Carbon Molecular Sieve Membranes with Ultra-Thin Selective Skin Layer by Pyrolysis of Porous Hollow Fibers.

Translating carbon molecular sieve (CMS) membranes into highly scalable hollow fiber geometry with ultra-thin selective layer (<1 µm) for gas separation remains as great challenge. The porous support layer of precursor hollow fiber membranes is prone to collapse during pyrolysis, which induces thick skin layer (15-50 µm) of CMS hollow fiber membranes. Here, a novel strategy is present to obtain an ultra-thin selective skin layer by carbonization of hollow fiber membranes with porous skin. P84-based defect-free CMS hollow fiber membranes with ultra-thin selective skin layer (0.9 µm) for gas separation are prepared without any coating or complex chemical pretreatment. Compared with the carbon membranes derived from defect-free fibers, the H2 permeance (93.9 GPU) of CMS membranes derived from the porous fibers increases ≈1353% with comparable selectivity of H2/CH4 (143) and higher H2/N2 (120). Furthermore, the porous fibers are pre-aged near the Tg in N2 conditions before carbonization, and the H2 permeance of the derived CMS hollow fiber membranes reached 147 GPU (increased 2180%). It is a new facile way to prepare CMS hollow fiber membranes with ultra-thin selective layer by porous fibers, demonstrating its versatile potential in gas separation or organic liquids separation.

[Phylogenetic diversity of the culturable rare actinomycetes in marine sponge Hymeniacidon perlevis by improved isolation media].

OBJECTIVE: Based on the molecular diversity information, seven actinomycete-selective culture media and isolation conditions were modified to isolate and cultivate diverse rare actinomycetes from Hymeniacidon perlevis. METHODS: Modified, selective cultivation and enrichment media were used, with the addition of an elemental solution of simulating the elemental composition of marine sponge H. perlevis. Restriction Fragment Length Polymorphism (RFLP) analysis of 16S rDNA sequence was used to reveal the diversity of culturable rare actinomycetes. RESULTS: A total of 59 actinomycete strains were isolated from the marine sponge H. perlevis. A total of 27 representative actinomycetes were selected according to their morphological feature, color and pigments. They gave 15 different RFLP patterns after digesting their PCR products of 16s rDNA with Hha I. The results showed that these isolates belonged to 10 genera: Streptomyces, Nocardiopsis, Micromonospora, Cellulosimicrobium, Gordonia, Nocardia, Prauseria, Pseudonocardia , Saccharomonospora and Microbacterium. CONCLUSION: The modified isolation media and selective cultivation procedures are highly effective in the recovery of culturable actinomycetes from the marine sponge H. perlevis, resulting in the highest diversity of culturable rare actinomycetes from any sponges.

Culture-independent nested PCR method reveals high diversity of actinobacteria associated with the marine sponges Hymeniacidon perleve and Sponge sp.

A culture-independent nested polymerase chain reaction (PCR) technique was used to investigate the diversity of actinobacteria communities associated with the sponges Hymeniacidon perleve and Sponge sp. The phylogenetic affiliation of sponge-derived actinobacteria was then assessed by 16S rRNA sequencing of cloned DNA fragments. A total of 196 positive clones were screened by restriction fragment length polymorphism (RFLP) analysis; 48 unique operational taxonomic units (OTUs) were selected for sequencing. Rarefaction analysis indicated that the clone libraries represented 93% and 94% of the total estimated diversity for the two species, respectively. Phylogenetic analysis of sequence data revealed representatives of various phylogenetic divisions, which were related to the following ten actinobacterial genera: Acidimicrobium, Corynebacterium, Propionibacterium, Actinomyces, Micrococcus, Microbacterium, Streptomyces, Mycobacterium, Cellulosimicrobium, Sporichthya, and unidentified actinobacterial clones. A sponge-specific, previously uncultured actinobacteria community grouped within the subclass Acidimicrobidae was discovered from both H. perleve and Sponge sp. Sequences belonging to Acidimicrobium in the H. perleve and the Sponge sp. clone libraries represented 33% and 24% of the clones, respectively. In the Sponge sp. clone library Mycobacterium dominated, accounting for 70% of all clones. The presence of Acidimicrobium and mycobacteria within two sponges can lay the groundwork for attempts to culture these interesting bacteria for industrial applications.

Ginsenoside metabolites, rather than naturally occurring ginsenosides, lead to inhibition of human cytochrome P450 enzymes.

There is still an argument about ginseng-prescription drug interactions. To evaluate the influence on cytochrome P450 (P450) activities of ginseng in the present study, the influence on P450 activities of naturally occurring ginsenosides and their degradation products in human gut lumen was assayed by using human liver microsomes and cDNA-expressed CYP3A4. The results showed that the naturally occurring ginsenosides exhibited no inhibition or weak inhibition against human CYP3A4, CYP2D6, CYP2C9, CYP2A6, or CYP1A2 activities; however, their main intestinal metabolites demonstrated a wide range of inhibition of the P450-mediated metabolism. There was no mechanism-based inhibition found on these P450 isoforms. It is noteworthy that Compound K, protopanaxadiol (Ppd), and protopanaxatriol (Ppt) all exhibited moderate inhibition against CYP2C9 activity, and Ppd and Ppt also exhibited potent competitive inhibition against CYP3A4 activity. We suggest that after oral administration, naturally occurring ginsenosides might influence hepatic P450 activity in vivo via their intestinal metabolites.

Influence of ginsenoside Rh1 and F1 on human cytochrome p450 enzymes.

