Spectroscopic Identification of Charge Transfer of Thiolated Molecules on Gold Nanoparticles via Gold Nanoclusters.

Investigation of charge transfer needs analytical tools that could reveal this phenomenon, and enables understanding of its effect at the molecular level. Here, we show how the combination of using gold nanoclusters (AuNCs) and different spectroscopic techniques could be employed to investigate the charge transfer of thiolated molecules on gold nanoparticles (AuNP@Mol). It was found that the charge transfer effect in the thiolated molecule could be affected by AuNCs, evidenced by the amplification of surface-enhanced Raman scattering (SERS) signal of the molecule and changes in fluorescence lifetime of AuNCs. Density functional theory (DFT) calculations further revealed that AuNCs could amplify the charge transfer process at the molecular level by pumping electrons to the surface of AuNPs. Finite element method (FEM) simulations also showed that the electromagnetic enhancement mechanism along with chemical enhancement determines the SERS improvement in the thiolated molecule. This study provides a mechanistic insight into the investigation of charge transfer at the molecular level between organic and inorganic compounds, which is of great importance in designing new nanocomposite systems. Additionally, this work demonstrates the potential of SERS as a powerful analytical tool that could be used in nanochemistry, material science, energy, and biomedical fields.

Ferroelectric Domain and Switching Dynamics in Curved In2Se3: First-Principles and Deep Learning Molecular Dynamics Simulations.

Despite its prevalence in experiments, the influence of complex strain on material properties remains understudied due to the lack of effective simulation methods. Here, the effects of bending, rippling, and bubbling on the ferroelectric domains are investigated in an In2Se3 monolayer by density functional theory and deep learning molecular dynamics simulations. Since the ferroelectric switching barrier can be increased (decreased) by tensile (compressive) strain, automatic polarization reversal occurs in α-In2Se3 with a strain gradient when it is subjected to bending, rippling, or bubbling deformations to create localized ferroelectric domains with varying sizes. The switching dynamics depends on the magnitude of curvature and temperature, following an Arrhenius-style relationship. This study not only provides a promising solution for cross-scale studies using deep learning but also reveals the potential to manipulate local polarization in ferroelectric materials through strain engineering.

Reconsideration of maternal serological testing for predicting congenital CMV infection.

BACKGROUND: The value of the widely applied maternal cytomegalovirus (CMV) serological testing approach in predicting intrauterine transmission in highly seroprevalent regions remains unknown. METHODS: A nested case‒control study was conducted based on a maternal-child cohort study. Newborns with congenital CMV (cCMV) infection were included, and each of them was matched to 3 newborns without cCMV infection. Retrospective samples were tested for immunoglobulin G (IgG) avidity and immunoglobulin M (IgM) antibodies in maternal serum and CMV DNA in maternal blood and urine to analyse their associations with cCMV infection. RESULTS: Forty-eight newborns with cCMV infection and 144 matched newborns without infection were included in the study. Maternal IgM antibodies and IgG avidity during pregnancy were not statistically associated with intrauterine transmission. The presence of CMV DNAemia indicated a higher risk of cCMV infection, with the OR values as 5.7, 6.5 and 13.0 in early, middle and late pregnancy, respectively. However, the difference in CMV shedding rates in transmitters and nontransmitters was not significant in urine. CONCLUSION: The value of current maternal CMV serological testing in regions with high seropositivity rates is very limited and should be reconsidered. The detection of DNAemia would be helpful in assessing the risk of intrauterine transmission.

Analysis of the chloroplast crotonylome of wheat seedling leaves reveals the roles of crotonylated proteins involved in salt-stress responses.

Lysine crotonylation (Kcr) is a novel post-translational modification and its function in plant salt-stress responses remains unclear. In this study, we performed the first comprehensive chloroplast crotonylome analysis of wheat seedling leaves to examine the potential functions of Kcr proteins in salt-stress responses. In a total of 471 chloroplast proteins, 1290 Kcr sites were identified as significantly regulated by salt stress, and the Kcr proteins were mainly involved in photosynthesis, protein folding, and ATP synthesis. The identified Kcr sites that responded to salt stress were concentrated within KcrK and KcrF motifs, with the conserved KcrF motif being identified in the Kcr proteins of wheat chloroplasts for the first time. Notably, 10 Kcr sites were identified in fructose-1,6-bisphosphate aldolase (TaFBA6), a key chloroplast metabolic enzyme involved in the Calvin-Benson cycle. Site-directed mutagenesis of TaFBA6 showed that the Kcr at K367 is critical in maintaining its enzymatic activity and in conferring salt tolerance in yeast. Further molecular dynamic simulations and analyses of surface electrostatic potential indicated that the Kcr at K367 could improve the structural stability of TaFBA6 by decreasing the distribution of positive charges on the protein surface to resist alkaline environments, thereby promoting both the activity of TaFBA6 and salt tolerance.

