Pretreatment Medium Research Articles

Effects of thermal pretreatment and puffing medium variously modify the microstructure and quality of crisps obtained from two banana varieties

Fat-free crisp food products are garnering more attention from modern consumers. Hot air combined explosion puffing is one processing method that can produce a crisp food snack. Therefore, the influences of thermal pretreatment, banana variety, puffing medium, and puffing temperature upon the microstructural changes, drying time, specific energy consumption (SEC), and banana crisp qualities were studied. The banana slices, Namwa (NW) and Homtong (HT) varieties, were blanched with hot water (HW) then hot air-dried at 90 °C and combined with explosion puffing with either superheated steam (SS-puffing) or hot air (HA-puffing) from 170 to 190 °C for 2 min. The experimental results showed a stronger cellular structure and lower enzymatic activities for NW samples compared to the HT samples. This led to a harder texture, longer total drying time, and less browning for NW crisps. The cellular structure of HT was more disrupted than NW after HW pretreatment. Such modified structure characteristics caused a decrease in volume ratio and lower crispiness for HT products, whereas the NW crisp had increasing volume ratio and higher crispiness relative to the non-blanched crisps. Even though the blanching pretreatments retarded browning and improved color uniformity for both banana varieties, the process increased the total drying time and the SEC values of the drying process. By applying SS-puffing and raising the puffing temperature of blanched NW samples, higher puffed volume and crispier texture products were obtained. Additionally, the total drying time and the SEC value were also reduced. The SS-puffing also led to browner products for both NW and HT samples. Finally, the overall preference score was markedly higher for blanched NW crisp compared to blanched HT crisp; however, neither score exceeded that of commercial products.

The ERβ-cAMP signaling pathway regulates estradiol-induced ovine oocyte meiotic arrest

Although 17β-estradiol (E2) and its receptors (ERs) are reported to play important roles in regulating oocyte maturation, the specific mechanism remains unclear. First, we performed immunohistochemistry analyses to determine the expression of the ERα and ERβ proteins in ovine ovarian tissue. Second, E2 (0.5 ng/mL and 1 μg/mL) were added to pre-IVM medium for 0 h, 1 h and 2 h. The effects of E2 (0.5 ng/mL and 1 μg/mL) on cyclic adenosine monophosphate (cAMP) level in cumulus-oocyte complexes (COCs) and on oocyte meiotic progression were evaluated by ELISA and DAPI staining respectively. Third, the effects of E2 on the gene and protein expression of ERα and ERβ in COCs were investigated by Western blotting and real-time PCR. Afterward, ERβ and cAMP regulators were added to the 2-h pretreatment medium with or without E2 (0.5 ng/mL) to explore the possible interactions among E2, cAMP and ERβ. The results showed that both ERα and ERβ proteins were expressed in ovine cumulus layers and oocytes. E2 significantly increased intra-COC cAMP levels, maintained oocyte meiotic arrest, and promoted ERβ transcript and protein expression. E2 treatment increased the cAMP concentration, which was enhanced by ERβ agonist treatment and remarkably attenuated by ERβ inhibitor treatment. Forskolin plus IBMX treatment increased ERβ protein expression in COCs (P < 0.05), and this was attenuated by Rp-cAMP treatment. In conclusion, E2 (0.5 ng/mL) increased intra-COC cAMP levels by promoting ERβ expression, thereby maintaining oocyte meiotic arrest. cAMP in COCs has a positive feedback effect on ERβ expression, which provides a novel explanation for the positive role of E2 in regulating ovine follicle development and oocyte maturation.

