The cadmium tolerance and bioaccumulation mechanism of Tetratostichococcus sp. P1: insight from transcriptomics analysis.

Cadmium (Cd) has become a severe issue in relatively low concentration and attracts expert attention due to its toxicity, accumulation, and biomagnification in living organisms. Cd does not have a biological role and causes serious health issues. Therefore, Cd pollutants should be reduced and removed from the environment. Microalgae have great potential for Cd absorption for waste treatment since they are more environmentally friendly than existing treatment methods and have strong metal sorption selectivity. This study evaluated the tolerance and ability of the microalga Tetratostichococcus sp. P1 to remove Cd ions under acidic conditions and reveal mechanisms based on transcriptomics analysis. The results showed that Tetratostichococcus sp. P1 had a high Cd tolerance that survived under the presence of Cd up to 100 µM, and IC50, the half-maximal inhibitory concentration value, was 57.0 µM, calculated from the change in growth rate based on the chlorophyll content. Long-term Cd exposure affected the algal morphology and photosynthetic pigments of the alga. Tetratostichococcus sp. P1 removed Cd with a maximum uptake of 1.55 mg g-1 dry weight. Transcriptomic analysis revealed the upregulation of the expression of genes related to metal binding, such as metallothionein. Group A, Group B transporters and glutathione, were also found upregulated. While the downregulation of the genes were related to photosynthesis, mitochondria electron transport, ABC-2 transporter, polysaccharide metabolic process, and cell division. This research is the first study on heavy metal bioremediation using Tetratostichococcus sp. P1 and provides a new potential microalga strain for heavy metal removal in wastewater.[Figure: see text]Abbreviations:BP: Biological process; bZIP: Basic Leucine Zipper; CC: Cellular component; ccc1: Ca (II)-sensitive cross complementary 1; Cd: Cadmium; CDF: Cation diffusion facilitator; Chl: Chlorophyll; CTR: Cu TRansporter families; DAGs: Directed acyclic graphs; DEGs: Differentially expressed genes; DVR: Divinyl chlorophyllide, an 8-vinyl-reductase; FPN: FerroportinN; FTIR: Fourier transform infrared; FTR: Fe TRansporter; GO: Gene Ontology; IC50: Growth half maximal inhibitory concentration; ICP: Inductively coupled plasma; MF: molecular function; NRAMPs: Natural resistance-associated aacrophage proteins; OD: Optical density; RPKM: Reads Per Kilobase of Exon Per Million Reads Mapped; VIT1: Vacuolar iron transporter 1 families; ZIPs: Zrt-, Irt-like proteins.

Algal biomass production by phosphorus recovery and recycling from wastewater using amorphous calcium silicate hydrates.

The phosphorous supply crisis is a major challenge for a sustainable society, and the algal industry is not unrelated to this crisis. Recycling phosphorus from sewage wastewater is a potential way to address this issue. We previously developed amorphous calcium silicate hydrates (aCSH) as excellent phosphorus recovery materials. In this study, we designed a phosphorus recovery process using aCSH in a pilot-scale facility connected to a sewage wastewater treatment plant, and demonstrated the production of microalgal biomass using phosphorous-containing aCSH (P_aCSH). As a result, high phosphorous recovery rates (>80%) were obtained throughout the year. The carbohydrate-rich microalga Pseudoneochloris sp. NKY372003 was cultivable with P_aCSH. The biomass and carbohydrate productivity of this microalga with P_aCSH was comparable to that with conventional media. Approximately 94% of the phosphorus in P_aCSH was recycled into the biomass. This study successfully demonstrated the recycling the phosphorus recovered from wastewater for microalgal cultivation by aCSH.

Design of Catalytic Peptides and Proteins Through Rational and Combinatorial Approaches.

This review focuses on recent progress in noncomputational methods to introduce catalytic function into proteins, peptides, and peptide assemblies. We discuss various approaches to creating catalytic activity and classification of noncomputational methods into rational and combinatorial classes. The section on rational design covers recent progress in the development of short peptides and oligomeric peptide assemblies for various natural and unnatural reactions. The section on combinatorial design describes recent advances in the discovery of catalytic peptides. We present the future prospects of these and other new approaches in a broader context, including implications for functional material design.

Evaluation of a Microbial Sensor as a Tool for Antimicrobial Activity Test of Cosmetic Preservatives.

For high-throughput screening of novel cosmetic preservatives, a rapid and simple assay to evaluate the antimicrobial activities should be developed because the conventional agar dilution method is time-consuming and labor-intensive. To address this issue, we evaluated a microbial sensor as a tool for rapid antimicrobial activity testing. The sensor consists of an oxygen electrode and a filter membrane that holds the test microorganisms, Staphylococcus aureus and Candida albicans. The antimicrobial activity of the tested cosmetic preservative was evaluated by measuring the current increases corresponding to the decreases in oxygen consumption in the microbial respiration. The current increases detected by the sensor showed positive correlation to the concentrations of two commercially used preservatives, chlorphenesin and 2-phenoxyethanol. The same tendency was also observed when a model cosmetic product was used as a preservative solvent, indicating the feasibility in practical use. Furthermore, the microbial sensor and microfluidic flow-cell was assembled to achieve sequential measurements. The sensor system presented in this study could be useful in large-scale screening experiments.

Oil accumulation by the oleaginous diatom Fistulifera solaris as revealed by the genome and transcriptome.

