Common Biomolecules Research Articles

Flexible electrospun test strips functionalized with a graphene oxide/doxorubicin complex for dopamine detection

A novel flexible test strip has been developed for the selective and sensitive detection of dopamine (DA) using an electrospun polyacrylonitrile nanofiber membrane as a substrate and doxorubicin (DOX)-functionalized graphene oxide (GO) as a fluorescent ligand. Employing the Langmuir-Blodgett technique, the fluorescent probe of GO/DOX was controllably and flatly applied onto the surface of nanofiber membranes. The adsorption behavior of DA and DOX on GO in solution and on the surface of solid test strips has been investigated, respectively. The results showed that DA exhibited a higher affinity for GO, both in solution and on the surface of test strips, compared to DOX. Due to the competitive adsorption of DOX and DA onto GO, the addition of DA to the GO/DOX complex led to a significant fluorescence enhancement, attributed to the replacement of the GO-supported DOX with DA of a higher adsorption affinity to GO, enabling the detection of DA. This nanofiber-based method proves to be simple, sensitive, selective, and effectively minimizes interference from common biomolecules and small molecules in serum. Thus, this portable, cost-effective, and selective nanofiber strip holds great promise for early diagnosis of neurodegenerative diseases by measuring DA levels.

Simulating temperature and tautomeric effects for vibrationally resolved XPS of biomolecules: Combining time-dependent and time-independent approaches to fingerprint carbonyl groups.

Carbonyl groups (C=O) play crucial roles in the photophysics and photochemistry of biological systems. O1s x-ray photoelectron spectroscopy allows for targeted investigation of the C=O group, and the coupling between C=O vibration and O1s ionization is reflected in the fine structures. To elucidate its characteristic vibronic features, systematic Franck-Condon simulations were conducted for six common biomolecules, including three purines (xanthine, caffeine, and hypoxanthine) and three pyrimidines (thymine, 5F-uracil, and uracil). The complexity of simulation for these biomolecules lies in accounting for temperature effects and potential tautomeric variations. We combined the time-dependent and time-independent methods to efficiently account for the temperature effects and to provide explicit assignments, respectively. For hypoxanthine, the tautomeric effect was considered by incorporating the Boltzmann population ratios of two tautomers. The simulations demonstrated good agreement with experimental spectra, enabling differentiation of two types of carbonyl oxygens with subtle local structural differences, positioned between two nitrogens (O1) or between one carbon and one nitrogen (O2). The analysis provided insights into the coupling between C=O vibration and O1s ionization, consistently showing an elongation of the C=O bond length (by 0.08-0.09Å) upon O1s ionization.

Dearomatization drives complexity generation in freshwater organic matter

Dissolved organic matter (DOM) is one of the most complex, dynamic and abundant sources of organic carbon, but its chemical reactivity remains uncertain1–3. Greater insights into DOM structural features could facilitate understanding its synthesis, turnover and processing in the global carbon cycle4,5. Here we use complementary multiplicity-edited 13C nuclear magnetic resonance (NMR) spectra to quantify key substructures assembling the carbon skeletons of DOM from four main Amazon rivers and two mid-size Swedish boreal lakes. We find that one type of reaction mechanism, oxidative dearomatization (ODA), widely used in organic synthetic chemistry to create natural product scaffolds6–10, is probably a key driver for generating structural diversity during processing of DOM that are rich in suitable polyphenolic precursor molecules. Our data suggest a high abundance of tetrahedral quaternary carbons bound to one oxygen and three carbon atoms (OCqC3 units). These units are rare in common biomolecules but could be readily produced by ODA of lignin-derived and tannin-derived polyphenols. Tautomerization of (poly)phenols by ODA creates non-planar cyclohexadienones, which are subject to immediate and parallel cycloadditions. This combination leads to a proliferation of structural diversity of DOM compounds from early stages of DOM processing, with an increase in oxygenated aliphatic structures. Overall, we propose that ODA is a key reaction mechanism for complexity acceleration in the processing of DOM molecules, creation of new oxygenated aliphatic molecules and that it could be prevalent in nature.

