Bacterial Communities Associated with the Roots of Typha spp. and Its Relationship in Phytoremediation Processes.

Heavy metal pollution is a severe concern worldwide, owing to its harmful effects on ecosystems. Phytoremediation has been applied to remove heavy metals from water, soils, and sediments by using plants and associated microorganisms to restore contaminated sites. The Typha genus is one of the most important genera used in phytoremediation strategies because of its rapid growth rate, high biomass production, and the accumulation of heavy metals in its roots. Plant growth-promoting rhizobacteria have attracted much attention because they exert biochemical activities that improve plant growth, tolerance, and the accumulation of heavy metals in plant tissues. Because of their beneficial effects on plants, some studies have identified bacterial communities associated with the roots of Typha species growing in the presence of heavy metals. This review describes in detail the phytoremediation process and highlights the application of Typha species. Then, it describes bacterial communities associated with roots of Typha growing in natural ecosystems and wetlands contaminated with heavy metals. Data indicated that bacteria from the phylum Proteobacteria are the primary colonizers of the rhizosphere and root-endosphere of Typha species growing in contaminated and non-contaminated environments. Proteobacteria include bacteria that can grow in different environments due to their ability to use various carbon sources. Some bacterial species exert biochemical activities that contribute to plant growth and tolerance to heavy metals and enhance phytoremediation.

Characterization of Endophytic Bacteria Isolated from Typha latifolia and Their Effect in Plants Exposed to Either Pb or Cd.

Plant-associated bacteria in heavy-metal-contaminated environments could be a biotechnological tool to improve plant growth. The present work aimed to isolate lead- and cadmium-tolerant endophytic bacteria from the roots of Typha latifolia growing in a site contaminated with these heavy metals. Endophytic bacteria were characterized according to Pb and Cd tolerance, plant-growth-promoting rhizobacteria activities, and their effect on T. latifolia seedlings exposed and non-exposed to Pb and Cd. Pb-tolerant isolates were identified as Pseudomonas azotoformans JEP3, P. fluorescens JEP8, and P. gessardii JEP33, while Cd-tolerant bacteria were identified as P. veronii JEC8, JEC9, and JEC11. They all exert biochemical activities, including indole acetic acid synthesis, siderophore production, and phosphate solubilization. Plant-bacteria interaction assays showed that P. azotoformans JEP3, P. fluorescens JEP8, P. gessardii JEP33, and P. veronii JEC8, JEC9, JEC11 promote the growth of T. latifolia seedlings by increasing the root and shoot length, while in plants exposed to either 5 mg/L of Pb or 10 mg/L of Cd, all bacterial isolates increased the shoot length and the number of roots per plant, suggesting that they are plant-growth-promoting rhizobacteria that could contribute to T. latifolia adaptation to the heavy metal polluted site.

In Vivo and In Silico Studies of the Hepatoprotective Activity of Tert-Butylhydroquinone.

Tert-butylhydroquinone (TBHQ) is a synthetic food antioxidant with biological activities, but little is known about its pharmacological benefits in liver disease. Therefore, this work aimed to evaluate TBHQ during acute liver damage induced by CCl4 (24 h) or BDL (48 h) in Wistar rats. It was found that pretreatment with TBHQ prevents 50% of mortality induced by a lethal dose of CCl4 (4 g/kg, i.p.), and 80% of BDL+TBHQ rats survived, while only 50% of the BDL group survived. Serum markers of liver damage and macroscopic and microscopic (H&E staining) observations suggest that TBHQ protects from both hepatocellular necrosis caused by the sublethal dose of CCl4 (1.6 g/kg, i.p.), as well as necrosis/ductal proliferation caused by BDL. Additionally, online databases identified 49 potential protein targets for TBHQ. Finally, a biological target candidate (Keap1) was evaluated in a proof-of-concept in silico molecular docking assay, resulting in an interaction energy of -5.5491 kcal/mol, which was higher than RA839 and lower than monoethyl fumarate (compounds known to bind to Keap1). These findings suggest that TBHQ increases the survival of animals subjected to CCl4 intoxication or BDL, presumably by reducing hepatocellular damage, probably due to the interaction of TBHQ with Keap1.

Enhanced Cd-Accumulation in Typha latifolia by Interaction with Pseudomonas rhodesiae GRC140 under Axenic Hydroponic Conditions.

