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Dihydroorotase (DHOase) is the third enzyme in the six enzymatic reaction steps of the endogenous pyrimidine nucleotide de novo biosynthesis pathway, which is a metabolic pathway conserved in both bacteria and eukaryotes. However, research on the biological function of DHOase in plant pathogenic fungi is very limited. In this study, we identified and named MoPyr4, a homologous protein of Saccharomyces cerevisiae DHOase Ura4, in the rice blast fungus Magnaporthe oryzae and investigated its ability to regulate fungal growth, pathogenicity, and autophagy. Deletion of MoPYR4 led to defects in growth, conidiation, appressorium formation, the transfer and degradation of glycogen and lipid droplets, appressorium turgor accumulation, and invasive hypha expansion in M. oryzae, which eventually resulted in weakened fungal pathogenicity. Long-term replenishment of exogenous uridine-5'-phosphate (UMP) can effectively restore the phenotype and virulence of the ΔMopyr4 mutant. Further study revealed that MoPyr4 also participated in the regulation of the Pmk1-MAPK signaling pathway, co-localized with peroxisomes for the oxidative stress response, and was involved in the regulation of the Osm1-MAPK signaling pathway in response to hyperosmotic stress. In addition, MoPyr4 interacted with MoAtg5, the core protein involved in autophagy, and positively regulated autophagic degradation. Taken together, our results suggested that MoPyr4 for UMP biosynthesis was crucial for the development and pathogenicity of M. oryzae. We also revealed that MoPyr4 played an essential role in the external stress response and pathogenic mechanism through participation in the Pmk1-MAPK signaling pathway, peroxisome-related oxidative stress response mechanism, the Osm1-MAPK signaling pathway and the autophagy pathway. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) with a d10-configuration containing metal cations offer interesting photoluminescent properties and hence can be employed as sensors to detect various classes of analytes. Moreover, due to their tuneable pore size they can be employed as adsorbents for various species. Herein, a new d10-configuration Cd(II)-based CP with composition {[Cd(bip)4(H2O)2]n·2NO3} (1) (bip = 3,5-bis(1-imidazol)pyridine) has been synthesized and characterized. Single-crystal X-ray analysis reveals that the Cd(II) center adopts octahedral geometry that is satisfied by four N atoms from the four bip linkers and two aqua ligands, and the resultant CP displays sql topology with the point symbol of (44·62). The CP offers prospective application as a photoluminescent sensor for dichromate anions with a limit of detection of 1.28 ppm and a Stern–Volmer constant (KSV) of 1.51 × 105. Furthermore, CP 1 was employed as an efficient adsorbent for dichromate ions, reaching an equilibrium adsorption capacity of 389.82 mg g−1 within 80 min. The effects of temperature, pH and concentration of dichromate were further investigated, which revealed that CP 1 displays the best adsorption at 30 °C and pH 4 with a dichromate concentration of 200 mg L−1. The possible adsorption mechanism has been proposed with the aid of Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Objective To analyze the transmission of HIV-1 infections newly found in Luzhou city, Sichuan Province in 2021, and to investigate the risk factors and characteristics of HIV-1 transmission network, so as to provide data for the prevention and control of AIDS epidemic in Luzhou. Methods The blood samples and demographic information of 363 newly reported HIV-1 infections in Luzhou in 2021 were collected. The HIV-1 pol gene sequence was amplified by nested PCR, and the virus subtype and transmissible drug resistance were analyzed according to the pol gene sequence. The molecular network was constructed based on the optimal gene distance (d=1.5%) and the characteristics of molecular transmission network and its influencing factors were analyzed. Results A total of 346 valid sequences were obtained, including 113 cases of CRF07_BC subtype (32.66%), 107 cases of CRF01_AE subtype (30.92%), 99 cases of CRF08_BC subtype (28.61%), 18 cases of CRF105_0108 subtype (5.20%), and 9 cases of other subtypes (2.60%). The rate of transmitted drug resistance of HIV-1 was 15.03% (52/346), and dual drug resistance was detected in 4 samples. A total of 34 molecular clusters were formed, and the number of cases in the clusters ranged from 2 to 25, with 148 individuals (42.77%) included in the transmission network under the optimal genetic distance threshold (1.5%). There were significant differences in age, education level, infection route, genotype, and registered residence registration (P<0.05). Logistic regression found that education level and registered residence were the influencing factors of network access. Conclusion The newly reported HIV -1 infection in Luzhou city shows diversity of virus genes. CRF01_AE, CRF07_BC, and CRF08_ BC subtype have become the main subtype of epidemic virus strains, and molecular transmission network should be established for long-term monitoring in this region to take targeted measures to block its further transmission. [ABSTRACT FROM AUTHOR]

Magnaporthe oryzae is a pathogenic fungus that seriously harms rice production. Phosphatases and carbon metabolism play crucial roles in the growth and development of eukaryotes. However, it remains unclear how serine/threonine phosphatases regulate the catabolism of triglycerides, a major form of stored lipids. In this study, we identified a serine/threonine protein phosphatase regulatory subunit, Smek1, which is required for the growth, conidiation, and virulence of M. oryzae. Deletion of SMEK1 led to defects in the utilization of lipids, arabinose, glycerol, and ethanol. In glucose medium, the expression of genes involved in lipolysis, long‐chain fatty acid degradation, β‐oxidation, and the glyoxylate cycle increased in the Δsmek1 mutant, which is consistent with ΔcreA in which a carbon catabolite repressor CREA was deleted. In lipid medium, the expression of genes involved in long‐chain fatty acid degradation, β‐oxidation, the glyoxylate cycle, and utilization of arabinose, ethanol, or glycerol decreased in the Δsmek1 mutant, which is consistent with Δcrf1 in which a transcription activator CRF1 required for carbon metabolism was deleted. Lipase activity, however, increased in the Δsmek1 mutant in both glucose and lipid media. Moreover, Smek1 directly interacted with CreA and Crf1, and dephosphorylated CreA and Crf1 in vivo. The phosphatase Smek1 is therefore a dual‐function regulator of the lipid and carbohydrate metabolism, and controls fungal development and virulence by coordinating the functions of CreA and Crf1 in carbon catabolite repression (CCR) and derepression (CCDR). [ABSTRACT FROM AUTHOR]