scholarly journals Identifying Components of a Halobacterium salinarum N-Glycosylation Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Zlata Vershinin ◽  
Marianna Zaretsky ◽  
Ziqiang Guan ◽  
Jerry Eichler

Whereas N-glycosylation is a seemingly universal process in Archaea, pathways of N-glycosylation have only been experimentally verified in a mere handful of species. Toward expanding the number of delineated archaeal N-glycosylation pathways, the involvement of the putative Halobacterium salinarum glycosyltransferases VNG1067G, VNG1066C, and VNG1062G in the assembly of an N-linked tetrasaccharide decorating glycoproteins in this species was addressed. Following deletion of each encoding gene, the impact on N-glycosylation of the S-layer glycoprotein and archaellins, major glycoproteins in this organism, was assessed by mass spectrometry. Likewise, the pool of dolichol phosphate, the lipid upon which this glycan is assembled, was also considered in each deletion strain. Finally, the impacts of such deletions were characterized in a series of biochemical, structural and physiological assays. The results revealed that VNG1067G, VNG1066C, and VNG1062G, renamed Agl25, Agl26, and Agl27 according to the nomenclature used for archaeal N-glycosylation pathway components, are responsible for adding the second, third and fourth sugars of the N-linked tetrasaccharide decorating Hbt. salinarum glycoproteins. Moreover, this study demonstrated how compromised N-glycosylation affects various facets of Hbt. salinarum cell behavior, including the transcription of archaellin-encoding genes.

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2335
Author(s):  
Gabriella Pinto ◽  
Sabrina De Pascale ◽  
Maria Aponte ◽  
Andrea Scaloni ◽  
Francesco Addeo ◽  
...  

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 441
Author(s):  
Yan Yan ◽  
Shuang Chen ◽  
Yao Nie ◽  
Yan Xu

Pyrazines are important compounds in soy sauce aroma type Baijiu (SSAB). In this work, a total of 16 pyrazines were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS) in SSAB. The quantitative results showed that 2,3,5,6-tetramethylpyrazine, 2,6-dimethylpyrazine and 2,3,5-trimethylpyrazine were the three most concentrated pyrazines. The highest odor activity value (OAV) was determined for 2-ethyl-3,5-dimethylpyrazine. Quantitative analysis combined with descriptive sensory analysis revealed that sub-threshold pyrazines (2,3-dimethylpyrazine, 2,3-diethylpyrazine, 2,3-diethyl-5-methylpyrazine and 2-acetyl-3-methylpyrazine) are significantly correlated with the roasted aroma in SSAB. Our study focused on the impact of sub-threshold pyrazines on the perception of roasted aroma in SSAB. The effect of the sub-threshold pyrazines was detected by the addition of various pyrazines in SSAB samples, despite their sub-threshold concentrations. Furthermore, the presence of sub-threshold pyrazines in dilute alcohol solution resulted in a significant reduction in the odor thresholds of supra-threshold pyrazines. Sensory investigation indicated that pyrazines have a synergistic effect on the perception of roasted aroma. The results highlighted the contribution of some pyrazines to the roasted aroma in SSAB despite their sub-threshold concentrations.


2020 ◽  
Vol 58 (6) ◽  
pp. 883-896 ◽  
Author(s):  
Muhammad Zubair Israr ◽  
Dennis Bernieh ◽  
Andrea Salzano ◽  
Shabana Cassambai ◽  
Yoshiyuki Yazaki ◽  
...  

AbstractBackgroundMatrix-assisted laser desorption ionisation (MALDI) mass spectrometry (MS) has been used for more than 30 years. Compared with other analytical techniques, it offers ease of use, high throughput, robustness, cost-effectiveness, rapid analysis and sensitivity. As advantages, current clinical techniques (e.g. immunoassays) are unable to directly measure the biomarker; rather, they measure secondary signals. MALDI-MS has been extensively researched for clinical applications, and it is set for a breakthrough as a routine tool for clinical diagnostics.ContentThis review reports on the principles of MALDI-MS and discusses current clinical applications and the future clinical prospects for MALDI-MS. Furthermore, the review assesses the limitations currently experienced in clinical assays, the advantages and the impact of MALDI-MS to transform clinical laboratories.SummaryMALDI-MS is widely used in clinical microbiology for the screening of microbial isolates; however, there is scope to apply MALDI-MS in the diagnosis, prognosis, therapeutic drug monitoring and biopsy imaging in many diseases.OutlookThere is considerable potential for MALDI-MS in clinic as a tool for screening, profiling and imaging because of its high sensitivity and specificity over alternative techniques.


2021 ◽  
Author(s):  
Arnelle Löbbert ◽  
Sonja Schanzer ◽  
Henrik Krehenwinkel ◽  
Franz Bracher ◽  
Christoph Müller

A novel, validated QuEChERS-based GC-MS/MS method was developed, which will allow the assessment of the impact of pesticides on forest ecosystems.


2021 ◽  
Vol 11 (11) ◽  
pp. 5112
Author(s):  
Julia Vega ◽  
Geniane Schneider ◽  
Bruna R. Moreira ◽  
Carolina Herrera ◽  
José Bonomi-Barufi ◽  
...  

