Antibacterial activity of tannins towards Pseudomonas syringae pv. tomato, and their potential as biostimulants on tomato plants

Pseudomonas syringae pv. tomato (Pst), the causal agent of bacterial speck of tomato, is a significant cause of economic losses in tomato crops. This disease is mainly controlled with preventive use of cupric salt formulations. Antibacterial activity of the tannins U1, U2, U3 and U4, applied alone at 1% w/v concentration or in combination with half (0.045% w/v) of standard of copper hydroxide treatments, was assayed for effects on Pst. In vitro, the four tannins completely inhibited Pst colony formation after 24 h, but U2 (quebracho tannins) + ½ Cu(OH)2 allowed Pst growth after 48 h of incubation, indicating that, since U2 is composed of high molecular condensed tannins it is likely that their structures have chelated the copper hydroxide much more then hydrolysable ones, thus inactivating copper hydroxide and tannins. In fact, this activity of the tannins was equivalent to that for 0.045% w/v of copper hydroxide. Effects of tannins on tomato plant growth were also assessed. On seedlings, long-term U1 treatments increased dry weight of shoots compared to copper hydroxide, but not to water treatment. The U4 treatment increased the NBI values compared to copper treatment but did not show significant differences compared to the water treatment. Inhibitory activity of tannin treatments reduced disease by 37–62%, and 60% after copper treatment, while disease severity was reduced by 33–54% after treating plants with tannins and 36% after copper treatment. On mature plants treated once, the disease reduction was 27–39% after tannin treatments and 44% after copper treatment, while severity was reduced by 50–60% from tannin treatments, and 47% by copper. In seedlings and mature plants, these reductions were similar (P > 0.05) for the tannins and copper treatments. This study indicates a novel crop protection strategy using natural products as alternatives to xenobiotic compounds.

Effect of copper sulfate on the external microbiota of adult common snook (Centropomus undecimalis)

Background The environment exerts a strong influence on the fish external microbiota, with lower diversity and increased abundances of opportunistic bacterial groups characterizing cultured fish compared to their wild counterparts. Deviation from a healthy external microbiota structure has been associated with increased susceptibility to bacterial pathogens. Treatment of wild-caught broodstock with copper sulfate for the removal of external parasites is a common aquaculture practice. Despite the microbiota’s importance to fish health, the effects of copper sulfate on mucosal bacterial communities and their ability to recover following this chemical treatment have not been examined. The skin microbiota of adult common snook was characterized from wild individuals (Wild), and wild-caught fish maintained in recirculating aquaculture systems (RAS) immediately following a month-long copper sulfate treatment (Captive-1), and then two-weeks (Captive-2) and 2 years (Captive-3) after cessation of copper treatment. Results The skin microbiota of wild fish were characterized by high diversity and taxa including Synechocococcus, SAR11, and a member of the Roseobacter clade. Bacterial diversity decreased in Captive individuals during the 2-year sampling period. Captive fish harbored greater abundances of Firmicutes, which may reflect glycan differences between aquaculture and natural feeds. Bacterial taxa with copper resistance mechanisms and indicative of metal contamination were enriched in Captive-1 and Captive-2 fish. Vibrionaceae were dominant in Captive fish, particularly immediately and 2 weeks following copper treatment. Based on our observations and previous literature, our results suggest putatively beneficial taxa amass over time in captivity. Within 2 years, Captive individuals harbored Bacillus which contains numerous probiotic candidates and the complex carbon degraders of the family Saprospiraceae. Predicted butanoate metabolism exceeded that of Wild fish, and its reported roles in immunity and energy provision suggest a prebiotic effect for fishes. Conclusions The mucosal microbiota contains bacterial taxa that may act as bioindicators of environmental pollution. Increases in mutualistic groups indicate a return to a beneficial skin microbiota following copper sulfate treatment. Our data also suggests that vastly different taxa, influenced by environmental conditions, can be associated with adult fish without noticeable health impairment, perhaps due to establishment of various mutualists to maintain fish mucosal health.

Iron metabolism is disturbed and anti-copper treatment improves but does not normalize iron metabolism in Wilson’s disease

