Microsporidian EnP1 alters host cell H2B monoubiquitination and prevents ferroptosis facilitating microsporidia survival.

Microsporidia are intracellular eukaryotic pathogens that pose a substantial threat to immunocompromised hosts. The way these pathogens manipulate host cells during infection remains poorly understood. Using a proximity biotinylation strategy we established that microsporidian EnP1 is a nucleus-targeted effector that modifies the host cell environment. EnP1's translocation to the host nucleus is meditated by nuclear localization signals (NLSs). In the nucleus, EnP1 interacts with host histone H2B. This interaction disrupts H2B monoubiquitination (H2Bub), subsequently impacting p53 expression. Crucially, this inhibition of p53 weakens its control over the downstream target gene SLC7A11, enhancing the host cell's resilience against ferroptosis during microsporidian infection. This favorable condition promotes the proliferation of microsporidia within the host cell. These findings shed light on the molecular mechanisms by which microsporidia modify their host cells to facilitate their survival.

Aspartyl proteases identified as candidate genes of a fiber length QTL, qFLD05, that regulates fiber length in cotton (Gossypium hirsutum L.).

KEY MESSAGE: GhAP genes were identified as the candidates involved in cotton fiber length under the scope of fine mapping a stable fiber length QTL, qFLD05. Moreover, the transcription factor GhWRKY40 positively regulated GhAP3 to decrease fiber length. Fiber length (FL) is an economically important fiber quality trait. Although several genes controlling cotton fiber development have been identified, our understanding of this process remains limited. In this study, an FL QTL (qFLD05) was fine-mapped to a 216.9-kb interval using a secondary F2:3 population derived from the upland hybrid cultivar Ji1518. This mapped genomic segment included 15 coding genes, four of which were annotated as aspartyl proteases (GhAP1-GhAP4). GhAPs were identified as candidates for qFLD05 as the sequence variations in GhAPs were associated with FL deviations in the mapping population, and functional validation of GhAP3 and GhAP4 indicated a longer FL following decreases in their expression levels through virus-induced gene silencing (VIGS). Subsequently, the potential involvement of GhWRKY40 in the regulatory network was revealed: GhWRKY40 positively regulated GhAP3's expression according to transcriptional profiling, VIGS, yeast one-hybrid assays and dual-luciferase experiments. Furthermore, alterations in the expression of the eight previously reported cotton FL-responsive genes from the above three VIGS lines (GhAP3, GhAP4 and GhWRKY40) implied that MYB5_A12 was involved in the GhWRKY40-GhAP network. In short, we unveiled the unprecedented FL regulation roles of GhAPs in cotton, which was possibly further regulated by GhWRKY40. These findings will reveal the genetic basis of FL development associated with qFLD05 and be beneficial for the marker-assisted selection of long-staple cotton.

Host cell manipulation by microsporidia secreted effectors: Insights into intracellular pathogenesis.

Microsporidia are prolific producers of effector molecules, encompassing both proteins and nonproteinaceous effectors, such as toxins, small RNAs, and small peptides. These secreted effectors play a pivotal role in the pathogenicity of microsporidia, enabling them to subvert the host's innate immunity and co-opt metabolic pathways to fuel their own growth and proliferation. However, the genomes of microsporidia, despite falling within the size range of bacteria, exhibit significant reductions in both structural and physiological features, thereby affecting the repertoire of secretory effectors to varying extents. This review focuses on recent advances in understanding how microsporidia modulate host cells through the secretion of effectors, highlighting current challenges and proposed solutions in deciphering the complexities of microsporidial secretory effectors.

Overcoming research challenges: In vitro cultivation of Ameson portunus (Phylum Microsporidia).

