Natural Organisms Research Articles

Rational Design of Covalent Heptazine Frameworks with Spatially Separated Redox Centers for High-Efficiency Photocatalytic Hydrogen Peroxide Production.

The redox reaction centers in natural organisms conducting oxygenic photosynthesis are well arranged in a physically separated manner to convert sunlight into chemical energy efficiently. Mimicking natural photosynthesis via precisely constructing oxidative and reductive reaction centers within photocatalysts is ideal for enhancing catalytic performances in artificial photosynthesis. In this study, new covalent heptazine frameworks (CHFs) with spatially separated redox centers are rationally designed for photocatalytic production of H2 O2 from water and oxygen without using any sacrificial agents. Both experimental and computational investigations indicate that the two-electron oxygen reduction reaction occurs on the heptazine moiety, whereas the two-electron water oxidation reaction occurs on the acetylene or diacetylene bond in the CHFs. This unique spatial separation feature is critical for enhancing charge separation and achieving efficient H2 O2 production. Meanwhile, the measured exciton binding energy of the diacetylene-containing polymer is merely 24 meV. Under simulated solar irradiation, the rationally designed CHFs can achieve a solar-to-chemical conversion efficiency of 0.78%, surpassing previously reported photocatalytic materials. This study establishes a molecular engineering approach to construct periodically arranged and spatially separated redox centers in single-component polymer photocatalysts, representing a hallmark to create more exciting polymer structures for photocatalysis moving forward.

Reconfigurable assembly of colloidal motors towards interactive soft materials and systems

Due to the highly flexible reconfiguration of swarms, collective behaviors have provided various natural organisms with a powerful adaptivity to the complex environment. To mimic these natural systems and construct artificial intelligent soft materials, self-propelled colloidal motors that can convert diverse forms of energy into swimming-like movement in fluids afford an ideal model system at the micro-/nanoscales. Through the coupling of local gradient fields, colloidal motors driven by chemical reactions or externally physical fields can assembly into swarms with adaptivity. Here, we summarize the progress on reconfigurable assembly of colloidal motors which is driven and modulated by chemical reactions and external fields (e.g., light, ultrasonic, electric, and magnetic fields). The adaptive reconfiguration behaviors and the corresponding mechanisms are discussed in detail. The future directions and challenges are also addressed for developing colloidal motor-based interactive soft matter materials and systems with adaptation and interactive functions comparable to that of natural systems.

Hive‐Inspired Multifunctional Wood‐Nanotechnology‐Derived Membranes with a Double‐Layer Conductive Network Structure for Flexible Electronics

AbstractNext‐generation flexible electronics must achieve multifunctionality, environmental friendliness and antibacterial activity. Accordingly, organisms in nature are interconnected. Inspired by the honeycomb multilayer porous structure, a wood‐nanotechnology‐derived flexible membrane circuit is created to meet the abovementioned requirements. The flexible wood (FW) matrix is made of natural balsa wood that underwent a simple top‐down chemical treatment. The multiwalled carbon nanotube (MWCNT) acts as a “bridge” between the FW matrix with a porous array structure and the active material (silver nanoparticles (Ag NPs) and poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Due to the three‐dimensional porous microstructure and highly conductive surface inherited by the wood‐nanotechnology‐derived flexible membrane (FW/MWCNT/Ag/PEDOT:PSS), it shows a high area capacitance (266.7 mF cm−2 at 20 mV s−1) and a good long‐term cycling stability 84.3% capacitance retention after 5000 cycles at 5 mA cm−2 when used as a supercapacitor electrode. In addition, it shows an excellent specific electromagnetic shielding efficiency (up to 970 dB cm2 g−1), proving its application potential in the field of electromagnetic shielding. Because of the biocidal property of Ag NPs, the FW/MWCNT/Ag/PEDOT:PSS shows a remarkable antibacterial effect on Escherichia coli and Staphylococcus aureus. This strategy provides a new opportunity for researchers to design biomass‐based integrated electronic materials.

Recent Advances of Biomedical Materials for Prevention of Post-ESD Esophageal Stricture.

