scholarly journals Mycosporine-Like Amino Acids (MAAs) in Zooplankton

Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 72 ◽  
Author(s):  
Samuel Hylander

Organisms have different adaptations to avoid damage from ultraviolet radiation and one such adaptation is the accumulation of mycosporine-like amino acids (MAAs). These compounds are common in aquatic taxa but a comprehensive review is lacking on their distribution and function in zooplankton. This paper shows that zooplankton MAA concentrations range from non-detectable to ~13 µg mgDW−1. Copepods, rotifers, and krill display a large range of concentrations, whereas cladocerans generally do not contain MAAs. The proposed mechanisms to gain MAAs are via ingestion of MAA-rich food or via symbiotic bacteria providing zooplankton with MAAs. Exposure to UV-radiation increases the concentrations in zooplankton both via increasing MAA concentrations in the phytoplankton food and due to active accumulation. Concentrations are generally low during winter and higher in summer and females seem to deposit MAAs in their eggs. The concentrations of MAAs in zooplankton tend to increase with altitude but only up to a certain altitude suggesting some limitation for the uptake. Shallow and UV-transparent systems tend to have copepods with higher concentrations of MAAs but this has only been shown in a few species. A high MAA concentration has also been shown to lead to lower UV-induced mortality and an overall increased fitness. While there is a lot of information on MAAs in zooplankton we still lack understanding of the potential costs and constraints for accumulation. There is also scarce information in some taxa such as rotifers as well as from systems in tropical, sub(polar) areas as well as in marine systems in general.

2019 ◽  
Author(s):  
Clara M. Agapie ◽  
Melissa Sampson ◽  
William Gee

The work describes a new chemical means of visualising latent fingerprints (fingermarks) using tropolone. Tropolone reacts with amino acids within the fingermark residue to form adducts that absorb UV radiation. These adducts provide useful contrast on highly-fluorescent prous surfaces will illuminated with UV radiation. The conjugated seven-membered ring of the tropolone adduct can be reacted further diazonium salts, which is demonstrated here with formation of two dyes. The methodology is extremely rapid, occurring in minutes with mild heating, and can be applied before ninhydrin in a chemical detection sequence. <br>


Author(s):  
Shen Jean Lim ◽  
Brenton Davis ◽  
Danielle Gill ◽  
John Swetenburg ◽  
Laurie C Anderson ◽  
...  

Abstract Lucinid bivalves harbor environmentally acquired, chemosynthetic, gammaproteobacterial gill endosymbionts. Lucinid gill microbiomes, which may contain other gammaproteobacterial and/or spirochete taxa, remain under-sampled. To understand inter-host variability of the lucinid gill microbiome, specifically in the bacterial communities, we analyzed the microbiome content of Stewartia floridana collected from Florida. Sampled gills contained a monospecific gammaproteobacterial endosymbiont expressing lithoautotrophic, mixotrophic, diazotrophic, and C1 compound oxidation-related functions previously characterized in similar lucinid species. Another low-abundance Spirochaeta-like species in ∼72% of the sampled gills was most closely related to Spirochaeta-like species in another lucinid Phacoides pectinatus and formed a clade with known marine Spirochaeta symbionts. The spirochete expressed genes were involved in heterotrophy and the transport of sugars, amino acids, peptides, and other substrates. Few muscular and neurofilament genes from the host and none from the gammaproteobacterial and spirochete symbionts were differentially expressed among quadrats predominantly covered with seagrass species or 80% bare sand. Our results suggest that spirochetes are facultatively associated with S. floridana, with potential scavenging and nutrient cycling roles. Expressed stress- and defense-related functions in the host and symbionts also suggest species-species communications, which highlight the need for further study of the interactions among lucinid hosts, their microbiomes, and their environment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip Newsholme

AbstractVarious nutrients can change cell structure, cellular metabolism, and cell function which is particularly important for cells of the immune system as nutrient availability is associated with the activation and function of diverse immune subsets. The most important nutrients for immune cell function and fate appear to be glucose, amino acids, fatty acids, and vitamin D. This perspective will describe recently published information describing the mechanism of action of prominent nutritional intervention agents where evidence exists as to their action and potency.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maximilian Fichtner ◽  
Stefan Schuster ◽  
Heiko Stark

