Search

Fournew polyketide synthase–nonribosomal peptide synthetase(PKS–NRPS) hybrid metabolites, pericoannosin A (1), with an unusual hexahydro-1H-isochromen-5-isobutylpyrrolidin-2-oneskeleton, and three cytochalasans, periconiasins D–F (2–4), were isolated from the endophyticfungus Periconiasp. F-31. Their structures and absoluteconfigurations were elucidated through extensive spectroscopic analyses,calculated ECD, and single-crystal X-ray diffraction (Cu Kα).A possible biogenetic pathway is proposed. Compounds 1and 4showed anti-HIV activity with IC50s of 69.6 and 29.2 μM, respectively. [ABSTRACT FROM AUTHOR]

Men who have sex with men (MSM) make up the majority of new human immunodeficiency virus (HIV) diagnoses among young people in China. Understanding HIV transmission dynamics among the MSM population is, therefore, crucial for the control and prevention of HIV infections, especially for some newly reported genotypes of HIV. This study presents a metapopulation model considering the impact of pre-exposure prophylaxis (PrEP) to investigate the geographical spread of a hypothetically new genotype of HIV among MSM in Guangdong, China. We use multiple data sources to construct this model to characterize the behavioural dynamics underlying the spread of HIV within and between 21 prefecturelevel cities (i.e. Guangzhou, Shenzhen, Foshan, etc.) in Guangdong province: the online social network via a gay social networking app, the offline human mobility network via the Baidu mobility website, and self-reported sexual behaviours among MSM. Results show that PrEP initiation exponentially delays the occurrence of the virus for the rest of the cities transmitted from the initial outbreak city; hubs on the movement network, such as Guangzhou, Shenzhen, and Foshan are at a higher risk of 'earliest' exposure to the new HIV genotype; most cities acquire the virus directly from the initial outbreak city while others acquire the virus from cities that are not initial outbreak locations and have relatively high betweenness centralities, such as Guangzhou, Shenzhen and Shantou. This study provides insights in predicting the geographical spread of a new genotype of HIV among an MSM population from different regions and assessing the importance of prefecture-level cities in the control and prevention of HIV in Guangdong province. [ABSTRACT FROM AUTHOR]

Prenylated flavonoids are attractive specialized metabolites with a wide range of biological activities and are distributed in several plant families. The prenylation catalyzed by prenyltransferases represents a Friedel-Crafts alkylation of the flavonoid skeleton in the biosynthesis of natural prenylated flavonoids and contributes to the structural diversity and biological activities of these compounds. To date, all identified plant flavonoid prenyltransferases (FPTs) have been identified in Leguminosae. In the present study two new FPTs, Morus alba isoliquiritigenin 3'-dimethylallyltransferase (MaIDT) and Cudrania tricuspidata isoliquiritigenin 3'-dimethylallyltransferase (CtIDT), were identified from moraceous plants M. alba and C. tricuspidata, respectively. MaIDT and CtIDT shared low levels of homology with the leguminous FPTs. MaIDT and CtIDT are predicted to be membrane-bound proteins with predicted transit peptides, seven transmembrane regions, and conserved functional domains that are similar to other homogentisate prenyltransferases. Recombinant MaIDT and CtIDT were able to regioselectively introduce dimethylallyl diphosphate into the A ring of three flavonoids with different skeleton types (chalcones, isoflavones, and flavones). Phylogenetic analysis revealed thatMaIDT and CtIDT are distantly related to their homologs in Leguminosae, which suggests that FPTs in Moraceae and Leguminosae might have evolved independently. MaIDT and CtIDT represent the first two non-Leguminosae FPTs to be identified in plants and could thus lead to the identification of additional evolutionarily varied FPTs in other non-Leguminosae plants and could elucidate the biosyntheses of prenylated flavonoids in various plants. Furthermore, MaIDT and CtIDT might be used for regiospecific prenylation of flavonoids to produce bioactive compounds for potential therapeutic applications due to their high efficiency and catalytic promiscuity. [ABSTRACT FROM AUTHOR]

Purpose: We induced neural stem cells (NSCs) to neurons by olfactory ensheathing cell (OEC) conditioned medium and characterized their electrophysiological properties after neuronal differentiation. Methods: Fetal NSCs and OECs were cultured from embryonic day 14 SD rats and the conditioned medium was collected and stored at -20°C when the cell number was up to 80% of the culture flasks. The experiment groups were divided into a control group (cultured with DMEM/F12 without FBS) and an OECs induction group (cultured with OEC conditioned medium and DMEM/F12 without FBS). Immunocytochemistry staining was carried out to identify the neurons derived from NSCs and their electrophysiological properties were characterized after neuronal differentiation using a patch-clamp technique. Results: The NSCs divided rapidly in the expansion medium, forming small proliferating spheres after 7 days. The OECs induction group presented an evident neuron-like type 7 days after adding OEC conditioned medium, and the nestin immunochemistry staining was positive. The electrophysiological characterization showed that the derived neurons presented a transient inward sodium current and slow outward potassium current under proper electric stimulus, which were blocked by tetrodotoxin (TTX) and tetraethylammonium (TEA). Conclusion: OEC conditioned medium can induce NSCs to form neurons, and electrophysiological characterization demonstrated that the derived neurons presented active electrophysiological properties which are essential for nervous excitation. [ABSTRACT FROM AUTHOR]