MicroSugar: A database of comprehensive miRNA target prediction framework for sugarcane (Saccharum officinarum L.).

microRNA (miRNA) is a group of small non-coding RNA that plays important role in post-transcription of gene expression. With the studies about miRNA increase in sugarcane, the researchers lack an exhaustive resource to achieve the data. To fill this gap, we developed MicroSugar, a database that supported mRNA and miRNA annotation for sugarcane (http://suc.gene-db.com). MicroSugar is an integrated resource developed for 194,528 genes including 80,746 unigenes from long reads of Pacbio platform and 468 miRNAs from 72 samples. Internode elongation (jointing) is the key biological characteristic for the growth of sugarcane tillers into sugarcane stems. The present study combined the sequencing data from the different stages in internode elongation of stem and tiller. In total, the 14,300 3' untranslated region (UTR) sequences were extracted from the gene sequences and 3019 mRNAs as target of 327 miRNA were identified by miRanda algorithm and Spearman's Rho of expression levels. To determine the gene functions regulated by these miRNAs, the gene ontology enrichment analysis was performed and it confirmed that the over-represented Gene Ontology (GO) terms were associated with organism formation indicating the growth controlling function by miRNAs in sugarcane. Moreover, MicroSugar is a comprehensive and integrated database with a user-friendly responsive template. By browsing, searching and downloading of the nucleotide sequences, expression and miRNA targets, the user can retrieve information promptly. The database provides a valuable resource to facilitate the understanding of miRNA in sugarcane development and growth which will contribute to the study of sugarcane and other plants.

A Self-Made Optical Tweezers Integrated Upconversion Luminescence Confocal Scanning Instrument Enables Stable and Noninvasive Long-Term In Situ Imaging a Single Suspension Cell Under Exceptionally Efficient Luminescent Resonance Energy Transfer Sensing.

It is necessary to explore labeling probes with worthy optical properties and a noninvasive fluorescence imaging manner for stable long-term in situ measuring a single suspension cell. In response to these goals, we herein make a breakthrough on two fronts. On one hand, a co-sensitizer-induced efficient 808 nm near-infrared light-excited luminescence-confined upconversion nanoparticle with a low thermal effect is fabricated by employing a layer-by-layer seed growing approach to develop a sandwich structure, under which the luminescence domain is vastly restricted into an extremely thin inner shell (∼ 2.77 nm) to finally bring about a high-efficiency luminescent resonance energy transfer (LRET) sensing behavior. On the other hand, a self-made optical tweezers integrated upconversion luminescence confocal scanning instrument is applied to enhance the imaging accuracy, after which the liquid viscous force is sufficiently overcome by the resulting single beam gradient force and the analyzed suspension cell is always immobilized to the focal plane to ensure a constant luminescence excitation condition. By making use of a metal ion-dependent DNAzyme and a hairpin DNA strand to design a corresponding LRET sensing system, our nanoprobe shows satisfactory assay performance for two model biomolecules (Ca2+ and TK1 messenger RNA). Following the optical trapping-assisted imaging, this exceptional measurement method is capable of effectively monitoring the intracellular target changes in different physiological states, endowing a powerful toolbox for single cell analysis.

Upconversion Luminescence-Initiated and GSH-Responsive Self-Driven DNA Motor for Automatic Operation in Living Cells and In Vivo.

In light of the worthy design flexibility and the good signal amplification capacity, the recently developed DNA motor (especially the DNA walker)-based fluorescent biosensors can offer an admirable choice for realizing bioimaging. However, this attractive biosensing strategy not only has the disadvantage of uncontrollable initiation but also usually demands the supplement of exogenous driving forces. To handle the above obstacles, some rewarding solutions are proposed here. First, on the surface of an 808 nm near-infrared light-excited low-heat upconversion nanoparticle, a special ultraviolet upconversion luminescence-initiated three-dimensional (3D) walking behavior is performed by embedding a photocleavage linker into the sensing elements, and such light-controlled target recognition can perfectly overcome the pre-triggering of the biosensor during the biological delivery to significantly boost the sensing precision. After that, a peculiar self-driven walking pattern is constructed by employing MnO2 nanosheets as an additional nanovector to physically absorb the sensing frame, for which the reduction of the widespread glutathione in the biological medium can bring about sufficient self-supplied Mn2+ to guarantee the walking efficiency. By selecting an underlying next-generation broad-spectrum cancer biomarker (survivin messenger RNA) as the model target, we obtain that the newly formed autonomous 3D DNA motor shows a commendable sensitivity (where the limit of detection is down to 0.51 pM) and even an outstanding specificity for distinguishing single-base mismatching. Beyond this sound assay performance, our sensing approach is capable of working as a powerful imaging platform for accurately operating in various living specimens such as cells and bodies, showing a favorable diagnostic ability for cancer care.