Nitrodopamine modified MnO2 NS-MoS2QDs hybrid nanocomposite for the extracellular and intracellular detection of glutathione.

We have developed a highly sensitive and reliable fluorescence resonance energy transfer (FRET) probe using nitro-dopamine (ND) and dopamine (DA) coated MnO2 nanosheet (ND@MnO2 NS and DA@MnO2 NS) as an energy acceptor and MoS2 quantum dots (QDs) as an energy donor. By employing surface-modified MnO2 NS, we can effectively reduce the fluorescence intensity of MoS2 QDs through FRET. It can reduce MnO2 NS to Mn2+ and facilitate the fluorescence recovery of the MoS2 QDs. This ND@MnO2 NS@MoS2 QD-based nanoprobe demonstrates excellent sensitivity to GSH, achieving an LOD of 22.7 nM in an aqueous medium while exhibiting minimal cytotoxicity and good biocompatibility. Moreover, our sensing platform shows high selectivity to GSH towards various common biomolecules and electrolytes. Confocal fluorescence imaging revealed that the nanoprobe can image GSH in A549 cells. Interestingly, the ND@MnO2 NS nanoprobe demonstrates no cytotoxicity in living cancer cells, even at concentrations up to 100 μg mL-1. Moreover, the easy fabrication and eco-friendliness of ND@MnO2 NS make it a rapid and simple method for detecting GSH. We envision the developed nanoprobe as an incredible platform for real-time monitoring of GSH levels in both extracellular and intracellular mediums, proving valuable for biomedical research and clinical diagnostics.

Highly Selective and Sensitive Non-enzymatic Glucose Biosensor Based on Polypyrrole-Borophene Nanocomposite

In this study, a non-enzymatic glucose sensor composed of two-dimensional (2D) borophene-decorated polypyrrole (PPy) nanocomposites (NCs) was developed. The PPy-borophene NCs were prepared using a low-cost sonication method. The sensing performance of the PPy-borophene NCs was investigated by the cyclic voltammetry (CV) technique against various biomolecules such as glucose, maltose, lactose, fructose, and urea. According to the electrochemical results, it was observed that in the glucose concentration range of 1.5 to 24 mM within a voltammetric cycle of 1 min, the PPy-based sensor and PPy-borophene NCs-based sensor exhibited sensitivities of 11.88 μAmM−1 cm−2 and 213.42 μAmM−1 cm−2, respectively. The detection limits of the PPy-based and PPy-borophene NCs-based sensors were determined to be 0.5 µM and 0.04 µM, respectively. Furthermore, selectivity measurement results revealed that the proposed non-enzymatic biosensor has remarkably good sensitivity and high selectivity, indicating that common biomolecules (glucose, maltose, lactose, fructose, and urea) could be captured by the sensor. Consequently, it was proven that the proposed biosensor could be a potential device for diabetes diagnosis.

A novel gold-decorated porous silicon-poly(3-hexylthiophene) ternary nanocomposite as a highly sensitive and selective non-enzymatic dopamine electrochemical sensor

As a key biomolecule for neurotransmission, dopamine (DA) is responsible for many neurological syndromes. Hence, effective DA detection is vital for the rapid-diagnosis of diseases caused by irregular DA levels. Therefore, we designed a non-enzymatic DA sensor using the novel gold-decorated porous silicon-poly-3-hexylthiophene (Au@PSi-P3HT) nanocomposite fabricated glassy carbon electrode. We employed a simple stain etching technique followed by ultra-sonication and photo-reduction techniques to synthesize this novel Au@PSi-P3HT nanocomposite. The structural, morphological, and surface characterizations of the Au@PSi-P3HT nanocomposite were performed using various analytical tools. TEM and FESEM images revealed that gold nanoparticles were randomly dispersed onto the PSi-P3HT sheet-like structure. In the electrochemical investigations, the Au@PSi-P3HT/GCE sensor showed excellent sensitivity (0.5112 μAμM−1cm−2), wide linear dynamic range (LDR = 1.0–460 μM), and reasonably low detection limit (LOD ∼0.63 μM). This newly designed DA sensor was also employed to check the potential chemical interference using several common biomolecules and the obtained results confirmed its selectivity during DA detection. The Au@PSi-P3HT/GCE sensor also exhibited satisfactory results in detecting DA levels in human blood serum and dopamine hydrochloride injection samples. Besides, the Au@PSi-P3HT/GCE sensor displayed superb reproducibility, repeatability, and stability. This novel Au@PSi-P3HT nanocomposite-modified GCE may emerge as a successful means for further designing effective non-enzymatic electrochemical sensors.

