Betalains are health-promoting plant pigments accumulated in non-anthocyanic plants. Owing to its limited distribution in nature, metabolic trade-offs of inhibiting them are poorly understood. The ...aim of this study was to investigate the effects of inhibition of betalains in
Amaranthus tricolor
seedlings to gain insights into the relationship of betalain biosynthesis with other biosynthetic pathways in betalain-accumulating plants. Phenylalanine (Phe; 12.5, 25, and 50 mmol L
−1
) and 3-methyl-2-benzothiazolinone hydrazone (MBTH) (25 mmol L
−1
) were treated to inhibit betalain biosynthesis in ten-day-old
A. tricolor
(red) seedlings. After two and six days of treatment, target (betalain-related metabolites) and non-target metabolites were analyzed. In two days, Phe content increased by 2.6, 8.5, and 17.4-fold in Phe (12.5, 25, and 50 mmol L
−1
)-treated seedlings, respectively, compared to control, indicating the uptake of Phe by the seedlings. Phe treatment led to a 10.1–18% decrease in betacyanins, while MBTH caused an 18.3% decrease in two days. In both treatments,
cyclo
-DOPA formation, which is essential for betacyanin biosynthesis, seems to be inhibited, albeit through different mechanisms. Betalain biosynthetic precursors and intermediates, viz., tyrosine, L-DOPA, and dopamine decreased differentially. Ascorbic acid,
α
-tocopherol, and retinol contents increased in both treatments concomitant with the reduction in betalains, total phenols, and antioxidant enzymes. Therefore, Phe treatment is beneficial in enhancing antioxidant metabolites in betalain-accumulating plants. However, the mechanism of increasing ascorbic acid on inhibiting betalains needs further investigation in other betalain-producing plants also to understand if ascorbic acid is involved in regulating betalain biosynthesis.
In this work, an analytical model is developed for DM-DG-TMD-FET- based Biosensor including Fringing-field effects. The Analytical model has been developed for two different Device structures, namely ...Device structure-1 (without a gate above the nano-cavity) and Device structure-2 (with a gate above the nano-cavity) based on modulation of the dielectric constant of biomolecules in the nano-cavity region. The proposed model has been validated against both numerical quantum simulation results with the help of a few fitting parameters and it also agrees with the 2-dimensional numeric simulator SILVACO TCAD used in this work. The presence/absence of biomolecules has been detected by the metric of threshold voltage sensitivity Formula: see text and drain current Formula: see text for the neutral as well as charged biomolecules. Sensitivities of partially filled nano-cavities arising out of steric hindrance in both the biosensors are compared. Optimization of device dimensions has also been included in this work to enhance the sensitivity of the biosensors. It has been witnessed that the sensitivity of the proposed biosensor is Formula: see text 100% higher in Device structure-1 for neutral biomolecules with dielectric constant Formula: see text = 12, when compared to Device structure-2 for fully filled cavities. Whereas for the charged biomolecules, Device structure-1 shows Formula: see text 50% enhanced sensitivity than Device structure-2 for Formula: see text Formula: see text. Device structure-1 demonstrates Formula: see text120% higher sensitivity than Device structure-2 with partially filled cavities (i.e. 66% filled cavity). Finally, benchmarking of the proposed biosensor is presented with contemporary, state-of-the-art biosensors and it is highlighted that Formula: see text FET-based biosensor emerges with a superior sensitivity of Formula: see text = 0.81 V for Formula: see text.
In this work, the impact of gate material work function on the sensitivity of dual-material, double-gate, junctionless MOSFET (
D
M
D
G
-
J
L
-
M
O
S
F
E
T
)-based biosensor has been studied. To ...enhance the sensitivity of the biosensor, optimization of gate work functions has been done through Sentaurus TCAD simulator. With the immobilization of biomolecules in the cavity at different value of work function of gate metal 1 (
M
1) and gate metal 2 (
M
2), i.e.,
WF
1 and
WF
2, enhancement in sensing metrics (change in threshold voltage
S
V
th
and
I
ON
/
I
OFF
ratio) is observed. The enhancement in sensitivity is profound in source-side gate (M1) work function (WF1) optimization as compared to drain-side gate (M2) work function (WF2) optimization. Sensitivity of 90 mV is observed in source-side gate work function optimization which is
∼
89% more than the sensitivity of 23 mV which is achieved in drain-side gate work function optimization for a fixed concentration and dielectric constant of biomolecules. It has also been noted that the proposed structure exhibits
∼
90
%
higher sensitivity than the single-material, dual-gate, junctionless MOSFET (
S
M
D
G
-
J
L
-
M
O
S
F
E
T
) biosensor. Results showcase that the optimization of gate metal work functions enhances the sensitivity of the biosensor.
