Digestive Cycle Research Articles

The Impact of an Earthworm Digestion on the Chemical Compositions of Various Clay Minerals from Soils

Aims: The impact of living organisms activities in soils may generate various chemical and mineralogical changes. The objective of this study is to estimate the impact of earthworms on the chemistry of soil minerals such as the clay minerals. Study Design: An experiment was carried out integrating earthworms and clay minerals. The modifications due to this interaction between minerals and organic matter induced by earthworms’ digestion are discussed. Place and Duration of Study: Institut des Sciences de la Terre et de l’Environnement (UdS/CNRS), Université de Strasbourg, Strasbourg, France. Eight weeks of experiment for each type of clay. Methodology: The earthworm Lumbricus terrestris was used for digestion of illite and various smectite-type minerals, with or without peat moss, during a laboratory experiment at a constant temperature of 20°C during 8 weeks and under artificial 12 hour-light and 12 hour-dark cycles, for each digestion cycle. Results: The chemical elements extracted from smectites by the earthworm digestion appear to be mineral dependent. The behavior of K and radiogenic 40Ar is more dictated by the type of digested mineral than by the digestion process itself. The 87Sr/86Sr ratio of the acid leachates of the nontronite and peat mixture, before and after digestion, suggests that half of the digested matter corresponds to the digestive action of the earthworms, with the second half resulting from food. Digested clay material represents up to 30% and the peat moss the remainder of the mixtures. Conclusion: This study highlights the role of organic compounds generated by earthworms activities in transfer of elements to surface waters and soil fluids.

Exonuclease III-propelled DNAzyme walker: an electrochemical strategy for microRNA diagnostics.

MicroRNA detection is crucial for early infectious disease diagnosis and rapid cancer screening. However, conventional techniques like reverse transcription-quantitative polymerase chain reaction, requiring specialized training and intricate procedures, are less suitable for point-of-care analyses. To address this, we've developed a straightforward amplifier based on an exonuclease III (exo III)-propelled DNAzyme walker for sensitive and selective microRNA detection. This amplifier employs a specially designed hairpin probe with two exposed segments for strand recognition. Once the target microRNA is identified by the hairpin's extended single-strand DNA, exo III initiates its digestion, allowing microRNA regeneration and subsequent hairpin probe digestion cycles. This cyclical process produces a significant amount of DNAzyme, leading to a marked reduction in electrochemical signals. The biosensor exhibits a detection range from 10 fM to 100pM and achieves a detection limit of 5 fM (3σcriterion). Importantly, by integrating an "And logic gate," our system gains the capacity for simultaneous diagnosis of multiple microRNAs, enhancing its applicability in RNA-based disease diagnostics.

A sensitive “off-on” electrochemiluminescence DNA sensor based on signal cascade amplification circuit and distance-dependent energy transfer

A sensitive “off-on” electrochemiluminescence (ECL) DNA sensor was constructed based on Exo III-assisted cascade amplification system. In the cascade amplification circuit, target DNA and Exo III cutting substrate were designed into an inverted T-shaped binding mode to form a stable DNA junction, thus effectively triggering Exo III digestion cycle. During the biosensor assembly process, ferrocene (Fc) and distance-dependent ECL resonance energy transfer (ECL-RET) and surface plasmon resonance (SPR) effects were introduced to regulate the ECL of semiconductor quantum dots (QDs). Carboxylated ZnCdSe/ZnS QDs were used as ECL signal probes and K2S2O8 was coreactant, and the initial cathodic ECL signal of QDs was efficiently quenched through electron and energy transfer with Fc and ECL-RET with Au NPs, leaving the system in “off” state. After the products of cascade amplification were introduced into the electrode surface, the single-stranded DNA modified with Fc was displaced, and the distance between Au NPs and QDs became farther, resulting in a transition from ECL-RET to SPR, and then a significant ECL signal boost was achieved, turning the system into “on” state. The combination of efficient cascade amplification system and sensitive “off-on” ECL signal change mode enabled the biosensing platform to detect target DNA with high selectivity (able to distinguish single-base mutated DNA) and ultra-high sensitivity (limit of detection was 31.67 aM, S/N = 3), providing a new perspective for designing highly sensitive and programmable ECL biosensors.

