侧耳菌原生质体融合子的子实体发育及遗传重组

通过原生质体融合技术得到侧耳菌亲和与非亲和菌种的融合产物,亲和菌种间体细胞杂交得到异核体,而非亲和菌种杂交得到保留有双亲基因的结合体（核）。结合核子实体发育受光照、温度、营养及培养基的物理状态等因素影响。结合体不能形成初始融合菌落,但大多数成熟的子实体中存在锁状联合,与异核体相比,结合体具生长速率缓慢,有丝分裂阶段形成锁状联合及子实体发育不同步等特点。体细胞杂交后代可以分离到四种遗传型菌落：原养型、一种亲本营养缺陷型、另一亲本营养缺陷型及重组子营养缺陷型。一些结合体具备异常等位基因,说明在受体细胞染色体重排中有大片段随机整合位点。     

Stability of chitosan nanoparticles for L-ascorbic acid during heat treatment in aqueous solution

This study investigated the stability and characteristics of L-ascorbic acid (AA)-loaded chitosan (CS) nanoparticles during heat processing in aqueous solutions. AA-loaded CS nanoparticles were prepared by ionic gelation of CS with tripolyphosphate (TPP) anions. The smallest CS nanoparticles (170 nm) were obtained with a CS concentration of 1.5 mg/mL and a TPP concentration of 0.6 mg/mL. As the concentration of AA increased from 0.1 to 0.3 mg/mL, the particle size increased, while the zeta potential decreased, and the encapsulation efficiency of AA remained within a fixed range (10-12%). During heat processing at various temperatures, the size and zeta potential of the particles decreased rapidly in the first 5 min and then slowly fell to the regular range. At the beginning of the release profiles, the burst release-related stability of the surface increased with the temperature. Then, the release of the internal AA was constantly higher with a longer release time. Consequently, it was confirmed that the stability of AA-loaded CS nanoparticles was affected by temperature but that the internal stability was greater than the surface stability. These results demonstrate the stability of CS nanoparticles for AA during heat processing and suggest the possible use of AA-loaded CS nanoparticles to enhance antioxidant effects because of the continuous release of AA from CS nanoparticles in food processing.     

Structural and biological characterization of sulfated-derivatized oat beta-glucan

The structural, physicochemical, and biological properties of sulfated oat beta-glucan were characterized. The degree of substitution of the sulfated oat-beta glucan was obtained by elemental analysis, which was 0.68. Compared to native oat beta-glucan, the FT-IR spectra of the derivative showed two new absorption bands at 1250 and 810 cm(-)(1), which would be attributed to (S=O) and (C-O-S) groups, respectively. The molecular weight of the sulfated beta-glucan was determined to be 68 kDa and its viscosity decreased by almost 2 orders of magnitude while its solubility increased by more than 100% compared to that of the native beta-glucan. In addition, the sulfation caused the reduction of in vitro bile acid binding capacity of oat beta-glucan due to the new anionic character and decreased molecular weight. The sulfated derivative exhibited, however, anticoagulant activity which showed a concentration-dependent increase.     

Thermal Insulation Performance of Cotton and PET-based Hybrid Fabrics Impregnated with Silica Aerogel via a Facile Dip-dry Process

We report the morphological features and thermal insulation properties of a series of cotton- and PET-based hybrid fabrics impregnated with silica aerogel. For the purpose, commercially available cotton and PET knitted fabrics were dipped into aqueous dispersions including different silica aerogel contents, dried, and stacked to 1, 3, and 5 layers. The SEM images revealed that the silica aerogel particles were well incorporated into cotton or PET knitted fabrics. The thermal insulating performance of the hybrid fabrics as functions of the silica aerogel content and the number of layers of stacked fabrics were characterized by monitoring the surface temperatures of the fabrics on a plate with a wide temperature range of ~50-80 oC using an infrared camera. The higher thermal insulation performance was attained for both cotton- and PET-based hybrid fabrics with higher silica aerogel contents. In addition, 3-layered hybrid fabrics exhibited noticeably improved thermal insulation performance, compared to 1- or 5-layered fabrics. The thermal insulation property of the cotton-based hybrid fabrics was dominantly influenced by silica aerogel than that of PET-based hybrid fabrics. The overall results demonstrated that the cotton- and PET-based hybrid fabrics with silica aerogel manufactured by a facile dip-dry process could be utilized as protective garments, heat-sensitive devices, pipes, automotive, aircrafts, and buildings for thermal insulation applications.     

Taeanamides A and B,Nonribosomal Lipo-Decapeptides Isolated from an Intertidal-Mudflat-Derived Streptomyces sp.

Two new lipo-decapeptides, namely taeanamides A and B (1 and 2), were discovered from the Gram-positive bacterium Streptomyces sp. AMD43, which was isolated from a mudflat sample from Anmyeondo, Korea. The exact molecular masses of 1 and 2 were revealed by high-resolution mass spectrometry, and the planar structures of 1 and 2 were elucidated using NMR spectroscopy. The absolute configurations of 1 and 2 were determined using a combined analysis of ¹H-¹H coupling constants and ROESY correlations, the advanced Marfey’s method, and bioinformatics. The putative nonribosomal peptide synthetase pathway for the taeanamides was identified by analyzing the full genome sequence data of Streptomyces sp. AMD43. We also found that taeanamide A exhibited mild anti-tuberculosis bioactivity, whereas taeanamide B showed significant bioactivity against several cancer cell lines.     

Forest conversion adversely affects native Macrobrachium shrimp assemblages in tropical Malaysian streams

1. Commodity-driven forest conversion represents one of the most severe threats to freshwater biodiversity in Southeast Asia, notably causing population declines and the extinction of freshwater fish species.
2. Although a variety of freshwater taxa are likely to be adversely affected by forest conversion, little is known about the impact on ecologically and economically important invertebrates such as decapod crustaceans.
3. This study evaluated the impact of forest conversion and land-use change on freshwater Macrobrachium shrimp species, using species richness, abundance, and environmental data collected from 20 streams across southern Peninsular Malaysia. Streams were located in three types of landscape: forest; oil palm plantation; and mixed land use, comprising young secondary forest, small-scale plantations, patches of open and sparsely vegetated areas, and agricultural fields and clearings.
4. Generalized linear models showed that even incomplete change from forest habitats to mixed land use and oil palm plantation resulted in significantly lower Macrobrachium native species richness and higher non-native species abundance. Native species richness was positively correlated with canopy cover, leaf litter, substrate size, and dissolved oxygen, and was negatively correlated with water temperature and conductivity. Native species richness was also negatively correlated with non-native species abundance, with non-native species abundance increasing along the human disturbance gradient.
5. These results highlight the need for riparian habitat protection to conserve native Macrobrachium and limit the spread of non-native species. A management priority should be to maintain or restore optimum instream habitat conditions for shrimps, which would also benefit fish and other benthic macroinvertebrates. Suitable riparian management requires substantial support and funding from multiple stakeholders, but it can be aligned with other catchment-based strategies to optimize the use of limited resources available for freshwater biodiversity conservation.