Successful Enrichment Research Articles

Application of anaerobic dynamic membrane bioreactor (AnDMBR) for the successful enrichment of Anammox bacteria using mixed anaerobic and aerobic seed sludge

This study investigated a novel bioreactor configuration coupled with a side-stream dynamic membrane (DM) for Anammox enrichment as an alternative for conventional membrane. Bioreactor was fed with synthetic feed and seeded with a mix of anaerobic and aerobic sludge. In situ mechanical cleaning was employed for DM cleaning. DM development and performance was analysed over two polyamide-nylon meshes (200 and 52 µm). Solid-liquid separation of 52 µm mesh outperformed 200 µm with an average effluent turbidity of 2.4 ± 0.1 NTU. The system was operated at a maximum nitrogen loading rate of 696 mg-N L−1 d−1 and achieved a maximum nitrogen removal rate of 611.6 mg-N L−1 d−1. At steady state, the average ammonium, nitrite and total nitrogen removal efficiencies were 87 ± 0.6%, 98.5 ± 0.15% and 87.5 ± 0.56% respectively. Digital realtime PCRSequence analysis showed that Planctomycetales belonging to ascertained Anammox-specific genera progressively increased their presence in the reactor consistently with its nitrogen removal performance.

The miniaturised solid phase extraction of some trace metals using graphene nanoplatelets by GFAAS

ABSTRACTIn order to separate and enrich of cadmium, copper, lead and nickel before its determination with graphene nanoplatelets by atomic absorption spectrometry was described. For this aim, analyte elements were collected on sorbent in mini filter. The influences of experimental conditions (pH of sample, amount of sorbent, concentration of eluent, foreign ions), retention and elution parameters on the recovery of the analyte elements were examined. After the optimisation of experimental parameters, a successful separation and enrichment were obtained at pH = 7 and eluted with 0.1 M of HNO3 applying a 20 mL/min of drawing and discharging rates for sorption and elution steps with high (>95%) quantitative recovery and high precision (<10% relative standard deviation). Using the proposed technique, the cadmium, copper, lead and nickel in various water samples (tap water and river water) could be practically and easily removed and enriched with 95% confidence level. The limit of detection for cadmium, copper, lead and nickel was 0.78, 0.41, 5.40 and 0.44 μg/L (3σ, N = 10), respectively. The proposed technique was fast, simple, environmental friendly and economic.

Establishing anaerobic hydrocarbon-degrading enrichment cultures of microorganisms under strictly anoxic conditions.

Traditionally, the description of microorganisms starts with their isolation from an environmental sample. Many environmentally relevant anaerobic microorganisms grow very slowly, and often they rely on syntrophic interactions with other microorganisms. This impedes their isolation and characterization by classic microbiological techniques. We developed and applied an approach for the successive enrichment of syntrophic hydrocarbon-degrading microorganisms from environmental samples. We collected samples from microbial mat-covered hydrothermally heated hydrocarbon-rich sediments of the Guaymas Basin and mixed them with synthetic mineral medium to obtain sediment slurries. Supplementation with defined substrates (i.e., methane or butane), incubation at specific temperatures, and a regular maintenance procedure that included the measurement of metabolic products and stepwise dilutions enabled us to establish highly active, virtually sediment-free enrichment cultures of actively hydrocarbon-degrading communities in a 6-months to several-years' effort. Using methane as sole electron donor shifted the originally highly diverse microbial communities toward defined mixed cultures dominated by syntrophic consortia consisting of anaerobic methane-oxidizing archaea (ANME) and different sulfate-reducing bacteria. Cultivation with butane at 50 °C yielded consortia of archaea belonging to Candidatus Syntrophoarchaeum and Candidatus Desulfofervidus auxilii partner bacteria. This protocol also describes sampling for further molecular characterization of enrichment cultures by fluorescence in situ hybridization (FISH), and transcriptomics and metabolite analyses, which can provide insights into the functioning of hydrocarbon metabolism in archaea and resolve important mechanisms that enable electron transfer to their sulfate-reducing partner bacteria.

