounds, quantified as monosodium glutamate (MSG) equivalents, indicated a higher equivalent umami concentration (EUC) in D. salina DF15 under red light (3.2 g MSG/100 g AFDW) than in D. salina CCAP19/30. Overall, D. salina DF15 demonstrates valuable traits for further exploration and product optimisation.


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