Autotrophic denitrification by sulfur-based immobilized electron donor for enhanced nitrogen removal: Denitrification performance, microbial interspecific interaction and functional traits

Sulfur-driven autotrophic denitrification (SdAD) is a promising nitrogen removing process, but its applications were generally constrained by conventional electron donors (i.e., thiosulfate (Na2S2O3)) with high valence and limited bioavailability. Herein, an immobilized electron donor by loading elemental sulfur on the surface of polyurethane foam (PFSF) was developed, and its feasibility for SdAD was investigated. The denitrification efficiency of PFSF was 97.3%, higher than that of Na2S2O3 (91.1%). Functional microorganisms (i.e., Thiobacillus and Sulfurimonas) and their metabolic activities (i.e., nir and nor) were substantially enhanced by PFSF. PFSF resulted in the enrichment of sulfate-reducing bacteria, which can reduce sulfate (SO42-). It attenuated the inhibitory effect of SO42-, whereas the generated product (hydrogen sulfide) also served as an electron donor for SdAD. According to the economic evaluation, PFSF exhibited strong market potential. This study proposes an efficient and low-cost immobilized electron donor for SdAD and provides theoretical support to its practical applications.

Disruption of Bioenergetics in the Intestine of Wistar Rats Caused by Hydrogen Sulfide and Thiosulfate: A Potential Mechanism of Chronic Hemorrhagic Diarrhea in Ethylmalonic Encephalopathy

Ethylmalonic encephalopathy (EE) is a severe inherited metabolic disorder that causes tissue accumulation of hydrogen sulfide (sulfide) and thiosulfate in patients. Although symptoms are predominantly neurological, chronic hemorrhagic diarrhea associated with intestinal mucosa abnormalities is also commonly observed. Considering that the pathophysiology of intestinal alterations in EE is virtually unknown and that sulfide and thiosulfate are highly reactive molecules, the effects of these metabolites were investigated on bioenergetic production and transfer in the intestine of rats. We observed that sulfide reduced NADH- and FADH2-linked mitochondrial respiration in the intestine, which was avoided by reduced glutathione (GSH) but not by melatonin. Thiosulfate did not change respiration. Moreover, both metabolites markedly reduced the activity of total, cytosolic and mitochondrial isoforms of creatine kinase (CK) in rat intestine. Noteworthy, the addition of GSH but not melatonin, apocynin, and Trolox (hydrosoluble vitamin E) prevented the change in the activities of total CK and its isoforms caused by sulfide and thiosulfate, suggesting a direct protein modification on CK structure by these metabolites. Sulfide further increased thiol content in the intestine, suggesting a modulation in the redox state of these groups. Finally, sulfide and thiosulfate decreased the viability of Caco-2 intestinal cells. Our data suggest that bioenergetic impairment caused by sulfide and thiosulfate is a mechanism involved in the gastrointestinal abnormalities found in EE.

Effects of sodium thiosulfate on serum calcification factors in patients undergoing maintenance hemodialysis

OBJECTIVE

To investigate the effect of sodium thiosulfate (STS) on serum calcification factors in patients undergoing maintenance hemodialysis.

METHODS

Forty-four Patients were randomly divided into control group (n = 22) and observation group (n = 22) by envelope method (block 4 randomization). The control group received routine treatment while observation group was treated with STS on the basis of routine treatment. The biochemical indicators, including BUN, UA, SCr, Ca2+ , P3- , calcium-phosphorus product, PTH, hs-CRP, TG, TC, HDL, LDL, and serum calcification factor MGP, FA, FGF-23, and OPG levels were compared before and after treatment.

RESULTS

Control group had no statistically significant difference in the levels of vascular calcification factors MGP, FA, FGF-23, and OPG before and after treatment (p > 0.05). Whereas observation group had higher levels of MGP and FA, and lower levels of FGF-23 and OPG after treatment than before treatment (p < 0.05). The levels of MGP and FA in observation group were higher than those in control group, and FGF-23 and OPG were lower than those in control group (p < 0.05).

CONCLUSION

It is speculated that sodium thiosulfate can alleviate the progression of vascular calcification by changing the levels of calcification factors.

Effects of Sodium Thiosulfate During Resuscitation From Trauma-and-Hemorrhage in Cystathionine Gamma Lyase (CSE) Knockout Mice

BACKGROUND

Sodium thiosulfate (Na2S2O3) is a clinically established drug with antioxidant and sulphide-releasing properties. Na2S2O3 mediated neuro- and cardioprotective effects in ischemia/reperfusion models and anti-inflammatory effects in LPS-induced acute lung injury. Moreover, Na2S2O3 improved lung function during resuscitation from hemorrhagic shock in swine with pre-existing atherosclerosis, characterized by decreased expression of cystathionine γ-lyase (CSE), a major source of hydrogen sulfide (H2S) synthesis in the vasculature. Based on these findings, we investigated the effects of Na2S2O3 administration during resuscitation from trauma-and-hemorrhage in mice under conditions of whole body CSE deficit.

METHODS

After blast wave-induced blunt chest trauma and surgical instrumentation, CSE knockout (CSE-/-) mice underwent 1 h of hemorrhagic shock (MAP 35 ± 5 mm Hg). At the beginning of resuscitation comprising retransfusion, norepinephrine support and lung-protective mechanical ventilation, animals received either i.v. Na2S2O3 (0.45 mg g-1, n = 12) or vehicle (saline, n = 13). Hemodynamics, acid-base status, metabolism using stable isotopes, and visceral organ function were assessed. Blood and organs were collected for analysis of cytokines, mitochondrial respiratory capacity, and immunoblotting.

RESULTS

Na2S2O3 treatment improved arterial paO2 (P = 0.03) coinciding with higher lung tissue glucocorticoid receptor expression. Norepinephrine requirements were lower in the Na2S2O3 group (P < 0.05), which was associated with lower endogenous glucose production and higher urine output. Na2S2O3 significantly increased renal tissue IκBα and heme oxygenase-1 expression, whereas it lowered kidney IL-6 and MCP-1 levels.

CONCLUSION

Na2S2O3 exerted beneficial effects during resuscitation of murine trauma-and-hemorrhage in CSE-/- mice, confirming and extending the previously described organ-protective and anti-inflammatory properties of Na2S2O3. The findings make Na2S2O3 a potentially promising therapeutic option in the context of impaired CSE activity and/or reduced endogenous H2S availability.

Distinct Functions of Ethylene and ACC in the Basal Land Plant Marchantia polymorpha

Ethylene is a gaseous phytohormone involved in various physiological processes, including fruit ripening, senescence, root hair development and stress responses. Recent genomics studies have suggested that most homologous genes of ethylene biosynthesis and signaling are conserved from algae to angiosperms, whereas the function and biosynthesis of ethylene remain unknown in basal plants. Here, we examined the physiological effects of ethylene, an ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) and an inhibitor of ethylene perception, silver thiosulfate (STS), in a basal land plant, Marchantia polymorpha. M. polymorpha plants biosynthesized ethylene, and treatment with high concentrations of ACC slightly promoted ethylene production. ACC remarkably suppressed the growth of thalli (vegetative organs) and rhizoids (root-hair-like cells), whereas exogenous ethylene slightly promoted thallus growth. STS suppressed thallus growth and induced ectopic rhizoid formation on the dorsal surface of thalli. Thus, ACC and ethylene have different effects on the vegetative growth of M. polymorpha. We generated single and double mutants of ACC synthase-like (ACSL) genes, MpACSL1 and MpACSL2. The mutants did not show obvious defects in thallus growth, ACC content and ethylene production, indicating that MpACSL genes are not essential for the vegetative growth and biosynthesis of ACC and ethylene. Gene expression analysis suggested the involvement of MpACSL1 and MpACSL2 in stress responses. Collectively, our results imply ethylene-independent function of ACC and the absence of ACC-mediated ethylene biosynthesis in M. polymorpha.