Enrichment and characterization of autotrophic Thiobacillus denitrifiers from anaerobic sludge for nitrate removal

Abstract An efficient and cost-effective method was established to enrich sulfur-based autotrophic denitrifiers from anaerobic sludge from a municipal wastewater treatment plant. Successful enrichment was achieved using thiosulfate as a substrate after 28 days at 30 °C under anaerobic conditions. Terminal restriction fragment length polymorphism (TRFLP) and high-throughput Illumina sequencing of 16S rRNA genes were applied to investigate the evolution of the microbial community during the enrichment, and observed a significant reduction in the bacterial diversity along the enrichment. Illumina sequencing showed that Thiobacillus became the dominant genus in the final enrichment culture, in which autotrophic denitrification rate was 21 mg N2-N (g VS d)−1. In addition, flow-through nanostructured pyrrhotite (NPyr) packed biofilters seeded with the final enrichment culture were evaluated for the autosulfurotrophic denitrification of nitrate-contaminated water. Stable and complete nitrate reduction of 30.24 mg NO3−-N kgNPyr−1 d−1 was achieved under a loading rate of 56 mg NO3−-N (L d)−1 in a 30-day trial. Further research is needed to determine the potential of NPyr-packed biofilters to remove nitrogen, and to verify the efficacy of this technology for simultaneous nitrogen and phosphorus removal in general engineering practice.

Metagenomic Analysis of a Biphenyl-Degrading Soil Bacterial Consortium Reveals the Metabolic Roles of Specific Populations.

Polychlorinated biphenyls (PCBs) are widespread persistent pollutants that cause several adverse health effects. Aerobic bioremediation of PCBs involves the activity of either one bacterial species or a microbial consortium. Using multiple species will enhance the range of PCB congeners co-metabolized since different PCB-degrading microorganisms exhibit different substrate specificity. We have isolated a bacterial consortium by successive enrichment culture using biphenyl (analog of PCBs) as the sole carbon and energy source. This consortium is able to grow on biphenyl, benzoate, and protocatechuate. Whole-community DNA extracted from the consortium was used to analyze biodiversity by Illumina sequencing of a 16S rRNA gene amplicon library and to determine the metagenome by whole-genome shotgun Illumina sequencing. Biodiversity analysis shows that the consortium consists of 24 operational taxonomic units (≥97% identity). The consortium is dominated by strains belonging to the genus Pseudomonas, but also contains betaproteobacteria and Rhodococcus strains. whole-genome shotgun (WGS) analysis resulted in contigs containing 78.3 Mbp of sequenced DNA, representing around 65% of the expected DNA in the consortium. Bioinformatic analysis of this metagenome has identified the genes encoding the enzymes implicated in three pathways for the conversion of biphenyl to benzoate and five pathways from benzoate to tricarboxylic acid (TCA) cycle intermediates, allowing us to model the whole biodegradation network. By genus assignment of coding sequences, we have also been able to determine that the three biphenyl to benzoate pathways are carried out by Rhodococcus strains. In turn, strains belonging to Pseudomonas and Bordetella are the main responsible of three of the benzoate to TCA pathways while the benzoate conversion into TCA cycle intermediates via benzoyl-CoA and the catechol meta-cleavage pathways are carried out by beta proteobacteria belonging to genera such as Achromobacter and Variovorax. We have isolated a Rhodococcus strain WAY2 from the consortium which contains the genes encoding the three biphenyl to benzoate pathways indicating that this strain is responsible for all the biphenyl to benzoate transformations. The presented results show that metagenomic analysis of consortia allows the identification of bacteria active in biodegradation processes and the assignment of specific reactions and pathways to specific bacterial groups.

Amine-Reactive Poly(pentafluorophenyl acrylate) Brush Platforms for Cleaner Protein Purification.

