A convenient method for saponin isolation in tumour therapy

Saponinum album (Merck), which is a crude mixture of saponins from Gypsophila paniculata L., was shown to improve the anti cancer therapy when used in vivo in combination with saporin-based targeted toxins. Unfortunately saponinum album cannot be used for further development since Merck has ceased its production in the 1990s. As pure saponins are mandatory for use in medical purposes we developed a convenient method for saponin isolation directly from the roots of Gypsophila paniculata L. The developed method is rapid, cheap and scaling up is also possible. By combining dialysis and HPLC three saponins were isolated in a one-step procedure. Chemical structures of the purified saponins were characterized by extensive one and two-dimensional NMR-spectroscopy and by using ESI-TOF-MS. The biological activities of the purified saponins were also investigated. The method presented herein enabled a rapid and cheap isolation of saponins for tumour therapy.     

Organ fusion and defective cuticle function in a lacs1 lacs2 double mutant of Arabidopsis

As the outermost layer on aerial tissues of the primary plant body, the cuticle plays important roles in plant development and physiology. The major components of the cuticle are cutin and cuticular wax, both of which are composed primarily of fatty acid derivatives synthesized in the epidermal cells. Long-chain acyl-CoA synthetases (LACS) catalyze the formation of long-chain acyl-CoAs and the Arabidopsis genome contains a family of nine genes shown to encode LACS enzymes. LACS2 is required for cutin biosynthesis, as revealed by previous investigations on lacs2 mutants. Here, we characterize lacs1 mutants of Arabidopsis that reveals a role for LACS1 in biosynthesis of cuticular wax components. lacs1 lacs2 double-mutant plants displayed pleiotropic phenotypes including organ fusion, abnormal flower development and reduced seed set; phenotypes not found in either of the parental mutants. The leaf cuticular permeability of lacs1 lacs2 was higher than that of either lacs1 or lacs2 single mutants, as determined by measurements of chlorophyll leaching from leaves immersed in 80% ethanol, staining with toluidine blue dye and direct measurements of water loss. Furthermore, lacs1 lacs2 mutant plants are highly susceptible to drought stress. Our results indicate that a deficiency in cuticular wax synthesis and a deficiency in cutin synthesis together have compounding effects on the functional integrity of the cuticular barrier, compromising the ability of the cuticle to restrict water movement, protect against drought stress and prevent organ fusion.     

A mutational analysis and molecular dynamics simulation of quinolone resistance proteins QnrA1 and QnrC from <Emphasis Type="Italic">Proteus mirabilis</Emphasis>

Background  

The first report on the transferable, plasmid-mediated quinolone-resistance determinant qnrA1 was in 1998. Since then, qnr alleles have been discovered worldwide in clinical strains of Gram-negative bacilli. Qnr proteins confer quinolone resistance, and belong to the pentapeptide repeat protein (PRP) family. Several PRP crystal structures have been solved, but little is known about the functional significance of their structural arrangement.     

Steroid hormones (17beta-estradiol and hydrocortisone) upregulate hepatocyte nuclear factor (HNF)-3beta and insulin-like growth factors I and II expression in the gonads of tilapia (Oreochromis mossambicus) in vitro

Hepatocyte nuclear factors (HNF-1alpha, -1beta and -3beta) and insulin-like growth factors (IGF-I and -II), which are involved in liver-specific gene expression, metabolism, development and cell growth, have been found in the gonads of tilapia (Oreochromis mossambicus). However, the functions of these factors and how they interact within the gonads of bony fish are not understood. In the present study, we provided experimental evidence that the expression of HNF-3beta in the gonads of tilapia, but not HNF-1alpha and -1beta, was affected in vitro by 17beta-estradiol and hydrocortisone. Immunohistochemical staining confirmed that tilapia HNF-3beta was mainly found in the nuclei of hepatocytes, the follicular granulosa cells of the ovaries, and the interstitial cells of the testes of adult tilapia. Further data were gathered at various steroid concentrations (0.1, 1, 10, 100, and 1000 nM) over various culture intervals (6, 12, 18, 24, 30, and 36 h) and subjected to semi-quantitative RT-PCR analysis. The expression of downstream genes (IGF-I and -II) followed the same temporal patterns as HNF-3beta, albeit at decreased levels for 30 and 36 h culture intervals. Both hormones upregulated HNF-3beta mRNA expression at concentrations of 0.1-10 nM, and reached optimal physiological concentrations for induction of IGFs at 1-10 nM. The identity of the PCR fragments was concurrently verified by sequencing and PCR-Southern hybridization. We inferred that HNF-3beta and IGFs may play a regulatory role in tilapia gonads during oocyte maturation and spermatogenesis.     

