The report of anthocyanins in the betalain-pigmented genus Hylocereus is not well evidenced and is not a strong basis to refute the mutual exclusion paradigm

Here we respond to the paper entitled “Contribution of anthocyanin pathways to fruit flesh coloration in pitayas” (Fan et al., BMC Plant Biol 20:361, 2020). In this paper Fan et al. 2020 propose that the anthocyanins can be detected in the betalain-pigmented genus Hylocereus, and suggest they are responsible for the colouration of the fruit flesh. We are open to the idea that, given the evolutionary maintenance of fully functional anthocyanin synthesis genes in betalain-pigmented species, anthocyanin pigmentation might co-occur with betalain pigments, as yet undetected, in some species. However, in absence of the LC-MS/MS spectra and co-elution/fragmentation of the authentic standard comparison, the findings of Fan et al. 2020 are not credible. Furthermore, our close examination of the paper, and re-analysis of datasets that have been made available, indicate numerous additional problems. Namely, the failure to detect betalains in an untargeted metabolite analysis, accumulation of reported anthocyanins that does not correlate with the colour of the fruit, absence of key anthocyanin synthesis genes from qPCR data, likely mis-identification of key anthocyanin genes, unreproducible patterns of correlated RNAseq data, lack of gene expression correlation with pigmentation accumulation, and putative transcription factors that are weak candidates for transcriptional up-regulation of the anthocyanin pathway.

Stable isotope and chemical inhibition analyses suggested the existence of a non-mevalonate-like pathway in the yeast Yarrowia lipolytica

Methyl erythritol phosphate (MEP) is the metabolite found in the MEP pathway for isoprenoid biosynthesis, which is known to be utilized by plants, algae, and bacteria. In this study, an unprecedented observation was found in the oleaginous yeast Yarrowia lipolytica, in which one of the chromatographic peaks was annotated as MEP when cultivated in the nitrogen limiting condition. This finding raised an interesting hypothesis of whether Y. lipolytica utilizes the MEP pathway for isoprenoid biosynthesis or not, because there is no report of yeast harboring the MEP pathway. Three independent approaches were used to investigate the existence of the MEP pathway in Y. lipolytica; the spiking of the authentic standard, the MEP pathway inhibitor, and the 13C labeling incorporation analysis. The study suggested that the mevalonate and MEP pathways co-exist in Y. lipolytica and the nitrogen limiting condition triggers the utilization of the MEP pathway in Y. lipolytica.

Structural Characterisation of Dimeric Esters in α-Pinene Secondary Organic Aerosol Using N2 and CO2 Ion Mobility Mass Spectrometry

The atmospheric oxidation of monoterpenes leads to the formation of secondary organic aerosol (SOA). While numerous works have been carried out in the past to characterise SOA at a molecular level, the structural elucidation of SOA compounds remains challenging owing to the lack of authentic standard compounds. In this work, the structures of α-pinene originating dimeric esters in SOA with m/z 357 (C17H25O8-) and m/z 367 (C19H27O7-) were characterised using UPLC/ESI(-)IMS-TOFMS2 (ultra-performance liquid chromatography coupled to ion mobility spectrometry tandem time-of-flight mass spectrometry). The measured collision cross-section (ΩN2) values were compared to theoretically calculated ΩN2 values. Selected product ions of dimeric compounds and the authentic standard compounds of product ions were subjected to CO2-IMS-TOFMS for more detailed structural characterisation. Our results were consistent with previously reported subunits of the m/z 357 (terpenylic acid and cis-pinic acid), and the m/z 367 (10-hydroxy-cis-pinonic acid and cis-pinic acid) ions. The measured and calculated ΩN2 values of m/z 367 ions further support the conclusion of earlier structural characterisation; however, the structure of the m/z 357 ion remains vague and requires further characterisation studies with a synthesised reference compound.

