Synthetic engineering of a new biocatalyst encapsulating [NiFe]-hydrogenases for enhanced hydrogen production

Hydrogenases are microbial metalloenzymes capable of catalyzing the reversible interconversion between molecular hydrogen and protons with high efficiency, and have great potential in the development of new electrocatalysts for renewable...</jats:p

Reprogramming bacterial protein organelles as a nanoreactor for hydrogen production

Compartmentalization is a ubiquitous building principle in cells, which permits segregation of biological elements and reactions. The carboxysome is a specialized bacterial organelle that encapsulates enzymes into a virus-like protein shell and plays essential roles in photosynthetic carbon fixation. The naturally designed architecture, semi-permeability, and catalytic improvement of carboxysomes have inspired rational design and engineering of new nanomaterials to incorporate desired enzymes into the protein shell for enhanced catalytic performance. Here, we build large, intact carboxysome shells (over 90 nm in diameter) in the industrial microorganism Escherichia coli by expressing a set of carboxysome protein-encoding genes. We develop strategies for enzyme activation, shell self-assembly, and cargo encapsulation to construct a robust nanoreactor that incorporates catalytically active [FeFe]-hydrogenases and functional partners within the empty shell for the production of hydrogen. We show that shell encapsulation and the internal microenvironment of the new catalyst facilitate hydrogen production of the encapsulated oxygen-sensitive hydrogenases. The study provides insights into the assembly and formation of carboxysomes and paves the way for engineering carboxysome shell-based nanoreactors to recruit specific enzymes for diverse catalytic reactions

RAP-PCR fingerprinting reveals time-dependent expression of development-related genes following differentiation process of Bacillus thuringiensis

Gene expression profiles are important data to reveal gene functions putatively involved in crucial biological processes. RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) and specifically primed reverse transcription PCR (RT-PCR) were combined to screen differentially expressed genes following development of a commercial Bacillus thuringiensis (Bt) subsp. kurstaki strain 8010 (serotype 3a3b). Six differentially expressed transcripts (RAP1 to RAP6) were obtained. The RAP1 encoded a putative triple helix repeat-containing collagen or an exosporium protein H related to spore pathogenicity. The RAP2 was homologous to a ClpX protease and an ATP-dependent protease La (LonB) likely acted as virulence factors. The RAP3 was homologous to a beta subunit of propionyl-CoA carboxylase (PCC) enzyme (PCCB) required for the development of Myxococcus xanthus. The RAP4 had homology to a quinone oxidoreductase involved in electron transport and ATP formation. The RAP5 showed significant homology to a uridine kinase (UDK) mediated phosphorylation of uridine, azauridine. The RAP6 shared high sequence identity with 3-methyl-2-oxobutanoate-hydroxymethyltransferase (MOHMT) (EC 2.1.2.11) [also known as ketopantoate hydroxymethyltransferase (KPHMT) or PanB] involved in the operation of the tricarboxylic acid cycle. The findings described here would help to elucidate the molecular mechanisms underlying the differentiation process of Bt and unravel novel pathogenic genes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Dominant Contribution of South Asia Monsoon to External Moisture for Extreme Precipitation Events in Northern Tibetan Plateau

Numerous previous studies have pointed out that the South Asia monsoon (SAM) contributes most moisture to the southern Tibetan Plateau, whilst the moisture over the Northern Tibetan Plateau (NTP) is supplied by the westerlies, but the moisture sources for extreme precipitation events remain unclear. In this study, the tracking of external moisture sources was performed on ten extreme precipitation events over each of six target subregions of the NTP during the summer of 2010–2018. We found that the SAM provided most of the external moisture for extreme precipitation events in the NTP, except for the largest contribution from East Asia to extreme precipitation in the easternmost subregion. The moisture carried by westerly winds is the second foreign source over the western NTP. In addition, more than 40% of the NTP extreme precipitation events occurred under the synergy of weak westerlies and enhanced SAM, and these events have a longer duration than others. Thus, SAM plays a key role in moisture transport for the extreme precipitation events over the NTP, even though its contribution to the climatological moisture is not significant

Dominant Contribution of South Asia Monsoon to External Moisture for Extreme Precipitation Events in Northern Tibetan Plateau

Numerous previous studies have pointed out that the South Asia monsoon (SAM) contributes most moisture to the southern Tibetan Plateau, whilst the moisture over the Northern Tibetan Plateau (NTP) is supplied by the westerlies, but the moisture sources for extreme precipitation events remain unclear. In this study, the tracking of external moisture sources was performed on ten extreme precipitation events over each of six target subregions of the NTP during the summer of 2010&ndash;2018. We found that the SAM provided most of the external moisture for extreme precipitation events in the NTP, except for the largest contribution from East Asia to extreme precipitation in the easternmost subregion. The moisture carried by westerly winds is the second foreign source over the western NTP. In addition, more than 40% of the NTP extreme precipitation events occurred under the synergy of weak westerlies and enhanced SAM, and these events have a longer duration than others. Thus, SAM plays a key role in moisture transport for the extreme precipitation events over the NTP, even though its contribution to the climatological moisture is not significant

Origin of Warm SST Bias over the Atlantic Cold Tongue in the Coupled Climate Model FGOALS-g2