The Typha genus comprises plant species extensively studied for phytoremediation processes. Recently, Pseudomonas rhodesiae GRC140, an IAA-producing bacterium, was isolated from Typha latifolia roots. This bacterium stimulates the emergence of lateral roots of Arabidopsis thaliana in the presence and absence of cadmium. However, the bacterial influence on cadmium accumulation by the plant has not been determined. Moreover, the P. rhodesiae GRC140 effect in Cd phytoextraction by T. latifolia remains poorly understood. In this work, an axenic hydroponic culture of T. latifolia was established. The plants were used to evaluate the effects of cadmium stress in axenic plants and determine the effects of P. rhodesiae GRC140 and exogenous indole acetic acid (IAA) on Cd tolerance and Cd uptake by T. latifolia. Biomass production, total chlorophyll content, root electrolyte leakage, catalase activity, total glutathione, and Cd content were determined. The results showed that Cd reduces shoot biomass and increases total glutathione and Cd content in a dose-dependent manner in root tissues. Furthermore, P. rhodesiae GRC140 increased Cd translocation to the shoots, while IAA increased the Cd accumulation in plant roots, indicating that both treatments increase Cd removal by T. latifolia plants. These results indicate that axenic plants in hydroponic systems are adequate to evaluate the Cd effects in plants and suggest that T. latifolia phytoextraction abilities could be improved by P. rhodesiae GRC140 and exogenous IAA application.

Protective Effect of Curcumin against Doxazosin- and Carvedilol-Induced Oxidative Stress in HepG2 Cells.

Doxazosin and carvedilol have been evaluated as an alternative treatment against chronic liver lesions and for their possible role during the regeneration of damage caused by liver fibrosis in a hamster model. However, these drugs have been reported to induce morphological changes in hepatocytes, affecting the recovery of liver parenchyma. The effects of these α/𝛽 adrenoblockers on the viability of hepatocytes are unknown. Herein, we demonstrate the protective effect of curcumin against the possible side effects of doxazosin and carvedilol, drugs with proven antifibrotic activity. After pretreatment with 1 µM curcumin for 1 h, HepG2 cells were exposed to 0.1-25 µM doxazosin or carvedilol for 24, 48, and 72 h. Cell viability was assessed using the MTT assay and SYTOX green staining. Morphological changes were detected using the hematoxylin and eosin (H&E) staining and scanning electron microscopy (SEM). An expression of apoptotic and oxidative stress markers was analyzed using reverse transcription-quantitative PCR (RT-qPCR). The results indicate that doxazosin decreases cell viability in a time- and dose-dependent manner, whereas carvedilol increases cell proliferation; however, curcumin increases or maintains cell viability. SEM and H&E staining provided evidence that doxazosin and carvedilol induced morphological changes in HepG2 cells, and curcumin protected against these effects, maintaining the morphology in 90% of treated cells. Furthermore, curcumin positively regulated the expression of Nrf2, HO-1, and SOD1 mRNAs in cells treated with 0.1 and 0.5 µM doxazosin. Moreover, the Bcl-2/Bax ratio was higher in cells that were treated with curcumin before doxazosin or carvedilol. The present study demonstrates that curcumin controls doxazosin- and carvedilol-induced cytotoxicity and morphological changes in HepG2 cells possibly by overexpression of Nrf2.

Curcumin Provides Hepatoprotection against Amoebic Liver Abscess Induced by Entamoeba histolytica in Hamster: Involvement of Nrf2/HO-1 and NF-κB/IL-1ß Signaling Pathways.

Amoebic liver abscess (ALA) is the most common extraintestinal amoebiasis caused by Entamoeba histolytica (E. histolytica). However, despite current knowledge and scientific advances about this infection, there are no effective treatments to prevent it. Herein, the antiamoebic capacity of curcumin in a hamster model was evaluated. Curcumin (150 mg/kg, p.o., daily during 10 days before infection) considerably prevents liver damage induced at 12 and 48 h post-intrahepatic inoculation of trophozoites and decreases ALT, ALP, and γ-GTP activities, and macroscopic and microscopic observations were consistent with these results. On the other hand, after one week of intraportal inoculation, liver damage was prevented by curcumin (150 mg/kg, p.o., daily, 20 days before amoebic inoculation and during the week of infection); liver/body weight ratios and tissue and histological stains showed normal appearance; in addition, the increases in ALT, ALP, and γ-GTP activities were prevented; the depletion of glycogen content induced by the amoebic damage was partially but significantly prevented, while NF-κB activity was inhibited and the expression of IL-1ß was reduced; Nrf2 production showed a tendency to increase it, and HO-1 protein was overexpressed. These results suggest for the first time that curcumin can be a compound with antiamoebic effect in the liver, suggesting that its daily use could help greatly decrease the incidence of this type of infection.

