Simultaneous Inhibition of Ethylene Biosynthesis and Binding Using AVG and 1-MCP in Two Rose Cultivars with Different Sensitivities to Ethylene

Journal of Plant Growth Regulation - The primary factors that determine the longevity of cut roses are variable and depend on a cultivar’s sensitivity to ethylene. The vase life of...     

Synthesis of double-layered rotavirus-like particles using internal ribosome entry site vector system in stably-transformed <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

We established a bicistronic expression system using an encephalomyocarditis virus (EMCV)-derived internal ribosomal entry site (IRES) element to generate stably transformed Drosophila melanogaster Schneider 2 (S2) cells expressing human rotavirus Wa capsid proteins, VP2 and VP6, for the synthesis of VP2/6 double-layered virus-like particle (DVLP). The EMCV-derived IRES permitted bicistronic translation of recombinant VP6. Recombinant VP2 and VP6 were detected in extracellular fractions of stably transformed S2 cells. A wheel-like DVLP (diam ~ 50–55 nm) with short spikes was produced from the extracellular fraction of stably transformed S2 cells. A bicistronic expression system using an EMCV-derived IRES element can thus be used to express two proteins of interest in stably transformed S2 cells. The bi-or tri-cistronic expression of recombinant VP2/6/7 using stably transformed S2 cells can also be used to produce rotavirus VLPs.     

Xylitol does not inhibit xylose fermentation by engineered <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> expressing <Emphasis Type="Italic">xylA</Emphasis> as severely as it inhibits xylose isomerase reaction in vitro

Efficient fermentation of xylose, which is abundant in hydrolysates of lignocellulosic biomass, is essential for producing cellulosic biofuels economically. While heterologous expression of xylose isomerase in Saccharomyces cerevisiae has been proposed as a strategy to engineer this yeast for xylose fermentation, only a few xylose isomerase genes from fungi and bacteria have been functionally expressed in S. cerevisiae. We cloned two bacterial xylose isomerase genes from anaerobic bacteria (Bacteroides stercoris HJ-15 and Bifidobacterium longum MG1) and introduced them into S. cerevisiae. While the transformant with xylA from B. longum could not assimilate xylose, the transformant with xylA from B. stercoris was able to grow on xylose. This result suggests that the xylose isomerase (BsXI) from B. stercoris is functionally expressed in S. cerevisiae. The engineered S. cerevisiae strain with BsXI consumed xylose and produced ethanol with a good yield (0.31 g/g) under anaerobic conditions. Interestingly, significant amounts of xylitol (0.23 g xylitol/g xylose) were still accumulated during xylose fermentation even though the introduced BsXI might not cause redox imbalance. We investigated the potential inhibitory effects of the accumulated xylitol on xylose fermentation. Although xylitol inhibited in vitro BsXI activity significantly (K _I = 5.1 ± 1.15 mM), only small decreases (less than 10%) in xylose consumption and ethanol production rates were observed when xylitol was added into the fermentation medium. These results suggest that xylitol accumulation does not inhibit xylose fermentation by engineered S. cerevisiae expressing xylA as severely as it inhibits the xylose isomerase reaction in vitro.     

RANKL induces NFATc1 acetylation and stability via histone acetyltransferases during osteoclast differentiation

The MTM (myotubularin)/MTMR (myotubularin-related) protein family is comprised of 15 lipid phosphatases, of which nine members are catalytically active. MTMs are known to play a fundamental role in human physiology as gene mutations can give rise to X-linked myotubular myopathy or Charcot-Marie-Tooth disease, which manifest in skeletal muscle or in peripheral neurons respectively. Interestingly, studies have shown MTMR2 and MTMR5, two MTM family members, to be highly expressed in the testis, particularly in Sertoli and germ cells, and knockout of either gene resulted in spermatogenic defects. Other studies have shown that MTMR2 functions in endocytosis and membrane trafficking. In the testis, MTMR2 interacts and co-localizes with c-Src/phospho-Src-(Tyr?1?), a non-receptor protein tyrosine kinase that regulates the phosphorylation state of proteins at the apical ES (ectoplasmic specialization), a unique type of cell junction found between Sertoli cells and elongating/elongated spermatids. In the present review, we highlight recent findings that have made a significant impact on our understanding of this protein family in normal cell function and in disease, with the emphasis on the role of MTMs and MTMRs in spermatogenesis. We also describe a working model to explain how MTMR2 interacts with other proteins such as c-Src, dynamin 2, EPS8 (growth factor receptor pathway substrate 8) and ARP2/3 (actin-related protein 2/3) at the apical ES and the apical TBC (tubulobulbar complex; tubular-like invaginations that function in the disassembly of the apical ES and in the recycling of its components) to regulate spermiation at late stage VIII of the seminiferous epithelial cycle.     

