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1.
In winter 2000–2001, there was a serious outbreak of Gremmeniella abietina Morelet in southeastern Norway. During the outbreak, we noted that injured Scots pine trees (Pinus sylvestris L.) developed secondary buds in response to the fungus attack, and we decided to study the relationship between injury, appearance
of secondary buds and recovery of the trees thereafter. For this purpose, 143 trees from 10 to 50 years of age were chosen
and grouped into crown density classes. Injury was assessed in detail, and buds were counted before bud burst in the spring
of 2002. In addition, a subset of 15 trees was followed through the summer of 2002 to assess recovery. All injured trees developed
secondary buds, with a clear overweight of dormant winter buds in proportion to interfoliar buds. Healthy control trees did
not develop secondary buds at all. The secondary buds appeared predominantly on the injured parts of the tree; interfoliar
buds in particular developed just beneath the damaged tissue. Most of the secondary buds died during the winter of 2001–2002,
mainly because the fungus continued to spread after the first outbreak. Many of the remaining buds developed shoots with abnormal
growth during the summer. Secondary buds may help trees to recover from Gremmeniella attacks, but this strategy may fail when the fungus continues to grow and injure the newly formed buds and shoots. 相似文献
2.
Skin temperature increase caused by a mobile phone: a methodological infrared camera study 总被引:3,自引:0,他引:3
Mobile phone users often complain about burning sensations or a heating of the ear region. The increase in temperature may be due to thermal insulation by the phone, heating of the mobile phone resulting from its electrical power dissipation, and radio frequency (RF) exposure. The main objective of this study was to use infrared (IR) camera techniques to find how much each of these factors contributes to the increase in skin temperature resulting from the use of one GSM 900 phone. One subject, a healthy male, took part in the study. He was holding the phone in a normal position when the phone was switched off, when it was switched on but with the antenna replaced by a 50 Omega load to eliminate the RF exposure, and when it was transmitting RF fields. The output power could be fixed, and the minimal and the maximal power levels of the phone were used. The study was designed as a double blind experiment. The changes in temperature after 15 and 30 min of mobile phone use were calculated on the exposed side of the head relative to the unexposed side. The insulation and the electrical power dissipation led to statistically significant rises in the skin temperature, while the RF exposure did not. 相似文献
3.
The histidine protein kinase SppK is a peptide pheromone-activated kinase that regulates the production of the bacteriocin sakacin P in Lactobacillus sakei. SppK belongs to subfamily 10 of histidine protein kinases (HPKs), which regulate important processes in Gram-positive bacteria, including virulence, competence and bacteriocin production. To obtain insight into the functional properties of this relatively unknown class of HPKs, we have subjected SppK to random mutagenesis by error-prone PCR, followed by selection for mutants displaying a constitutive phenotype. Most identified mutations were clustered in a predicted coiled coil-like region, which is an important part of the HPK dimer interface and which includes the autophosphorylated histidine. Other mutations were located in the junctions between the dimerization domain and the membrane receptor domain or the catalytic kinase domain. Interestingly, two previously identified constitutive variants of ComD, an SppK homologue involved in competence regulation in Streptococcus pneumoniae, contained single mutations in the same regions. 相似文献
4.
Plant volatiles mediate attraction to host and non-host plant in apple fruit moth, Argyresthia conjugella 总被引:1,自引:0,他引:1
Marie Bengtsson Gunnhild Jaastad Geir Knudsen Sverre Kobro Anna-Carin Bäckman Eva Pettersson & Peter Witzgall 《Entomologia Experimentalis et Applicata》2006,118(1):77-85
Plant volatiles mediate host finding in insect herbivores and lead to host fidelity and habitat‐specific mating, generating premating reproductive isolation and facilitating sympatric divergence. The apple fruit moth, Argyresthia conjugella Zeller (Lepidoptera: Argyresthiidae), is a particularly suitable species to study the cues and behavioural mechanisms leading to colonization of a new host: it recurrently oviposits on the non‐host plant, apple Malus domestica Borkh. (Rosaceae), where the larvae cannot complete their development. The larval host of the apple fruit moth (Lepidoptera, Argyresthiidae), is rowan Sorbus aucuparia L. (Rosaceae). Fruit setting in rowan, however, fluctuates strongly over large areas in Scandinavia. Every 2–4 years, when too few rowanberries are available for egg laying in forests, apple fruit moth females oviposit instead on apple in nearby orchards, but not on other fruits, such as pear or plum. This poses the question of which cues mediate attraction to rowan and apple, and how apple fruit moth discriminates rowan from apple. Chemical analysis and antennal recordings showed that 11 out of 15 rowan volatiles eliciting an antennal response in A. conjugella females co‐occur in rowan and apple headspace, in a different proportion. In the field, A. conjugella was attracted to several of these plant volatiles, especially to 2‐phenyl ethanol, methyl salicylate, and decanal. Addition of anethole to 2‐phenyl ethanol had a strong synergistic effect, the 1 : 1 blend is a powerful attractant for A. conjugella males and females. These results confirm that volatiles common to both plants may account for a host switch in A. conjugella from rowan to apple. Some of the most attractive compounds, including 2‐phenyl ethanol, anethole, and decanal, which have been found in several apple cultivars, were not present in the headspace of the apple cultivar, Aroma, which is also susceptible to attack by A. conjugella. This supports the idea that the odour signal from apple is suboptimal for attraction of A. conjugella, but is nonetheless sufficient for attraction, during times when rowan is not available for egg laying. 相似文献
5.
