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101.
102.
MICHAEL R. THORPE ALEXANDRA C. U. FURCH PETER E. H. MINCHIN JENS FÖLLER AART J. E. VAN BEL JENS B. HAFKE 《Plant, cell & environment》2010,33(2):259-271
Phloem transport stops transiently within dicot stems that are cooled rapidly, but the cause remains unknown. Now it is known that (1) rapid cooling depolarizes cell membranes giving a transient increase in cytoplasmic Ca2+, and (2) a rise of free calcium triggers dispersion of forisomes, which then occlude sieve elements (SEs) of fabacean plants. Therefore, we compared the effects of rapid chilling on SE electrophysiology, phloem transport and forisomes in Vicia faba. Forisomes dispersed after rapid cooling with a delay that was longer for slower cooling rates. Phloem transport stopped about 20 s after forisome dispersion, and then transport resumed and forisomes re‐condensed within similar time frames. Transport interruption and forisome dispersion showed parallel behaviour – a cooling rate‐dependent response, transience and desensitization. Chilling induced both a fast and a slow depolarization of SE membranes, the electrical signature suggesting strongly that the cause of forisome dispersion was the transient promotion of SE free calcium. This apparent block of SEs by dispersed forisomes may be assisted by other Ca2+‐dependent sealing proteins that are present in all dicots. 相似文献
103.
MAHMOOD HASSAN KLAUS OLDACH UTE BAUMANN PETER LANGRIDGE TIM SUTTON 《Plant, cell & environment》2010,33(2):188-198
Boron tolerance is a quantitative trait controlled by multiple genes. Suppression subtractive hybridization was carried out on root cDNA from bulked boron tolerant and intolerant doubled haploid barley lines grown under moderate boron stress to identify genes associated with boron tolerance. One hundred and eleven clones representing known proteins were found to be up‐regulated in the tolerant bulk upon boron stress. Nine clones were genetically mapped to previously reported boron tolerance QTL. These include a clone identical to the boron transporter gene Bot1 and a clone coding for a bromo‐adjacent homology domain‐containing protein, mapping to the 6H boron tolerance locus and co‐segregating with reduced boron intake in a Clipper × Sahara‐3771 mapping population. A third clone mapping to the 2H QTL region encoding an S‐adenosylmethionine decarboxylase precursor was found to provide tolerance to high boron by heterologous expression. Yeast cells expressing Sahara SAMDC were able to grow on 15 mm boron solid media and maintained cellular boron concentrations at 13% lower than control cells expressing empty vector. The data suggest that an antioxidative response mechanism involving polyamines and the ascorbate–glutathione pathway in Sahara barley may provide an advantage in tolerating high soil concentrations of boron. 相似文献
104.
Mentalizing is the process by which we make sense of each other and ourselves,
implicitly and explicitly, in terms of subjective states and mental processes.
It is a profoundly social construct in the sense that we are attentive to
the mental states of those we are with, physically or psychologically. Given
the generality of this definition, most mental disorders will inevitably involve
some difficulties with mentalization, but it is the application of the concept
to the treatment of borderline personality disorder (BPD), a common psychiatric
condition with important implications for public health, that has received
the most attention. Patients with BPD show reduced capacities to mentalize,
which leads to problems with emotional regulation and difficulties in managing
impulsivity, especially in the context of interpersonal interactions. Mentalization
based treatment (MBT) is a time-limited treatment which structures interventions
that promote the further development of mentalizing. It has been tested in
research trials and found to be an effective treatment for BPD when delivered
by mental health professionals given limited additional training and with
moderate levels of supervision. This supports the general utility of MBT in
the treatment of BPD within generic mental health services.Borderline personality disorder (BPD) is a complex and serious mental disorder
characterized by a pervasive pattern of difficulties with emotion regulation
and impulse control, and instability both in relationships and in selfimage 1. It represents a serious public health problem,
because it is associated with suicide attempts and self harm, both of which
are consistent targets of mental health services. Recurrent suicidal behaviour
is reported in 69-80% of patients with BPD, and suicide rates are estimated
to be up to 10% 2. BPD is a common condition that is thought to occur globally with a prevalence
of 0.2-1.8% in the general population 3.
