Screening of astaxanthin-overproducing Xanthophyllomyces dendrorhous strains via iterative ARTP mutagenesis and cell sorting by flow cytometry.

Aims: The astaxanthin-producing yeast Xanthophyllomyces dendrorhous is widely used in aquaculture. Due to the production of carotenoid, this yeast shows visible color; however, high-throughput approaches for identification of astaxanthin-overproducing strains remain rare.

Methods And Results: This study verified an effective approach to identify astaxanthin-overproducing mutants of X.

High-level production of nervonic acid in the oleaginous yeast Yarrowia lipolytica by systematic metabolic engineering.

Nervonic acid benefits the treatment of neurological diseases and the health of brain. In this study, we employed the oleaginous yeast Yarrowia lipolytica to overproduce nervonic acid oil by systematic metabolic engineering. First, the production of nervonic acid was dramatically improved by iterative expression of the genes ecoding β-ketoacyl-CoA synthase CgKCS, fatty acid elongase gELOVL6 and desaturase MaOLE2.

Nervonic acid and its sphingolipids: Biological functions and potential food applications.

Nervonic acid, a 24-carbon fatty acid with only one double bond at the 9th carbon (C24:1n-9), is abundant in the human brain, liver, and kidney. It not only functions in free form but also serves as a critical component of sphingolipids which participate in many biological processes such as cell membrane formation, apoptosis, and neurotransmission. Recent studies show that nervonic acid supplementation is not only beneficial to human health but also can improve the many medical conditions such as neurological diseases, cancers, diabetes, obesity, and their complications.

GATA transcription factor WC2 regulates the biosynthesis of astaxanthin in yeast Xanthophyllomyces dendrorhous.

Astaxanthin is a type of carotenoid widely used as powerful antioxidant and colourant in aquaculture and the poultry industry. Production of astaxanthin by yeast Xanthophyllomyces dendrorhous has attracted increasing attention due to high cell density and low requirements of water and land compared to photoautotrophic algae. Currently, the regulatory mechanisms of astaxanthin synthesis in X.

Comprehensive Analysis of CRISPR-Cas9 Editing Outcomes in Yeast .

DNA repair after Cas9 cutting can result in deletions/insertions, genomic rearrangements, and rare nucleotide substitutions. However, most work has only focused on deletions/insertions resulting from repair after CRISPR-Cas9 action. Here, we comprehensively analyzed the editing outcomes induced by CRISPR-Cas9 treatment in yeast by Sanger and Illumina sequencing and identified diverse DNA repair patterns, including DNA deletions, interchromosomal translocations, and on-target nucleotide substitutions (point mutations).

Prevalence and spatial distribution patterns of human echinococcosis at the township level in Sichuan Province, China.

Background: Echinococcosis is a global zoonotic parasitic disease caused by Echinococcus larvae. This disease is highly endemic in Sichuan Province, China. This study investigates the prevalence and spatial distribution characteristics of human echinococcosis at the township level in Sichuan Province, geared towards providing a future reference for the development of precise prevention and control strategies.

Selectable marker recycling in the nonconventional yeast Xanthophyllomyces dendrorhous by transient expression of Cre on a genetically unstable vector.

Selectable marker recycling is a basic technique in bioengineering. However, this technique is usually unavailable in non-model microorganisms. In this study, we proposed a simple and efficient method for selectable marker recycling in the astaxanthin-synthesizing yeast Xanthophyllomyces dendrorhous.

Cell permeability and nuclear DNA staining by propidium iodide in basidiomycetous yeasts.

Non-model yeasts within basidiomycetes have considerable importance in agriculture, industry, and environment, but they are not as well studied as ascomycetous yeasts. Serving as a basic technique, nuclear DNA staining is widely used in physiology, ecology, cell biology, and genetics. However, it is unclear whether the classical nuclear DNA staining method for ascomycetous yeasts is applicable to basidiomycetous yeasts.

A one-step bioprocess for production of high-content fructo-oligosaccharides from inulin by yeast.

Commercial fructo-oligosaccharides (FOS) are predominantly produced from sucrose by transfructosylation process that presents a maximum theoretical yield below 0.60gFOSgSucrose(-1). To obtain high-content FOS, costly purification is generally employed.

Engineering a natural Saccharomyces cerevisiae strain for ethanol production from inulin by consolidated bioprocessing.

Background: The yeast Saccharomyces cerevisiae is an important eukaryotic workhorse in traditional and modern biotechnology. At present, only a few S. cerevisiae strains have been extensively used as engineering hosts.

Starmerella orientalis f.a., sp. nov., an ascomycetous yeast species isolated from flowers.

Four strains of a novel ascomycetous yeast species were isolated from flowers in Iran and China. Phylogenetic analysis of the sequences of the ITS region (including 5.8S rRNA gene) and the LSU rRNA gene D1/D2 domains indicated that these strains belong to the Starmerella clade and show divergence from previously described species in this clade.

Stress Tolerance Variations in Saccharomyces cerevisiae Strains from Diverse Ecological Sources and Geographical Locations.

The budding yeast Saccharomyces cerevisiae is a platform organism for bioethanol production from various feedstocks and robust strains are desirable for efficient fermentation because yeast cells inevitably encounter stressors during the process. Recently, diverse S. cerevisiae lineages were identified, which provided novel resources for understanding stress tolerance variations and related shaping factors in the yeast.