Enhanced permeability of biomembranes upon the application of small amphiphiles is of vital importance to biologists and pharmacists, as their physiochemical interactions open new pathways for ...transdermal drug transportation and administration. Amphiphilic dimethyl sulfoxide (DMSO) is known to alter biomembrane permeability. Atomistic simulation-based studies to explore the impact of amphiphilic molecules on the model lipid membranes are of immense importance. These studies provide molecular details on how the membrane physical properties, such as fluidity and thickness, are modulated by amphiphile-lipid interactions. However, such approaches are usually limited to short simulation time and length scales. To circumvent such limitations, the use of coarse-grained (CG) models is a current computational strategy. In this article, we have presented a new CG force-field for DMSO for molecular dynamics (MD) simulations. The model is designed to reproduce experimental bulk properties of DMSO and its aqueous mixtures, molecular-level structure of liquid DMSO, and the phase transfer energy of a single DMSO molecule from the aqueous phase to the lipid bilayer hydrophobic interior. The current CG DMSO model successfully mimics the structural variation in phospholipid bilayer systems (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine) including alteration in bilayer thickness, lipid tail ordering, lipid lateral packing, and electron density profiles at various DMSO concentrations when compared to those obtained from parallel atomistic simulations.
DNA strand consisting of multiple runs of guanines can adopt the non-canonical, four-stranded DNA secondary structure known as G-quadruplex or G4 DNA. G4 DNA is thought to play an important role in ...transcriptional and translational regulation of genes, DNA replication, genome stability, and oncogene expression in eukaryotic genomes. In other organisms including several bacterial pathogens and some plant species, the biological role of G4 DNA and G4 RNA is starting to be explored. Recent investigation showed that G4 DNA and G4 RNA are generally conserved across plant species.
analyses of several bacterial genomes identified the putative guanine-rich, G4 DNA-forming sequences in the promoter regions. They were particularly abundant in certain gene classes, suggesting that these highly diverse structures can be employed to regulate expression of genes involved in secondary metabolite synthesis and signal transduction. Furthermore, in the pathogen
, the distribution of G4 motifs and their potential role in the regulation of gene transcription advocate for the use of G4 ligands to develop novel antitubercular therapies. In this review, we discuss the various roles of G4 structures in bacterial DNA and the application of G4 DNA as an inhibitor or therapeutic agent to tackle the bacterial pathogens.
SUMMARY
Iron (Fe) is an essential micronutrient for both plants and animals. Fe‐limitation significantly reduces crop yield and adversely impacts on human nutrition. Owing to limited bioavailability ...of Fe in soil, plants have adapted different strategies that not only regulate Fe‐uptake and homeostasis but also bring modifications in root system architecture to enhance survival. Understanding the molecular mechanism underlying the root growth responses will have critical implications for plant breeding. Fe‐uptake is regulated by a cascade of basic helix–loop–helix (bHLH) transcription factors (TFs) in plants. In this study, we report that HY5 (Elongated Hypocotyl 5), a member of the basic leucine zipper (bZIP) family of TFs, plays an important role in the Fe‐deficiency signaling pathway in Arabidopsis thaliana. The hy5 mutant failed to mount optimum Fe‐deficiency responses, and displayed root growth defects under Fe‐limitation. Our analysis revealed that the induction of the genes involved in Fe‐uptake pathway (FIT‐FER‐LIKE IRON DEFICIENCY‐INDUCED TRANSCRIPTION FACTOR, FRO2‐FERRIC REDUCTION OXIDASE 2 and IRT1‐IRON‐REGULATED TRANSPORTER1) is reduced in the hy5 mutant as compared with the wild‐type plants under Fe‐deficiency. Moreover, we also found that the expression of coumarin biosynthesis genes is affected in the hy5 mutant under Fe‐deficiency. Our results also showed that HY5 negatively regulates BRUTUS (BTS) and POPEYE (PYE). Chromatin immunoprecipitation followed by quantitative polymerase chain reaction revealed direct binding of HY5 to the promoters of BTS, FRO2 and PYE. Altogether, our results showed that HY5 plays an important role in the regulation of Fe‐deficiency responses in Arabidopsis.
Significance Statement
The WHO considers iron‐deficiency anemia the most prevalent nutritional deficiency, affecting ~30% of the world's population. The majority of people obtain iron primarily from plants. Despite significant progress in understanding how plants acquire iron from the rhizosphere and transport it within plants, we still lack the complete understanding of how plants sense and respond to iron limitation. Here, we identify a novel role of HY5 (Elongated Hypocotyl 5), a member of the basic leucine zipper (bZIP) transcription factors family under Fe‐limitation conditions. We provide novel evidence that HY5 regulation of BTS (an iron‐binding E3 ligase) is critical for the Fe‐deficiency responses in Arabidopsis. This study improves our knowledge about plant response to Fe‐deficiency as well as adds a new role in the repertoire of HY5‐mediated pathways.
