Anapleurosis is the filling of the tricarboxylic acid cycle with four-carbon units. The common substrate for both anapleurosis and glucose phosphorylation in bacteria is the terminal glycolytic metabolite phosphoenolpyruvate (PEP). Here we show that Escherichia coli quickly and almost completely turns off PEP consumption upon glucose removal. The resulting buildup of PEP is used to quickly import glucose if it becomes available again. The switch-like termination of anapleurosis results from depletion of fructose-1,6-bisphosphate (FBP), an ultrasensitive allosteric activator of PEP carboxylase. E. coli expressing an FBP-insensitive point mutant of PEP carboxylase grow normally when glucose is steadily available. However, they fail to build up PEP upon glucose removal, grow poorly when glucose availability oscillates and suffer from futile cycling at the PEP node on gluconeogenic substrates. Thus, bacterial central carbon metabolism is intrinsically programmed with ultrasensitive allosteric regulation to enable rapid adaptation to changing environmental conditions.

OBJECTIVE To extract the active component from the root of Actinidia valvata Dunn and to investigate the effects on hepatocellular carcinoma (HCC) cells in vitro. METHODS Total saponin was extracted from the root of A. valvata (TSAVD). HCC cells, such as BEL-7402, HepG2, PLC, SMMC-7721, MHCC-97-H, and MHCC-97-L, were treated with TSAVD in 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT) assay. BEL-7402 and MHCC-97-H cells were also treated respectively with TSAVD at different concentrations for 24 h in wound healing and adhesion assays, and the effects of TSAVD on BEL-7402 and MHCC-97-H cells mobility and adhesion abilities were observed. Meanwhile, the effects of TSAVD on invasion and migration of BEL-7402 and MHCC-97-H cells were also investigated by transwell chamber in invasion and migration assays. RESULTS TSAVD at 1.5 mg/mL inhibited BEL-7402 cell proliferation with inhibition ratios (IRs) of 61.08%, 74.12%, 84.55% at 24, 48, and 72 h, respectively. Meanwhile, TSAVD inhibited MHCC-97-H proliferation in a concentration-dependent manner from 1.5 to 0.5 mg/mL, with the IR of 36% at 1.5 mg/mL at 24 h. For SMMC-7721, PLC, and HepG2, the IR was lower than 30% at 1.5 mg/mL at 24 h. In the wound healing assay, mobility abilities of BEL-7402 and MHCC-97-H cells in TSAVD treated groups were significantly weaker than those of the control group. After pretreatment for 24 h with TSAVD, adhesion abilities were reduced in both MHCC-97-H and BEL-7402 cells, with IRs of 48.50%±4.86% and 49.85%±5.25% at 200 μg/mL. The IRs of MHCC-97-H and BEL-7402 cells in the migration assay were 49.13%±2.91% and 79.37%±0.09% at 200 μg/mL. In the invasion assay, IRs were 69.78%±4.88% and 82.48%±0.25% at 200 μg/mL. CONCLUSIONS Of all HCC cells, the highest inhibition by TSAVD was seen for BEL-7402 proliferation. TSAVD could restrain adhesion, invasion, mobility, and migration abilities of BEL-7402 and MHCC-97-H cells in vitro.

The mammalian target of rapamycin (mTOR) signaling pathway is upregulated in the pathogenesis of many cancers. Arachidonic acid (AA) and its metabolites play critical role in the development of breast cancer, but the mechanisms through which AA promotes mammary tumorigenesis and progression are poorly understood. We found that the levels of AA and cytosolic phospholipase A2 (cPLA2) strongly correlated with the signaling activity of mTORC1 and mTORC2 as well as the expression levels of vascular epithelial growth factor (VEGF) in human breast tumor tissues. In cultured breast cancer cells, AA effectively activated both mTOR complex 1 (mTORC1) and mTORC2. Interestingly, AA-stimulated mTORC1 activation was independent of amino acids, phosphatidylinositol 3-kinase (PI3-K) and tuberous sclerosis complex 2 (TSC2), which suggests a novel mechanism for mTORC1 activation. Further studies revealed that AA stimulated mTORC1 activity through destabilization of mTOR-raptor association in ras homolog enriched in brain (Rheb)-dependent mechanism. Moreover, we showed that AA-stimulated cell proliferation and angiogenesis required mTOR activity and that the effect of AA was mediated by lipoxygenase (LOX) but not cyclooxygenase-2 (COX-2). In animal models, AA-enhanced incidences of rat mammary tumorigenesis, tumor weights and angiogenesis were inhibited by rapamycin. Our findings suggest that AA is an effective intracellular stimulus of mTOR and that AA-activated mTOR plays critical roles in angiogenesis and tumorigenesis of breast cancer.Oncogene advance online publication, 20 February 2012; doi:10.1038/onc.2012.47.

