Tellurite and Selenite: how can these two oxyanions be chemically different yet so similar in the way they are transformed to their metal forms by bacteria?

This opinion review explores the microbiology of tellurite, TeO32− and selenite, SeO32− oxyanions, two similar Group 16 chalcogen elements, but with slightly different physicochemical properties that lead to intriguing biological differences. Selenium, Se, is a required trace element compared to tellurium, Te, which is not. Here, the challenges around understanding the uptake transport mechanisms of these anions, as reflected in the model organisms used by different groups, are described. This leads to a discussion around how these oxyanions are subsequently reduced to nanomaterials, which mechanistically, has controversies between ideas around the molecule chemistry, chemical reactions involving reduced glutathione and reactive oxygen species (ROS) production along with the bioenergetics at the membrane versus the cytoplasm. Of particular interest is the linkage of glutathione and thioredoxin chemistry from the cytoplasm through the membrane electron transport chain (ETC) system/quinones to the periplasm. Throughout the opinion review we identify open and unanswered questions about the microbial physiology under selenite and tellurite exposure. Thus, demonstrating how far we have come, yet the exciting research directions that are still possible. The review is written in a conversational manner from three long-term researchers in the field, through which to play homage to the late Professor Claudio Vásquez.

Biosynthesis of spherical selenium nanoparticles with halophilic Bacillus subtilis subspecies stercoris strain XP for inhibition of strawberry pathogens / 生物工程学报

Biosynthesis of nanomaterials has attracted much attention for its excellent characteristics such as low energy consumption, high safety, and environmental friendliness. As we all know, the toxic selenite can be transformed into higher-value nanomaterials by using bacteria. In this study, nano-selenium was synthesized by halophilic Bacillus subtilis subspecies stercoris strain XP in LB medium supplemented with selenite (electron acceptor). The physicochemical characteristics of nano-selenium were analyzed by scanning electron microscope (SEM), X-ray energy dispersive spectral analysis (EDAX), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). Meanwhile, the antifungal activity of nano-selenium to strawberry pathogens (fusarium wilt, erythema, and purple spot fungi) was determined. The products from reduction of selenite by strain XP was amorphous spherical selenium nanoparticles (SeNPs) with a diameter range of 135-165 nm. The production of SeNPs was positively correlated with time (0-48 h) and no changes were observed on cell morphology. Selenium was dominant in the surface of SeNPs where the organic elements (C, O, N, and S) existed at the same time. SeNPs were coated with biomolecules containing functional groups (such as -OH, C=O, N-H, and C-H) which were associated with the stability and bioactivity of particles. Although the highest concentration of SeNPs had significant (P<0.05) inhibitory effects on three strains of strawberry pathogens, antifungal activity to erythema and fusarium wilt pathogenic fungi was higher than that to purple spot pathogenic fungi from strawberry. In conclusion, strain XP not only has strong tolerance to high salt stress, but can be also used to synthesize biological SeNPs with good stability and biological activity. Thus, the strain XP has bright perspectives and great potential advantage in pathogens control and green selenium-rich strawberry planting as well as other fields.

Characteristics of selenium nanoparticles synthesized by cell-free supernatant Cupriavidus sp. SHE / 生物工程学报

In recent years, selenium nanoparticles (SeNPs) have been widely used in many fields such as nanotechnology, biomedicine and environmental remediation due to their good electrical conductivity, photothermal properties and anticancer properties. In this study, the cell-free supernatant, whole cell and the cell-free extracts of the strain Cupriavidus sp. SHE were used to synthesize SeNPs, and several methods were applied to analyze the crystal structure and surface functional groups of the nanoparticles. Finally, Pseudomonas sp. PI1 (G⁺) and Escherichia coli BL21 (G⁻) were selected to investigate the antibacterial properties of SeNPs. Cell-free supernatant, whole cell and cell-free extracts of the strain could synthesize SeNPs. As for the cell-free supernatant, selenite concentration of 5 mmol/L and pH=7 were favorable for the synthesis of SeNPs. TEM images show that the average size of nanospheres synthesized by the supernatant was 196 nm. XRD analysis indicates the hexagonal crystals structure of SeNPs. FTIR and SDS-PAGE confirmed the proteins bound to the surfaces of SeNPs. SeNPs synthesized by cell-free supernatant showed no antimicrobial activities against Pseudomonas sp. PI1 and Escherichia coli BL21 (DE3). These results suggest that proteins played an important role in biotransformation of SeNPs in an eco-friendly process, and SeNPs synthesized in this study were non-toxic and biologically compatible, which might be applied in other fields in the future.