An 11-point time course midgut transcriptome across 72 h after bloodfeeding provides detailed temporal resolution of transcript expression in the arbovirus vector, Aedes aegypti.

As the major vector for dengue, Zika, yellow fever, and chikungunya viruses, the mosquito Aedes aegypti is one of the most important insects in public health. These viruses are transmitted by bloodfeeding, which is also necessary for the reproduction of the mosquito. Thus, the midgut plays an essential role in mosquito physiology as the center for bloodmeal digestion and as an organ that serves as the first line of defense against viruses. Despite its importance, transcriptomic dynamics with fine temporal resolution across the entire digestion cycle have not yet been reported. To fill this gap, we conducted a transcriptomic analysis of A. aegypti female midguts across a 72-h bloodmeal digestion cycle for 11 time points, with a particular focus on the first 24 h. PCA analysis confirmed that 72 h is indeed a complete digestion cycle. Cluster and GO enrichment analysis showed the orchestrated modulation of thousands of genes to accomplish the midgut's role as the center for digestion, as well as nutrient transport with a clear progression with sequential emphasis on transcription, translation, energy production, nutrient metabolism, transport, and finally, autophagy by 24-36 h. We further determined that many serine proteases are robustly expressed as if to prepare for unexpected physiological challenges. This study provides a powerful resource for the analysis of genomic features that coordinate the rapid and complex transcriptional program induced by mosquito bloodfeeding.

Anaerobic co-digestion of food waste, bio-flocculated sewage sludge, and cow dung in CSTR using E(C2)Tx synthetic consortia

In the current study, a E(C2)Tx synthetic consortia was tested for anaerobic co-digestion of food waste (FW), bio-flocculated sewage sludge (BFS)/ raw wastewater (RW) and cow dung (CD) at varying proportions in 0.25 L and 6.5 L mesophilic continuously stirred tank reactors. Anaerobic co-digestion of FW with CD and RW at the ratio of 1:1:8 in 0.25 L batch-reactor with E(C2)Tx inoculum resulted in the highest H2 production with least CO2 release. The microbial dynamics of FW:CD:RW samples were studied using 16S metagenomic sequencing which indicated a predominance of hydrolysing microbes at the end point of the digestion cycle. Subsequently, the experiments were scaled up in two continuous digesters, namely, R1 (fed with 50% FW and 50% BFS) and R2 (fed with 2% FW and 98% BFS) with 6.5 L working volume at 2.5 g VS L−1D−1 organic loading rate (OLR) for 120 days. The highest VFA production of 19,183 mg L−1 and 3,265 mg L−1 with maximum bio-methane yield of 142.21- and 225.03-mL CH4g−1 VSadded were recorded in reactors R1 and R2, respectively. In addition, a numerical analysis was conducted to visualize the mixing and temperature distribution within the digesters, and the velocity and temperature profiles were obtained using Ansys Fluent.

Design and Employing of a Non-Linear Response Surface Model to Predict the Microbial Loads in Anaerobic Digestion of Cow Manure: Batch Balloon Digester

Biogas is among the sources of renewable energy with a great potential to mitigate global energy challenges by virtue of the ease of implementation of the technology. The study focused on monitoring the total viable bacteria counts with the number of days, daily average ambient temperature and pH from a balloon type biodigester fed with 2500 L of cow manure (500 L of slurry each day for five successive days) with six months retention time using data acquisition system, standard methods and mathematical model. A non-linear response surface model was developed to predict the total viable bacteria counts with the predictors. The predictors were ranked by weights of importance to the desired targets by reliefF test. At the end of the anaerobic digestion cycle the cumulative volume of biogas was 6.75 m3 with 65.8% methane and 31.2% carbon dioxide. The ranking by weights of the predictors revealed that all the input parameters were primary factors and number of days contributed the most. Based on the testing data set, the response surface model was capable of predicting the total viable bacteria counts with high accuracy as the determination coefficient, root mean square error and p-value were 0.959, 0.197 and 0.602.