AbstractAging research is a very popular field of research in which the deterioration or decline of various physiological features is studied. Here we consider the molecular level, which can also have effects on the macroscopic level. The proteinogenic amino acids differ in their susceptibilities to non-enzymatic modification. Some of these modifications can lead to protein damage and thus can affect the form and function of proteins. For this, it is important to know the distribution of amino acids between the protein shell/surface and the core. This was investigated in this study for all known structures of peptides and proteins available in the PDB. As a result, it is shown that the shell contains less susceptible amino acids than the core with the exception of thermophilic organisms. Furthermore, proteins could be classified according to their susceptibility. This can then be used in applications such as phylogeny, aging research, molecular medicine, and synthetic biology.


2021 ◽  
pp. 56-57
Author(s):  
Наталья Игоревна Федянина ◽  
Ольга Вячеславовна Карастоянова ◽  
Надежда Вячеславовна Коровкина

Представлены результаты исследования влияния обработки свежих шампиньонов ультрафиолетовым излучением в диапазоне А различными дозами на изменение текстуры. Построена математическая модель зависимости предельной хранимоспособности по целевому показателю грибов от дозы облучения, и установлены оптимальные режимы обработки. The results of a study of the effect of processing fresh champignons with ultraviolet radiation in the A range with various doses on the change in texture are presented. A mathematical model of the dependence of the limiting storage capacity for the target indicator of mushrooms on the radiation dose has been built and the optimal processing modes have been established.


2016 ◽  
Vol 82 (19) ◽  
pp. 5951-5959 ◽  
Author(s):  
Paul M. D'Agostino ◽  
Vivek S. Javalkote ◽  
Rabia Mazmouz ◽  
Russell Pickford ◽  
Pravin R. Puranik ◽  
...  

ABSTRACTThe mycosporine-like amino acids (MAAs) are a group of small molecules with a diverse ecological distribution among microorganisms. MAAs have a range of physiological functions, including protection against UV radiation, making them important from a biotechnological perspective. In the present study, we identified a putative MAA (mys) gene cluster in two New Zealand isolates ofScytonemacf.crispum(UCFS10 and UCFS15). Homology to “Anabaena-type”mysclusters suggested that this cluster was likely to be involved in shinorine biosynthesis. Surprisingly, high-performance liquid chromatography analysis ofS. cf.crispumcell extracts revealed a complex MAA profile, including shinorine, palythine-serine, and their hexose-bound variants. It was hypothesized that a short-chain dehydrogenase (UCFS15_00405) encoded by a gene adjacent to theS. cf.crispummyscluster was responsible for the conversion of shinorine to palythine-serine. Heterologous expression of MysABCE and UCFS15_00405 inEscherichia coliresulted in the exclusive production of the parent compound shinorine. Taken together, these results suggest that shinorine biosynthesis inS. cf.crispumproceeds via anAnabaena-type mechanism and that the genes responsible for the production of other MAA analogues, including palythine-serine and glycosylated analogues, may be located elsewhere in the genome.IMPORTANCERecently, New Zealand isolates ofS. cf.crispumwere linked to the production of paralytic shellfish toxins for the first time, but no other natural products from this species have been reported. Thus, the species was screened for important natural product biosynthesis. The mycosporine-like amino acids (MAAs) are among the strongest absorbers of UV radiation produced in nature. The identification of novel MAAs is important from a biotechnology perspective, as these molecules are able to be utilized as sunscreens. This study has identified two novel MAAs that have provided several new avenues of future research related to MAA genetics and biosynthesis. Further, we have revealed that the genetic basis of MAA biosynthesis may not be clustered on the genome. The identification of the genes responsible for MAA biosynthesis is vital for future genetic engineering.


mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Jingwei Cai ◽  
Robert G. Nichols ◽  
Imhoi Koo ◽  
Zachary A. Kalikow ◽  
Limin Zhang ◽  
...  

