Role of phytohormones in organogenic ability of elm multiplicated shoots

The study presents the comparative analyses of endogenous contents of auxin (IAA), cytokinins (CKs), polyamines (PAs), and phenolic acids (PhAs) in apical and basal parts of elm multiplicated shoots with regard to the organogenic potential. The shoot-forming capacity was higher in the apical part than in the basal part. However, the timing of root formation was in the apical type of explant significantly delayed (compared with the organogenic potential of basal part). Significantly higher contents of free bases, ribosides and ribotides of isopentenyl adenine, zeatin and dihydrozeatin that were found in the apical segments, might be considered as the most important factor affecting in vitro shoot formation. The content of endogenous free IAA was approximately three times higher in the basal shoot parts than in the apical parts. The amounts of putrescine and spermidine were higher in the apical part which generally contains less differentiated tissues than the basal part of shoot. The predominant PhA in both types of explants was caffeic acid, and concentrations of other PhAs decreased in the following order: p-coumaric, ferulic, sinapic, vanillic, chlorogenic, p-hydroxybenzoic and gallic acids. The contents of all determined PhAs in their free forms and higher contents of glycoside-bound p-coumaric, ferulic and sinapic acids, precursors for lignin biosynthesis, were found in the basal parts.     

Production of gold nanoparticles by electrode-respiring Geobacter sulfurreducens biofilms

The goal of this work was to synthesize gold nanoparticles (AuNPs) using electrode-respiring Geobacter sulfurreducens biofilms. We found that AuNPs are generated in the extracellular matrix of Geobacter biofilms and have an average particle size of 20 nm. The formation of AuNPs was verified using TEM, FTIR and EDX. We also found that the extracellular substances extracted from electrode-respiring G. sulfurreducens biofilms reduce Au³⁺ to AuNPs. From FTIR spectra, it appears that reduced sugars were involved in the bioreduction and synthesis of AuNPs and that amine groups acted as the major biomolecules involved in binding.     

Mg2+ distribution in activated sludge and its effects on the nitrifying activity and the characteristics of extracellular polymeric substances and sludge flocs

Divalent cations act as bridges among extracellular polymeric substances (EPS) and form cross-linkage for the self-immobilization of microbial biomass. However, their effects on the nitrification performance during the biological nitrogen removal are still unclear. In the present study, the effects of Mg²⁺ on the nitrifying activity, EPS and floc characteristics were investigated using a lab-scale sequencing batch reactor. The distribution of Mg²⁺ was quantified at different level of sludge floc. The results indicated that the nitrification activity was significantly improved when influent Mg²⁺ was below 1.1 mmol/L, but suppressed at 3 mmol/L. The overall performance characterized by COD, NH₄⁺-N and TN, the particle size and sludge flocculation ability rapidly increased with the increase of Mg²⁺ concentration. Mg²⁺ was mainly distributed in the pellet and changed slightly in supernatant, LB-EPS and TB-EPS. The four fluorescence peaks detected by three-dimensional excitation-emission matrix spectra were attributed to PN-like substances and humic acid-like substances in the LB-EPS and TB-EPS. The results of XPS analysis demonstrated that LB-EPS and TB-EPS comprised similar elements. Therefore, the types of EPS functional groups was unchanged under varied Mg²⁺ concentrations, while their proportions changed and LB-EPS/EPS was key factor for the changes of bioflocculation.     

Characterization of Simultaneous Aerobic Denitrification and Dephosphorization Strain Cupriavidus sp. H29 and Its Application on Cadmium-Removing

Abstract

A cadmium tolerant strain Cupriavidus sp. H29 could be applied on simultaneous removal of nitrate, phosphorus and cadmium. Response surface methodology (RSM) experiments showed that optimal removal ratios of nitrate, phosphate and Cd(II), which reached 98.89%, 75.23% and 85.01%, occurred at Cd(II) initial concentration of 30.00?mg/L, nitrate initial concentration of 55.20?mg/L, phosphate initial concentration of 50.00?mg/L, initial pH of 7.0 and C/N ratio of 6.0. Studies on gaseous product, precipitations and extracellular polymeric substances (EPS) indicated that the removal of Cd(II) occurred in the extracellular place. Through the coordinated complexation of EPS, strain H29 can achieve the bio-induced phosphate-cadmium removal. Moreover, studies on heated cells, resting cells, permeable cells, cells membrane and cytoplasm demonstrated that the removal of Cd(II) mainly taken place on the cells membrane. This study provided the theoretical basis for the subsequent research of synchronous removal of heavy metals and other pollutants.     

