Pycnogenol® and vitamin E inhibit ethanol‐induced apoptosis in rat cerebellar granule cells

Pycnogenol® (PYC), a patented combination of bioflavonoids extracted from the bark of French maritime pine (Pinus maritima), scavenges free radicals and promotes cellular health. The protective capacity of PYC against ethanol toxicity of neurons has not previously been explored. The present study demonstrates that in postnatal day 9 (P9) rat cerebellar granule cells the antioxidants vitamin E (VE) and PYC (1) dose dependently block cell death following 400, 800, and 1600 mg/dL ethanol exposure (2) inhibit the ethanol‐induced activation of caspase‐3 in the same model system; and (3) reduce neuronal membrane disruption as assayed by phosphatidylserine translocation to the cell surface. These results suggest that both PYC and VE have the potential to act as therapeutic agents, antagonizing the induction of neuronal cell death by ethanol exposure. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 261–271, 2004     

M89V Sialic Acid Acetyl Esterase (SIAE) and All Other Non-Synonymous Common Variants of This Gene Are Catalytically Normal

Catalytically defective rare variants of Sialic acid Acetyl Esterase (SIAE) have previously been linked to autoimmunity. Studies presented here confirm that the M89V SIAE protein and all other products of common variant alleles of SIAE are catalytically normal. Although overexpressing transfected non-lymphoid cells secrete small amounts of SIAE that can associate with the cell surface, normal human lymphocytes do not exhibit cell surface SIAE, supporting genetic evidence in mice that indicates that this protein functions in a lymphocyte intrinsic manner. Analyses of the plasma proteome also indicate that SIAE is not secreted in vivo. A re-analysis exclusively of catalytically defective rare variant alleles of SIAE in subjects in which this gene was completely sequenced confirmed an association of SIAE with autoimmunity. A subset of catalytically defective rare variant SIAE alleles has previously been typed in a large genotyping study comparing a diverse group of disease subjects and controls; our re-analysis of this data shows that catalytically defective alleles are enriched in disease subjects. These data suggest that SIAE may be associated with autoimmunity and that further study of catalytically defective rare variant SIAE alleles in terms of autoimmune disease susceptibility is strongly warranted.     

Solubilization of lignin by the ruminal anaerobic fungus Neocallimastix patriciarum.

The ability of the ruminal anaerobic phycomycete Neocallimastix patriciarum to digest model lignin compounds and lignified structures in plant material was studied in batch culture. The fungus did not degrade or transform model lignin compounds that were representative of the predominant intermonomer linkages in lignin, nor did it solubilize acid detergent lignin that had been isolated from spear grass. In a stem fraction of sorghum, 33.6% of lignin was apparently solubilized by the fungus. Solubilization of ester- and either-linked phenolics accounted for 9.2% of the lignin released. The amounts of free phenolic acids detected in culture fluid were equivalent to the apparent loss of ester-linked phenolics from the sorghum substrate. However, the fungus was unable to cleave the ether bond in hydroxycinnamic acid bridges that cross-link lignin and polysaccharide. It is suggested that the majority of the solubilized lignin fraction was a lignin carbohydrate complex containing ether-linked hydroxycinnamic acids. The lignin carbohydrate complex was probably solubilized through dissolution of xylan in the lignin-xylan matrix rather than by lignin depolymerization.     

Bioprocess development to produce a hyperthermostable S-methyl-5′-thioadenosine phosphorylase in Escherichia coli

Nucleoside phosphorylases are important biocatalysts for the chemo-enzymatic synthesis of nucleosides and their analogs which are, among others, used for the treatment of viral infections or cancer. S-methyl-5′-thioadenosine phosphorylases (MTAP) are a group of nucleoside phosphorylases and the thermostable MTAP of Aeropyrum pernix (ApMTAP) was described to accept a wide range of modified nucleosides as substrates. Therefore, it is an interesting biocatalyst for the synthesis of nucleoside analogs for industrial and therapeutic applications. To date, thermostable nucleoside phosphorylases were produced in shake flask cultivations using complex media. The drawback of this approach is low volumetric protein yields which hamper the wide-spread application of the thermostable nucleoside phosphorylases in large scale. High cell density (HCD) cultivations allow the production of recombinant proteins with high volumetric yields, as final optical densities >100 can be achieved. Therefore, in this study, we developed a suitable protocol for HCD cultivations of ApMTAP. Initially, optimum expression conditions were determined in 24-well plates using a fed-batch medium. Subsequently, HCD cultivations were performed using E. coli BL21-Gold cells, by employing a glucose-limited fed-batch strategy. Comparing different growth rates in stirred-tank bioreactors, cultivations revealed that growth at maximum growth rates until induction resulted in the highest yields of ApMTAP. On a 500-mL scale, final cell dry weights of 87.1–90.1 g L⁻¹ were observed together with an overproduction of ApMTAP in a 1.9%–3.8% ratio of total protein. Compared to initially applied shake flask cultivations with terrific broth (TB) medium the volumetric yield increased by a factor of 136. After the purification of ApMTAP via heat treatment and affinity chromatography, a purity of more than 90% was determined. Activity testing revealed specific activities in the range of 0.21 ± 0.11 (low growth rate) to 3.99 ± 1.02 U mg⁻¹ (growth at maximum growth rate). Hence, growth at maximum growth rate led to both an increased expression of the target protein and an increased specific enzyme activity. This study paves the way towards the application of thermostable nucleoside phosphorylases in industrial applications due to an improved heterologous expression in Escherichia coli.     

Cyclosporin A as prophylaxis against graft-versus-host disease in 36 patients.