Esophageal stricture commonly occurs in patients that have suffered from endoscopic submucosal dissection (ESD), and it makes swallowing difficult for patients, significantly reducing their life qualities. So far, the prevention strategies applied in clinical practice for post-ESD esophageal stricture usually bring various inevitable complications, which drastically counteract their effectiveness. Nowadays, with the widespread investigation and application of biomedical materials, lots of novel approaches have been devised in terms of the prevention of esophageal stricture. Biomedical polymers and biomedical-derived materials are the most used biomedical materials to prevent esophageal stricture after ESD. Both of biomedical polymers and biomedical-derived materials possess great physicochemical properties such as biocompatibility and biodegradability. Moreover, some biomedical polymers can be used as scaffolds to promote cell growth, and biomedical-derived materials have biological functions similar to natural organisms, so they are important in tissue engineering. In this review, we have summarized the current approaches for preventing esophageal stricture and put emphasis on the discussion of the roles biomedical polymers and biomedical-derived materials acted in esophageal stricture prevention. Meanwhile, we proposed several potential methods that may be highly rational and feasible in esophageal stricture prevention based on other researches associated with biomedical materials. This review is expected to offer a significant inspiration from biomedical materials to explore more effective, safer, and more economical strategies to manage post-ESD esophageal stricture.

In Silico Taste – Toxicological Study of Chlorfenvinphos, Dichlofluanid, Fonofos, or Methacrifos Partial Degradation Products

Toxicity is important factor to human and environment and can be tested in lab and by computerized models. ProTox-II is in Silico method to assess safety of chemicals to minimize risk health threating to human and other living organisms in nature. Taste of material is another character can be calculated in Silico model like virtualtaste. Here, first attempt of using two computerized methods and hypothetical partial degradation products of four toxics materials used to control agricultural productivity was carried out to predicate taste and toxicity characters. LD50, Toxicity Class, organ and end point toxicities, Tox21-Nuclear receptor signaling and stress response pathways of Chlorfenvinphos, Dichlofluanid, Fonofos, and Methacrifos with their hypothetical degradation products were calculated. Hypothetical degradation products were a results of (C-C, C-O, C-N, C-S, C-P, P-O, P-S, or N-S) bond breakage. The hypothesized degradation chemicals showed that most of them were with sour taste and their toxicity were less class compared to the parent compound but not to non-toxic material (Class 6, LD50 more than 5000 mg/kg). Also, they were structurally toxics and could be interact with molecular cellular target resulting than parent compound if they presented in required concentration.

Assessment of Tilapia–Freshwater Prawn Co-Culture Schemes in Tanks and Lake-Based Cages for Increased Farm Production

The technical viability of tilapia (I-ExCEL strain Nile or red) and giant freshwater prawn (GFP) co-culture in cages-within-tanks was evaluated while appropriate feeding protocols for tilapia-GFP co-culture in cages in a eutrophic lake were determined. Specifically, production parameters in all test species grown for five months in tank co-culture (where only tilapias were fed) were compared, while the best feeding protocol from among the following treatments: (a) Tfed—fed tilapias; (b) GFPfed—fed prawns and (c) T-GFPfed—both species fed, were defined. I-ExCEL Nile tilapias grew faster in tank co-culture whether reared singly or otherwise. However, red tilapia-GFP tank co-culture gave the best results considering key production traits in all test species (red tilapia —2.52%/day specific growth rate or SGR, 83.3% survival; GFP—1.17%/day SGR, 72.85% survival). Lake-based co-culture was technically feasible at stocking densities of 12.5/m2 for tilapia and 2.4 to 4/m2 for prawns even when only tilapias were fed; prawns grew to desired marketable sizes by thriving mainly on detritus and natural food organisms in the lake. However, further refinements can still be made to optimise the co-culture schemes to make them more sustainable and provide artisanal fish farmers options in increasing farm yields through multi-species aquaculture.

Progress on Biomimetic Mineralization and Materials for Hard Tissue Regeneration.