Gunnhild Berdal Silje Halvorsen Désirée van der Heijde Morten Mowe Hanne Dagfinrud 《Arthritis research & therapy》2012,14(1):R19-10
Introduction
Pulmonary involvement is a known manifestation in patients with ankylosing spondylitis (AS). However, previous studies have been based on small samples and the reported prevalence and associations with typical clinical features vary. The purpose of this study was to compare pulmonary function (PF) in patients with AS and population controls, and to study associations between PF and disease related variables, cardio-respiratory fitness and demographic variables in patients with AS. 相似文献6.
The Gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus is the causal agent of bacterial wilt and ring rot of potato. So far, only two proteins have been shown to be essential for
virulence, namely a plasmid-encoded cellulase CelA and a hypersensitive response-inducing protein. We have examined the relative
expression of CelA and eight putative virulence factors during infection of potato and in liquid culture, using quantitative
real-time PCR. The examined putative virulence genes were celB, a cellulase-encoding gene and genes encoding a pectate lyase, a xylanase and five homologues of the Clavibacter michiganensis subsp. michiganensis pathogenicity factor Pat-1 thought to encode a serine protease. Six of the nine assayed genes were up-regulated during infection
of potato, including celA, celB, the xylanase gene, and two of the pat genes. The pectate lyase gene showed only slightly elevated expression, whereas three of the five examined pat genes were down-regulated during infection in potato. Interestingly, the two up-regulated pat genes showed a noticeable sequence
difference compared to the three down-regulated pat genes. These results reveal several new proteins that are likely to be
involved in Clavibacter michiganensis subsp. sepedonicus pathogenicity. 相似文献
7.
Gunnhild Jakobsen Morten Engstrøm Ørnulf Paulsen Karin Sjue Sunil X. Raj Morten Thronæs Marianne Jensen Hjermstad Stein Kaasa Peter Fayers Pål Klepstad 《Trials》2018,19(1):707
Background
Despite the high prevalence of insomnia in patients with advanced cancer, there are no randomized controlled trials on pharmacological interventions for insomnia in this group of patients. A variety of pharmacological agents is recommended to manage sleep disturbance for insomnia in the general population, but their efficacy and safety in adults with advanced cancer are not established. Thus, there is a need to evaluate the effectiveness of medications for insomnia in order to improve the evidence in patients with advanced cancer. One of the most used sleep medications at present in patients with cancer is zopiclone.Methods
This is a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. A total of 100 patients with metastatic cancer who report insomnia will be randomly allocated to zopiclone or placebo. The treatment duration with zopiclone/placebo is 6 consecutive nights. The primary endpoint is patient-reported sleep quality during the final study night (night 6) assessed on a numerical rating scale of 0–10, where 0?=?Best sleep and 10?=?Worst possible sleep. Secondary endpoints include the mean patient-reported total sleep time and sleep onset latency during the final study night (night 6).Discussion
Results from this study on treatment of insomnia in advanced cancer will contribute to clinical decision-making and improve the treatment of sleep disturbance in this patient cohort.Trial registration
ClinicalTrials.gov, NCT02807922. Registered on 21 June 2016.8.
9.
For trees, the ability to obtain and maintain sufficient levels of frost hardiness in late autumn, winter and spring is crucial.
We report that temperatures during dormancy induction influence bud set, frost hardiness, tolerance to cold storage, timing
of bud burst and spring frost hardiness in seedlings of Norway spruce (Picea abies (L.) Karst.). Bud set occurred later in 12°C than in 21°C, and later in cool nights (7°C) than in constant temperature. One
weekly frost night (−2.5°C) improved frost hardiness. Cool nights reduced frost hardiness early, but improved hardiness later
during cold acclimation. Buds and stems were slightly hardier in 21°C than in 12°C, while needles were clearly hardier in
12°C. Cold daytime temperature, cool nights and one weekly frost night improved cold storability (0.7°C). Seedlings receiving
high daytime temperatures burst buds later, and were less injured by light frost some days after bud burst. 相似文献
10.