Echinochrome A Reverses Kidney Abnormality and Reduces Blood Pressure in a Rat Model of Preeclampsia.

We aimed to observe the effects of Echinochrome A (Ech A) on systemic changes using a rat model of preeclampsia. The results showed that an infusion of angiotensin II (Ang II) through an osmotic pump (1 µg/kg/min) on GD 8 increased systolic and diastolic blood pressures and reduced fetal weight and placental weight. The diameters of the glomeruli were expended and glomeruli capillaries were diminished. No change was observed in the heart and liver in the Ang II group, but epithelial structures were disrupted in the uterus. Ech A treatment on GD 14 (100 µg/µL) through the jugular vein reduced systolic and diastolic blood pressures and reversed glomerulus alterations, but the fetal or placental parameters were unaffected. Ech A only partly reversed the effect on the uterus. The mRNA expression of TNF-α was increased and IL-10 and VEGF were reduced in the uterus of the Ang II group, while Ech A restored these changes. A similar trend was observed in the kidney, liver, and heart of this group. Furthermore, Bcl-2 was reduced and Bcl-2/Bax ratios were significantly reduced in the kidney and heart of the Ang II group, while Ech A reversed these changes. We suggest that Ech A modulates inflammation and apoptosis in key systemic organs in Ang II-induced rat preeclampsia and preserves kidney and uterus structures and reduces blood pressure.

A Photoresponsive and Metal-Organic Framework Encapsulated DNA Tetrahedral Entropy-Driven Amplifier for High-Performance Imaging Intracellular MicroRNA.

The further development of high-performance fluorescent biosensors to image intracellular microRNAs is beneficial to cancer medicine. By virtue of the need for enzymes and hairpin DNA probes, the entropy-driven reaction-assisted signal amplification strategy has shown an enormous potential to accomplish this task. Nevertheless, this good option still meets with poor biostability, low cell uptake efficiency, and unsatisfactory accuracy. On the basis of these challenges, we put forward here a battery of solving pathways. First, the straight DNA probes are anchored onto the vertexes of dual DNA tetrahedrons, and thus the enzyme resistance of the whole sensing system is observably enhanced. A metal-organic framework (ZIF-8 nanoparticle), which can be effectively dissociated into a weakly acidic environment, then is employed as an additional delivery vehicle to encapsulate such a DNA tetrahedron sustained biosensor and finally bring about a more efficient endocytosis. Last, a kind of photocleavage-linker triggered photoresponsive manner is incorporated to achieve an exceptional precise target identification, by which the biosensor can only be initiated under the irradiation of an externally mild 365 nm ultraviolet light source. In accordance with the above efforts, worthy assay performance toward microRNA-196a has given rise to this newly constructed biosensor, whose sensitivity is down to 2.7 pM and also able to distinguish single-base variation. Beyond that, the amplifier can work as a powerful imaging toolbox to accurately determine the targets in living cells, providing a promising intracellular sensing platform.

Theoretical understanding of the properties of stepped iron surfaces with van der Waals interaction corrections.

The stepped surfaces in nanoscale zero-valent iron (nZVI) play an essential role for environmental application. However, there is still currently a deficiency in the atomic understanding of stepped surface properties due to the limitation of the computational methodology. In this study, stepped Fe(210) and (211) surfaces were theoretically investigated using density functional theory (DFT) computations in terms of the flat Fe(110) surface. Our results suggest that the consideration of van der Waals (vdW) interaction correction is beneficial for the DFT study on Fe-based systems. The DF-cx method is found to be the most promising vdW correction method. The DF-cx results reveal that the stepped Fe(210) and Fe(211) surfaces experience significant surface relaxation and abnormal trends in their work function. Their electronic properties and reactivities of the surface atoms are strongly affected by the Fe coordination numbers and the strong adsorption strengths of oxygen on the surfaces are dependent on both the coordination number of the adsorbed atoms and the geometry of the adsorption sites.

