During the processes of primary and secondary endosymbiosis, different microalgae evolved to synthesis different storage polysaccharides. In stramenopiles, the main storage polysaccharides are ...β-1,3-glucan, or laminarin, in vacuoles. Currently, laminarin is gaining considerable attention due to its application in the food, cosmetic and pharmaceuticals industries, and also its importance in global biogeochemical cycles (especially in the ocean carbon cycle). In this review, the structures, composition, contents, and bioactivity of laminarin were summarized in different algae. It was shown that the general features of laminarin are species-dependence. Furthermore, the proposed biosynthesis and catabolism pathways of laminarin, functions of key genes, and diel regulation of laminarin were also depicted and comprehensively discussed for the first time. However, the complete pathways, functions of genes, and diel regulatory mechanisms of laminarin require more biomolecular studies. This review provides more useful information and identifies the knowledge gap regarding the future studies of laminarin and its applications.
Macroalgae host various symbionts on their surface, which play a critical role in their growth and development processes. However, there is still incomplete understanding of this epiphytic ...bacteria-host algae interactions. This study comprehensively analysed variation of the epiphytic bacterial communities (EBC) composition of red macroalga Gracilariopsis lemaneiformis at different geographic locations and environmental factors (i.e., nitrogen and phosphorus), which shape the EBC composition of G. lemaneiformis. The composition and structure of EBC were characterized using high throughput sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The results revealed that epiphytic bacteria varied significantly among three different geographic locations in China, i.e., Nan'ao Island (NA), Lianjiang County (LJ), and Nanri Island (NR). Redundancy analysis (RDA) showed that the relative abundance of Bacteroidetes, Firmicutes, Verrucomicrobia, and Epsilonbacteraeota at NR were strongly positively correlated with total nitrogen (TN), total phosphorus (TP), nitrate nitrogen (NO
-N), and dissolved inorganic nitrogen (DIN), but negatively correlated with nitrite nitrogen (NO
-N). The relative abundance of Cyanobacteria at NA and LJ were strongly positively correlated with NO
-N, but negatively correlated with TN, TP, NO
-N, and DIN. Besides, the Mantel test results indicated that the EBC composition was significantly correlated with these environmental factors, which was also confirmed by Spearman correlation analysis. Thus, environmental factors such as NO
-N and DIN play a key role in the community composition of epiphytic bacteria on G. lemaneiformis. This study provides important baseline knowledge on the community composition of epiphytic bacteria on G. lemaneiformis and shows correlation between different epiphytic bacteria and their surrounding environmental factors.
Phaeodactylum tricornutum (Pt) is a critical microbial cell factory to produce a wide spectrum of marketable products including recombinant biopharmaceutical N-glycoproteins. N-glycosylation ...modification of proteins is important for their activity, stability, and half-life, especially some special modifications, such as fucose-modification by fucosyltransferase (FucT). Three PtFucTs were annotated in the genome of P. tricornutum, PtFucT1 was located on the medial/trans-Golgi apparatus and PtFucT2-3 in the plastid stroma. Algal growth, biomass and photosynthesis efficiency were significantly inhibited in a knockout mutant of PtFucT1 (PtFucT1-KO). PtFucT1 played a role in non-core fucose modification of N-glycans. The knockout of PtFucT1 might affect the activity of PtGnTI in the complex and change the complex N-glycan to mannose type N-glycan. The study provided critical information for understanding the mechanism of protein N-glycosylation modification and using microalgae as an alternative ecofriendly cell factory to produce biopharmaceuticals.
Four amphiphilic hybrids based on polyoxovanadate with hydrophobic tails of different quantities and lengths were successfully synthesized. In particular, three crystal structures of the amphiphilic ...hybrids have been confirmed by single crystal XRD and their manner of packing has been investigated to reveal the driving force of the crystal stacking. Furthermore, the morphologies and microstructures of the products were studied using SEM and TEM. Their wettabilities were also measured by the contact angle method. The results indicated that the increase of the single alkyl chain length could be beneficial to the crystal packing. Increasing the quantity of the alkyl chains was detrimental to crystal growth but could lead to smoother and hydrophobic material surfaces.
Crystal structures of polyoxometalate-based amphiphiles with multiple alkyl tails were characterized by single crystal X-ray diffraction to reveal the relationship between morphologies and manner of packing.