Organisms for biofuel production: natural bioresources and methodologies for improving their biosynthetic potentials.

In order to relieve the pressure of energy supply and environment contamination that humans are facing, there are now intensive worldwide efforts to explore natural bioresources for production of energy storage compounds, such as lipids, alcohols, hydrocarbons, and polysaccharides. Around the world, many plants have been evaluated and developed as feedstock for bioenergy production, among which several crops have successfully achieved industrialization. Microalgae are another group of photosynthetic autotroph of interest due to their superior growth rates, relatively high photosynthetic conversion efficiencies, and vast metabolic capabilities.

Expression of exoinulinase genes in Saccharomyces cerevisiae to improve ethanol production from inulin sources.

To improve inulin utilization and ethanol fermentation, exoinulinase genes from the yeast Kluyveromyces marxianus and the recently identified yeast, Candida kutaonensis, were expressed in Saccharomyces cerevisiae. S. cerevisiae harboring the exoinulinase gene from C.

Improved ethanol fermentation by heterologous endoinulinase and inherent invertase from inulin by Saccharomyces cerevisiae.

It is hypothesized that introduction of an endoinulinase gene into Saccharomyces cerevisiae will improve its inulin utilization and ethanol fermentation through collaboration between the heterologous endoinulinase and the inherent invertase SUC2. The aim of this work was to test the hypothesis by introducing the endoinulinase gene inuA from Aspergillus niger into S. cerevisiae.

Invertase SUC2 Is the key hydrolase for inulin degradation in Saccharomyces cerevisiae.

Specific Saccharomyces cerevisiae strains were recently found to be capable of efficiently utilizing inulin, but genetic mechanisms of inulin hydrolysis in yeast remain unknown. Here we report functional characteristics of invertase SUC2 from strain JZ1C and demonstrate that SUC2 is the key enzyme responsible for inulin metabolism in S. cerevisiae.

Surprisingly diverged populations of Saccharomyces cerevisiae in natural environments remote from human activity.

The budding yeast, Saccharomyces cerevisiae, is a leading system in genetics, genomics and molecular biology and is becoming a powerful tool to illuminate ecological and evolutionary principles. However, little is known of the ecology and population structure of this species in nature. Here, we present a field survey of this yeast at an unprecedented scale and have performed population genetics analysis of Chinese wild isolates with different ecological and geographical origins.

Thermotolerant Kluyveromyces marxianus and Saccharomyces cerevisiae strains representing potentials for bioethanol production from Jerusalem artichoke by consolidated bioprocessing.

Thermotolerant inulin-utilizing yeast strains are desirable for ethanol production from Jerusalem artichoke tubers by consolidated bioprocessing (CBP). To obtain such strains, 21 naturally occurring yeast strains isolated by using an enrichment method and 65 previously isolated Saccharomyces cerevisiae strains were investigated in inulin utilization, extracellular inulinase activity, and ethanol fermentation from inulin and Jerusalem artichoke tuber flour at 40 °C. The strains Kluyveromyces marxianus PT-1 (CGMCC AS2.

Purification and characterization of a novel extracellular inulinase from a new yeast species Candida kutaonensis sp. nov. KRF1(T).

A novel extracellular exoinulinase was purified and characterized from a new yeast strain KRF1(T), and the gene encoding the enzyme was successfully cloned. The enzyme was stable at low pH between 3.0 and 6.

Candida laoshanensis sp. nov. and Candida qingdaonensis sp. nov., anamorphic, ascomycetous yeast species isolated from decayed wood.

During a study of newly isolated yeast strains utilizing d-xylose as sole carbon source, eight strains, isolated from decayed wood, were found to represent two novel anamorphic, ascomycetous yeast species based on sequence analysis of the 26S rDNA D1/D2 domain and internal transcribed spacer region, and phenotypic characterization. The names Candida laoshanensis sp. nov.

[Spatial distribution and elimination of Schistosome japonicum intermediate hosts Oncomelania hupensis in mountainous regions].

Objective: To explore the spatial distribution and elimination of Oncomelania hupensis in mountainous regions.

Methods: Puge County in Tezi township was selected as the study site and the quadratus were placed randomly to investigate snail. The two sods with water were selected as the sites of snail elimination.

Rapid differentiation of phenotypically similar yeast species by single-strand conformation polymorphism analysis of ribosomal DNA.

Single-strand conformation polymorphism (SSCP) analysis of ribosomal DNA (rDNA) was investigated for rapid differentiation of phenotypically similar yeast species. Sensitive tests indicated that some yeast strains with one, most strains with two, and all strains with three or more nucleotide differences in the internal transcribed spacer 1 (ITS1) or ITS2 region could be distinguished by PCR SSCP analysis. The discriminative power of SSCP in yeast species differentiation was demonstrated by comparative studies of representative groups of yeast species from ascomycetes and basidiomycetes, including Saccharomyces species, medically important Candida species, and phylloplane basidiomycetous yeast species.

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants.

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii.

Saccharomyces arboricolus sp. nov., a yeast species from tree bark.

Three ascomycetous yeast strains, H-6(T), ZX-15 and ZX-20, isolated from the bark of two tree species of the family Fagaceae collected from different regions of China, formed unconjugated and persistent asci containing two to four globose ascospores. 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region (including 5.8S rDNA) sequence analysis showed that they were closely related to the currently accepted Saccharomyces species with strong support.