Selenium supplementation in pediatric patients using parenteral nutrition: Is it time to do something? / Suplementação de selênio nos pacientes pediátricos em uso de nutrição parenteral: é hora de fazer algo?

Summary Objective: To analyze the nutritional status of selenium and verify the effect of its supplementation in pediatric patients during 14 days of parenteral nutrition (PN). Method: This is a series of cases with patients followed for two weeks while using PN. Data collection was performed at the beginning (T0), in the 7th (T1) and 14th days of PN (T2). The supplemented group received 2 µg/kg/day of selenous acid. Weight and height were measured for nutritional status assessment. Tests requested: plasma selenium, albumin, pre-albumin, C-reactive protein (CRP), total cholesterol and HDL-cholesterol. Results: Fourteen (14) patients with inflammatory process and with low or very low weight for their ages were evaluated. In both groups (with and without supplementation), all patients had low selenium levels. Median plasma selenium concentrations were 17.4 µg/L (T0), 23.0 µg/L (T1) and 20.7 µg/L (T2). Increase and reduction of selenium occurred both in patients with high CRP and in those presenting normalization of this parameter. Conclusion: Lower plasma selenium levels have been detected since the start of the research and supplementation (2 µg/kg/day of selenous acid) was not to enough to approach the reference values.

Resumo Objetivo: Analisar o estado nutricional relativo ao selênio e verificar o efeito da suplementação desse mineral em pacientes pediátricos durante 14 dias de nutrição parenteral (NP). Método: Trata-se de estudo prospectivo de uma série de casos de pacientes acompanhados durante duas semanas de uso de NP. A coleta de dados foi realizada no início (T0), no 7º (T1) e no 14º dia de NP (T2). Após randomização, o grupo suplementado recebeu 2 µg/kg/dia de ácido selenioso. Peso e altura foram aferidos para avaliação do estado nutricional. Exames coletados: selênio plasmático, albumina, pré-albumina, proteína C-reativa (PCR), colesterol total e HDL-colesterol. Resultados: Foram avaliados 14 pacientes com processo inflamatório em curso e com baixo ou muito baixo peso para a idade. Os pacientes (grupo suplementado e não suplementado) tinham baixas concentrações de selênio. A mediana dos valores de selênio plasmático foi de 17,4 µg/L (T0), 23,0 µg/L (T1) e 20,7 µg/L (T2). Aumento e redução de selênio ocorreram tanto nos pacientes com PCR elevada quanto naqueles que apresentaram normalização desse parâmetro. Conclusão: Os níveis de selênio detectados foram muito baixos e a suplementação (2 µg/kg/dia de ácido selenioso) não foi suficiente para normalização dos níveis plasmáticos.

Radioprotective effect of sodium selenite on bone repair in the tibia of ovariectomized rats

This studyevaluated protection by selenium (Se) in the bone repair process in ovariectomized rats after irradiation. For such purpose, 80 ovariectomized female Wistar rats were randomly divided into 4 experimental groups: ovariectomized (Ov), Ov/Se, Ov/irradiated (Irr) and Ov/ Se/Irr. A bone defect was created on the tibia of all animals 40 days after ovariectomy. Two days after surgery, only the Ov/Se and Ov/Se/Irr rats received 0.8 mg Se/kg. Three days after surgery, only the Ov/Irr and Ov/Se/Irr rats received 10 Gy of x-rays on the lower limb region. The animals were euthanized at 7, 14, 21 and 28 days after surgery to assess the repair process, which was evaluated by analysis of trabecular bone number (Masson Trichrome) and birefringence analysis (Picrosirius). It was possible to observe a delay in the bone repair process in the ovariectomized/irradiated group and similarity between the ovariectomized, Ov/Se and Ov/Se/Irr groups. In conclusion, sodium selenite exerted a radioprotective effect in the bone repair of tibia of ovariectomized rats without toxicity.