'Antioxidant' berries, anthocyanins, resveratrol and rosmarinic acid oxidize hydrogen sulfide to polysulfides and thiosulfate: A novel mechanism underlying their biological actions

Nutraceutical polyphenol catechins in green tea oxidize H2S to polysulfides (PS) in buffer and in cells thereby conveying their cytoprotective effects. Here we measure H2S oxidation in buffer and HEK293 cells by over-the-counter nutraceuticals, blueberry, bilberry and cranberry, and by polyphenols, cyanadin (Cya), quercetin (Que), rosmarinic acid (RA) and resveratrol (Res). H2S and PS were measured with specific fluorophores, AzMc and SSP4 respectively, and thiosulfate (TS) production was measured in buffer using silver nanoparticles (AgNPs). All compounds increased polysulfide production from H2S in buffer and increased polysufides in cells. Decreasing oxygen from 100% to 21% and 0% progressively decreased PS production by Que and RA in buffer and Que decreased PS production in cells incubated in 5% O2 compared to 21% O2. Que, RA and Res, but not Cya, increased TS production from H2S in 21% O2 but not in 0% O2. Superoxide dismutase did not affect PS production from H2S by Que or TS production from H2S by Que, RA or Res, whereas catalase inhibited TS production by all three polyphenols. Conversely, these polyphenols only slightly reduce a mixed polysulfide (K2Sn) or thiosulfate to H2S in 0% O2. Collectively, our results suggest that polyphenols are autoxidized to a semiquinone radical and that this, in turn, oxidizes H2S to a thiyl radical from which polysulfides and thiosulfate derived. They also suggest that this is catalyzed by a semiquinone radical and it is independent of either superoxide or hydrogen peroxide concomitantly produced during polyphenol autoxidation. The polysulfides produced in these reactions are potent antioxidants and also initiate a variety of downstream cytoprotective effector mechanisms. It is also possible that H2S can be regenerated from the thiosulfate produced in these reactions by other cellular reductants and reused in subsequent reactions.

Sodium Thiosulfate Ameliorates Renovascular Hypertension-Induced Renal Dysfunction and Injury in Rats

BACKGROUND/AIMS

Arterial stenosis activates the renin-angiotensin-aldosterone system subsequently resulting in renovascular hypertension (RVHT) and renal oxidative injury. We explored the effect of sodium thiosulfate (STS, Na2S2O3), a developed antioxidant in clinical trial, on RVHT-induced hypertension and renal oxidative injury in rats.

METHODS

We induced RVHT in male Wistar rats with bilaterally partial ligation of renal arteries in the 2-kidney 2-clip model. We evaluated the STS effect on RVHT-induced oxidative injury and apoptosis by a chemiluminescence amplification method, Western blot, and immunohistochemistry.

RESULTS

We found STS displayed a dose-dependent antioxidant H2O2 activity and adapted the maximal scavenging H2O2 activity of STS at the dosage of 0.1 g/kg intraperitoneally 3 times/week for 4 weeks in RVHT rats. RVHT induced a significant elevation of arterial blood pressure, blood reactive oxygen species amount, neutrophil infiltration, 4-HNE and NADPH oxidase gp91 expression, Bax/Bcl-2/poly(ADP-ribose) polymerase (PARP)-mediated apoptosis formation, blue Masson-stained fibrosis, and urinary protein level. STS treatment significantly reduced hypertension, oxidative stress, neutrophil infiltration, fibrosis, and Bax/Bcl-2/PARP-mediated apoptosis formation and depressed the urinary protein level in the RVHT models.

CONCLUSION

Our results suggest that STS treatment could ameliorate RVHT hypertension and renal oxidative injury through antioxidant, antifibrotic, and antiapoptotic mechanisms.

Assaying the use of sodium thiosulphate as a biostimulant and its effect on cadmium accumulation and tolerance in Brassica oleracea plants

An optimal uptake of mineral elements is crucial to ensure both crop yield and quality. The use of biostimulants is taking relevance to improve the nutrition of crops. Sulphur (S) is one of the elements with great potential within biostimulants. Furthermore, soil contamination by heavy metals such as cadmium (Cd) has become a serious environmental problem. Different studies have suggested the use of thiosulphate (TS) as a biostimulant and to increase the phytoremediation capacity of plants. Therefore, in the present study, we use a crop plant with high S requirements such as Brassica oleracea, to test whether TS serves as a biostimulant and whether affects Cd accumulation and tolerance. B. oleracea plants were grown with two different TS doses (2 mM and 4 mM), under Cd toxicity, and with the combination of Cd toxicity and both TS doses. Parameters of biomass, mineral elements accumulation, and stress tolerance were analyzed. The results showed that TS reduced biomass of B. oleracea plants. The application of 2 mM TS increased Cd accumulation whereas the 4 mM dose reduced it. On the other hand, TS incremented micronutrient accumulation on plants subjected to Cd toxicity and increased Zn contents. Besides, the application of 2 mM to Cd-stressed plants enhanced photosynthesis performance and reduced oxidative stress. Finally, TS increased the antioxidant capacity of B. oleracea plants. Briefly, although TS can not be used as a biostimulant it could be used for Cd phytoremediation purposes and to enhance Zn accumulation in B. oleracea plants.

Transcription Factor Nrf2 as a Potential Therapeutic Target for Prevention of Cytokine Storm in COVID-19 Patients

Nrf2 is a key transcription factor responsible for antioxidant defense in many tissues and cells, including alveolar epithelium, endothelium, and macrophages. Furthermore, Nrf2 functions as a transcriptional repressor that inhibits expression of the inflammatory cytokines in macrophages. Critically ill patients with COVID-19 infection often present signs of high oxidative stress and systemic inflammation - the leading causes of mortality. This article suggests rationale for the use of Nrf2 inducers to prevent development of an excessive inflammatory response in COVID-19 patients.

Sodium Thiosulfate in the Pregnant Dahl Salt-Sensitive Rat, a Model of Preeclampsia

Aberrant production of hydrogen sulfide (H₂S) has been linked to preeclampsia. We hypothesized that sodium thiosulfate (STS), a H₂S donor, reduces hypertension and proteinuria, and diminishes fetal growth restriction in the Dahl salt-sensitive (S) rat, a spontaneous model of superimposed preeclampsia. In addition to a control group (n = 13), two groups received STS via drinking water at a dose of 2 g (n = 9) or 3 g per kg body weight per day (n = 8) from gestational day (GD) 10 to 20. Uterine artery resistance index was measured (GD18), urinary protein excretion rate was determined (GD19), and blood pressure and fetal outcomes were evaluated (GD20). At 2 g, STS had no effect on preeclamptic symptoms or fetal outcome. At 3 g, STS reduced maternal hypertension (121.8 ± 3.0 vs. 136.3 ± 2.9), but increased proteinuria (89 ± 15 vs. 56 ± 5 mg/24h), and relative kidney weight (0.86 ± 0.04 vs. 0.73 ± 0.02%). Fetal/placental weight ratio was reduced (3.83 ± 0.07 vs. 4.31 ± 0.08) without affecting litter size. No differences in uterine artery flow or renal histological damage were noted across treatment groups. While these data suggest a promising antihypertensive effect that could imply prolongation of preeclamptic pregnancies, the unfavorable effects on proteinuria, kidney weight, and fetal/placental weight ratio implies that clinical implementation of STS is contra-indicated until safety for mother and child can be verified.

Comparative study of the effects of different chelating ligands on the absorption and transport of mercury in maize (Zea mays L.)

Mercury (Hg) pollution seriously threatens food safety and has attracted global attention. Phytoextraction, due to its low cost, applicability, and environmental friendliness, is considered a new technology for clean-up of heavy metal contamination in the environment. However, the low bioavailability of Hg in polluted areas greatly limits the applicability of phytoextraction. Here, we compared the effects of six common chelating ligands on the absorption and transport of Hg in maize (Zea mays L.), which has a high biomass and short growth cycle. The results showed that the root length and biomass of maize seedlings of the groups treated with the six chelating ligands (EDTA, iodide, ammonium, thiosulfate, thiocyanate, and thiocarbamide) did not change compared with those of the non-treated groups. Co-exposure to Hg and each chelating ligand markedly alleviated the inhibitory effect induced by Hg. Iodide treatment resulted in the lowest root Hg content and highest translocation factor (TF) value, while ammonium treatment gave rise to the highest shoot Hg concentration and lowest TF. Compared with other chelating ligands, thiosulfate exhibited the maximum alleviation of Hg toxicity and achieved the highest concentration of Hg in the roots and aerial parts. Moreover, the TF and Hg accumulation in the thiosulfate and Hg co-exposed group were much higher than those in the group exposed to Hg alone. This finding suggests that, among these common chelating ligands, thiosulfate compounds have great potential for Hg phytoextraction, while the others can immobilize Hg in polluted areas.

