Artemisinin: current state and perspectives for biotechnological production of an antimalarial drug

Artemisinin isolated from the aerial parts of Artemisia annua L. is a promising and potent antimalarial drug which has a remarkable activity against chloroquine-resistant and chloroquine-sensitive strains of Plasmodium falciparum, and is useful in treatment of cerebral malaria. Because the low content (0.01–1 %) of artemisinin in A. annua is a limitation to the commercial production of the drug, many research groups have been focusing their researches on enhancing the production of artemisinin in tissue culture or in the whole plant of A. annua. This review mainly focuses on the progresses made in the production of artemisinin from A. annua by biotechnological strategies including in vitro tissue culture, metabolic regulation of artemisinin biosynthesis, genetic engineering, and bioreactor technology.     

Soil Properties and their Spatial Pattern in a Degraded Sandy Grassland under Post-grazing Restoration, Inner Mongolia, Northern China

In this study, we use classical and geostatistical methods to identify characteristics of some selected soil properties including soil particle size distribution, soil organic carbon, total nitrogen, pH and electrical conductivity and their spatial variation in a 5-year recovery degraded sandy grassland after two different grazing intensity disturbance: post-heavy-grazing restoration grassland (HGR) and post-moderately grazing restoration grassland (MGR), respectively, in Horqin steppe, Inner Mongolia, northern China. The objective was to examine effect of grazing intensity on spatial heterogeneity of soil properties. One hundred soil samples were taken from the soil layer 0–15 cm in depth of a grid of 10 m×10 m under each treatment. The results showed that soil fine fractions (very fine sand, 0.1–0.05 mm and silt + clay, <0.05 mm), soil organic carbon and total nitrogen concentrations were significant lower and their coefficients of variation significant higher under the HGR than under the MGR. Geostatistical analysis of soil heterogeneity revealed that soil particle size fractions, organic carbon and total nitrogen showed different degree of spatial dependence with exponential or spherical semivariograms on the scale measured under HGR and MGR. The spatial structured variance account for a large proportion of the sample variance in HGR plot ranging from 88% to 97% for soil particle fractions, organic C and total N, however, except for organic C (88.8%), the structured variance only account for 50% of the sample variance for soil particle fractions and total N in the MGR plot. The ranges of spatial autocorrelation for coarse-fine sand, very fine sand, silt + clay, organic C and total N were 13.7 m, 15.8 m, 15.2 m, 22.2 m and 21.9 m in HGR plot, respectively, and was smaller than in MGR plot with the corresponding distance of 350 m, 144.6 m, 45.7 m, 27.3 m and 30.3 m, respectively. This suggested that overgrazing resulted in an increase in soil heterogeneity. Soil organic C and total N were associated closely with soil particle fractions, and the kriging-interpolated maps showed that the spatial distribution of soil organic C and total N corresponded to the distribution patterns of soil particle fractions, indicating that high degree of spatial heterogeneity in soil properties was linked to the distribution of vegetative and bare sand patches. The results suggested that the degree of soil heterogeneity at field scale can be used as an index for indicating the extent of grassland desertification. Also, the changes in soil heterogeneity may in turn influence vegetative succession and restoration process of degraded sandy grassland ecosystem.     

Genus-Wide Comparative Genomics of Malassezia Delineates Its Phylogeny,Physiology, and Niche Adaptation on Human Skin

Malassezia is a unique lipophilic genus in class Malasseziomycetes in Ustilaginomycotina, (Basidiomycota, fungi) that otherwise consists almost exclusively of plant pathogens. Malassezia are typically isolated from warm-blooded animals, are dominant members of the human skin mycobiome and are associated with common skin disorders. To characterize the genetic basis of the unique phenotypes of Malassezia spp., we sequenced the genomes of all 14 accepted species and used comparative genomics against a broad panel of fungal genomes to comprehensively identify distinct features that define the Malassezia gene repertoire: gene gain and loss; selection signatures; and lineage-specific gene family expansions. Our analysis revealed key gene gain events (64) with a single gene conserved across all Malassezia but absent in all other sequenced Basidiomycota. These likely horizontally transferred genes provide intriguing gain-of-function events and prime candidates to explain the emergence of Malassezia. A larger set of genes (741) were lost, with enrichment for glycosyl hydrolases and carbohydrate metabolism, concordant with adaptation to skin’s carbohydrate-deficient environment. Gene family analysis revealed extensive turnover and underlined the importance of secretory lipases, phospholipases, aspartyl proteases, and other peptidases. Combining genomic analysis with a re-evaluation of culture characteristics, we establish the likely lipid-dependence of all Malassezia. Our phylogenetic analysis sheds new light on the relationship between Malassezia and other members of Ustilaginomycotina, as well as phylogenetic lineages within the genus. Overall, our study provides a unique genomic resource for understanding Malassezia niche-specificity and potential virulence, as well as their abundance and distribution in the environment and on human skin.     