Reactive pentafluorophenyl acrylate (PFPA) polymer brushes grafted on silica particles were prepared using surface-initiated reversible addition and fragmentation chain transfer polymerization. The polymer brush was successfully immobilized with antibody, then used for protein separation. The immunoprecipitated proteins showed successful enrichment of target protein, with reduced nonspecific background and less contamination from eluted antibodies. To further improve protein recovery, the hydrophobic poly(PFPA) brush was modified with hydrophilic poly(ethylene glycol) (PEG). The partially PEG-substituted poly(PFPA) brush showed better dispersion in aqueous solution, leading to improved antibody immobilization efficiency. By optimizing both the brush molecular weight and the degree of PEG substitution, an optimal balance between surface hydrophilicity and number of available PFP units was found, leading to efficient target protein purification. This study shows that poly(PFPA) platform offers a versatile approach to prepare biomolecule-activated surfaces with tunable surface property, which has potential applications in protein separation and other areas.

Evaluation of a dustbathing substrate and straw bales as environmental enrichments in commercial broiler housing

The use of straw bales as an environmental enrichment is common for broiler chickens in enriched housing systems, however relatively little information exists about their effectiveness in improving welfare. There has also been no widespread introduction of a dustbathing material for broilers. The main aim of this trial was to evaluate the use of a dustbathing substrate (in the form of oat hulls), both as an alternative to straw bales and as a supplementary enrichment. Over four replicates, four commercial houses, each containing approximately 22,000 broilers, were assigned to one of four treatments over the 6-week production cycle: (1) straw bales (B; one per 155m2), (2) oat hulls as a dustbathing substrate (OH; provided in 1m diameter steel rings, one per 155m2), (3) both oat hulls and straw bales (OH+B), and (4) a control treatment with no environmental enrichment (C). Observations of broiler behaviour and leg health were taken weekly, and performance data was collected for each cycle. Broilers housed in the OH and OH+B treatments had better gait scores in week 6 than those housed in the C treatment (P<0.05), which suggests that the provision of oat hulls improved bird leg health. However, there was no associated increase in activity levels in unenriched areas of the houses. Conversely, more locomotion (P<0.001), less sitting inactive (P<0.001) and less sitting pecking (P<0.001) were observed in the C treatment than in unenriched areas of B, OH and OH+B treatments. More birds were recorded around the bales compared to the oat hulls (P<0.001), however birds performed significantly more foraging (P=0.019) and dustbathing (P=0.045) in oat hulls than around straw bales. Although oat hulls appear to be more suitable for stimulating active behaviours than straw bales, the high level of resting recorded around the bales suggests they may have a positive function as protective cover. The presence of an additional type of enrichment in the house did not affect the number of birds, or the type of behaviours performed in close proximity to either straw bales or oat hulls (P>0.05). Treatment did not have a significant effect on pododermatitis levels or slaughter weight, on mortality rates, or on litter quality or atmospheric ammonia levels (P>0.05). Overall, our results suggest that the oat hulls substrate was a successful enrichment in terms of promoting dustbathing and foraging, and improving bird leg health. The straw bales also appeared attractive to the birds, however, which suggests that a dustbathing substrate should be a supplementary enrichment.

The effect of dietary supplementation with Aurantiochytrium limacinum on lactating dairy cows in terms of animal health, productivity and milk composition.

The aim of this study was to investigate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA), on a variety of health and productivity parameters in lactating cows. Twenty-four cows were blocked by parity and number of days in milk and then randomly assigned to a control (CON; n=12) group with no algal supplementation, or a treatment group (AURA; n=12) provided with 100g AURAcow-1 day-1 or 16g DHAcow-1 day-1 . A variety of health and productivity measurements were taken, and results indicated that supplementation had no negative effects on animal health in terms of somatic cell count, haematological and biochemical blood parameters, while body condition was marginally improved by algal supplementation. No differences were found for the various production parameters measured; however, a tendency towards increased milk production was observed for the AURA group during the final stage of the study (+4.5kgcow-1 day-1 , day 78-84). The fatty acid profile of milk was improved by supplementation, with significantly lower saturated fatty acids, significantly higher omega-3 fatty acids and an improved omega-3/omega-6 ratio observed when compared to the control group. The amount of DHA in the milk of cows provided 105g AURAhead-1 day-1 was 4.7mg/100g milk with a peak transfer efficiency from feed to milk at day 49 of 8.3%. These results indicate that supplementation with 105g AURAhead-1 day-1 resulted in the successful enrichment of milk with DHA without negatively impacting the health or productivity of the animals.