ABSTRACTThe gut microbiota is susceptible to modulation by environmental stimuli and therefore can serve as a biological sensor. Recent evidence suggests that xenobiotics can disrupt the interaction between the microbiota and host. Here, we describe an approach that combinesin vitromicrobial incubation (isolated cecal contents from mice), flow cytometry, and mass spectrometry- and1H nuclear magnetic resonance (NMR)-based metabolomics to evaluate xenobiotic-induced microbial toxicity. Tempol, a stabilized free radical scavenger known to remodel the microbial community structure and functionin vivo, was studied to assess its direct effect on the gut microbiota. The microbiota was isolated from mouse cecum and was exposed to tempol for 4 h under strict anaerobic conditions. The flow cytometry data suggested that short-term tempol exposure to the microbiota is associated with disrupted membrane physiology as well as compromised metabolic activity. Mass spectrometry and NMR metabolomics revealed that tempol exposure significantly disrupted microbial metabolic activity, specifically indicated by changes in short-chain fatty acids, branched-chain amino acids, amino acids, nucleotides, glucose, and oligosaccharides. In addition, a mouse study with tempol (5 days gavage) showed similar microbial physiologic and metabolic changes, indicating that thein vitroapproach reflectedin vivoconditions. Our results, through evaluation of microbial viability, physiology, and metabolism and a comparison ofin vitroandin vivoexposures with tempol, suggest that physiologic and metabolic phenotyping can provide unique insight into gut microbiota toxicity.IMPORTANCEThe gut microbiota is modulated physiologically, compositionally, and metabolically by xenobiotics, potentially causing metabolic consequences to the host. We recently reported that tempol, a stabilized free radical nitroxide, can exert beneficial effects on the host through modulation of the microbiome community structure and function. Here, we investigated a multiplatform phenotyping approach that combines high-throughput global metabolomics with flow cytometry to evaluate the direct effect of tempol on the microbiota. This approach may be useful in deciphering how other xenobiotics directly influence the microbiota.


Author(s):  
Daniela Glatzová ◽  
Harsha Mavila ◽  
Maria Chiara Saija ◽  
Tomáš Chum ◽  
Lukasz Cwiklik ◽  
...  

ABSTRACTLAT is a critical regulator of T cell development and function. It organises signalling events at the plasma membrane. However, the mechanism, which controls LAT localisation at the plasma membrane is not fully understood. Here, we studied the impact of helix-breaking amino acids, two prolines and one glycine, in the transmembrane segment on localisation and function of LAT. Using in silico analysis, confocal and superresolution imaging and flow cytometry we demonstrate that central proline residue destabilises transmembrane helix by inducing a kink. The helical structure and dynamics is further regulated by glycine and another proline residue in the luminal part of LAT transmembrane domain. Replacement of these residues with aliphatic amino acids reduces LAT dependence on palmitoylation for sorting to the plasma membrane. However, surface expression of these mutants is not sufficient to recover function of non-palmitoylated LAT in stimulated T cells. These data indicate that geometry and dynamics of LAT transmembrane segment regulate its localisation and function in immune cells.


Author(s):  
M. A. Shorikov ◽  
O. N. Sergeeva ◽  
M. G. Lapteva ◽  
N. A. Peregudov ◽  
B. I. Dolgushin

Proximal extrahepatic bile ducts are the biliary tree segment within formal boundaries from cystic ductcommon hepatic duct junction to sectoral hepatic ducts. Despite being a focus of attention of diagnostic and interventional radiologists, endoscopists, hepatobiliary surgeons and transplantologists they weren’t comprehensively described in available papers. The majority of the authors regard bile duct confluence as a group of merging primitively arranged tubes providing bile flow. The information on the proximal extrahepatic bile duct embryonal development, variant anatomy, innervation, arterial, venous and lymphatic supply is too general and not detailed. The present review brought together and systemized exiting to the date data on anatomy and function of this biliary tract portion. Unique, different from the majority of hollow organs organization of the proximal extrahepatic bile duct adapts them to the flow of the bile, i.e. viscous aggressive due to pH about 8.0 and detergents fluid, under higher wall pressure than in other parts of biliary tree. 


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