Reinvestigating oxygen adsorption on Ag(111) by using strongly constrained and appropriately normed semi-local density functional with the revised Vydrov van Voorhis van der Waals force correction.

While density functional theory (DFT) at the generalized gradient approximation (GGA) level has made great success in catalysis, it fails in some important systems such as the adsorption of the oxygen molecule on the Ag(111) surface. Previous DFT studies at the GGA level revealed theoretical inconsistencies on the adsorption energies and dissociation barriers of O2 on Ag(111) in comparison with the experimental conclusion. In this study, the strongly constrained and appropriately normed-revised Vydrov van Voorhis van der Waals correction functional (SCAN-rVV10) method at the meta-GGA level with the nonlocal van der Waals (vdW) force correction was used to reinvestigate the adsorption properties of O2 on the Ag(111) surface. The SCAN-rVV10 results successfully confirm the experimental observation that both molecular and dissociative adsorptions can exist for oxygen on Ag(111). The calculated adsorption energy for the physisorption state and the relevant dissociation energy barrier are close to the experimental data. It demonstrates that SCAN-rVV10 can outperform functionals at the GGA level for O2/Ag(111). Therefore, our findings suggest that SCAN-rVV10 can be the desired method for systems where the correct description of intermediate-ranged vdW forces is essential, such as the physisorption of small molecules on the solid surface.

Effects of compositional engineering and surface passivation on the properties of halide perovskites: a theoretical understanding.

Halide perovskite solar cells have demonstrated high power conversion efficiency. Compositional engineering and surface passivation technologies have been drawing great attention to enhance their energy conversion efficiency and moisture resistance. In this study, the density functional theory method was employed to understand the effects of compositional engineering at the A site of perovskites and the 3-butenoic acid-based passivation layer on the structural, electronic and optical properties of halide perovskites. Our results suggest that the electronic and optical properties of CsPbI3 can be tuned by the mixing of caesium and FA cations. Moreover, the calculation of adsorption energies on mixed-cation Cs1-xFAxPbI3(001) surfaces reveals that the much stronger adsorption strength of 3-butenoic acid facilitates blocking of the interaction of surfaces with water molecules. Meanwhile, the calculated results indicate that adopting such an organic molecule as a passivation layer does not compromise their excellent electronic and optical properties. Our theoretical understanding of the A cation engineering and organic molecule-based surface passivation will be beneficial to the improvement of the overall performance of perovskite solar cells.

Integrated mRNA and small RNA sequencing reveals microRNA regulatory network associated with internode elongation in sugarcane (Saccharum officinarum L.).

BACKGROUND: Internode elongation is one of the most important traits in sugarcane because of its relation to crop productivity. Understanding the microRNA (miRNA) and mRNA expression profiles related to sugarcane internode elongation would help develop molecular improvement strategies but they are not yet well-investigated. To identify genes and miRNAs involved in internode elongation, the cDNA and small RNA libraries from the pre-elongation stage (EI), early elongation stage (EII) and rapid elongation stage (EIII) were sequenced and their expression were studied. RESULTS: Based on the sequencing results, 499,495,518 reads and 80,745 unigenes were identified from stem internodes of sugarcane. The comparisons of EI vs. EII, EI vs. EIII, and EII vs. EIII identified 493, 5035 and 3041 differentially expressed genes, respectively. Further analysis revealed that the differentially expressed genes were enriched in the GO terms oxidoreductase activity and tetrapyrrole binding. KEGG pathway annotation showed significant enrichment in "zeatin biosynthesis", "nitrogen metabolism" and "plant hormone signal transduction", which might be participating in internode elongation. miRNA identification showed 241 known miRNAs and 245 novel candidate miRNAs. By pairwise comparison, 11, 42 and 26 differentially expressed miRNAs were identified from EI and EII, EI and EIII, and EII and EIII comparisons, respectively. The target prediction revealed that the genes involved in "zeatin biosynthesis", "nitrogen metabolism" and "plant hormone signal transduction" pathways are targets of the miRNAs. We found that the known miRNAs miR2592-y, miR1520-x, miR390-x, miR5658-x, miR6169-x and miR8154-x were likely regulators of genes with internode elongation in sugarcane. CONCLUSIONS: The results of this study provided a global view of mRNA and miRNA regulation during sugarcane internode elongation. A genetic network of miRNA-mRNA was identified with miRNA-mediated gene expression as a mechanism in sugarcane internode elongation. Such evidence will be valuable for further investigations of the molecular regulatory mechanisms underpinning sugarcane growth and development.