Retinal Arteriolar Morphometry Based on Full Width at Half Maximum Analysis of Spectral-Domain Optical Coherence Tomography Images

Objectives

In this study, we develop a microdensitometry method using full width at half maximum (FWHM) analysis of the retinal vascular structure in a spectral-domain optical coherence tomography (SD-OCT) image and present the application of this method in the morphometry of arteriolar changes during hypertension.

Methods

Two raters using manual and FWHM methods measured retinal vessel outer and lumen diameters in SD-OCT images. Inter-rater reproducibility was measured using coefficients of variation (CV), intraclass correlation coefficient and a Bland-Altman plot. OCT images from forty-three eyes of 43 hypertensive patients and 40 eyes of 40 controls were analyzed using an FWHM approach; wall thickness, wall cross-sectional area (WCSA) and wall to lumen ratio (WLR) were subsequently calculated.

Results

Mean difference in inter-rater agreement ranged from -2.713 to 2.658 μm when using a manual method, and ranged from -0.008 to 0.131 μm when using a FWHM approach. The inter-rater CVs were significantly less for the FWHM approach versus the manual method (P < 0.05). Compared with controls, the wall thickness, WCSA and WLR of retinal arterioles were increased in the hypertensive patients, particular in diabetic hypertensive patients.

Conclusions

The microdensitometry method using a FWHM algorithm markedly improved inter-rater reproducibility of arteriolar morphometric analysis, and SD-OCT may represent a promising noninvasive method for in vivo arteriolar morphometry.     

Antioxidant and antidiabetic activities of mycelial and fruit-body extracts from <Emphasis Type="Italic">Mycoleptodonoides aitchisonii</Emphasis>

Mycoleptodonoides aitchisonii (Berk.) Maas Geest. is a culinary mushroom that is recognized as both a nutritious food and an excellent source of bioactive compounds. The purpose of this study was to investigate the antioxidant and antidiabetic properties of M. aitchisonii (MA) both in vitro and in vivo. Total oxyradical scavenging capacity (TOSC) assays revealed that fruit-body extracts had higher antioxidant capacity than mycelial extracts, 0.9-fold higher as measured by peroxynitrite (PN) scavenging assay, 3.7-fold higher as measured by peroxyl radical (PR) scavenging assay, and 1.6-fold as measured by hydroxyl radical (HR) scavenging assay, respectively. The assay of Akt phosphorylation, which is inhibited by Interleukin 6 (IL-6) in the signal transduction pathway for diabetes, was employed to evaluate the antidiabetic activity. Fruit-body extracts significantly increased Akt phosphorylation according to the fruit-body extract concentration, with a maximum increment of 77% at a concentration of 100 μg/mL compared to 51.4% decrement caused by IL-6, but there was no effect of mycelial extracts. Treatment with 5% MA fruit-body powder and streptozotocin (STZ) decreased the blood sugar level to 233.8 mg/dL in diabetic mice compared to 333.8 mg/dL after treatment with STZ alone. Additionally, MA treatment lowered total cholesterol (TC), triglyceride (TG), and LDL-cholesterol levels, while it increased the HDL-cholesterol level. All these findings indicate that fruit-body of M. aitchisonii has potential utility in preventing various diseases such as disorders of sugar and lipid metabolism.     

Microbial secondary metabolites ameliorate growth, <Emphasis Type="Italic">in planta</Emphasis> contents and lignification in <Emphasis Type="Italic">Withania somnifera</Emphasis> (L.) Dunal

In the present investigation, metabolites of Streptomyces sp. MTN14 and Trichoderma harzianum ThU significantly enhanced biomass yield (3.58 and 3.48 fold respectively) in comparison to the control plants. The secondary metabolites treatments also showed significant augmentation (0.75–2.25 fold) in withanolide A, a plant secondary metabolite. Lignin deposition, total phenolic and flavonoid content in W. somnifera were maximally induced in treatment having T. harzianum metabolites. Also, Trichoderma and Streptomyces metabolites were found much better in invoking in planta contents and antioxidants compared with their live culture treatments. Therefore, identification of new molecular effectors from metabolites of efficient microbes may be used as biopesticide and biofertilizer for commercial production of W. somnifera globally.