Black phosphorus nanosheets/poly(allylamine hydrochloride) based electrochemical immunosensor for the selective detection of human epididymis protein 4

In this work, an electrochemical immunosensor based on black phosphorus nanosheets (BPNS)/poly(allylamine hydrochloride) (PAH) nanocomposite modified glassy carbon electrode was developed for the detection of ovarian cancer biomarker HE4. PAH has been applied to retain BPNS in its original honeycomb structure and to anchor biomolecules electrostatically on the transducer surface. The as synthesized nanocomposite was characterized by zeta potential analysis, scanning electron microscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy. Subsequently, the performance of the electrochemical immunosensor was evaluated through cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. Under the optimal condition, the developed electrochemical immunosensor permitted to detect HE4 with a linear range of 0.1–300 ng ml−1 and a detection limit of 0.01 ng ml−1. The developed sensor exhibited good selectivity and specificity to HE4 with negligible interference effect from common biomolecules like bovine serum albumin, lysozyme, protamine, glucose, fructose, hemoglobin and fetal bovine serum. Further, practical application of developed electrochemical immunosensor was demonstrated in spiked human serum which showed satisfactory recovery percentages.

Metabolic profiling of serum and urine in preeclampsia and gestational diabetes in early pregnancy

PE and GDM are two major metabolic diseases affecting pregnancy. Individuals suffering from GDM are at an increased risk of developing PE in later gestational stages. Current study was done to evaluate first trimester serum and urine metabolome using nuclear magnetic resonance (NMR) spectroscopy to identify metabolites and pathways differentially regulated in both diseases. Serum metabolomics analysis revealed deregulation in larger group of metabolites and pathways as compared to urine between PE/GDM and NT groups. Few metabolites showed altered expression in both aliments. Perturbed metabolites have association with energy metabolism, protein metabolism, insulin sensitivity, gut microbiome and maintenance of redox balance. Deregulation in these metabolic pathways contributes to the pathology of GDM/PE. Our study revealed that serum metabolomic profile of PE and GDM shows overlap in 1st trimester of gestation. It also explored the potential of NMR metabolomics in identification of common biomolecules that could be developed into a clinical tool for early detection of both PE /GDM..

Comparative Account of Biomolecular Changes Post Epstein Barr Virus Infection of the Neuronal and Glial Cells Using Raman Microspectroscopy.

Raman microspectroscopy is a vibrational spectroscopy technique used for investigating molecular fingerprints of a wide range of liquid or solid samples. The technique can be efficiently utilized to understand the virus-mediated cellular changes and could provide valuable insights into specific biomolecular alterations. The Epstein Barr virus (EBV) has been associated with various types of cancers as well as neurodegenerative diseases. However, EBV-mediated neurological ailments are yet underexplored in terms of biomolecular changes in neuronal and glial cells (astrocytes and microglia). In continuation of our earlier exploration of EBV-influenced glial cells, we tried to decipher biomolecular changes in EBV-infected neuronal cells using Raman microspectroscopy. Additionally, we compared the consecutive biomolecular changes observed in neuronal cells with both the glial cells. We observed that EBV infection gets differentially regulated in the neuronal cells, astrocytes, and microglia. The viral entry and initiation of infection-mediated cellular modulation could start as soon as 2 h post infection but may regulate a distinct biomolecular milieu in different time intervals. Similar to the early timespan, the 24-36 h interval could also be important for EBV to manipulate neuronal as well as glial cells as depicted from elevated biomolecular activities. At these time intervals, some common biomolecules such as proline, glucose, lactic acid, nucleotides, or cholesterol were observed in the cells. However, at these time intervals, some distinct biomolecules were also observed in each cell, such as collagen, lipid, and protein stretches in the neuronal nucleus (2-4 h); tyrosine and RNA in the astrocyte nucleus (2-4 h nucleus); and fatty acids in the microglia nucleus (24-36 h). The observed biomolecular entities could ultimately play pivotal roles in the viral usurpation of cells. We also provided insights into whether these biomolecular changes can be correlated to each other and mediate virus-associated manifestations which can be linked to neurological complications. Our study aids in the understanding of EBV-mediated biomolecular changes in the various compartments of the central nervous system.