Single-cell analysis reveals the effects of glutaraldehyde and formaldehyde on individual Nosema bombycis spores.

Nosema bombycis (Nb) is the pathogen that causes pebrine in silkworms. Aldehydes are effective disinfectants commonly used in sericulture. However, the precise mechanism of their action on Nb spores remains unclear. Here, we used laser tweezers Raman spectroscopy to investigate the effects of glutaraldehyde and formaldehyde on individual Nb spores, as well as phase contrast microscopy imaging to monitor the germination dynamics of individual treated spores, to acquire a deeper understanding of the mechanism of action of aldehydes and to provide a theoretical reference for establishing an effective strategy for disease control in sericulture. The positions of the Raman peaks remained constant during treatment. The Raman intensity was enhanced and the germination rate of the spores significantly decreased with treatment time. Tlag, the time when individual spores begin to germinate, and Tgerm, the time for complete germination, increased with enhanced treatment. The germination time (ΔTgerm) showed no significant difference from that for untreated spores. Heterogeneity was shown, which is relevant to the resistance of Nb spores to aldehydes. The results indicate that glutaraldehyde and formaldehyde do not destroy the spore wall and plasma membrane, do not cause the leakage of intracellular components, and might not damage the extrusion apparatus. The effects of aldehydes on Nb spores are mainly on the spore coat. They may block the external factors that stimulate spore germination. Single-cell analysis based on novel optical techniques reveals the action of chemical sporicides on microsporidia spores in real time and explains the heterogeneity of cell stress resistance. These applications of new techniques offer new insight into traditional disinfectants.

Enhanced Activity and Selectivity for Nitrogen Reduction Reaction in Electrides-Based Heterostructures: A DFT Computational Study.

Developing sustainable and efficient catalysts for ammonia synthesis from atmospheric molecular N2 under ambient conditions presents a significant 21st-century challenge. Two-dimensional heterostructures, particularly single-atom catalysts (SACs) supported on two-dimensional materials, have emerged as a promising avenue due to their remarkable catalytic activity and selectivity. Electrides, characterized by an abundance of free electrons and high surface activity, have attracted substantial attention in this context. Through density functional theory (DFT) calculations, this study proposes electride-graphene heterostructures (EGHS) as catalysts to effectively regulate charge distribution at the catalytic center, facilitating the optimization of catalytic performance. The EGHS model addresses challenges related to excessive adsorbate binding, mitigating electron transfer compared to electride monolayer adsorption. This novel approach utilizes heterogeneous heterostructures to finely tune the catalytic site, optimizing electron input for enhanced catalysis. Based on the optimized charge transfer for N2 activation, the Cr-doped EGHS (Cr@EGHS) exhibits a promising performance in the nitrogen reduction reaction, leading to, a relatively low limiting potential of -0.85 V and high selectivity. The hypothesis charge transfer depend on N2 activation is further supported by modulating the distance between component layers of heterostructure. These findings contribute to design principles for 2D heterostructure catalysts and offer a reference for experimental synthesis.

The Characteristics of the Root-Zone Soil's Biological Properties and Microbial Community Structure in Grafted Star Anise Plantations.

Extensive management seriously affects the output, quality, and sustainable development of star anise, and grafting is commonly used to improve its production and quality. Although many studies have explored the effects of grafting on soil microorganisms for other plants, there is a lack of research on aromatic plants, especially on the soil ecosystems of star anise plantations. The effect of grafting star anise on the soil's biological characteristics and microbial composition remains unclear. The soil's enzyme activities, soil microbial biomass, and microbial community composition in grafted and non-grafted star anise plantations in Guangxi, China were studied using high-throughput sequencing technology. The results showed that the microbial biomass carbon and phosphorus contents in the soils of grafted star anise were significantly lower and the phosphatase activity was significantly higher than in the soils of non-grafted star anise. In comparison with the soils of non-grafted star anise plantations, the proportions of Proteobacteria, Acidobacteria, Actinobacteria, and WPS-2 decreased and the proportions of Chloroflexi, Planctomycetes, and Verrucomicrobia increased in the grafted star anise plantations. Meanwhile, Bacteroidetes was a dominant bacterial phylum unique to the soil of the grafted star anise plantations. Moreover, the proportions of Ascomycota and Basidiomycota increased and the proportions of Mortierellomycota and unclassified_k_Fungi decreased in the soils of the grafted star anise plantations. Furthermore, Basidiomycota and Rozellomycota had significant dominance in the grafted star anise plantations. In general, grafting can improve soil fertility and maintain soil health by promoting soil nutrient cycling and increasing the soil's microbial diversity.