Most of the coupled models contain a strong warm bias in sea surface temperature (SST) over the Atlantic Cold Tongue (ACT) region (10&deg; S&ndash;3&deg; N, 20&deg; W&ndash;10&deg; E) during June&ndash;August (JJA) and September&ndash;November (SON). In this study, the origins of the ACT SST bias and their relative contributions to the bias are explored by conducting a set of sensitivity experiments, which are based on an ocean-ice model, and by ignoring the nonlinear effects of each origin. The origins for the warm bias over the ACT in the coupled climate model during JJA are estimated as follows: westerly wind bias along the equator (5&deg; S&ndash;5&deg; N) during March&ndash;May (MAM; contributes approximately 32.6% of the warm bias), northerly bias over the southern tropical Atlantic (25&deg; S&ndash;3&deg; N, 40&deg; W&ndash;20&deg; E) during MAM and JJA (21.4%), bias in the surface specific humidity and surface air temperature (11.9%), and downward shortwave radiation bias (6.5%). The origins of the ACT bias during SON are as follows: northerly bias over the southern tropical Atlantic during SON (31.2%), bias in the surface specific humidity and surface air temperature (27.9%), downward shortwave radiation bias (17.4%), and zonal wind bias (13.4%). Note that these contribution ratios of these origins may be model-dependent. In addition, the local and non-local effects of the zonal wind bias are explored explicitly, while those of all the other biases are examined implicitly. Therefore, a better-performing atmospheric component is crucial when simulating zonal winds during MAM along the equator (5&deg; S&ndash;5&deg; N) and meridional winds during MAM, JJA, and SON over the southern tropical Atlantic, which will alleviate the warm bias over the ACT region in the coupled climate model

Characterization of cry1Cb3 and cry1Fb7 from Bacillus thuringiensis subsp. galleriae

Two cry1-type genes encoding insecticidal crystal proteins (ICPs) were detected by PCR-RFLP and cloned from Bacillus thuringiensis subsp. galleriae 87. The nucleotide sequences were deposited in GenBank with accession numbers EU679501 and EU679502, and designated as cry1Fb7 and cry1Cb3 respectively by B. thuringiensis Delta- Endotoxin Nomenclature Committee. cry1Cb3 shared 99% homology with other cry1Cb genes. The existence of two additional stop codons indicated cry1Cb3 was a silent gene. The cry1Cb3 was 3531 bp with 38.98% G+C content and its first open reading frame (ORF) encoded a protein of 213 amino acid residues with a calculated molecular weight of 23.8 kDa and a predicted pI value of 4.63. Five amino acid sequence blocks (block 1, block 2, block 3, block 4 and block 5) were found in Cry1Cb3. Translation of cry1Fb7 revealed an ORF of 3525 bp with 39.12% G+C content and a protein with a calculated molecular weight of 133.2 kDa and a predicted pI value of 5.18. Cry1Fb7 had five amino acid sequence blocks (blocks 1, 2, 3, 4 and 5) and three domains (I, II and III), which consisted of 218 residues (Leu34 to Ala252), 197 residues (Thr257 to Asp454), and 138 residues (Ile464 to Glu600), respectively

Characterization of Microorganisms from Protaetia brevitarsis Larva Frass

Decomposers play an important role in the biogeochemical cycle. Protaetia brevitarsis larvae (PBLs) can transform wastes into frass rich in humic acid (HA) and microorganisms, which may increase the disease resistance of plants and promote plant growth. Beyond HA, the microorganisms may also contribute to the biostimulant activity. To address this hypothesis, we investigated the potential microbial community in the PBL frass samples and elucidated their functions of disease resistance and plant growth promotion. High-throughput sequencing analysis of four PBL-relevant samples showed that their frass can influence the microbial community of the surrounding environment. Further analysis showed that there were many microorganisms beneficial to agriculture, such as Bacillus. Therefore, culturable Bacillus microbes were isolated from frass, and 16S rDNA gene analysis showed that Bacillus subtilis was the dominant species. In addition, some Bacillus microorganisms isolated from the PBL frass had antibacterial activities against pathogenic fungi. The plant growth promotion pot experiment also proved that some strains promote plant growth. In conclusion, this study demonstrated that the microorganisms in the PBL frass are conducive to colonizing the surrounding organic matrix, which will help beneficial microbes to increase the disease resistance of plants and promote plant growth

Towards Sustainable Green Adjuvants for Microbial Pesticides: Recent Progress, Upcoming Challenges, and Future Perspectives

Microbial pesticides can be significantly improved by adjuvants. At present, microbial pesticide formulations are mainly wettable powders and suspension concentrations, which are usually produced with adjuvants such as surfactants, carriers, protective agents, and nutritional adjuvants. Surfactants can improve the tension between liquid pesticides and crop surfaces, resulting in stronger permeability and wettability of the formulations. Carriers are inert components of loaded or diluted pesticides, which can control the release of active components at appropriate times. Protective agents are able to help microorganisms to resist in adverse environments. Nutritional adjuvants are used to provide nutrients for microorganisms in microbial pesticides. Most of the adjuvants used in microbial pesticides still refer to those of chemical pesticides. However, some adjuvants may have harmful effects on non-target organisms and ecological environments. Herein, in order to promote research and improvement of microbial pesticides, the types of microbial pesticide formulations were briefly reviewed, and research progress of adjuvants and their applications in microbial pesticides were highlighted, the challenges and the future perspectives towards sustainable green adjuvants of microbial pesticides were also discussed in this review