Stearic acid represents one of the most abundant fatty acids in the Western diet and profoundly regulates health and diseases of animals and human beings. We previously showed that stearic acid ...supplementation promoted development of the terrestrial model nematode Caenorhabditis elegans in chemically defined CeMM food environment. However, whether stearic acid regulates development of other nematodes remains unknown. Here, we found that dietary supplementation with stearic acid could promote the development of the marine nematode Litoditis marina, belonging to the same family as C. elegans, indicating the conserved roles of stearic acid in developmental regulation. We further employed transcriptome analysis to analyze genome-wide transcriptional signatures of L. marina with dietary stearic acid supplementation. We found that stearic acid might promote development of L. marina via upregulation of the expression of genes involved in aminoacyl-tRNA biosynthesis, translation initiation and elongation, ribosome biogenesis, and transmembrane transport. In addition, we observed that the expression of neuronal signaling-related genes was decreased. This study provided important insights into how a single fatty acid stearic acid regulates development of marine nematode, and further studies with CRISPR genome editing will facilitate demonstrating the molecular mechanisms underlying how a single metabolite regulates animal development and health.
Diets regulate animal development, reproduction, and lifespan. However, the underlying molecular mechanisms remain elusive. We previously showed that a chemically defined CeMM diet attenuates the ...development and promotes the longevity of C. elegans, but whether it impacts other nematodes is unknown. Here, we studied the effects of the CeMM diet on the development and longevity of the marine nematode Litoditis marina, which belongs to the same family as C. elegans. We further investigated genome-wide transcriptional responses to the CeMM and OP50 diets for both nematodes, respectively. We observed that the CeMM diet attenuated L. marina development but did not extend its lifespan. Through KEEG enrichment analysis, we found that many of the FOXO DAF-16 signaling and lysosome and xenobiotic metabolism related genes were significantly increased in C. elegans on the CeMM diet, which might contribute to the lifespan extension of C. elegans. Notably, we found that the expression of lysosome and xenobiotic metabolism pathway genes was significantly down-regulated in L. marina on CeMM, which might explain why the CeMM diet could not promote the lifespan of L. marina compared to bacterial feeding. Additionally, the down-regulation of several RNA transcription and protein generation and related processes genes in C. elegans on CeMM might not only be involved in extending longevity, but also contribute to attenuating the development of C. elegans on the CeMM diet, while the down-regulation of unsaturated fatty acids synthesis genes in L. marina might contribute to slow down its growth while on CeMM. This study provided important insights into how different diets regulate development and lifespan, and further genetic analysis of the candidate gene(s) of development and longevity will facilitate exploring the molecular mechanisms underlying how diets regulate animal physiology and health in the context of variable nutritional environments.
Capacity is an important tool in decision-making under risk and uncertainty and multi-criteria decision-making. When learning a capacity-based model, it is important to be able to generate uniformly ...a capacity. Due to the monotonicity constraints of a capacity, this task reveals to be very difficult. The classical Random Node Generator (RNG) algorithm is a fast-running speed capacity generator, however with poor performance. In this paper, we firstly present an exact algorithm for generating a n elements' general capacity, usable when n < 5. Then, we present an improvement of the classical RNG by studying the distribution of the value of each element of a capacity. Furthermore, we divide it into two cases, the first one is the case without any conditions, and the second one is the case when some elements have been generated. Experimental results show that the performance of this improved algorithm is much better than the classical RNG while keeping a very reasonable computation time.
We reported a special type of lamination formed in the sediments of Lake Xiaolongwan, northeastern China. The lamination consists of light- and brown-colored laminate couplets in the thin sections. ...The brown-colored layer is composed mainly of dinoflagellate cysts. The grey-colored layer consists of other organic and siliceous matter (plant detritus, diatoms, chrysophyte cysts) and clastics. Preliminary sediment trap results show that a distinct peak of dinocyst flux occurred in November. The dinocyst flux maximum also corresponds to the peaks of diatom flux and chrysophyte stomatocyst flux. These suggest that "red tide blooms" occur in this freshwater lake. We speculate that the dinocyst flux maximum could be related to autumn overturn due to increased nutrients, and the availability of cysts for germination from the lake bottom. Additionally, it may also reflect increasing dissolved organic matter after leaf fall. An independent chronology derived from
137
Cs and
210
Pb shows a good agreement with counted laminations. From the sediment trap data and the independent chronology data, the dinocyst microlaminae appear to be annually laminated, and probably could be called dinocyst varves. Although vegetative (thecate stage) cells of
Peridinium volzii
and
Ceratium furcoides
are found in the water samples, it is not possible to relate the dinocysts to these two dinoflagellate species. Based on morphological and ecological analyses, we suggested that they have affinities with species of
Peridinium
(
sensu lato
), most probably to
P. inconspicuum
. Detailed investigations should be carried out to understand the red tide history in this freshwater lake. Annually laminated dinocyst microlayers in freshwater and marine sediments not only provide an uncommon archive for understanding the history of red tides and harmful algal blooms, and why and how certain species periodically bloom over several thousands years, but also provide important records of paleoenvironmental and paleoclimatic changes at seasonal to annual resolution.
