Polyploidization Increases the Lipid Content and Improves the Nutritional Quality of Rice

Plant polyploidization is frequently associated with changes in nutrient contents. However, the possible contribution of metabolites to this change has not been investigated by characterizing the metabolite contents of diploid and tetraploid forms of rice (Oryza sativa L.). We compared the metabolites of a group of diploid–tetraploid japonica brown rice and a group of diploid–tetraploid indica brown rice based on liquid chromatography–tandem mass spectrometry. In total, 401 metabolites were identified; of these, between the two diploid–tetraploid groups, 180 showed opposite expression trends, but 221 showed the same trends (147 higher abundance vs. 74 lower abundance). Hierarchical cluster analysis of differential metabolites between diploid and tetraploid species showed a clear grouping pattern, in which the expression abundance of lipids, amino acids and derivatives, and phenolic acids increased in tetraploids. Further analysis revealed that the lipids in tetraploid rice increased significantly, especially unsaturated fatty acids and phospholipids. This study provides further basis for understanding the changes in rice nutritional quality following polyploidization and may serve as a new theoretical reference for breeding eutrophic or functional rice varieties via polyploidization.

Improving the Plasmid Stability by a Hok/Sok System for L-Homoserine Production in Escherichia Coli

Background: The production of bioactive compounds using microbial hosts is considered a safe, cost competitive and scalable approach. However, the efficient engineering of cell factories with well stability, such as for the production of L-aspartate family amino acids and derivatives, remains an outstanding challenge.Results: In the work, the toxin/antitoxin system and genome modification strategy were used to construct a stable Escherichia coli strain for L-homoserine production. The metabolic engineering strategies were focused on the enhancement of precursors for L-homoserine synthesis, reinforcement of the NADPH generation and efflux transporters using CRISPR-Cas9 system at the genome level. To improve the plasmid stability, two strategies were explored, including construction of the aspartate-auxotrophic and hok/sok systems. Constructing the auxotrophic complementation system to maintain plasmid stability was failed herein. The plasmid stability was improved by introducing the hok/sok system, resulting in 6.1 g/L (shake flask) and 44.4 g/L (5 L fermenter) L-homoserine production of the final engineered strain SHL19 without antibiotics addition. Moreover, the hok/sok system was also used to improve the plasmid stability for ectoine production, resulting in 36.7% and 46.5% higher titer of ectoine at shake flask and 5L fermenter without antibiotics addition, respectively. Conclusion: This work provides valuable strategies to improve plasmid stability for producing L-aspartate family amino acids and derivatives and eliminate environmental concerns associated with the application of antibiotics.

Effects of various artificial agarwood-induction techniques on the metabolome of Aquilaria sinensis

Background Agarwood is a highly sought-after resinous wood for uses in medicine, incense, and perfume production. To overcome challenges associated with agarwood production in Aquilaria sinensis, several artificial agarwood-induction treatments have been developed. However, the effects of these techniques on the metabolome of the treated wood samples are unknown. Therefore, the present study was conducted to evaluate the effects of four treatments: fire drill treatment (F), fire drill + brine treatment (FS), cold drill treatment (D) and cold drill + brine treatment (DS)) on ethanol-extracted oil content and metabolome profiles of treated wood samples from A. sinensis. Results The ethanol-extracted oil content obtained from the four treatments differed significantly (F < D < DS < FS). A total of 712 metabolites composed mostly of alkaloids, amino acids and derivatives, flavonoids, lipids, phenolic acids, organic acids, nucleotides and derivatives, and terpenoids were detected. In pairwise comparisons, 302, 155, 271 and 363 differentially accumulated metabolites (DAM) were detected in F_vs_FS, D_vs_DS, F_vs_D and FS_vs_DS, respectively. The DAMs were enriched in flavonoid/flavone and flavonol biosynthesis, sesquiterpenoid and triterpenoid biosynthesis. Generally, addition of brine to either fire or cold drill treatments reduced the abundance of most of the metabolites. Conclusion The results from this study offer valuable insights into synthetically-induced agarwood production in A. sinensis.

SLC36 family of proton-coupled amino acid transporters in GtoPdb v.2021.3

Members of the SLC36 family of proton-coupled amino acid transporters are involved in membrane transport of amino acids and derivatives. The four transporters show variable tissue expression patterns and are expressed in various cell types at the plasma-membrane and in intracellular organelles. PAT1 is expressed at the luminal surface of the small intestine and absorbs amino acids and derivatives [3]. In lysosomes, PAT1 functions as an efflux mechanism for amino acids produced during intralysosomal proteolysis [2, 18]. PAT2 is expressed at the apical membrane of the renal proximal tubule [6] and at the plasma-membrane in brown/beige adipocytes [20]. PAT1 and PAT4 are involved in regulation of the mTORC1 pathway [11]. More comprehensive lists of substrates can be found within the reviews under Further Reading and in the references [3].