Esse estudo avaliou a proteção do selênio no processo de reparação óssea em ratas ovariectomizadas após irradiação. Para isso, 80 ratas Wistar foram divididas aleatoriamente em 4 grupos experimentais: ovariectomizado, ovariectomizado/selênio, ovariectomizado/irradiado e ovariectomizado/selênio/irradiado. Foi realizado um defeito ósseo na tíbia de todos os animais 40 dias após ovariectomia. Dois dias após essa cirurgia, os animais dos grupos ovariectomizado/selênio e ovariectomizado/selênio/irradiado receberam 0,8 mg Se/kg. Três dias após a cirurgia, os animais dos grupos ovariectomizado/irradiado e ovariectomizado/selênio/irradiado receberam 10 Gy de radiação X na região de membros inferiores. Os animais foram sacrificados 7, 14, 21 e 28 dias após a cirurgia para avaliação do processo de reparo ósseo, que foi realizado pela análise do número de trabéculas ósseas (coloração Tricrômico de Masson) e pela análise de birrefringência (coloração de Picrosirius). Foi observado atraso no processo de reparo ósseo no grupo ovariectomizado/irradiado e semelhança entre os grupos ovariectomizado, ovariectomizado/selênio e ovariectomizado/selênio/irradiado. Foi possível concluir que o selenito de sódio exerceu efeito radioprotetor no processo de reparação de tíbias em ratas ovariectomizadas sem toxicidade.

Inhibitory effects of grape seed proanthocyanidin extract on selenite-induced cataract formation and possible mechanism / 华中科技大学学报（医学）（英德文版）

This study investigated the inhibitory effect of grape seed proanthocyanidin extract (GSPE) on selenite-induced cataract formation in rats and the possible mechanism. Eighty 8-day-old Sprague-Dawley rats were divided randomly into 5 groups: control group, model group, three GSPE groups (low dose, medium dose and high dose). Control group received subcutaneous injection of physiological saline. Model group was given subcutaneous injection of sodium selenite (20 μmol/kg body weight) on the postpartum day 10, and once every other day for consecutive three times thereafter. GSPE treated groups were respectively administered GSPE at doses of 50, 100, and 200 mg/kg body weight intragastrically 2 days prior to the selenite injection (that was, on the postpartum day 8), and once daily for fourteen consecutive days thereafter. The opacity of lenses was observed, graded and photographed under the slit lamp microscopy and the maximal diameter of the nuclear cataract plaques was measured. The lenses were analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), malondialdehyde (MDA), calcium (Ca(2+)), nitric oxide (NO) and anti-hydroxyl radical ability (anti-OH(-)). The histomorphology of lenses was observed with HE staining under a light microscope. The levels of calpainII, and iNOS protein and mRNA expression in lenses were detected by using immunohistochemistry and real-time quantitative RT-PCR. The results showed subcutaneous injection of sodium selenite led to severe nuclear cataract in model group, and the achievement ratio of model group was 100%. As compared with model group, the degree of lenses opacity and the maximal diameter of nuclear cataract plaques were significantly reduced in GSPE-treated groups. Moreover, we observed selenite treatment caused a significant decrease in the activities of antioxidative enzymes (SOD, CAT, GSH-PX) and anti-OH(-) ability, accompanied by a significant increase in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. Administration of GSPE could dose-dependently preserve the activities of these antioxidative enzymes and anti-OH(-) ability, accompanied by a significant reduction in the levels of MDA, NO, Ca(2+) as well as iNOS, and calpainII protein and mRNA expression. These results suggested that GSPE markedly prevented selenite-induced cataract formation probably by suppressing the generation of lipid peroxidation and free radicals as well as the activation of iNOS, and calpainII in the lenses.