Global Transcriptome Profiling of Xanthomonas oryzae pv. oryzae under in planta Growth and in vitro Culture Conditions.

Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial blight, is a major threat to rice productivity. Here, we performed RNA-Seq based transcriptomic analysis of Xoo transcripts isolated under in planta growth (on both susceptible and resistant hosts) and in vitro culture conditions. Our in planta extraction method resulted in successful enrichment of Xoo cells and provided RNA samples of high quality. A total of 4,619 differentially expressed genes were identified between in planta and in vitro growth conditions. The majority of the differentially expressed genes identified under in planta growth conditions were related to the nutrient transport, protease activity, stress tolerance, and pathogenicity. Among them, over 1,300 differentially expressed genes were determined to be secretory, including 184 putative type III effectors that may be involved in Xoo pathogenicity. Expression pattern of some of these identified genes were further validated by semi-quantitative RT-PCR. Taken together, these results provide a transcriptome overview of Xoo under in planta and in vitro growth conditions with a focus on its pathogenic processes, deepening our understanding of the behavior and pathogenicity of Xoo.

Electrokinetically driven continuous-flow enrichment of colloidal particles by Joule heating induced temperature gradient focusing in a convergent-divergent microfluidic structure

Enrichment of colloidal particles in continuous flow has not only numerous applications but also poses a great challenge in controlling physical forces that are required for achieving particle enrichment. Here, we for the first time experimentally demonstrate the electrokinetically-driven continuous-flow enrichment of colloidal particles with Joule heating induced temperature gradient focusing (TGF) in a microfluidic convergent-divergent structure. We consider four mechanisms of particle transport, i.e., advection due to electroosmosis, electrophoresis, dielectrophoresis and, and further clarify their roles in the particle enrichment. It is experimentally determined and numerically verified that the particle thermophoresis plays dominant roles in enrichment of all particle sizes considered in this study and the combined effect of electroosmosis-induced advection and electrophoresis is mainly to transport particles to the zone of enrichment. Specifically, the enrichment of particles is achieved with combined DC and AC voltages rather than a sole DC or AC voltage. A numerical model is formulated with consideration of the abovementioned four mechanisms, and the model can rationalize the experimental observations. Particularly, our analysis of numerical and experimental results indicates that thermophoresis which is usually an overlooked mechanism of material transport is crucial for the successful electrokinetic enrichment of particles with Joule heating induced TGF.

Drug repurposing for aging research using model organisms.

SummaryMany increasingly prevalent diseases share a common risk factor: age. However, little is known about pharmaceutical interventions against aging, despite many genes and pathways shown to be important in the aging process and numerous studies demonstrating that genetic interventions can lead to a healthier aging phenotype. An important challenge is to assess the potential to repurpose existing drugs for initial testing on model organisms, where such experiments are possible. To this end, we present a new approach to rank drug‐like compounds with known mammalian targets according to their likelihood to modulate aging in the invertebrates Caenorhabditis elegans and Drosophila. Our approach combines information on genetic effects on aging, orthology relationships and sequence conservation, 3D protein structures, drug binding and bioavailability. Overall, we rank 743 different drug‐like compounds for their likelihood to modulate aging. We provide various lines of evidence for the successful enrichment of our ranking for compounds modulating aging, despite sparse public data suitable for validation. The top ranked compounds are thus prime candidates for in vivo testing of their effects on lifespan in C. elegans or Drosophila. As such, these compounds are promising as research tools and ultimately a step towards identifying drugs for a healthier human aging.

Environmental Enrichment for Broiler Breeders: An Undeveloped Field.