Influence of the p-hydroxyphenyl/guaiacyl ratio on the biphenyl and β-5 contents in compression wood lignins

Reaction woods of three softwoods, Pinus merkusii, Cryptomeria japonica and Cedrus deodara, were investigated by alkaline nitrobenzene oxidation (NBO) to characterize the condensed-type structures in compression wood lignins. A novel biphenyl-type NBO product carrying guaiacyl (G)- and p-hydroxyphenyl (H)-units, dehydrovanillin-p-hydroxybenzaldehyde (HG-biphenyl product), was identified using the authentic standard compound. On the basis of the yield of this novel NBO product, as well as those of GG-biphenyl-, β-5-, and uncondensed-type products [e.g. dehydrodivanillin, 5-formylvanillin, vanillin and p-hydroxybenzaldehyde], the compression wood lignins contained more HG-type biphenyl and H-type β-5 structures than the opposite wood lignins. The increase in the condensed-type structure content was largely offset by the decreases in the content of GG-biphenyl and G-type β-5 structures. Consequently, the relative yields of biphenyl, β-5 and uncondensed-type NBO products were very similar between the compression wood and the opposite wood, even though the H-unit having no methoxy group on its aromatic ring can be assumed to have a greater probability to form condensed-type structures during lignin biosynthesis than the G-unit.

Simple Preparation of Diverse Neoagaro-Oligosaccharides

A simple method for obtaining pure and well-defined oligosaccharides was established by hydrolyzing agar with β-agarase from Vibrio natriegens. The conditions for enzymolysis were optimized as follows: a temperature of 45 °C, a pH of 8.5, a substrate concentration of 0.3%, an enzyme amount of 100 U/g and an enzymolysis time of 20 h. Neoagaro-oligosaccharides with different degrees of polymerization were obtained by hydrolyzing agar with β-agarase for different lengths of time. After removing pigments using activated carbon and salts by dialyzing, the enzyme hydrolysis solution was separated with Bio-Gel P2 column chromatography. Neoagaro-oligosaccharides with different degrees of polymerization were acquired. By comparing with authentic standard substances, along with further confirmation by FTIR, MS and NMR, structures of the purified neoagaro-oligosaccharides were identified as neoagarobiose (NA2), neoagaroteraose (NA4), neoagarohexaose (NA6), neoagarooctaose (NA8), neoagaro-decaose (NA10) and neoagarododecaose (NA12) with purities of more than 97.0%. The present study established a method for the preparation of various neoagaro-oligosaccharides that may be of great significance for further study of their bioactivities.

Volatiles from three genome sequenced fungi from the genusAspergillus

The volatiles emitted by agar plate cultures of three genome sequenced fungal strains from the genusAspergilluswere analysed by GC–MS. All three strains produced terpenes for which a biosynthetic relationship is discussed. The obtained data were also correlated to genetic information about the encoded terpene synthases for each strain. Besides terpenes, a series of aromatic compounds and volatiles derived from fatty acid and branched amino acid metabolism were identified. Some of these compounds have not been described as fungal metabolites before. For the compound ethyl (E)-hept-4-enoate known from cantaloupe a structural revision to the Z stereoisomer is proposed. Ethyl (Z)-hept-4-enoate also occurs inAspergillus clavatusand was identified by synthesis of an authentic standard.

PURIFIKASI SENYAWA POLIFENOL GLUKOSIDA HASIL REAKSI TRANSGLIKOSILASI ENZIMATIK DARI BIAKAN DAN UJI AKTIVITASNYA SEBAGAI ANTIMIKROBA

