Membrane-Anchoring, Comb-Like Pseudopeptides for Efficient, pH-Mediated Membrane Destabilization and Intracellular Delivery

Endosomal release has been identified as a rate-limiting step for intracellular delivery of therapeutic agents, in particular macromolecular drugs. Herein, we report a series of synthetic pH-responsive, membrane-anchoring polymers exhibiting dramatic endosomolytic activity for efficient intracellular delivery. The comb-like pseudopeptidic polymers were synthesized by grafting different amounts of decylamine (NDA), which act as hydrophobic membrane anchors, onto the pendant carboxylic acid groups of a pseudopeptide, poly­(l-lysine iso-phthalamide). The effects of the hydrophobic relatively long alkyl side chains on aqueous solution properties, cell membrane destabilization activity, and in-vitro cytotoxicity were investigated. The optimal polymer containing 18 mol % NDA exhibited limited hemolysis at pH 7.4 but induced nearly complete membrane destabilization at endosomal pH within only 20 min. The mechanistic investigation of membrane destabilization suggests the polymer-mediated pore formation. It has been demonstrated that the polymer with hydrophobic side chains displayed a considerable endosomolytic ability to release endocytosed materials into the cytoplasm of various cell lines, which is of critical importance for intracellular drug delivery applications

Figure 2 in A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species

Figure 2. The whole skeleton of the holotype Tongtianlong limosus gen. et sp. nov. in dorsal view (a) and lateral view (b). Scale bar = 10 cm

Figure 4 in A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species

Figure 4. The photograph (a) and line drawing (b) of the skull: Tongtianlong limosus gen. et sp. nov. in right lateral view. Abbreviations: aof, antorbital fenestra; bc, braincase; d, dentary; emf, external mandibular fenestra; eo, exoccipital; f, frontal; j, jugal; l, lacrimal; ltf: lower temporal fenestra; m, maxilla; n, nasal; nar, narial opening; npc, nasopharyngeal canal; o, orbit; p, parietal; pm, premaxilla; pno, pneumatic opening; po, postorbital; q, quadrate; qj, quadratojugal; sa, surangular; sq, squamosal; stf, supratemporal fenestra. Scale bar = 5 cm

Figure 1 in A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species

Figure 1. Map of the fossil locality near Ganzhou, Iiangxi Province, southern China. The solid five-pointed star represents the fossil site. Modified from Lü et al. 29

Figure 5 in A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species

Figure 5. An artistic reconstruction, showing the last-ditch struggle of Tongtianlong limosus as it was mired in mud, one possible, but highly speculative, interpretation for how the specimen was killed and buried (Drawn by Zhao Chuang)

Molecular characterization, expression pattern and function analysis of the <i>OsHSP90</i> family in rice

<p>The HSP90 is an abundant chaperone protein that is conserved in all eukaryotes. The main function of HSP90 is to assist other proteins to fold properly. In this study, we uncovered and analysed nine OsHSP90 (OsHSP90-1--OsHSP90-9) family members in rice <i>Nipponbare</i>, in which three distinct motifs were identified. All the HSP90 proteins were classified into three major groups (I, II, III) by phylogenetic analysis. The expression of <i>OsHSP90</i> family in 10 tissues was examined by real-time polymerase chain reaction (PCR). <i>OsHSP90-4</i>, <i>OsHSP90-6</i> and <i>OsHSP90-7</i> had high expression, while <i>OsHSP90-5</i> and <i>OsHSP90-8</i> had very low expression across almost all 10 samples. The gene that encodes <i>OsHSP90-1</i> was preferentially expressed in embryo at 14 days after flowering. It has been reported that some heat shock proteins were up-regulated in response to heat or other stresses. However, in our study the expression pattern of <i>OsHSP90</i> genes is heterogeneous under a range of stress conditions. The expression of <i>OsHSP90-2</i> and <i>OsHSP90-4</i> was up-regulated under drought, salt, cold and heat conditions, while the expression of <i>OsHSP90-3</i> and <i>OsHSP90-5</i> was down-regulated under salt and drought conditions. <i>OsHSP90-7</i> and <i>OsHSP90-9</i> were down-regulated only under drought conditions. <i>OsHSP90-6</i> did not change its expression across all conditions compared to control. Overexpression of <i>OsHSP90-2</i> in <i>E. coli</i> could enhance cell viability and significantly improved resistance to heat, high salinity and drought stress conditions. The results presented here may provide new insights into the function of <i>OsHSP90</i> family in rice.</p

Potentiating the Immune Responses of HBsAg-VLP Vaccine Using a Polyphosphoester-Based Cationic Polymer Adjuvant