Efficient separation and production of high-quality rubber, lignin nanoparticles and fermentable sugars from Eucommia ulmoides pericarp via deep eutectic solvent pretreatment

The natural barriers of lignocellulose hinder the separation of Eucommia ulmoides rubber (EUR) from Eucommia ulmoides pericarp (EUP), whereas traditional separation methods normally lead to the waste of Eucommia ulmoides lignocellulose resource and environmental pollution. In this study, an acidic deep eutectic solvent composed of lactic acid and ZnCl2 was developed as a pretreatment medium to reduce the separation barriers of EUR while producing lignin nanoparticles and fermentable sugars. Results showed that DES pretreatment could accelerate the extraction efficiency (91.0 %) and purity (>99 %) of EUR and maintain its chemical structure compared to the traditional alkaline and mechanical methods. Meanwhile, the regenerated nano-lignin showed excellent antioxidant activity (IC50 = 46.3 μg/mL) comparable to commercial antioxidant BHA. Besides, the enzymatic hydrolysis efficiency of EUP with DES pretreatment was significantly enhanced about 9 times than the control groups. Overall, the acidic DES pretreatment could be considered a promising pretreatment method for separation of high-quality EUR and valorization of lignocellulosic components.

Microwave-assisted alkali pre-treatment medium for fractionation of rice straw and catalytic conversion to value-added 5-hydroxymethyl furfural and lignin production

In the current study, the use of microwave-assisted sodium hydroxide medium (MWSH) for pre-treatment and saccharification of rice straw to obtain sugar syrup for the production of 5-hydroxymethyl furfural (5-HMF) was investigated. The optimization of the MWSH pre-treatment was carried out using central composite methodology, resulting in a maximum reducing sugar yield of 350 mg/g of treated rice straw (TRS) and a glucose yield of 255 mg/g of TRS under the conditions of a microwave power of 681 W, a NaOH concentration of 0.54 M, and a pre-treatment time of 3 min. Additionally, the microwave assisted transformation of sugar syrup with titanium magnetic silica nanoparticle as catalyst, producing 41.1 % yield of 5-HMF from the sugar syrup after 30 min microwave irradiation at 120 °C with catalyst loading of 2.0:200 (w/v)). The structural characterization of the lignin was analysed using 1H NMR techniques, and the surface carbon (C1s spectra) and oxygen (O1s spectra) composition changes of the rice straw during pre-treatment were analysed using X-ray photoelectron spectroscopy. The rice straw based bio-refinery process which contains MWSH pretreatment followed by dehydration of sugars achieved high efficiency of 5-HMF production.

Sustainable production of 2-phenylethanol from agro-industrial wastes by metabolically engineered Bacillus licheniformis

2-Phenylethanol (2-PE) is a kind of bulk flavor and fragrance, widely applied in food, fragrance, and cosmetic industries. In this work, a sustainable platform for 2-PE biosynthesis was developed by engineering Bacillus licheniformis using agro-industrial wastes as feedstocks. Firstly, the endogenous sucrose catabolism pathway of B. licheniformis was replaced by introducing CscB from Escherichia coli W and SucP from Bifdobacterium adolescentis. The 2-PE titer and yield of the resulting strain PE24 increased to 6.52 ± 0.20 g/L and 0.16 g/g sucrose, respectively, which increased by 16% compared to the control strain PE23 using 40 g/L sucrose as the carbon source. Subsequently, the effects of molasses and crude glycerol as the feedstocks on 2-PE production were investigated. By optimizing the molasses pretreatment methods and medium components, the 2-PE production was increased from 2.21 g/L to 5.74 g/L using 50 g/L pretreated molasses, 15 g/L crude glycerol, and 7 g/L corn steep liquor powder as the raw materials. Finally, we characterized the PE24 strain by fed-batch fermentation in 5-L fermenter and achieved a titer of 6.43 g/L of 2-PE, representing the highest level of 2-PE production. This study provided a cost-effective process for 2-PE sustainable biosynthesis.

