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关键词： Dermanyssus gallinae   Enolase   Gene expression   Plasminogen receptor  

摘要： Enolase, a multifunctional glycolytic enzyme, is known to act as a plasminogen receptor in many species, involved in the pivotal processes such as motility, adhesion, invasion, growth, and differentiation of the parasites. Knowledge on the function of enolase from Dermanyssus gallinae is very limited. Here we report on the molecular cloning, enzymatic activity, tissue distribution and plasminogen binding activity of enolase from D. gallinae (DgENO). The full-length of cDNA was 1305 bp, specifying a peptide of 434 amino acids. Bioinformatics analysis showed that DgENO was highly conserved compared with a range of organisms, indicating the potentially similar functions in D. gallinae. A recombinant DgENO (rDgENO) protein was produced and characterized, it catalyzed the dehydration of 2-phospho-D-glycerate to phosphoenolpyruvate, the optimal pH was 7.5. Polyclonal antibodies were generated in mice and western blotting indicated that antiserum specifically recognized the native enolase in the somatic extracts from D. gallinae. Immunohistochemical staining of mite sections revealed that the distribution of DgENO was ubiquitous with high level in salivary gland, mite digestive tissues and fat bodies in D. gallinae. Expression level of DgENO was observed mostly in engorged adult mites. Moreover, ELISA binding assay showed that rDgENO could bind plasminogen, and lysine analog e-aminocaproic acid significantly inhibited this binding activity, indicating that D. gallinae enolase is a receptor of plasminogen. The present study provided foundation for understanding of the biological functions of DgENO and its application in development of vaccines against D. gallinae.

关键词： Thermodynamics  

摘要： Liquid-liquid droplet reactors have garnered significant interest in biochemical applications with the obvious benefits of reduced reagent consumption, well controlled droplet size and confinement of biochemical reactions away from external interference. This Tutorial Review provides a succinct overview of widely employed liquid-liquid droplet reactors, namely single emulsions, multiple emulsions and all-aqueous emulsions, under the scope of thermodynamics, with a particular emphasis on how their intrinsic interfacial properties may endow mass transport for a variety of demands. Beyond spatially compartmentalizing a thermodynamic system, the artificial interface of droplet reactors has shown initial promising for multi-step or complex reactions. Moving forward, the artificial interface shall be tailored further towards "functional" to imitate the "intelligent" interface surrounding natural vesicles or cells.

关键词： Cell wall   Chitosan coating   Cold storage   Softening   Strawberry fruit  

摘要： Strawberry fruit is extremely perishable at least partially because of excessive softening, which can be inhibited by edible chitosan coating during ripening, but the biochemical and molecular mechanisms are not completely understood in the fruit under cold conditions. Here, changes in levels of quality attributes, cell wall constituents, activities and expression of cell wall modifying enzymes, were evaluated in strawberry fruit treated with 1.5% (w/v) chitosan coating and stored at 4 degrees C for 12 days. Chitosan coating had a significant inhibitory effect on fruit softening during cold storage, rather than other quality attributes. Chitosan coating treated fruit showed the reduction in the content of water-soluble pectin coincident with significant inhibition in activities of polygalacturonase (PG) and pectin methylesterase (PME), and expression of FaPG1 and FaPME1, relative to the controls. Activities of these two enzymes and expression of FaPG1 were significantly correlated with the contents of water-soluble pectin. Besides, the decreased link between cellulose and hemicellulose was indicated by the reduced transcript levels of FaXTH1 and FaEXP2, with significantly positive correlation. In conclusion, the effect of chitosan coating on strawberry fruit mainly involves the softening inhibition by metabolic enzymes of pectin, especially PG and PME. The results will provide insights into developing measures to control strawberry fruit softening during cold storage and cold chain logistics.

