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121.
Water as an Essential Resource: Orb Web Spiders Cannot Balance Their Water Budget by Prey Alone 总被引:1,自引:0,他引:1
André Walter Natasha Cadenhead Valerie Sze Weii Lee Charlie Dove Emma Milley Mark A. Elgar 《Ethology : formerly Zeitschrift fur Tierpsychologie》2012,118(6):534-542
Water is essential for all living organisms because it acts as a major solvent and reaction medium. Terrestrial animals may lose water through evaporation and excretion and consequently have evolved strategies to balance their water budget by either minimising losses or by gaining water. The major pathway to gain water is via food intake, although many animals additionally drink free water. Spiders acquire substantial amounts of water by ingesting enzymatically liquefied prey. However, this may not account for the water needs of some species. We tested whether drinking is essential for orb web spiders of the genus Argiope by experimentally manipulating the diet (flies or crickets) and water supply (no water or a daily shower) to females and then measuring their subsequent drinking behaviour. Individuals of Argiope trifasciata, which are typically found in dry habitats, increased their body mass when fed crickets but not when fed flies. However, spiders deprived of water subsequently ingested significantly more water than spiders that received water every day, regardless of their feeding regime. This pattern was replicated in Argiope aetherea, which is found in the tropics and perhaps less likely to be water deprived in natural populations. Our results reveal that drinking allows these spiders to realise their water balance independent from the nutritional status. We suggest that the spiders may need to drink fresh water to process ingested nutrients. 相似文献
122.
Ratnam Wickneswari M. A. R. Bhuiyan Sabu Kalluvettankuzhy K. Li Sze Lim Michael J. Thomson Md. Kairudin Narimah Md. Zain Abdullah 《Plant Molecular Biology Reporter》2012,30(4):929-939
A backcross breeding strategy was used to identify quantitative trait loci (QTLs) associated with 14 traits in a BC2F2 population derived from a cross between MR219, an indica rice cultivar and an accession of Oryza rufipogon (IRGC 105491). A total of 261 lines were genotyped with 96 microsatellite markers and evaluated for plant morphology, yield components and growth period. The genetic linkage map generated for this population with an average interval size of 16.2?cM, spanning 1,553.4?cM (Kosambi) of the rice genome. Thirty-eight QTLs were identified with composite interval mapping (CIM), whereas simple interval mapping (SIM) resulted in 47 QTLs (LOD >3.0). The O. rufipogon allele was favourable for 59% of QTLs detected through CIM. Of 261 BC2F2 families, 26 advanced backcross breeding lines (BC2F5) were used for QTL validation. These lines were selected on the basis of the yield traits potentiality in BC2F3 and BC2F4 generations. The field trial was conducted at three different locations in Malaysia using randomized complete block design with three replications. Trait based marker analysis was done for QTL determination. Twenty-five QTLs were detected in BC2F5 generation whereas 29 QTLs were detected in BC2F2 generation of the same population. Two QTLs (qPL-1 and qSPL-7) were not considered for validation due to their low R 2 values and two QTLs (qPSS-3-2 and qGW-3-2) were not detected in the BC2F5 population. Fifteen QTLs showed the beneficial effect to enhance the trait value of the breeding lines. QTL validation aided to select the promising lines for further utilization. 相似文献
123.
Curcumin, an active constituent of turmeric, has been shown to possess inhibitory effect of cell proliferation and induction of apoptosis towards a board range of tumors. Cell inhibition activities of curcumin are behaved differently in various cell types. To investigate the mechanism basis for the cell inhibition of curcumin on breast cancer cell lines, we examine curcumin effect on NFκB, cell cycle regulatory proteins and matrix metalloproteinases (MMPs) in two breast cancer cell lines (MDA-MB-231 and BT-483). Cell proliferation was performed by water soluble tetrazolium WST-1 assay. The effect of curcumin's on the activity of matrix metalloproteinase-1, 3, 9 were analyzed by RT-PCR. Cell cycle regulatory protein including cyclin D1, CDK4 and p21 were examined by immunochemistry. The expressions of NFκB in breast cancer cells treated with curcumin were studied by immunochemistry and western blot. The results from WST-1 cell proliferation assay showed that curcumin exhibited the anti-proliferation effect on MDA-MB-231 and BT-483 cells in a time- and dose-dependent manner. In response to the treatment, while, the expression of cyclin D1 had declined in MDA-MB-231 and the expression of CDK4 in BT-483 had declined. MMP1 mRNA expression in BT-483 and MDA-MB-231 had significantly decreased in curcumin treatment group compared with control group. Our finding extrapolates the antitumor activity of curcumin in mediating the breast cancer cell proliferative rate and invasion by down-regulating the NFκB inducing genes. 相似文献
124.