Aggression in pigtailed macaque (Macaca nemestrina) breeding groups affects pregnancy outcome

Past research has shown that aggressive behaviors can affect female reproductive outcome in nonhuman primate captive breeding programs. In this study, aggressive behaviors were recorded in a colony of pigtailed macaque monkeys (Macaca nemestrina) and related to pregnancy outcome. For 22 weeks, behavioral data were collected from nine breeding groups, consisting of zero to one male (some males were removed after a cycle of conceptions for husbandry reasons) and four to eight females. Observations included all occurrences of 11 aggressive behaviors during 15 min observation sessions, 1-3 times a week. Mean weekly aggression levels during the study period were determined for each group as well as for each pregnancy. Aggression data were summarized with Principal Components Analyses. Results indicate that pigtailed macaque aggression falls into five distinctive categories: warn, engage, threaten, pursue, and attack. Breeding groups differed in their levels of aggression, even after controlling for group size, presence of a sire, and group stability. Levels of the five aggression categories were found to affect the probability that a pregnancy ended in either a natural birth of a live infant, a clinical intervention producing a live infant, or a nonviable outcome. The predictive value of aggression was significant when clinical interventions were included as possible reproductive outcomes. Behavioral observation of captive groups could identify "risk" conditions affecting pregnancy outcome and the requirement for clinical intervention.     

Vascular-specific activity of the Arabidopsis carotenoid cleavage dioxygenase 7 gene promoter

Carotenoid cleavage dioxygenases (CCDs) are involved in the production of diverse apocarotenoids including phytohormones, the visual molecules and the aromatic volatile compounds derived from carotenoids. Here, we examined the spatial expression of four of the CCD genes (AtCcd1, 4, 7 and 8) among the nine members of this family in Arabidopsis by RT-PCR. We found that the AtCcd7 gene showed strong expression in seeds. However, the promoter activity of the 1,867-bp 5′-upstream region of this gene exhibited a vascular specificity at all developmental stages throughout the transgenic Arabidopsis plants tested. The strength of the AtCcd7 promoter was also found to be lower than that of the 35S promoter by about 60%. The whole body expression of the β-glucuronidase (GUS) reporter gene driven by the AtCcd7 promoter in Arabidopsis plants was confirmed in different organs by RT-PCR and GUS enzymatic assays. Histochemical GUS staining further revealed that the AtCcd7 promoter has utility in limiting the expression of target genes to the vascular tissues in all plant organs such as the leaf, stem, root, flower and seed.     

Novel enzymatic production of trehalose from sucrose using amylosucrase and maltooligosyltrehalose synthase-trehalohydrolase

Trehalose (α-d-glucopyranosyl α-d-glucopyranoside) is an important non-reducing disaccharide used in the food industry due to its mild sweetness (45% that of sucrose), low cariogenicity, high glass transition temperature, low hygroscopicity, and protein protection properties. In this study, we accomplished the production of trehalose from sucrose as a sole substrate using a novel dual-enzyme system, in which amylosucrase (ASase) and maltooligosyltrehalose synthase-trehalohydrolase (MTSH) fusion enzyme were employed. The biotransformation of sucrose to trehalose was confirmed by high-performance anion-exchange chromatography (HPAEC) analysis. Trehalose was successfully produced by both simultaneous and sequential methods by using ASase and MTSH. A higher trehalose production yield (3.15 ± 0.83 mM trehalose/20 mM sucrose) was observed in the sequential method than the simultaneous method (1.43 ± 0.14 mM trehalose/20 mM sucrose), indicating that the production of maltooligosaccharides from sucrose by ASase was an important step in the biosynthesis of trehalose.     

Synthesis and 11β hydroxysteroid dehydrogenase 1 inhibition of thiazolidine derivatives with an adamantyl group

A new series of thiazolidine derivatives with an adamantyl group was synthesized and evaluated for their ability to inhibit 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). Our initial compound 5a showed a weak inhibitory activity. Significant improvements in potency were achieved by substituent modification. The potent compound 8g (E) showed good in vitro inhibitory activity toward human 11β-HSD1, selectivity toward 11β-HSD2, metabolic stability, pharmacokinetic, and safety profile. Furthermore, this compound significantly inhibited 11β-HSD1 activity in rat and monkey models, and showed improved glycemic control in KKAy mice.