The quality of barley husk-caryopsis adhesion is not correlated with caryopsis cuticle permeability

Adhesion of the barley husk to the underlying caryopsis requires the development of a cuticular cementing layer on the caryopsis surface. Differences in adhesion quality among genotypes have previously been correlated with cementing layer composition, which is thought to influence caryopsis cuticle permeability, the hypothesised mechanism of adhesion mediation. It is not yet known whether differences in adhesion quality among genotypes are determined by changes in caryopsis cuticle permeability. We examined changes in candidate cementing layer biosynthetic and regulatory genes to investigate the genetic mechanisms behind husk adhesion quality. We used both commercially relevant UK malting cultivars and older European lines to ensure phenotypic diversity in adhesion quality. An ethylene responsive transcription factor (NUD) is required for the development of the cementing layer. To examine correlations between gene expression, cementing layer permeability and husk adhesion quality we also treated cultivars with ethephon (2-chloroethylphosphonic acid) which breaks down to ethylene, and silver thiosulphate which inhibits ethylene reception, and measured caryopsis cuticle permeability. Differential adhesion qualities among genotypes are not determined by NUD expression during development of the cementing material alone, but could result from differences in biosynthetic gene expression during cementing layer development in response to longer-term NUD expression patterns. Altered caryopsis cuticle permeability does result in altered adhesion quality, but the correlation is not consistently positive or negative. Cuticle permeability is therefore not the mechanism that determines husk adhesion quality, but is likely a consequence of the required cuticular compositional changes that determine adhesion.

Quenching by sodium thiosulfate does not influence 16S rRNA gene sequencing profiles of reclaimed water from three sites in the Mid-Atlantic, United States

A quenching agent is commonly added to chlorinated, reclaimed water during sample collection to prevent chlorine-mediated die-off of viable microbiota. However, the effect of quenching on downstream 16S rRNA-based bacterial community analyses is unclear. We conducted a side-by-side comparison of 16S rRNA sequencing data from reclaimed water samples quenched with sodium thiosulfate and non-quenched samples. Our data showed that 16 S rRNA processing and sequencing methods, and resulting bacterial profiles, were not negatively impacted by quenching.

Signaling and physiological activity of the NO-donating agent TNICthio in human blood lymphocytes, Jurkat and MCF7 cell lines

Signaling and physiological activities of the crystalline tetranitrosyl iron complex with thiosulfate-a NO-donor (TNICthio) were first studied on human cells in conditions of mono and combined application of H₂S and antioxidants. Comparative studies were performed on three cell lines: normal and leukemic T lymphocytes (Jurkat cells) and breast cancer MCF-7 cells (human breast adenocarcinoma). Also established was a high biological activity of TNICthio, as well as correlation between the levels of reactive oxygen species generation, the formation of double-strand breaks (DSB) in DNA and cell proliferation. The amount of DNA DSB repair in normal lymphocytes was tenfold higher than in leukemic cells. Inorganic H₂S donor sodium hydrosulfide (NaHS) had insignificant effects on the production of reactive oxygen species and generation of DNA DSB in the cells of all the lines under study. However, H₂S increased the tolerance of cells to the stress response after combined cell treatment with NO + H₂S. 0.5 mM NO-donor and 0.1 mM antitumor antibiotic doxorubicin were equally effective generators of reactive oxygen species in MCF-7 cells; however, antiproliferative activity of the NO-donor, in this case, proved to be twice higher. The results obtained in this work may be promising for the prediction of pro- and antioxidant properties of the new NO and H₂S donating compounds, as well as for the development of methods for complex anticancer therapy.

Hydrogen sulfide donor, NaHS, stimulates ANP secretion via the KATP channel and the NOS/sGC pathway in rat atria

Hydrogen sulfide (H₂S) is normally produced from l-cysteine in mammalian tissues and related to the pathogenesis of cardiovascular diseases. The aim of this study is to investigate the effects of H₂S donor on atrial natriuretic peptide (ANP) secretion and define its mechanism using normal and isoproterenol (ISP)-treated rats. Several H₂S donors were perfused into isolated beating rat atria, and atrial pressure (AP) and ANP secretion were measured. NaHS augmented high stretch-induced ANP secretion and decreased AP in a dose-dependent manner. The high stretch-induced ANP secretion was stimulated by Na₂S but was not changed by GYY4137 and sodium thiosulfate. NaHS and Na₂S produced very high amount of H₂S rapidly whereas GYY4137 produced very low amount of H₂S slowly. NaHS-stimulated ANP secretion was blocked by the pretreatment with inhibitor for K_ATP channel, nitric oxide synthase (NOS), soluble guanylyl cyclase (sGC), phosphoinositol 3 kinase (PI3K) or protein kinase B. H₂S synthesis enzyme inhibitor (DL-propargylglycine) did not show any significant changes in atrial parameters. However, the response of ANP secretion to NaHS markedly attenuated and DL-propargylglycine suppressed ANP secretion in ISP-treated rat atria. The expression of eNOS protein was decreased but the expression of cardiomyocyte-specific H₂S producing enzyme, cystathione γ-lyase, was not changed in ISP-treated rat atria. The attenuation of NaHS-induced ANP secretion in ISP-treated rat atria may be due to the low expression of eNOS protein. These findings clarify that NaHS stimulates ANP secretion via the K_ATP channel and the PI3K/Akt/NOS/sGC pathway in rat atria.

Enhancer assisted-phytoremediation of mercury-contaminated soils by Oxalis corniculata L., and rhizosphere microorganism distribution of Oxalis corniculata L

The present study investigated remediation of mercury-contaminated soils using Oxalis corniculata L. combined with various enhancers (sodium thiosulfate, ammonium thiosulfate, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid). The experiment was conducted using Oxalis corniculata seedlings planted in pots containing mercury loaded soils. Investigations included analysis of soil properties, plant growth conditions, ability of the plants to accumulate and extract mercury, and rhizosphere microorganism distribution. The maximal mercury content of the aerial parts and the mercury-translocation ratio of Oxalis corniculata treated with enhancers increased compared to Oxalis corniculata without enhancers. Compared with no enhancers, the theoretical reduction in phytoremediation time was about 50%, 25%, 20% and 21% when Oxalis corniculata was treated with sodium thiosulfate (Na₂S₂O₃), ammonium thiosulfate ((NH₄)₂S₂O₃), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA), respectively. The results indicated that the dominant species in rhizosphere soils varied with different enhancers. However, the evenness of background soils, rhizosphere soils of Oxalis corniculata, Oxalis corniculata treated with Na₂S₂O₃, (NH₄)₂S₂O₃, EDTA and DTPA was not largely different at 0.62, 0.61, 0.57, 0.64, 0.61 and 0.63, respectively. These findings demonstrate that Oxalis corniculata treated with Na₂S₂O₃ has the potential to recover and reclaim mercury-contaminated soils in pots.

