HPLC Determination of Bioactive Sulfur Compounds, Amino Acids and Biogenic Amines in Biological Specimens

Bioconversion of High-Calorie Potato Starch to Low-Calorie β-Glucan via 3D Printing Using Pleurotus eryngii Mycelia

Edible fungi play an important role in material and energy cycling. This study explored the role of Pleurotus eryngii mycelia in the transformation of potato high-calorie starch to low-calorie β-glucan. First, the 3D printing performance of the potato medium was optimized. After inoculating the fermentation broth of Pleurotus eryngii in 3D printing, we studied the microstructure and material composition of the product. Along with the increase in 3D printing filling ratio, the starch content of the culture product decreased from 84.18% to 60.35%, while the starch content in the solid medium prepared using the mold was 67.74%. The change in β-glucan content in cultured products was opposite to that of starch, and the content of the culture product increased from 12.57% to 24.31%, while the β-glucan content in the solid medium prepared using the mold was 22.17%. The amino acid composition and content of the 3D printing culture system and solid culture products prepared using the mold were similar. The 3D printing culture system promoted the bioconversion efficiency of mycelia. It also showed high application potential of Pleurotus eryngii mycelia for the preparation of low-calorie food.

Chemistry of Outlandish Natural Products Belonging to Sulfur Metabolism: Unrevealed Green Syntheses and Separation Strategies from the Cavallini’s Old School

The last century has been very important from the point of view of research and investigation in the fields of the chemistry and biochemistry of sulfur-containing natural products. One of the most important contributions to the discovery and study of human sulfur-containing metabolites was performed by the research group of Professor Doriano Cavallini at Sapienza University of Rome, during the last 80 years. His research brought to light the discovery of unusual sulfur metabolites that were chemically synthesized and determined in different biological specimens. Most of his synthetical strategies were performed in aqueous conditions, which nowadays can be considered totally in line with the recent concepts of the green chemistry. The aim of this paper is to describe and summarize synthetic procedures, and purification and analytical methods from the Cavallini’s school, with the purpose to provide efficient and green methodologies for the preparation and obtainment of peculiar unique sulfur-containing metabolites.

Formation, Analytical Methods, Change Tendency, and Control Strategies of Biogenic Amines in Canned Aquatic Products: A Systematic Review

ABSTRACT

Biogenic amines (BAs) are organic compounds with low molecular weight and can be used as indicators of the quality and safety of canned aquatic products during processing and storage. However, excess of these amines can cause foodborne poisoning. Therefore, the determination, analysis, and prevention of BAs are of great importance. This article focuses on the sources, formation, and pretreatment methods, as well as analytical techniques, change tendency, and control techniques of BAs, with the aim of promoting more appropriate analysis of canned aquatic products to provide a reference for the food industries.

HIGHLIGHTS

Determination of Free Amino Acids in Banlangen Granule and its Fractions by Solid Phase Extraction Combined with Ion-pair Hig-h Perfor mance Liquid Chromatography using a Corona-charged Aerosol Detector (SPE-HPLC-CAD)

Background:

Banlangen granules are broad-spectrum effective antiviral drugs, and have a large clinical demand in China. Free amino acid is one of the main antiviral active ingredients of Banlangen granules. The pre-processing of samples by the existing pre-column derivatization reversed- HPLC method is complicated. Therefore, the determination of free amino acids (AAs) by underivatized ion-pair HPLC-CAD is advantageous for simplifying the preparation process and improving sensitivity.

Objective:

To better optimize AAs analysis methods, here a sensitive SPE-HPLC-CAD method with a better resolution was established for the determination of underivatized AAs in Banlangen Granule for the first time.

Method:

The analytes were separated only by HPLC using a Hypercarb column with gradient elution of solvent A (20 mM nonafluorovaleric Acid in water) and solvent B (0.3% trifluoroacetic acid in acetonitrile-0.3% trifluoroacetic acid in water (1:9, v/v)) at a flow rate of 0.15 mL/min. N2 gas pressure and evaporation temperature of CAD were held at a constant 58.6 psi and 60 ℃, respectively.

Results:

This method was linear over the respective concentration range of six amino acids. The precision, accuracy, stability and recovery were satisfactory in all samples examined. And the method was successfully applied to determination of free amino acids in Banlangen granules and its fractions. The total contents of six amino acids in 28 batches of Banlangen Granule were between 1.36 mg/g-11.62 mg/g.

Conclusion:

The proposed method could be a simple, accurate and sensitive alternative approach for the determination of free AAs in Banlangen Granule.

Fluorometric Optimized Determination of Total Glutathione in Erythrocytes

Glutathione is a tripeptide natural product characterized by a non-canonical peptide bond with an amide moiety linking the nitrogen of cysteine to the γ-carboxyl of glutamate, and is found ubiquitously in nature, in animals, plants and microorganisms. One of the most abundant biological matrices is represented by erythrocytes, being glutathione the only sulfur-containing mechanism for the red blood cell oxidative protection. Several analytical methods for glutathione determination from different samples are described in the literature and most of these methods are based on the use of high-performance liquid chromatography. HPLC equipment is not available in all the biochemical laboratories, and, moreover, displays lot of economic and ecological limitations, including organic solvent consumption and time-consuming analysis. Here, an organic-free high-throughput fluorometric methodology for the analysis of total glutathione in erythrocytes is reported, avoiding the use of time-consuming and not-sustainable techniques.