Insights on zinc regulation of food intake and macronutrient selection

Zinc (Zn) is an essential trace element required for human beings and animals. This divalent cation is involved in many physiological functions, including immune and antioxidant function, growth, and reproduction. Deficiency of Zn produces several pathological disorders and abnormalities in its metabolism, such as anorexia, weight loss, poor efficiency, and growth retardation. Although it has been known for more than 50 yr that Zn deficiency regularly and consistently causes anorexia in many animal species, the mechanism that causes this phenomenon still remains an enigma. The present review describes recent research investigating the relationship between Zn deficiency and the regulation of food intake, as well as macronutrient selection.     

ent-Abietane diterpenoids from Isodon rubescens var. rubescens

ent-Abietane diterpenoids, hebeiabinins A-F (1-5), together with seven known diterpenoids were isolated from leaves of Isodon rubescens var. rubescens. The structures of 1-5 were established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. The diterpenoids isolated were evaluated for the cytotoxicity against A549, HT-29, and K562 tumor cells. Compound 5 was the most active with IC(50) value of 0.91 microM against A549 cells.     

Bioimaging in the mid-infrared using an organometallic carbonyl tag

Two stable and water-soluble organometallic carbonyl cluster derivatives have been prepared and shown to enter the cell with ease. The CO stretching vibrations afford strong mid-infrared signals which have been demonstrated, for the first time, to be of utility in cell imaging via an IR microscope.     

Adaptation to stimulus contrast and correlations during natural visual stimulation

In this study, we characterize the adaptation of neurons in the cat lateral geniculate nucleus to changes in stimulus contrast and correlations. By comparing responses to high- and low-contrast natural scene movie and white noise stimuli, we show that an increase in contrast or correlations results in receptive fields with faster temporal dynamics and stronger antagonistic surrounds, as well as decreases in gain and selectivity. We also observe contrast- and correlation-induced changes in the reliability and sparseness of neural responses. We find that reliability is determined primarily by processing in the receptive field (the effective contrast of the stimulus), while sparseness is determined by the interactions between several functional properties. These results reveal a number of adaptive phenomena and suggest that adaptation to stimulus contrast and correlations may play an important role in visual coding in a dynamic natural environment.     

Gene expression of rat alveolar type II cells during hyperoxia exposure and early recovery

Alveolar epithelial cell (AEC) injury and repair during hyperoxia exposure and recovery have been investigated for decades, but the molecular mechanisms of these processes are not clear. To identify potentially important genes involved in lung injury and repair, we studied the gene expression profiles of isolated AEC II from control, 48-h hyperoxia-exposed (>95% O(2)), and 1-7 day recovering rats using a DNA microarray containing 10,000 genes. Fifty genes showed significant differential expression between two or more time points (P<0.05, fold change >2). These genes can be classified into 8 unique gene expression patterns. Real-time PCR verified 14 selected genes in three patterns related to hyperoxia exposure and early recovery. The change in the protein level for two of the selected genes, bmp-4 and retnla, paralleled that of the mRNA level. Many of these genes were found to be involved in cell proliferation and differentiation. In an in vitro AEC trans-differentiation culture model using AEC II isolated from control and 48-h hyperoxia-exposed rats, the expressions of the cell proliferation and differentiation genes identified above were consistent with their predicted roles in the trans-differentiation of AEC. These data indicate that a coordinated mechanism may control AEC differentiation during in vivo hyperoxia exposure and recovery as well as during in vitro AEC culture.