Optimizing protein delivery rate from silk fibroin hydrogel using silk fibroin-mimetic peptides conjugation

Controlled release of proteins, such as growth factors, from biocompatible silk fibroin (SF) hydrogel is valuable for its use in tissue engineering, drug delivery, and other biological systems. To achieve this, we introduced silk fibroin-mimetic peptides (SFMPs) with the repeating unit (GAGAGS)n. Using green fluorescent protein (GFP) as a model protein, our results showed that SFMPs did not affect the GFP function when conjugated to it. The SFMP-GFP conjugates incorporated into SF hydrogel did not change the gelation time and allowed for controlled release of the GFP. By varying the length of SFMPs, we were able to modulate the release rate, with longer SFMPs resulting in a slower release, both in water at room temperature and PBS at 37 °C. Furthermore, the SF hydrogel with the SFMPs showed greater strength and stiffness. The increased β-sheet fraction of the SF hydrogel, as revealed by FTIR analysis, explained the gel properties and protein release behavior. Our results suggest that the SFMPs effectively control protein release from SF hydrogel, with the potential to enhance its mechanical stability. The ability to modulate release rates by varying the SFMP length will benefit personalized and controlled protein delivery in various systems.

Functional and genomic characterization of a novel probiotic Lactobacillus johnsonii KD1 against shrimp WSSV infection

White Spot syndrome virus (WSSV) causes rapid shrimp mortality and production loss worldwide. This study demonstrates potential use of Lactobacillus johnsonii KD1 as an anti-WSSV agent for post larva shrimp cultivation and explores some potential mechanisms behind the anti-WSSV properties. Treatment of Penaeus vannamei shrimps with L. johnsonii KD1 prior to oral challenge with WSSV-infected tissues showed a significantly reduced mortality. In addition, WSSV copy numbers were not detected and shrimp immune genes were upregulated. Genomic analysis of L. johnsonii KD1 based on Illumina and Nanopore platforms revealed a 1.87 Mb chromosome and one 15.4 Kb plasmid. Only one antimicrobial resistance gene (ermB) in the chromosome was identified. Phylogenetic analysis comparing L. johnsonii KD1 to other L. johnsonii isolates revealed that L. johnsonii KD1 is closely related to L. johnsonii GHZ10a isolated from wild pigs. Interestingly, L. johnsonii KD1 contains isolate-specific genes such as genes involved in a type I restriction-modification system and CAZymes belonging to the GT8 family. Furthermore, genes coding for probiotic survival and potential antimicrobial/anti-viral metabolites such as a homolog of the bacteriocin helveticin-J were found. Protein-protein docking modelling suggests the helveticin-J homolog may be able to block VP28-PmRab7 interactions and interrupt WSSV infection.

Disruption of a DUF247 Containing Protein Alters Cell Wall Polysaccharides and Reduces Growth in Arabidopsis

Plant cell wall biosynthesis is a complex process that requires proteins and enzymes from glycan synthesis to wall assembly. We show that disruption of At3g50120 (DUF247-1), a member of the DUF247 multigene family containing 28 genes in Arabidopsis, results in alterations to the structure and composition of cell wall polysaccharides and reduced growth and plant size. An ELISA using cell wall antibodies shows that the mutants also exhibit ~50% reductions in xyloglucan (XyG), glucuronoxylan (GX) and heteromannan (HM) epitopes in the NaOH fraction and ~50% increases in homogalacturonan (HG) epitopes in the CDTA fraction. Furthermore, the polymer sizes of XyGs and GXs are reduced with concomitant increases in short-chain polymers, while those of HGs and mHGs are slightly increased. Complementation using 35S:DUF247-1 partially recovers the XyG and HG content, but not those of GX and HM, suggesting that DUF247-1 is more closely associated with XyGs and HGs. DUF247-1 is expressed throughout Arabidopsis, particularly in vascular and developing tissues, and its disruption affects the expression of other gene members, indicating a regulatory control role within the gene family. Our results demonstrate that DUF247-1 is required for normal cell wall composition and structure and Arabidopsis growth.