Curcumin and α/ß-Adrenergic Antagonists Cotreatment Reverse Liver Cirrhosis in Hamsters: Participation of Nrf-2 and NF-κB.

Liver cirrhosis is the result of an uncontrolled fibrogenetic process, due to the activation and subsequent differentiation into myofibroblasts of the hepatic stellate cells (HSC). It is known that HSC express adrenoreceptors (AR), and the use of AR antagonists protects experimental animals from cirrhosis. However, several studies suggest that the toxicity generated by metabolism of these antagonists would hinder its use in cirrhotic patients. In addition, liver fibrosis may be associated with a decrease of the antioxidant response of the nuclear factor erythroid 2-related factor 2 (Nrf-2) and the overregulation of the proinflammatory pathway of nuclear factor kappa B (NF-κB). Therefore, in the present work, the capacity of doxazosin (α1 antagonist), carvedilol (nonselective beta-adrenoceptor blocker with alpha 1-blocking properties), and curcumin (antioxidant and anti-inflammatory compound) to reverse liver cirrhosis and studying the possible modulation of Nrf-2 and NF-κB were evaluated. Hamsters received CCl4 for 20 weeks, and then treatments were immediately administered for 4 weeks more. The individual administration of doxazosin or carvedilol showed less ability to reverse cirrhosis in relation to concomitantly curcumin administration. However, the best effect was the combined effect of doxazosin, carvedilol, and curcumin, reversing liver fibrosis and decreasing the amount of collagen I (Sirius red stain) without affecting the morphology of hepatocytes (hematoxylin and eosin stain), showing normal hepatic function (glucose, albumin, AST, ALT, total bilirubin, and total proteins). In addition, carvedilol treatment and the combination of doxazosin with curcumin increased Nrf-2/NF-κB mRNA ratio and its protein expression in the inflammatory cells in the livers, possibly as another mechanism of hepatoprotection. Therefore, these results suggest for the first time that α/ß adrenergic blockers with curcumin completely reverse hepatic damage, possibly as a result of adrenergic antagonism on HSC and conceivably by the increase of Nrf-2/NF-κB mRNA ratio.

Doxazosin and Carvedilol Treatment Improves Hepatic Regeneration in a Hamster Model of Cirrhosis.

Regulation of the mechanisms of fibrosis is an important goal in the treatment of liver cirrhosis. One mechanism is the participation of hepatic stellate cells in fibrogenesis when activated by catecholamines. Consequently, α/ß adrenoblockers are proposed as an alternative treatment for chronic liver lesions such as fibrosis and/or cirrhosis and for possible liver regeneration. We herein analyzed the effect of doxazosin and carvedilol treatments during the regeneration of tissue in a hamster model of liver cirrhosis. Tissue samples were examined by H&E and PAS to evaluate tissue damage and with Sirius red to assess collagen fiber content. ALT, AST, albumin, and total proteins were examined by spectrophotometry. Determination of the levels of α-SMA and TGF-ß in hepatic tissue was examined by Western blot and of the expression of TIMP-2, MMP-13, α-FP, HGF, CK-7, and c-Myc was examined by qPCR. Treatment with doxazosin or carvedilol prompted histological recovery and reduced collagen fibers in the livers of cirrhotic hamsters. The expression of TIMP-2 decreased and that of MMP-13 increases in animals treated with adrenoblockers with respect to the group with cirrhosis. Additionally, the concentration of α-SMA and TGF-ß declined with both drugs with respect to placebo p<0.05. On the other hand, each drug treatment led to a distinct scenario for cell proliferation markers. Whereas doxazosin produced no irregularities in α-FP, Ki-67, and c-Myc expression, carvedilol induced an increment in the expression of these markers with respect to the intact. Hence, doxazosin and carvedilol are potential treatments for the regression of hepatic cirrhosis in hamsters in relation to the decrease of collagen in the hepatic parenchyma. However, at regeneration level we observed that doxazosin caused slight morphological changes in hepatocytes, such as its balonization without affecting the hepatic function, and on the other hand, carvedilol elicited a slight irregular expression of cell proliferation markers.