Nutritional and Chemical Composition of Jackfruit Rind Flour

Background: Jackfruit (Artocarpus heterophyllus Lam.) belongs to the family Moraceae.Two cultivars of jackfruit are popular in Kerala being “Koozha” and “Varikka” The rind of jackfruit is mostly thrown away or given to cattle. This issue has been addressed by processing the rind into flour and ascertaining its nutritional and chemical composition. Methods: Mature jackfruits-Raw and ripe (cv varikka and koozha) with optimum maturity indices were selected from the instructional farm, College of Agriculture, Vellayani. They were cleaned, cut and immersed in pre treatment media and subjected to drying. The dried product was milled and packed in laminated pouches. They were subjected to quality analysis using standard procedures. Result: The nutrient analysis of jackfruit rind flour showed significant differences among raw and ripened varikka and koozha rind flours. Raw Koozha jackfruit rind flour showed higher content of crude fiber (18 g/ 100 g) and dietary fiber (13.56 g/ 100 g). It had low content of carbohydrate (29 g/100 g) and fat (1.84 g/10 0 g). The chemical composition of raw koozha jackfruit rind flour had higher tannins (0.088 g/100 g). It also had higher content of polyphenols (2 g/100 g) that could be responsible for the enzymatic browning of rinds and had lower peroxide value (0.5 g/100 g), which could be the reason for better keeping quality of this rind type. Pectin content was found to be higher (27.5 g/100 g) in ripe varikka jackfruit rind flour.

Investigation of the hydrogen embrittlement susceptibility of steel components during thin-film hot-dip galvanizing

Abstract With regard to the application of thin-film hot-dip galvanizing to a welded steel tube structure in vehicle construction, several test series were carried out to investigate the potential for hydrogen embrittlement caused by the pretreatment media used in the galvanizing process. Here, C-ring specimens were produced from the materials E355 and C75 in different tempering states, treated in a hydrochloric acid-based operational pickle, and then tested under constant strain rate or constant load. The results show that under the investigated pickling conditions, no hydrogen-induced embrittlement effect occurs up to a hardness of 470 HV in the case of material E355 and 500 HV in the case of material C75. Only in the case of 550 HV and 600 HV, both for C75, was a tendency to embrittlement observed; this effect was more pronounced after treatment with the freshly prepared pickle than in the operating pickles. The two test methods used showed consistent results.

Reducing the Glucose Level in Pre-treatment Solution Improves Post-thaw Boar Sperm Quality.

Frozen–thawed boar sperm was not widely used in pig artificial insemination as the sperm quality was damaged by biochemical and physical modifications during the cryopreservation process. The aim of this study was to investigate whether reduction of the glucose level in diluted medium could protect the post-thaw boar sperm or not. Boar sperm was diluted with the pre-treatment medium with different doses of glucose (153, 122.4, 91.8, 61.2, 30.6, and 0 mM) during the cooling process. The sperm motility patterns and glycolysis were evaluated during the cooling process. Meanwhile, the post-thaw sperm quality, ATP level, mitochondrial function as well as apoptosis were also measured. It was observed that 153 mM glucose treatment showed the highest glycolysis in boar sperm as the activities of hexokinase, fructose-bisphosphate aldolase A, and lactate dehydrogenase are the highest as well as the lactate level. Reduction of the glucose level from 153 to 30.6 mM suppressed sperm glycolysis. In addition, treatment with 153 mM glucose made the sperm demonstrate a circle-like movement along with a high value of curvilinear velocity and amplitude of the lateral head, while decreasing the glucose level reduced those patterns in the cooling process. Moreover, reduction of the glucose level also significantly increased the post-thaw sperm's total motility, progressive motility, straight-linear velocity, membrane integrity, and acrosome integrity. The treatment with 30.6 mM glucose showed the highest value among the treatments. Furthermore, the post-thaw sperm's succinate dehydrogenase activity, malate dehydrogenase activity, mitochondrial membrane potential as well as ATP level were increased by reducing the glucose level from 153 to 30.6 mM. Interestingly, the treatment with 30.6 mM glucose showed the lowest apoptosis of post-thaw sperm among the treatments. Those observations suggest that reduction of the glucose level in diluted medium increased the post-thaw boar sperm quality via decreasing the glycolytic metabolism. These findings provide novel insights that reduction of boar sperm activity via decreasing sperm glycolysis during the cooling process helps to improve the post-thaw sperm quality during cryopreservation.