Wilson’s disease (WD) is a rare hereditary disorder of copper metabolism. Some data suggest that iron metabolism is disturbed in WD and this may affect the course of the disease. The current study aimed to determine whether anti-copper treatment could affect iron metabolism in WD. One hundred thirty-eight WD patients and 102 controls were examined. Serum ceruloplasmin and copper were measured by colorimetric enzyme assay or atomic adsorption spectroscopy, respectively. Routine and non-routine parameters of iron metabolism were measured by standard laboratory methods or enzyme immunoassay, respectively. WD patients, both newly diagnosed and treated, had less serum copper and ceruloplasmin than controls (90.0, 63.0, 22.0 mg/dL, respectively, p < 0.001); in the treated patients blood copper and ceruloplasmin were lower than in untreated patients (p < 0.001). Untreated patients (n = 39) had a higher median blood iron (126.0 vs 103.5 ug/dL, p < 0.05), ferritin (158.9 vs 47.5 ng/mL, p < 0.001), hepcidin (32, 6 vs 12.1 ng/mL, p < 0.001) and sTfR (0.8 vs. 0.7 ug/mL, p < 0.001) and lower blood transferrin (2.4 vs. 2.7 g/L, p < 0.001), TIBC (303.0 vs 338.0 ug/dL, p < 0.001), hemoglobin (13.1 vs 13.9 g/dL, p < 0.01) and RBC (4.3 vs. 4.6, p < 0.002) than controls. Treated patients (n = 99) had a significantly lower median iron (88.0 vs. 126.0 ug/dL, p < 0.001), ferritin (77.0 vs. 158.9 ng/mL, p < 0.005) and hepcidin (16.7 vs. 32.6 ng/mL, p < 001) and higher transferrin (2.8 vs. 2.4 g/L, p < 0.005), TIBC (336.0 vs 303.0 ug/dL, p < 0.001), RBC (4.8 vs. 4.3 M/L, p < 0.001) and hemoglobin (14.4 vs. 13.1 g/dL, p < 0.001) than untreated; the median iron (p < 0.005) was lower, and ferritin (p < 0.005), RBC (p < 0.005) and hepcidin (p < 0.002) were higher in them than in the control group. Changes in copper metabolism are accompanied by changes in iron metabolism in WD. Anti-copper treatment improves but does not normalize iron metabolism.

Essential Gene Clusters Involved in Copper Tolerance Identified in Acinetobacter baumannii Clinical and Environmental Isolates

Copper is widely used as antimicrobial in agriculture and medicine. Copper tolerance mechanisms of pathogenic bacteria have been proven to be required for both copper tolerance and survival during bacterial infections. Here, we determined both copper-tolerant phenotype and genotype in A. baumannii originated from clinical and environmental samples. Using copper susceptibility testing, copper-tolerant A. baumannii could be found in both clinical and environmental isolates. Genotypic study revealed that representative copper-related genes of the cluster A (cueR), B (pcoAB), and D (oprC) were detected in all isolates, while copRS of cluster C was detected in only copper-tolerant A. baumannii isolates. Moreover, we found that copper-tolerant phenotype was associated with amikacin resistance, while the presence of copRS was statistically associated with blaNDM-1. We chose the A. baumannii strain AB003 as a representative of copper-tolerant isolate to characterize the effect of copper treatment on external morphology as well as on genes responsible for copper tolerance. The morphological features and survival of A. baumannii AB003 were affected by its exposure to copper, while whole-genome sequencing and analysis showed that it carried fourteen copper-related genes located on four clusters, and cluster C of AB003 was found to be embedded on genomic island G08. Transcriptional analysis of fourteen copper-related genes identified in AB003 revealed that copper treatment induced the expressions of genes of clusters A, B, and D at the micromolar level, while genes of cluster C were over-expressed at the millimolar levels of copper. This study showed that both clinical and environmental A. baumannii isolates have the ability to tolerate copper and carried numerous copper tolerance determinants including intrinsic copper tolerance (clusters A, B, and D) and acquired copper tolerance (cluster C) that could respond to copper toxicity. Our evidence suggests that we need to reconsider the use of copper in hospitals and other medical environments to prevent the selection and spread of copper-tolerant organisms.

Persistence with treatment for Wilson disease: a retrospective study

Background Wilson disease (WD) is genetically induced failure of copper metabolism which can be successfully treated with pharmacological agents. The prognosis for survival in most WD patients is favorable if diagnosis and anti-copper treatment are provided early. Many observations imply that persistence with drug treatment is generally low in patients with chronic diseases, which impact the treatment effectiveness, but such results are very limited in WD. The aim of our study was to assess persistence with treatment among WD patients, to analyze its effect on patient outcome and to identify factors that might be related to persistence. Methods 170 newly diagnosed, symptomatic patients with WD who started treatment between 1995 and 2005 were analyzed retrospectively to assess treatment non-persistence, which was defined as at least one reported break of more than 3 months or minimum two breaks lasting longer than 2 months. Results were further analyzed according to selected clinical variables. Results Only 74.1% of patients were persistent with treatment during the mean 11.7 years of follow up. Treatment persistence closely impacted positive clinical outcomes. In patients classified as persistent, improvement and lack of WD progression were observed more often compared to those classified as non-persistent (29.4 and 68.3% vs. 2.3 and 45.5%; p < 0.001, respectively). In contrast, non-persistent patients presented more often with worsening WD than persistent patients (52.3% vs. 2.4%). Type of WD treatment, gender, phenotypic presentation, adverse events and duration of treatment were not related to treatment persistence. Higher or upper/post-secondary education and a supportive family attitude towards treatment were the most important factors related to persistence. Conclusions One quarter of WD patients were not taking anti-copper treatment regularly and this had an important negative effect on clinical outcome. Family support played an important role in treatment persistence.