Fabrication of multi-functional CuO@PDA-MoS2 mediated dual-functional fluorescence Aptamer for the detection of Hg2+ ions and chloramphenicol through desulfurization cleavage reaction and exonuclease I activity

We progress a new sensor probe for the simultaneous detection of Hg2+ ions and chloramphenicol (CAP) by integrating FAM and TAMRA fluorophore labelled phosphorothioate RNA modified *ssDNA (*-PS probe) and CuO@PDA-MoS2 nanosphere. This work also stated a simplistic method to prepare CuO@PDA-MoS2 nanosphere via in-situ growth of MoS2 on the CuO@PDA nanosphere. The multi-functional CuO@PDA-MoS2 having rich binding sites with nanoscale architecture display great potential as an adsorbents for FAM-*ssDNA-TAMRA owing to the several interaction between them. This is lead to robustly quenching the fluorophores emission and minimizing the signal to noise ratio because of the FRET mechanism. In the developed sensor probe consisted of two interaction sections: Hg2+-induced cleavage of the PS-probe can efficiently liberates the FAM fluorophore, leads to remarkable enhancement of FAM emission. Second, the CAP can preferentially bind with remaining ssDNA-TAMRA and the formed CAP-ssDNA-TAMRA complex can be released from CuO@PDA-MoS2 surface, resulting in the regaining of TAMRA emission. Sequentially, the introduction of Exo I is to prompt and digest the CAP-ssDNA-TAMRA complex, caused in the significant regaining of TAMRA emission. Concurrently, the released CAP mediates a new digestion cycle, tends to result in ultra-trace detection of CAP. Under optimal circumstances, the suggested detecting scheme remarkably achieved for the extremely sensitive and selective detection of Hg2+ and CAP with in a wide linear range (0–10 nM Hg2+ and 0–5 nM CAP) and limit of detection 86 and 45 pM, respectively. Our current method is simpler and less expensive than existing methods of detecting Hg2+ and CAP in real water samples. More importantly, the presented approach can be detect the targets simultaneously and/or sequentially without loss of detection accuracy.

Molecular complexity and gene expression controlling cell turnover during a digestive cycle of carnivorous sponge Lycopodina hypogea.

Lycopodina hypogea is a carnivorous sponge that tolerates laboratory husbandry very well. During a digestion cycle, performed without any digestive cavity, this species undergoes spectacular morphological changes leading to a total regression of long filaments that ensure the capture of prey and their reformation at the end of the cycle. This phenomenon is a unique opportunity to analyze the molecular and cellular determinants that ensure digestion in the sister group of all other metazoans. Using differential transcriptomic analysis coupled with cell biology studies of proliferation, differentiation, and programmed cell deaths (i.e., autophagy and the destructive/constructive function of apoptosis), we demonstrate that the molecular and cellular actors that ensure digestive homeostasis in a sister group of all remaining animals are similar in variety and complexity to those controlling tissue homeostasis in higher vertebrates. During a digestion cycle, most of these actors are finely tuned in a coordinated manner. Our data benefits from complementary approaches coupling in silico and cell biology studies and demonstrate that the nutritive function is provided by the coordination of molecular network that impacts the cells turnover in the entire organism.

DNA Hairpins and Dumbbell-Wheel Transitions Amplified Walking Nanomachine for Ultrasensitive Nucleic Acid Detection.

Nucleic acids, including circulating tumor DNA (ctDNA), microRNA, and virus DNA/RNA, have been widely applied as potential disease biomarkers for early clinical diagnosis. In this study, we present a concept of DNA nanostructures transitions for the construction of DNA bipedal walking nanomachine, which integrates dual signal amplification for direct nucleic acid assay. DNA hairpins transition is developed to facilitate the generation of multiple target sequences; meanwhile, the subsequent DNA dumbbell-wheel transition is controlled to achieve the bipedal walker, which cleaves multiple tracks around electrode surface. Through combination of strand displacement reaction and digestion cycles, DNA monolayer at the electrode interface could be engineered and target-induced signal variation is realized. In addition, pH-assisted detachable intermolecular DNA triplex design is utilized for the regeneration of electrochemical biosensor. The high consistency between this work and standard quantitative polymerase chain reaction is validated. Moreover, the feasibilities of this biosensor to detect ctDNA and SARS-CoV-2 RNA in clinical samples are demonstrated with satisfactory accuracy and reliability. Therefore, the proposed approach has great potential applications for nucleic acid based clinical diagnostics.

