An Oral Male Courtship Pheromone Terminates the Response of Nasonia vitripennis Females to the Male-Produced Sex Attractant

Sex pheromones are crucial for mate finding in many animals. Long-range attraction, mate recognition, and the elicitation of sexual receptiveness during courtship are typically mediated by different compounds. It is widely unknown, however, how the different components of a species’ pheromone system influence each other. Here, we demonstrated in the parasitoid wasp Nasonia vitripennis that females quickly cease to respond to the male sex attractant after they contact a male’s oral secretion during courtship. We used this behavioral switch to monitor the fractionation of head extracts from male wasps for identification of the bioactive compounds as a blend of ethyl oleate, ethyl linoleate, and ethyl α-linolenate. This is the first identification of a cephalic courtship pheromone in parasitic Hymenoptera. Plasticity in pheromone-mediated sexual behavior of female insects has hitherto been attributed to the transfer of bioactive proteinaceous molecules with the male ejaculate. The pheromone interaction reported here sheds new light on the sexual communication of insects by showing that the sex pheromone response of females can be terminated by males independent of sperm transfer.     

High Chemical Diversity in a Wasp Pheromone: a Blend of Methyl 6-Methylsalicylate,Fatty Alcohol Acetates and Cuticular Hydrocarbons Releases Courtship Behavior in the Drosophila Parasitoid Asobara tabida

Wasps of genus Asobara, a larval parasitoid of Drosophila, have become model organisms for the study of host-parasite interactions. However, little is known about the role of pheromones in locating mates and courtship behavior in this genus. In the present study, we aimed to identify the female courtship pheromone in Asobara tabida. The chemical compositions of solvent extracts from male and female wasps were analyzed by GC/MS. These extracts, fractions thereof, and synthetic pheromone candidates were tested for their activity in behavioral bioassays. The results demonstrate that the courtship pheromone of A. tabida is characterized by a remarkable chemical diversity. A multi-component blend of female-specific compounds including methyl 6-methylsalicylate (M6M), fatty alcohol acetates (FAAs), and cuticular hydrocarbons (CHCs) released male courtship behavior. Using a combinatory approach that included both purified natural products and synthetic analogs, it was shown that none of the three chemical classes alone was sufficient to release a full behavioral response in males. However, a blend of M6M and FAAs or combinations of one or both of these with female-derived CHCs resulted in wing-fanning responses by males comparable to those elicited by the crude extract of females. Thus, components from all three chemical classes contribute to the bioactivity of the pheromone, but none of the elements plays a key role or is irreplaceable. The fact that one of the FAAs, vaccenyl acetate, is also used as a kairomone by Asobara females to locate Drosophila hosts suggests that a pre-existing sensory responsiveness to vaccenyl acetate might have been involved in the evolution of the female sex pheromone in Asobara.     

Preparation and characterization of lactitol-based poly(ether polyol)s for rigid polyurethane foam

Propoxylation of lactitol [4-O-β-D -galactopyranosyl-D -glucitol] under alkaline conditions afforded poly(ether polyol)s (PEP) which have been characterized by their unsaturation content, alpha color, hydroxyl number, viscosity, hygroscopicity, and molecular weight distribution. The analogous sucrose-based PEP were prepared for comparison. Lactitol was found to require shorter reaction times and produced lighter-colored polyols than did sucrose. Polyols produced from lactitol displayed similar physical properties to sucrose-based PEP. Molecular weight analysis by GPC using the universal calibration method showed lactitol PEP to have polydispersities between 1.04 and 1.07. Negligible decomposition of lactitol during propoxylation was confirmed by ¹³C-NMR and GPC. ¹H-NMR of trifluoroacetyl derivatives of lactitol PEP afforded secondary determination of M_n. In addition, rigid polyurethane foams (PURF) formulated with lactitol-, sucrose-, or commercial sucrose–glycerin-based polyols and PAPI 27 were prepared and characterized. Lactitol-based PURF were found to compare favorably with sucrose-based foams, displaying a density and compressive strength of 28.9 kg/m³ and 1.213 × 10⁵ N/M², respectively. © 1996 John Wiley & Sons, Inc.     

Covalently Immobilized Regenerable Immunoaffinity Layer with Orientation-Controlled Antibodies Based on Z-Domain Autodisplay

A regenerable immunoaffinity layer comprising covalently immobilized orientation-controlled antibodies was developed for use in a surface plasmon resonance (SPR) biosensor. For antibody orientation control, antibody-binding Z-domain-autodisplaying Escherichia coli (E. coli) cells and their outer membrane (OM) were utilized, and a disuccinimidyl crosslinker was employed for covalent antibody binding. To fabricate the regenerable immunoaffinity layer, capture antibodies were bound to autodisplayed Z-domains, and then treated with the crosslinker for chemical fixation to the Z-domains. Various crosslinkers, namely disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS) and poly (ethylene glycol)-ylated bis (sulfosuccinimidyl)suberate (BS(PEG)₅), were evaluated, and DSS at a concentration of 500 μM was confirmed to be optimal. The E. coli-cell-based regenerable HRP immunoassay was evaluated employing three sequential HRP treatment and regeneration steps. Then, the Oms of E. coli cells were isolated and layered on a microplate and regenerable OM-based HRP immunoassaying was evaluated. Five HRP immunoassays with four regeneration steps were found to be feasible. This regenerable, covalently immobilized, orientation-controlled OM-based immunoaffinity layer was applied to an SPR biosensor, which was capable of quantifying C-reactive protein (CRP). Five regeneration cycles were repeated using the demonstrated immunoaffinity layer with a signal difference of <10%.     

