Sucrose nonfermenting-related protein kinase 1 (SnRK1) is one of the critical serine/threonine protein kinases. It commonly mediates plant growth and development, cross-talks with metabolism ...processes and physiological responses to biotic or abiotic stresses. It plays a key role in distributing carbohydrates and sugar signal transporting. In the present study, eight SnRK1 coding genes were identified in sorghum (Sorghum bicolor L.) via sequences alignment, with three for α subunits (SnRK1α1 to SnRK1α3), three for β (SnRK1β1 to SnRK1β3), and one for both γ (SnRK1γ) and βγ (SnRK1βγ). These eight corresponding genes located on five chromosomes (Chr) of Chr1–3, Chr7, and Chr9 and presented collinearities to SnRK1s from maize and rice, exhibiting highly conserved domains within the same subunits from the three kinds of cereals. Expression results via qRT-PCR showed that different coding genes of SnRK1s in sorghum possessed similar expression patterns except for SnRK1α3 with a low expression level in grains and SnRK1β2 with a relatively high expression level in inflorescences. Results of subcellular localization in sorghum leaf protoplast showed that SnRK1α1/α2/α3/γ mainly located on organelles, while the rest four of SnRK1β1/β2/β3/βγ located on both membranes and some organelles. Besides, three combinations were discovered among eight SnRK1 subunits in sorghum through yeast two hybrid, including α1-β2-βγ, α2-β3-γ, and α3-β3-γ. These results provide informative references for the following functional dissection of SnRK1 subunits in sorghum.
Summary
Based on 16S rRNA gene analyses, the same bacterial operational taxonomic units (OTUs) are common to both the Arctic and Antarctic oceans, supporting the concept ‘everything is everywhere’. ...However, whether the same OTUs from both poles have identical genomes, i.e. whether ‘everything is still everywhere’ at the genomic level has not yet been examined systematically. Here, we isolated, sequenced and compared the genomes of 45 culturable marine bacteria belonging to three genera of Salinibacterium, Psychrobacter and Pseudoalteromonas from both polar oceans. The bacterial strains with identical 16S rRNA genes were common to both poles in every genus, and four identical genomes were detected in the genus Salinibacterium from the Arctic region. However, no identical genomes were observed from opposite poles in this study. Our data, therefore, suggest that ‘everything is not everywhere’ at the genomic level. The divergence time between bacteria is hypothesized to exert a strong impact on the bacterial biogeography at the genomic level. The geographical isolation between poles was observed for recently diverged, highly similar genomes, but not for moderately similar genomes. This study thus improves our understanding of the factors affecting the genomic‐level biogeography of marine microorganisms isolated from distant locations.
Alginate, which is mainly produced by brown algae and decomposed by heterotrophic bacteria, is an important marine organic carbon source. The genus
contains diverse forms of heterotrophic bacteria ...that are widely distributed in marine environments and are an important group in alginate degradation. In this review, the diversity of alginate-degrading
is introduced, and the characteristics of
alginate lyases, including their sequences, enzymatic properties, structures, and catalytic mechanisms, and the synergistic effect of
alginate lyases on alginate degradation are introduced. The acquisition of the alginate degradation capacity and the alginate utilization pathways of
are also introduced. This paper provides a comprehensive overview of alginate degradation by
which will contribute to the understanding of the degradation and recycling of marine algal polysaccharides driven by marine bacteria.
This paper extends the impedance-source (Z-source) inverters concept to the transformer-based Z-source (trans-Z-source) inverters. The original Z-source inverter (ZSI) employs an impedance network of ...two inductors and two capacitors connected in a special arrangement to interface the dc source and the inverter bridge. It has buck and boost function that cannot be achieved by traditional voltage-source inverters and current-source inverters. In the proposed four trans-Z-source inverters, all the impedance networks consist of a transformer and one capacitor. While maintaining the main features of the previously presented Z-source network, the new networks exhibit some unique advantages, such as the increased voltage gain and reduced voltage stress in the voltage-fed trans-ZSIs and the expanded motoring operation range in the current-fed trans-ZSIs, when the turns ratio of the transformer windings is over 1. Simulation and experimental results of the voltage-fed and the current-fed trans-ZSIs are provided to verify the analysis.