β-Ketoenamine-linked covalent organic framework absorbent for online micro-solid phase extraction of trace levels bisphenols in plastic samples.

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have exhibited fascinating pretreatment performance as ideal extraction media. Herein, the β-ketoenamine-linked TpPa-1 synthesized by 1,3,5-triformylphloroglucinol and paraphenylenediamine was employed as the absorbent for online micro-solid phase extraction of trace bisphenols combined with high-performance liquid chromatography detection. A series of characterizations indicated that the TpPa-1 possessed large surface areas, high stability, and hydrophobicity. The main experimental parameters affecting the extraction efficiency were optimized in detail. Compared with four commercial sorbents, the TpPa-1 exhibited superior enrichment capacity for extracting bisphenols. Under the optimum conditions, the established method demonstrated a wide linear range and high sensitivity with the limit of detection ranging from 0.05-0.06 μg/L. Furthermore, the developed method was successfully applied to determine bisphenols in plastic samples. Bisphenol A was actually detected in a transparent box with a concentration of 0.31 μg/g, and the recoveries of the four bisphenols in the plastic samples were 80.5-116% with the relative standard deviation less than 9.2%. Such performance was attributed to recognition affinity, including the π-π affinity, hydrophobic effect, and hydrogen bond. These results demonstrated that TpPa-1 possessed great potential to be an excellent pretreatment medium for online separation and analysis of trace analytes in complex samples.

Surface-engineered sulfonation of ion-selective nanofiltration membrane with robust scaling resistance for seawater desalination

Inorganic fouling is one of the most critical issues in the seawater desalination process; it significantly deteriorates the desalination performance of the current seawater reverse osmosis (SWRO) membranes. Conventional nanofiltration (NF) membranes, which act as the pretreatment medium, are unable to effectively fractionate the scaling ions, Ca 2+ and SO 4 2− , resulting in fouling transfer from SWRO to the NF membranes. To address this issue, a new class of nanofiltration membranes was proposed and designed by surface engineering a custom-made sulfonated polyamide thin-film composite. Specifically, a new functional monomer, 4-aminobenzenesulfonic acid (ABSA), was chemically grafted onto a membrane surface via carbodiimide crosslinking chemistry. Due to the intentional optimization of mean pore sizes and surface charges, the as-prepared NF membranes (named BM-ABSA) exhibited extremely low Ca 2+ rejections (6.1 ± 0.4%) and moderate SO 4 2− rejections (57.5 ± 0.1%), corresponding to a higher ion selectivity (9.5) toward seawater compared to that of the benchmark commercial NF270 membrane (1.5). More importantly, the replacement of carboxylate groups in the substrate membrane matrix with the sulfonate groups considerably lowered the probability of the Ca–COOH chelation effect, which, in turn, facilitated steady NF-pretreatment processes without significant fouling. The subsequent SWRO process, using the BM-ABSA membrane-pretreated permeate as the feed solution, also proceeded well over a short-term operation with limited gypsum fouling. Overall, this study highlighted the effective inhibition of scaling by sulfonated NF membranes in the pretreatment process, validating their potential application for robust and efficient seawater desalination. • ABSA was chemically grafted onto the surface of NF membrane through EDC/NHS coupling reaction. • BM-ABSA-5 membrane showed a high ion-ion selectivity toward Ca 2+ and SO 4 2− . • The anti-scaling mechanism of –SO 3 H groups was investigated by molecular dynamics simulation. • Gypsum scaling on NF membrane and RO membrane was both inhibited in the hybrid NF-RO process for seawater desalination.