Alteration of Ionic Zinc Distribution in Rat Spinal Ganglion by Inflammatory Pain Stimulus: Autometallography / 대한해부학회지

This study was designed to investigate any correlation between the mechanism of pain development and changes of histochemically reactive zinc contents in the rat spinal ganglion following complete Freund's Adjuvant (CFA) injection, as an inflammatory pain model. Male Sprague-Dawley rats (270~290 g) were used for this study. Surgeries were done under anesthesia using pentobarbital (30 mg/kg). we injected 200 microliter of CFA subcutaneously in the dorsal aspect of one hind paw using a 30- gauge needle and an 1 mL syringe. Semmes-Weinstein monofilaments was used to test for mechanical hyperalgesia. Finally, zinc selenite autometallography (AMG) was done by Danscher's method. The rat suffered from severe painful swelling of the hindpaw 1 day after a CFA inoculation. Changes in pain threshold were significantly changed on 1 day, and lasted during experiment period of 3 weeks after the CFA inoculation. In control group, ganglion cells vary in size from 15 to 100 micrometer. The smaller neurons are strongly stained with AMG, whereas the larger cells are not almostly stained. Each large ganglion cell is surrounded by perineuronal satellite cells, showing apparent AMG stainity. In experiment group, AMG-positive small ganglion cells increased on 1 day after CFA inoculation, and showed a peak in cell number at 3days group, and decreased gradually after 7 days. We found a small number of large-sized ganglion cells with AMG stainity 7 days and 3 weeks after CFA inoculation. Our results indicate that zinc may be involved in pain mechanism in the spinal ganglion level.

The Serogroup and Antimicrobial Resistance of Salmonella spp. Isolated from the Clinical Specimens During 6 years in a Tertiary University Hospital / 대한임상미생물학회지

BACKGROUND: Recently, non-typhoidal salmonellosis is increasing and it constituted over 90% of total salmonellosis in 1990s. The antimicrobial resistance of non-typhoidal Salmonella gets higher. So we described the change of serogroup and antimicrobial resistance of Salmonella isolated from clinical specimens in Ewha Womans University Mokdong Hospital during 6 years. METHODS: Clinical specimens were submitted from 1997 to 2002. Stool cultures were inoculated onto MacConkey (MAC) agar and Salmonella-Shigella (SS) agar and into Selenite F (SF) enrichment broth. Identification of Salmonella were performed by Vitek GNI card (BioMerieux, Marcy-I'Eltoile, France) and serotyping were done. Antimicrobial resistance test were performed by Vitek GNS card (BioMerieux, Marcy-I'Eltoile, France). RESULTS: From 1997 to 2002, 594 strains of Salmonella were isolated. Non-typhoidal Salmonella and Salmonella typhi constituted 94.4% and 5.6%. Non-typhoidal Salmonella were mainly composed of group B (21.5%) and group D (48.0%), but in 2002, group C (12.4%) and group E (27.9%) were increased in number. The antimicrobial resistance rate of non-typhpoidal Salmonella were 28% to ampicillin, 4.1% to SXT, 0.2% to ciprofloxacin and 0.7% to ceftriaxone. The animicrobial resistance rate of group B and D Salmonella showed 37.5% and 32.6% to ampicillin, 7.8% and 4.2% to SXT, respectively. CONCLUSIONS: Serogroup B and D Salmonella were most frequently isolated, but group C and E Salmonella have been increased in 2002. Antimicrobial resistance of group B and D Salmonella were higher than other serogroups and have been increased year by year.

Usefulness of selenite F enrichment broth for the isolation of Salmonella from stool / 대한임상병리학회지