Kim Hung Lam Roberto Gambari Marcus Chun Wah Yuen Chi Wai Kan Penni Chan Lijin Xu Weijun Tang Chung Hin Chui Gregory Yin Ming Cheng Raymond Siu Ming Wong Fung Yi Lau Cindy Sze Wai Tong Andrew Kit Wah Chan Paul Bo San Lai Stanton Hon Lung Kok Chor Hing Cheng Albert Sun Chi Chan Johnny Cheuk On Tang 《Bioorganic & medicinal chemistry letters》2009,19(8):2266-2269
A series of 2,6-dimethoxylpyridinyl phosphine oxides have been synthesized and examined for their antitumor activity. 2,6-Dimethoxy-3-phenyl-4-diphenylphosphinoylpyridine 2 has been employed as the lead compound for this study. We found out that the presence of phosphine oxide on the 2,6-dimethoxylpyridine ring is important for the antitumor activity; the presence of bromine on this core leads to a further enhancement of its antitumor activity. This is the first reported work on the antitumor activity of the 2,6-dimethoxy-3,5-dibromopyridinyl phosphine oxide 5b towards MDAMB-231 breast cancer and SKHep-1 hepatoma cell lines. 相似文献
125.
miR-200a-mediated downregulation of ZEB2 and CTNNB1 differentially inhibits nasopharyngeal carcinoma cell growth, migration and invasion 总被引:1,自引:0,他引:1
Hongping Xia Songshan Jiang Johnny Sze Hsiang-fu Kung Marie C. Lin 《Biochemical and biophysical research communications》2010,391(1):535-38
Nasopharyngeal carcinoma (NPC), a highly metastatic and invasive malignant tumor originating from the nasopharynx, is widely prevalent in Southeast Asia, the Middle East and North Africa. Although viral, dietary and genetic factors have been implicated in NPC, the molecular basis of its pathogenesis is not well defined. Based on a recent microRNA (miRNA) microarray study showing miR-200 downregulation in NPC, we further investigated the role of miR-200a in NPC carcinogenesis. We found that the endogenous miR-200a expression level increases with the degree of differentiation in a panel of NPC cell lines, namely undifferentiated C666-1, high-differentiated CNE-1, and low-differentiated CNE-2 and HNE1 cells. By a series of gain-of-function and loss-of-function studies, we showed that over-expression of miR-200a inhibits C666-1 cell growth, migration and invasion, whereas its knock-down stimulates these processes in CNE-1 cells. In addition, we further identified ZEB2 and CTNNB1 as the functional downstream targets of miR-200a. Interestingly, knock-down of ZEB2 solely impeded NPC cell migration and invasion, whereas CTNNB1 suppression only inhibited NPC cell growth, suggesting that the inhibitory effects of miR-200a on NPC cell growth, migration and invasion are mediated by distinct targets and pathways. Our results reveal the important role of miR-200a as a regulatory factor of NPC carcinogenesis and a potential candidate for miRNA-based therapy against NPC. 相似文献
126.
Andrey Kullyev Catherine M. Dempsey Sarah Miller Chih-Jen Kuan Vera M. Hapiak Richard W. Komuniecki Christine T. Griffin Ji Ying Sze 《Genetics》2010,186(3):929-941
Fluoxetine is one of the most commonly prescribed medications for many behavioral and neurological disorders. Fluoxetine acts primarily as an inhibitor of the serotonin reuptake transporter (SERT) to block the removal of serotonin from the synaptic cleft, thereby enhancing serotonin signals. While the effects of fluoxetine on behavior are firmly established, debate is ongoing whether inhibition of serotonin reuptake is a sufficient explanation for its therapeutic action. Here, we provide evidence of two additional aspects of fluoxetine action through genetic analyses in Caenorhabditis elegans. We show that fluoxetine treatment and null mutation in the sole SERT gene mod-5 eliminate serotonin in specific neurons. These neurons do not synthesize serotonin but import extracellular serotonin via MOD-5/SERT. Furthermore, we show that fluoxetine acts independently of MOD-5/SERT to regulate discrete properties of acetylcholine (Ach), gamma-aminobutyric acid (GABA), and glutamate neurotransmission in the locomotory circuit. We identified that two G-protein–coupled 5-HT receptors, SER-7 and SER-5, antagonistically regulate the effects of fluoxetine and that fluoxetine binds to SER-7. Epistatic analyses suggest that SER-7 and SER-5 act upstream of AMPA receptor GLR-1 signaling. Our work provides genetic evidence that fluoxetine may influence neuronal functions and behavior by directly targeting serotonin receptors.FLUOXETINE is a selective serotonin reuptake inhibitor (SSRI) and has made a major impact on the treatment of many behavioral disorders. The empirical action of SSRIs is blocking the serotonin reuptake transporter (SERT). SERT is localized in the plasma membrane and transports extracellular serotonin (5-HT) into the cytoplasm (Blakely et al. 1991; Hoffman et al. 1991), this being the major mechanism of terminating 5-HT signaling. Consequently, SSRIs are thought to