Application of imine covalent organic frameworks in sample pretreatment

亚胺类共价有机骨架(I-COFs)是有机单体根据席夫碱(Schiff-base)反应原理缩合形成的一类新型多孔晶体有机材料。I-COFs具有骨架密度低、比表面积大、孔隙率高、单体种类丰富、孔径尺寸可控、结构可功能化、合成方法多样和物化稳定性好等优点。近年来,I-COFs已成为材料科学领域的研究前沿,并广泛用于气体吸附、存储、催化、传感、光电材料等方面。I-COFs材料优异的物理化学性能使其非常适于用作复杂样品中痕量目标物的分离富集介质,其高比表面积、高孔隙率性能赋予了它极高的吸附负载量,这些性能使得目标分析物可被高效富集;通过控制有机单体的链段长度、几何结构、掺杂元素、取代基团等方面精确调控I-COFs的孔洞结构和功能化基团,从而实现目标痕量物质的选择性富集。目前,I-COFs材料在样品前处理领域作为新型萃取介质已引起了极大关注。该文综述了近年来I-COFs材料的主要类型、合成方法及其在固相萃取、磁性固相萃取、分散固相萃取和固相微萃取方面的研究进展,同时展望了I-COFs在样品前处理领域的发展前景。

Embryo Rescue via Artificial Seed Technique and Long-Term Preservation of &amp;lt;i&amp;gt;Zephyranthes&amp;lt;/i&amp;gt;

Zephyranthes is valued as a native ornamental landscaping plant and a traditional medicinal herb. Due to the low seed viability, this study was carried out to evaluate the potential of seed embryo rescue using the artificial seed technique and long-preservation in Z. atamasca and Z. grandiflora. Seed embryos were selected for encapsulation with different concentration of sodium alginate (3%, 4%, and 5%) and calcium chloride (either 25, 50, 75, and 100 mM) followed by no encapsulated embryos as a control. The greatest viability of encapsulated embryos was 95% in Z. grandiflora and 85% in Z. atamasca with the combination of 4% sodium alginate and 100 mM calcium chloride after two weeks at 5°C. The highest viability with A490nm0.12 and A490nm0.16 were achieved when embryos were cultured in pretreatment medium with 30 g/L sucrose in Z. grandiflora and Z. atamasca, respectively. The highest viability by TTC assay after cryopreservation was observed with 54% viability for Z. grandiflora and 48% viability with Z. atamasca, after 2 h of dehydration. Rain lilies embryos were successfully preserved functioned as artificial seed and cryopreservation using encapsulation-dehydration method has been established for both species that can be used for other flower species with some modifications.

Effects of pretreatment and leaching medium on the extraction efficiency of Au and Ag from a chalcopyrite leaching by-product

Precious metals such as gold (Au) and silver (Ag) are essential to our modern society due to their unique properties, such as high conductivity and physical and chemical resistance. They are teofn concentrated in by-products during the extraction of base metals. In the present work, a chalcopyrite leaching residue, constituted mainly of elemental sulfur and jarosites, was subjected to different pretreatments and leached with different leaching media to recover Au and Ag. The solid residue was pretreated by desulfurization,peroxidation,desulfurization+peroxidation and leached with cyanide, cyanide+glycine, and glycine. For comparison, samples without pretreatment were also leached using the same leaching media. Changes in the mineralogical species were followed to explain the effects of pretreatment and leaching medium on the dissolution of Au and Ag. Results indicate that the highest extraction of gold and silver (Au:99.50%, Ag:46.71%) is achieved by using a combined desulfurization+peroxidation pretreatment and cyanide as leaching medium.