The effects of geographical distributions of buildings and roads on the spatiotemporal spread of canine rabies: An individual-based modeling study

Rabies is a fatal disease that has been a serious health concern, especially in developing countries. Although rabies is preventable by vaccination, the spread still occurs sporadically in many countries, including Thailand. Geographical structures, habitats, and behaviors of host populations are essential factors that may result in an enormous impact on the mechanism of propagation and persistence of the disease. To investigate the role of geographical structures on the transmission dynamics of canine rabies, we developed a stochastic individual-based model that integrates the exact configuration of buildings and roads. In our model, the spatial distribution of dogs was estimated based on the distribution of buildings, with roads considered to facilitate dog movement. Two contrasting areas with high- and low-risk of rabies transmission in Thailand, namely, Hatyai and Tepha districts, were chosen as study sites. Our modeling results indicated that the distinct geographical structures of buildings and roads in Hatyai and Tepha could contribute to the difference in the rabies transmission dynamics in these two areas. The high density of buildings and roads in Hatyai could facilitate more rabies transmission. We also investigated the impacts of rabies intervention, including reducing the dog population, restricting owned dog movement, and dog vaccination on the spread of canine rabies in these two areas. We found that reducing the dog population alone might not be sufficient for preventing rabies transmission in the high-risk area. Owned dog confinement could reduce more the likelihood of rabies transmission. Finally, a higher vaccination coverage may be required for controlling rabies transmission in the high-risk area compared to the low-risk area.

Hepcidin induces intestinal calcium uptake while suppressing iron uptake in Caco-2 cells

Abnormal calcium absorption and iron overload from iron hyperabsorption can contribute to osteoporosis as found in several diseases, including hemochromatosis and thalassemia. Previous studies in thalassemic mice showed the positive effects of the iron uptake suppressor, hepcidin, on calcium transport. However, whether this effect could be replicated in other conditions is not known. Therefore, this study aimed to investigate the effects of hepcidin on iron and calcium uptake ability under physiological, iron uptake stimulation and calcium uptake suppression. To investigate the potential mechanism, effects of hepcidin on the expression of iron and calcium transporter and transport-associated protein in Caco-2 cells were also determined. Our results showed that intestinal cell iron uptake was significantly increased by ascorbic acid together with ferric ammonium citrate (FAC), but this phenomenon was suppressed by hepcidin. Interestingly, hepcidin significantly increased calcium uptake under physiological condition but not under iron uptake stimulation. While hepcidin significantly suppressed the expression of iron transporter, it had no effect on calcium transporter expression. This indicated that hepcidin-induced intestinal cell calcium uptake did not occur through the stimulation of calcium transporter expression. On the other hand, 1,25(OH)₂D₃ effectively induced intestinal cell calcium uptake, but it did not affect intestinal cell iron uptake or iron transporter expression. The 1,25(OH)₂D₃-induced intestinal cell calcium uptake was abolished by 12 mM CaCl₂; however, hepcidin could not rescue intestinal cell calcium uptake suppression by CaCl₂. Taken together, our results showed that hepcidin could effectively and concurrently induce intestinal cell calcium uptake while reducing intestinal cell iron uptake under physiological and iron uptake stimulation conditions, suggesting its therapeutic potential for inactive calcium absorption, particularly in thalassemic patients or patients who did not adequately respond to 1,25(OH)₂D₃.

