Transcriptome Analysis Reveals the Function of a G-Protein α Subunit Gene in the Growth and Development of Pleurotus eryngii.

Pleurotus eryngii is a commercially important edible fungus with high nutritional and economic value. However, few functional studies have examined key genes affecting the growth and development of P. eryngii. In this study, transformed strains, including over-expression (PeGNAI-OE) and RNA interference (PeGNAI-RNAi) lines, were constructed to elucidate the role of GNAI in P. eryngii growth. GNAI expression was found to affect the mycelial growth and the number of clamp connections. Moreover, the transformed strains were shown to have higher endogenous cAMP levels, thus affecting amylase and laccase activity. Fruiting experiments showed that GNAI expression revealed the formation of P. eryngii primordia and the number of buttons, while transcription analysis identified GNAI gene involvement in the growth and development of P. eryngii. Seven downstream genes regulated by GNAI were differentially expressed in PeGNAI-OE and PeGNAI-RNAi compared to wild type (WT). These genes may be related to mycelial growth and enzyme activity. They were involved in the MAPK signaling pathway, inositol phosphate metabolism, ascorbate, aldarate metabolism, and starch and sucrose metabolism. In summary, GNAI performs different physiological functions in regulating the growth and development of P. eryngii. Importantly, the molecular mechanisms of GNAI regulatory function are relatively complex and need further study.

Fish eDNA detection and its technical optimization: A case study of Acanthopagrus latus.

The development of a standardized eDNA detection process is the primary step in improving the accuracy and efficiency of eDNA detection. In this study, primers and probes with high specificity were selected to identify the COI gene of Acanthopagrus latus. Through experiments on the influence of different water quantities, methods of water sample preservation and water bathing times on the result of eDNA detection, the accuracy of this method for extracted water samples was improved. Specifically, a water bathing time of 6 h provided an optimal eDNA concentration from the water sample. After 6 h, the concentration began to decrease, so 6 h was determined to be the best water bathing time for A. latus. Five water extraction volumes (250 mL, 500 mL, 1 L, 2 L, and 3 L) were tested, and there was a positive correlation between water extraction volume and the DNA concentration in the water sample. Different water sample preservation methods were also compared, and it was found that at ≤7 d, the concentration obtained with the cryopreservation method for different water extraction volumes was higher than that obtained with the ethanol preservation method. In this study, we established and optimized a technical procedure for eDNA-based detection of A. latus in aquatic environments. We hope to apply this method in field investigations and provide a reference for the study of eDNA in other fishes.

Efficient (3S)-Acetoin and (2S,3S)-2,3-Butanediol Production from meso-2,3-Butanediol Using Whole-Cell Biocatalysis.

(3S)-Acetoin and (2S,3S)-2,3-butanediol are important platform chemicals widely applied in the asymmetric synthesis of valuable chiral chemicals. However, their production by fermentative methods is difficult to perform. This study aimed to develop a whole-cell biocatalysis strategy for the production of (3S)-acetoin and (2S,3S)-2,3-butanediol from meso-2,3-butanediol. First, E. coli co-expressing (2R,3R)-2,3-butanediol dehydrogenase, NADH oxidase and Vitreoscilla hemoglobin was developed for (3S)-acetoin production from meso-2,3-butanediol. Maximum (3S)-acetoin concentration of 72.38 g/L with the stereoisomeric purity of 94.65% was achieved at 24 h under optimal conditions. Subsequently, we developed another biocatalyst co-expressing (2S,3S)-2,3-butanediol dehydrogenase and formate dehydrogenase for (2S,3S)-2,3-butanediol production from (3S)-acetoin. Synchronous catalysis together with two biocatalysts afforded 38.41 g/L of (2S,3S)-butanediol with stereoisomeric purity of 98.03% from 40 g/L meso-2,3-butanediol. These results exhibited the potential for (3S)-acetoin and (2S,3S)-butanediol production from meso-2,3-butanediol as a substrate via whole-cell biocatalysis.

Efficient (3R)-Acetoin Production from meso-2,3-Butanediol Using a New Whole-Cell Biocatalyst with Co-Expression of meso-2,3-Butanediol Dehydrogenase, NADH Oxidase, and Vitreoscilla Hemoglobin.

Acetoin (AC) is a volatile platform compound with various potential industrial applications. AC contains two stereoisomeric forms: (3S)-AC and (3R)-AC. Optically pure AC is an important potential intermediate and widely used as a precursor to synthesize novel optically active materials. In this study, chiral (3R)-AC production from meso-2,3-butanediol (meso-2,3-BD) was obtained using recombinant Escherichia coli cells co-expressing meso-2,3-butanediol dehydrogenase (meso-2,3-BDH), NADH oxidase (NOX), and hemoglobin protein (VHB) from Serratia sp. T241, Lactobacillus brevis, and Vitreoscilla, respectively. The new biocatalyst of E. coli/pET-mbdh-nox-vgb was developed and the bioconversion conditions were optimized. Under the optimal conditions, 86.74 g/l of (3R)-AC with the productivity of 3.61 g/l/h and the stereoisomeric purity of 97.89% was achieved from 93.73 g/l meso-2,3-BD using the whole-cell biocatalyst. The yield and productivity were new records for (3R)-AC production. The results exhibit the industrial potential for (3R)-AC production via whole-cell biocatalysis.