Dicyandiamide has more inhibitory activities on nitrification than thiosulfate

Dicyandiamide (DCD) and thiosulfates are two type of nitrification inhibitors (NIs) that have been widely used in agriculture to improve nitrogen (N) fertilizer use efficiency and mitigate negative effect of N on environment. Little information is available concerning the comparison of the efficacy of DCD and thiosulfate on N transformations in soil. The aim of this study was to compare the effects of DCD and thiosulfate (K2S2O3) on changes of NH4+-N, nitrification inhibition and N recovery in a latosolic red soil. An incubation experiment was conducted with four treatments of control (CK), N, N+DCD, and N+K2S2O3. Soil samples were collected periodically over 50 d to determine concentrations of mineral N, and the amoA gene abundance of ammonia monooxygenase (AMO) for ammonia-oxidizing bacteria (AOB) was estimated by qPCR after 10 d incubation. In the N treatment, 67.8% of the applied N as NH4+-N disappeared from the mineral N pool and only 2.7% and 30.8% of the applied N was accumulated as NO2--N and NO3--N, respectively. Addition of DCD and thiosulfate to the soil prevented NH4+-N disappearance by 63.0% and 13.6%, respectively. DCD suppressed the production of NO2--N by 97.41%, whereas thiosulfate increased accumulation of NO2--N by 14.6%. Application of N along with DCD and thiosulfate inhibited nitrification, respectively, by 72.6% and 33.1%, resulting in the delay of the nitrification process for 30 days and 10 days, respectively. Apparent N recovery in N treatment was 66.2%, which increased by 55.2% and 4.8% by DCD and thiosulfate, respectively. Numbers of AOB amoA gene copy was significantly inhibited by both DCD and thiosulfate, and the stronger inhibition induced by DCD than thiosulfate was recorded. Results indicated that both DCD and thiosulfate were effective inhibitors for NH4+-N oxidation, NO3--N production, mineral N losses and AOB growth. DCD showed a more pronounced effect on nitrification inhibition than thiosulfate.

Induced accumulation of Au, Ag and Cu in Brassica napus grown in a mine tailings with the inoculation of Aspergillus niger and the application of two chemical compounds

This study evaluated the ability of Brassica napus for extracting gold (Au), silver (Ag) and copper (Cu) from a mine tailings, with the inoculation of two Aspergillus niger strains, and the application of ammonium thiocyanate (NH₄SCN) or ammonium thiosulfate [(NH₄)₂S₂O₃]. After seven weeks of growth inoculated or non-inoculated plants were applied with 1 or 2 g kg^-1 of either NH₄SCN or (NH₄)₂S₂O₃, respectively. Eight days after the application of the chemical compounds, plants were harvested for determining the total dry biomass, and the content of Au, Ag, and Cu in plant organs. Application of (NH₄)₂S₂O₃ or NH₄SCN resulted in enhanced Au-accumulation in stems (447% and 507%, respectively), while either (NH₄)₂S₂O₃+Aspergillus, or NH₄SCN increased the Au-accumulation in roots (198.5% and 404%, respectively) when compared to the control. Treatments with (NH₄)₂S₂O₃ or (NH₄)₂S₂O₃+Aspergillus significantly increased (P ≤ 0.001) the accumulation of Ag in leaves (677% and 1376%, respectively), while NH₄SCN + Aspergillus, and (NH₄)₂S₂O₃ enhanced the accumulation in stems (7153% and 6717.5%). The Ag-accumulation in roots was stimulated by NH₄SCN+ Aspergillus, and (NH₄)₂S₂O₃+ Aspergillus (132.5% and 178%, respectively), when compared to the control. The combination of NH₄SCN+Aspergillus significantly enhanced the Cu-accumulation in leaves (228%); whereas NH₄SCN+ Aspergillus, or (NH₄)₂S₂O₃+ Aspergillus resulted in greater accumulation of Cu in stems (1233.5% and 1580%, respectively) than the control. Results suggest that either NH₄SCN or (NH₄)₂S₂O₃ (with or without Aspergillus) improved the accumulation of Au and Ag by B. napus. Accumulation of Au and Ag in plant organs overpassed the hyperaccumulation criterion (> 1 mg kg^-1 of plant biomass); whereas Cu-accumulation in stems and roots also overpassed such criterion (> 1000 mg kg^-1) by applying either NH₄SCN or (NH₄)₂S₂O₃ + A. niger.

DYNAMICS OF INDICATORS OF ANTIOXIDANT PROTECTION IN RESPONSE TO THE APPLICATION OF SODIUM POLY-(2.5- DIHYDROXYPHENILEN)-4- THIOSULFATE ACID IN EXPERIMENTAL ACUTE KIDNEY INJURY

The purpose of the study is to establish the effect of the investigated drug PDT-Na on the parameters of free radical lipid oxidation and the system of antioxidant defence of the kidneys in rats on models of acute renal failure and gentamicin nephropathy. The studies were conducted on 96 white mature, full-grown non-linear rats of both sexes weighing 150-170 grams. The animals were divided into 16 groups (5 groups per model and one intact group): the animals of the experimental, reference and control pathology groups (1) received the corresponding nephrotoxin. In each model the groups of rats received the following treatment: experimental (2) - PDT-Na, reference - mexidol (3), hofitol - (4) and thiotriazolin (5). The results of the study show that under the conditions of acute kidney injury the PDT-Na assists to reduce the primary intermediates - diene conjugates and secondary intermediates of lipid peroxidation - TBA-reactive products, activation of enzymes of catalase antioxidant defence and superoxide dismutase and accumulation to the almost intact level of GSH endogenous antioxidant.The abovementioned information indicates that the drug of the pharmacological group - antihypoxicant PDT-Na with previously established nephroprotective activity has shown antioxidant, antiradical and cytoprotective properties during the experiment. This is a promising drug for complex treatment of kidney diseases.

Assessing the efficacy of aqueous garlic extract, sodium nitrite and sodium thiosulfate against prolonged oral cyanide exposure in rabbits

This study was aimed to compare the efficacy of aqueous garlic extract, sodium nitrite (SNT), sodium thiosulfate (STS) and hydroxocobalamin against oral cyanide exposure in rabbits. For this purpose, forty two adult male rabbits were divided randomly into 7 groups of 6 animals (A-G) each. Rabbits in group A were offered feed only and served as negative control, while the rabbits in group B received feed plus potassium cyanide (KCN) at 3mg/kg orally and were kept as positive control. Animals in group C received feed, KCN and intraperitoneal injection (IP) of aqueous garlic extract at 500mg/kg. Rabbits in group D were given feed, KCN and IP injection of STS at 600mg/kg. Members in group E received feed, KCN and IP injection of both aqueous garlic extract at 500mg/kg and SNT at 20mg/kg. Animals in group F were given feed, KCN and IP injection of both STS at 600mg/kg and SNT at 20mg/kg, while the rabbits in group G received feed, KCN and IP injection of hydroxocobalamin at 300mg/kg. The treatments were given to respective groups for 40 days. The efficacy of the antidotes was measured on the basis of changes in biochemical profile of rabbits in each group. In this study, hydroxocobalamin was found to be significantly more effective cyanide (CNI) antidote than garlic, STS, SNT plus garlic extract, or SNT and STS, either alone or in combination. A combination of SNT and garlic extract was the second most effective CNI antidote. The efficacy of garlic alone was significantly higher than STS alone or in combination with SNT. The efficacy of combined SNT and STS was superior to STS alone in treating rabbits with CNI toxicity. In conclusion, aqueous garlic extract alone or in combination with STS can effectively be used against cyanide toxicity.

Screening of chelating ligands to enhance mercury accumulation from historically mercury-contaminated soils for phytoextraction

Screening of optimal chelating ligands which not only have high capacities to enhance plant uptake of mercury (Hg) from soil but also can decrease bioavailable Hg concentration in soil is necessary to establish a viable chemically-assisted phytoextraction. Therefore, Brassica juncea was exposed to historically Hg-contaminated soil (total Hg, 90 mg kg^-1) to investigate the efficiency of seven chelating agents [ammonium thiosulphate, sodium thiosulphate, ammonium sulfate, ammonium chloride, sodium nitrate, ethylenediaminetetraacetic acid (EDTA), and sodium sulfite] at enhancing Hg phytoextraction; the leaching of bioavailable Hg caused by these chelating agents was also investigated. The Hg concentration in control (treated with double-distilled water) plant tissues was below 1 mg kg^-1. The remarkably higher Hg concentration was found in plants receiving ammonium thiosulphate and sodium sulfite treatments. The bioaccumulation factors and translocation factors of ammonium thiosulphate and sodium sulfite treatments were significantly higher than those of the other treatments. The more efficient uptake of Hg by plants upon treatment with ammonium thiosulphate and sodium sulfite compared to the other treatments might be explained by the formation of special Hg-thiosulphate complexes that could be preferentially taken up by the roots and transported in plant tissues. The application of sulfite significantly increased bioavailable Hg concentration in soil compared with that in initial soil and control soil, whereas ammonium thiosulphate significantly decreased bioavailable Hg concentration. The apparent decrease of bioavailable Hg in ammonium thiosulphate-treated soil compared with that in sodium sulfite-treated soil might be attributable to the unstable Hg-thiosulphate complexes formed between thiosulphate and Hg; they could react to produce less bioavailable Hg in the soil. The results of this study indicate that ammonium thiosulphate may be an optimal chelating ligand for phytoextraction due to its great potential to enhance Hg accumulation in plants while decreasing bioavailable Hg concentration in the soil.