Higher prevalence rates are found in clinical populations. Moran et al 4 found a prevalence rate of 4-6% among primary
care attenders, suggesting that people with BPD are more likely to visit their
general practitioner. Chanen et al 5 reported
a prevalence rate of 11% in adolescent outpatients and 49% in adolescent inpatients.
The highest prevalence has been found in people requiring the most intensive
level of care, with a rate of 60-80% among patients in forensic services 6-7. The high prevalence and increased suicide rate in patients with BPD make
an unassailable argument that effective treatment needs to be developed and
that treatment has to be widely available. Whilst a number of treatments for
BPD have been shown to be moderately effective in randomized controlled trials,
it remains of considerable concern that most of them require extensive training,
making them unavailable to most patients. Mentalization based treatment (MBT)
was developed with this in mind. It requires relatively little additional
training on top of general mental health training, and has been implemented
in research studies by community mental health professionals, primarily nurses,
with limited training given modest levels of supervision. 相似文献
105.
Morphology of pollen and orbicules in some Dioscorea species and its systematic implications 总被引:2,自引:0,他引:2
PETER SCHOLS CAROL A. FURNESS PAUL WILKIN SUZY HUYSMANS ERIK SMETS FLS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,136(3):295-311
Pollen and orbicule morphology of 35 Dioscorea L. species is described based on observations with light microscopy, and scanning and transmission electron microscopy. Pollen and orbicule characters are critically evaluated and discussed in the context of existing hypotheses of systematic relationships within the genus. Pollen is mostly bisulcate (sometimes monosulcate) with a perforate, microreticulate or striate sexine. Our results indicate that pollen data may be significant at sectional rank. The close relationship between sections Asterotricha and Enantiophyllum proposed by Burkill and Ayensu is supported by pollen morphology as all species investigated share bisulcate, perforate pollen with small perforations and a high perforation density. Macromorphological differences between the two compound-leaved sections Botryosicyos and Lasiophyton are also supported by pollen morphology; pollens of these two sections have very different perforation patterns. Orbicules in Dioscorea are mostly spherical and possess a smooth or spinulose surface. The latter is often correlated with a striate sexine. 相似文献
106.
JULES ANGST THOMAS D. MEYER ROLF ADOLFSSON PETER SKEPPAR MAURO CARTA FRANCO BENAZZI RU‐BAND LU YI‐HSUAN WU HAI‐CHEN YANG CHENG‐MEI YUAN PAOLO MORSELLI PETER BRIEGER JUDITH KATZMANN INES ALICE TEIXEIRA LEÃO JOSÉ ALBERTO DEL PORTO DORIS HUPFELD MORENO RICARDO A. MORENO ODEILTON T. SOARES EDUARD VIETA ALEX GAMMA 《World psychiatry》2010,9(1):41-49
This study examined the transcultural robustness of a screening instrument
for hypomania, the Hypomania Checklist-32, first revised version (HCL-32 R1).
It was carried out in 2606 patients from twelve countries in five geographic
regions (Northern, Southern and Eastern Europe, South America and East Asia).
In addition, GAMIAN Europe contributed data from its members. Exploratory
and confirmatory factor analyses were used to examine the transregional stability
of the measurement properties of the HCL-32 R1, including the influence of
sex and age as covariates. Across cultures, a two-factor structure was confirmed:
the first factor (F1) reflected the more positive aspects of hypomania (being
more active, elated, self-confident, and cogni-tively enhanced); the second
factor (F2) reflected the more negative aspects (being irritable, impulsive,
careless, more substance use). The measurement properties of the HCL-32 R1
were largely invariant across cultures. Only few items showed transcultural
differences in their relation to hypomania as measured by the test. F2 was
higher among men and in more severe manic syndromes; F1 was highest in North
and East Europe and lowest in South America. The scores decreased slightly
with age. The frequency of the 32 items showed remarkable similarities across
geographic areas, with two excep-tions: South Europeans had lower symptom
frequencies in general and East Europeans higher rates of substance use. These
findings support the interna-tional applicability of the HCL-32 R1 as a screening
instrument for hypomania. 相似文献
107.
