Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO₂ (SC-CO₂) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO₂ method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO₂ (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO₂ oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO₂. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO₂ extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.     

Simple sequence repeat analysis of genetic diversity among Acetyl‐CoA carboxylase inhibitor‐resistant and ‐susceptible Echinochloa crus‐galli and E. oryzicola populations in Korea

Echinochloa species are amongst the most problematic weeds in rice fields of Korea. The steady reliance on the Acetyl‐CoA carboxylase (ACCase) and acetolactate synthase inhibiting herbicides for control of these weeds has led to resistance to these herbicides. The objective of this study was to assess the genetic diversity among populations of ACCase inhibitor‐resistant and ‐susceptible Echinochloa crus‐galli and E. oryzicola in Korea, to better understand their population structure and possible origins of resistance. Seven simple sequence repeat markers were applied to assess the genetic diversity between resistant and susceptible E. crus‐galli and E. oryzicola from 12 populations in Korea. Genetic diversity was slightly higher in the resistant group. The Unweighted Pair Group Method using Arithmetic algorithm (UPGMA) dendrogram generated two distinct clades. One clade consisted of Echinochloa spp. from three populations, i.e. Anmyeondo, Gimje 4 and Gongju, which are resistant and differentiated from the susceptible populations, and the other clade contained the rest of the populations. Structure modelling supported two clades of UPGMA clustering. Based on these data, we can infer that some resistant populations are greatly differentiated, whereas other resistant biotypes are still building up resistance in rice fields in Korea. Resistance traits will be fixed and continue to spread over time without proper control measures.     

The manufacture and Physical properties of Hanji Composite nonwovens utilizing the Hydroentanglement process

This study aims to develop the new Hanji paper composite nonwovens that positively affect the antimicrobial activity, deodorization, and comfort functionality of natural materials of cotton and rayon that have high consumer preference and to manufacture new sanitary goods and facial mask sheets utilizing the hydroentanglement process. The results of the study through the evaluation analysis of functionality and properties of the composite nonwovens developed in this study are as follows. The manufactured composite nonwovens have improved functionalities of absorption velocity, antimicrobial activity, and deodorization from the base materials of C45 (Cotton (45 g/m²)) and R53 (Rayon/PET (53 g/m²)). Also, physical properties such as tensile strength, breaking extension, and tearing strength have improved significantly. The texture of composite nonwovens of Mulberry 70 %/Pulp 30 %(15) of Hanji paper weight 15 g/m² with base material did not show a significant difference compared to the nonwovens of C45 and R53. However, the soft texture of composite nonwovens of Mulberry 70 %/Pulp 30 %(25) of Hanji paper weight 25 g/m² with base material showed somewhat of a decrease compared to the nonwovens of C45 and R53. When considering the marketability, the composite nonwovens of Mulberry 70 %/Pulp 30 %+C45 and Mulberry 70 %/Pulp 30 %+R53 were estimated to be a positive development for use in female sanitary products and facial mask sheet products. These newly developed Hanji composite nonwovens could contribute to the development of high value added products that would satisfy the consumers.     

Low-temperature pyrolysis on jute fibers as a thermochemical modification method

Low-temperature pyrolysis up to 200, 250, 300 °C was conducted in order to remove non-cellulosic compounds without damaging the structure of the cellulose in jute fibers. The chemical, morphological, and mechanical aspects of prepared low-temperature pyrolyzed jute fibers were investigated by Fourier transform infrared (FTIR) spectroscopy, the wettability test in water/dichloromethane system, moisture content measurement, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and tensile test using universal testing machine (UTM). It was confirmed that hydrophilic compounds including absorbed water, low molecular weight compounds such as waxes, hemicellulose, and lignin were largely removed from the fibers. Increasing amounts of non-cellulosic compounds were removed as the maximum pyrolysis temperature was increased. The degree of hydrophilic nature of jute fibers were reduced by low-temperature pyrolysis and thus water absorptivity of pyrolyzed jute fibers was reduced as maximum pyrolysis temperature increased. Furthermore, XRD analysis and morphological studies by SEM indicated that the crystalline structure of native cellulose was rarely damaged after pyrolysis up to 300 °C. In case of mechanical properties, breaking tenacity and breaking strain of the fibers decreased with increasing maximum pyrolysis temperatures because flaws formed on the surface of pyrolyzed jute fibers acted as weak-links. In agreement with predictions made according to Weibull’s weakest-link theory, it was found that shortened pyrolyzed jute fibers could have higher breaking tenacities compared with raw jute fibers of the same length. In addition, the compatibility with hydrophobic matrix was investigated by the mechanical properties of polypropylene (PP) reinforced with jute fibers. Consequently, it was hypothesized that low-temperature pyrolysis could be used to process raw jute fibers for use as short fiber reinforcements in fiber-polymer systems or be a simple and effective pretreatment method for a wide range of further chemical treatments.     