关键词： Kiwifruit   Salt stress   Antioxidant enzymes   Organic osmolytes   Principle component analysis (PCA)  

摘要： Salt stress negatively impacted growth and physiological processes in plants, and the effects involved oxidative damages within cell and cell organelles. In this study, four different genotypes (CG, KM, XX, and ZM-H) of Actinidia germplasm resources were exposed to CK, 0.3 %, and 0.6 % NaCl concentrations for 15 days. We measured the growth, physiological and biochemical indicators in leaves, shoots, and roots. The relative lateral branch length (RLBL), plant fresh weight (PFW), plant dry weight (PDW), and plant relative water contents (PRWC) were decreased in all genotypes under salinity stress. Whereas, the Salt damage index (SDI, sodium ions (Na+) and chloride ions (Cl-) increased in all kiwifruit genotypes under high salt conditions. On the contrary, the potassium ion (K+) and K+/Na+ ratio was decreased in all genotypes under higher salt conditions. For organic osmolytes, Proline increased and total soluble sugars (TSS) decreased in all genotypes under high salt. The enzymatic activities of APX, GST, and GR were increased in all kiwifruit genotypes when subjected to higher levels of NaCl stress. The salt tolerance of different kiwifruit genotypes was assessed by principal component analysis (PCA), and the order of salt tolerance was as following: ZM-H > CG > XX > KM. Hence, the ZM-H from A. valvata Dunn. possessed strong tolerance against salt stress and could be an important germplasm resource for the salt tolerance rootstock breeding program of kiwifruit.

摘要： Although mechanisms of embryonic development are similar between mice and humans, the time scale is generally slower in humans. To investigate these interspecies differences in development, we recapitulate murine and human segmentation clocks that display 2- to 3-hour and 5- to 6-hour oscillation periods, respectively. Our interspecies genome-swapping analyses indicate that the period difference is not due to sequence differences in the HES7 locus, the core gene of the segmentation clock. Instead, we demonstrate that multiple biochemical reactions of HES7, including the degradation and expression delays, are slower in human cells than they are in mouse cells. With the measured biochemical parameters, our mathematical model accounts for the two- to threefold period difference between the species. We propose that cell-autonomous differences in biochemical reaction speeds underlie temporal differences in development between species.

关键词： microwave detectors   chemical sensors   perturbation theory   microwave resonators   biochemistry   chemical variables measurement   microwave measurement   split ring resonators   frequency measurement   Q-factor measurement   numerical analysis   biological techniques   quality factor measurement   dielectric constant value   nondestructive microwave resonant sensor   modified complementary split-ring resonator   perturbation theory   nonintrusive RF biochemical sensor   aqueous biochemical detection   numerical model   frequency 6   31 GHz   frequency 6   23 MHz  

摘要： In this Letter, a non-destructive microwave resonant sensor based on the modified complementary split-ring resonator has been proposed and analysed with respect to its sensitivity for detecting the aqueous biochemicals. This technique is based on the perturbation theory and only requires to measure resonant frequency and hence, achieving a substantial reduction in the computation time and cost. The proposed sensor is designed to achieve high sensitivity performance with a measured quality factor of the sensor in the bare state,Q(B)= 631.5, at the centre frequency off(o)= 6.31 GHz. The proposed sensor has a maximum sensitivity ofS= 6.23 MHz with respect to a unit change in the dielectric constant value. A numerical model is developed for the dielectric constant of the biochemicals as a function of the resonant frequency. The proposed sensor, therefore, provides high sensitivity, simple structure layout and real-time response with cost effectiveness. The proposed structure can be a potential candidate for the non-intrusive sensing of aqueous biochemicals.

关键词： ACE2   allostery   coronavirus   drug development   protein dynamics  

摘要： Angiotensin converting enzyme 2 (ACE2) is the human receptor that interacts with the spike protein of coronaviruses, including the one that produced the 2020 coronavirus pandemic (COVID-19). Thus, ACE2 is a potential target for drugs that disrupt the interaction of human cells with SARS-CoV-2 to abolish infection. There is also interest in drugs that inhibit or activate ACE2, that is, for cardiovascular disorders or colitis. Compounds binding at alternative sites could allosterically affect the interaction with the spike protein. Herein, we review biochemical, chemical biology, and structural information on ACE2, including the recent cryoEM structures of full-length ACE2. We conclude that ACE2 is very dynamic and that allosteric drugs could be developed to target ACE2. At the time of the 2020 pandemic, we suggest that available ACE2 inhibitors or activators in advanced development should be tested for their ability to allosterically displace the interaction between ACE2 and the spike protein.

