Self-assembly of hydrazide-linked porous organic polymers rich in titanium for efficient enrichment of glycopeptides and phosphopeptides from human serum.

In this work, titanium-rich hydrazide-linked porous organic polymers (hydrazide-POPs-Ti4+) were synthesized using hydrazine, 2,3-dihydroxyterephthalaldehyde (DHTA) and trimethyl 1,3,5-benzenetricarboxylate (TP) as the ligands. Hydrazide-POPs-Ti4+ combined with HILIC and IMAC can be used for simultaneous enrichment of glycopeptides and phosphopeptides. The detection limit of this protocol is 0.1 fmol µL-1 for glycopeptides and 0.005 fmol µL-1 for phosphopeptides, and the selectivities are 1 : 1000 and 1 : 2000 for glycopeptides and phosphopeptides, respectively. For practical bio-sample analysis, 201 glycopeptides associated with 129 glycoproteins and 26 phosphopeptides associated with 21 phosphoproteins were selectively captured from healthy human serum, and 186 glycopeptides associated with 117 glycoproteins and 60 phosphopeptides associated with 50 phosphoproteins were enriched in the serum of breast cancer patients. Gene Ontology analysis indicated that the identified glycoproteins and phosphoproteins were linked to breast cancer, including the binding of complement component C1q and low-density lipoprotein particles, protein oxidation and complement activation, suggesting that these connected pathways are probably engaged in the disease pathology of breast cancer.

The variation profile of intestinal microbiota in blunt snout bream (Megalobrama amblycephala) during feeding habit transition.

BACKGROUND: The blunt snout bream (Megalobrama amblycephala) is one of the most important commercial herbivorous fish in China, and dietary transition is an important event in blunt snout bream development. Gut microbiota has a vital role to host animal. However, little was known about the relationship among feeding habits transition, gut microbiota and digestive enzymes of gut content. RESULTS: In this study, 186,328 high-quality reads from nine 16S rRNA libraries were obtained using the Illumina MiSeq PE300 platform. The valid sequences were classified into 388 Operational Taxonomic Units, and a total of 223 genera, belonging to 20 phyla, were identified. The clustering result of gut bacterial communities is consistently related to the clustering result of intestinal content compositions. Proteobacteria and Firmicutes constitute the 'core' gut microbiota of blunt snout bream. Cetobacterium and Rhizobium were identified as microbiological markers of gut microbiota at zooplankton-based diet stages and diet transition stages, respectively. Moreover, thirteen potential cellulose-degrading bacteria were detected in our study. The canonical redundancy analysis (RDA) revealed that the feeding habits strongly influenced the gut microbiota and the digestive enzyme activities of gut content, while the result of PICRUSt test suggests that the metabolic capacity of gut microbiota was affected by feeding habit. CONCLUSIONS: This study provided a comprehensive survey of the gut microbiota in blunt snout bream during its dietary transition period for the first time and clearly showed that the gut microbiota was strongly affected by feeding habit. This work allows us to better understand the relationship among gut microbiota, nutrition metabolism and feeding habits in vertebrate. Further, our study provides a reference for future studies investigating the metabolic adaption of herbivorous fish to shift to a vegetarian diet during their life history.

Assessing microplastics-antibiotics coexistence induced ciprofloxacin-resistant Pseudomonas aeruginosa at a water region scale.

