Green tea as inhibitor of the intestinal absorption of lipids: potential mechanism for its lipid-lowering effect

Animal and epidemiological studies suggest that green tea catechins may reduce the risk of cardiovascular diseases [e.g., coronary heart disease (CHD)]. The health benefit of green tea has been attributed to its antioxidant and anti-inflammatory properties; however, considerable evidence suggests that green tea and its catechins may reduce the risk of CHD by lowering the plasma levels of cholesterol and triglyceride. Although the mechanism underlying such effect of green tea is yet to be determined, it is evident from in vitro and in vivo studies that green tea or catechins inhibit the intestinal absorption of dietary lipids. Studies in vitro indicate that green tea catechins, particularly (-)-epigallocatechin gallate, interfere with the emulsification, digestion, and micellar solubilization of lipids, critical steps involved in the intestinal absorption of dietary fat, cholesterol, and other lipids. Based on the observations, it is likely that green tea or its catechins lower the absorption and tissue accumulation of other lipophilic organic compounds. The available information strongly suggests that green tea or its catechins may be used as safe and effective lipid-lowering therapeutic agents.     

Responses of plant and bird communities to prescribed burning in tallgrass prairies

Historic losses and fragmentation of tallgrass prairie habitat to agriculture and urban development have led to declines in diversity and abundance of plants and birds associated with such habitat. Prescribed burning is a management strategy that has potential for restoring and rejuvenating prairies in fragmented landscapes, and through such restoration, might create habitat for birds dependent upon prairies. To provide improved data for management decision-making regarding the use of prescribed fire in tallgrass prairies, we compared responses of plant and bird communities on five burned and five unburned tallgrass prairie fragments at the DeSoto National Wildlife Refuge, Iowa, USA, from 1995 to 1997. Overall species richness and diversity were unaffected by burning, but individual species of plants and birds were affected by year-treatment interactions, including northern bobwhite (Colinus virginianus) and ring-necked pheasant (Phasianus colchicus), which showed time-delayed increases in density on burned sites. Analyses of species/area relationships indicated that, collectively, many small sites did make significant contributions to plant biodiversity at landscape levels, supporting the overall conservation value of prairie fragments. In contrast, most birds species were present on larger sites. Thus, higher biodiversity in bird communities which contain area-sensitive species might require larger sites able to support larger, more stable populations, greater habitat heterogeneity, and greater opportunity for niche separation.     

Modification of cap group in delta-lactam-based histone deacetylase (HDAC) inhibitors

Novel delta-lactam-based HDAC inhibitors which have various substituted benzyl, bi-aromatic cap groups were prepared using ring closure metathesis reaction, and evaluated their HDAC inhibitory activities and anti-proliferative effects. Among prepared analogues, 11m and 11o have very strong HDAC enzymatic inhibition and showed the most potent growth inhibitory activity to five human tumor cell lines including PC-3, ACHN, NUGC-3, HCT-15, and MBA-MB-231 tumor cell lines. Compounds 11m and 11o also showed good tumor growth inhibition of MDA-MB-231 cells in in vivo xenograft model. Structure-activity relationship study using docking model explained the significance of hydrophobic aromatic cap groups for their in vitro activities.     

Analysis of ALS5 and ALS6 allelic variability in a geographically diverse collection of Candida albicans isolates

The Candida albicans ALS (agglutinin-like sequence) gene family encodes eight cell-surface glycoproteins, some of which function in adhesion to host surfaces. ALS genes have a central tandem repeat-encoding domain comprised entirely of head-to-tail copies of a conserved 108-bp sequence. The number of copies of the tandemly repeated sequence varies between C. albicans strains and often between alleles within the same strain. Because ALS alleles can encode different-sized proteins that may have different functional characteristics, defining the range of allelic variability is important. Genomic DNA from C. albicans strains representing the major genetic clades was PCR amplified to determine the number of tandemly repeated sequence copies within the ALS5 and ALS6 central domain. ALS5 alleles had 2-10 tandem repeat sequence copies (mean=4.82 copies) while ALS6 alleles had 2-8 copies (mean=4.00 copies). Despite this variability, tandem repeat copy number was stable in C. albicans strains passaged for 3000 generations. Prevalent alleles and allelic distributions varied among the clades for ALS5 and ALS6. Overall, ALS6 exhibited less variability than ALS5. ALS5 deletions can occur naturally in C. albicans via direct repeats flanking the ALS5 locus. Deletion of both ALS5 alleles was associated particularly with clades III and SA. ALS5 exhibited allelic polymorphisms in the coding region 5' of the tandem repeats; some alleles resembled ALS1, suggesting recombination between these contiguous loci. Natural deletion of ALS5 and the sequence variation within its coding region suggest relaxed selective pressure on this locus, and that Als5p function may be dispensable in C. albicans or redundant within the Als family.     