Biomineralization is a process in which natural organisms regulate the crystal growth of inorganic minerals, resulting in hierarchical structured biominerals with excellent properties. Typical biominerals in the human body are the bones and teeth, and damage to these hard tissues directly affect our daily lives. The repair of bones and teeth in a biomimetic way, either by using a biomimetic mineralization strategy or biomimetic materials, is the key for hard tissue regeneration. In this review, we briefly introduce the structure of bone and tooth, and highlight the fundamental role of collagen mineralization in tissue repair. The recent progress on intra-/extrafibrillar collagen mineralization by a biomimetic strategy or materials is presented, and their potential for tissue regeneration is discussed. Then, recent achievements on bone and tooth repair are summarized, and these works are discussed in the view of materials science and biological science, providing a broader vision for the future research of hard tissue repair techniques. Lastly, recent progress on hard tissue regeneration is concluded, and existing problems and future directions are prospected.

Controlling Directional Liquid Transport on Dual Cylindrical Fibers with Oriented Open‐Wedges

AbstractDirectional liquid transport (DLT) on fibrous systems has been widely used in both natural organisms and practical applications as an important mass transfer strategy. So far, DLTs on fibers are heavily dependent on the conical structure that enables generating the Laplace pressure difference. For the cylindrical fibers, liquid can only transport evenly along both directions of the axis driven by the capillary forces between fibers, which however hardly proceeds directionally in a controllable way. Here, the authors revealed that the dual cylindrical hairs bear the ability of DLT, which is attributable to the wet‐rebuilt open‐wedged scales. Capillary forces along wedge corners facilitate the liquid transport in the against‐scale direction, while the pinning effect at the sharp edges of open‐wedges works cooperatively with the anisotropic retention force imparted by the ratchet structures to inhibit liquid spreading in the with‐scale direction. Consequently, liquid prefers to transport in the against‐scale direction on dual cylindrical hairs. Drawing inspirations, the authors develop the conceptual‐model of dual cylindrical fibers that is capable of DLT, and moreover the DLT with different rectification ratios can be well‐controlled depending on the opening angle of wedges. The result offers new insights for manipulating liquid using cylindrical fibrous systems.

Development of robust amphiphobic hierarchical structure on polymer substrate by thermal imprinting and sputter etching

Amphiphobic surfaces are found in many natural organisms for protection from external contamination because they can repel both water and oil. The development of an amphiphobic surface is based on the construction of hierarchical structures and chemical modification. In this study, thermal imprinting and sputter etching were conducted to create a micropillar array and nano-protrusions to form a hierarchical structure. Different hierarchical structures were developed by using different nickel stamps and upon varying the etching time. These structures were modified using an environment-friendly drysurf (G993G3, Harves) solution through a spraying method. The surface presented high repellency toward various liquid droplets with surface tensions ranging from 72 to 22 mN m −1 , with contact angles of 158° for water and 120° for hexadecane. The surface showed good self-cleaning performance without any traces of water droplets or glass bead particles. In addition, various tests including sand abrasion , bending, and immersion tests were conducted to evaluate the mechanical and chemical robustness of the hierarchical structure, which exhibited good performance. Hierarchical structures with these excellent properties are expected to be widely applied in surface waterproofing, antifouling, and self-cleaning treatments. • Micropillars with appropriate size are required to create hierarchical structure. • Net-like nanoprotrusions are fabricated on micropillars by sputter etching. • Hierarchical micro/nanostructure shows better amphiphobicity than micropillars. • The amphiphobic surface presents good chemical stability and mechanical robustness. • The amphiphobic surface can be applied as antifouling and self-cleaning materials.

ICMCTF 2021 – Preface

Amphiphobic surfaces are found in many natural organisms for protection from external contamination because they can repel both water and oil. The development of an amphiphobic surface is based on the construction of hierarchical structures and chemical modification. In this study, thermal imprinting and sputter etching were conducted to create a micropillar array and nano-protrusions to form a hierarchical structure. Different hierarchical structures were developed by using different nickel stamps and upon varying the etching time. These structures were modified using an environment-friendly drysurf (G993G3, Harves) solution through a spraying method. The surface presented high repellency toward various liquid droplets with surface tensions ranging from 72 to 22 mN m−1, with contact angles of 158° for water and 120° for hexadecane. The surface showed good self-cleaning performance without any traces of water droplets or glass bead particles. In addition, various tests including sand abrasion, bending, and immersion tests were conducted to evaluate the mechanical and chemical robustness of the hierarchical structure, which exhibited good performance. Hierarchical structures with these excellent properties are expected to be widely applied in surface waterproofing, antifouling, and self-cleaning treatments.