Microplastics (MPs) waste is widespread globally in water systems. The opportunistic human pathogen Pseudomonas aeruginosa can cause serious acute and chronic infections that are notoriously difficult to treat. Ciprofloxacin (CIP) is broadly applied as an anti-P. aeruginosa drug. A growing evidence reveals that antibiotic-resistance genes-carrying Pseudomonas aeruginosa were detected on MPs forming plastisphere due to their adsorbability along with high occurrence of CIP in water environments. The MPs-niched CIP-resistant P. aeruginosa has been likely to emerge as an unignorable public health issue. Here, we offered a novel approach to assess the development of CIP-resistant P. aeruginosa under MPs-antibiotic coexistence at a water region scale. By combing the adsorption isotherm models used to estimate CIP condensation around MPs and a pharmacokinetic/pharmacodynamic-based microbial population dynamic model, we predicted the P. aeruginosa development on CIP-adsorbed MPs in waters. Our assessment revealed a high antibiotic resistance in the P. aeruginosa populations (∼50 %) with a wider range of waterborne total cell counts (∼10-2-104 cfu mL-1) among water regions in that the resistance proportion was primarily determined by CIP pollution level and relative abundance of various polymer type of MPs. We implicate that water region-specific MPs were highly likely to provide media for P. aeruginosa propagation. Our results highlight the importance of antibiotic-resistant pathogen colonization-emerging environmental medium interactions when addressing global threat from MPs pollution, in the context of MPs-antibiotics co-contamination assessment and for the continued provision of water system management.

Facile preparation of porphyrin-based porous organic polymers for specific enrichment and isolation of phosphopeptides and phosphorylated exosomes.

Exosomes, which can be used to investigate various disease processes, are novel disease markers that have been extensively studied in recent years. In this work, zirconium-rich porphyrin-based porous organic polymers (Imi-Pops-Zr) were synthesized by a facile and low-cost strategy for specific enrichment and isolation of phosphorylated peptides and exosomes. The proposed material demonstrates a low detection limit (0.5 fmol), a high selectivity (bovine serum albumin (BSA): ß-casein = 1000:1), and a loading capability of 100 mg/g for phosphopeptides. For complex practical samples, after enrichment with Imi-Pops-Zr, 4 characteristic phosphopeptides from human serum, 20 and 12 phosphopeptides from human saliva and defatted milk were detected, respectively. Besides, 74 phosphorylated peptides with 67 phosphorylation sites belonging to 61 phosphoproteins and 67 phosphorylated peptides with 63 phosphorylation sites belonging to 65 phosphoproteins were detected from the serum of normal controls and uremic patients, respectively. Biological processes, cellular components and molecular functions revealed that interleukin-6, tumor necrosis factor, high density lipoprotein and proteases binding may be associated with uremia. Furthermore, Imi-Pops-Zr was successfully used to enrich and isolate exosomes from human serum. The experimental results show that Imi-Pops-Zr has promising application in the specific enrichment of phosphorylated peptides and exosomes in complex bio-samples.

Soil-dwelling species-based biomarker as a sensitivity-risk measure of terrestrial ecosystems response to microplastics: A dose-response modeling approach.

Microplastics (MPs) dispersed throughout terrestrial ecosystems is a growing global concern, yet their potential risks on terrestrial ecosystems are poorly understood from a mechanistic viewpoint. A novel empirical approach to assess relative sensitivity-risk of terrestrial ecosystems to MPs-posed potential impacts was presented. The risk metrics based on soil-dwelling organism responses-derived biomarkers that could identify whether study regions have sensitivity-risk to MPs were developed. The recently published datasets covering geographic areas worldwide with toxicity endpoints from major soil organism groups (snail, potworm, springtail, nematode, and earthworm) were used to build relationships between species physiological alterations and MPs based on a toxicodynamic-based dose-response model. The regional pollution and species sensitivity distributions combined with a probabilistic risk model were used to compare relative ranks with MPs-associated risks using predicted thresholds. The results found that ecologically sensitive regions with severe responses to soil MPs appeared in areas polluted by sewage sludge and plastic mulching. The results also showed that ~25% of study regions suffered significant MPs-associated ecological risks. This work provides a baseline measurement tool of soil species biomarker-based thresholds for comparing regional sensitivity-risk that highlights why some regions appear to be more sensitive than others and what potential risk impact this has on MPs-polluted terrestrial ecosystems globally.

