In vitro interaction of fluconazole and berberine chloride was investigated against 40 fluconazole-resistant clinical isolates of Candida albicans. Synergism in fungistatic activity was found with the checkerboard microdilution assay. The findings of agar diffusion tests and time-kill curves confirmed the synergistic interaction, but no antagonistic action was observed.Candida albicans is the most common candidal pathogen, causing mucosal and invasive infections (7,9,23,29). With the increasing clinical use of fluconazole, a choice for the treatment of C. albicans infections (3, 5, 12), fluconazole-resistant isolates are occurring more frequently (2,19,28). Attempts have been made to cope with treatment failures by using combination therapy (14). However, contradictory results of either synergic or antagonistic actions in various antifungal combinations have been reported (8,11,16,27). As for fluconazoleresistant C. albicans, few data are available about the synergism of fluconazole with other antifungal agents (1,4,25).Berberine, a bioactive herbal ingredient, was demonstrated to have weak activity against C. albicans and C. glabrata (17,21,26). Recently, berberine was combined with amphotericin B to treat disseminated candidiasis in mice (10). To seek a novel combination therapy, we investigated the in vitro interaction of fluconazole and berberine chloride (BBR) against fluconazoleresistant clinical isolates of C. albicans.Strains and agents. Forty clinical isolates of fluconazoleresistant C. albicans were used in this study, and C. albicans ATCC 90028 was used as a quality control. Drugs prepared in dimethyl sulfoxide (DMSO) included fluconazole (PfizerRoerig Pharmaceuticals, New York, NY) and BBR (SigmaAldrich, St. Louis, MO).Checkerboard microdilution assay. Assays were performed on all 40 isolates according to methods of the CLSI (formerly NCCLS) (M27-A) (6, 18). The initial concentration of fungal suspension in RPMI 1640 medium was 10 3 CFU/ml, and the final concentrations ranged from 0.125 to 64 g/ml for fluconazole and 1 to 32 g/ml for BBR. Plates were incubated at 35°C for 24 h. Optical density was measured at 630 nm, and background optical densities were subtracted from that of each well. Each isolate was tested in triplicate. MIC 80 and MIC 50 were determined as the lowest concentration of the drugs (alone or in combination) that inhibited growth by 80% or 50%, respectively, compared with that of drug-free wells. The fractional inhibitory concentration (FIC) index is defined as the sum of the MIC of each drug when used in combination divided by the MIC of the drug used alone. Synergy and antagonism were defined by FIC indices of Յ0.5 and Ͼ4, respectively. An FIC index result of Ͼ0.5 but Յ4 was considered indifferent (20).Agar diffusion test. C. albicans 0304103 (one fluconazole-resistant isolate with a MIC of Ͼ32 g/ml for BBR) was tested by agar diffusion assay. A 100-l aliquot of 10 6 -CFU/ml suspension was spread uniformly onto the yeast extract-peptone-dextrose agar plate with or without 64 g/ml ...

Oxidative damage and inflammation are closely associated with the pathogenesis of acute lung injury (ALI). Thus, we explored the protective effect of isovitexin (IV), a glycosylflavonoid, in the context of ALI. To accomplish this, we created in vitro and in vivo models by respectively exposing macrophages to lipopolysaccharide (LPS) and using LPS to induce ALI in mice. In vitro, our results showed that IV treatment reduced LPS-induced pro-inflammatory cytokine secretion, iNOS and COX-2 expression and decreased the generation of ROS. Consistent findings were obtained in vivo. Additionally, IV inhibited H2O2-induced cytotoxicity and apoptosis. However, these effects were partially reversed following the use of an HO-1 inhibitor in vitro. Further studies revealed that IV significantly inhibited MAPK phosphorylation, reduced NF-κB nuclear translocation, and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expression in RAW 264.7 cells. In vivo, pretreatment with IV attenuated histopathological changes, infiltration of polymorphonuclear granulocytes and endothelial activation, decreased the expression of ICAM-1 and VCAM-1, reduced the levels of MPO and MDA, and increased the content of GSH and SOD in ALI. Furthermore, IV treatment effectively increased Nrf2 and HO-1 expression in lung tissues. Therefore, IV may offer a protective role against LPS-induced ALI by inhibiting MAPK and NF-κB and activating HO-1/Nrf2 pathways.

Transgenic tobacco plants carrying a number of regulatory sequences derived from the cauliflower mosaic virus 35s promoter were tested for their response to treatment with salicylic acid (SA), an endogenous signal involved in plant defense responses. PGlucuronidase (GUS) gene fusions with the full-length (-343 to +8) 35s promoter or the -90 truncation were found to be induced by SA. Time course experiments revealed that, in the continuous presence of SA, the -90 promoter construct (-90 35s-GOS) displayed rapid and transient induction kinetics, with maximum RNA levels at 1 to 4 hr, which declined to low levels by 24 hr. lnduction was still apparent in the presence of the protein synthesis inhibitor cycloheximide (CHX). Moreover, mRNA levels continued to accumulate over 24 hr rather than to decline. By contrast, mRNA from the endogenous pathogenesis-related protein-ia (PR-la) gene began to accumulate at later times during SA treatment and steadily increased thmugh 24 hr; transcription of this gene was almost completely blocked by the presence of CHX. Further dissection of the region from -90 and -46 of the 35s promoter revealed that the SAresponsive element corresponds to the previously characterized activation sequence-1 (as-í). These results represent a definitive analysis of immediate early responses to SA, relative to the late induction of PR genes, and potentially elucidate the early events of SA signal transduction during the plant defense response.

In plants, enhanced defense often compromises growth and development, which is regarded as trade-offs between growth and defense. Here we identified a gene, OsALDH2B1, that functions as a master regulator of the growth–defense trade-off in rice. OsALDH2B1 has its primary function as an aldehyde dehydrogenase and a moonlight function as a transcriptional regulator. Loss of function of OsALDH2B1 greatly enhanced resistance to broad-spectrum pathogens, including fungal blast, bacterial leaf blight, and leaf streak, but caused severe phenotypic changes such as male sterility and reduced plant size, grain size, and number. We showed that its primary function as a mitochondrial aldehyde dehydrogenase conditions male fertility. Its moonlight function of transcriptional regulation, featuring both repressing and activating activities, regulates a diverse range of biological processes involving brassinolide, G protein, jasmonic acid, and salicylic acid signaling pathways. Such regulations cause large impacts on the morphology and immunity of rice plants. The versatile functions of OsALDH2B1 provide an example of the genic basis of growth–defense trade-offs in plants.