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Poly-β-hydroxybutyrate (PHB) is a biodegradable polymer, synthesized as carbon and energy reserve by bacteria and archaea. To the best of our knowledge, this is the first report on PHB production by a rare actinomycete species, Rhodococcus pyridinivorans BSRT1-1. Response surface methodology (RSM) employing central composite design, was applied to enhance PHB production in a flask scale. A maximum yield of 3.6 ± 0.5 g/L in biomass and 43.1 ± 0.5 wt% of dry cell weight (DCW) of PHB were obtained when using RSM optimized medium, which was improved the production of biomass and PHB content by 2.5 and 2.3-fold, respectively. The optimized medium was applied to upscale PHB production in a 10 L stirred-tank bioreactor, maximum biomass of 5.2 ± 0.5 g/L, and PHB content of 46.8 ± 2 wt% DCW were achieved. Furthermore, the FTIR and 1 H NMR results confirmed the polymer as PHB. DSC and TGA analysis results revealed the melting, glass transition, and thermal decomposition temperature of 171.8, 4.03, and 288 °C, respectively. In conclusion, RSM can be a promising technique to improve PHB production by a newly isolated strain of R. pyridinivorans BSRT1-1 and the properties of produced PHB possessed similar properties compared to commercial PHB.

The synthesis of bioplastic from marine microbes has a great attendance in the realm of biotechnological applications for sustainable eco-management. This study aims to isolate novel strains of poly-β-hydroxybutyrate (PHB)-producing bacteria from the mangrove rhizosphere, Red Sea, Saudi Arabia, and to characterize the extracted polymer. The efficient marine bacterial isolates were identified by the phylogenetic analysis of the 16S rRNA genes as Tamlana crocina, Bacillus aquimaris, Erythrobacter aquimaris, and Halomonas halophila. The optimization of PHB accumulation by E. aquimaris was achieved at 120 h, pH 8.0, 35 °C, and 2% NaCl, using glucose and peptone as the best carbon and nitrogen sources at a C:N ratio of 9.2:1. The characterization of the extracted biopolymer by Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), and Gas chromatography-mass spectrometry (GC-MS) proves the presence of hydroxyl, methyl, methylene, methine, and ester carbonyl groups, as well as derivative products of butanoic acid, that confirmed the structure of the polymer as PHB. This is the first report on E. aquimaris as a PHB producer, which promoted the hypothesis that marine rhizospheric bacteria were a new area of research for the production of biopolymers of commercial value.

Gamma-hydroxybutyrate (GHB; or sodium oxybate) is an endogenous GHB-/gamma-aminobutyric acid B receptor agonist. It is approved for application in narcolepsy and has been proposed for the potential treatment of Alzheimer's disease, Parkinson's disease, fibromyalgia, and depression, all of which involve neuro-immunological processes. Tryptophan catabolites (TRYCATs), the cortisol-awakening response (CAR), and brain-derived neurotrophic factor (BDNF) have been suggested as peripheral biomarkers of neuropsychiatric disorders. GHB has been shown to induce a delayed reduction of T helper and natural killer cell counts and alter basal cortisol levels, but GHB's effects on TRYCATs, CAR, and BDNF are unknown. Therefore, TRYCAT and BDNF serum levels, as well as CAR and the affective state (Positive and Negative Affect Schedule [PANAS]) were measured in the morning after a single nocturnal dose of GHB (50 mg/kg body weight) in 20 healthy male volunteers in a placebo-controlled, balanced, randomized, double-blind, cross-over design. In the morning after nocturnal GHB administration, the TRYCATs indolelactic acid, kynurenine, kynurenic acid, 3-hydroxykynurenine, and quinolinic acid; the 3-hydroxykynurenine to kynurenic acid ratio; and the CAR were significantly reduced (P < 0.05-0.001, Benjamini-Hochberg corrected). The quinolinic acid to kynurenic acid ratio was reduced by trend. Serotonin, tryptophan, and BDNF levels, as well as PANAS scores in the morning, remained unchanged after a nocturnal GHB challenge. GHB has post-acute effects on peripheral biomarkers of neuropsychiatric disorders, which might be a model to explain some of its therapeutic effects in disorders involving neuro-immunological pathologies. This study was registered at ClinicalTrials.gov as NCT02342366.