Mechanism of Mitochondrial Mutation in Yeast 总被引:2,自引:0,他引:2
THE yeast Saccharomyces cerevisiae can mutate to the respiratory-incompetent petite colony form. The mutation is probably caused by damage to, or loss of, the yeast's mitochondrial DNA, for petite mutants often lack mitochondrial DNA, possess it in abnormal amounts or with abnormal buoyant density1. Some of the agents, such as acrifiavine or ethidium bromide, which induce the petite mutation interfere with mitochondrial DNA synthesis2,3 whereas ethidium bromide also causes or permits degradation of Saccharomyces cerevisiae mitochondrial DNA2,3. We have observed that nalidixate (50 µg/ml.), an inhibitor of DNA synthesis, can prevent or delay petite mutation induced by ethidium bromide4. A similar effect has been observed by Hollenberg and Borst using a higher nalidixate concentration5. We have investigated the mechanism of this effect. A diploid prototrophic strain of Saccharomyces cerevisiae (NCYC 239) was used throughout. 相似文献
108.
JENNIFER L. STENGLEIN LISETTE P. WAITS DAVID E. AUSBAND PETER ZAGER CURT M. MACK 《The Journal of wildlife management》2010,74(5):1050-1058
ABSTRACT Traditional methods of monitoring gray wolves (Canis lupus) are expensive and invasive and require extensive efforts to capture individual animals. Noninvasive genetic sampling (NGS) is an alternative method that can provide data to answer management questions and complement already-existing methods. In a 2-year study, we tested this approach for Idaho gray wolves in areas of known high and low wolf density. To focus sampling efforts across a large study area and increase our chances of detecting reproductive packs, we visited 964 areas with landscape characteristics similar to known wolf rendezvous sites. We collected scat or hair samples from 20% of sites and identified 122 wolves, using 8–9 microsatellite loci. We used the minimum count of wolves to accurately detect known differences in wolf density. Maximum likelihood and Bayesian single-session population estimators performed similarly and accurately estimated the population size, compared with a radiotelemetry population estimate, in both years, and an average of 1.7 captures per individual were necessary for achieving accurate population estimates. Subsampling scenarios revealed that both scat and hair samples were important for achieving accurate population estimates, but visiting 75% and 50% of the sites still gave reasonable estimates and reduced costs. Our research provides managers with an efficient and accurate method for monitoring high-density and low-density wolf populations in remote areas. 相似文献
109.
ROGER A. HEWITT ANTONIO CHECA GERD E. G. WESTERMANN PETER M. ZABORSKI 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1991,24(3):271-287
Cretaceous Vascoceras and Jurassic Lytoceras show colour markings and etched surfaces representing original organic membranes between the septa. The main difference between the formation of ammonite and Nautilus chambers involved the continuous secretion of a gelatinous cameral liquid to support the ammonite mantle when it moved forward. The gel containing cyclically secreted membranes. here named pseudosepta, resembled the intra-cameral structures of the cuttlebone in Sepia. Pseudoscpta are attached to the shell wall in pseudosutures (Pseudoloben) which are particularly visible in the saddles of the septal suture and tend to mimic them. Their shape suggests reconstruction of posterior mantle shape during translocation. Drag-bands (Schleppstreifen) are spiral markings formed by the overlapping pseudosepta along the axial traces of the foliole folds. The chamber of ammonites was formed by a locally muscular mantle in a tripartite cycle: (1) the mantle initially remained attached to the saddles of the completed septal suture while muscular tissue within the umbilical lobes was contracted and rapidly reattached to the side of the lateral saddles; (2) the whole mantle subsequently crept forward by secreting a gelatinous matrix which contained telescoped membranes, with an adhesive function on pseudolobc flanks; (3) the mantle almost ceased to move within the sites of future lobules, but expanded and crept on before forming the mural and 'gutter' ridges of the septum. □ Ammonites, chamber growth, vascoceratids, LYTOCERAS, Nigeria. 相似文献
110.