To gain further insight into the evolution of mitochondrial genomes (mtDNAs) in Phaeophyceae, the first recorded characterization of an Ishigeophycidae mtDNA from
Ishige okamurae
(Yendo), and only ...the second recorded characterization of a Dictyotophycidae mtDNA from
Dictyopteris divaricata
(Okamura) Okamura are presented in this study. The 35,485 bp
I. okamurae
mtDNA contained 36 protein-coding genes (PCGs), 22 tRNAs, three rRNAs, and four open reading frames (
orfs
), and the 32,021 bp
D. divaricata
mtDNA harbored 35 PCGs, 25 tRNAs, three rRNAs, and three
orfs
. The A + T content in
D. divaricata
(61.69%) was the lowest recorded in sequenced brown algal mtDNAs. The
I. okamurae
mtDNA displayed unique genome features including an elevated start-codon usage bias for GTG, while the organization of
D. divaricata
mtDNA was identical to that of
Dictyota dichotoma
. Phylogenetic analysis based on the amino acid sequence dataset of 35 PCGs indicated that
I. okamurae
(Ishigeophycidae) diverged early from the Fucophycidae–Dictyotophycidae complex, which was confirmed by the comparative analysis of the mitogenome structure. The novel mitogenome data made available by this study have improved our understanding of the evolution, phylogenetics, and genomics of brown algae.
N-glycosylation is an important posttranslational modification in all eukaryotes, but little is known about the N-glycoproteins and N-glycans in microalgae. Here, N-glycoproteomic and N-glycomic ...approaches were used to unveil the N-glycoproteins and N-glycans in the model diatom
. In total, 863 different N-glycopeptides corresponding to 639 N-glycoproteins were identified from
. These N-glycoproteins participated in a variety of important metabolic pathways in
. Twelve proteins participating in the N-glycosylation pathway were identified as N-glycoproteins, indicating that the N-glycosylation of these proteins might be important for the protein N-glycosylation pathway. Subsequently, 69 N-glycans corresponding to 59 N-glycoproteins were identified and classified into high mannose and hybrid type N-glycans. High mannose type N-glycans contained four different classes, such as Man-5, Man-7, Man-9, and Man-10 with a terminal glucose residue. Hybrid type N-glycan harbored Man-4 with a terminal GlcNAc residue. The identification of N-glycosylation on nascent proteins expanded our understanding of this modification at a N-glycoproteomic scale, the analysis of N-glycan structures updated the N-glycan database in microalgae. The results obtained from this study facilitate the elucidation of the precise function of these N-glycoproteins and are beneficial for future designing the microalga to produce the functional humanized biopharmaceutical N-glycoproteins for the clinical therapeutics.
In this work, two heterometallic clusters, namely TiIV4MoV4MoVI2O16(OCH3)16 (1) and TiIV4MoV4O10(OC2H5)14 (C6H5COO)2 (2) are successfully constructed to improve the solar absorption and performance ...of titanium oxo clusters (TOCs). The 1 and 2 structures are determined well by single-crystal X-ray diffraction analysis and found to feature the common presence of Mo–Mo interactions. The solid-state UV–vis absorption studies indicate that these structures exhibit enhanced visible-light absorption and significantly reduced optical band gaps, which should be dominantly attributed to the introduction of electron-rich Mo–Mo pairs as heterometals. This work demonstrates an effective strategy of regulating the light absorption behaviors of TOCs by importing electron-rich heterometals.
ABSTRACT Two-stage harvesting is the main method for performing the mechanized harvesting of peanuts, and the picking device is a core part of the combined harvester in China. In order to solve the ...problem of pod loss caused by the "stacking", "impact" and "throwing up" of peanut plants by a traditional cam-slide spring-finger cylinder picking device, the shovel-finger and cylinder peanut-picking device was developed and used in a picking-up performance test based on the study of peanut-plant strip-picking characteristics. The mathematical model of the mechanism was established by analyzing the structure of the mechanism and the peanut-plant strip-picking characteristics, and the parameters of the mechanism were optimized using the objective function method. The prototype was developed and tested. The experiments in which the prototype was used to collect peanut plants indicated that the phenomenon of peanut plants being stacked and thrown disappeared. Through a response surface analysis and prototype test, the optimal working parameters of the picking device were obtained: the forward speed V was 48.0 m/minute, the rotational speed N was 45.3 r/minute and the ground height H was -18 mm. The peanut-plant picking rate was 98.9% and the fruit loss rate was 2.8% under two different harvesting conditions for which the peanut-plant moisture content was 15~17%.
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