Overexpression of a Chitinase Gene from Trichoderma asperellum Increases Disease Resistance in Transgenic Soybean

In the present study, a chi gene from Trichoderma asperellum, designated Tachi, was cloned and functionally characterized in soybean. Firstly, the effects of sodium thiosulfate on soybean Agrobacterium-mediated genetic transformation with embryonic tip regeneration system were investigated. The transformation frequency was improved by adding sodium thiosulfate in co-culture medium for three soybean genotypes. Transgenic soybean plants with constitutive expression of Tachi showed increased resistance to Sclerotinia sclerotiorum compared to WT plants. Meanwhile, overexpression of Tachi in soybean exhibited increased reactive oxygen species (ROS) level as well as peroxidase (POD) and catalase (SOD) activities, decreased malondialdehyde (MDA) content, along with diminished electrolytic leakage rate after S. sclerotiorum inoculation. These results suggest that Tachi can improve disease resistance in plants by enhancing ROS accumulation and activities of ROS scavenging enzymes and then diminishing cell death. Therefore, Tachi represents a candidate gene with potential application for increasing disease resistance in plants.

Sodium Thiosulfate Prevents Chondrocyte Mineralization and Reduces the Severity of Murine Osteoarthritis

Objectives

Calcium-containing crystals participate in the pathogenesis of OA. Sodium thiosulfate (STS) has been shown to be an effective treatment in calcification disorders such as calciphylaxis and vascular calcification. This study investigated the effects and mechanisms of action of STS in a murine model of OA and in chondrocyte calcification.

Methods

Hydroxyapatite (HA) crystals-stimulated murine chondrocytes and macrophages were treated with STS. Mineralization and cellular production of IL-6, MCP-1 and reactive oxygen species (ROS) were assayed. STS's effects on genes involved in calcification, inflammation and cartilage matrix degradation were studied by RT-PCR. STS was administered in the menisectomy model of murine OA, and the effect on periarticular calcific deposits and cartilage degeneration was investigated by micro-CT-scan and histology.

Results

In vitro, STS prevented in a dose-dependent manner calcium crystal deposition in chondrocytes and inhibited Annexin V gene expression. In addition, there was a reduction in crystal-induced IL-6 and MCP-1 production. STS also had an antioxidant effect, diminished HA-induced ROS generation and abrogated HA-induced catabolic responses in chondrocytes. In vivo, administration of STS reduced the histological severity of OA, by limiting the size of new periarticular calcific deposits and reducing the severity of cartilage damage.

Conclusions

STS reduces the severity of periarticular calcification and cartilage damage in an animal model of OA via its effects on chondrocyte mineralization and its attenuation of crystal-induced inflammation as well as catabolic enzymes and ROS generation. Our study suggests that STS may be a disease-modifying drug in crystal-associated OA.

Bioavailability of silver and silver sulfide nanoparticles to lettuce (Lactuca sativa): Effect of agricultural amendments on plant uptake

Silver nanoparticles (AgNPs) can enter terrestrial systems as sulfidised AgNPs (Ag2S-NPs) through the application of biosolids to soil. However, the bioavailability of Ag2S-NPs in soils is unknown. The two aims of this study were to investigate (1) the bioavailability of Ag to lettuce (Lactuca sativa) using a soil amended with biosolids containing Ag2S-NPs and (2) the effect of commonly used agricultural fertilisers/amendments on the bioavailability of Ag, AgNPs and Ag2S-NPs to lettuce. The study used realistic AgNP exposure pathways and exposure concentrations. The plant uptake of Ag from biosolids-amended soil containing Ag2S-NPs was very low for all Ag treatments (0.02%). Ammonium thiosulfate and potassium chloride fertilisation significantly increased the Ag concentrations of plant roots and shoots. The extent of the effect varied depending on the type of Ag. Ag2S-NPs, the realistic form of AgNPs in soil, had the lowest bioavailability. The potential risk of AgNPs in soils is low; even in the plants that had the highest Ag concentrations (Ag(+)+thiosulfate), only 0.06% of added Ag was found in edible plant parts (shoots). Results from the study suggest that agricultural practises must be considered when carrying out risk assessments of AgNPs in terrestrial systems; such practises can affect AgNP bioavailability.

Remediation of Cr(VI) contaminated soil using long-duration sodium thiosulfate supported by micro-nano networks

In this work, a long-duration remediation agent (LRA) on hexavalent chromium (Cr(VI)) was developed using sodium thiosulfate (ST) supported by attapulgite (ATP) micro-nano networks induced through high-energy electron beam (HEEB) irradiation. The ATP networks could effectively reduce the leaching amount of Cr(VI) in soil. More importantly, the ATP networks could significantly control the leaching behavior of ST, and then prolong the duration and increase the reduction efficiency of ST on Cr(VI). As a result, LRA displayed high performance on controlling the migration of Cr(VI) and reducing Cr(VI) to Cr(III). Additionally, pot experiment indicated that LRA could effectively decrease the absorbed amount of Cr(VI) in corn, and reduce the inhibition effect of Cr(VI) on the growth of corn. Therefore, this work could provide a facile approach to remediate the Cr(VI)-contaminated soil and lower the harmful effect of Cr(VI) on crop.

Effects of phosphate and thiosulphate on arsenic accumulation in the species Brassica juncea

Arsenic (As) is recognized as a toxic pollutant in soils of many countries. Since phosphorus (P) and sulphur (S) can influence arsenic mobility and bioavailability, as well as the plant tolerance to As, phytoremediation techniques employed to clean-up As-contaminated areas should consider the interaction between As and these two nutrients. In this study, the bioavailability and accumulation of arsenate in the species Brassica juncea were compared between soil system and hydroponics in relation to P and S concentration of the growth substrate. In one case, plants were grown in pots filled with soil containing 878 mg As kg(-1). The addition of P to soil resulted in increased As desorption and significantly higher As accumulation in plants, with no effect on growth. The absence of toxic effects on plants was likely due to high S in soil, which could efficiently mitigate metal toxicity. In the hydroponic experiment, plants were grown with different combinations of As (0 or 100 μM) and P (56 or 112 μM). S at 400 μM was also added to the nutrient solution of control (-As) and As-treated plants, either individually or in combination with P. The addition of P reduced As uptake by plants, while high S resulted in higher As accumulation and lower P content. These results suggest that S can influence the interaction between P and As for the uptake by plants. The combined increase of P and S in the nutrient solution did not lead to higher accumulation of As, but enhanced As translocation from the root to the shoot. This aspect is of relevance for the phytoremediation of As-contaminated sites.

Conifer somatic embryogenesis: improvements by supplementation of medium with oxidation-reduction agents

A major barrier to the commercialization of somatic embryogenesis technology in loblolly pine (Pinus taeda L.) is recalcitrance of some high-value crosses to initiate embryogenic tissue (ET) and continue early-stage somatic embryo growth. Developing initiation and multiplication media that resemble the seed environment has been shown to decrease this recalcitrance. Glutathione (GSH), glutathione disulfide (GSSG), ascorbic acid and dehydroascorbate analyses were performed weekly throughout the sequence of seed development for female gametophyte and zygotic embryo tissues to determine physiological concentrations. Major differences in stage-specific oxidation-reduction (redox) agents were observed. A simple bioassay was used to evaluate potential growth-promotion of natural and inorganic redox agents added to early-stage somatic embryo growth medium. Compounds showing statistically significant increases in early-stage embryo growth were then tested for the ability to increase initiation of loblolly pine. Low-cost reducing agents sodium dithionite and sodium thiosulfate increased ET initiation for loblolly pine and Douglas fir (Mirb) Franco. Germination medium supplementation with GSSG increased somatic embryo germination. Early-stage somatic embryos grown on medium with or without sodium thiosulfate did not differ in GSH or GSSG content, suggesting that sodium thiosulfate-mediated growth stimulation does not involve GSH or GSSG. We have developed information demonstrating that alteration of the redox environment in vitro can improve ET initiation, early-stage embryo development and somatic embryo germination in loblolly pine.