Cellulosic glycols: an integrated process concept for lignocellulose pretreatment and hydrogenolysis

AbstractLignocellulose is the most abundant source of saccharides and it is therefore a promising feedstock for glycols, such as ethylene‐glycol, via catalytic hydrogenolysis of the polysaccharides that it contains. However, this catalytic hydrogenolysis step is hampered by the presence of lignin and other biomass contaminants, such as ash, which need to be removed in a pretreatment step. We propose an organosolv‐like pre‐treatment that can delignify and de‐ash lignocellulose to a level that allows it to be upgraded to glycol with comparable yields to pure cellulose under demanding hydrogenolysis conditions. This work identifies the main design constraints of the integrated process and provides an initial experimental validation of it. Pretreatment of biomass in water/ethanol/acetic acid solutions at 180–200 °C can reduce the lignin content of the solid residue to ≤6 wt%. The addition of an organic acid, such as acetic acid, appears important to improve the removal of the recalcitrant Ca2+, which is a known inhibitor of the tungstate catalyst typically used in this process. The pretreatment medium is designed to use the by‐product(s) of the process as organic solvent, to reduce the need for fresh solvent input. However, the process still needs a high solvent recovery (between 93.5 and 99.9 wt%). This can be achieved by selecting volatile component as organic solvent, as it allows recovery by evaporation from the dissolved lignin and ashes. © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley &amp; Sons Ltd.

Hepcidin Inhibits Ferroportin Activity Via a Rapid, Low‐Affinity, and Calcium‐Dependent Mechanism in Xenopus O ocytes Independent of Endocytosis

The cellular iron-exporter ferroportin (Fpn), under the control of the hormone hepcidin, serves as the key control point in iron homeostasis. The canonical mechanism by which hepcidin suppresses Fpn activity comprises hepcidin binding by Fpn and the subsequent internalization and degradation of the transporter. Here we explored hepcidin inhibition of 55Fe efflux from RNA-injected Xenopus oocytes expressing human Fpn. Hepcidin pretreatment rapidly (t½ = 10 ± [SEM] 0.3 min; r2 = 0.99, P < 0.001) inhibited Fpn-mediated 55Fe efflux at low affinity (EC50 = 0.5 ± 0.06 µM; r2 = 0.91, P < 0.001). In contrast, hepcidin-induced Fpn internalization in mammalian cells exhibits EC50 in the low nanomolar range. Hepcidin did not induce Fpn internalization, a conclusion based on the following observations: (i) Hepcidin action was only modestly temperature-dependent (temperature quotient, Q10 = 3.14 ± 0.25 over the range 16–26°C) whereas endocytosis is expected to be strongly temperature-dependent, i.e. Q10 in the order of 5–17 [Weigel PH and Oka JA (1981) J Biol Chem 256, 2615–17] (ii) Inhibition of Fpn by hepcidin proceeded even in the presence of blockers of clathrin-mediated (chlorpromazine) and clathrin-independent (filipin, genistein) endocytosis, and (iii) Hepcidin treatment produced no meaningful change in either the abundance of protein at the plasma membrane or membrane surface area (as determined by capacitance) in oocytes expressing Fpn, despite reducing Fpn-mediated iron transport by 65%. Hepcidin had no effect on Fpn activity when we removed calcium from the pretreatment medium (0 Ca2+, 1 mM EGTA). Our data reveal that hepcidin can directly block Fpn activity via a rapid, low-affinity, Ca2+-dependent mechanism that does not involve endocytosis. We speculate that the Xenopus oocyte lacks the specific signal by which hepcidin triggers Fpn internalization. The Xenopus oocyte is therefore an ideal model system in which to study the mechanism by which hepcidin directly blocks Fpn activity.