Welfare problems, such as hunger, frustration, aggression, and abnormal sexual behavior, are commonly found in broiler breeder production. To prevent or reduce these welfare problems, it has been suggested to provide stimulating enriched environments. We review the effect of the different types of environmental enrichment for broiler breeders, which have been described in the scientific literature, on behavior and welfare. Environmental enrichment is defined as an improvement of the environment of captive animals, which increases the behavioral opportunities of the animal and leads to improvements in biological function. This definition has been broadened to include practical and economic aspects as any enrichment strategy that adversely affects the health of animals (e.g., environmental hygiene), or that has too many economic or practical constraints will never be implemented on commercial farms and thus never benefit animals. Environmental enrichment for broiler breeders often has the purpose of satisfying the behavioral motivations for feeding and foraging, resting, and/or encouraging normal sexual behavior. Potentially successful enrichments for broiler breeders are elevated resting places, cover panels, and substrate (for broiler breeders housed in cage systems). However, most of the ideas for environmental enrichment for broiler breeders need to be further developed and studied with respect to the use, the effect on behavior and welfare, and the interaction with genotype and production system. In addition, information on practical use and the economics of the production system is often lacking although it is important for application in practice.

Enrichment and Nitrogen Removal Characteristics of Marine Anaerobic Ammonium Oxidizing Bacteria

In this work, enrichment and nitrogen removal characteristics of marine anaerobic ammonium oxidizing bacteria were investigated by seeding sediment sludge from the Jiaozhou bay. Experimental results showed that the whole process could be divided into four phases:bacterial lysis phase (1-15 d), lag phase (16-152 d), exponential growth phase (153-183 d) and stationary phase (184-192 d). Compared to freshwater anaerobic ammonium oxidizing bacteria, the lag phase (137 d) was longer. However, the exponential growth phase (30 d) was shorter. Besides, marine anaerobic ammonium oxidizing bacteria were more sensitive to variation in substrate concentration and HRT. The activity delay time caused by inflow and effluent was 5 h, which was far longer than fresh anaerobic ammonium oxidizing bacteria. As a result, the adaptive ability of marine anaerobic ammonium oxidizing bacteria was weaker and it was harder to enrich. After successful enrichment of 192 d, the removal rates of ammonia nitrogen and nitrite nitrogen were 96.98% and 95.66%, respectively. n(NH4+-N):n(NO2--N):n(NO3--N) was 1:(1.2±0.2):(0.22±0.06), which was close to the theoretical ratio. NRRNH4+-Nwas 0.080 kg·(m3·d)-1, which indicated that the activity of marine anaerobic ammonium oxidizing bacteria increased significantly. The enrichment of marine anaerobic ammonium oxidizing bacteria was achieved. The sludge characteristics changed from black to red. SEM observation confirmed that the red granule was cenobium, which consisted of closely spaced micrococcus with smooth surface and crateriform shape.

Environmental Enrichment Mitigates Deficits after Repetitive Mild Traumatic Brain Injury.

Although environmental enrichment has been shown to improve functional and histologic outcomes in pre-clinical moderate-to-severe traumatic brain injury (TBI), there are a paucity of pre-clinical data regarding enrichment strategies in the setting of repetitive mild traumatic brain injury (rmTBI). Given the vast numbers of athletes and those in the military who sustain rmTBI, the mounting evidence of the long-term and progressive sequelae of rmTBI, and the lack of targeted therapies to mitigate these sequelae, successful enrichment interventions in rmTBI could have large public health significance. Here, we evaluated enrichment strategies in an established pre-clinical rmTBI model. Seventy-one male C57BL/6 mice were randomized to two different housing conditions, environmental enrichment (EE) or normal condition (NC), then subjected to rmTBI injury (seven injuries in 9 days) or sham injury (anesthesia only). Functional outcomes in all four groups (NC-TBI, EE-TBI, NC-sham, and EE-sham) were assessed by motor, exploratory/anxiety, and mnemonic behavioral tests. At the synaptic level, N-methyl d-aspartate receptor (NMDAR) subunit expression of phosphorylated glutamate receptor 1 (GluR1), phosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII), and calpain were evaluated by western blot. Compared to injured NC-TBI mice, EE-TBI mice had improved memory and decreased anxiety and exploratory activity post-injury. Treatment with enrichment also corresponded to normal NMDAR subunit expression, decreased GluR1 phosphorylation, decreased phosphorylated CaMKII, and normal calpain expression post-rmTBI. These data suggest that enrichment strategies may improve functional outcomes and mitigate synaptic changes post-rmTBI. Given that enrichment strategies are feasible in the clinical setting, particularly for athletes and soldiers for whom the risk of repetitive injury is greatest, these data suggest that clinical trials may be warranted.

