An entomopathogenic fungus exploits its host humoral antibacterial immunity to minimize bacterial competition in the hemolymph.

BACKGROUND: The insect hemolymph (blood-equivalent fluid), composed of a large number of hemocytes (blood cells) and a variety of soluble immune effectors, is hostile for pathogens including fungi. In order to survive in the insect hemocoel (body cavity), the entomopathogenic fungus (EPF) has evolved two classical coping strategies, namely evasion and suppression of the host immune reactions. However, it remains unclear whether EPF has other ways of coping with host immunity. RESULTS: In this study, we demonstrated that Metarhizium rileyi (an EPF) infection by injection of blastospores into the hemocoel enhanced the plasma antibacterial activity of cotton bollworm (Helicoverpa armigera), which was partially due to the enhanced expression of antimicrobial peptides (AMPs). The early stage of M. rileyi infection induced the translocation of gut bacteria into the hemocoel, where they were subsequently cleared due to the enhanced plasma antibacterial activity. Further, we showed that the enhanced plasma antibacterial activity and AMP expression were attributable to M. rileyi but not the invasive gut bacteria (opportunistic bacteria). Elevated ecdysone (major steroid hormone in insects) levels in the hemolymph at 48 h post-M. rileyi infection might contribute to the enhanced expression of AMPs. The fungus-elicited AMPs, such as cecropin 3 or lebocin, exhibited potent inhibitory activity against the opportunistic bacteria but not against hyphal bodies. In addition, the opportunistic bacteria competed with hyphal bodies for amino acid nutrients. CONCLUSIONS: M. rileyi infection induced the translocation of gut bacteria, and then the fungi activated and exploited its host humoral antibacterial immunity to eliminate opportunistic bacteria, preventing them from competing for nutrients in the hemolymph. Unlike the classical strategies, EPF utilizes to evade or suppress host immunity, our findings reveal a novel strategy of interaction between EPF and host immunity. Video Abstract.

Renal venous sampling assisted the diagnosis of juxtaglomerular cell tumor: a case report and literature review.

Juxtaglomerular cell tumor (JCT) is an endocrine tumor marked by elevated renin levels and high blood pressure. This case report presents the clinical findings of a 47-year-old woman with a history of recurrent hypokalemia, headaches, hypertension, and increased plasma renin activity (PRA). Dynamic enhanced magnetic resonance imaging (MRI) revealed a small nodule on the upper part of the right kidney. Selective renal venous sampling indicated a higher PRA only in the right upper pole renal vein. The patient underwent surgical removal of the right kidney mass, and the pathology results confirmed the diagnosis of JCT. This case underscores the importance of conducting selective renal venous sampling for accurate JCT diagnosis.

Calcium and integrin-binding protein 1-like interacting with an integrin α-cytoplasmic domain facilitates cellular immunity in Helicoverpa armigera.

Integrins are transmembrane receptor heterodimers composed of α and ß subunits. They are known to mediate extracellular signals to promote cell adhesion and spreading, and are therefore essential for cellular immunity. However, proteins that bind to integrin cytoplasmic domains and mediate intracellular signaling to promote cell adhesion require identification. Calcium and integrin-binding protein 1 (CIB1) that binds to the integrin α-cytoplasmic domain has rarely been examined in insects. In this study, we found that 20-hydroxyecdysone promoted cell phagocytosis and spreading in Helicoverpa armigera. Transcriptomic analyses of hemocytes identified an integrin α gene (HaINTα-PS1) whose expression could be induced by either 20-hydroxyecdysone injection or bead challenge. Isothermal titration calorimetry assays showed that H. armigera CIB1-like (HaCIB1-like) weakly bound to the cytoplasmic domain of HaINTα-PS1 in the presence of calcium. HaINTα-PS1 or HaCIB1-like knockdown inhibited hemocytic encapsulation and phagocytosis, and plasmatocyte spreading. Moreover, HaCIB1-like overexpression in a H. armigera epidermal cell line overexpanded cells and impaired cell phagocytosis. Thus, insect CIB1-like potentially interacted with integrin α-cytoplasmic domain and facilitated cell adhesion. This study enriches our understanding of the molecular mechanism underlying integrin-mediated cellular immunity in insects.

