Observations of rapidly growing whistler waves in front of space plasma shock

Whistler mode wave is a fundamental perturbation of electromagnetic fields and plasmas in various environments including planetary space, laboratory and astrophysics. The origin and evolution of the waves are a long-standing question due to the limited instrumental capability in resolving highly variable plasma and electromagnetic fields. Here, we analyse data with the high time resolution from the multi-scale magnetospheric spacecraft in the weak magnetic environment (i.e., foreshock) enabling a relatively long gyro-period of whistler mode wave. Moreover, we develop a novel approach to separate the three-dimensional fluctuating electron velocity distributions from their background, and have successfully captured the coherent resonance between electrons and electromagnetic fields at high frequency, providing the resultant growth rate of unstable whistler waves. Regarding the energy origin for the waves, the ion distributions are found to also play crucial roles in determining the eigenmode disturbances of fields and electrons. The quantification of wave growth rate can significantly advance the understandings of the wave evolution and the energy conversion with particles

Significance of Cuscutain, a cysteine protease from Cuscuta reflexa, in host-parasite interactions

<p>Abstract</p> <p>Background</p> <p>Plant infestation with parasitic weeds like <it>Cuscuta reflexa </it>induces morphological as well as biochemical changes in the host and the parasite. These modifications could be caused by a change in protein or gene activity. Using a comparative macroarray approach <it>Cuscuta </it>genes specifically upregulated at the host attachment site were identified.</p> <p>Results</p> <p>One of the infestation specific <it>Cuscuta </it>genes encodes a cysteine protease. The protein and its intrinsic inhibitory peptide were heterologously expressed, purified and biochemically characterized. The haustoria specific enzyme was named cuscutain in accordance with similar proteins from other plants, e.g. papaya. The role of cuscutain and its inhibitor during the host parasite interaction was studied by external application of an inhibitor suspension, which induced a significant reduction of successful infection events.</p> <p>Conclusions</p> <p>The study provides new information about molecular events during the parasitic plant - host interaction. Inhibition of cuscutain cysteine proteinase could provide means for antagonizing parasitic plants.</p

An all-silicon design of a high-efficiency broadband transmissive terahertz polarization convertor

Abstract Polarization, a fundamental behavior of electromagnetic waves, holds immense potential across diverse domains such as environmental monitoring, biomedicine, and ocean exploration. However, achieving efficient modulation of terahertz waves with wide operational bandwidth poses significant challenges. Here, we introduce an all-silicon polarization converter designed specifically to operate in the terahertz range of the electromagnetic spectrum. Simulation results demonstrate that the average conversion efficiency of cross-linear waves exceeds 80% across a wide frequency range spanning from 1.00 to 2.32 THz, with the highest conversion efficiency peaking at an impressive 99.97%. Additionally, our proposed structure facilitates linear-to-circular polarization conversion with an ellipticity of 1 at 0.85 THz. Furthermore, by rotating the cross-shaped microstructure, active control over arbitrary polarization states can be achieved. To summarize, the proposed structure offers remarkable flexibility and ease of integration, providing a reliable and practical solution for achieving broadband and efficient polarization conversion of terahertz waves. Graphical abstrac

Interaction of GB1 with Metal Ions Studied by NMR Spectroscopy

B1 domain of staphylococcal protein G (GB1) is a widely used model protein for developing in vivo and in vitro protein structural determination methods based on paramagnetic nuclear magnetic resonance (NMR) such as pseudocontact chemical shift (PCS) and paramagnetic relaxation enhancement (PRE). However, few previous studies have investigated the interactions between GB1 and metal ions, especially paramagnetic ions. In this study, the interactions between GB1 and divalent/lanthanide metal ions were studied by NMR spectroscopy. It was found that GB1 weakly bound with paramagnetic lanthanide ions and paramagnetic divalent ions, including Cu2+, Mn2+ and Co2+. In contrast, GB1 did not bind with diamagnetic divalent ions, such as Ca2+, Mg2+ and Zn2+. Furthermore, it was demonstrated that there were two binding sites for Cu2+ in GB1, but only one for lanthanide ions and divalent ions Mn2+ and Co2+. The current study demonstrated that NMR spectroscopy is a powerful tool to study weak binding between protein and metal ions. And the results indicated that care must be taken to avoid possible interference to paramagnetic NMR data when using GB1 as the model protein