Study On Parameter Optimization of 3D Bioprinting of Hybrid Bio-Inks

Used mainly for manufacturing operative tissue structures to replace damaged ones, Three-dimensional (3D) Bioprinting is a burgeoning area of medical science with enormous potential. Since the technology is still relatively new, 3D bioprinting heavily relies on the trial-and-error approach for advancement, but the general process currently involves a mixture of various biomaterials in hydrogel form. The quality of the results is affected significantly by the parameters by which the print is made. Even the most seemingly minute details can drastically change the outcome of the print, including temperature, print time, the speed of the occurring print and nozzle diameter, dispensing pressure, and more. The biomaterial used is also of the utmost importance. Based on current results, an ideal biomaterial should include the same or similar chemical, biological, mechanical, and practical properties of the target end structure. It is critical to ascertain the closest parameters available to ensure a quality end resulting print. The proposed studies' goal is to determine and streamline process parameters to the nearest possible degree to optimize the bioprinting process of hybrid bioinks. Using material made from unchanged alginate, alginate with gelatin, and combined amino acids and derivatives with diphenylalanine, the medical properties of each biomaterial were examined, as well as their flow behavior, allowing a certain level of predictability on printing parameters. Printing parameters, as described, are the parameters by which we can predict how well a target structure can be accurately constructed using various bio-inks. Ultimately, the results have indicated that printing parameters primarily hinges on the composition of the hydrogels used and the pressure by which it was distributed. This study also presented a detailed frame of reference to assess amino acids and derivatives with diphenylalanine systematically, which can also be used in other areas of 3D bioprinting.

Pichia pastoris and the Recombinant Human Heterodimeric Amino Acid Transporter 4F2hc-LAT1: From Clone Selection to Pure Protein

Heterodimeric amino acid transporters (HATs) are protein complexes composed of two subunits, a heavy and a light subunit belonging to the solute carrier (SLC) families SLC3 and SLC7. HATs transport amino acids and derivatives thereof across the plasma membrane. The human HAT 4F2hc-LAT1 is composed of the type-II membrane N-glycoprotein 4F2hc (SLC3A2) and the L-type amino acid transporter LAT1 (SLC7A5). 4F2hc-LAT1 is medically relevant, and its dysfunction and overexpression are associated with autism and tumor progression. Here, we provide a general applicable protocol on how to screen for the best membrane transport protein-expressing clone in terms of protein amount and function using Pichia pastoris as expression host. Furthermore, we describe an overexpression and purification procedure for the production of the HAT 4F2hc-LAT1. The isolated heterodimeric complex is pure, correctly assembled, stable, binds the substrate L-leucine, and is thus properly folded. Therefore, this Pichia pastoris-derived recombinant human 4F2hc-LAT1 sample can be used for downstream biochemical and biophysical characterizations.

Metabolome Profiling of Eight Chinese Yam (Dioscorea polystachya Turcz.) Varieties Reveals Metabolite Diversity and Variety Specific Uses

The Chinese yam (Dioscorea polystachya Turcz.) is an underutilized orphan tuber crop. However, in China it has been used in traditional medicine and food for centuries due to the presence of high starch, protein, fiber, and biologically active compounds. Knowledge on the metabolomic profiles of Chinese yam varieties is needed to explore the underutilized metabolites and variety specific uses. Here, the metabolome of eight Chinese yam varieties that are cultivated in different Chinese regions was profiled. A total of 431 metabolites belonging to different biochemical classes was detected. The majority of detected metabolites were classified as amino acids and derivatives. The different yam varieties offer unique uses; e.g., Hebei Ma Yam, Henan Huai Yam, and Henan Wild Yam were the most metabolically enriched and suitable as food and medicine. Yams from Hubei region had comparable nutritional profiles, which is most probably due to their geographical origin. Specifically, Henan Wild Yam had the highest concentrations of diosgenin, vitamins, and polysaccharides. Overall, this study presents a metabolome reference for D. polystachya varieties.

Primary Metabolite Profile Changes in Coffea spp. Promoted by Single and Combined Exposure to Drought and Elevated CO2 Concentration

Climate change scenarios pose major threats to many crops worldwide, including coffee. We explored the primary metabolite responses in two Coffea genotypes, C. canephora cv. Conilon Clone 153 and C. arabica cv. Icatu, grown at normal (aCO2) or elevated (eCO2) CO2 concentrations of 380 or 700 ppm, respectively, under well-watered (WW), moderate (MWD), or severe (SWD) water deficit conditions, in order to assess coffee responses to drought and how eCO2 can influence such responses. Primary metabolites were analyzed with a gas chromatography time-of-flight mass spectrometry metabolomics platform (GC-TOF-MS). A total of 48 primary metabolites were identified in both genotypes (23 amino acids and derivatives, 10 organic acids, 11 sugars, and 4 other metabolites), with differences recorded in both genotypes. Increased metabolite levels were observed in CL153 plants under single and combined conditions of aCO2 and drought (MWD and SWD), as opposed to the observed decreased levels under eCO2 in both drought conditions. In contrast, Icatu showed minor differences under MWD, and increased levels (especially amino acids) only under SWD at both CO2 concentration conditions, although with a tendency towards greater increases under eCO2. Altogether, CL153 demonstrated large impact under MWD, and seemed not to benefit from eCO2 in either MWD and SWD, in contrast with Icatu.

Comparative Metabolic Profiling of Grape Pulp during the Growth Process Reveals Systematic Influences under Root Restriction

The compositions and contents of metabolites in the pulp tissue play critical roles in the fruit quality for table grape. In this study, the effects of root restriction (RR) on the primary and secondary metabolites of pulp tissue at five developmental stages were studied at the metabolomics level, using “Red Alexandria” grape berry (Vitis vinifera L.) as materials. The main results were as follows: 283 metabolites were annotated by using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS); 28 and 16 primary metabolites contents were increased and decreased, and 11 and 19 secondary metabolites contents were increased and decreased, respectively, along the berry development; RR significantly decreased 12 metabolites (four amino acids and derivatives, three organic acids, four flavonoids and one other compound) contents, and improved 40 metabolites (22 amino acids and derivatives, six nucleotides, four carbohydrates, four cofactors, three cinnamic acids and one other compound) accumulation at the different developmental stages. Altogether, our study would be helpful to increase our understanding of grape berry’s responses to RR stress.