Polymeric micellar paclitaxel (Pm-Pac) prolonged overall survival for NSCLC patients without pleural metastasis.

Nanoparticle polymeric micellar paclitaxel (Pm-Pac) has been demonstrated to have a safety profile and efficacy in advanced non-small cell lung cancer (NSCLC) patients. However, whether Pm-Pac could prolong overall survival (OS) for specific advanced NSCLC patients is still unknown. In the present study, a total of 448 patients were randomly assigned (2:1) by the permuted block algorithm to receive Pm-Pac plus cisplatin or solvent-based paclitaxel (Sb-Pac) plus cisplatin (NCT02667743). We performed subgroup analysis based on metastatic status to identify the potential benefit patients. Our results indicated that the metastatic profiles were similar between the Sb-Pac plus cisplatin cohort and the Pm-Pac plus cisplatin cohort. Several subgroups (Metastases = 2, Bone metastasis, No pleural metastasis, etc.) were observed to have increased progression-free survival (PFS) due to Pm-Pac plus cisplatin. Importantly, we found the first evidence that Pm-Pac potentially prolonged OS with a favourable safety profile in NSCLC patients without pleural metastasis. Collectively, this study provides a novel perspective on the development of nanomedicine to investigate chemotherapeutic efficacy and toxicity and provides the first clinical evidence that Pm-Pac administration not only prolongs PFS but also prolongs OS with a favourable safety profile in advanced NSCLC patients without pleural metastasis.

Room-temperature growth of fluorapatite/CaCO3 heterogeneous structured composites inspired by human tooth.

Organisms can synthesize heterogeneous structures with excellent mechanical properties through mineralization, the most typical of which are teeth. The tooth is an extraordinarily resilient bi-layered material that is composed of external enamel perpendicular to the tooth surface and internal dentin parallel to the tooth surface. The synthesis of enamel-like heterostructures with good mechanical properties remains an elusive challenge. In this study, we applied a biomimetic mineralization method to grow fluorapatite/CaCO3 (FAP/CaCO3) heterogeneous structured thin films that mimic their biogenic counterparts found in teeth through a three-step pathway: coating a polymer substrate, growing a layered calcite film, and mineralization of a fluorapatite columnar array on the calcite layer. The synthetic heterostructure composites combine well and exhibit good mechanical properties comparable to their biogenic counterparts. The FAP/CaCO3 heterogeneous structured composite exhibits excellent mechanical properties, with a hardness and Young's modulus of 1.99 ± 0.02 GPa and 47.5 ± 0.6 GPa, respectively. This study provides a reasonable new idea for unique heterogeneous structured materials designed at room temperature.

Nanocage Ferritin Reinforced Polyacrylamide Hydrogel for Wearable Flexible Strain Sensors.

Biocomposite hydrogels are promising for applications in wearable flexible strain sensors. Nevertheless, the existing biocomposite hydrogels are still hard to meet all requirements, which limits the practical application. Here, inspired by the structure and composition of natural ferritin, we design a PAAm-Ferritin hybrid hydrogel through a facile method. Ferritin is uniformly distributed in the cross-linking networks and acts as a nanocage spring model, leading to the enhanced tensile strength of the hydrogel. The fracture stress is 99 kPa at 1400% maximum elongation. As fabricated PAAm-Ferritin hybrid hydrogels exhibit high toughness and low elastic modulus (21 kPa). The PAAm-Ferritin hybrid hydrogels present excellent biocompatibility and increased conductivity compared with PAAm hydrogel. Impressively, as a wearable flexible strain sensor, the PAAm-Ferritin hybrid hydrogels have high sensitivity (gauge factor = 2.06), excellent reliability, and cycling stability. This study indicates the feasibility of utilizing ferritin to synthesize functional materials, which is conducive to expanding the use of protein synthesis of materials technology and application fields.

Fate of microplastics in deep-sea sediments and its influencing factors: Evidence from the Eastern Indian Ocean.