Adrenergic regulation during acute hepatic infection with Entamoeba histolytica in the hamster: involvement of oxidative stress, Nrf2 and NF-KappaB.

Oxidative stress and transcriptional pathways of nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa-B (NF-κB) are critically involved in the etiopathology of amebic liver abscess (ALA). In this work, we studied the relationship between the adrenergic nervous system and ALA in the hamster. ALA was visible at 12 h of infection. While 6-hydroxidopamine (6-OHDA) decreased infection, propranolol (ß-adrenergic blocker) treatment was associated with less extensive liver damage, and phentolamine treatment (α-adrenergic blocker) significantly reduced ALA compared to 6-OHDA and propranolol. Serum enzymatic activities of alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (γ-GTP) were increased at 12 h post-infection. Chemical denervation and α and ß-adrenergic blockers decreased ALT to normal levels, while 6-OHDA and propranolol showed a trend to decrease γ-GTP but phentolamine significantly reduced γ-GTP. Amebic infection increased oxidized glutathione (GSSG) and decreased both reduced glutathione (GSH) and the GSH/GSSG ratio. Propranolol and 6-OHDA showed a tendency to decrease GSSG. However, GSH, GSSG and GSH/GSSG returned to normal levels with phentolamine. Furthermore, amebic infection increased pNF-κB and interleukin-1ß (IL-1ß), and showed a tendency to decrease hemoxigenase-1 (HO-1), but not Nrf2. Chemical denervation showed a trend to decrease pNF-κB and IL-1ß, and neither Nrf2 nor HO-1 increased significantly. In addition, NF-κB and IL-1ß were attenuated by propranolol and phentolamine treatments, although phentolamine showed significant overexpression of Nrf2 and HO-1. This suggests that the adrenergic system may be involved in oxidative stress and in modulation of the Nrf2 and NF-κB pathways during ALA development.

The chemopreventive capacity of quercetin to induce programmed cell death in hepatocarcinogenesis.

In this study of chemoprevention in the rat modified resistant hepatocyte model, preneoplastic cells were diminished by >60% with quercetin pretreatment compared with those rats treated with N-Diethylnitrosamine (DEN) to induce liver cancer. This decrease occurred associated with an abolished DEN-induced lipid peroxidation as well as activation of caspase 9 and increased caspase 3, as determined by increased expression of cleaved caspase 3 and 9, but not cleaved caspase 8 and increased fragmentation of Poly (ADP-ribose) polymerase (PARP) inducing apoptosis of presumed genetically injured cells, when quercetin was administered before the initiation agent.

Celecoxib enhances the detoxification of diethylnitrosamine in rat liver cancer.

AIM: To study the effect of celecoxib (CXB) on diethylnitrosamine activation through the regulation of cytochrome P450 in a hepatocarcinogenesis model. METHODS: Six-week-old male Sprague-Dawley rats were randomly divided into five groups, a non-treated group (NT), a diethylnitrosamine-treated group (DEN), a DEN+CXB-treated group (DEN+CXB), and CXB 8 d-treated and CXB 32 d-treated groups. The effects of celecoxib on the enzymatic activities of CYP1A1, 2A, 2B1/2, and 2E1 were assessed in hepatic microsomes 24 h after DEN administration. Changes in CYP1A1 and CYP2B1/2 protein expression were also evaluated. The rate of DEN metabolism was measured by the production of the deethylation metabolite acetaldehyde, and the denitrosation metabolite nitrite. RESULTS: DEN+CXB administration produced a significant increase in the enzymatic activities of CYP2B1/2 and 1A1, whereas it did not change the activities of CYP2A and 2E1, compared to that of the DEN group. CXB treatment for eight days did not produce a significant effect on enzymatic activity when compared to the NT group; however, when it was administered for prolonged times (CXB 32 d group), the enzymatic activities were increased in a similar pattern to those in the DEN+CXB group. The observed increase in the enzymatic activities in the DEN+CXB group was accompanied by an increase in the CYP2B1/2 protein levels; no changes were observed in the levels of CYP1A1. In vitro, CXB increased the denitrosation of DEN, a pathway of metabolic detoxification. The addition of SKF-525A, a preferential inhibitor of CYP2B, abrogated the denitrosation of DEN. CONCLUSION: These results suggest that the mechanism of action of CXB involves enhancement of the detoxification of DEN by an increasing denitrosation via CYP2B1/2.