Oral cyclosporin A was used as prophylaxis against graft-versus-host disease in (a) 31 patients with acute leukaemia or aplastic anaemia given transplants of HLA-matched bone marrow and (b) five patients with inborn errors of metabolism given transplants of haplotype-identical (parental) bone marrow. Twenty-six patients survived longer than two months after the operation. Despite the cyclosporin A, 31 patients (86%) suffered an acute form of graft-versus-host disease and 22 (61%) a chronic form. Nevertheless, the disease was usually treatable with immunosuppressive agents and caused the death of only one patient. Cyclosporin A caused renal toxicity in all cases; occasionally this was associated with a "capillary leak" syndrome, fatal in two patients. In children hypertension, fits, and fluid retention were common side effects. Blood concentrations of cyclosporin A correlated with blood urea values and blood pressure but did not predict the occurrence of graft-versus-host disease. Four different dose schedules were used to find the optimum way to administer this drug. Oral cyclosporin A is extremely effective at reducing the severity of graft-versus-host disease, but prevention of the disease is limited by toxicity of the drug and variable absorption. Better results might be achieved with parenteral administration or by using the drug in combination with other methods.     

Fulvestrant-Induced Cell Death and Proteasomal Degradation of Estrogen Receptor α Protein in MCF-7 Cells Require the CSK c-Src Tyrosine Kinase

Fulvestrant is a representative pure antiestrogen and a Selective Estrogen Receptor Down-regulator (SERD). In contrast to the Selective Estrogen Receptor Modulators (SERMs) such as 4-hydroxytamoxifen that bind to estrogen receptor α (ERα) as antagonists or partial agonists, fulvestrant causes proteasomal degradation of ERα protein, shutting down the estrogen signaling to induce proliferation arrest and apoptosis of estrogen-dependent breast cancer cells. We performed genome-wide RNAi knockdown screenings for protein kinases required for fulvestrant-induced apoptosis of the MCF-7 estrogen-dependent human breast caner cells and identified the c-Src tyrosine kinase (CSK), a negative regulator of the oncoprotein c-Src and related protein tyrosine kinases, as one of the necessary molecules. Whereas RNAi knockdown of CSK in MCF-7 cells by shRNA-expressing lentiviruses strongly suppressed fulvestrant-induced cell death, CSK knockdown did not affect cytocidal actions of 4-hydroxytamoxifen or paclitaxel, a chemotherapeutic agent. In the absence of CSK, fulvestrant-induced proteasomal degradation of ERα protein was suppressed in both MCF-7 and T47D estrogen-dependent breast cancer cells whereas the TP53-mutated T47D cells were resistant to the cytocidal action of fulvestrant in the presence or absence of CSK. MCF-7 cell sensitivities to fulvestrant-induced cell death or ERα protein degradation was not affected by small-molecular-weight inhibitors of the tyrosine kinase activity of c-Src, suggesting possible involvement of other signaling molecules in CSK-dependent MCF-7 cell death induced by fulvestrant. Our observations suggest the importance of CSK in the determination of cellular sensitivity to the cytocidal action of fulvestrant.     

Identification of QTLs controlling seed dormancy in peach (Prunus persica)

Dormancy is a condition that delays or inhibits growth in seed, vegetative buds, and floral buds. In peach, seed germination occurs when seed accumulate sufficient stratification and growing degree hours to break dormancy and begin growing. Correlations have been reported between mean seed stratification requirements and mean bud chilling requirements among Prunus families, but an individual seed’s germination date and subsequent vegetative and floral bud break date are not correlated. Prior to this study, the genetic factors involved in regulating seed dormancy and their location on the peach genomic map were unknown. Segregating F₂ seed were collected from a high?×?low chill F₁ peach hybrid in 2005, 2006, and 2008. Germination date and growth habit was measured after the stratification requirement of the 2005 seed was fully met. The seed collected in 2006 and 2008 received varying amounts of stratification, which enabled data on stratification requirement, heat requirement, and growth habit to be collected. Genomic DNA was extracted from seedling leaf tissue and screened with SSR markers selected from the Prunus reference map at an average resolution of 20 cM. Seed dormancy quantitative trait loci (QTLs) were detected on G1, G4, G6/8, and G7. The QTLs detected on G6/8 and G7 were discovered in the same region as QTLs associated with floral bud chilling requirement and bloom time in peach.     

Identification of the N-Terminal Domain of the Influenza Virus PA Responsible for the Suppression of Host Protein Synthesis

Cellular protein synthesis is suppressed during influenza virus infection, allowing for preferential production of viral proteins. To explore the impact of polymerase subunits on protein synthesis, we coexpressed enhanced green fluorescent protein (eGFP) or luciferase together with each polymerase component or NS1 of A/California/04/2009 (Cal) and found that PA has a significant impact on the expression of eGFP and luciferase. Comparison of the suppressive activity on coexpressed proteins between various strains revealed that avian virus or avian-origin PAs have much stronger activity than human-origin PAs, such as the one from A/WSN/33 (WSN). Protein synthesis data suggested that reduced expression of coexpressed proteins is not due to PA''s reported proteolytic activity. A recombinant WSN containing Cal PA showed enhanced host protein synthesis shutoff and induction of apoptosis. Further characterization of the PA fragment indicated that the N-terminal domain (PANt), which includes the endonuclease active site, is sufficient to suppress cotransfected gene expression. By characterizing various chimeric PANts, we found that multiple regions of PA, mainly the helix α4 and the flexible loop of amino acids 51 to 74, affect the activity. The suppressive effect of PANt cDNA was mainly due to PA-X, which was expressed by ribosomal frameshifting. In both Cal and WSN viruses, PA-X showed a stronger effect than the corresponding PANt, suggesting that the unique C-terminal sequences of PA-X also play a role in suppressing cotransfected gene expression. Our data indicate strain variations in PA gene products, which play a major role in suppression of host protein synthesis.