Exonuclease-Catalyzed Methylene Blue Releasing and Enriching onto a Dodecanethiol Monolayer for an Immobilization-Free and Highly Sensitive Electrochemical Nucleic Acid Biosensor.

Herein, a unique and versatile immobilization-free electrochemical nucleic acid biosensor architecture is proposed for the first time based on the catalyzed release of a methylene blue (MB)-tagged mononucleotide by exonuclease III (Exo III) and the successive enrichment onto a dodecanethiol monolayer, which can be attributed to the hydrophobic force between the alkyl chain of the dodecanethiol monolayer and the hydrophobic part of the MB-tagged mononucleotide. The fabricated biosensor demonstrates considerable advantages including assay simplicity, rapidness, and high sensitivity owing to its immobilization-free and homogenous operation for the biorecognition and amplification process. A low detection limit of approximately 1 pM toward the target DNA could be achieved with an excellent selectivity. The proposed immobilization-free electrochemical biosensing strategy was also extended for the assay of Exo I and III activity. Furthermore, it might be easily extended for the detection of a wide spectrum of targets and thus provide a promising avenue for the development of immobilization-free and sensitive electrochemical biosensors.

Improving full-field identification using progressive model enrichments

Full-field identification methods such as finite element model updating or integrated digital image correlation minimize the gap between an experiment and a simulation by iterative schemes. Within the algorithms residual fields and sensitivity fields are used to achieve identification. This paper discusses how these same fields can be used to assess the quality of the identification and guide toward successive enrichment of the constitutive model to progressively reduce the experiment-model gap. A cyclic experiment on a dog-bone sample made of aluminum alloy is used as an example to identify the parameters of an elastoplastic model with exponential hardening and anisotropic yielding.

DNA-Templated Aptamer Probe for Identification of Target Proteins.

Using aptamers as molecular probes for biomarker discovery has attracted a great deal of attention in recent years. However, it is still a big challenge to accurately identify those protein markers that are targeted by aptamers under physiological conditions due to weak and noncovalent aptamer-protein interactions. Herein, we developed an aptamer based dual-probe using DNA-templated chemistry and photo-cross-linking technique for the identification of target proteins that are recognized by aptamers. In this system, the aptamer was modified by a single strand DNA as binding probe (BP), and another complementary DNA with a photoactive group and reporter group was modified as capture probe (CP). BP was first added to recruit the binding protein via aptamer recognition, and subsequently CP was added to let the cross-linker close to the target via DNA self-assembly, and then a covalent bond between CP and its binding protein was achieved via photo-cross-linking reaction. The captured protein can be detected or affinity enrichment using the tag, finally identified by MS. By use of lysozyme as a model substrate, we demonstrated that this multiple functionalized probe can be utilized for a successful labeling and enrichment of target protein even under a complicated and real environment. Thus, a novel method to precisely identify the aptamer-targeted proteins has been developed and it has a potential application for discovery of aptamer-based biomarkers.

Quantitative PCR is a Valuable Tool to Monitor the Performance of DNA-Encoded Chemical Library Selections.

Phage-display libraries and DNA-encoded chemical libraries (DECLs) represent useful tools for the isolation of specific binding molecules from large combinatorial sets of compounds. With both methods, specific binders are recovered at the end of affinity capture procedures by using target proteins of interest immobilized on a solid support. However, although the efficiency of phage-display selections is routinely quantified by counting the phage titer before and after the affinity capture step, no similar quantification procedures have been reported for the characterization of DECL selections. In this article, we describe the potential and limitations of quantitative PCR (qPCR) methods for the evaluation of selection efficiency by using a combinatorial chemical library with more than 35 million compounds. In the experimental conditions chosen for the selections, a quantification of DNA input/recovery over five orders of magnitude could be performed, revealing a successful enrichment of abundant binders, which could be confirmed by DNA sequencing. qPCR provided rapid information about the performance of selections, thus facilitating the optimization of experimental conditions.