EFFECT OF SUGARCANE BAGASSE AND SUPPLEMENTARY FEED ON EGG AND SPERM QUALITY OF CATFISH, HETEROPNEUSTES FOSSILIS (BLOCH)

In modern aquaculture, feed is one of the major components affecting the cost of production. In most traditional aquaculture practices, herbivorous or omnivorous species have been preferred as they feed on natural food organisms, the growth of which can be enhanced through fertilization and water management (Pillay, 2001). But carnivorous species generally need a high protein diet and are therefore, considered to be more expensive to produce, even though the costs will depend largely on local availability and price of the required feed stuffs. To compensate the feeding costs, most carnivorous species command higher market prices. Such species generally have greater export markets and therefore, attract substantial investments. In the present study, investigations were carried out to evaluate the egg and sperm quality of the catfish, Heteropneustes fossilis in sugarcane bagasse substrate medium. This species was selected due to its ability to adapt in fresh and brackish waters with very low oxygen and could grow under generally poor environmental conditions, make these fishes extremely valuable for small and large scale rural fish farming (Pillay, 2001). Substrate-based farming practices are considered viable low-cost technologies as they help in sustainable aquaculture production (Dharmaraj et al., 2002). Sugarcane bagasse is the fibrous residue remaining after sugarcane stalks are crushed to extract their juice, generated in large quantities and is currently used as a renewable resource in the manufacture of pulp and paper products and building materials.

Identification of sequence motifs in Lhcx proteins that confer qE-based photoprotection in the diatom Phaeodactylum tricornutum.

Photosynthetic organisms in nature often experience light fluctuations. While low light conditions limit the energy uptake by algae, light absorption exceeding the maximal rate of photosynthesis may go along with enhanced formation of potentially toxic reactive oxygen species. To preempt high light-induced photodamage, photosynthetic organisms evolved numerous photoprotective mechanisms. Among these, energy-dependent fluorescence quenching (qE) provides a rapid mechanism to dissipate thermally the excessively absorbed energy. Diatoms thrive in all aquatic environments and thus belong to the most important primary producers on earth. qE in diatoms is provided by a concerted action of Lhcx proteins and the xanthophyll cycle pigment diatoxanthin. While the exact Lhcx activation mechanism of diatom qE is unknown, two lumen-exposed acidic amino acids within Lhcx proteins were proposed to function as regulatory switches upon light-induced lumenal acidification. By introducing a modified Lhcx1 lacking these amino acids into a Phaeodactylum tricornutum Lhcx1-null qE knockout line, we demonstrate that qE is unaffected by these two amino acids. Based on sequence comparisons with Lhcx4, being incapable of providing qE, we perform domain swap experiments of Lhcx4 with Lhcx1 and identify two peptide motifs involved in conferring qE. Within one of these motifs, we identify a tryptophan residue with a major influence on qE establishment. This tryptophan residue is located in close proximity to the diadinoxanthin/diatoxanthin-binding site based on the recently revealed diatom Lhc crystal structure. Our findings provide a structural explanation for the intimate link of Lhcx and diatoxanthin in providing qE in diatoms.

Tracking of realistic nanoplastics in complicated matrices by iridium element labeling and inductively coupled plasma mass spectroscopy

Herein, we proposed a protocol to track realistic nanoplastics (NPs) by labeling them with an iridium-containing organic molecular agent (denoted as Ir) followed by inductively coupled plasma mass spectroscopy detection, as exemplified by polyethylene terephthalate (PET) NPs prepared from water bottles. The Ir showed satisfactory labeling stability in typical environmental and biological matrices. After 3d’s incubation, the leaching ratios were less than 3% in water, phosphate buffered saline, sea water, cell culture medium, artificial gastric juice, artificial intestinal fluid, sediment resuspension, and around 5% in fetal bovine serum. On this basis, in vivo distribution of PET NPs in mice was analyzed. The intravenously injected NPs widely distributed in liver, spleen, lung and kidney. Comparatively, NPs could hardly be detected in these organs after intragastric administration, suggesting that they could not penetrate the intestinal barriers. The temporal and spatial distribution of the NPs in an intertidal zone sediment resuspension model was also investigated. The NPs mostly deposited at the overlying deposit, implying the absorption-driven sinking behavior of NPs with natural organic matters. This work provided an effective way to quantitatively track realistic NPs, which could promote the understanding of the fate and effect of NPs in natural environments and organisms.