Enhancing rice callus regeneration by extracellular products of Tolypothrix tenuis (Cyanobacteria)

Cyanobacteria produce a wide array of substances with activity in many biological systems. The aim of the present research was to compare the effect of differently treated extracellular products (EP) from Tolypothrix tenuis (Cyanobacteria) on rice plantlet regeneration as well as on the pigments, protein, total free porphyrin contents, and 5-aminolevulinate dehydratase (ALA-D) activity in rice callus during differentiation. Rice embryo calli were regenerated in Murashige & Skoog medium supplemented with EP with protein (EPp) or without protein (EPnp) or autoclaved (EPa), as well as with benzyladenine (BA) and benzyladenine + naphthaleneacetic acid (BA + NAA). At day 75, calli percentage regeneration were: EPnp (84%), EPp (58%), BA + NAA (45%), BA (44%), EPa (40%). The same trend was found for chlorophyll a, b, total and carotenoid contents. Protein content in BA, BA + NAA and EPnp treatments was 35% higher than in EPp and EPa. Total free porphyrin was similar in all treatments. ALA-D activity in BA, EPp and EPa treatments was 28% higher than in BA + NAA and EPnp. The extracellular bioactive substance(s) from T. tenuis would contain a mixture of thermolabile plant growth regulators that replaced and improved the effects of synthetic plant growth regulators on rice callus organogenesis. Calli were rhizogenic in all the regeneration media tested. The pigment content of the calli was related to percentage regeneration but not to the total free porphyrin and ALA-D activity.     

Lignite Biosolubilization by Bacillus sp. RKB 2 and Characterization of its Products

Abstract

Nowadays, the advancements of coal microbiology and biotechnology have been highly emphasized, providing leading-edge approaches in sustainable development of agriculture and the protection of the environment. The biosolubilization of low-rank coals, such as lignite and leonardite is a promising technology for converting these sedimentary rocks into valuable products. In this study, the process involved in lignite biosolubilization by Bacillus sp. RKB 2 was investigated. The biotransformed lignite and the produced humic substances were determined in vitro in a liquid medium and on a solid matrix. The bacterial strain was isolated from untreated Kazakhstani lignite and was shown to be capable of effectively solubilizing and transforming lignite (5% w/v). Fourier Transform Infrared (FTIR) and UHPLC-QqQ-MS/MS analyses were performed to examine the solubilization products and lignite humic substances processed by bacteria. The absorption peaks of FTIR showed the diverse nature of the bacteria-induced humic substances, and the vast majority of intense peaks detected are mainly below an m/z of 1000?Da (liquid chromatography-mass spectrometry [LC-MS] (QqQ)). Data analysis concluded that our isolate could depolymerize lignite and form bio-humic substances. Due to its ability to solubilize lignite Bacillus sp. RKB 2 may be useful in the coal-bed for in situ bioutilization of low-rank coal.     

Assessment of heavy metal toxicity related with human health risk in the surface water of an industrialized area by a novel technique

This study innovates an assessment technique to evaluate heavy metal toxic load (HMTL). Assessment of surface water in Durgapur industrial area, West Bengal India illustrates that heavy metals in majority of sampling locations exceed the drinking water quality standards. Therefore, pollution status and health impact were predicted by heavy metal pollution index (HPI) and hazard index (HI). More than 50% of sampling locations were marked as polluted. Moreover, 5% and 90% of sampling locations near the industries have health risk to adult and child on ingestion. The study of specific exposure-time and exposure-duration affirms the suitability of water for fishing and regular activities. However, HPI or HI does not quantify heavy metal concentrations that pose threat to human health. Therefore, the proposed assessment technique, HMTL, determines the concentration of heavy metals responsible for health hazard. HMTL identifies Mn, Pb, and Co as toxic metals and estimates 85%, 63%, and 70% removal of these metals from surface water to limit pollution. Origins of metals were also investigated through statistical techniques, which revealed that Fe has geogenic and anthropogenic source, while other metals originate by anthropogenic activities solely. This study demonstrates that HMTL will help the planning authority to document effective water quality management plan.     

Superoxide dismutase, glutathione peroxidase, and glutathione reductase in sheep organs

The enzyme activities of the superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione reductase (GR) and thiobarbituric acid reactive substances (TBARS) content were measured in tissue extracts of the liver, kidney and lung of sheep in a nonpolluted control area (C), a polluted area pasture (PP) and those from polluted areas but fed in the laboratory with an experimental emission supplement diet (EEF). Compared with the control SOD, activity was significantly increased (1.75 times) only in the liver of the PP group. In the EEF group there was a tendency toward lower activities in all organs. The Cu,Zn-SOD isoenzymes pattern analyzed by isoelectrofocusing was different in the organs of the animals exposed to pollutants when compared with those of the controls. In the liver, two new isoenzymes with pI 5.30 and 5.70 were found in the PP group and an additional isoenzyme with pI 5.10 in the EEF group. The kidney isoenzymes with pl 5.30 and 5.40 were inhibited in the EEF group. In the lung, two new isoenzymes appeared with pl 5.30 and 5.40 in the PP group and two new isoenzymes with pI 6.10 and 6.50 in the EEF group. GSHPx activity was inhibited in the liver and kidney of the sheep exposed to pollutants. GR activity was significantly changed only in the liver. The activity in the PP group was 2.30 and 2.10 times higher than in the C and EEF groups, respectively. TBARS content was increased in the liver and kidney of the EEF group compared with the control.