Biological Characteristics and Molecular Mechanism of Procymidone Resistance in Stemphylium eturmiunum From Garlic.

Garlic leaf blight caused by Stemphylium eturmiunum was first reported in Jiangsu Province in China. The dicarboximide fungicide (DCF) procymidone is reported to possess broad-spectrum action in inhibiting filamentous fungi and is widely used to control leaf disease of various plants. Of 41 Stemphylium eturmiunum isolates collected in this study from commercial garlic farms in Pizhou and Dafeng counties of Jiangsu Province, eight isolates were resistant to procymidone. The following three phenotypes were categorized according to in vitro responses to DCFs: sensitive, low resistance to iprodione and procymidone, and high resistance to all iprodione and procymidone. The fitness of all resistant isolates was decreased in accordance with data on mycelial growth, conidiation, and virulence. After treatment with 10 µg/ml of procymidone for 4 h, mycelial intracellular glycerol concentrations of resistant isolates were significantly lower than those of sensitive isolates. Positive cross-resistance was observed between dicarboximides and phenylpyrroles, but there was no cross-resistance between dicarboximides and fluazinam or difenoconazole in the two resistant phenotypes. Nucleotide sequence alignment of two-component histidine kinase genes from sensitive and resistant isolates indicated that amino acid mutations were located at the histidine kinase, adenylyl cyclase, methyl-accepting chemotaxis protein and at the phosphatase domain of the N-terminal region and the response regulator domain of the C-terminal region. To our knowledge, this is the first report of DCF resistance in Stemphylium eturmiunum, and these findings will help establish a rational strategy to manage DCF-resistant populations of Stemphylium eturmiunum in the field.

Xanthones from Swertia mussotii as multitarget-directed antidiabetic agents.

Oxidative stress has been suggested to play a causative role in the development of obesity-induced insulin resistance and type 2 diabetes. Given the antioxidant potency of previously reported xanthones isolated from Swertia mussotii. These natural products were further evaluated against other targets in diabetes, aldose reductase and α-glucosidase, in order to identify novel multitarget-directed antidiabetic agents. Among the 14 xanthones screened, 1,3,7,8-tetrahydroxyxanthone (6), 1,3,5,8-tetrahydroxyxanthone (7), and 2,3,6,8-tetrahydroxyxanthone-7C-(ß-D-glucoside) (12) were confirmed as good antioxidants and α-glucosidase inhibitors. Xanthone 7 was also confirmed as a potent inhibitor of aldose reductase (ALR2). Xanthone 7 was the most active α-glucosidase and ALR2 inhibitor, with IC50 values of 5.2±0.3 µM and 88.6±1.6 nM, respectively, while compound 12 was shown to be the most active antioxidant. Given the overall profile, xanthone 7 is considered to be the most promising multitarget antidiabetic agent, and may have potential for the treatment of both diabetes and diabetic complications.

Xanthones from Swertia mussotii and their α-glycosidase inhibitory activities.

Two new xanthones, 1,8-dihydroxy-3-methoxyxanthone 7-O-[α-L-rhamnopyranosyl(1 → 2)-ß-D-glucopyranoside] (1) and 1,8- dihydroxy-3-methoxyxanthone 7-O-[α-L-rhamnopyranosyl(1 → 3)-α-L-rhamno-pyranosyl (1 → 2)-ß-D-xylopyranoside] (2), together with 26 known xanthones (3-28), were isolated from the aqueous ethanol extract of the traditional Chinese herb Swertia mussotii. Their structures were elucidated via spectroscopic analyses including 2D NMR. The inhibition of α-glucosidase by the isolated xanthones was evaluated by an in vitro high-throughput screening assay. Our results indicated that 1,3,5,8-tetrahydroxyxanthone is the best inhibitor with an IC50 value of 5.33 ± 0.09 µM, while the O-glycosylated xanthones were poor α-glycosidase inhibitors.