Although microplastics (MPs) are known to be found in global oceans, their influencing factors and abundance in the deep sea remain largely unknown. Twenty-six surface sediment samples were collected in the deep basin of the Eastern Indian Ocean (EIO). This study showed that MPs abundance ranged from 30.30 particles/kg to 701.7 particles/kg, with an average of 170.5 ± 140.2 particles/kg. The MPs found in the sediment of the EIO mainly contain fragments and fibers, which account for 47.5% and 45.6%. The MPs were measured in a size range of 44-5000 µm, and the most frequently detected MPs in size of 200-500 µm. MPs were in various compositions, but most of them were found in rayon (62.2%) and polyester (25.7%). The spatial distribution of MPs in the sediments shows a decreasing trend from nearshore to the open sea. In the Bay of Bengal (BOB) and the coast of Sri Lanka (COSL), the abundance of MPs was relatively high, indicating that the spatial distribution of MPs is affected by land source input, river input, and anthropogenic activities. Principal component analysis indicated daily commodities and packaging applications/fishing accounted for 36.9% and 12.9% of the MPs occurrence in the EIO, respectively. Average MPs diversity indices for the BOB (0.87 ± 0.38), the COSL (0.64 ± 0.56), and the Eastern Indian Ocean Basin (EIOB) (0.60 ± 0.24) revealed the BOB had the most complicated MPs sources. In addition, we found that the abundance of MPs has no significant effect on organic carbon and sediment grain size. This study is the first report of MPs detection in the deep-sea sediment in the EIO and can provide a baseline of MPs pollution in this area.

Mechanically Reinforced Artificial Enamel by Mg2+-Induced Amorphous Intergranular Phases.

Amorphous intergranular phases in mature natural tooth enamel are found to provide better adhesion and could dramatically affect their mechanical performance as a structure reinforcing phase. This study successfully synthesized an amorphous intergranular phase enhanced fluorapatite array controlled by Mg2+ (FAP-M) at room temperature. Furthermore, atom probe tomography (APT) observation presents that Mg2+ is enriched at grain boundaries during the assembly of enamel-like fluorapatite arrays, leading to the formation of intergranular phases of Mg-rich amorphous calcium phosphate (Mg-ACP). APT results also demonstrated that the segregation of Mg2+ caused the chemical gradient in nanocrystalline attachment and realignment under the drive of inherent surface stress. These results indicate that the amorphous intergranular phases served like glue to connect each nanorod to reinforce the enamel-like arrays. Therefore, the as-received FAP-M artificial enamel exhibits excellent mechanical properties, with hardness and Young's modulus of 2.90 ± 0.13 GPa and 67.9 ± 3.4 GPa, which were ∼8.3 and 2.2 times higher than those of FAP arrays without controlled by Mg2+, respectively.

Bioprocess-inspired synthesis of multilayered chitosan/CaCO3 composites with nacre-like structures and high mechanical properties.

The formation of natural structures found in biological systems is wonderful and can be completed at ambient temperatures in contrast to artificial technologies wherein harsh conditions are common prerequisites. A new research direction, "bioprocess inspired manufacturing", is proposed for fabricating advanced materials with novel structures and functions. Nacre consists of an ordered multilayer structure of crystalline calcium carbonate lamellae separated by organic layers exhibiting mechanical toughness, which transcends that of its constituent components. Inspired by the nacre formation process, a microscale additive manufacturing mineralization method is proposed for achieving a multilayered organic-inorganic layered structure. In this work, layered calcite was synthesized on the surface of chitosan (CS) films at room temperature under the coordinated control of magnesium ions (Mg2+) and polyacrylic acid (PAA). The CS films and layered calcite are sequentially assembled in a layer-by-layer deposition approach to form an organic-inorganic hybrid structure. The nacre-like chitosan/CaCO3 (CS/CaCO3) composites exhibit high transparency and underwater superoleophobicity. Impressively, the hardness (2.35 ± 0.03 GPa) and Young's modulus (58.1 ± 0.5 GPa) of the as-prepared (CS/CaCO3) composites are comparable to those of their biological counterparts. This study provides a rational bioprocess-inspired room-temperature mineralization method to develop advanced composite materials with good performance.