RETRACTED ARTICLE: Substrates specificity of tannase from Streptomyces sviceus and Lactobacillus plantarum

Abstract Tannases can catalyze the hydrolysis of galloyl ester and depside bonds of hydrolysable tannins to release gallic acid and glucose, but tannases from different species have different substrate specificities. Our prior studies found that tannase from Lactobacillus plantarum (LP-tan) performed a higher esterase activity, while the tannase from Streptomyces sviceus (SS-tan) performed a higher depsidase activity; but the molecular mechanism is not elucidated. Based on the crystal structure of LP-tan and the amino acid sequences alignment between LP-tan and SS-tan, we found that the sandwich structure formed by Ile206-substrate-Pro356 in LP-tan was replaced with Ile253-substrate-Gly384 in SS-tan, and the flap domain (amino acids: 225–247) formed in LP-tan was missed in SS-tan, while a flap-like domain (amino acids: 93–143) was found in SS-tan. In this study, we investigated the functional role of sandwich structure and the flap (flap-like) domain in the substrate specificity of tannase. Site-directed mutagenesis was used to disrupt the sandwich structure in LP-tan (P356G) and rebuilt it in SS-tan (G384P). The flap in LP-tan and the flap-like domain in SS-tan were deleted to construct the new variants. The activity assay results showed that the sandwich and the flap domain can help to catalytic the ester bonds, while the flap-like domain in SS-tan mainly worked on the depside bonds. Enzymatic characterization and kinetics data showed that the sandwich and the flap domain can help to catalytic the ester bonds, while the flap-like domain in SS-tan may worked on the depside bonds

Retraction Note to: Substrates specificity of tannase from Streptomyces sviceus and Lactobacillus plantarum

The Editor-in-Chief has retracted this article (Wang et al. 2018) because the authors do not have ownership of the data they report. An investigation by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has concluded that the data reported in this article are the sole property of the CSIRO. Mingbo Wu agrees with this retraction. Dan Wang, Yao Liu, Die Lv, Xueli Hu, Qiumei Zhong and Ye Zhao have not responded to correspondence about this retraction

Revue De La Litterature : Cymbopogon citratus (Dc) Stapf, Ethnopharmacologie, Phytochimie Et Activites Pharmacologiques

Cymbopogon citratus (D.C.) Stapf est une herbe aromatique vivace appartenant à la famille des Poaceaes (Gramineas), utilisé traditionnellement pour soigner diverses maladies. De nombreuses études ont montré que cette plante possède des propriétés antimicrobiennes, antifongiques, anti-inflammatoires, anti cancérigènes, antidiabétiques, anti-oxydantes, cardiovasculaires, insecticides et antiparasitaires. Les molécules les plus importantes responsables de ses propriétés thérapeutiques sont : citral, myrcène, limonène, tanins, nerol acetate, neryl acetate, linalool, geranyl acetate, terpin-4-ol, â-caryophyllène, geraniol, saponosides, composés phénoliques, flavonoïdes. Bien que les extraits du C citratus ou certains de ses constituants tels que le citral, le myrcène et le limonène soient toxiques à forte dose, aucun cas d’intoxication relatif à l’utilisation du C citratus n’a été décrit dans la littérature. Cet article est un résumé non-exhaustif de la description botanique, de l’ethnopharmacologie, de la phytochimie, de l’activité pharmacologique et de la toxicité du C citratus.Mots clés: Cymbopogon citratus, citral, â-myrcène, antimicrobien, antifongique, toxicitéEnglish AbstractCymbopogon citratus (D.C.) Stapf is a perennial aromatic herb belonging to Poaceaes (Gramineas) traditionally used to treat various diseases. Many studies have shown that this plant has an antimicrobial, antifungal, anti-inflammatory, antineoplastic, antidiabetic, antioxidant, cardiovascular, insecticide and pesticide activities. The therapeutic properties were related to citral, â myrcene, limonene, tannins, nerol acetate, neryl acetate, linalool, geranyl acetate, terpin-4-ol, â-caryophyllene, geraniol, saponins, flavonoids, phenolic compounds. Although extracts of C. citratus or some of its components such as citral, â-myrcene and limonene are toxic at high doses, no cases of human intoxication of C. citratus was described. This article is a non-exhaustive summary of the botanical description, ethnopharmacology, phytochemistry, pharmacological activity and toxicity of C. citratus.Keywords: Cymbopogon citratus, citral, â-myrcene, antimicrobial, antifungal, toxicit