Macroalgae belong to a diverse group of organisms that could be exploited for biomolecule application. Among the biocompounds found in this group, mycosporine-like amino acids (MAAs) are highlighted mainly due to their photoprotection, antioxidant properties, and high photo and thermo-stability, which are attractive characteristics for the development of cosmeceutical products. Therefore, here we revise published data about MAAs, including their biosynthesis, biomass production, extraction, characterization, identification, purification, and bioactivities. MAAs can be found in many algae species, but the highest concentrations are found in red macroalgae, mainly in the order Bangiales, as Porphyra spp. In addition to the species, the content of MAAs can vary depending on environmental factors, of which solar radiation and nitrogen availability are the most influential. MAAs can confer photoprotection due to their capacity to absorb ultraviolet radiation or reduce the impact of free radicals on cells, among other properties. To extract these compounds, different approaches can be used. The efficiency of these methods can be evaluated with characterization and identification using high performance liquid chromatography (HPLC), associated with other apparatus such as mass spectrometry (MS) and nuclear magnetic resonance (NMR). Therefore, the data presented in this review allow a broad comprehension of MAAs and show perspectives for their inclusion in cosmeceutical products.


2020 ◽  
Vol 10 (1) ◽  
pp. 119
Author(s):  
Giorgia Grassi ◽  
Elisa Polledri ◽  
Silvia Fustinoni ◽  
Iacopo Chiodini ◽  
Ferruccio Ceriotti ◽  
...  

The identification of hyperandrogenism in polycystic ovary syndrome (PCOS) is concerning because of the poor accuracy of the androgen immunoassays (IA) and controversies regarding which androgens should be measured. The aim of our study was to evaluate the impact of the assessment of testosterone (T) and androstenedione (A) by liquid chromatography in tandem with mass spectrometry (LC/MS-MS), in the diagnosis of PCOS. We evaluated 131 patients referred for suspected PCOS. Fourteen patients in total were excluded, some because of other diagnosis (n = 7) or incomplete diagnostic workup (n = 7). We measured T and A both by IA and LC-MS/MS in the 117 subjects included. We calculated free T (fT) by the Vermeulen formula and recorded clinical and metabolic data. 73 healthy females served as controls to derive immunoassays (IA) and LC-MS/MS reference intervals for T, fT and A. PCOS was confirmed in 90 subjects by IA and in 93 (+3.3%) by LC-MS/MS. The prevalence of biochemical hyperandrogenism in PCOS by LC-MS/MS increased from 81.7% to 89.2% if A was also considered. The most frequently elevated androgens were fT (73.1%) and A (64.5%) and they had similar levels of accuracy in differentiating PCOS and controls (0.34 ng/dL, Sn 91% Sp 89%; 1.16 ng/mL, Sn 91% Sp 88%, respectively). Free testosterone correlated with body mass index (BMI), homeostatic model assessment (HOMA)-index, glycated hemoglobin (HbA1c), and sex-binding globulin (SHBG). The results confirm that LC-MS/MS is slightly more sensitive than IA in the diagnosis of PCOS with LC-MS/MS detecting higher levels of fT and A. Moreover, assessment of fT and A by LC-MS/MS had a similar level of accuracy in discriminating between PCOs and control subjects. Lastly, fT by LC-MS/MS correlates with adverse metabolic parameters.


Author(s):  
Bruno Nobre Lins Coronado ◽  
Felipe Bruno Santos da Cunha ◽  
Otávio de Toledo Nobrega ◽  
Aline Maria Araujo Martins

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Jiang-Yu Ye ◽  
Yue Pan ◽  
Yong Wang ◽  
Yi-Chao Wang

Abstract Purpose This study utilized the principle that the bacteriorhodopsin (BR) produced by Halobacterium salinarum could increase the hydrogen production of Rhodobacter sphaeroides. H. salinarum are co-cultured with R. sphaeroides to determine the impact of purple membrane fragments (PM) on R. sphaeroides and improve its hydrogen production capacity. Methods In this study, low-salinity in 14 % NaCl domesticates H salinarum. Then, 0–160 nmol of different concentration gradient groups of bacteriorhodopsin (BR) and R. sphaeroides was co-cultivated, and the hydrogen production and pH are measured; then, R. sphaeroides and immobilized BR of different concentrations are used to produce hydrogen to detect the amount of hydrogen. Two-chamber microbial hydrogen production system with proton exchange membrane-assisted proton flow was established, and the system was operated. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. Results H salinarum can still grow well after low salt in 14% NaCl domestication. When the BR concentration is 80 nmol, the highest hydrogen production reached 217 mL per hour. Both immobilized PC (packed cells) and immobilized PM (purple membrane) of H. salinarum could promote hydrogen production of R. sphaeroides to some extent. The highest production of hydrogen was obtained by the coupled system with 40 nmol BR of immobilized PC, which increased from 127 to 232 mL, and the maximum H2 production rate was 18.2 mL−1 h−1 L culture. In the 192 h experiment time, when the potential is 0.3 V, the hydrogen production amount can reach 920 mL, which is 50.3% higher than the control group. Conclusions The stability of the system greatly improved after PC was immobilized, and the time for hydrogen production of R. sphaeroides significantly extended on same condition. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. These results are helpful to build a hydrogen production-coupled system by nitrogenase of R. sphaeroides and proton pump of H. salinarum. Graphical abstract


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