The cell line is an important experimental tool to investigate the mechanism of host-pathogen interactions and to diagnose and cure diseases. However, their application in aquatic invertebrates is ...limited because they lack immortalized cell lines. The brine shrimp Artemia produces encysted diapause gastrula embryos under stress conditions. The biological advantages of Artemia embryos, such as quick switching on of the cell cycle upon short-term hydration and easy control of microbial contamination via decapsulation, makes them a candidate material for cell culture in vitro. This study identified five subpopulations of embryonic cells at the gastrula stage based on morphological characteristics. After 3–4 h of hydration, embryonic cells were derived from the cysts and successfully cultured for 10 days in 1.2 × L-15 medium containing 15% fetal bovine serum, with a cell viability of more than 90%. Using this primary cell culture system, Vibrio anguillarum and V. parahaemolyticus strains were screened as possible infectious Vibrio strains using laser confocal microscopy observations. The pathological features of viable Vibrio-challenged embryonic cells were further studied by comparing formaldehyde-inactivated and autoclaved Vibrio and polystyrene beads using SEM observation. The results confirmed that both Vibrio strains could challenge embryonic cells and cause some cytopathological features, such as cell aggregation and concaves. Our study provides the first evidence that in vitro cell culture of Artemia embryos can be used to demonstrate the characteristics of Vibrio infection. The primary cell culture system established in this study will facilitate research on the mechanism of host-pathogen interactions in aquatic animals.
•Artemia embryos are good experimental materials which make it a candidate for cell culture in vitro.•Embryonic cells of Artemia were successfully cultured for 10 days in a suitable cell culture system, with cell viability of more than 90%.•The result clarified that embryonic cell in vitro were caused some pathologic features in process of Vibrio challenged.•The established primary cell culture system will facilitate to the mechanism of host-pathogen interactions of aquatic animals and stem cell fates determination.
Dietary intake and nutrient composition regulate animal growth and development; however, the underlying mechanisms remain elusive. Our previous study has shown that either the mammalian deafness ...homolog gene
tmc-1
or its downstream acetylcholine receptor gene
eat-2
attenuates
Caenorhabditis elegans
development in a chemically defined food CeMM (
C. elegans
maintenance medium) environment, but the underpinning mechanisms are not well-understood. Here, we found that, in CeMM food environment, for both
eat-2
and
tmc-1
fast-growing mutants, several fatty acid synthesis and elongation genes were highly expressed, while many fatty acid β-oxidation genes were repressed. Accordingly, dietary supplementation of individual fatty acids, such as monomethyl branch chain fatty acid C17ISO, palmitic acid and stearic acid significantly promoted wild-type animal development on CeMM, and mutations in either C17ISO synthesis gene
elo-5
or
elo-6
slowed the rapid growth of
eat-2
mutant. Tissue-specific rescue experiments showed that
elo-6
promoted animal development mainly in the intestine. Furthermore, transcriptome and metabolome analyses revealed that
elo-6
/C17ISO regulation of
C. elegans
development may be correlated with up-regulating expression of cuticle synthetic and hedgehog signaling genes, as well as promoting biosynthesis of amino acids, amino acid derivatives and vitamins. Correspondingly, we found that amino acid derivative S-adenosylmethionine and its upstream metabolite methionine sulfoxide significantly promoted
C. elegans
development on CeMM. This study demonstrated that C17ISO, palmitic acid, stearic acid, S-adenosylmethionine and methionine sulfoxide inhibited or bypassed the TMC-1 and EAT-2-mediated attenuation of development via metabolic remodeling, and allowed the animals to adapt to the new nutritional niche.
