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971.
Lin Kooi Ong Larisa Bobrovskaya Frederick R. Walker Trevor A. Day Phillip W. Dickson Peter R. Dunkley 《Neurochemical research》2011,36(1):27-33
Tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis, is regulated acutely by protein phosphorylation
and chronically by protein synthesis. No studies have systematically investigated the phosphorylation of these sites in vivo
in response to stressors. We specifically investigated the phosphorylation of TH occurring within the first 24 h in response
to the social defeat stress in the rat adrenal, the locus coeruleus, substantia nigra and ventral tegmental area. Five groups
were investigated; home cage control (HCC), two groups that underwent social defeat (SD+) which were sacrificed either 10 min
or 24 h after the end of the protocol and two groups that were put into the cage without the resident being present (SD−)
which were sacrificed at time points identical to the SD+. We found at 10 min there were significant increases in serine 40
and 31 phosphorylation levels in the locus coeruleus in SD+ compared to HCC and increases in serine 40 phosphorylation levels
in the substantia nigra in SD+ compared to SD−. We found at 24 h there were significant increases in serine 19 phosphorylation
levels in the ventral tegmental area in SD+ compared to HCC and decreases in serine 40 phosphorylation levels in the adrenal
in SD+ compared to SD−. These findings suggest that the regulation of TH phosphorylation in different catecholamine-producing
cells varies considerably and is dependent on both the nature of the stressor and the time at which the response is analysed. 相似文献
972.
Michael?Gomez?Selvaraj Gloria?Burow John?J.?Burke Vikas?Belamkar Naveen?Puppala Mark?D.?BurowEmail author 《Plant Growth Regulation》2011,65(1):83-91
Heat can be one of the major abiotic stresses that adversely affect crop production worldwide at different stages of development.
As field screening for heat tolerance can be inconsistent and seasonally-limited, it is important to develop a reliable protocol
under controlled conditions that allows simultaneous screening of multiple genotypes. The objective of this research was to
develop a straightforward laboratory protocol using acquired thermotolerance (ATT) in peanut seedlings as a measure of one
mechanism of heat stress tolerance. Sixteen genotypes, including selected accessions of the US peanut minicore collection
along with standard checks, were evaluated for acquired themotolerance in two independent experiments. A change in the temperature
sensitivity of chlorophyll accumulation was used as an indicator of acquired thermotolerance. Pre-incubation at 38°C for 4 h
before the 30-min 50°C challenge triggered the acquired thermotolerance system of the leaf disks, resulting in chlorophyll
accumulation upon exposure to light. There was considerable variation among genotypes for ATT in both experiments. Genotypic
ranking for mean ATT values were highly correlated (0.949) in both experiments. The effect of seed weight on ATT was not significant.
This method is relatively simple and inexpensive and can be used to screen a large number of genotypes. 相似文献
973.
Phillip A. Wadl Adam J. Dattilo Lisa M. Vito Robert N. Trigiano 《Plant Cell, Tissue and Organ Culture》2011,106(3):513-516
Pityopsis ruthii is an endangered herbaceous perennial species from the United States. In vitro multiplication of this species can be valuable
for germplasm conservation. Flower receptacles of P. ruthii were cultured on Murashige and Skoog medium (MS) supplemented with 11.4 μM indole-3-acetic acid (IAA) in combination with
2.2, 4.4 or 8.8 μM 6-benzyladenine (BA). Shoots were visible within 14–28 days and three plants were successfully rooted on
MS medium supplemented with 5.7 μM IAA. A two tailed t-test for paired-variates revealed that shoot regeneration on MS medium
amended with 11.4 μM IAA and 2.2 μM BA was significantly higher (P < 0.05) than on other treatments. Leaf explants were also cultured on MS not supplemented with growth regulators or supplemented
with 11.4 μM IAA in combination with 0, 2.2, 4.4 or 8.8 μM BA. Shoots were visible within 21–35 days and one plant was successfully
rooted on MS medium supplemented with 5.4 μM NAA. Shoot regeneration on MS medium augmented with 11.4 μM IAA and 2.2 μM BA
was significantly higher (P < 0.05) than the other treatments according to analysis of variance (ANOVA) with a rank transformation. Hyperhydricity and
rooting of shoots was problematic for explants derived from flower receptacles and leaf tissue, but viable plants were regenerated
using both explants sources indicating the potential role for micropropagation in the ex situ conservation of the species. 相似文献
974.