Analysis of glycan ratio of Chinese hamster ovary cell-cetuximab antigen-binding segment via rapid enzyme digestion with endo-β-N-acetylglucosaminidase F

西妥昔单抗具有较复杂的糖基化修饰,在抗原结合片段(Fab)和可结晶片段(Fc)的重链上都含有2个N-糖基化位点,其中Fab段的糖基化最为复杂,要研究清楚该位点的糖基化修饰,开发专一性切糖技术和稳定的聚糖比例分析方法是当前迫切需要解决的难题。以中国仓鼠卵巢(CHO)细胞表达的西妥昔单抗为研究对象,使用β-N-乙酰氨基葡萄糖苷酶(Endo F2)开发了一种快速Fab段聚糖释放的方法,利用超高效液相色谱-高分辨质谱(UPLC-HRMS)进行了定性和聚糖比例分析。第一步对抗体原液进行非变性酶切,抗体原液经超纯水稀释后,加入糖苷酶Endo F2进行酶切,通过质谱对质量数的解析,结果表明Endo F2酶切时间5 min, Fab段的聚糖就能完全切除,而Fc段的聚糖不受影响,实现了快速酶切,而且切糖具有很好的专一性。第二步对Fab段聚糖进行比例分析,将释放的聚糖经对氨基苯甲酰胺(2-AB)荧光标记后使用超高效液相色谱联用荧光检测器(FLR)进行检测,在亲水作用色谱(HILIC)柱上得到良好的分离并可以进行稳定地聚糖比例分析。3次独立试验结果表明,酶切后的质谱图基本一致,且聚糖的比例结果也基本一致,表明Endo F2酶切方法和聚糖比例分析方法都具有较好的稳定性和可靠性。此外,通过测定来自两个不同工艺生产的样品,数据显示两者的糖谱上具有非常明显的差异,表明利用开发的方法可以实现对抗体生产工艺进行监测研究,对抗体生产工艺的评估具有非常重要的意义。

Dual-mode amplified fluorescence oligosensor mediated MOF-MoS2 for ultra-sensitive simultaneous detection of 17β -estradiol and chloramphenicol through catalytic target- recycling activity of exonuclease I

The research outlines a novel ultrasensitive oligosensor which was designed by FRET-based selective simultaneous detection of multiple organic pollutant (chloramphenicol (CP) and 17β-estradiol (17E)) utilizing the MOF-MoS2 nanomaterial with Exo I signal amplification and target recycling strategy. In this oligosensor, the specific oligomers of 17E (ROX-SSO) and CP (TAMRA-SSO) are used as the recognition parts and the ROX and TAMRA as the fluorescent probes. The cubic-MOF incorporated by a few layered MoS2 sheets (MOF-MoS2) is used as oligomer adsorbing material and an efficient fluorescent nanoquencher for reducing the background signal. In this detection approach, the ROX-SSO and TAMRA-SSO probes could be adsorbed on the surface of the MOF-MoS2 through π-stacking and Vander Waals interactions. At the same time, the fluorescence of the ROX and TAMRA could be efficiently quenched due to the energy transfer between fluorophores and MOF-MoS2. In the addition of 17E & CP, the specific oligomers can be preferentially bound with the 17E & CP, and the newly formed ROX-SSO-17E &TAMRA-SSO-CP complex can be released from the MOF-MoS2 surface and the partial recovery of fluorescence signal. Subsequently, the addition of Exo I is to trigger and digest the ROX-SSO-17E &TAMRA-SSO-CP complex, resulted in the remarkable recovery of fluorescence emission. At the same time, the liberated targets mediate a new cycle of digestion, resulting in the ultra-trace detection of targets. Thus, with the aid of the helper MOF-MoS2 the turn-on detection of 17E and CP may be easily accomplished by observing the fluorescence signal of the respective fluorophores from “off” to “on”. Under optimal circumstances, the oligosensor has an excellent accuracy of 17E and CP, with detection limits of 180 and 200 pM, respectively. Furthermore, for the first time, the research successfully utilized this oligosensor to detect 17E and CP in milk, honey and water samples.