Polifenol-glukosida disintesis menggunakan CGTase yang berasal dari Nocardia sp. Sintesis polifenol-glukosida dilakukan dengan menggunakan resorsinol sebagai akseptor dan tepung sagu sebagai donor. Penelitian ini bertujuan untuk mensintesis senyawa polifenol-glukosida secara enzimatik menggunakan CGTase dari biakan Nocardia sp,menguji aktivitasnya sebagai senyawa antimikroba dan untuk mengetahui pengaruh senyawa polifenol-glukosida terhadap kerusakan morfologi sel dari biakan Bacillus subtilis. Polifenol–glukosida hasil reaksi transfer dimurnikan menggunakan kolom kromatografi yang berisi matriks oktadesil silica dan menggunakan eluen asam formatdalam methanol (40-90%). Produk yang sudah terpisah ditunjukkan sebagai noda tunggal pada plat kromatografi lapis tipis dengan nilai Rf mendekati nilai Rf standar arbutin. Nilai Rf dari produk transfer tersebut adalah sebesar 0,84 dan nilai Rf standar arbutin adalah sebesar 0.85. Polifenol-glukosida hasil sintesis menunjukkan aktivitasantimikroba terhadap biakan Bacillus subtilis dan Escherichia coli. Kata kunci : polifenol-glukosida, CGT-ase, Nocardia sp., Bacillus subtilis dan Escherichia coli AbstractPolyphenol-glucoside was synthesized by using CGTase derived from Nocardia sp. Synthesis polyphenol-glucoside of was done by using resorcinol as the acceptor and starch sago as the donor. This study aims to synthesized polyphenol-glucoside enzymatically using CGTase derived from Nocardia sp and to assay it’s activity as antimicrobial compound and to determine effect of polyphenol-glucoside on morphological damaging of Bacillus subtilis cells. The synthesized polyphenols-glucoside by transfer reaction was purified through column chromatography containing octadecyl silica matrix that was eluted with formic acid in methanol (40-90%). The separated product was demonstrated by single spot appearance on thin-layer chromatography plate with Rf value that was closed to standard of arbutin Rf. The Rf value of this transfer product was 0.84 while Rf value of arbutin as authentic standard was 0.85. The synthesized polyphenol-glucosie exhibited antimicrobial activity against Bacillus subtilis and Escherichia coli. Key words : Polyphenol-glucoside, CGT-ase, Nocardia sp., Bacillus subtilis and Escherichia coli.

Identification of Angiotensin I-converting enzyme Inhibitory Activities from traditional Mongolian fermented milk products

Several angiotensen-converting enzyme (ACE) inhibitory peptites have been detected in milk products. There are many traditional milk products in Mongolia. For this study, some Mongolian milk products were collected, and the ACE inhibitory activities of these samples were tested; an active fraction was found in aaruul made from mare’s milk. After purification by dialysis and HPLC, the active fractions were isolated. The molecular weight of the active component was 362.05 M, as determined by mass spectrometry. An authentic standard was used to determine the IC50 value of the inhibitory activity. From 5’-GMP is not much higher than that of the active peptide in sour milk and some flavonoids. However, this is the first report that shows that 5’ –GMP inhibits ACE activity. These results will provide useful information for the development of hypertension therapy agents.DOI: http://dx.doi.org/10.5564/mjc.v12i0.175 Mongolian Journal of Chemistry Vol.12 2011: 65-68

Identification and functional characterization of a sesquiterpene synthase gene from Eleutherococcus trifoliatus

In the present study, one sesquiterpene synthase gene in Eleutherococcus trifoliatus was identified and characterized. Full-length cDNA was obtained from stems. It contained an open reading frame of 1671 bp (EtCop) with a predicted molecular mass of 64.5 kDa. The amino acid sequence of EtCop contained the common terpene synthase family motifs RR(x)8W, RxR and DDxxD. The recombinant protein from Escherichia coli was incubated with farnesyl diphosphate in order to identify the function of EtCop. The product of EtCop could be identified as an α-copaene by means of gas chromatography-mass spectrometry analysis and comparison with an authentic standard.

Formation of C19 11-hydroxysteroids by porcine Leydig cells

In a previous study, we reported the presence of 11β-hydroxyandrostenedione and 11β-hydroxytestosterone in testicular vein blood from mature male pigs. Since C19 steroids with an oxygen function at C11 have not been recorded as products of steroid biosynthesis in normal mammalian testes, we have examined their possible production in purified preparations of porcine Leydig cells. Both androstenedione and cortisol were added as substrates in studies using cell incubations of Leydig cells from mature boars (> 8 months old). Steroids were recovered from media by solid-phase extraction and separated by reversed-phase high performance liquid chromatography. Peaks corresponding to retention times of authentic standard steroids were seen for both 11β-hydroxyandrostenedione and 11β-hydroxytestosterone from each substrate. Generally, lesser amounts of C19 11-oxosteroids were noted also. Definitive confirmation was made by gas chromatography – mass spectrometry for 11β-hydroxyandrostenedione in the media.Key words: 11β-hydroxylation, androgens, Leydig cells, porcine, testis.