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1

Plant heat shock transcription factors: divergence in structure and function

100%
Czarnecka-Verner E., Gurley W. B.
Biotechnologia
|
1999
|
issue 3
125-142
EN
A multitude of heat shock transcription factors (HSFs) have been isolated and characterized from various plant species (17-23). Based on a phylogeny analysis of the DNA binding domains and organization of oligomerization domains, they have been assigned to class A and B of the plant HSF family (20,24 and this paper). None of the tested soybean or Arabidopsis HSF class B members were able to function as transcriptional activators and are, therefore, considered to be inert (26,59). Conversely, class A HSFs from tomato and Arabidopsis displayed an intrinsic transcriptional activation potential (26,50). There seems to be variation among plant class A HSFs regarding their transcriptional activation functions: some play a key role in activation of the heat shock response, while others act in an auxiliary capacity as HSF activity boosters (54). In contrast, the class B inert HSFs are able to trans-attenuate the transcriptional activity of activator HSFs (26). We postulated that heat shock regulation in plants may differ from metazoans by partitioning negative and positive functional domains onto separate HSF proteins (59). In plants two classes of HSFs exist: class A members which function as activators of HSP gene expression, and a novel class B (inert HSFs) which is largely specialized for repression, or attenuation, of the heat shock response.
2
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CDP-choline (citicoline) attenuates brain damage in a rat model of birth asphyxia

88%
Fiedorowicz M., Makarewicz D., Stanczak-Mrozek K. I., Grieb P.
Acta Neurobiologiae Experimentalis
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2008
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vol. 68
|
issue 3
389-397
EN
To estimate protective potential of citicoline in a model of birth asphyxia, the drug was given to 7-day old rats subjected to permanent unilateral carotid artery occlusion and exposed for 65 min to a hypoxic gas mixture. Daily citicoline doses of 100 or 300 mg/kg, or vehicle, were injected intraperitoneally for 7 consecutive days beginning immediately after the end of the ischemic-hypoxic insult, and brain damage was assessed by gross morphology score and weight deficit two weeks after the insult. Caspase-3, alpha-fodrin, Bcl-2, and Hsp70 levels were assessed at 0, 1, and 24 h after the end of the hypoxic insult in another group of rat pups subjected to the same insult and given a single dose of 300 mg/kg of citicoline or the vehicle. Citicoline markedly reduced caspase-3 activation and Hsp70 expression 24 h after the insult, and dose-dependently attenuated brain damage. In the context of the well-known excellent safety profile of citicoline, these data suggest that clinical evaluation of the efficacy of the drug in human birth asphyxia may be warranted.
3

Arabidopsis class A and B HSFs show a spectrum of transcriptional activity

88%
Czarnecka-Verner E., Gurley W. B.
Biotechnologia
|
2002
|
issue 3
39-52
EN
A plethora of heat shock transcription factors (HSFs) has been obtained from various plant species (33,45-48,50,51). The Arabidopsis genome sequencing project provided confirmation of the existence of at least twenty one HSFs which were classified into three major classes, A, B and C, and numerous subclasses (9). Members of HSF class A displayed differential transcriptional activities in tobacco protoplasts that varied from 15- to 50-fold above the control level. This diversity of activity levels may reflect HSF variations regarding their transcriptional activation functions- some of the members might be the major heat inducible HSFs (class A1 HSFs), while others act in an auxiliary capacity as HSF activity boosters (38). Two new class B HSFs showed no transcriptional activation potential; however, they differed significantly in their ability to bind to heat shock elements (HSEs). The efficiency in HSE binding was linked directly with the ability to suppress the activity of endogenous tobacco HSFs. The suppression of endogenous HSFs by class B members provides further evidence that class B HSFs are not transcriptional activators, but are able to trans-attenuate the transcriptional activity of bona fide activator HSFs (34,41). The transcriptional competency of class C HSFs has not been determined.
4

Lactic acid bacteria cellular responses for enviromental stress

88%
Sadowska J., Grajek W.
Biotechnologia
|
2009
|
issue 4
115-132
EN
Lactic acid bacteria (LAB) constitute a heterogeneous group of bacteria that are traditionally used to produce fermented foods. The industrialization of food biotransformations increased the economical importance of LAB. The development of new applications such probiotic foods reinforces the need for robust LAB. They have to survive in the digestive tract, and express specific functions under conditions that are unfavorable to growth. A better understanding of the mechanisms of stress resistance and LAB cellular responses should allow to prepared these bacteria for industrial processes. Range of examples of diferent enviromental stress, related genes and molecular mechanisms of the stress responses are presented.
5

Germin genes expression induced by stress factors in transgenic tobacco plants (Nicotiana tabacum var. Xanthi)

63%
Nowakowska J.
Biotechnologia
|
2001
|
issue 2
152-164
EN
Wheat germin, a glycoprotein mainly localized in the cell wall of monocots, dicots and pine (Pinus caribaea Morelet), is a specific marker of the onset of growth in germinating seeds. There are two genes gf-2.8 and gf-3.8 of germin, isolated from wheat (Triticum aestivum). Because of their structure and biochemistry, both of the germin's isoforms have been now assimilated to the oxalate-oxidase enzyme (E.C. 1.2.3.4). Several constructs of the gf-2.8 and gf-3.8 genes promoters deletion were fused with uidA gene and tested for the GUS activity in the transgenic tobacco plants. The aim of this work was to evaluate whether some environmental factors induce the activity of germin. Hormonal treatment (auxins 2,4-D, NAA, gibberellin GA3), salt treatment, salicylic acid, heavy metals (Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg, As) and A1 induced high GUS activity in root apex, cotyledons and hypocotyls in transgenic seedlings and in leaves of the tobacco plants transformed with the entire and one partially deleted construct of the gf-2.8 gene. Neither cold nor heat shock, enhanced significant GUS activity. The gf-3.8 - GUS constructs of germin did not give a positive response to any factors mentioned above. Thus, only the gf-2.8 protein seems to be regulated by some factors. The gf-2.8 oxalate-oxidase activity could be then involved in general stress-induced signalling in higher plants
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