Pre-adolescent children exhibit lower aerosol particle volume emissions than adults for breathing,speaking, singing and shouting

Speaking and singing are activities linked to increased aerosol particle emissions from the respiratory system, dependent on the utilized vocal intensity. As a result, these activities have experienced considerable restrictions in enclosed spaces since the onset of the COVID-19 pandemic due to the risk of infection from the SARS-CoV-2 virus, transmitted by virus-carrying aerosols. These constraints have affected public education and extracurricular activities for children as well, from in-person music instruction to children’s choirs. However, existing risk assessments for children have been based on emission measurements of adults. To address this, we measured the particle emission rates of 15 pre-adolescent children, all eight to ten years old, with a laser particle counter for the test conditions: breathing at rest, speaking, singing and shouting. Compared with values taken from 15 adults, emission rates for breathing, speaking and singing were significantly lower for children. Particle emission rates were reduced by a factor of 4.3 across all conditions, whereas emitted particle volume rates were reduced by a factor of 4.8. These data can supplement SARS-CoV-2 risk management scenarios for various school and extracurricular settings.     

圆筒织物的连续脱水开布

详细描述了Suvac Cut脱水开幅机.与离心脱水开幅机相比,叙述了这一连续工艺的优点.利用真空脱水技术,阔幅圆筒织物可在连续工艺中脱水和开幅,     

Synthesis and SAR of Tetracyclic Inhibitors of Protein Kinase CK2 Derived from Furocarbazole W16

The serine/threonine kinase CK2 modulates the activity of more than 300 proteins and thus plays a crucial role in various physiological and pathophysiological processes including neurodegenerative disorders of the central nervous system and cancer. The enzymatic activity of CK2 is controlled by the equilibrium between the heterotetrameric holoenzyme CK2α₂β₂ and its monomeric subunits CK2α and CK2β. A series of analogues of W16 ((3aR,4S,10S,10aS)-4-{[(S)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-10-(3,4,5-trimethoxyphenyl)-4,5,10,10a-tetrahydrofuro[3,4-b]carbazole-1,3(3aH)-dione ((+)- 3 a )) was prepared in an one-pot, three-component Levy reaction. The stereochemistry of the tetracyclic compounds was analyzed. Additionally, the chemically labile anhydride structure of the furocarbazoles 3 was replaced by a more stable imide ( 9 ) and N-methylimide ( 10 ) substructure. The enantiomer (−)- 3 a (K_i=4.9 μM) of the lead compound (+)- 3 a (K_i=31 μM) showed a more than sixfold increased inhibition of the CK2α/CK2β interaction (protein-protein interaction inhibition, PPII) in a microscale thermophoresis (MST) assay. However, (−)- 3 a did not show an increased enzyme inhibition of the CK2α₂β₂ holoenzyme, the CK2α subunit or the mutated CK2α′ ^C336S subunit in the capillary electrophoresis assay. In the pyrrolocarbazole series, the imide (−)- 9 a (K_i=3.6 μM) and the N-methylimide (+)- 10 a (K_i=2.8 μM) represent the most promising inhibitors of the CK2α/CK2β interaction. However, neither compound could inhibit enzymatic activity. Unexpectedly, the racemic tetracyclic pyrrolocarbazole (±)- 12 , with a carboxy moiety in the 4-position, displays the highest CK2α/CK2β interaction inhibition (K_i=1.8 μM) of this series of compounds.     

Site-Directed Immobilization of an Engineered Bone Morphogenetic Protein 2 (BMP2) Variant to Collagen-Based Microspheres Induces Bone Formation In Vivo

For the treatment of large bone defects, the commonly used technique of autologous bone grafting presents several drawbacks and limitations. With the discovery of the bone-inducing capabilities of bone morphogenetic protein 2 (BMP2), several delivery techniques were developed and translated to clinical applications. Implantation of scaffolds containing adsorbed BMP2 showed promising results. However, off-label use of this protein-scaffold combination caused severe complications due to an uncontrolled release of the growth factor, which has to be applied in supraphysiological doses in order to induce bone formation. Here, we propose an alternative strategy that focuses on the covalent immobilization of an engineered BMP2 variant to biocompatible scaffolds. The new BMP2 variant harbors an artificial amino acid with a specific functional group, allowing a site-directed covalent scaffold functionalization. The introduced artificial amino acid does not alter BMP2′s bioactivity in vitro. When applied in vivo, the covalently coupled BMP2 variant induces the formation of bone tissue characterized by a structurally different morphology compared to that induced by the same scaffold containing ab-/adsorbed wild-type BMP2. Our results clearly show that this innovative technique comprises translational potential for the development of novel osteoinductive materials, improving safety for patients and reducing costs.     

Effects of pretreatments on colour alterations of litchi during drying and storage

The objective of this research was to study the effect of osmotic pretreatment with combined anti-browning agents (acid, glycerol and/or trehalose) on the colour characteristics of dried litchi after drying and during 5 months of storage compared to samples without pretreatment. The pretreated samples showed good inhibition of polyphenol oxidase activity when compared with the control, while the total phenolic contents in the dried products were not reduced. The results demonstrated that water activity, lightness difference, chroma, degree of browning (DB), and 5-hydroxymethylfurfural values of all pretreated samples increased, while hue angle decreased with storage time. Samples pretreated with glycerol showed the best potential for browning retardation, followed by glycerol combined with trehalose, and trehalose, respectively. In addition, the colour parameters were used to calculate the luminescence values, representing the data in grey scale, which were correlated with a non-enzymatic browning index. The results showed grey value could be adequately used to represent the DB of dried litchi with r ² value of 0.92.