Foot-and-mouth disease is a highly contagious and economically important disease of cloven-hoofed animals. RNA interference (RNAi) can be used as a rapid and specific antiviral approach. It was shown that treatment with recombinant adenovirus (Ad(VP1-2B)) carrying shRNAs targeted to the VP1 and 2B genes of FMDV expressed in tandem had marked antiviral effects against FMDV both in IBRS-2 cells and guinea pigs. Treatment with Ad(VP1-2B) both before and after FMDV infection was most effective in IBRS-2 cells, as the FMDV RNA transcripts could not be detected within 48 h post-challenge (hpc), and the viral RNA copy number at 72 hpc was only 0.02% of that in the positive control group. Delivery of Ad(VP1-2B) reduced significantly the susceptibility of guinea pigs to FMDV infection. All guinea pigs were protected within 3 days post challenge (dpc) when they were injected twice with the same dose of Ad(VP1-2B), and a third treatment with the same dose of Ad(VP1-2B) at 3 dpc was necessary to confer longer lasting protection (up to 6 dpc). In conclusion, application of such a adenovirus vector to inhibit more than one viral gene may be an advantageous method for prevention and therapy of FMDV infection.

Great efforts have been made in China to retrofit and upgrade the existing municipal wastewater treatment plants (WWTPs) for enhanced removal of organic substrates and in particular nutrients. However, the removal of trace recalcitrant or hazardous organic chemicals, e.g. steroid estrogens, one group of typical endocrine disrupting chemicals, has long been overlooked. The extensive investigations on estrogen removal rates in global and Chinese WWTPs and the estrogen biodegradation kinetics results in batch laboratory experiments are reviewed in this study. The effects of estrogen initial concentration and nitrifying activated sludge are highlighted. Challenges existing in current estrogen studies are pointed out, which are relevant for researches on fate and behavior of similar down-the-drain chemicals in both Chinese and global WWTPs.

This paper reports the results of a four-part questionnaire survey to assess the effects of the sound of dental equipment on people's perceptions and dental anxiety levels. The convenience sample for the survey comprised 230 dental students and 230 gender and age matched non-dental university students. The subjects were requested to complete the questionnaires themselves. The results show that the sound of dental equipment has a great influence on dental anxiety. Dental students, who are more familiar with the operation of this equipment, are less prone to anxiety when they hear its sound than their non-dental counterparts.

AIM To explore the role of actin-bundling protein, fascin during the progression of pancreatic cancer. METHODS The plasmid expressing human fascin-1 was stably transfected into the pancreatic cancer cell line MIA PaCa-2. The proliferation, cell cycle, motility, scattering, invasiveness and organization of the actin filament system in fascin-transfected MIA PaCa-2 cells and control non-transfected cells were determined. RESULTS Heterogeneous overexpression of fascin markedly enhanced the motility, scattering, and invasiveness of MIA PaCa-2 cells. However, overexpression of fascin had minimal effect on MIA PaCa-2 cell proliferation and cell cycle. In addition, cell morphology and organization of the actin filament system were distinctly altered in fascin overexpressed cells. When transplanted into BALB/c-nu mice, fascin-transfected pancreatic cancer cells developed solid tumors at a slightly slower rate, but these tumors displayed more aggressive behavior in comparison with control tumors. CONCLUSION Fascin promotes pancreatic cancer cell migration, invasion and scattering, thus contributes to the aggressive behavior of pancreatic cancer cells.