Cassie State Stability and Gas Restoration Capability of Superhydrophobic Surfaces with Truncated Cone-Shaped Pillars.

The gas layer stability on superhydrophobic surfaces and gas restoration on the immersed superhydrophobic surfaces have been great challenges for their practical applications in recent years. Inspired by the naturally existing mushroom-like super-repellent superhydrophobic patterns, we choose superhydrophobic surfaces with truncated cone-shaped pillars as our research objects to tackle such challenges by tuning their geometrical parameters. We perform molecular dynamics simulations to investigate the Cassie-Wenzel transition under external pressure and the Wenzel-Cassie transition due to underwater spreading of compressed bubbles. Theories based on the Young-Laplace equation and total free-energy variation are developed to explore the influence of geometrical parameters of pillars on the pressure resistance and underwater gas restoration, which is in good agreement with simulation results. These simulation results and theoretical analysis suggest that cork-shaped pillars, analogous to the surface structures of natural organisms like springtails and Salvinia leaves, can be super-repellent to the liquid and favorable for the gas spreading process. Our study provides theoretical guidance for the design of superhydrophobic surfaces with both Cassie state stability and gas restoration capability.

A perspective on insect-microbe holobionts facing thermal fluctuations in a climate-change context.

Temperature influences the ecology and evolution of insects and their symbionts by impacting each partner independently and their interactions, considering the holobiont as a primary unit of selection. There are sound data about the responses of these partnerships to constant temperatures and sporadic thermal stress (mostly heat shock). However, the current understanding of the thermal ecology of insect-microbe holobionts remains patchy because the complex thermal fluctuations (at different spatial and temporal scales) experienced by these organisms in nature have often been overlooked experimentally. This may drastically constrain our ability to predict the fate of mutualistic interactions under climate change, which will alter both mean temperatures and thermal variability. Here, we tackle down these issues by focusing on the effects of temperature fluctuations on the evolutionary ecology of insect-microbe holobionts. We propose potentially worth-investigating research avenues to (i) evaluate the relevance of theoretical concepts used to predict the biological impacts of temperature fluctuations when applied to holobionts; (ii) acknowledge the plastic (behavioural thermoregulation, physiological acclimation) and genetic responses (evolution) expressed by holobionts in fluctuating thermal environments; and (iii) explore the potential impacts of previously unconsidered patterns of temperature fluctuations on the outcomes and the dynamic of these insect-microbe associations.

Mimicking nature to control bio-material surface wetting and adhesion

ABSTRACT Nature has developed unique strategies to refine and optimise structural performance. Using surfaces designed at multiple length scales, from micro to nano levels, combined with complex chemistries, different natural organisms can exhibit similar wetting but different adhesion to liquids under specific environments. These biological surfaces have inspired researchers to develop new approaches to control surface wetting and liquid behaviour via surface adhesion. Here we review natural strategies to control the interaction of liquids with solid surfaces and the efforts to implement these strategies in synthetic materials designed to work in either atmospheric or underwater environment. Particular attention is paid to droplet behaviour on the special-adhesion surfaces in nature and artificial smart surfaces. We highlight recent progress, identify the common threads, and discuss the fundamental differences in a way that can help formulate rational approaches towards surface engineering, and identify current challenges as well as future directions for the field.

Femtosecond Laser Regulated Ultrafast Growth of Mushroom-Like Architecture for Oil Repellency and Manipulation.

Natural organisms can create various microstructures via a spontaneous growth mode. In contrast, artificial protruding microstructures are constructed by subtractive methods that waste materials and time or by additive methods that require additional materials. Here, we report a facile and straightforward strategy for a laser-induced self-growing mushroom-like microstructure on a flat surface. By simply controlling the localized femtosecond laser heating and ablation on the poly(ethylene terephthalate) tape/heat-shrinkable polystyrene bilayer surface, it is discovered that a mushroom-like architecture can spontaneously and rapidly grow out from the original surface within 0.36 s. The dimension of the re-entrant micropillar array (cap diameter, pillar spacing, and height) can be accurately controlled through the intentional control of laser scanning. Followed by a fluorination and spray coating, the obtained surface can realize the repellency and manipulation of oil droplets. This work provides new opportunities in the fields of microfabrication, microfluidics, microreactor engineering, and wearable antifouling electronics.