Mycobacterium tuberculosis piezoelectric sensor based on AuNPs-mediated enzyme assisted signal amplification

Rapid diagnosis of tuberculosis disease (TB) still remained a pressing need for TB control efforts all over the world. However, the existing detection approaches cannot satisfy demand of rapid detection of clinical Mycobacterium tuberculosis (M. tuberculosis) because of the long detection time and high cost. Herein, we proposed a new M. tuberculosis piezoelectric sensor based on AuNPs-mediated enzyme assisted signal amplification. A hairpin-shaped DNA duplex with a protrusion of the 3′ end was designed. In the presence of specific 16 S rDNA fragment of M. tuberculosis, the hairpin probe was opened, which triggered the selective cleavage of hairpin probe by Exonuclease III (Exo III), resulting in the release of uncut DNA probe and target DNA. The released target DNA hybridized with another hairpin-shaped DNA duplex, and a new digestion cycle was started, thus generating large amounts of uncut DNA probes. The uncut DNA was pulled to the electrode surface by the hybridization with capture probe modified on the electrode. Subsequently detection probe labeled AuNPs was hybridized with uncut DNA and entered between the two electrodes. The AuNPs linked to hybridized detection probe were grown in the HAuCl4 and Nicotinamide adenine dinucleotide (NADH) solution and offered the conductive connection between the gaps of electrode. The changes were monitored by the piezoelectric sensor. The piezoelectric biosensor could achieve a detection of M. tuberculosis (102–108 CFU mL−1) within 3 h, the detection limit (LOD) was 30 CFU mL−1. The methodology could be transformed into different microbial targets, which is suitable for further development of small portable equipment and multifunctional detection.

Insights into the local interaction mechanisms between fermenting broken maize and various binder materials for anaerobic digester structures

Concrete structures of anaerobic digestion plants face chemically aggressive conditions due to the contact with the complex liquid fraction of the fermenting biowaste. This paper aims to determine the biogeochemical dynamic interaction phenomena at play between the biowaste and cementitious matrices at the local scale, and to identify durable binders in such environments. Binder materials likely to show increased durability – slag and calcium aluminate cement, and a metakaolin-based alkali-activated geopolymer – and a reference Portland cement were inserted into sealed bioeactors during 5 cycles (245 days) of broken maize anaerobic digestion. Cementitious pastes suffered chemical and mineralogical alteration related mainly to carbonation and leaching. However, they had no negative impact on the bioprocess in terms of pH, metabolic evolution of volatile fatty acids and NH4+, planktonic microbial community composition or CH4 production. In all reactors, the microbial community was able to perform the anaerobic digestion successfully. The MKAA was only slightly altered in its outermost layer. Its presence in the biowaste induced lower NH4+ concentrations, a slightly higher pH and a marked shift in the microbial community, but CH4 total production was not affected. Substantial enrichment of acid forming bacteria, especially members of the genus Clostridium, was observed in the biofilm formed on all materials.