Calreticulin proteins play essential roles in regulating various metabolic processes and in molecular signal transduction in animals and plants. Using homologous PCR, we screened a cDNA library of the wheat resistance gene Yr5 from a near-isogenic line in the susceptible common wheat variety Taichung 29, which was inoculated with an incompatible race CYR32 of Puccinia striiformis. We isolated a novel full-length cDNA encoding calreticulin protein, which we named TaCRT1. Sequence analyses indicated that TaCRT1 contains an open reading frame of 1287 bp in length; it was deduced to encode 428 amino acids. Clustering analysis showed that TaCRT1 belongs to group III of the calreticulin protein family. Semi-quantitative RT-PCR was used to analyze expression profiles of the isolated gene under biotic and abiotic stresses. Expression of TaCRT1 was suppressed by exogenous application of phytohormones, such as abscisic acid and methyl jasmonate, and by dehydration; but it was induced by CYR32 infection and cold treatment. Based on the expression patterns, we propose that TaCRT1 participates in regulatory processes involved in defense responses and stress resistance in wheat.

BACKGROUND Abnormal distribution, modification and aggregation of transactivation response DNA-binding protein 43 (TDP-43) are the hallmarks of multiple neurodegenerative diseases, especially frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS). Researchers have identified 44 mutations in the TARDBP gene that encode TDP-43 as causative for cases of sporadic and familial ALS http://www.molgen.ua.ac.be/FTDMutations/. Certain mutant forms of TDP-43, such as M337V, are associated with increased low molecular weight (LMW) fragments compared to wild-type (WT) TDP-43 and cause neuronal apoptosis and developmental delay in chick embryos. Such findings support a direct link between altered TDP-43 function and neurodegeneration. RESULTS To explore the pathogenic properties of the M337V mutation, we generated and characterized two mouse lines expressing human TDP-43 (hTDP-43(M337V)) carrying this mutation. hTDP-43(M337V) was expressed primarily in the nuclei of neurons in the brain and spinal cord, and intranuclear and cytoplasmic phosphorylated TDP-43 aggregates were frequently detected. The levels of TDP-43 LMW products of ~25 kDa and ~35 kDa species were also increased in the transgenic mice. Moreover, overexpression of hTDP-43(M337V) dramatically down regulated the levels of mouse TDP-43 (mTDP-43) protein and RNA, indicating TDP-43 levels are tightly controlled in mammalian systems. TDP-43M337V mice displayed reactive gliosis, widespread ubiquitination, chromatolysis, gait abnormalities, and early lethality. Abnormal cytoplasmic mitochondrial aggregates and abnormal phosphorylated tau were also detected in the mice. CONCLUSION Our novel TDP-43M337V mouse model indicates that overexpression of hTDP-43(M337V) alone is toxic in vivo. Because overexpression of hTDP-43 in wild-type TDP-43 and TDP-43M337V mouse models produces similar phenotypes, the mechanisms causing pathogenesis in the mutant model remain unknown. However, our results suggest that overexpression of the hTDP-43(M337V) can cause neuronal dysfunction due to its effect on a number of cell organelles and proteins, such as mitochondria and TDP-43, that are critical for neuronal activity. The mutant model will serve as a valuable tool in the development of future studies designed to uncover pathways associated with TDP-43 neurotoxicity and the precise roles TDP-43 RNA targets play in neurodegeneration.

Successful crossbreeding between Oreochromis niloticus and Sarotherodon melanotheron to produce a commercial hybrid has been difficult. The karyotypes and isoenzyme of these two species and their reciprocal hybrids (O. niloticus female × S. melanotheron male, S. melanotheron female × O. niloticus male, the last not included in the isoenzyme study) were investigated via metaphase chromosomes obtained from head kidney cells and electropherogram of lactate dehydrogenase (LDH) isoenzymes from the liver, kidney, white muscle, heart, and eye balls. The diploid chromosome number (2n=44) and the fundamental number (NF=50) of the four tilapia genotypes were the same. However, the karyotype of O. niloticus had three pairs of sub-metacentric (sm), twelve pairs of sub-telocentric (st), and seven pairs of telocentric (t) chromosomes, while S. melanotheron had one pair of metacentric (m), two pairs of sm, 12 pairs of st, and seven pairs of t chromosomes. The reciprocal hybrids both showed a mixed karyotype range between their parents: 0.5 pair of m, 2.5 pairs of sm, 12 pairs of st, and seven pairs of t chromosomes. In view of the electropherogram of isozymes, only the LDH of the kidney showed significant clear bands, with five bands in O. niloticus, three bands in S. melanotheron, and duplicated six bands in the hybrids. The bands varied depending on their activities and mobilities. We considered that the differences in karyotype and isoenzyme were related to the genetic mechanism for post-mating isolation, and provided some additional basic genetic background of their taxonomy.