Ethanol extract of fermented soybean, Chungkookjang, inhibits the apoptosis of mouse spleen, and thymus cells

Apoptosis is a step of the cell cycle which is important in the regulation of immune cell populations. Chungkookjang is a Korean traditional fermented soybean containing microorganisms, enzymes, and bioactive compounds which was used in the treatment of mouse spleen as well as thymus cells (CH1-fermented soybean containing barley, wormwood, and sea tangle; CH2-fermented soybean) and was found to exhibit substantially reduced small DNA fragmentation. An MTT assay showed that the treatment of CH1 and CH2 into the mouse splenocytes and thymocytes sharply increased their survival. Moreover, a FACS analysis also showed that CH1 and CH2 are effective at suppressing the apoptosis of splenocytes and thymocytes. The fermented soybean isoflavone concentrations, which are implicated in lowering breast and prostate cancers, lowering the risk of cardiovascular diseases, and improving bone health, were determined using Capillary Electrophoresis-Electrochemical Detection (CE-ED). The amount of Daidzein in fermented soybean significantly increased by 44-fold dramatically, compared with those in unfermented soybean. In this study, we demonstrated that ethanol extracts of Chungkookjang promote the survival of the mouse spleen and thymus cells in culture by suppressing their apoptotic death. Future studies should investigate which genes are related to apoptosis of the immune cells.     

Factors indicating culture status during cultivation of Spirulina (Arthrospira) platensis

Factors indicating culture status of two Spirulina platensis strains were monitored in a batch mode cultivation for 36 days. Changing mode in all factors showed a common turning point, indicating shift of cell or culture status. Mean biomass productivity was highly sustained until day 22, chlorophyll a concentration peaked on day 22, pH value was >12 on day 22, coil number was abruptly shortened on day 22, and floating activity was sustained at greater than 79% after day 22, indicating that day 22 is a criterion reflecting phase-transfer in cell physiology in a batch culture system. Many of these changes may have been caused by increased pH, suggesting that pH control is essential for mass production of S. platensis. Fluctuations in floating activity were likely induced by the number of cellular gas vacuoles. Consequently, coil number per trichome and floating activity of S. platensis could readily act as simple indicators for determination of culture status or harvesting time of cells.     

Characterization of an extracellular lipase in Burkholderia sp. HY-10 isolated from a longicorn beetle

Burkholderia sp. HY-10 isolated from the digestive tracts of the longicorn beetle, Prionus insularis, produced an extracellular lipase with a molecular weight of 33.5 kDa estimated by SDS-PAGE. The lipase was purified from the culture supernatant to near electrophoretic homogenity by a one-step adsorption-desorption procedure using a polypropylene matrix followed by a concentration step. The purified lipase exhibited highest activities at pH 8.5 and 60 degrees . A broad range of lipase substrates, from C4 to C18 rho-nitrophenyl esters, were hydrolyzed efficiently by the lipase. The most efficient substrate was rho-nitrophenyl caproate (C6). A 2485 bp DNA fragment was isolated by PCR amplification and chromosomal walking which encoded two polypeptides of 364 and 346 amino acids, identified as a lipase and a lipase foldase, respectively. The N-terminal amino acid sequence of the purified lipase and nucleotide sequence analysis predicted that the precursor lipase was proteolytically modified through the secretion step and produced a catalytically active 33.5 kDa protein. The deduced amino acid sequence for the lipase shared extensive similarity with those of the lipase family I.2 of lipases from other bacteria. The deduced amino acid sequence contained two Cystein residues forming a disulfide bond in the molecule and three, well-conserved amino acid residues, Ser131, His330, and Asp308, which composed the catalytic triad of the enzyme.     

Identification and characterization of small RNAs from vernalized<Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are two major classes of small non-coding RNAs with important roles in the regulation of gene expression, such as mRNA degradation and translational repression, heterochromatin formation, genome defense against transposons and viruses in eukaryotes. MiRNA- and siRNA-directed processes have emerged as a regulatory mechanism for growth and development in both animals and plants. To identify small RNAs that might be involved in vernalization, a process accelerating flowering brought on by a long period of cold, we generated a library of small RNAs from Arabidopsis that had been subject to vernalization. From the analysis of the library, 277 small RNAs were identified. They were distributed throughout all the five chromosomes. While the vast majority of small RNA genes locate on intergenic regions, others locate on repeat-rich regions, centromeric regions, transposon-related genes, and protein-coding genes. Five of them were mapped to convergent overlapping gene pairs. Two-hundred and forty of them were novel endogenous small RNAs that have not been cloned yet from plants grown under normal conditions and other environmental stresses. Seven putative miRNAs were up- or down-regulated by vernalization. In conclusion, many small RNAs were identified from vernalized Arabidopsis and some of these identified small RNAs may play roles in plant responses to vernalization.