Growth of mineralized collagen films by oriented calcium fluoride nanocrystal assembly with enhanced cell proliferation.

Bone is a highly calcified tissue with 60 wt% inorganic components. It is made up of mineralized collagen fibrils, where the platelet-like hydroxyapatite nanocrystals deposit within the collagen fibrils in an oriented manner. Inspired by the special structure and biological activity of bone, we realize the intrafibrillar mineralization of collagen films with oriented calcium fluoride nanocrystals in vitro. Amorphous calcium fluoride (ACF) precursors are generated by polyacrylic acid through polymer-induced liquid precursor processes. The precursors are ready to infiltrate and fill the gap zones laterally and then diffuse to occupy the whole space inside the collagen longitudinally. Finally, the fully mineralized collagen fibrils exhibit a single-crystal-like structure after transforming precursors to co-oriented nanocrystals under the influence of arranged collagen molecules. Expanding the collagen mineralization from 1D fibrils to 2D films, the growth of mineralized areas on the films with a reaction-limited behavior is found. The kinetic rate of growth is around 0.2-0.3 µm min-1, which depends on the pH of the solution. Furthermore, the mineralized collagen films exhibit an enhanced ability of cell proliferation over the pure collagen matrices. Understanding the mineralization of artificial collagen-based scaffolds may have broad promising potentials for bone tissue regeneration and repair in the future.

Bioinspired 3D Printable, Self-Healable, and Stretchable Hydrogels with Multiple Conductivities for Skin-like Wearable Strain Sensors.

Bioinspired hydrogels have promising prospects in applications such as wearable devices, human health monitoring equipment, and soft robots due to their multifunctional sensing properties resembling natural skin. However, the preparation of intelligent hydrogels that provide feedback on multiple electronic signals simultaneously, such as human skin receptors, when stimulated by external contact pressure remains a substantial challenge. In this study, we designed a bioinspired hydrogel with multiple conductive capabilities by incorporating carbon nanotubes into a chelate of calcium ions with polyacrylic acid and sodium alginate. The bioinspired hydrogel consolidates self-healing ability, stretchability, 3D printability, and multiple conductivities. It can be fabricated as an integrated strain sensor with simultaneous piezoresistive and piezocapacitive performances, exhibiting sensitive (gauge factor of 6.29 in resistance mode and 1.25 kPa-1 in capacitance mode) responses to subtle pressure changes in the human body, such as finger flexion, knee flexion, and respiration. Furthermore, the bioinspired strain sensor sensitively and discriminatively recognizes the signatures written on it. Hence, we expect our ideas to provide inspiration for studies exploring the use of advanced hydrogels in multifunctional skin-like smart wearable devices.

Microplastics in the western Pacific and South China Sea: Spatial variations reveal the impact of Kuroshio intrusion.

Surface currents play an essential role in the worldwide distribution of microplastics in the coastal seas and open oceans. As a branch of the western boundary currents (WBCs), Kuroshio changes seawater properties and pollutant levels of the South China Sea (SCS) during its intrusion process. To study the impact of Kuroshio intrusion on microplastics, we conducted field observations on surface water from the western Pacific (WP) and SCS. Microplastic abundances in the surface water of WP (0.02-0.10 particles m-3) were generally lower than those in the SCS (0.05-0.26 particles m-3). Fragments and granules dominated their apparent characteristics, and showed spatial classifications in different areas. The abundance of fragment, granule and foam showed a similar unimodal trend, as they peaked when the Kuroshio fraction was 0.1, implying the effect of Kuroshio intrusion was a combination of the dilution and biogeochemical influence. The polymer types of microplastics, dominated by polypropylene (PP), polyethylene (PE), polyester (PES), polymethacrylate (PMA) and phenoxy resin (PR), showed complicated compositions in the northern SCS, and Kuroshio intrusion was not the dominant influencing factor. Further study is needed to discover the comprehensive effect of Kuroshio intrusion on the fate of microplastics and is expected for the whole WBC system.