Epidemiological cut-off values for disc diffusion data generated by standard test protocols from <Emphasis Type="Italic">Edwardsiella tarda</Emphasis> and <Emphasis Type="Italic">Vibrio harveyi</Emphasis>

The susceptibility of 52 isolates of Edwardsiella tarda and 54 isolates of Vibrio harveyi to 12 antibiotics was established using internationally standardised disc diffusion protocols. Normalised resistance interpretation was employed to generate statistically valid epidemiological cut-off values for these susceptibility data. For three of these 24 species/antibiotic data sets, there were insufficient fully sensitive strains to allow analysis and for an additional two there were sufficient fully susceptible isolates to allow only a provisional estimate to be made. The data sets for a further two species/antibiotic combinations were considered too diverse to allow the calculation of a valid cut-off value. Valid epidemiological cut-off values were, therefore, calculated for 17 species/antibiotic combinations. It is argued that these cut-off values will greatly facilitate the performance of studies designed to monitor the consequence of antibiotic use in aquaculture. They will also facilitate the prudent and rational choice of antibiotics to be applied therapeutically in commercial farming of aquatic animals.     

Development of superhydrophobic polyester fabrics using alkaline hydrolysis and coating with fluorinated polymers

Alkaline hydrolysis is one of the most classic fiber finishing methods, however, its potential as tuning surface superhydrophobicity in mass scale has not been studied much. In this research, fine roughness was formed on the polyester fiber surfaces by alkaline hydrolysis at room temperature and fluorinated polymer mixtures were further coated. The developed superhydrophobic fabrics were evaluated in terms of structural changes, mechanical properties, surface hydrophobicity, and permeability for practical applications. As alkaline hydrolysis treatment time increased, surface roughness was increased as a lot of nano-craters were generated with the decrease of fabrics weight and tensile strength as well. As air pockets formed through nano-craters on the fiber surfaces, static contact angle increased, and shedding angle tended to decrease. In this study, the sample treated with alkaline hydrolysis for 20 minutes showed the highest static contact angle of 167.8±1.3° and lowest shedding angle of 4.4±2.3°. Considering tensile strength loss, however, the 15-minute alkaline hydrolyzed fabrics which showed static contact angle of 162.2±2.7° and shedding angle of 8.8±0.2° was selected as the optimal condition for practical application. The newly developed superhydrophobic fabrics were found to have higher water vapor and air permeability than those of untreated samples. At the same time, fluoropolymer coating played a certain role for tensile strength and water vapor permeability demonstrating the importance of understanding and designing proper fluorinated-compound treatment processes.     

<Emphasis Type="Italic">Pseudomonas</Emphasis> sp. LSW25R,antagonistic to plant pathogens,promoted plant growth,and reduced blossom-end rot of tomato fruits in a hydroponic system

A Gram-negative rhizobacterial isolate (LSW25) antagonistic to Pseudomonas corrugata, a vein necrosis pathogen of tomato, and promotes the growth of tomato seedlings was isolated from surface-sterilised tomato roots. A spontaneous rifampicin-resistant mutant (LSW25R) was selected to facilitate its tracking, and identified as Pseudomonas sp. and named as Pseudomonas sp. LSW25R (LSW25R), based on its sequences of the internal transcribed spacer (ITS) region and 16 S rRNA gene. LSW25R inhibited mycelial growth of 12 other plant fungal pathogens such as Botrytis cinerea on V8 agar plates. By using a scanning electron microscope, LSW25R colonised not only the root surface around the natural aperture of tomato radicles but also under epidermal cells like endophytic bacteria. LSW25R successfully colonised the roots of tomato, eggplant and pepper seedlings, significantly promoted the fresh weight, height and dry matter of tomato plants at 10⁸ cfu·ml⁻¹, and increased the plant growth of eggplants and peppers at 10⁴ cfu·ml⁻¹, suggesting that the optimal population density of LSW25R for growth promotion varies from species to species. Moreover, densities of LSW25R inside roots and the lowest leaf of tomato plants were > 9.3 × 10³ cfu·g⁻¹. Although the growth promotion of tomato by LSW25R was observed under N- or Ca-deficient conditions as well as a standard nutrient condition, the uptake of calcium was increased only under the standard nutrient condition. In a hydroponic system, LSW25R not only successfully colonised the rhizosphere during cultivation due to its broad spectrum of antifungal activity and endophytic colonisation, but also reduced blossom-end rot of tomato fruits presumably through increasing calcium uptake.