Recent advances in nanostructured transition metal sulfide based sensors for environmental applications

It is well said by the great writer Rumi that “Anything beyond what we need is a poison”. The adulteration of living conditions or the environment due to the presence of several toxic chemicals has adversely affected the quality of life. These chemicals can be anything like pesticide, industrial waste, organic contaminants, toxic gases, pharmaceuticals or even the common biomolecules. Even the slight perturbation in their concentration may have harmful consequence on human health. The development of sensors to monitor their levels in the environment is the first step to deal with them. Continuous efforts are being made to find suitable sensing materials as the need of hour. Nanostructured metal sulfides owing to their versatile properties are a suitable candidate for sensing applications. This review presents a recent perspective to the use of metal sulphide for sensing of a wide range of analytes.

Selection and identification of a DNA aptamer for ultrasensitive and selective detection of λ-cyhalothrin residue in food

Pyrethroid pesticides residues will not only pollute the environment, but also cause high toxicity to the human body. It is significant to establish an efficient and accurate method for pyrethroid detection in food. Considering that the common biomolecules like antibody is complicated and easy to inactivate, it is urgent to find a new type of biomolecule to specifically recognize pyrethroid pesticides. This study proposed the Capture-SELEX strategy to firstly select λ-cyhalothrin aptamer by immobilizing random ssDNA library. High-throughput sequencing was performed on the enriched ssDNA library through multiple Capture-SELEX rounds. Comprehensively inspecting structural similarity and homology, six sequences were chosen from five families for further analysis. The results showed that the aptamer (named LCT-1) could specifically recognize λ-cyhalothrin with the strongest affinity (Kd = 50.64 ± 4.33 nmol L−1). Molecular docking results revealed that the binding sites between λ-cyhalothrin and LCT-1 aptamer are mainly related to the bases A-5, C-6, C-28, A-29, C-30, G-31 and G-32. The LCT-1 aptamer was truncated to a shorter sequence (named as LCT-1-39) by removing other irrelevant bases, and its Kd value was determined as (10.27 ± 1.33) nmol·L−1 by Microscale Thermophoresis (MST). Both LCT-1 and LCT-1-39 aptamers were employed as recognition molecules to establish the colorimetric aptasensors for λ-cyhalothrin detection, which displayed good repeatability and reproducibility. The detection limit of the aptasensors were individually calculated as 0.0197 μg ml−1 and 0.0186 μg ml−1, and their recovery rate of λ-cyhalothrin in pear and cucumber samples was in the range of 82.93–95.50%. This article provides a promising application for the detection of λ-cyhalothrin.

Regulation of redox signaling by reactive sulfur species

Reactive sulfur species, such as cysteine persulfide, are produced endogenously at significant levels in cells and have rapidly emerged as common biomolecules. By virtue of improved analytical methods for detecting reactive persulfides, it has been demonstrated that these reactive molecules exhibit unique chemical properties and are present in various forms in vivo. Accumulating evidence has suggested that persulfides may be involved in a variety of biological processes, such as anti­oxidant and anti-inflammatory responses, biosynthesis of sulfur-containing molecules, mitochondrial energy metabolism via sulfur respiration, and cytoprotection via regulation of redox signal transduction induced by endogenous and exogenous electrophiles. Elucidation of the persulfide-dependent metabolism of redox signals is expected to facilitate our understanding of the importance of persulfides in regulating redox signals.