The role of silver nano-particles and silver thiosulfate on the longevity of cut carnation (Dianthus caryophyllus) flowers

The purpose of this study was to evaluate the efficacy of silver nano-particles (SNP) and silver thiosulfate (STS) in extending the vase life of cut carnation (Dianthus caryophyllus L. cv. 'Tempo') flowers. Pulse treatments of SNP @ 0, 5, 10 and 15 mg l(-1) and STS @ 0, 0.1, 0.2 and 0.3 mM were administered to carnation flowers for 24 hr. The longest vase life (16.1 days) was observed in flowers treated with 15 mg l(-1) of SNP + 0.2 mM STS. The least chlorophyll was destroyed in flowers treated with 15 mg I(-1) of SNP + 0.3 mM STS. Our findings showed that the 15 mg l(-1) SNP treatment inhibited bacterial growth in the preservative solution. The control flowers bloomed faster than the treated flowers. The maximum peroxidase activity and the minimum lipid peroxidation were obtained in cut flowers that were treated with 15 mg l(-1) of SNP and 0.3 mM STS. Overall, results of the study revealed that SNP and STS treatment extended the longevity of cut carnation 'Tempo' flowers by reducing oxidative stress, improving anti-oxidant system, reducing bacterial populations and delaying flowering.

Calciphylaxis treated with sodium thiosulfate: report of two cases

Although traditionally observed in patients with end-stage renal disease and secondary hyperparathyroidism, calciphylaxis has been reported in patients with normal renal and parathyroid function. There is no evidence-based therapy available. The use of sodium thiosulfate (STS) has been increasingly described. Herein we describe two patients who responded well to this treatment.

Quantification of the uptake of silver nanoparticles and ions to HepG2 cells

The toxic mechanism of silver nanoparticles (AgNPs) is still debating, partially because of the common co-occurrence and the lack of methods for separation of AgNPs and Ag(+) in biological matrices. For the first time, Triton-X 114-based cloud point extraction (CPE) was proposed to separate AgNPs and Ag(+) in the cell lysates of exposed HepG2 cells. Cell lysates were subjected to CPE after adding Na2S2O3, which facilitated the transfer of AgNPs into the nether Triton X-114-rich phase by salt effect and the preserve of Ag(+) in the upper aqueous phase through the formation of hydrophilic complex. Then the AgNP and Ag(+) contents in the exposed cells were determined by ICP-MS after microwave digestion of the two phases, respectively. Under the optimized conditions, over 67% of AgNPs in cell lysates were extracted into the Triton X-114-rich phase while 94% of Ag(+) remained in the aqueous phase, and the limits of detection for AgNPs and Ag(+) were 2.94 μg/L and 2.40 μg/L, respectively. This developed analytical method was applied to quantify the uptake of AgNPs to the HepG2 cells. After exposure to 10 mg/L AgNPs for 24 h, about 67.8 ng Ag were assimilated per 10(4) cells, in which about 10.3% silver existed as Ag(+). Compared to the pristine AgNPs (with 5.2% Ag(+)) for exposure, the higher ratio of Ag(+) to AgNPs in the exposed cells (10.3% Ag(+)) suggests the transformation of AgNPs into Ag(+) in the cells and/or the higher uptake rate of Ag(+) than that of AgNPs. Given that the toxicity of Ag(+) is much higher than that of AgNPs, the substantial content of Ag(+) in the exposed cells suggests that the contribution of Ag(+) should be taken into account in evaluating the toxicity of AgNPs to organisms, and previous results obtained by regarding the total Ag content in organisms as AgNPs should be reconsidered.

Non-cell-autonomous postmortem lignification of tracheary elements in Zinnia elegans

Postmortem lignification of xylem tracheary elements (TEs) has been debated for decades. Here, we provide evidence in Zinnia elegans TE cell cultures, using pharmacological inhibitors and in intact Z. elegans plants using Fourier transform infrared microspectroscopy, that TE lignification occurs postmortem (i.e., after TE programmed cell death). In situ RT-PCR verified expression of the lignin monomer biosynthetic cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase in not only the lignifying TEs but also in the unlignified non-TE cells of Z. elegans TE cell cultures and in living, parenchymatic xylem cells that surround TEs in stems. These cells were also shown to have the capacity to synthesize and transport lignin monomers and reactive oxygen species to the cell walls of dead TEs. Differential gene expression analysis in Z. elegans TE cell cultures and concomitant functional analysis in Arabidopsis thaliana resulted in identification of several genes that were expressed in the non-TE cells and that affected lignin chemistry on the basis of pyrolysis-gas chromatography/mass spectrometry analysis. These data suggest that living, parenchymatic xylem cells contribute to TE lignification in a non-cell-autonomous manner, thus enabling the postmortem lignification of TEs.

Using a plant hormone and a thioligand to improve phytoremediation of Hg-contaminated soil from a petrochemical plant

Mercury-contaminated soils from a petrochemical plant in southern Italy were investigated to assess the phytoextraction efficiency of crop plants treated with the phytohormone, cytokinine (CK foliar treatment), and with the thioligand, ammonium thiosulfate (TS, soil application). Plant biomass, evapotranspiration, Hg uptake and distribution in plant tissues following treatment were compared. Results indicate the effectiveness of CK in increasing plant biomass and the evapotranspiration rate while TS treatment promoted soil Hg solubility and availability. The simultaneous addition of CK and TS treatments increased Hg uptake and translocation in both tested plants with up to 248 and 232% in Brassica juncea (Indian mustard) and Helianthus annuus (sunflower) respectively. B. juncea was more effective in Hg uptake, whereas H. annuus gave better response regarding plant biomass production. The effectiveness of the treatments was confirmed by the calculation of Hg phytoextraction and evaluation of labile-Hg residue in the soil after plant growth. In one growing cycle the plants subject to simultaneous CK and TS treatment significantly reduced labile-Hg pools that were characterized by the soil sequential extraction, but did not significantly affect the pseudototal metal content in the soil. Results support the use of plant growth regulators in the assisted phytoextraction process for Hg-contaminated soils.

Implications of mercury speciation in thiosulfate treated plants

Mercury uptake was induced in two cultivars of Brassica juncea under field conditions using thiosulfate. Analysis was conducted to better understand the mechanism of uptake, speciation of mercury in plants, and redistribution of mercury in the soil. Plant mercury and sulfur concentrations were increased after thiosulfate treatment, and a linear correlation between mercury and sulfur was observed. Mercury may be absorbed and transported in plants as the Hg-thiosulfate complex. The majority of mercury in treated plant tissues (two cultivars) was bound to sulfur in a form similar to β-HgS (66-94%). Remaining mercury was present in forms similar to Hg-cysteine (1-10%) and Hg-dicysteine (8-28%). The formation of β-HgS may relate to the transport and assimilation of sulfate in plant tissues. Mercury-thiosulfate complex could decompose to mercuric and sulfate ions in the presence of free protons inside the plasma membrane, while sulfide ions would be produced by the assimilation of sulfate. The concomitant presence of mercuric ions and S(2-) would precipitate β-HgS. The mercury concentration in the rhizosphere decreased in the treated relative to the nontreated soil. The iron/manganese oxide and organic-bound fractions of soil mercury were transformed to more bioavailable forms (soluble and exchangeable and specifically sorbed) and taken up by plants.