Catastrophic global accumulation of non-biodegradable plastic has led to efforts for production of alternative eco-friendly biopolymer. Here, we attempted to produce a biodegradable, cytocompatible and eco-friendly polyhydroxy-butyrate (PHB) from a pigmented Bacillus sp. C1 (2013) (KF626477) through submerged (SmF) and solid-state fermentation (SSF). Under SmF and SSF, 0.60 g l−1 and 1.56 g l−1 of PHB with 0.497 g l−1 of yellow fluorescent pigment (YFP) was produced. Fourier transform infrared (FTIR) absorption bands at 1719–1720 cm−1 indicate the presence of C=O group of PHB. Nuclear magnetic resonance (NMR) exhibited the typical chemical shift patterns of PHB, and crystallinity was confirmed from X-ray diffraction (XRD). The melting temperature (Tm), degradation temperature (Td) and crystallinity (Xc) of extracted PHB were found to be 171 °C, 288 °C and 35%, respectively. FACS (Fluorescence-activated cell sorting) confirmed cytocompatibility of PHB at 400 µg ml−1 in mouse fibroblast line. Moreover, biodegradability and elevated cytocompatibility of the PHB produced through SSF make them highly potential biomaterials to be used as a drug delivery carrier in future.

Histone post-translational modifications are important regulators of chromatin structure and gene expression. Lysine 2-hydroxisobutyrylation sites, discovered by MS and validated by chemical synthesis, are found in active chromatin and associated with male germ cell differentiation. We report the identification of a new type of histone mark, lysine 2-hydroxyisobutyrylation (K hib ), and identify the mark at 63 human and mouse histone K hib sites, including 27 unique lysine sites that are not known to be modified by lysine acetylation (K ac ) and lysine crotonylation (K cr ). This histone mark was initially identified by MS and then validated by chemical and biochemical methods. Histone K hib shows distinct genomic distributions from histone K ac or histone K cr during male germ cell differentiation. Using chromatin immunoprecipitation sequencing, gene expression analysis and immunodetection, we show that in male germ cells, H4K8 hib is associated with active gene transcription in meiotic and post-meiotic cells. In addition, H4K8 ac -associated genes are included in and constitute only a subfraction of H4K8 hib -labeled genes. The histone K hib mark is conserved and widely distributed, has high stoichiometry and induces a large structural change. These findings suggest its critical role on the regulation of chromatin functions.

γHydroxybutyric acid (GHB), a depressant of the central nervous system, is commonly used illegally and in drug-facilitated crimes; therefore, it is crucial to develop reliable and fast methods for detecting GHB. This study uses DFT theory to design and evaluate the performance of electrochemical and colorimetric nanosensors based on fullerene and its forms of doping with boron and zinc for GHB detection. The calculation results (bond length, HOMO-LUMO energy gap, infrared spectra and UV-visible absorption spectra) for C showed very good overlap with experimental results in other literature, indicating the validity of the computational method used in this work. Several analyses (such as electronic structure calculations, adsorption energy evaluation, charge-transfer analysis, NBO, NCI/RDG, ELF, LOL, QTAIM, conductivity, recovery time, and optical response analyses) were performed to investigate the sensor performance. After comparing these results, Boron-Doped C (BC ) was found to be the best candidate for electrochemical sensing of GHB based on conductivity modulation & charge transfer behavior. In contrast, pure C with the largest spectral shift (in the visible range) was introduced as a suitable candidate for colorimetric measurement. Zinc-doped C adsorbs GHB best (based on adsorption properties), making it suitable for GHB removal and adsorption in purification applications. Overall, this computational study makes experimental efforts more targeted by qualitatively assessing sensor performance and reducing trial and error, and provides clear guidance for future experimental validation and development of efficient GHB detection platforms.

Research on the uptake and effects of bioplastics by aquatic organisms is still in its infancy. Here, we aim to advance the field by comparing uptake and effects of microplastic particles (MPP) of a biodegradable bioMPP (polyhydroxybutyrate (PHB)) and petroleum-based MPP (polymethylmethacrylate (PMMA)) in the freshwater amphipod Gammarus fossarum. Ingestion of both MPP in different particle sizes (32–250 µm) occurred after 24 h, with highest ingestion of particles in the range 32–63 µm and almost complete egestion after 64 h. A four-week effect-experiment showed a significant decrease of the assimilation efficiency in amphipods exposed to the petroleum-based MPP from week two onwards. The petroleum-based PMMA affected assimilation efficiency significantly in contrast to the biodegradable PHB, but overall differences in direct comparison of MPP types were small. Both MPP types led to a significantly lower wet weight gain relative to the control treatments. After four weeks, differences between both MPP types and silica, used as a natural particle control, were detected. In summary, these results suggest that both MPP types provoke digestive constraints on the amphipods, which go beyond those of natural non-palatable particles. This highlights the need for more detailed research comparing environmental effects of biodegradable and petroleum-based MPP and testing those against naturally occurring particle loads.