Ruthenium polypyridyl complex-containing bioconjugates

• Bioconjugation improves some of the features of Ru(II) polypyridyl complexes • The intrinsic properties of the complexes are not usually altered by the bioconjugation. • Peptides are among the most common biomolecules used in bioconjugation with Ru(II) complexes. • The bioconjugates were used for different purposes. In the last decades, the number of articles describing the synthesis, characterization and applications of ruthenium polypyridyl complexes has significantly increased. One of the reasons is their tuneable, outstanding luminescent properties. However, ruthenium polypyridyl complexes usually have no intrinsic selectivity towards cancer cells, making them impractical, for example, in certain biological applications. To overcome this drawback, these complexes have been conjugated to biomolecules. In this review, we describe the different ruthenium polypyridyl complex-containing bioconjugates reported so far and their applications as, for example, anticancer drug candidates, sensors or biocatalysts. However, we are not reviewing ruthenium-containing nucleotides and DNA conjugates since these topics were recently reported. The multiple ways of attaching the biomolecules (i.e., peptides, antibodies, carbohydrates, lipids and vitamins) to the ruthenium core are also summarized.

Graphene Oxide and Reduced Derivatives, as Powder or Film Scaffolds, Differentially Promote Dopaminergic Neuron Differentiation and Survival.

Emerging scaffold structures made of carbon nanomaterials, such as graphene oxide (GO) have shown efficient bioconjugation with common biomolecules. Previous studies described that GO promotes the differentiation of neural stem cells and may be useful for neural regeneration. In this study, we examined the capacity of GO, full reduced (FRGO), and partially reduced (PRGO) powder and film to support survival, proliferation, differentiation, maturation, and bioenergetic function of a dopaminergic (DA) cell line derived from the mouse substantia nigra (SN4741). Our results show that the morphology of the film and the species of graphene (GO, PRGO, or FRGO) influences the behavior and function of these neurons. In general, we found better biocompatibility of the film species than that of the powder. Analysis of cell viability and cytotoxicity showed good cell survival, a lack of cell death in all GO forms and its derivatives, a decreased proliferation, and increased differentiation over time. Neuronal maturation of SN4741 in all GO forms, and its derivatives were assessed by increased protein levels of tyrosine hydroxylase (TH), dopamine transporter (DAT), the glutamate inward rectifying potassium channel 2 (GIRK2), and of synaptic proteins, such as synaptobrevin and synaptophysin. Notably, PRGO-film increased the levels of Tuj1 and the expression of transcription factors specific for midbrain DA neurons, such as Pitx3, Lmx1a, and Lmx1b. Bioenergetics and mitochondrial dysfunction were evaluated by measuring oxygen consumption modified by distinct GO species and were different between powder and film for the same GO species. Our results indicate that PRGO-film was the best GO species at maintaining mitochondrial function compared to control. Finally, different GO forms, and particularly PRGO-film was also found to prevent the loss of DA cells and the decrease of the α-synuclein (α-syn) in a molecular environment where oxidative stress has been induced to model Parkinson's disease. In conclusion, PRGO-film is the most efficient graphene species at promoting DA differentiation and preventing DA cell loss, thus becoming a suitable scaffold to test new drugs or develop constructs for Parkinson's disease cell replacement therapy.