[C-ring cleavage of liquiritigenin extracted from licorice roots by an oxygen-tolerant bovine rumen bacterium strain Aeroto-Niu-O16]

Aeroto-Niu-O16, an oxygen-tolerant bovine rumen bacterium, is capable of aerobically reducing isoflavones daidzein and genistein to dihydrodaidzein and dihydrogenistein through catalytic hydrogenation. In this study, it was found that bacterium strain Aeroto-Niu-O16 was able to cleavage the C-ring of liquiritigenin (LG), which is one of the main biologically active components of licorice roots, in the presence of atmospheric oxygen. LG was prepared by acid hydrolysis of the crude extract of licorice roots. The metabolite of LG obtained in strain Aeroto-Niu-O16 was identified as davidigenin (DG) based on the data of UV, MS, 1H and 13C NMR. The maximal concentration of LG that the strain Aeroto-Niu-O16 was able to transform effectively was 0.8 mmol x L(-1) and the average productivity of the metabolite DG was 71.7%. Furthermore, when 0.1% (m/v) of L-cysteine or sodium thiosulfate was added in the cultural medium, the average bioconversion rate of LG was increased from 71.7% to 78.3% and 77.2%, respectively. The in vitro antioxidant investigation showed that 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of DG was significantly or extremely significantly higher than that of LG at the concentrations from 0.2 mmol x L(-1) to 1.6 mmol x L(-1). We discoverd for the first time that LG can be converted to DG, which has stronger and wider biological activities, through microbial biotransformation method.

Ethylene is involved in pistil fate by modulating the onset of ovule senescence and the GA-mediated fruit set in Arabidopsis

BACKGROUND

Ovule lifespan is an important factor in determining the ability to set fruits and produce seeds. Once ovule senescence is established, fruit set capacity in response to gibberellins (GAs) is lost. We aimed to elucidate whether ethylene plays a role in controlling ovule senescence and the fruit set response in Arabidopsis.

RESULTS

Ethylene response inhibitors, silver thiosulphate (STS) and 1-methylcyclopropene (1-MCP), were able to delay the loss of pistil response to GA(3). In addition, ethylene insensitive mutants ein2-5 and ein3-1 showed delayed loss of pistil response, as in plants treated with STS and 1-MCP, while constitutive mutant ctr1-1 displayed premature loss of response. The analysis of the expression of ethylene biosynthesis genes suggests that ethylene is synthesised in ovules at the onset of ovule senescence, while a transcriptional meta-analysis also supports an activated ethylene-dependent senescence upon the establishment of ovule senescence. Finally, a SAG12:GUS reporter line proved useful to monitor ovule senescence and to directly demonstrate that ethylene specifically modulates ovule senescence.

CONCLUSIONS

We have shown that ethylene is involved in both the control of the ovule lifespan and the determination of the pistil/fruit fate. Our data support a role of the ovule in modulating the GA response during fruit set in Arabidopsis. A possible mechanism that links the ethylene modulation of the ovule senescence and the GA3-induced fruit set response is discussed.

Effects of sodium thiosulfate on vascular calcification in end-stage renal disease: a pilot study of feasibility, safety and efficacy

BACKGROUND AND OBJECTIVES

Vascular calcification is a major contributor to morbidity and mortality in hemodialysis. The objective of this pilot study was to determine the feasibility, safety and efficacy of sodium thiosulfate (STS) in the progression of vascular calcification in hemodialysis patients.

METHODS

Chronic hemodialysis patients underwent a battery of cardiovascular tests. Those with coronary artery calcium (Agatston scores >50) received intravenous STS after each dialysis for 5 months (n = 22) and the tests were repeated. Changes in MDCT-determined calcification were assessed as the mean annualized rate of change in 3 vascular beds (coronary, thoracic and carotid arteries) and in L1-L2 vertebral bone density.

RESULTS

Although individual analyses showed coronary artery calcification progression in 14/22 subjects, there was no progression in the mean annualized rate of change of vascular calcification in the entire group. The L1-L2 vertebral bone density showed no changes. There were no correlations between rates of progression of vascular calcification and phosphorus, fetuin or C-reactive protein levels. Changes in coronary artery calcification scores correlated with those of the thoracic aorta.

CONCLUSION

STS treatment is feasible, appears safe and may decrease the rate of progression of vascular calcification in hemodialysis patients. A large, randomized, controlled trial is warranted.

[Antioxidant properties of some sulfur-containing substances]

The antioxidant properties of sulfur-containing substances have been experimentally studied in vitro. Unithiol exhibits a wide spectrum us radicals. For this reason, unithiol can be considered, along with ascorbic acid, as a universal drug for the reduction of free radical reactions.

Control of in vitro rooting and plant development in Corymbia maculata by silver nitrate, silver thiosulfate and thiosulfate ion

Plant regeneration and transformation in vitro is often improved by adding silver ion (Ag(+)) to the culture media as AgNO(3) or silver thiosulfate (STS). Ag(+) reacts with substances to form insoluble precipitates, while thiosulfate (S(2)O(3) (2-)) interferes with these reactions. We studied the implications of silver precipitation and S(2)O(3) (2-) in the medium for culture development by (1) examining formation of Ag(+) precipitates from AgNO(3) versus STS in agar gels and their possible dependence on agar type; (2) comparing Corymbia maculata culture responses to AgNO(3) and STS and determining which better suits control of culture development; (3) clarifying whether STS-dependent alterations in culture development are due to Ag(+) alone or also to a separate influence of S(2)O(3) (2-). Silver precipitates appeared in aqueous gels of four agar brands supplemented with AgNO(3), but not in Phytagel(™), which remained transparent. No precipitation was observed in gels with STS. Indole-3-butyric acid (IBA)-mediated adventitious root induction and shoot growth were higher in C. maculata shoot tips cultured on gels with STS versus AgNO(3) (6-25 μM Ag(+)). IBA-treated shoot tips exhibited enhanced adventitious root regeneration, accelerated root elongation, increased frequency of lateral root formation, and stimulated shoot growth mediated by 100-250 μM sodium thiosulfate (Na(2)S(2)O(3)) in medium without Ag(+). The potency of S(2)O(3) (2-) in facilitating culture development has never been recognized. It is inferred that superiority of STS in stimulating multiple responses of C. maculata culture results from sustained biological activity of Ag(+) through prevention of its precipitation, and from impact of S(2)O(3) (2-) on cell differentiation and growth.

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Tetranychus evansi Baker & Pritchard is an important pest of solanaceous plants, including tomatoes. This mite is characterized by a high reproductive rate, which leads to high population growth in a short period of time causing important economic damage. Control of T. evansi is mainly through synthetic acaricides. In searching for environmentally friendly control measures, we evaluated the efficiency of alternative products to control T. evansi on tomato plants under greenhouse conditions. The products tested were lime sulphur and neem based products. We first estimated the lethal concentration (LC) and instantaneous rate of increase (r i) of T. evansi exposed to different product concentrations in laboratory conditions, and later tested the efficacy of LC95 and the concentrations that restrained mite population growth (r i = 0) in greenhouse conditions. The following treatments were repeated three times: NeemPro (81.0 and 71.6 mg a.i./l), Natuneem (31.1 and 20.4 mg ai/l), Organic Neem (39.1 and 30.4 mg a.i./l), lime sulphur (1.0 and 0.6%) and water (control). For all products, control provided by LC95 was higher than provided for lower concentrations (r i = 0) one day after spraying. However, after five days, for both concentrations, the percentage of T. evansi population reduction was superior to 95% and increased over time. Only plants sprayed with Natuneem (31.1 mg a.i./l) showed symptoms of phytotoxicity. Lime sulphur and neem based products, applied in appropriate concentrations and formulations, bear out as a viable alternative to control T. evansi on tomato plants.

The effect of Tween 80 on eggshell permeabilization in Galleria mellonella (L.) (Lepidoptera, Pyralidae)

The development of a species-specific protocol for dechorionation and permeabilization of insect eggs is a necessary prerequisite to cryopreserve the embryos. Here we tested different procedures based on heptane or the surfactant Tween 80 as an alternative to alkane, evaluating their efficacy and toxicity on the early (24 h post-oviposition) and late (75 h post-oviposition) stage embryos. Heptane efficiently permeabilized the eggs of G. mellonella but the hatching rate ranged from 0.1 to 4.2 percent in the early stage and from 4.3 to 11.2 percent in the late stage. The embryos treated with 1.25 percent NaOCl + 0.08 percent Tween 80 for 2 min showed the same shrinkage and reswelling percentages as eggs exposed to heptane for 10 sec, with a significantly higher hatching percentage in the early (68.2 +/- 1.5 percent) and late stages (22.4 +/- 3.7 percent). Thus, 0.08 percent Tween 80 allows sufficient permeabilization of G. mellonella embryos without the high toxicity of alkane.