Bioprocess-Inspired Room-Temperature Synthesis of Enamel-like Fluorapatite/Polymer Nanocomposites Controlled by Magnesium Ions.

Tooth enamel is composed of arrayed fluorapatite (FAP) or hydroxyapatite nanorods modified with Mg-rich amorphous layers. Although it is known that Mg2+ plays an important role in the formation of enamel, there is limited research on the regulatory role of Mg2+ in the synthesis of enamel-like materials. Therefore, we focus on the regulatory behavior of Mg2+ in the fabrication of biomimetic mineralized enamel-like structural materials. In the present study, we adopt a bioprocess-inspired room-temperature mineralization technique to synthesize a multilayered array of enamel-like columnar FAP/polymer nanocomposites controlled by Mg2+ (FPN-M). The results reveal that the presence of Mg2+ induced the compaction of the array and the formation of a unique Mg-rich amorphous-reinforced architecture. Therefore, the FPN-M array exhibits excellent mechanical properties. The hardness (2.42 ± 0.01 GPa) and Young's modulus (81.5 ± 0.6 GPa) of the as-prepared FPN-M array are comparable to those of its biological counterparts; furthermore, the enamel-like FPN-M array is translucent. The hardness and Young's modulus of the synthetic array of FAP/polymer nanocomposites without Mg2+ control (FPN) are 0.51 ± 0.04 and 43.5 ± 1.6 GPa, respectively. The present study demonstrates a reliable bioprocess-inspired room-temperature fabrication technique for the development of advanced high-performance composite materials.

Rapid collagen-directed mineralization of calcium fluoride nanocrystals with periodically patterned nanostructures.

Collagen fibrils present periodic structures, which provide space for intrafibrillar growth of oriented hydroxyapatite nanocrystals in bone and contribute to the good mechanical properties of bone. However, there are not many reports focused on bioprocess-inspired synthesis of non-native inorganic materials inside collagen fibrils and detailed forming processes of crystals inside collagen fibrils remain poorly understood. Herein, the rapid intrafibrillar mineralization of calcium fluoride nanocrystals with a periodically patterned nanostructure is demonstrated. The negatively charged calcium fluoride precursor phase infiltrates collagen fibrils through the gap zones creating an intricate periodic mineralization pattern. Later, the nanocrystals initially filling the gap zones only expand gradually into the remaining space within the collagen fibrils. Mineralized tendons with organized calcium fluoride nanocrystals acquire mechanical properties (indentation elastic modulus ∼25.1 GPa and hardness ∼1.5 GPa) comparable or even superior to those of native human dentin and lamellar bone. Understanding the mineral growth processes in collagen may facilitate the development of tissue engineering and repairing.

Anatomical structure, and expression of CCL4 and CCL13-like during the development of maxillary barbel in Paramisgurnus dabryanus.

Paramisgurnus dabryanus is one of the most economically important fishes in China. Barbels are an essential sensory organ for the food-seeking ability of teleost fish. However, the anatomical structure of the maxillary barbels of P. dabryanus and the molecular basis of their development are unknown. We investigated the anatomical structure of the barbel, and gene expression patterns of two chemokine C-C motif ligands: CCL4 and CCL13-like during the maxillary barbel development using Masson Trichrome staining, light and electron microscopy, and qPCR. Anatomically, the maxillary barbel of P. dabryanus contains taste buds, melanophores, collagen fibers, connective tissue, smooth muscles, nerve bundles, and blood vessels, but does not have skeletal muscles or a skeleton rod. The expression of CCL4 and CCL13-like was weak or non-existent in the early phases of development, but high at the last two studied time-points: 192- and 216-h post-hatching. Results indicated that CCL4 and CCL13-like were related to the development of the maxillary barbel.