Gold nanoparticles plated porous silicon nanopowder for nonenzymatic voltammetric detection of hydrogen peroxide

A voltammetric approach was developed for the selective and sensitive determination of hydrogen peroxide using Au plated porous silicon (PSi) nanopowder modified glassy carbon electrode (GCE). The AuNPs-PSi hybrid structure was synthesized via stain etching procedure followed by an immersion plating method to deposit AuNPs onto PSi via a simple galvanic displacement reaction with no external reducing agent to convert Au3+ to Au0. The as-fabricated AuNPs-PSi catalyst was successfully characterized by XRD, Raman, FTIR, XPS, SEM, TEM and EDS techniques. Well crystalline nature of the as-fabricated hybrid structure with AuNPs size ranging from 5 to 40 nm was observed. The specific surface area and total pore volume for both PSi and AuNPs plated PSi were evaluated using N2 adsorption isotherm technique. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were applied to investigate the catalytic efficiency of AuNPs-PSi modified electrode compared to pure PSi/GCE and unmodified GCE. The sensing performance of the active material modified GCE was thoroughly examined with linear sweep voltammetry (LSV) and square wave voltammetry (SWV) techniques. The AuNPs-PSi/GCE exhibited a remarkable linear dynamic range between 2.0 and 13.81 mM (for LSV) and 0.5–6.91 mM for (SWV) with high sensitivity and low detection limit of 10.65 μAmM−1cm−2 and 14.84 μM for LSV, whereas 10.41 μAmM−1cm−2 and 15.16 μM using SWV techniques, respectively. The fabricated sensor electrode showed excellent anti-interfering ability in the presence of several common biomolecules as well as demonstrated good operational stability and reproducibility with low relative standard deviation. Moreover, the modified electrode showed acceptable recovery of H2O2 in a real sample analysis. Thus, the developed AuNPs-PSi hybrid nanomaterial represents an excellent electrocatalyst for the efficient detection and quantification of H2O2 by the electrochemical approach.

Distinct carbon fractions drive a generalisable two‐pool model of fungal necromass decomposition

Abstract Fungi represent a rapidly cycling pool of carbon (C) and nitrogen (N) in soils. Understanding of how this pool impacts soil nutrient availability and organic matter fluxes is hindered by uncertainty regarding the dynamics and drivers of fungal necromass decomposition. Here we assessed the generality of common models for predicting mass loss during fungal necromass decomposition and linked the resulting parameters to necromass substrate chemistry. We decomposed 28 different types of fungal necromass in laboratory microcosms over a 90‐day period, measuring mass loss on all types, and N release on a subset of types. We characterised the initial chemistry of each necromass type using: (a) fibre analysis methods commonly used for plant tissues, (b) initial melanin and nitrogen (N) concentrations and (c) Fourier transform infrared (FTIR) spectroscopy to assess the presence of bonds associated with common biomolecules. We found universal support for an asymptotic model of decomposition, which assumes that fungal necromass consists of an exponentially decomposing ‘fast’ pool, and a ‘slow’ pool that decomposes at a rate approaching zero. The strongest predictor of the fast pool decay rate (k) was the proportion of cell soluble components, though initial N concentration also predicted k, albeit more weakly. The size of the slow pool was best predicted by the acid non‐hydrolysable fraction, which was positively correlated with melanin‐associated aromatics. Nitrogen dynamics varied by necromass type, ranging from net N release to net immobilisation. The maximum quantity of N immobilised was inversely related to cell soluble contents and k, as positively related to FTIR spectra associated with cell wall polysaccharides. Collectively, our results indicate that the decomposition of fungal necromass in soils can be described as having two distinct stages that are driven by different components of substrate C chemistry, with implications for rates of N availability and organic matter accumulation in soils. A free Plain Language Summary can be found within the Supporting Information of this article.

Photoelectrochemical determination of oxidase activity based on photoinduced direct electron transfer of protein by using a convenient photoelectrochemical detector

In order to fabricate the enzyme-labelled photoelectrochemical biosensor without redox mediators, a new method using chitosan to dissolve samples and transmit electrons was proposed to achieve the direct electron transfer between the oxidase and ZnO nanorods photoelectrode. Based on this strategy, activities of glucose oxidase and cholesterol oxidase were determined through using a novel photoelectrochemical detector matched with the method. Under optimized experimental conditions, the logarithm of photocurrent increase displayed a linear relationship to the logarithm of glucose oxidase or cholesterol oxidase concentrations in the range from 0.1–2.50 U/mL or from 0.1–4.00 U/mL, respectively, with correlation coefficients of 0.9976 and 0.9968, and the detection limits estimated by the correction curves were 0.05 and 0.08 U/mL. The results of the investigation further showed that the relative standard deviation was less than 5.8 % for the determination of commercial products with the recovery of 95 % ∼ 108 %. Besides peroxidase, the proposed method has a good selectivity for common biomolecules, and the relative standard deviation was less than 4.76 % for the repeated determinations.