Multi-walled carbon nanotubes (MWCNTs) with special nanoneedle structure have emerged as new promising candidates for plasmid and drug delivery. However, the delivery is greatly limited by the high ...tendency of CNT to form aggregates, the “less dispersion problem,” and CNT cytotoxicity. Here, we described an extensive evaluation of the ability of layer-by-layer modification strategy to reduce CNT size and toxicity, and to shield CNT hydrophobic surfaces. The MWCNTs can be derivatized with carboxylate groups (cMWCNT) and sequentially functionalized with protein, cationic polyethylenimine (PEI), and polysaccharide. The protein coating, characterized by Fourier transform infrared and deconvolution methods, could serve as the hydrophilic, biocompatible matrix and scaffold for sequential conjugation. We found that coated PEI-enhanced electrostatic interactions between plasmid DNA and CNTs. The functionalized cMWCNTs were analyzed by thermogravimetric analysis, dynamic light scattering, and electron microscopy technologies. The conjugation of cMWCNTs–ovalbumin–PEI with oxidized pectin further promoted green fluorescence intensity by balancing the intracellular DNA release and were easier to disperse. Our in-depth study demonstrated that functionalized CNTs can be improved by fine-tuned process parameters of the protein–PEI–polysaccharide modification.
Group B Streptococcus (GBS) is a causative agent of various infections in newborns, immunocompromised (especially diabetic) non-pregnant adults, and pregnant women. Antibiotic resistance profiling ...can provide insights into the use of antibiotic prophylaxis against potential GBS infections. Virulence factors are responsible for host-bacteria interactions, pathogenesis, and biofilm development strategies. The aim of this study was to determine the biofilm formation capacity, presence of virulence genes, and antibiotic susceptibility patterns of clinical GBS isolates.
The resistance rate was highest for penicillin (27%; n = 8 strains) among all the tested antibiotics, which indicates the emergence of penicillin resistance among GBS strains. The susceptibility rate was highest for ofloxacin (93%; n = 28), followed by azithromycin (90%; n = 27). Most GBS strains (70%; n = 21) were strong biofilm producers and the rest (30%; n = 9) were moderate biofilm producers. The most common virulence genes were cylE (97%), pavA (97%), cfb (93%), and lmb (90%). There was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility, according to Spearman's rank correlation analysis.
About a third of GBS strains exhibited penicillin resistance and there was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility. Further, both the strong and moderate biofilm producers carried most of the virulence genes tested for, and the strong biofilm formation phenotype was not associated with the presence of any virulence genes.
This paper reports study of Raman and Photoluminescence (PL) characteristics of ZnTe crystal excited by near band-edge laser. The Raman spectra exhibited strong longitudinal-optical (LO) multiphonon ...peaks due to onset of resonance phenomenon. The optical excitation power response showed increase in the Raman multiphonon peak intensity with laser power with no shift in peak positions. The PL spectra also exhibited similar effect with the near band-edge peak intensity increasing with laser power without any peak shift. Increasing the temperature from 80 to 300 K showed a decrease in the multiphonon peak intensity. The Raman spectra at different sample temperatures are dominated by strong LO multiphonon peaks; however, a transverse optical (TO) Raman peak was also observed in the Raman spectra at temperature of 173 K and below indicating a shift from resonance (at room temperature and down to 173 K) to non-resonance condition (below 173 K). In addition, strong electron–phonon coupling is observed in the bulk ZnTe single crystal substantiated by high values of Huang–Rhys parameter in the considered temperature range. Within the band-edge resolvable temperature range (300–223 K), the near band-edge luminescence intensity also increased with decrease in the sample temperature along with a blue shift in the peak position.
Factors controlling organic carbon stabilization are elusive in neutral-to-alkaline soils, thereby hindering the assessment of carbon sequestration potential across vast agricultural regions like the ...Indo-Gangetic Plain (IGP). This study investigated controls over mineralization and stabilization of added organic matter in tropical neutral-to-alkaline soils with low organic carbon (SOC). Using topsoil and subsoil samples from 12 sites of upper-to-lower IGP, we conducted a one-year incubation with and without adding 13C-labeled maize material. We tracked CO2 release and residual C remaining in soil organic matter fractions (free, occluded particulate (oPOM), and mineral-associated organic matter (MAOM)) and analyzed organic matter molecular compositions in incubated soils using pyrolysis-GC/MS. Our results revealed that 48 ± 7 % of added maize C was mineralized, mostly within the first 70 days. Higher active Al/Fe, notably Al, retarded primary maize mineralization by facilitating aggregation. High SOC content and SOC saturation degree resulted in more maize mineralization. The disappearance of maize-unique compounds (e.g., neophytadiene) revealed substantial degradation of added maize. Regarding SOC composition, maize addition increased the relative abundance of fatty acids and decreased that of N-containing compounds. Most residual maize-derived C was found in stabilized fractions, MAOM (77 ± 15 % of residual maize C) and oPOM (8 ± 4 %). Clay fraction contributed to most maize-derived C stabilization as MAOM (path coefficient (β) = 0.81**). Moreover, the significant correlation (P < 0.001) between maize-derived oPOM C and active Al/Fe or clay + silt suggested that active Al/Fe contributed to the stabilization of maize-derived C as oPOM (β = 0.62***) probably by bonding clay and silt particles to form stable aggregates since active Al/Fe content was low (<14 cmol kg−1). Our study highlighted the importance of active Al/Fe in stabilizing SOC, by promoting aggregation and retarding degradation of residue-derived C in neutral-to-alkaline soils.
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