Significantly Improved Colossal Dielectric Properties and Maxwell-Wagner Relaxation of TiO2-Rich Na1/2Y1/2Cu3Ti4+xO12 Ceramics

In this work, the colossal dielectric properties and Maxwell-Wagner relaxation of TiO2-rich Na1/2Y1/2Cu3Ti4+xO12 (x = 0-0.2) ceramics prepared by a solid-state reaction method are investigated. A single phase of Na1/2Y1/2Cu3Ti4O12 is achieved without the detection of any impurity phase. The highly dense microstructure is obtained, and the mean grain size is significantly reduced by a factor of 10 by increasing Ti molar ratio, resulting in an increased grain boundary density and hence grain boundary resistance (Rgb). The colossal permittivities of ε' ~ 0.7-1.4 × 104 with slightly dependent on frequency in the frequency range of 102-106 Hz are obtained in the TiO2-rich Na1/2Y1/2Cu3Ti4+xO12 ceramics, while the dielectric loss tangent is reduced to tanδ ~ 0.016-0.020 at 1 kHz due to the increased Rgb. The semiconducting grain resistance (Rg) of the Na1/2Y1/2Cu3Ti4+xO12 ceramics increases with increasing x, corresponding to the decrease in Cu+/Cu2+ ratio. The nonlinear electrical properties of the TiO2-rich Na1/2Y1/2Cu3Ti4+xO12 ceramics can also be improved. The colossal dielectric and nonlinear electrical properties of the TiO2-rich Na1/2Y1/2Cu3Ti4+xO12 ceramics are explained by the Maxwell-Wagner relaxation model based on the formation of the Schottky barrier at the grain boundary.

Significantly Enhanced Dielectric Properties of Ag-Deposited (In1/2Nb1/2)0.1Ti0.9O2/PVDF Polymer Composites

The enhanced dielectric permittivity (ε') while retaining a low loss tangent (tanδ) in silver nanoparticle-(In1/2Nb1/2)0.1Ti0.9O2/poly(vinylidene fluoride) (Ag-INTO/PVDF) composites with different volume fractions of a filler (fAg-INTO) was investigated. The hybrid particles were fabricated by coating Ag nanoparticles onto the surface of INTO particles, as confirmed by X-ray diffraction. The ε' of the Ag-INTO/PVDF composites could be significantly enhanced to ~86 at 1 kHz with a low tanδ of ~0.044. The enhanced ε' value was approximately >8-fold higher than that of the pure PVDF polymer for the composite with fAg-INTO = 0.5. Furthermore, ε' was nearly independent of frequency in the range of 102-106 Hz. Therefore, filling Ag-INTO hybrid particles into a PVDF matrix is an effective way to increase ε' while retaining a low tanδ of polymer composites. The effective medium percolation theory model can be used to fit the experimental ε' values with various fAg-INTO values. The greatly increased ε' primarily originated from interfacial polarization at the conducting Ag nanoparticle-PVDF and Ag-INTO interfaces, and it was partially contributed by the high ε' of INTO particles. A low tanδ was obtained because the formation of the conducting network in the polymer was inhibited by preventing the direct contact of Ag nanoparticles.

Cymbalcloeon gen. nov., an incredible new mayfly genus (Ephemeroptera: Baetidae) from Thailand

The genus Cymbalcloeon gen. nov. (Ephemeroptera: Baetidae) is established for a new species Cymbalcloeon sartorii sp. nov. from Thailand, based on larval stage. This genus is unique among all of the Baetidae by the presence of three pairs of single gills on segments V-VII, ventrally oriented to cover the sterna VI-IX. Cymbalcloeon sartorii gen. nov. et sp. nov. presents unique or rare morphological characters such as a deeply concave margin between the prostheca and mola, without setae; a very large subtriangular process of the left mandible; a maxillary palp segment II with scarce and very long setae; almost completely fused labial palp segments II and III with numerous very long setae; elongate tarsal claw with two rows of teeth; a shagreen surface of the terga and paraproct; and a very reduced body size. The gills of the new genus move very quickly during respiration and present a near-synchronous protraction. Due to the very derived larval morphological character and the unknown imaginal stage, the exact phylogenetic position of the genus remains unclear; it most certainly belongs to the concept of Anteropatellata and is possibly closely related to the genus Baetopus.