Ameson portunus is an intracellular pathogen that infects marine crabs Portunus trituberculatus and Scylla paramamosain, causing significant economic losses. However, research into this important parasite has been limited due to the absence of an in vitro culture system. To address this challenge, we developed an in vitro cultivation model of A. portunus using RK13 cell line in this study. The fluorescent labeling assay indicated a high infection rate (∼60 %) on the first day post-infection and quantitative PCR (qPCR) detection demonstrated successful infection as early as six hours post-inoculation. Fluorescence in situ hybridization (FISH) and qPCR were used for the detection of A. portunus infected cells. The FISH probe we designed allowed detection of A. portunus in infected cells and qPCR assay provided accurate quantification of A. portunus in the samples. Transmission electron microscopy (TEM) images revealed that A. portunus could complete its entire life cycle and produce mature spores in RK13 cells. Additionally, we have identified novel life cycle characteristics during the development of A. portunus in RK 13 cells using TEM. These findings contribute to our understanding of new life cycle pathways of A. portunus. The establishment of an in vitro culture model for A. portunus is critical as it provides a valuable tool for understanding the molecular and immunological events that occur during infection. Furthermore, it will facilitate the development of effective treatment strategies for this intracellular pathogen.

Pharmacokinetics, Bioequivalence, and Safety Evaluation of Two Oral Formulations of Calcium Dobesilate Capsules in Healthy Chinese Volunteers Under Fasting and Fed Conditions.

To determine the pharmacokinetics (PK), safety, and bioequivalence profiles of 0.5-g calcium dobesilate capsules in both fasting and fed states for the test drug and reference drug. A randomized-sequence, single-dose, open-label, 2-period crossover study was conducted in fasted and fed healthy Chinese volunteers (Chinese Clinical Trials Registry identifier: CTR202000268-01). The fasting and fed studies, both involving 24 subjects, were conducted. A single dosage of either the reference or the test preparation was given to each eligible subject in a 1:1 ratio, followed by a 7-day rest interval before the administration of the alternative formulation. After taking the capsules, plasma samples were taken for 48 hours, and using liquid chromatography-tandem mass spectrometry, the calcium dobesilate level was determined. The PK parameters evaluated in the study included the maximum serum concentration (Cmax), area under the plasma concentration-time curve (AUC) from time 0 to the last quantifiable concentration, AUC from time 0 to infinity, half-life, time to Cmax, and terminal elimination rate constant. In addition, the safety evaluation encompassed monitoring fluctuations in vitals (temperature, pulse, and blood pressure) and laboratory tests (urinalysis, hepatic function, blood biochemistry, and hematology), as well as recording the emergence of adverse events (AEs). The geometric mean ratio (GMR) of the test/reference medications was used to assess bioequivalence by determining if the 90% confidence intervals of the GMR fell within the predefined range of 80%-125%. AEs were assessed as safety end points. The study included 48 healthy Chinese volunteers (with n = 24 each for the fasting and the fed conditions), and no subjects dropped out for any reason. The differences in the PK metrics for the test and reference drugs for both conditions were insignificant (P > .05). For bioequivalence, irrespective of whether the food was consumed or not, the range of the 90% confidence intervals of the GMR for Cmax, AUC from time 0 to the last quantifiable concentration, and AUC from time 0 to infinity was between 80% and 125%. In the experiment, no serious AEs were recorded. Our findings revealed that the calcium dobesilate capsules used as the reference and the test drugs were both bioequivalent. Irrespective of whether the healthy Chinese volunteers consumed food or not, the PK and safety profiles were comparable.

An aldehyde dehydrogenase gene, GhALDH7B4_A06, positively regulates fiber strength in upland cotton (Gossypium hirsutum L.).