Self-paired dumbbell DNA -assisted simple preparation of stable circular DNAzyme and its application in Pb2+ sensor

During its development in recent decades, DNAzyme has become a promising candidate for application in biosensor field. However, it still suffers from the problem of thermodynamic and biological instability such as nuclease digestion, which limits its applications in complex samples. Here we have presented a simple and common strategy to resolve this problem by engineering the linear DNAzyme into a circular shape DNAzyme based on the integration of substrate and enzyme parts into one single-stranded sequence. This circular DNAzyme system is indeed endowed with excellent stability due to the stable intramolecular double-stranded formation and extraordinary resistance to nuclease digestion due to the closed structure. We demonstrated that this circular DNAzyme system gained excellent stability and could active under conditions across a broader range of temperature, salt concentrations, and pH. Depending on this circular DNAzyme, combing with Terminal deoxynucleotidyl transferase (TdT)-generated G-quadruplexes, a label free colorimetric sensing platform for Pb2+ quantitation was developed, and a detection limit of 0.085 nM was achieved. Then the enzyme digestion cycle amplification was introduced to further improve the sensitivity of the sensing system, an ultralow detection limit of 0.0015 nM for this fluorescence method was achieved. Based on the two sensing platforms, ultrasensitive analysis of Pb2+ in environmental water and food samples was successfully realized. It is anticipated that this stable circular DNAzyme design will be helpful for trace detection in complex samples.

A novel framework for engineering protein loops exploring length and compositional variation

Insertions and deletions (indels) are known to affect function, biophysical properties and substrate specificity of enzymes, and they play a central role in evolution. Despite such clear significance, this class of mutation remains an underexploited tool in protein engineering with few available platforms capable of systematically generating and analysing libraries of varying sequence composition and length. We present a novel DNA assembly platform (InDel assembly), based on cycles of endonuclease restriction digestion and ligation of standardised dsDNA building blocks, that can generate libraries exploring both composition and sequence length variation. In addition, we developed a framework to analyse the output of selection from InDel-generated libraries, combining next generation sequencing and alignment-free strategies for sequence analysis. We demonstrate the approach by engineering the well-characterized TEM-1 β-lactamase Ω-loop, involved in substrate specificity, identifying multiple novel extended spectrum β-lactamases with loops of modified length and composition—areas of the sequence space not previously explored. Together, the InDel assembly and analysis platforms provide an efficient route to engineer protein loops or linkers where sequence length and composition are both essential functional parameters.

“Spitting as traditional medicine” – why alpha-emitting nanoparticulates make spitting an unfortunate but significant contribution to health

Spitting is a human reflex as old as civilization, related, mainly, as is shown, to the evacuation of internal contamination with alpha-emitting nanoparticulates, a contamination with many causes, from car fumes and industrial smokes, coal ashes and cement, radon, phosphated fertilizers, to depleted uranium weapons and natural dust and tap water in areas of high natural radioactivity, as well as cigarettes, for the main sources. Strong levels of coal ash pollution together with high natural radioactivity explain for instance the spitting “custom” in Chinese streets, together with long distances between workplace and home, widespread cigarette use, and lack of public toilets. Alphaemitting nanoparticulates become a part of the digestion cycle in meat-eaters, but not without collateral damage.

Blast-furnace slag cement and metakaolin based geopolymer as construction materials for liquid anaerobic digestion structures: Interactions and biodeterioration mechanisms

In order to promote the development of the biogas industry, solutions are needed to improve concrete structures durability in this environment. This multiphysics study aims to analyse the multiphases interactions between the liquid phase of an anaerobic digestion system and cementitious matrices, focusing on (i) the impacts of the binder nature on the anaerobic digestion process at local scale, and (ii) the deterioration mechanisms of the materials. Cementitious pastes made of slag cement (CEM III), innovative metakaolin-based alkali-activated material (MKAA), with compositions presumed to resist chemically aggressive media, and a reference binder, ordinary Portland cement (CEM I), were tested by immersion in inoculated cattle manure in bioreactors for a long period of five digestion cycles. For the first time it was shown that the digestion process was disturbed in the short term by the presence of the materials that increased the pH of the liquid phase and slowed the acids consumption, with much more impact of the MKAA. However, the final total production of biogas was similar in all bioreactors. Material analyses showed that, in this moderately aggressive medium, the biodeterioration of the CEM I and CEM III pastes mainly led to cement matrix leaching (decalcification) and carbonation. MKAA showed a good behaviour with very low degraded depths. In addition, the material was found to have interesting ammonium adsorption properties in the chemical conditions (notably the pH range) of anaerobic digestion.