Kim I. Currie Gordon Brailsford Sylvia Nichol Antony Gomez Rodger Sparks Keith R. Lassey Katja Riedel 《Biogeochemistry》2011,104(1-3):5-22
Measurements of near-sea-level tropospheric ??14CO2 have been made at Wellington, New Zealand since December 1954; these measurements comprise the longest such record available. The ??14C rose from ?10?? in 1955 peaking at 695?? in 1965 as a result of ??bomb 14C?? production, before falling thereafter to the present day (2005) value of 73??. The ??14C peak occurred about 1?year later in the southern hemisphere than in the northern hemisphere. The post-1965 fall is due to the transfer of 14C-enriched CO2 to the biospheric and oceanic pools together with ongoing release of 14C-free CO2 from fossil fuel combustion, during an era without major atmospheric nuclear-weapon tests. Time series analysis of the data using Loess decomposition and filtering indicates an approximately exponential decline in excess ??14CO2 over 1967?C2005 with an e-folding time of 18?years. The seasonal cycle from 1954 until 1980 had a maximum in the late (austral) summer, a minimum in winter, with peak-to-trough amplitude that peaked at 20?? in 1966. For the period 1980?C1989, a new seasonal cycle emerged, with a maximum in winter and a minimum in late summer/early autumn and peak-to-trough amplitude of 3.5??, transitioning to a new seasonal structure after about 1990. 相似文献
975.
Three isolates (AL09-71, AL09-72, and AL09-73) of Aeromonas hydrophila were cultured from infected channel catfish Ictalurus punctatus during a disease outbreak in west Alabama, USA, in August 2009. Sequence analysis of the 16S-23S rDNA intergenic spacer region (ISR), cpn60, gyrB, and rpoD genes of the 3 strains revealed that the 3 strains were closely related to each other, sharing 97 to 99% nucleotide sequence similarities. However, ISR sequences of the 3 isolates from 2009 shared only 64% nucleotide sequences with AL98-C1B, a 1998 isolate of A. hydrophila cultured from diseased fish in Alabama. Sequences of cpn60, gyrB, and rpoD from the 3 isolates from 2009 shared 91 to 95% homologies with AL98-C1B. Based on both LD50 and LD95 values of intraperitoneal injection assays, the virulences of the 3 isolates from 2009 were not significantly different from each other, but were at least 200-fold more virulent than AL98-C1B, indicating that the 3 west Alabama isolates of A. hydrophila from 2009 were highly virulent to channel catfish. 相似文献
976.
Woods A Heslegrave AJ Muckett PJ Levene AP Clements M Mobberley M Ryder TA Abu-Hayyeh S Williamson C Goldin RD Ashworth A Withers DJ Carling D 《The Biochemical journal》2011,434(1):49-60
LKB1 is a 'master' protein kinase implicated in the regulation of metabolism, cell proliferation, cell polarity and tumorigenesis. However, the long-term role of LKB1 in hepatic function is unknown. In the present study, it is shown that hepatic LKB1 plays a key role in liver cellular architecture and metabolism. We report that liver-specific deletion of LKB1 in mice leads to defective canaliculi and bile duct formation, causing impaired bile acid clearance and subsequent accumulation of bile acids in serum and liver. Concomitant with this, it was found that the majority of BSEP (bile salt export pump) was retained in intracellular pools rather than localized to the canalicular membrane in hepatocytes from LLKB1KO (liver-specific Lkb1-knockout) mice. Together, these changes resulted in toxic accumulation of bile salts, reduced liver function and failure to thrive. Additionally, circulating LDL (low-density lipoprotein)-cholesterol and non-esterified cholesterol levels were increased in LLKB1KO mice with an associated alteration in red blood cell morphology and development of hyperbilirubinaemia. These results indicate that LKB1 plays a critical role in bile acid homoeostasis and that lack of LKB1 in the liver results in cholestasis. These findings indicate a novel key role for LKB1 in the development of hepatic morphology and membrane targeting of canalicular proteins. 相似文献
977.