Thermochemical pretreatments of maize stem for sugar recovery: Comparative evaluation of microwave and conventional heating

Microwave (MW) heating is attracting great attention in biorefinery processes, because of its special dipole rotation heating mechanism. In the current study, MW and conventional heating methods were employed to assist the thermochemical pretreatments (H2O, H2SO4 or NaOH) of maize stem biomass. Their influences on sugar release and biomass compositions during pretreatments were comparably evaluated. Compared to conventional heating pretreatment, MW thermochemical pretreatments are highly efficient in sugar recovery, contributing to 4.3 times higher amount of sugar release (1.25 vs 0.30 μmol/mg biomass) with reaction time 8 times shorter (5 vs 40 min) and selectively producing glucose as the major constituent (0.75 μmol/mg biomass) using 0.2 M H2SO4 as pretreatment media. MW thermochemical pretreatment also effectively removed lignin (up to 91.6 %) within 5 min, which was significantly higher than conventional heating pretreatment (51.2 %). Conventional heating pretreatment successfully removed hemicellulose and converted the crystalline cellulose into amorphous cellulose, which is probably due to its longer heating time. Rapid MW thermochemical pretreatments efficiently fractionated hemicellulose and removed lignin content while keeping the crystalline cellulose structure. MW and conventional heating pretreatments led to similar digestibility of biomass solid residues. Overall, MW thermochemical pretreatment represents an energy efficient alternative strategy, as it consumed 25–34 folds less energy than conventional heating pretreatment for effective biomass fractionation and value-added chemical production.

Induction of Microspore Embryogenesis of Eggplant (&lt;i&gt;Solanum melongena&lt;/i&gt; L.) ‘Gelatik’

The haploid or double haploid plant of eggplants could be produced from microspore culture (embryogenesis of microspores). In the breeding programs, microspore can be developed into an embryo directly after exposure to stress treatment during cultured. Stress (temperature and starvation medium) is an important factor in the induction of embryogenesis microspore. This study aims to induced embryogenic microspores from eggplant CV. Gelatik. The stage late-uninucleate microspore (Vacuolate Microspore/VM) and early binucleate (Young Bicellular Pollen/YBP) are the suitable stages to induce multinucleate structure. There are 3 methods used in this research; 1) Determination of the stage development of microspore based on flower buds length and anther length. 2) Induction of embryogenic microspore on the pre-treatment and starvation medium. 3) After giving pre-treatment for 4 days, micropores were transferred to culture medium A2 at 28oC in dark conditions to induce the multicellular structures. This study reported that 50-68.51% of the VM+YBP stage obtained in the range of flower bud lengths of 10-17 mm, and 5.0-6.9 mm, the range of anther length containing VM+YBP of 50-77.48%. The pre-treatment heat shock at 33oC in the medium B for 2 days, produced embryogenic microspores with a high percentage, that is about 50.19%, while microspores at 25oC and 4oC respectively 46.17% and 49.28%. Pre-treatment for 4 days at 4 oC, 25 oC, and 33oC with the percentage of embryogenic microspores apiece 32.87%, 27.45%, and 37.34%. The multicellular (starlike) structure begins forming on the fifth day of incubation in culture medium (A2) after pre-treatment in B medium at 33oC.

Enhancement of the nanofibrillation of birch cellulose pretreated with natural deep eutectic solvent

In this study, we demonstrate a new bio-derived and non-toxic deep eutectic solvent composed of betaine hydrochloride (Bh) and glycerol (Gl) as a pretreatment medium for birch cellulose (Betula pendula) to prepare cellulose nanofibers (CNFs) using microfluidization. The co-solvent could readily penetrate into cellulose to swell the fibrillar structure and weaken the interaction within the hydrogen bond network. Moreover, the cationization of glycerol and cellulose by betaine hydrochloride further enhances the swelling process. All of these effects promote the nanofibrillation of cellulose and reduce the energy demand in CNF production. A high CNF mass yield of up to 72.5 % was obtained through co-solvent pretreatment using a Bh-to-Gl mole ratio of 1:2 at 150 °C for 1 h. The mole amount of betaine hydrochloride was noted to affect the nanofibrillation process and stability of the CNF suspension. The obtained CNFs possessed a cationic charge of 0.05–0.06 mmol/g, a diameter of 17–20 nm, and a degree of crystallinity of 67.7–74.4 %. The CNFs displayed good thermal stability comparable to that of the pristine cellulose. Thus, this study provides a green and efficient swelling strategy for producing CNFs with a low cationic charge density.