The Midgut Ultrastructure of the Sand Fly Vector, Phlebotomus Langeroni (Diptera: Psychodidae)

The midgut ultrastructure of Phlebotomus langeroni, the vector of visceral leismaniasis was studied by the transmission electron microscope. The midgut region warrants a special investigation since it is directly relevant to the development of Leishmania promastigotes. Observations performed on females at time-intervals following a bloodmeal were analyzed and compared. The epithelium of the midgut consisted of a single layer of columner cells surrounded by the basal lamina. Under which there is a musculature consisted of circular and longitudinal fibers. The cells were characterized by large nuclei, densely packed microvilli, and intricate basal labyrinth. The cytoplasm was filled with numerous mitochondria. Morphological changes occurred in the cellular structures during the blood digestion process. The peritrophic matrix was present up to 3 days after the bloodmeal and completely disintegrated at day 4 after bloodmeal. At day 6 after bloodmeal, lipid inclusions were few within the cell cytoplasm and vacuoles were depicted. At day 8, the area of the microvilli was greatly reduced probably due to reduced functional activity along with the end of the digestive cycle. The changes depicted in the midgut of P. langeroni during the process of blood digestion were comparable to those described for other hematophagous dipterans.

A multiple signal amplification electrochemical biosensors based on target DNA recycling for detection of the EGFR mutation status in lung cancer patients

In this study, we construct a multiple amplification biosensor combining a hybridization–digestion cycles in a homogeneous reaction in liquid phase, and a modified streptavidin-biotin complex (SABC) method. To reduce the number of DNA types participating in the hybridization–digestion cycles, we design a dual-functional reporter probe with biotin and -PO4 in both distal ends, which can not only hybridize with the target DNA and be recognized by λ-exo but also bind to streptavidin. The target DNA hybridized with the reporter probe, and then the reporter sequence was digested by λ-exo to release the target DNA. After the hybridization–digestion cycles, the remaining reporter probe was captured by the probe mobilized on the gold electrode. Meanwhile, in modified SABC method, we mixed streptavidin-horseradish peroxidase (SA-HRP) and biotin-HRP to form complexes, which bind to biotin on reporter probe to accumulate large amounts of HRP on the electrode, current was further increased on the basis of the HRP-catalyzed reaction. By the combination of this two signal amplification protocols, the detection limit of this biosensor was 1 pM. Wild-type EGFR in clinical samples from lung cancer patients can be successfully discriminated from EGFR mutations by the proposed method. Our research would make the electrochemical biosensor be an excellent candidate for EGFR status detection in clinical diagnosis and prognosis.

The Life-Cycle Environmental Impact of Recycling of Restaurant Food Waste in Lanzhou, China

The recycling of restaurant food waste can bring environmental benefits and improve food safety for urban residents. We here assessed the entire life cycle of the anaerobic digestion–aerobic composting technique of restaurant food waste recycling using Lanzhou as a case study. We used the CML2001 method provided with the Gabi software and compared the results to those produced using the traditional treatment techniques (landfill and incineration). This work includes a sensitivity analysis of the results. It is here concluded that the anaerobic digestion–aerobic composting technique had the smallest environmental impact of the methods here examined. The life cycle of anaerobic digestion–aerobic composting primarily consumes water, clay, coal, crude oil, and natural gas. The pre-processing phase consumes the most resources, and anaerobic digestion showed the greatest environmental impact. Specific environmental impacts in order from the highest to lowest potential to exacerbate global warming were found to be photochemical ozone production, acidification, eutrophication, marine aquatic ecotoxicity, human toxicity, freshwater aquatic ecotoxicity, and terrestrial ecotoxicity. The main factors associated with different environmental impacts and the environmental impacts themselves were found to differ across different phases. Some environmental impacts were shown to be sensitive to electricity, and the eutrophication potential and photochemical ozone creation potential showed the least sensitivity to all variables. To reduce the environmental impact of the anaerobic digestion–aerobic composting treatment technique, the energy structure and consumption of electricity, water, and diesel need to be optimized.