Screening polymeric ionic liquids for chromatography-based purification of bacteriophage M13

M13 bacteriophage is a key instrument in phage display applications, as well as a possible antibacterial therapeutic agent due to its highly restrictive bacterial pathogenesis, and other applications. The traditional phage purification process is usually achieved by gradient ultracentrifugation or a combination of precipitation, centrifugation and microfiltration. These approaches easily lead to long process times, high operational costs, phage aggregation and consequent product loss (approximately 60%). This work is thus focused on an alternative potential large-scale process to achieve high yield and purity while minimizing the operational costs.Electrostatic-based separation processes are also common biomolecules purification techniques. Although anion exchange chromatography has been used before to purify several viral particles, this technique has been poorly reported for the purification of M13 phage. In a recent work, our group has demonstrated the use of a predominant anion exchange process, where a polymeric ionic liquid (PIL) was used as an alternative separation matrix for M13 bacteriophage. In this work, a variety of system parameters was studied, including chemical structure of the cation and the anion, the crosslinker nature and its concentration, either in batch adsorption/elution or chromatographic operation mode. The PIL-based chromatographic operation mode revealed to be a suitable separation process for M13 from directly filtered E. coli supernatant, reaching over 70% M13 recovery and 4.6 purification factor in a single step. To our knowledge, this is the first time that PILs have been reported as separation agents for bioproducts from complex mixtures.

High-sensitivity Detection of Cysteine and Glutathione Using Au Nanoclusters Based on Aggregation-induced Emission.

Gold nanoclusters (AuNCs) stabilized by glutathione (GSH) have been synthesized using a simple one-pot method, which were used as a fluorescence-enhanced probe for the detection of cysteine (Cys) and GSH. The detection is based on the finding that the weak yellow fluorescence of the AuNCs, with excitation/emission maxima of 430/600nm, can be enhanced by Cys and GSH via NCs aggregation. This method is selective for Cys and GSH. According to the fluorescence enhancement, the detection ranges of AuNCs for Cys and GSH are 2.49µM ~ 0.80mM and 1.99µM ~ 0.44mM, with the detection limit of 0.42µM and 0.27µM, respectively. In addition, the probe has good anti-interference performance over other common biomolecules. Importantly, the probe is successfully used for the determination of Cys in human serum samples, displaying the potential application of the probe in the detection of biological sulfhydryl molecules in actual samples.

Impact of Viral Lysis on the Composition of Bacterial Communities and Dissolved Organic Matter in Deep-Sea Sediments.

Viral lysis is a main mortality factor for bacteria in deep-sea sediments, leading to changing microbial community structures and the release of cellular components to the environment. Nature and fate of these compounds and the role of viruses for microbial diversity is largely unknown. We investigated the effect of viruses on the composition of bacterial communities and the pool of dissolved organic matter (DOM) by setting up virus-induction experiments using mitomycin C with sediments from the seafloor of the Bering Sea. At the sediment surface, no substantial prophage induction was detected, while incubations from 20 cm below seafloor showed a doubling of the virus-to-cell ratio. Ultra-high resolution mass spectrometry revealed an imprint of cell lysis on the molecular composition of DOM, showing an increase of molecular formulas typical for common biomolecules. More than 50% of these compounds were removed or transformed during incubation. The remaining material potentially contributed to the pool of refractory DOM. Next generation sequencing of the bacterial communities from the induction experiment showed a stable composition over time. In contrast, in the non-treated controls the abundance of dominant taxa (e.g., Gammaproteobacteria) increased at the expense of less abundant phyla. Thus, we conclude that viral lysis was an important driver in sustaining bacterial diversity, consistent with the “killing the winner” model.