关键词： Magnetization   Medicinal plants   Menthol   Menthone   Environmentally friendly method   Salinity stress  

摘要： Due to the limitation of suitable water for crop production in the world, recycling water is among the most proper methods enhancing water efficiency and availability. One modern method, which is of economic, health, and environmental significance, and may improve water properties for plant use is water magnetization. Medicinal plants are of nutritional, economic and medical values and their growth decreases under salinity stresses. This research was hypothesized and conducted because there is not any data, to our knowledge, on the use of magnetized salty water affecting the growth and biochemical properties of peppermint (Mentha piperita L.). The experiment was a split plot design with three replicates. The main plots consisted of magnetic fields at control (M1), 100 mT (M2), 200 mT (M3), and 300 mT (M4), the sub-plots consisted of salinity treatments (NaCl) at control (S1), 4 dS/m (S2), 8 dS/m (S3), and 12 dS/m (S4), and the growth media including cocopeat (X1), palm (X2), cocopeat + perlite (V/V = 50, X3) and palm + perlite (V/V = 50, X4) were located in the subsub-plots. Different plant growth and biochemical properties including plant fresh and dry weight, plant menthol, menthone, chlorophyll and proline contents were determined. Analysis of variance indicated the significant effects of experimental treatments and their interactions on the growth and biochemistry of peppermint. Different magnetic fields significantly increased plant growth, and interestingly with increasing the salinity level the alleviating effects of magnetic field on salinity stress became more clear (significant interaction between salinity and magnetic field treatments). Cocopeat was the most efficient growth medium. At the third level of salinity (8 dS/m) just the two levels of 100 and 200 mT increased plant menthol concentration. Treatments M3S2X4 and M1S1X1 resulted in the highest (38%) and the least menthol percentage (13%), respectively. Treatments S2 and M2 and M3 significantly incre

关键词： Eugenol   Essential oil   Fish transport   Oreochromis niloticus   Stress  

摘要： This study assessed the hematological and biochemical effects of natural anesthetics used in the transport of Nile tilapia (Oreochromis niloticus) and their residual concentration in the fish fillet. One hundred fish with an average weight of 816.36 +/- 31.37 g and an average standard length of 31.27 +/- 1.42 cm were distributed among five treatments: non-transported fish;fish transported in water only (control), fish transported in water + anesthetic vehicle (ethanol 36 mu L L-1), fish transported in water + eugenol (20 mu L L-1), and fish transported in water + Ocimum basilicum essential oil (20 mu L L-1). The fish were transported in boxes (1.45 m long x 1.08 m wide x 1.03 m high, Trevisan (R)) for 2 h. Subsequently, hematological and biochemical parameters were evaluated. Meanwhile, fillet samples were removed to determine the level of residual deposition of those compounds in the fish muscle by gas chromatography-mass spectrometry (GC-MS). The fish transported with natural anesthetics showed a lower (p < .05) number of erythrocytes. Sedation with O. basilicum prevented alterations in energy metabolism, but did not prevent changes in the chloride and sodium electrolytes (p < .05). Glucose was higher (p < .05) in the fish from the eugenol group. The major components of O. basilicum essential oil were methyl chavicol (66.51%) and linalool (20.90%). The residual levels of the methyl chavicol and eugenol compounds in Nile tilapia fillets were 20.52 +/- 2.05 and 75.04 +/- 3.76 mu g kg(-1), respectively, which are below the acceptable levels of O. basilicum essential oil and eugenol for human consumption. Therefore, the natural anesthetics exhibited sedative capacity and did not cause harm, but induced alterations typical of physiological adjustments during transport stress.