exert therapeutic effects by blocking SERT from removal of 5-HT in the synaptic clef, thereby increasing the level of 5-HT signals (Schatzberg and Nemeroff 2004). However, several observations point to additional actions of SSRIs on the 5-HT system and neuronal functions. First, knockout of SERT in mouse caused a marked reduction of 5-HT in the brain (Bengel et al. 1998). Second, a variety of studies with cultured mammalian cells and mouse brain slices showed that SSRIs and tricyclic antidepressant agents (TCAs) have high affinities to many 5-HT receptor subtypes and act as agonists or antagonists depending on particular receptors being tested (Ni and Miledi 1997; Kroeze and Roth 1998; Eisensamer et al. 2003). Third, genetic analyses of the nematode Caenorhabditis elegans in our laboratory and others showed that fluoxetine and the TCA imipramine (Tofrani) could influence behavior independent of SERT function (Weinshenker et al. 1995; Ranganathan et al. 2001; Dempsey et al. 2005). In this study, we carried out a systematic survey of SSRIs treatment in C. elegans to gain new insights into actions of SSRIs on the 5-HT system and other neurotransmitter systems.In both vertebrates and invertebrates, 5-HT functions as a neuromodulator to either facilitate or inhibit synaptic transmission of other neurotransmitters (Fink and Gothert 2007). Modulation of synaptic activity by 5-HT signaling underscores the synaptic plasticity involved in stress responses, learning, adaptation, and memory (Kandel 2001; Zhang et al. 2005). The role of 5-HT in C. elegans was initially identified through pharmacological experiments showing that exogenous 5-HT can promptly induce changes in a variety of behaviors, including feeding, egg laying, and locomotion (Avery and Horvitz 1990; Weinshenker et al. 1995; Nurrish et al. 1999). The relevance of these behaviors to endogenous 5-HT has since been validated through studies of mutants of 5-HT signaling. Importantly, multiple 5-HT receptors may function in distinct cells synergistically or antagonistically to regulate a specific behavior (Carnell et al. 2005; Dernovici et al. 2007; Murakami and Murakami 2007; Hapiak et al. 2009). In nearly all tested paradigms, fluoxetine and imipramine induce behavioral changes similarly to exogenous 5-HT (Weinshenker et al. 1995; Nurrish et al. 1999), implying that fluoxetine regulates 5-HT inputs to these neural circuits. However, the tryptophan hydroxylase gene tph-1 is required for 5-HT biosynthesis in C. elegans (Sze et al. 2000), mod-5 encodes its sole SERT (Ranganathan et al. 2001), and yet fluoxetine could stimulate egg laying and inhibit locomotion in mod-5 and tph-1 mutants (Weinshenker et al. 1995; Choy and Thomas 1999; Ranganathan et al. 2001; Dempsey et al. 2005). These findings provided a basis for further investigation into genes and synaptic functions regulated by 5-HT and the impact of fluoxetine on 5-HT signaling.Here we present genetic evidence of multifaceted effects of fluoxetine on the 5-HT system and its downstream targets in C. elegans. We show that fluoxetine treatment and loss of MOD-5/SERT function do not simply increase presynaptic 5-HT signals. Rather, they may eliminate 5-HT in specific neurons. Furthermore, fluoxetine acts independently of SERT to regulate 5-HT serotonin receptors and their downstream targets involved in acetylcholine (ACh), gamma-aminobutyric acid (GABA), and glutamate neurotransmission. 相似文献
127.
Wang J Ding Y Wang J Hillmer S Miao Y Lo SW Wang X Robinson DG Jiang L 《The Plant cell》2010,22(12):4009-4030
The exocyst protein complex mediates vesicle fusion with the plasma membrane. By expressing an (X)FP-tagged Arabidopsis thaliana homolog of the exocyst protein Exo70 in suspension-cultured Arabidopsis and tobacco (Nicotiana tabacum) BY-2 cells, and using antibodies specific for Exo70, we detected a compartment, which we term EXPO (for exocyst positive organelles). Standard markers for the Golgi apparatus, the trans-Golgi network/early endosome, and the multivesicular body/late endosome in plants do not colocalize with EXPO. Inhibitors of the secretory and endocytic pathways also do not affect EXPO. Exo70E2-(X)FP also locates to the plasma membrane (PM) as discrete punctae and is secreted outside of the cells. Immunogold labeling of sections cut from high-pressure frozen samples reveal EXPO to be spherical double membrane structures resembling autophagosomes. However, unlike autophagosomes, EXPOs are not induced by starvation and do not fuse with the lytic compartment or with endosomes. Instead, they fuse with the PM, releasing a single membrane vesicle into the cell wall. EXPOs are also found in other cell types, including root tips, root hair cells, and pollen grains. EXPOs therefore represent a form of unconventional secretion unique to plants. 相似文献
128.