Chemistry and Biochemistry of Sulfur Natural Compounds: Key Intermediates of Metabolism and Redox Biology

Sulfur contributes significantly to nature chemical diversity and thanks to its particular features allows fundamental biological reactions that no other element allows. Sulfur natural compounds are utilized by all living beings and depending on the function are distributed in the different kingdoms. It is no coincidence that marine organisms are one of the most important sources of sulfur natural products since most of the inorganic sulfur is metabolized in ocean environments where this element is abundant. Terrestrial organisms such as plants and microorganisms are also able to incorporate sulfur in organic molecules to produce primary metabolites (e.g., methionine, cysteine) and more complex unique chemical structures with diverse biological roles. Animals are not able to fix inorganic sulfur into biomolecules and are completely dependent on preformed organic sulfurous compounds to satisfy their sulfur needs. However, some higher species such as humans are able to build new sulfur-containing chemical entities starting especially from plants' organosulfur precursors. Sulfur metabolism in humans is very complicated and plays a central role in redox biochemistry. The chemical properties, the large number of oxidation states, and the versatile reactivity of the oxygen family chalcogens make sulfur ideal for redox biological reactions and electron transfer processes. This review will explore sulfur metabolism related to redox biochemistry and will describe the various classes of sulfur-containing compounds spread all over the natural kingdoms. We will describe the chemistry and the biochemistry of well-known metabolites and also of the unknown and poorly studied sulfur natural products which are still in search for a biological role.

Maternal Immune Activation in Mice Only Partially Recapitulates the Autism Spectrum Disorders Symptomatology

Prenatal viral/bacterial infections are considered risk factors for autism spectrum disorders (ASD) and rodent models of maternal immune activation (MIA) have been developed and extensively used in preclinical studies. Poly inosinic-cytidylic acid (Poly I:C) was injected in C57BL6/J dams to mimic a viral infection on gestational day 12.5; the experimental design includes 10/12 litters in each treatment group and data were analysed always considering the litter-effect; neonatal (spontaneous motor behaviour and ultrasonic vocalizations) and adult [open field, marble burying, social approach, fear conditioning, prepulse inhibition (PPI)] offspring of both sexes were tested. In vivo magnetic resonance imaging/spectroscopy (MRI-MRS) and high-performance liquid chromatography (HPLC) to quantify both aminoacid and/or neurotransmitter concentration in cortical and striatal regions were also carried out. In both sexes high levels of repetitive motor responses and sensory gating deficits in PPI were the more striking effects of Poly I:C, whereas no alteration of social responses were evidenced. Poly I:C treatment did not affect mean values, but, intriguingly, increased variability in the levels of four aminoacids (aspartate glycine and GABA) selectively in males. As a whole prenatal Poly I:C induced relevant long-term alterations in explorative-stereotyped motor responses and in sensory gating, sparing cognitive and social competences. When systematically assessing differences between male and female siblings within each litter, no significant sex differences were evident except for increased variability of four aminoacid levels in male brains. As a whole, prenatal Poly I:C paradigms appear to be a useful tool to investigate the profound and translationally-relevant effects of developmental immune activation on brain and behavioural development, not necessarily recapitulating the full ASD symptomatology.

Chromatographic determination of biogenic amines in four typical Italian cheeses: correlations with processing and nutritional characteristics through a chemometric approach

BACKGROUND

The presence of biogenic amines (BAs) fermented food is well known. They may affect food quality, posing health risks. In this work, four typical Italian cheeses, exported worldwide, were analyzed to determine the possible presence of BAs. The cheese samples were analyzed untreated and having been subjected to common or incorrect consumer handling (domestic grating, unrefrigerated storage).

RESULTS

A chromatographic-amperometric method was developed and validated. Extraction of BAs was performed by the addition of eluent, determining matrix effect and recovery of biogenic amines directly within the cheeses. Biogenic amines were present in the range of 0.019-0.044 g kg^-1 , well below the current EU limit. Home-manipulation confirmed recontamination of the cheese. The contents of BAs were correlated with the main processing parameters and with the nutritional properties of the four cheeses through the multivariate statistical analysis (principal component analysis). This is believed to be the first study that presents these correlations.

CONCLUSION

This study highlights correlations among BAs and carbohydrates, and anticorrelations with pH and, to a lesser extent, with moisture. Interestingly, BAs are correlated with fat content. This correlation was confirmed by a new principal component analysis performed on our data set with additional data from the literature. © 2019 Society of Chemical Industry.

Proline synthesis in developing microspores is required for pollen development and fertility

BACKGROUND

In many plants, the amino acid proline is strongly accumulated in pollen and disruption of proline synthesis caused abortion of microspore development in Arabidopsis. So far, it was unclear whether local biosynthesis or transport of proline determines the success of fertile pollen development.

RESULTS

We analyzed the expression pattern of the proline biosynthetic genes PYRROLINE-5-CARBOXYLATE SYNTHETASE 1 & 2 (P5CS1 & 2) in Arabidopsis anthers and both isoforms were strongly expressed in developing microspores and pollen grains but only inconsistently in surrounding sporophytic tissues. We introduced in a p5cs1/p5cs1 p5cs2/P5CS2 mutant background an additional copy of P5CS2 under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter, the tapetum-specific LIPID TRANSFER PROTEIN 12 (Ltp12) promoter or the pollen-specific At5g17340 promoter to determine in which site proline biosynthesis can restore the fertility of proline-deficient microspores. The specificity of these promoters was confirmed by β-glucuronidase (GUS) analysis, and by direct proline measurement in pollen grains and stage-9/10 anthers. Expression of P5CS2 under control of the At5g17340 promoter fully rescued proline content and normal morphology and fertility of mutant pollen. In contrast, expression of P5CS2 driven by either the Ltp12 or CaMV35S promoter caused only partial restoration of pollen development with little effect on pollen fertility.

CONCLUSIONS

Overall, our results indicate that proline transport is not able to fulfill the demand of the cells of the male germ line. Pollen development and fertility depend on local proline biosynthesis during late stages of microspore development and in mature pollen grains.