Enhancing packaging board properties using micro- and nanofibers prepared from recycled board

In this study, cellulose microfibers and cellulose nanofibers (CNF) prepared from recycled boxboard pulp using a mechanical fine friction grinder were used as reinforcements in a board sheet. Micro- and nanofibers manufactured by mechanical grinding have typically broad particle size distribution, and they can contain both micro- and nano-sized fibrils. Deep eutectic solvent of choline chloride and urea was used as a non-hydrolytic pretreatment medium for the CNF, and reference CNF were used without any chemical pretreatment. The CNF were ground using three grinding levels (grinding time) and their dosage in the board varied from 2 to 6 wt%. The results indicate that the board properties could be tailored to obtain a balance between the processability and quality of the products by adjusting the amount of CNF that was added (2–6 wt%). A preliminary cost assessment indicated that the most economical way to enhance the board strength properties was to add around 4% of CNF with a moderate grinding level (i.e., grinding energy of 3–4 kWh/kg). Overall, the strength properties of the manufactured board sheets improved by several dozen percentages when CNF was used as the reinforcement.

Hepcidin inhibits ferroportin in the Xenopus oocyte expression system via a calcium‐dependent mechanism that does not involve endocytosis

The cellular iron‐exporter ferroportin (Fpn), under the control of the hormone hepcidin, serves as a key control point in iron homeostasis. The canonical mechanism by which hepcidin suppresses Fpn activity comprises hepcidin binding by Fpn and the subsequent internalization and ubiquitin‐dependent degradation of the transporter. Here we explored hepcidin inhibition of 55Fe efflux from RNA‐injected Xenopus oocytes expressing human Fpn. Hepcidin pretreatment induced a rapid inhibition (t½ = 8.2 ± [SEM] 0.5 min; r2 &gt; 0.99, P &lt; 0.001) of Fpn‐mediated 55Fe efflux. Hepcidin had no effect on Fpn activity when we removed calcium from the pretreatment medium (0 Ca2+, 0.1 mM EGTA). The action of hepcidin was not dependent on endocytosis, a conclusion based on the following observations: (i) Inhibition of Fpn by hepcidin was only modestly temperature‐dependent (Q10= 2.5 ± SEM 1.4 over the range 17–27 °C) whereas endocytosis is expected to be strongly temperature‐dependent, Q10 in the order of 5–17 [Weigel PH and Oka JA (1981) J Biol Chem256, 2615–17]. (ii) Inhibition of Fpn by hepcidin proceeded even in the presence of blockers of clathrin‐mediated (chlorpromazine, Dynasore) and clathrin‐independent (filipin, genistein) endocytosis. (iii) Hepcidin treatment inhibited 55Fe efflux in oocytes expressing the (K→R)8‐Fpn mutant, in which 8 Lys residues required for ubiquitination and endocytosis of Fpn were mutated to Arg, as much as in wildtype Fpn. (iv) Confocal LSM imaging of wildtype Fpn‐GFP and (K→R)8‐Fpn‐GFP expression in oocytes revealed no detectable endocytosis of either protein after treatment with hepcidin. (v) Hepcidin treatment produced no meaningful change in membrane surface area (as determined by capacitance) of oocytes expressing Fpn, despite reducing Fpn‐mediated iron transport by 65%. Our data reveal that hepcidin can directly block Fpn activity via a Ca2+‐dependent mechanism that does not involve endocytosis. We speculate that the Xenopus oocyte lacks the specific signal by which hepcidin triggers Fpn internalization. The Xenopus oocyte is therefore an ideal model system in which to study the mechanism by which hepcidin directly blocks Fpn activity.Support or Funding InformationNIH grants R01 DK107309, P30 DK078392, and R25 HL115473, and the American Physiological Society