Design of a recombinant asparaginyl ligase for site-specific modification using efficient recognition and nucleophile motifs.

Asparaginyl ligases have been extensively utilized as valuable tools for site-specific bioconjugation or surface-modification. However, the application is hindered by the laborious and poorly reproducible preparation processes, unstable activity and ambiguous substrate requirements. To address these limitations, this study employed a structure-based rational approach to obtain a high-yield and high-activity protein ligase called OaAEP1-C247A-aa55-351. It was observed that OaAEP1-C247A-aa55-351 exhibits appreciable catalytic activities across a wide pH range, and the addition of the Fe3+ metal ion effectively enhances the catalytic power. Importantly, this study provides insight into the recognition and nucleophile peptide profiles of OaAEP1-C247A-aa55-351. The ligase demonstrates a higher recognition ability for the "Asn-Ala-Leu" motif and an N-terminus "Arg-Leu" as nucleophiles, which significantly increases the reaction yield. Consequently, the catalytic activity of OaAEP1-C247A-aa55-351 with highly efficient recognition and nucleophile motif, "Asn-Ala-Leu" and "Arg-Leu" under the buffer containing Fe3+ is 70-fold and 2-fold higher than previously reported OaAEP1-C247A and the most efficient butelase-1, respectively. Thus, the designed OaAEP1-C247A-aa55-351, with its highly efficient recognition and alternative nucleophile options, holds promising potential for applications in protein engineering, chemo-enzymatic modification, and the development of drugs.

Molecular profiling of genetic variability in domesticated groundnut (Arachis hypogaea L.) based on ISJ, URP, and DAMD markers.

To detect DNA polymorphisms in the peanut, we screened 26 polymorphic primers using intron-exon splice junction (ISJ), universal rice primer (URP), and directed amplification of minisatellite region DNA (DAMD) techniques. Amplification of genomic DNA of 16 peanut accessions yielded 121 ISJ, 50 URP, and 25 DAMD fragments, of which 34, 25 and 16 were polymorphic, respectively. The range of polymorphism was 10.0-62.5%, averaging 27.7%, for ISJ; 20-80%, averaging 49.5%, for URP; and 28.6-50.0%, averaging 36.3%, for DAMD. In comparisons of multiplex ratio, average polymorphism information content, and marker index, the URP markers were relatively more efficient than ISJ and DAMD markers. Clustering results remained more or less the same with ISJ and URP markers. To the best of our knowledge, this is the first report on the study of the genetic diversity of the peanut using ISJ, URP, and DAMD markers.

Research on microbial lipid production from potato starch wastewater as culture medium by Lipomyces starkeyi.

In this paper, potato starch wastewater as culture medium was treated by the oleaginous yeast Lipomyces starkeyi to biosynthesize microbial lipid. The result indicated that carbon source types, carbon source concentration, nitrogen source types, nitrogen source concentration, inoculum size, and cultivation time all had a significant effect on cell growth and microbial lipid accumulation in batch cultures. A measure of 120 g/L of glucose concentration, 3.0 g/L of (NH4)2SO4 concentration, 10% inoculum size, and incubation time 96 h cultivated in a shaking flask at 30 °C were found to be the optimal conditions not only for cell growth but also for lipid synthesis. Under this condition, the cellular biomass and lipid content could reach 2.59 g/L and 8.88%, respectively. This work provides a new method for effective utilization of potato starch wastewater, which has particular social and economic benefits for yeast treatment technology.

[Baseline correction of Raman spectrum based on piecewise linear fitting].

The baseline drifts of Raman spectra occur in many types of instrumental measurements. It is an important part and a routine step to correct the baseline drift for the data preprocessing. In the present work, the limitations of the baseline correction method based on polynomial fitting were highlighted and a modified polynomial fitting method, i. e. piecewise linear fitting method, was proposed. Combined with the computer, this method could eliminate the baseline automatically. A series of Raman spectra of single polystyrene bead, red blood cell or yeast cell acquired by laser tweezers Raman spectroscopy were preprocessed by this method and its efficiency was verified. The results demonstrated that piecewise linear fitting can correct the baseline shifts effectively and provides more accurate information for further data analysis. It is a feasible method for correction of Raman spectrum.