High fiber strength (FS) premium cotton has significant market demand. Consequently, enhancing FS is a major objective in breeding quality cotton. However, there is a notable lack of known functionally applicable genes that can be targeted for breeding. To address this issue, our study used specific length-amplified fragment sequencing combined with bulk segregant analysis to study FS trait in an F2 population. Subsequently, we integrated these results with previous quantitative trait locus mapping results regarding fiber quality, which used simple sequence repeat markers in F2, F2:3, and recombinant inbred line populations. We identified a stable quantitative trait locus qFSA06 associated with FS located on chromosome A06 (90.74-90.83 Mb). Within this interval, we cloned a gene, GhALDH7B4_A06, which harbored a critical mutation site in coding sequences that is distinct in the two parents of the tested cotton line. In the paternal parent Ji228, the gene is normal and referred to as GhALDH7B4_A06O; however, there is a nonsense mutation in the maternal parent Ji567 that results in premature termination of protein translation, and this gene is designated as truncated GhALDH7B4_A06S. Validation using recombinant inbred lines and gene expression analysis revealed that this mutation site is correlated with cotton FS. Virus-induced gene silencing of GhALDH7B4 in cotton caused significant decreases in FS and fiber micronaire. Conversely, GhALDH7B4_A06O overexpression in Arabidopsis boosted cell wall component contents in the stem. The findings of our study provide a candidate gene for improving cotton fiber quality through molecular breeding.

Evaluation of Ornidazole Tablets Bioequivalence in Chinese Healthy Participants Under Fasted and Fed Conditions Using Pharmacokinetic Parameters.

BACKGROUND AND OBJECTIVE: Ornidazole, the third generation of nitroimidazole derivatives after metronidazole and tinidazole, it exerts both bactericidal and antiprotozoal effects. The purpose of this study was to evaluate the pharmacokinetic and bioequivalence of two ornidazole tablets manufactured by two different manufacturers based on their pharmacokinetic parameters. PATIENTS AND METHODS: Fasted and fed healthy Chinese volunteers participated in a randomized sequence, single-dose, open-label, two-period crossover trial. There were 24 participants in both the fed study and the fasted study. Following a 7-day washout period before receiving the alternative formulation, eligible research participants were randomly assigned (1:1) to receive a single dosage of either the reference formulation or the test formulation. Following tablet administration, plasma samples were obtained over 72 h and analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to evaluate ornidazole contents. maximum plasma concentration (Cmax), time to Cmax (Tmax), the area under the curve (AUC) from t = 0 to infinity (AUC0-∞), AUC from t = 0 to the last quantifiable concentration (AUC0-t), half-life (t1/2), and terminal elimination rate constant (z) were evaluated as pharmacokinetic (PK) parameters. The safety evaluation involved adverse events (AEs) incidence and alterations in laboratory tests (hepatic function, blood biochemistry, hematology, and urinalysis) or vital signs (temperature, pulse, and blood pressure). RESULTS: For the bioequivalence assessment in the fast trial, the prime PK parameters comparison between the reference and test formulation revealed that the GMR (90% CI) values for AUC0-t, Cmax, and AUC0-∞ were 100.97% (99.12-102.85%), 99.88% (90.63-110.08%), and 101.12% (99.17-103.11%), respectively. For the bioequivalence assessment in the fed trial, the key PK parameters comparison between the reference and test formulations revealed that the GMR (90% CI) values for AUC0-t, Cmax, and AUC0-∞ were 103.00% (100.94-105.11%), 101.90% (99.63-104.22%), and 102.99% (100.87-105.16%), respectively. The geometric mean ratios (GMRs) for the primary pharmacokinetic parameters (Cmax, AUC0-72, and AUC0-∞) between the two formulations and the corresponding 90% confidence intervals (CIs) were all within the range of 80.00-125.00% for both the fasting and fed states. Both treatments have comparable safety profiles. CONCLUSION: The bioequivalence and tolerability of ornidazole tablet reference and test formulations were evaluated among healthy Chinese participants under both fasting and fed conditions. The results indicated that both formulations were bioequivalent and generally well tolerated; besides, the interaction between food and drug may affect drug pharmacokinetics. TRIAL REGISTRATION: CTR20212873, registered on 15 November 2021; ChiCTR2300069098, registered on 7 March 2023.