McCullough DG Poland TM Anulewicz AC Lewis P Cappaert D 《Journal of economic entomology》2011,104(5):1599-1612
Effective methods are needed to protect ash trees (Fraxinus spp.) from emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive buprestid that has killed millions of North American ash (Fraxinus spp.) trees. We randomly assigned 175 ash trees (11.5-48.1 cm in diameter) in 25 blocks located in three study sites in Michigan to one of seven insecticide treatments in May 2007. Treatments included 1) trunk-injected emamectin benzoate; 2) trunk-injected imidacloprid; 3) basal trunk spray of dinotefuran with or 4) without Pentra-Bark, an agricultural surfactant; 5) basal trunk spray of imidacloprid with or 6) without Pentra-Bark; or (7) control. Foliar insecticide residues (enzyme-linked immunosorbent assay) and toxicity of leaves to adult A. planipennis (4-d bioassays) were quantified at 3-4-wk intervals posttreatment. Seven blocks of trees were felled and sampled in fall 2007 to quantify A. planipennis larval density. Half of the remaining blocks were retreated in spring 2008. Bioassays and residue analyses were repeated in summer 2008, and then all trees were sampled to assess larval density in winter. Foliage from emamectin benzoate-treated trees was highly toxic to adult A. planipennis, and larval density was < 1% of that in comparable control trees, even two seasons posttreatment. Larval densities in trees treated with trunk-injected imidacloprid in 2007 + 2008 were similar to control trees. Dinotefuran and imidacloprid were effectively translocated within trees treated with the noninvasive basal trunk sprays; the surfactant did not appreciably enhance A. planipennis control. In 2008, larval densities were 57-68% lower in trees treated with dinotefuran or imidacloprid trunk sprays in 2007 + 2008 than on controls, but densities in trees treated only in 2007 were similar to controls. Highly effective control provided by emamectin benzoate for > or = 2 yr may reduce costs or logistical issues associated with treatment. 相似文献
978.
Pitzer JB Kaufman PE Hogsette JA Geden CJ Tenbroeck SH 《Journal of economic entomology》2011,104(3):1108-1115
Beginning in November 2007 and continuing until December 2009, weekly stable fly, Stomoxys calcitrans (L.), surveillance was conducted at four equine facilities near Ocala, FL, by using alsynite sticky traps for adults and by searching immature developmental sites for pupae. Adult stable fly trap captures were highly variable throughout the year, ranging from 0 to 1,400 flies per trap per farm. The greatest adult stable fly activity was observed during the spring months of March and April, with weekly three-trap means of 121 and 136 flies per farm, respectively. The importance of cultural control measures was most apparent on the only farm with no reported insecticide use and the lowest stable fly trap captures, where an intense daily sanitation and composting program was conducted. A survey of on-site filth fly pupae revealed that 99.9% of all parasitoids recovered were Spalangia spp., consisting of Spalangia cameroni Perkins (56.5%), Spalangia nigroaenea Curtis (34.0%), Spalangia endius Walker (5.8%), and Spalangia nigra Latreille (3.7%). The implications of these findings are discussed. 相似文献
979.
The insect sodium channel is of particular interest for evaluating resistance to pyrethroids because it is the target molecule for this major class of neurotoxic insecticides. The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), sodium channel coding sequence representing domains IS6 through IVS6 was isolated, and the sequence encoding domain II was compared among individuals of a laboratory strain selected for resistance to permethrin and the unselected, parental generation. A point mutation resulting in a leucine-to-histidine amino acid change was identified (Leul014His), and its location corresponded with that observed for knockdown resistance (kdr) mutations in other insects. As a result, the allele was designated kdr-his. A molecular assay was developed to assess the frequency of this mutation in genomic DNA of individual stable flies from the laboratory selections, which provided further evidence that the kdr-his allele accounts for the observed level ofpermethrin resistance in the selected strain. The assay was then used to evaluate the frequency of the mutation from five field-collected populations originating from three horse farms near Ocala, FL; one horse farm near Gainesville, FL; and one dairy farm near Hague, FL. Frequency of the kdr-his allele ranged from 0.46 to 0.78, supporting further investigation of allele prevalence throughout the stable fly season and in response to field insecticide application. 相似文献
980.