Ti(IV) carrying polydopamine-coated, monodisperse-porous SiO2 microspheres with stable magnetic properties for highly selective enrichment of phosphopeptides

A marked decrease in the saturation magnetization by the formation of functional shells around the magnetic core is an important disadvantage of magnetic core-shell nanoparticles. Another drawback of Ti(IV)-functionalized immobilized metal affinity chromatography (IMAC) sorbents is the acidic character of the binding medium used for Ti4+ attachment onto composite magnetic nanoparticles, which causes an additional decrease in the saturation magnetization owing to the chemical interaction between the acidic moiety and the magnetic core. An IMAC sorbent in the form of magnetic microspheres with superior and stable magnetic properties with respect to magnetic core-shell nanoparticles was designed for phosphopeptide enrichment. Magnetic, monodisperse-porous silica microspheres (MagSiO2) 6μm in size were synthesized by a new staged-shape template hydrolysis-condensation protocol. A porous-silica shell layer was generated around the microspheres to protect the magnetic core from the acidic medium during Ti4+ attachment (MagSiO2@SiO2). The MagSiO2@SiO2 microspheres were coated with a polydopamine shell (MagSiO2@SiO2@PDA) and Ti4+ was attached onto the composite microspheres (MagSiO2@SiO2@PDA@Ti(IV)). Formation of the PDA layer and Ti4+ attachment did not cause any significant decrease in the saturation magnetization. The platform exhibited excellent performance for phosphopeptide enrichment from the digests of phosphorylated proteins. Selectivity was investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The detection limit for phosphopeptide enrichment by the MagSiO2@SiO2@PDA@Ti(IV) microspheres from the tryptic digests of β-casein was 50 fmol/mL. Usability of the proposed magnetic sorbent with complex biological samples was demonstrated by successful enrichment of four phosphopeptides from human serum. The proposed sorbent showed stable performance over five repeated uses.

Astrobiological implications of dim light phototrophy in deep-sea red clays

Red clays of Central Indian Basin (CIB) under influence of trace of Rodriguez Triple Junction exhibited chemoautotrophy, low temperature hydrothermal alterations and photoautotrophic potential. Seamount flank TVBC-08, hosting such signatures revealed dominance of aerobic anoxygenic phototroph Erythrobacter, with 93% of total 454 pyrosequencing tags. Subsequently, enrichments for both aerobic (Erythrobacter) and anaerobic anoxygenic phototrophs (green and purple sulphur bacteria) under red and white LED light illumination, with average irradiance 30.66Wm−2, were attempted for three red-clay sediment cores. Successful enrichments were obtained after incubation for c.a. 120 days at 4°± 2 °C and 25°± 2 °C, representing ambient psychrophilic and low temperature hydrothermal alteration conditions respectively. During hydrothermal cooling, a microbial succession from anaerobic chemolithotrophy to oxygenic photoautotrophy through anaerobic/aerobic anoxygenic phototrophic microbes is indicated. Spectral absorbance patterns of the methanol extracted cell pellets showed peaks corresponding to metal sulphide precipitations, the Soret band of chlorosome absorbance by photosystem II and absence of peaks at Qy transition band. Dendritic nano-structures of metal sulphides are common in these sediments and are comparable with other sulphidic paleo-marine Martian analogues. Significant blue and redshifts have been observed for the experimental samples relative to the un-inoculated medium. These observations indicate the propensity of metal-sulphide deposits contributing to chemiluminiscence supporting the growth of phototrophs at least partially, in the otherwise dark abyss. The effects of other geothermal heat and light sources are also under further consideration. The potential of phototrophic microbial cells to exhibit Doppler shift in absorbance patterns is significant towards understanding planetary microbial habitability. Planetary desiccation could considerably influence Doppler effects and consequently spectral detection techniques exo-planetary microbial life.