Contribution of Disulfide Bridges to the Thermostability of a Type A Feruloyl Esterase from Aspergillus usamii.

The contribution of disulfide bridges to the thermostability of a type A feruloyl esterase (AuFaeA) from Aspergillus usamii E001 was studied by introducing an extra disulfide bridge or eliminating a native one from the enzyme. MODIP and DbD, two computational tools that can predict the possible disulfide bridges in proteins for thermostability improvement, and molecular dynamics (MD) simulations were used to design the extra disulfide bridge. One residue pair A126-N152 was chosen, and the respective amino acid residues were mutated to cysteine. The wild-type AuFaeA and its variants were expressed in Pichia pastoris GS115. The temperature optimum of the recombinant (re-) AuFaeAA126C-N152C was increased by 6°C compared to that of re-AuFaeA. The thermal inactivation half-lives of re-AuFaeAA126C-N152C at 55 and 60°C were 188 and 40 min, which were 12.5- and 10-folds longer than those of re-AuFaeA. The catalytic efficiency (kcat/Km) of re-AuFaeAA126C-N152C was similar to that of re-AuFaeA. Additionally, after elimination of each native disulfide bridge in AuFaeA, a great decrease in expression level and at least 10°C decrease in thermal stability of recombinant AuEaeA variants were also observed

Effect of Decaffeinated Green Tea Polyphenols on Body Fat and Precocious Puberty in Obese Girls: A Randomized Controlled Trial

Background: Obesity has been reported to be an important contributing factor for precocious puberty, especially in girls. The effect of green tea polyphenols on weight reduction in adult population has been shown, but few related studies have been conducted in children. This study was performed to examine the effectiveness and safety of decaffeinated green tea polyphenols (DGTP) on ameliorating obesity and early sexual development in girls with obesity. Design: This is a double-blinded randomized controlled trial. Girls with obesity aged 6–10 years old were randomly assigned to receive 400 mg/day DGTP or isodose placebo orally for 12 weeks. During this period, all participants received the same instruction on diet and exercise from trained dietitians. Anthropometric measurements, secondary sexual characteristics, B-scan ultrasonography of uterus, ovaries and breast tissues, and related biochemical parameters were examined and assessed pre- and post-treatment. Results: Between August 2018 and January 2020, 62 girls with obesity (DGTP group n = 31, control group n = 31) completed the intervention and were included in analysis. After the intervention, body mass index, waist circumference, and waist-to-hip ratio significantly decreased in both groups, but the percentage of body fat (PBF), serum uric acid (UA), and the volumes of ovaries decreased significantly only within the DGTP group. After controlling confounders, DGTP showed a significantly decreased effect on the change of PBF (β = 2.932, 95% CI: 0.214 to 5.650), serum UA (β = 52.601, 95% CI: 2.520 to 102.681), and ovarian volumes (right: β = 1.881, 95% CI: 0.062 to 3.699, left: β = 0.971, 95% CI: 0.019 to 1.923) in girls with obesity. No side effect was reported in both groups during the whole period. Conclusion: DGTP have shown beneficial effects of ameliorated obesity and postponed early sexual development in girls with obesity without any adverse effects. Clinical Trial Registration: [https://clinicaltrials.gov/ct2/show/NCT03628937], identifier [NCT03628937]