For an oral herbal medicine, the components that can enter the systemic circulation may be the really effective components. In the present study, the effects on the human cytochrome P450 activities of ginsenoside Rb (1) and two hydrolysis products of 20( S)-protopanaxatriol ginsenosides in humans, namely ginsenoside Rh (1) and F (1), which may reach the systemic circulation after oral administration of ginseng extract, were evaluated. Our results showed that Rb (1) exhibited no marked effects on the activities of human cytochrome P450, whereas Rh (1) and F (1) exhibited competitive inhibition of the activity of CYP3A4 with K(i) values of 57.7 +/- 9.6 microM and 67.8 +/- 16.2 microM, respectively. F (1) also exhibited a weaker inhibition of the activity of CYP2D6. Rh (1) exhibited a weak stimulation rather than an inhibition of the activity of CYP2E1. The degradation of ginsenosides in the gastrointestinal tract may play an important role in the ginseng-associated drug-drug interactions, but the effects might be not due to Rh (1) and F (1).

Formulation of a basal medium for primary cell culture of the marine sponge Hymeniacidon perleve.

Marine sponge cell culture is a potential route for the sustainable production of sponge-derived bioproducts. Development of a basal culture medium is a prerequisite for the attachment, spreading, and growth of sponge cells in vitro. With the limited knowledge available on nutrient requirements for sponge cells, a series of statistical experimental designs has been employed to screen and optimize the critical nutrient components including inorganic salts (ferric ion, zinc ion, silicate, and NaCl), amino acids (glycine, glutamine, and aspartic acid), sugars (glucose, sorbitol, and sodium pyruvate), vitamin C, and mammalian cell medium (DMEM and RPMI 1640) using MTT assay in 96-well plates. The marine sponge Hymeniacidon perleve was used as a model system. Plackett-Burman design was used for the initial screening, which identified the significant factors of ferric ion, NaCl, and vitamin C. These three factors were selected for further optimization by Uniform Design and Response Surface Methodology (RSM), respectively. A basal medium was finally established, which supported an over 100% increase in viability of sponge cells.

The inhibitory effect of intestinal bacterial metabolite of ginsenosides on CYP3A activity.

The intestinal bacterial metabolites of ginsenosides are responsible for the main pharmacological activities of ginseng. The purpose of this study was to find whether these metabolites influence hepatic metabolic enzymes and to predict the potential for ginseng-prescription drug interactions. Utilizing the probe reaction of CYP3A activity, testosterone 6beta-hydroxylation, the effects of derivatives of 20(S)-protopanaxadiol and 20(S)-protopanaxatriol families on CYP3A activity in rat liver microsomes were assayed. Our results showed that ginsenosides from the 20(S)-protopanaxadiol and 20(S)-protopanaxatriol family including Rb1, Rb2, Rc, Compound-K, Re, and Rg1 had no inhibitory effect, whereas Rg2, 20(S)-panaxatriol and 20(S)-protopanaxatriol exhibited competitive inhibitory activity against CYP3A activity in these microsomes with the inhibition constants (Ki) of 86.4+/-0.8 microM, 1.7+/-0.1 microM, and 3.2+/-0.2 microM, respectively. This finding demonstrates that differences in their chemical structure might influence the effects of ginsenosides on CYP3A activity and that ginseng-derived products might have potential for significant ginseng-drug interactions.

Significant enhancement of photobiological H2 evolution by carbonylcyanide m-chlorophenylhydrazone in the marine green alga Platymonas subcordiformis.

A marine green microalga, Platymonas subcordiformis, photo-synthetically generates H(2) but only transiently at a negligible yield when exposed to light after a period of dark anaerobic incubation. A protonophore uncoupler, carbonyl cyanide m-chlorophenylhrazone (CCCP) significantly increased the yield of H(2) photo-production. CCCP optimally at 15 microM gave 4.9 ml H(2) after 8 h light irradiation in 1 l algal cell culture at 1.8 x 10(6) cells ml(-1). The H(2) yield at 15 microM CCCP was increased by 240-fold when compared to the control. This improvement may be by CCCP disrupting the proton motive force thus facilitating proton transfer across the thylakoidal membrane.

Attachment of marine sponge cells of Hymeniacidon perleve on microcarriers.

Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15-20% interface. The highest attachment ratio of 41% was obtained for the cell fraction at Ficoll 15-20% interface on glass beads, which was significantly higher than that of a mixed cell population (18%). The attachment kinetics on glass beads indicated that the attachment was completed within 1 h. Cell attachment ratio decreases with increase in cell-to-microcarrier ratio (3-30 cells/bead) and pH (7.6-9.0). The addition of serum and BSA (bovine serum albumin) reduced the cell attachment on glass beads.

Optimizing the formation of in vitro sponge primmorphs from the Chinese sponge Stylotella agminata (Ridley).

The establishment and optimization of in vitro primmorph formation from a Chinese sponge, Stylotella agminata (Ridley), collected from the South China Sea, were investigated. Our aims were to identify the key factors affecting primmorph formation in this species and to optimize the technique for developing an in vitro primmorph culture system. The size of dissociated cells from S. agminata is relatively small, in the range between 5 and 10 microm. Round-shaped primmorphs of less than 100 microm were formed 3 days after transferring the dissociated cells into seawater containing Ca(2+) and Mg(2+). The effect of various cell dissociation conditions, inoculum cell density, concentration of antibiotics, pH, and temperature was further investigated upon the formation of primmorphs. The time required for primmorph formation, primmorph size distribution, and the proliferating capability were microscopically documented. Healthy sponge S. agminata, inoculum cell density and culture temperature play a critical role for the successful formation of primmorphs and that the microbial contamination will have to be controlled.