Histone acetylation plays critical roles in chromatin remodeling, DNA repair, and epigenetic regulation of gene expression, but the underlying mechanisms are unclear. Proteasomes usually catalyze ...ATP- and polyubiquitin-dependent proteolysis. Here, we show that the proteasomes containing the activator PA200 catalyze the polyubiquitin-independent degradation of histones. Most proteasomes in mammalian testes (“spermatoproteasomes”) contain a spermatid/sperm-specific α subunit α4 s/PSMA8 and/or the catalytic β subunits of immunoproteasomes in addition to PA200. Deletion of PA200 in mice abolishes acetylation-dependent degradation of somatic core histones during DNA double-strand breaks and delays core histone disappearance in elongated spermatids. Purified PA200 greatly promotes ATP-independent proteasomal degradation of the acetylated core histones, but not polyubiquitinated proteins. Furthermore, acetylation on histones is required for their binding to the bromodomain-like regions in PA200 and its yeast ortholog, Blm10. Thus, PA200/Blm10 specifically targets the core histones for acetylation-mediated degradation by proteasomes, providing mechanisms by which acetylation regulates histone degradation, DNA repair, and spermatogenesis.
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•Most proteasomes in mammalian testes are “spermatoproteasomes” that contain PA200•Deletion of PA200 in mice delays core histone disappearance in elongated spermatids•PA200/Blm10 promotes degradation of acetyl-histones during somatic DNA damage•Binding of histones to bromodomain-like regions in PA200/Blm10 depends on acetylation
Specialized proteasomes containing the protein PA2000/BLm10 catalyze the degradation of acetylated—rather than ubiquitinated—core histones during spermatogenesis and DNA damage repair.
•Different microbes in coastal seawater had distinct ecological roles in alginate metabolism process.•The main active degraders were a few genera from Gammaproteobacteria.•The scavenging strains were ...mainly from family Rhodobacteraceae.•Interaction of degrader and scavenging strains had no significant effect on the alginate degradation rate.
The degradation of high molecular weight organic matter (HMWOM) is a core process of oceanic carbon cycle, which is determined by the activity of microbial communities harboring hundreds of different species. Illustrating the active microbes and their interactions during HMWOM processing can provide key information for revealing the relationship between community composition and its ecological functions. In this study, the genomic and transcriptional responses of microbial communities to the availability of alginate, an abundant HMWOM in coastal ecosystem, were elucidated. The main degraders transcribing alginate lyase (Aly) genes came from genera Alteromonas, Psychrosphaera and Colwellia. Meanwhile, some strains, mainly from the Rhodobacteraceae family, did not transcribe Aly gene but could utilize monosaccharides to grow. The co-culture experiment showed that the activity of Aly-producing strain could promote the growth of Aly-non-producing strain when alginate was the sole carbon source. Interestingly, this interaction did not reduce the alginate degradation rate, possibly due to the easily degradable nature of alginate. This study can improve our understanding of the relationship between microbial community activity and alginate metabolism function as well as further manipulation of microbial community structure for alginate processing.
Antarctica is covered by multiple larger glaciers with diverse extreme conditions. Microorganisms in Antarctic regions are primarily responsible for diverse biogeochemical processes. The identity and ...functionality of microorganisms from polar glaciers are defined. However, little is known about microbial communities from the high elevation glaciers. The Union Glacier, located in the inland of West Antarctica at 79°S, is a challenging environment for life to survive due to the high irradiance and low temperatures. Here, soil and rock samples were obtained from three high mountains (Rossman Cove, Charles Peak, and Elephant Head) adjacent to the Union Glacier. Using metagenomic analyses, the functional microbial ecosystem was analyzed through the reconstruction of carbon, nitrogen and sulfur metabolic pathways. A low biomass but diverse microbial community was found. Although archaea were detected, bacteria were dominant. Taxa responsible for carbon fixation were comprised of photoautotrophs (Cyanobacteria) and chemoautotrophs (mainly Alphaproteobacterial clades:
Bradyrhizobium
,
Sphingopyxis
, and
Nitrobacter
). The main nitrogen fixation taxa were
Halothece
(Cyanobacteria),
Methyloversatilis
, and
Leptothrix
(Betaproteobacteria). Diverse sulfide-oxidizing and sulfate-reducing bacteria, fermenters, denitrifying microbes, methanogens, and methane oxidizers were also found. Putative producers provide organic carbon and nitrogen for the growth of other heterotrophic microbes. In the biogeochemical pathways, assimilation and mineralization of organic compounds were the dominant processes. Besides, a range of metabolic pathways and genes related to high irradiance, low temperature and other stress adaptations were detected, which indicate that the microbial communities had adapted to and could survive in this harsh environment. These results provide a detailed perspective of the microbial functional ecology of the Union Glacier area and improve our understanding of linkages between microbial communities and biogeochemical cycling in high Antarctic ecosystems.