BACKGROUND: Stool culture for enteric pathogens constitutes a significant portion of the workload in clinical microbiology. Several reports recommended that selenite enrichment have been used only in stool cultures from suspected carriers, during outbreaks, and other special circumstances for cost-effectiveness. We evaluated the usefulness of selenite F enrichment for the isolation of Salmonella in routine stool cultures. METHODS: Stool specimens submitted from March to October, 1999 were inoculated onto MacConkey(Mac) agar and Salmonella-Shiegella(SS) agar and into Selenite F(SF) enrichment broth. After overnight incubation, the SF broth was subcultured onto a second SS agar. RESULTS: Total 45 strains of Salmonella spp. were recovered from 1,338 stool specimens and Shiegella or other enteric pathogens were not recovered. Twenty out of the forty-five Salmonella spp.(44%) were recovered on Mac agar and 33 of 45 Salmonella spp.(73%) on SS agar, 45 out of 45 Salmonella spp.(100%) after SF enrichment and 35 of 45 Salmonella spp.(78%) on Mac and/or SS agar. Ten Salmonella spp. were recovered only after SF enrichment, but no Salmonella spp. were recovered only on the primary Mac agar or SS agar. After SF enrichment, Salmonella spp. grew more purely and heavily than on the primary medium. CONCLUSIONS: These results suggest that SF enrichment is necessary to routine stool cultures and the elimination of the primary Mac or SS agar is cost-effective than the elimination of SF enrichment.

Growth Factors Influencing the Morphology and Growth Rate of Hair Follicles in a Human Hair Organ Culture / 대한피부과학회지

BACKGROUND: In order to study hair biology, a hair organ culture system is necessary. However satisfactory hair culture systems have not been established. OBJECTIVE: The purpose of this study was to examine the effectiveness of growth factors and to establish a hair organ culture system for studying hair biology and to evaluate the effectiveness of growth factors. METHOD: After the healthy human anagen hair follicles were collected without any visible damage, they were cultured in William E medium with several combinations of growth factors including insulin, hydrocortisone, sodium selenite, human transfemn, fetal calf serum and epidermal growth factor at 37C in an atmosphere of 5% CO2/air incubation. The culture medium was changed every 3 days. The results were evaluated by measuring hair growth and hair follicle morphology. RESULTS: The results of this study are summarized as follows; 1) In the medium composed of insulin, hydrocortisone,sodium selenite and human transferrin, the human hair follicles continued to grow at an in vivo rate of 0.3mm in a day over 10 days without change of gross and microscopic morphology. 2) In the medium containing insulin and/or hydrocortisone the growing rate of the human hair follicles was similar to that in vivo, but the follicles revealed premature entry into catagen at 2-6 days in the culture macroscopically and microscopically. 3) Adding fetal calf serum to the above medium made the hair follicles retain the freshly isolated hair follicles morphology for 10 days in culture, even though they grew somewhat slower than the in vivo rate from 6 days in culture. 4) The effectiveness of EGF mimics the in vivo depilation of EGF in sheep. CONCLUSION: To supplement insulin, hydrocortisone, sodium selenite, transferrin as growth factors, William E medium was necessary for maintenance of an in vivo growth rate and the morphology the anagen hair follicles. This culture system is not enough, but it might be useful for investigation of the physiology, biology of hair follicles as well as pharmacology and toxicology in hair.

Selenium Effect on the Frequency of SCEs Induced by Heavy Metals in Human Lymphocytes / 예방의학회지

The protective effect of sodium selenite (Na2SeO3) against the cytogenetic toxicity of heavy metals was investigated on human whole-blood cultures in relation to induction of sister chromatid exchange(SCE) in secondary metaphase chromosome. Methlmercury chloride (CH3HgCl), cadmium chloride (CdCl2), Potassium dichromate (K2Cr2O7), and sodium selenite caused to the typically dose-dependent increase in sister chromatid exchanges (SCEs) by the concentrations ranging from 0.3 micro M to 10 micro M. However, the inductions of sister chromatid exchanges by methymercury chloride or cadmium chloride were inhibited by the simultaneous addition of sodium selenite 1.2 micro M. The frequencies of SCE were decreased to the level of control in the molar ratios as 2 : 1, 1 : 1, 1 : 2, and 1 : 4 of selenium selenite vs. methylmercury chloride, and as 1 : 1 and 1 : 2 of selenium selenite vs. cadmium chloride, while the frequencies of SCE induced by potassium dichromate were not changed by the addition of sodium selenite in culture condition. Mitotic indices were decreased in the higher concentrations of chemicals and not significantly changed by the simultaneous addition of sodium selenite to the culture condition containing each chemicals.