Virus-like particle (VLP)-based vaccines are required to be associated with a suitable adjuvant to potentiate their immune responses. Herein, we report a novel, biodegradable, and biocompatible polyphosphoester-based amphiphilic cationic polymer, poly(ethylene glycol)-b-poly(aminoethyl ethylene phosphate) (PEG–PAEEP), as a Hepatitis B surface antigen (HBsAg)-VLP vaccine adjuvant. The polymer adjuvant effectively bound with HBsAg-VLP through electrostatic interactions to form a stable vaccine nanoformulation with a net positive surface charge. The nanoformulations exhibited enhanced cellular uptake by macrophages. HBsAg-VLP/PEG–PAEEP induced a significantly higher HBsAg-specific IgG titer in mice than HBsAg-VLP alone after second immunization, indicative of the antigen-dose sparing advantage of PEG–PAEEP. Furthermore, the nanoformulations exhibited a favorable biocompatibility and in vivo tolerability. This work presents the PEG–PAEEP copolymer as a promising vaccine adjuvant and as a potentially effective alternative to aluminum adjuvants

Molecular characterization and function analysis of the rice <i>OsDUF946</i> family

<p>The domain of unknown function DUF946 family consists of plant proteins with an average length of around 239 residues that have no characterized function. The gene family needs deeper characterization and functional analysis of its members. In this study, we report five <i>OsDUF</i><i>946</i> (<i>OsDUF946.1</i>–<i>OsDUF946.5</i>) family members in rice <i>Nipponbare</i> with three distinct motifs. All the OsDUF946 proteins were classified into three major groups (I, II, III) by phylogenetic analysis. Real-time polymerase chain reaction showed that the expression patterns of the five <i>OsDUF946</i> family members were different in 15 different rice tissues as well as under various stress conditions and abscisic acid treatment. The expression of <i>OsDUF946.1</i> was significantly downregulated under salt, cold and heat stress, while the expression of <i>OsDUF946.4</i> and <i>OsDUF946.5</i> was significantly upregulated under drought and salt conditions. Overexpression of <i>OsDUF946.4</i> in <i>E</i><i>scherichia</i> <i>coli</i> significantly improved the resistance to salt and drought, while overexpression of <i>OsDUF946.5</i> in <i>E. coli</i> did not have such an effect. The obtained results provide a starting point for further research into the function of the <i>OsDUF946</i> family in rice.</p

Molecular characterization, expression pattern and function analysis of the rice <i>OsDUF866</i> family

<p>Domain-of-unknown function (DUF) proteins represent a number of gene families with no functional annotation in the Pfam database. So far, the <i>DUF866</i> family has not been characterized, and no member has been functionally studied. In this study, we uncovered and analysed four OsDUF866 (OsDUF866.1–OsDUF866.4) family members in rice <i>Nipponbare</i>, in which three distinct motifs were identified. The expression of <i>OsDUF866</i> family in nine tissues was examined by real-time polymerase chain reaction (PCR), and the highest expression of four genes members was found in embryos at 14 days after flowering. We performed real-time PCR to examine the expression of <i>OsDUF866</i> family under abiotic stress and abscisic acid (ABA) treatment conditions. The expression level of <i>OsDUF866.1</i> displayed significant decrease under drought and salt conditions, while significant increase under heat conditions. The expression level of <i>OsDUF866.2</i> displayed significant decrease under drought conditions. The expression level of <i>OsDUF866.3</i> was significantly elevated under drought and cold, while lowered under heat conditions. The expression level of <i>OsDUF866.4</i> was increased under cold and heat conditions, while decreased under drought conditions. Interestingly, the expression level of <i>OsDUF866</i> members was approximately constant under ABA treatment conditions. Overexpression of <i>OsDUF866.1</i> in <i>Escherichia coli</i> could enhance cell viability and significantly improve the resistance to heat stress conditions. The results may provide new insights into the function of <i>OsDUF866</i> family in rice.</p

Highly Luminescent and Nontoxic Amine-Capped Nanoparticles from Porous Silicon: Synthesis and Their Use in Biomedical Imaging

Stable and brightly luminescent amine-terminated Si nanoparticles (SiNPs) have been synthesized from electrochemically etched porous silicon (PSi). The surface amine termination was confirmed by FTIR, NMR, and XPS studies. The mean diameter of the crystal core of 4.6 nm was measured by transmission electron microscopy (TEM), which is in a good agreement with the size obtained by dynamic light scattering (DLS). The dry, amine-terminated product can be obtained from bulk silicon wafers in less than 4 h. This represents a significant improvement over similar routines using PSi where times of >10 h are common. The emission quantum yield was found to be about 22% and the nanoparticles exhibited an exceptional stability over a wide pH range (4–14). They are resistant to aging over several weeks. The amine-terminated SiNPs showed no significant cytotoxic effects toward HepG2 cells, as assessed with MTT assays