Protective role of alpha-ketoglutarate against massive doses of cyanide in rats

Cyanide is a highly toxic cellular poison that requires immediate and aggressive treatments. Combination of sodium nitrite (SN) and sodium thiosulfate (STS) is the treatment of choice but oral treatment of alpha-ketoglutarate (A-KG) has also been shown to significantly antagonize cyanide poisoning in laboratory animals. This study reports the efficacy of various treatment regimens as: (i) repeated doses of A-KG after simultaneous treatment of A-KG and STS, (ii) repeated doses of A-KG after pre-treatment of SN, STS and A-KG, (iii) repeated doses of STS after pre-treatment of SN, STS and A-KG, and (iv) repeated doses of A-KG and STS after pretreatment of SN, STS and A-KG on mortality of female rats exposed to massive doses of potassium cyanide. A maximum of 40-folds protection was observed when A-KG at 1.0 g kg(-1) after 2 hr and 0.5 g kg(-1) after 4 hr was repeated following the pre-treatment of SN (0.025 g kg(-1); subcutaneous;-45 min), STS (1.0 g kg(-1); intraperitoneal; -15 min) andA-KG (2.0 g kg(-1); oral; -10 min). Similar protection was also conferred by repeating 0.5 g kg(-1) each of A-KG and STS 2 hr after pre-treatment of SN, STS and A-KG. Also, 38-folds protection after simultaneous administration of 20 g kg(-1) A-KG and 1.0 g kg(-1) STS, followed by 2.0 g kg(-1) A-KG after 2 hr was noteworthy The results indicate that repeated treatment of A-KG alone after simultaneous treatment of A-KG and STS or repeated treatment of A-KG alone or with STS after pre-treatment of A-KG, SN and STS have immense potential in challenging extremely high doses of cyanide as compared to the antidotes given once. The study has implications in the development of A-KG as an alternate treatment for cyanide poisoning.

Lethal, sublethal, and behavioral effects of sulfur-containing products in bioassays of three species of orchard mites

The effects of three sulfur products (calcium polysulfide [= lime sulfur], dry flowable sulfur, and ammonium thiosulfate, a plant nutrient), were tested in bioassays against a predatory mite, Galandromus occidentalis (Nesbitt), and two species of tetranychid (pest) mites, twospotted spider mite (Tetranychus urticae Koch) and European red mite [Panonychus ulmi (Koch)]. Calcium polysulfide and ammonium thiosulfate were acutely toxic on contact to adult females of all three mite species, causing 58-100% mortality in 48 h. Dry flowable sulfur, in contrast, was nontoxic to adults of all three species. Fresh residues of the sulfur products were essentially nontoxic to females of G. occidentalis and T. urticae. Galandromus occidentalis consumed 8.2 and 4.0x fewer prey contaminated with residues of calcium polysulfide and ammonium thiosulfate; dry flowable sulfur had no effect on prey consumption. Higher posttreatment temperatures (32 versus 18 degrees C) did not affect the toxicity of dry flowable sulfur to G. occidentalis and T. urticae. The toxic effect of the sulfur products was not related to the concentration of elemental S but rather to some intrinsic characteristic of the compound itself. There were substantial differences in the responses of different stages of G. occidentalis. Residues that were nontoxic to adult females were highly toxic to hatching larvae, including those of dry flowable sulfur. In addition, all three products were highly repellent to adult female G. occidentalis. The lethal effect of calcium polysulfide on larvae was still present when the laboratory-aged residues on bean leaves were 8-9 d old. Field-aged residues on apple (Malus spp.) leaves were highly toxic (89% mortality) after 7 d, but mortality declined to 50 and 17% after 14 and 22 d, respectively. The increasing use of sulfur-containing products is detrimental to predatory mites and may play a role in the diminishing effectiveness of integrated mite control in Washington apple orchards.

[Influence of hydrogen sulfide, dithionite, sulfite, thiosulfate and sulfate anions on human platelet aggregation]

The influence of hydrogen sulfide, dithionite, sulfite, thiosulfate, and sulfate anions on human platelet aggregation was investigated in vitro. It was established that sulfite, thiosulfate, and sulfate did not influence the platelet aggregation induced by ADP, collagen, or epinephrine in the concentrations range 10-1000 microM. Hydrogen sulfide and dithionite inhibited platelet aggregation induced by ADF or collagen in a dose-dependent manner. The action of hydrogen sulfide began in concentration of 100 microM and the action of dithionite began in concentration of 1000 microM. They did not influence epinephrine-induced platelet aggregation.

Delayed sodium thiosulphate administration reduces cisplatin efficacy on mouse EMT6 tumour cells in vitro

OBJECTIVE

To determine whether simultaneous and/or delayed administration of sodium thiosulphate (STS) affects the oncologic effect of cisplatin or cisdiaminedichloroplatinum (CDDP) in EMT6 tumour cells in vitro.

SETTING

Cell biology research laboratory.

METHODS

Clonogenic assays of EMT6 tumour cells with CDDP alone, CDDP plus simultaneous STS, and CDDP plus a 4-hour delay of STS were performed. Growth fractions under these three conditions were compared.

RESULTS

Tumour growth was statistically significantly increased when CDDP and STS were administered compared with CDDP alone. There was no statistically significant difference between simultaneous and 4-hour delay of STS administration. We conclude that in EMT6 cells, either simultaneous administration or a 4-hour delay of STS administration significantly decreases CDDP efficacy.

CONCLUSION

STS adversely affects CDDP's oncologic efficacy in EMT6 cell cultures in vitro.

Cardioprotective role of sodium thiosulfate on chronic heart failure by modulating endogenous H2S generation

BACKGROUND/AIMS

Sodium thiosulfate (STS) has been shown to be an antioxidant and calcium solubilizer, but the possible role of STS in dysfunctional ventricles remains unknown. Here, we assessed the effects of STS in the failing heart.

METHODS

Heart failure was created by an arteriovenous fistula (AVF). Mice were divided into 4 groups: sham, AVF, sham + STS, and AVF + STS. STS (3 mg/ml) was supplemented with drinking water for 6 weeks in the appropriate surgery groups after surgery.

RESULTS

M-mode echocardiograms showed ventricular contractile dysfunction with reduced aortic blood flow in AVF mice, whereas STS treatment prevented the decline in cardiac function. Ventricular collagen, MMP-2 and -9, and TIMP-1 were robustly increased with a decreasing trend in adenylate cyclase VI expression; however, STS supplementation reversed these effects in AVF mice. Among 2 enzymes that produce endogenous hydrogen sulfide (H(2)S), cystathionine-gamma-lyase (CSE) expression was attenuated in AVF mice with no changes in cystathionine-beta-synthase (CBS) expression. In addition, reduced production of H(2)S in AVF ventricular tissue was normalized with STS supplementation. Moreover, cardiac tissues were more responsive to H(2)S when AVF mice were supplemented with STS compared to AVF alone.

CONCLUSIONS

These results suggested that STS modulated cardiac dysfunction and the extracellular matrix, in part, by increasing ventricular H(2)S generation.

Ethylene and not embolism is required for wound-induced tylose development in stems of grapevines

The pruning of actively growing grapevines (Vitis vinifera) resulted in xylem vessel embolisms and a stimulation of tylose formation in the vessels below the pruning wound. Pruning was also followed by a 10-fold increase in the concentration of ethylene at the cut surface. When the pruning cut was made under water and maintained in water, embolisms were prevented, but there was no reduction in the formation of tyloses or the accumulation of ethylene. Treatment of the stems with inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine) and/or action (silver thiosulfate) delayed and greatly reduced the formation of tyloses in xylem tissue and the size and number of those that formed in individual vessels. Our data are consistent with the hypotheses that wound ethylene production is the cause of tylose formation and that embolisms in vessels are not directly required for wound-induced tylosis in pruned grapevines. The possible role of ethylene in the formation of tyloses in response to other stresses and during development, maturation, and senescence is discussed.