The development of an in vitro assay to screen lipid based nanoparticles for siRNA delivery.

In order to rapidly screen and select lead candidates for in vivo evaluation of lipid nanoparticles (LNPs) for systemic small interfering RNA (siRNA) delivery, an in vitro assay amenable to high-throughput screening (HTS) is developed. The strategy is to mimic the in vivo experience of LNPs after systemic administration, such as interactions with serum components, exposure to endosomal pH environments, and interactions with endosomal membrane lipids. It is postulated that the amount of siRNA released from LNPs after going through these treatments can be used as a screening tool to rank order the effectiveness of siRNA delivery by lipid nanoparticles in vivo. LNPs were incubated with 50% serum from different species (i.e. mouse, rat, or rhesus) at 37°C. The resulting samples were then reacted with anionic, endosomal-mimicking lipids at different pHs. The amount of siRNA released from LNPs was determined using spectrophotometry employing the fluorescent indicator SYBR Gold. Our results indicated that the amount of siRNA liberated was highly dependent upon the species of serum used and the pH to which it was exposed. LNPs treated with mouse serum showed higher levels of siRNA release, as did those subjected to endosomal pH (6.0), compared to physiological pH. Most interestingly, a good correlation between the amount of siRNA released and the in vivo efficacy was observed. In conclusion, an in vitro siRNA release assay was developed to screen and rank order LNPs for in vivo evaluation.

[The expression of collagen I during mandibular fracture healing with the inferior alveolar nerve mutilated].

OBJECTIVE: To establish a stable mandibular fracture model with inferior alveolar nerve (IAN) mutilated for exploring the IAN influence to the expression of collagen I during mandibular fracture. METHODS: Japanese white rabbits were selected and IAN was liberated. The right was leaven as it is and the left was cut off, then 2 mm x 5 mm fracture model was made, and HE staining and chromotropic acid 2R-bright green staining and in situ hybridization of collagen I mRNA were made to detect mandibular fracture healing and collagen I mRNA expression. RESULTS: Fracture healing was smooth in IAN conserved side, but delayed in the IAN mutilated side. Collagen I in situ hybridization showed that at one week and two weeks after surgery there were obvious differences between the two sides (P < 0.05), but no difference at three weeks after surgery and four weeks (P > 0.05). CONCLUSION: The IAN could regulate mandibular fracture healing, and influence collagen I mRNA earlier expression.

Isolation and identification of oligomers from partial degradation of lime fruit cutin.

Complementary degradative treatments with low-temperature hydrofluoric acid and methanolic potassium hydroxide have been used to investigate the protective biopolymer cutin from Citrus aurantifolia (lime) fruits, augmenting prior enzymatic and chemical strategies to yield a more comprehensive view of its molecular architecture. Analysis of the resulting soluble oligomeric fragments with one- and two-dimensional NMR and MS methods identified a new dimer and three trimeric esters of primary alcohols based on 10,16-dihydroxyhexadecanoic acid and 10-oxo-16-hydroxyhexadecanoic acid units. Whereas only 10-oxo-16-hydroxyhexadecanoic acid units were found in the oligomers from hydrofluoric acid treatments, the dimer and trimer products isolated to date using diverse degradative methods included six of the seven possible stoichiometric ratios of monomer units. A novel glucoside-linked hydroxyfatty acid tetramer was also identified provisionally, suggesting that the cutin biopolymer can be bound covalently to the plant cell wall. Although the current findings suggest that the predominant molecular architecture of this protective polymer in lime fruits involves esters of primary and secondary alcohols based on long-chain hydroxyfatty acids, the possibility of additional cross-linking to enhance structural integrity is underscored by these and related findings of nonstandard cutin molecular architectures.