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31.
32.
Shlomit Jacobson-Pick Marie-Claude Audet Robyn Jane McQuaid Rahul Kalvapalle Hymie Anisman 《PloS one》2013,8(4)
Stressful events promote several neuroendocrine and neurotransmitter changes that might contribute to the provocation of psychological and physical pathologies. Perhaps, because of its apparent ecological validity and its simple application, there has been increasing use of social defeat (resident-intruder) paradigms as a stressor. The frequency of stress-related psychopathology is much greater in females than in males, but the typical resident-intruder paradigm is less useful in assessing stressor effects in females. An alternative, but infrequently used procedure in females involves exposing a mouse to a lactating dam, resulting in threatening gestures being expressed by the resident. In the present investigation we demonstrated the utility of this paradigm, showing that the standard resident-intruder paradigm in males and the modified version in females promoted elevated anxiety in a plus-maze test. The behavioral effects that reflected anxiety were more pronounced 2 weeks after the stressor treatment than they were 2 hr afterward, possibly reflecting the abatement of the stress-related of hyper-arousal. These treatments, like a stressor comprising physical restraint, increased plasma corticosterone and elicited variations of norepinephrine and serotonin levels and turnover within the prefrontal cortex, hippocampus and central amygdala. Moreover, the stressor effects were exaggerated among mice that had been exposed to a chronic or subchronic-intermittent regimen of unpredictable stressors. Indeed, some of the monoamine changes were more pronounced in females than in males, although it is less certain whether this represented compensatory changes to deal with chronic stressors that could result in excessive strain on biological systems (allostatic overload). 相似文献
33.
Jeremias C. Zill Zhihui He Marcus Tank Bryan H. Ferlez Daniel P. Canniffe Yigal Lahav Peter Bellstedt A. Alia Igor Schapiro John H. Golbeck Donald A. Bryant Jörg Matysik 《Photosynthesis research》2018,137(2):295-305
Photochemically induced dynamic nuclear polarization (photo-CIDNP) has been observed in the homodimeric, type-1 photochemical reaction centers (RCs) of the acidobacterium, Chloracidobacterium (Cab.) thermophilum, by 15N magic-angle spinning (MAS) solid-state NMR under continuous white-light illumination. Three light-induced emissive (negative) signals are detected. In the RCs of Cab. thermophilum, three types of (bacterio)chlorophylls have previously been identified: bacteriochlorophyll a (BChl a), chlorophyll a (Chl a), and Zn-bacteriochlorophyll a′ (Zn-BChl a′) (Tsukatani et al. in J Biol Chem 287:5720–5732, 2012). Based upon experimental and quantum chemical 15N NMR data, we assign the observed signals to a Chl a cofactor. We exclude Zn-BChl because of its measured spectroscopic properties. We conclude that Chl a is the primary electron acceptor, which implies that the primary donor is most likely Zn-BChl a′. Chl a and 81-OH Chl a have been shown to be the primary electron acceptors in green sulfur bacteria and heliobacteria, respectively, and thus a Chl a molecule serves this role in all known homodimeric type-1 RCs. 相似文献
34.
In previous metrifonate (MTF) studies, there has been evidence for a preferential functional effect of the drug in cortical but not in striatal regions. In the present study we investigated the kinetics of brain cholinesterase (ChE) inhibition following an acute administration of MTF (100 mg/kg) in various brain regions of young and old Fischer 344 rats. The main objective was to test the hypothesis that the functional regional selectivity, observed in previous studies, was correlated with the extent of ChE inhibition. Using Karnovsky's method for histochemical staining, the highest staining intensity in control rats was found in the striatum and hippocampus, compared to a low basal activity in the frontal and frontoparietal cortices. In the striatum of drug treated old rats, enzyme inhibition was somewhat greater than that found in young rats. However, in the hippocampus, four to eight hours following MTF administration, the inhibition was greater in young compared to old rats. The differences in the sensitivity of various brain regions towards MTF induced ChE inhibition could not be correlated with the regional variation of MTF functional effects. 相似文献
35.
Photosynthetic inorganic carbon utilization and growth of Porphyra linearis (Rhodophyta) 总被引:2,自引:0,他引:2
Alvaro Israel Shlomit Katz Zvy Dubinsky John E. Merrill Michael Friedlander 《Journal of applied phycology》1999,11(5):447-453
Photosynthetic (oxygen evolution) and growth (biomass increase) responses to ambient pH and inorganic carbon (Ci) supply were
determined for Porphyralinearis grown in 0.5 L glass cylinders in the laboratory, or in 40 L fibreglass outdoor tanks with running seawater. While net photosynthetic
rates were uniform at pH 6.0–8.0, dropping only at pH 8.7, growth rates were significantly affected by pH levels other than
that of seawater (c. pH 8.3). In glass cylinders, weekly growth rates averaged 76% at external pH 8.0, 13% at pH 8.7 and 26%
at pH 7.0. Photosynthetic O2 evolution on a daily basis(i.e. total O2 evolved during day time less total O2 consumed during night time) was similar to the growth responses at all experimental pH levels, apparently due to high dark
respiration rates measured at acidic pH. Weekly growth rates averaged 53% in algae grown in fibreglass tanks aerated with
regular air (360 mg L-1 CO2) and 28% in algae grown in tanks aerated with CO2-enriched air (750 mg L-1 CO2). The pH of the seawater medium in which P. linear is was grown increased slightly during the day and only rarely reached 9.0. The pH at the boundary layer of algae submerged
in seawater increased in response to light reaching, about pH 8.9 within minutes, or remained unchanged for algae submerged
in a CO2-free artificial sea water medium. Photosynthesis of P. linearissaturated at Ci concentrations of seawater (K0.5560 μM at pH 8.2) and showed low photosynthetic affinity for CO2(K0.5 61 μM) at pH 6.0. It is therefore concluded that P. linearisuses primarily CO2 with HCO3
- being an alternative source of Ci for photosynthesis. Its fast growth could be related to the enzyme carbonic anhydrase whose
activity was detected intra- and extracellularly.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
36.