Oleaginous photosynthetic organisms such as microalgae are promising sources for biofuel production through the generation of carbon-neutral sustainable energy. However, the metabolic mechanisms driving high-rate lipid production in these oleaginous organisms remain unclear, thus impeding efforts to improve productivity through genetic modifications. We analyzed the genome and transcriptome of the oleaginous diatom Fistulifera solaris JPCC DA0580. Next-generation sequencing technology provided evidence of an allodiploid genome structure, suggesting unorthodox molecular evolutionary and genetic regulatory systems for reinforcing metabolic efficiencies. Although major metabolic pathways were shared with nonoleaginous diatoms, transcriptome analysis revealed unique expression patterns, such as concomitant upregulation of fatty acid/triacylglycerol biosynthesis and fatty acid degradation (ß-oxidation) in concert with ATP production. This peculiar pattern of gene expression may account for the simultaneous growth and oil accumulation phenotype and may inspire novel biofuel production technology based on this oleaginous microalga.

Profiling of polar lipids in marine oleaginous diatom Fistulifera solaris JPCC DA0580: prediction of the potential mechanism for eicosapentaenoic acid-incorporation into triacylglycerol.

The marine oleaginous diatom Fistulifera solaris JPCC DA0580 is a candidate for biodiesel production because of its high lipid productivity. However, the substantial eicosapentaenoic acid (EPA) content in this strain would affect the biodiesel quality. On the other hand, EPA is also known as the essential health supplement for humans. EPAs are mainly incorporated into glycerolipids in the microalgal cell instead of the presence as free fatty acids. Therefore, the understanding of the EPA biosynthesis including the incorporation of the EPA into glycerolipids especially triacylglycerol (TAG) is fundamental for regulating EPA content for different purposes. In this study, in order to identify the biosynthesis pathway for the EPA-containing TAG species, a lipidomic characterization of the EPA-enriched polar lipids was performed by using direct infusion electrospray ionization (ESI)-Q-TRAP-MS and MS/MS analyses. The determination of the fatty acid positional distribution showed that the sn-2 position of all the chloroplast lipids and part of phosphatidylcholine (PC) species was occupied by C16 fatty acids. This result suggested the critical role of the chloroplast on the lipid synthesis in F. solaris. Furthermore, the exclusive presence of C18 fatty acids in PC highly indicated the biosynthesis of EPA on PC. Finally, the PC-based acyl-editing and head group exchange processes were proposed to be essential for the incorporation of EPA into TAG and chloroplast lipids.

Effect of the protein and oil contents on calcium utilization in the diets of female Fischer rats that were fed by three different feeding methods.

We studied the effects of varying the protein and oil contents in the diet and three different feeding methods on the utilization of dietary calcium (Ca) in female Fischer rats. The experimental diets were based on the AIN-76 diet. Rats were fed one of nine experimental diets containing different levels of protein and oil. The experimental diets contained 10, 20 or 40% of protein (milk casein) and 5, 10 or 20% of soybean oil. The three meal feeding methods were ad libitum feeding, pair feeding and adjustable feeding. The experimental diets that were given by prepared feeding were supplemented with a mineral and vitamin solution. The effects of the protein and oil contents in the diet were analyzed by two-way ANOVA. Among rats that were fed ad libitum, the oil content in the diet affected the degree of mineral and vitamin intake. Among the rats fed ad libitum, the oil content in the diet had a significant effect on the level of Ca intake, although it did not have a significant effect on the level of energy intake. For pair feeding, the feeding volume was limited in each group; therefore, there was a significant difference in energy intake and there was no significant difference in Ca intake among each diet group. For adjustable feeding, there was considerable mineral and vitamin intake, which effected the reduction of feeding volume depending on the oil volume in the diet. There were no significant differences in the energy, Ca and other mineral and vitamin intakes among the nine groups that were fed using adjustable feeding. In analyzing two-way ANOVA, in which the parameters were the contents of protein and oil in the experimental diets, there were differences in Ca utilization among rats that were fed using the three feeding methods. This result was shown to reflect on the difference as energy, mineral including Ca, and vitamin intake. However, the protein content in the diet had a significant effect on urinary Ca excretion in all three feeding methods. In addition, it was clear that the intake of protein and oil affected kidney calcification in all three feeding methods. The AIN Experimental Diet Committee reported that kidney calcification was found among rats that were fed the AIN-76 diet and that one of the causes of kidney calcification was the Ca/P ratio in this diet. The protein and oil contents in the diets had significant effects on the degree of kidney calcification among rats that were fed by pair feeding or adjustable feeding. The results of this study suggest that the protein and oil contents in the diet play an important role in kidney calcification.

[Evaluation of low-dose FP therapy as adjuvant therapy for gastric cancer].

In the present study, we demonstrate the result of low-dose FP treatment as an adjuvant therapy for 30 patients of stage II or more progressive gastric cancer. 5-FU and CDDP were injected intravenously for 10 days from day 1 through day 5, and day 8 through 12 for 2 weeks at a dose of 250 mg/body and 10 mg/body, or for 14 days at a dose of 250 mg/m2/day and 5 mg/m2/day, respectively. Patients were excluded if they received less than 80% of the respective doses in a course of treatment by the protocol. This constituted a course of chemotherapy, which was repeated every 4 weeks. Grade 3 neutropenia was observed in one case. Other toxicities were anorexia, nausea, weight loss, diarrhea, general fatigue and elevation of serum creatinine, but they were not so severe. The two-year survival rate was 100% in cur A cases, 85% in cur B, and 0% in cur C. The median survival time of the cur C patients was 10 months. These results indicate that low-dose FP therapy is safe and recommendable for cur A and cur B patients. However, other treatment methods such as sequential chemotherapy are needed for cur C gastric cancer patients.