Recombinant and endogenous ways to produce methylated phospholipids in Escherichia coli

Escherichia coli is the daily workhorse in molecular biology research labs and an important platform microorganism in white biotechnology. Its cytoplasmic membrane is primarily composed of the phospholipids phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL). As in most other bacteria, the typical eukaryotic phosphatidylcholine (PC) is not a regular component of the E. coli membrane. PC is known to act as a substrate in various metabolic or catabolic reactions, to affect protein folding and membrane insertion, and to activate proteins that originate from eukaryotic environments. Options to manipulate the E. coli membrane to include non-native lipids such as PC might make it an even more powerful and versatile tool for biotechnology and protein biochemistry. This article outlines different strategies how E. coli can be engineered to produce PC and other methylated PE derivatives. Several of these approaches rely on the ectopic expression of genes from natural PC-producing organisms. These include PC synthases, lysolipid acyltransferases, and several phospholipid N-methyltransferases with diverse substrate and product preferences. In addition, we show that E. coli has the capacity to produce PC by its own enzyme repertoire provided that appropriate precursors are supplied. Screening of the E. coli Keio knockout collection revealed the lysophospholipid transporter LplT to be responsible for the uptake of lyso-PC, which is then further acylated to PC by the acyltransferase-acyl carrier protein synthetase Aas. Overall, our study shows that the membrane composition of the most routinely used model bacterium can readily be tailored on demand.Key points• Escherichia coli can be engineered to produce non-native methylated PE derivatives.• These lipids can be produced by foreign and endogenous proteins.• Modification of E. coli membrane offers potential for biotechnology and research.Graphical abstract

Modulation of circadian clock by crude drug extracts used in Japanese Kampo medicine

Circadian rhythm is an approximately 24 h endogenous biological rhythm. Chronic disruption of the circadian clock leads to an increased risk of diabetes, cardiovascular disease, and cancer. Hence, it is important to develop circadian clock modulators. Natural organisms are a good source of several medicines currently in use. Crude drugs used in Japanese traditional Kampo medicine or folk medicines are an excellent source for drug discovery. Furthermore, identifying new functions for existing drugs, known as the drug repositioning approach, is a popular and powerful tool. In this study, we screened 137 crude drug extracts to act as circadian clock modulators in human U2OS cells stably expressing the clock reporter Bmal1-dLuc, and approximately 12% of these modulated the circadian rhythm. We further examined the effects of several crude drugs in Rat-1 fibroblasts stably expressing Per2-luc, explant culture of lung from Per2::Luciferase knockin mice, and zebrafish larvae in vivo. Notably, more than half of the major ingredients of these crude drugs were reported to target AKT and its relevant signaling pathways. As expected, analysis of the major ingredients targeting AKT signaling confirmed the circadian clock-modulating effects. Furthermore, activator and inhibitor of AKT, and triple knockdown of AKT isoforms by siRNA also modulated the circadian rhythm. This study, by employing the drug repositioning approach, shows that Kampo medicines are a useful source for the identification of underlying mechanisms of circadian clock modulators and could potentially be used in the treatment of circadian clock disruption.

Intelligent, biomimetic, color-tunable, light-emitting artificial skin with memory function

The ability to combine the color-tunability capability of natural organisms with a memory function in a single device is highly desired and holds promise for potential applications such as intelligent artificial skin and human-machine interfaces. In this work, we propose a universal strategy to realize color-tunable skin with the compound function of memory by ingeniously integrating a memristor interface into a flexible quantum-dot light-emitting device. The devices developed using this strategy have multiple responses to electrical and light stimulations and can easily change their color over a wide range from red to green. Moreover, these color-tunable devices can mimic the unique function of “once bitten, twice shy” to enhance self-protection, and their color tunability is consistent with the memory-forgetting curve proposed by psychologists.