Transient induced gamma-band response in EEG as a manifestation of miniature saccades 总被引:1,自引:0,他引:1
The induced gamma-band EEG response (iGBR) recorded on the scalp is widely assumed to reflect synchronous neural oscillation associated with object representation, attention, memory, and consciousness. The most commonly reported EEG iGBR is a broadband transient increase in power at the gamma range approximately 200-300 ms following stimulus onset. A conspicuous feature of this iGBR is the trial-to-trial poststimulus latency variability, which has been insufficiently addressed. Here, we show, using single-trial analysis of concomitant EEG and eye tracking, that this iGBR is tightly time locked to the onset of involuntary miniature eye movements and reflects a saccadic "spike potential." The time course of the iGBR is related to an increase in the rate of saccades following a period of poststimulus saccadic inhibition. Thus, whereas neuronal gamma-band oscillations were shown conclusively with other methods, the broadband transient iGBR recorded by scalp EEG reflects properties of miniature saccade dynamics rather than neuronal oscillations. 相似文献
37.
This study examined p27 expression in a cohort of salivary malignancies (n = 74) for a prolonged period (20 years). Reduction of p27 expression was found to be a most powerful predictor for poor survival
and more so when the tumor concurrently expressed high levels of p53, TUNEL and heparanase markers, dramatically dropping
the patient survival probability to 0! While no patient whose tumor-staining profile included: p27 > 50%, p53 = 0, TUNEL = 0
and heparanase = 0, died of the disease during the 20-year follow up, the median of survival of the group with p27 ≤ 50%,
p53 > 0, TUNEL > 0 and heparanase > 0 was only 39 months. The survival probabilities of these two groups at 5 years were 100
and 50%, respectively, and at 20 years they were 100 and 0%, respectively (P = 0.05). Significant p27 reduction also resulted in significantly larger tumor size (T value), higher spread of neck metastasis and extra capsular spread and in more advanced disease (higher stage). Significant
correlation rates were found between age and poor survival, age and reduced p27 expression, and reduced p27 expression and
other general co-existing malignancies, indicating p27 reduction as part of a general phenomenon—age related mutagenesis.
Significantly more extensive therapy applied to patients with salivary reduced-p27 tumors could not prevent the rise in mortality
rate, questioning the justification for extensive therapy which is naturally accompanied by higher morbidity. Additional therapeutic
tools for fighting salivary cancer, possibly based on the new understanding of the p27, p53, TUNEL and heparanase carcinogenic
network, are necessary. 相似文献
38.
Isothermal microcalorimetry is a sensitive non-invasive analytical tool that can become useful in research on compost and other biosolids. The aim of the present study was to address several methodological aspects that are critical to the use of microcalorimetry to assess the dynamics of microbial activity in such systems. The results show that: (1) The calorimetric baseline is strongly influenced by the run temperature in the range relevant to composting systems (20–60 °C), and is also affected by addition of the water that is required to maintain or optimize microbial activity, presumably because some water evaporates through ampoule gaskets. (2) Amending mature compost with readily available substrates requires additional careful baseline treatment. (3) Sample heterogeneity can be successfully minimized by passing through a 2-mm sieve. Additional size separation can be useful to enable focusing on the more active fractions. (4) Oxygen depletion is a key feature in batch calorimetric analysis; for samples of highly active composts or manure, the total amount of heat released relative to the oxygen available in the ampoule may indicate the co-existence of anaerobic and aerobic metabolic pathways. Finally, practical recommendations for microcalorimetry analyses of pre-mature and mature composts are outlined. 相似文献
39.
Shlomit Goldman David H Lovett Eliezer Shalev 《Reproductive biology and endocrinology : RB&E》2009,7(1):41
Background
Although the MMP-2 promoter lacks a canonical progesterone response element (PRE), the hormone inhibits MMP-2 expression and is part of treatment protocols in gynecological invasive pathologies, including endometriosis and endometrial hyperplasia. This study aimed to explore the mechanism by which progesterone inhibits MMP-2 expression. 相似文献40.
Michal Amir Shabtai Romano Shlomit Goldman Eliezer Shalev 《Reproductive biology and endocrinology : RB&E》2009,7(1):152-8