A novel Gram-negative, rod-shaped, aerobic, oxidase-positive and catalase-negative bacterium, designated strain SM1970
T
, was isolated from a seawater sample collected from the Mariana Trench. ...Strain SM1970
T
grew at 15-37
o
C and with 1–5% (w/v) NaCl. It hydrolyzed colloidal chitin, agar and casein but did not reduce nitrate to nitrite. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1970
T
formed a distinct lineage close to the genus
Catenovulum
within the family
Alteromonadaceae
, sharing the highest sequence similarity (93.6%) with type strain of
Catenovulum maritimum
but < 93.0% sequence similarity with those of other known species in the class
Gammaproteobacteria.
The major fatty acids of strain SM1970
T
were summed feature 3 (C
16: 1
ω
7
c
and/or C
16: 1
ω
6
c
), C
16: 0
and summed feature 8 (C
18: 1
ω
7
c
and/or C
18: 1
ω
6
c
). The major polar lipids of the strain included phosphatidylethanolamine and phosphatidylglycerol and its main respiratory quinone was ubiquinone 8. The draft genome of strain SM1970
T
consisted of 77 scaffolds and was 4,172,146 bp in length, containing a complete set of genes for chitin degradation. The average amino acid identity (AAI) values between SM1970
T
and type strains of known
Catenovulum
species were 56.6–57.1% while the percentage of conserved proteins (POCP) values between them were 28.5–31.5%. The genomic DNA G + C content of strain SM1970
T
was 40.1 mol%. On the basis of the polyphasic analysis, strain SM1970
T
is considered to represent a novel species in a novel genus of the family
Alteromonadaceae
, for which the name
Marinifaba aquimaris
is proposed with the type strain being SM1970
T
(= MCCC 1K04323
T
= KCTC 72844
T
).
Extracellular enzymes, initiating the degradation of organic macromolecules, are important functional components of marine ecosystems. Measuring
in situ
seawater extracellular enzyme activity (EEA) ...can provide fundamental information for understanding the biogeochemical cycling of organic matter in the ocean. Here we investigate the patterns of EEA and the major factors affecting the seawater EEA of Chinese marginal seas. The geographic distribution of EEA along a latitudinal transect was examined and found to be associated with dissolved organic carbon. Compared with offshore waters, inshore waters had higher enzyme activity. All the tested substrates were hydrolyzed at different rates and phosphatase, β-glucosidase and protease contributed greatly to summed hydrolysis rates. For any particular enzyme activity, the contribution of dissolved to total EEA was strongly heterogenous between stations. Comparisons of hydrolysis rates of the polymers and their corresponding oligomers suggest that molecule size does not necessarily limit the turnover of marine organic matter. In addition, several typical enzyme-producing clades, such as Bacteroidetes, Planctomycetes, Chloroflexi,
Roseobacter
,
Alteromonas
, and
Pseudoalteromonas
, were detected in the
in situ
environments. These enzyme-producing clades may be responsible for the production of different enzymes. Overall, each enzyme was found to flexibly respond to environmental conditions and were linked to microbial community composition. It is likely that this activity will profoundly affect organic matter cycling in the Chinese marginal seas.
Alginate, mainly derived from brown algae, is an important carbon source that can support the growth of marine microorganisms in the Arctic and Antarctic regions. However, there is a lack of ...systematic investigation and comparison of alginate utilization pathways in culturable bacteria from both polar regions. In this study, 88 strains were isolated from the Arctic and Antarctic regions, of which 60 strains could grow in the medium with alginate as the sole carbon source. These alginate-utilizing strains belong to 9 genera of the phyla
and
. The genomes of 26 alginate-utilizing strains were sequenced and genomic analyses showed that they all contain the gene clusters related to alginate utilization. The alginate transport systems of
differ from those of
and there may be unique transport systems among different genera of
. The biogeographic distribution pattern of alginate utilization genes was further investigated. The alginate utilization genes are found to cluster according to bacterial taxonomy rather than geographic location, indicating that the alginate utilization genes do not evolve independently in both polar regions. This study systematically illustrates the alginate utilization pathways in culturable bacteria from the Arctic and Antarctic regions, shedding light into the distribution and evolution of alginate utilization pathways in polar bacteria.
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