Mc Guire C Volckaert T Wolke U Sze M de Rycke R Waisman A Prinz M Beyaert R Pasparakis M van Loo G 《Journal of immunology (Baltimore, Md. : 1950)》2010,185(12):7646-7653
Apoptosis of oligodendrocytes (ODCs), the myelin-producing glial cells in the CNS, plays a central role in demyelinating diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. To investigate the mechanism behind ODC apoptosis in EAE, we made use of conditional knockout mice lacking the adaptor protein FADD specifically in ODCs (FADD(ODC-KO)). FADD mediates apoptosis by coupling death receptors with downstream caspase activation. In line with this, ODCs from FADD(ODC-KO) mice were completely resistant to death receptor-induced apoptosis in vitro. In the EAE model, FADD(ODC-KO) mice followed an ameliorated clinical disease course in comparison with control littermates. Lymphocyte and macrophage infiltration into the spinal cord parenchyma was significantly reduced, as was the extent of demyelination and proinflammatory gene expression. Collectively, our data show that FADD is critical for ODC apoptosis and the development of autoimmune demyelinating disease. 相似文献
129.
Guanghou Shui Xue Li Guan Pradeep Gopalakrishnan Yangkui Xue Joyce Sze Yuin Goh Hongyuan Yang Markus R. Wenk 《PloS one》2010,5(8)
Background
Phosphatidic acid (PA) is a key regulated intermediate and precursor for de novo biosynthesis of all glycerophospholipids. PA can be synthesized through the acylation of lysophosphatidic acid (LPA) by 1-acyl-3-phosphate acyltransferase (also called lysophosphatidic acid acyltransferase, LPAAT). Recent findings have substantiated the essential roles of acyltransferases in various biological functions.Methodologies/Principal Findings
We used a flow-injection-based lipidomic approach with ∼200 multiple reaction monitoring (MRM) transitions to pre-screen fatty acyl composition of phospholipids in the yeast Saccharomyces cerevisiae mutants. Dramatic changes were observed in fatty acyl composition in some yeast mutants including Slc1p, a well-characterized LPAAT, and Cst26p, a recently characterized phosphatidylinositol stearoyl incorporating 1 protein and putative LPAAT in S. cerevisiae. A comprehensive high-performance liquid chromatography–based multi-stage MRM approach (more than 500 MRM transitions) was developed and further applied to quantify individual phospholipids in both strains to confirm these changes. Our data suggest potential fatty acyl substrates as well as fatty acyls that compensate for defects in both Cst26p and Slc1p mutants. These results were consistent with those from a non-radioactive LPAAT enzymatic assay using C17-LPA and acyl-CoA donors as substrates.Conclusions
We found that Slc1p utilized fatty acid (FA) 18:1 and FA 14:0 as substrates to synthesize corresponding PAs; moreover, it was probably the only acyltransferase responsible for acylation of saturated short-chain fatty acyls (12:0 and 10:0) in S. cerevisiae. We also identified FA 18:0, FA 16:0, FA 14:0 and exogenous FA 17:0 as preferred substrates for Cst26p because transformation with a GFP-tagged CST26 restored the phospholipid profile of a CST26 mutant. Our current findings expand the enzymes and existing scope of acyl-CoA donors for glycerophospholipid biosynthesis. 相似文献130.
Recent studies have indicated that the relaxation rate of the 1H-13C multiple-quantum coherence is much slower than that of the 1H-13C single-quantum coherence for non-aromatic methine sites in 13 C labeled proteins and in nucleic acids at the slow tumbling limit. Several heteronuclear experiments have been designed to use a multiple-quantum coherence transfer scheme instead of the single-quantum transfer method, thereby increasing the sensitivity and resolution of the spectra. Here, we report a constant time, gradient and sensitivity enhanced HMQC experiment (CT-g/s-HMQC) and demonstrate that it has a significant sensitivity enhancement over constant time HMQC and constant time gradient and sensitivity enhanced HSQC experiments (CT-g/s-HSQC) when applied to a 13C and 15 N labeled calmodulin sample in D2O. We also apply this approach to 3D NOESY-HMQC and doubly sensitivity enhanced TOCSY-HMQC experiments, and demonstrate that they are more sensitive than their HSQC counterparts. 相似文献