Raúl Cassia

Universidad Nacional de Mar del Plata | UNMDP · Biological Research Institute (IIB)

Photosynthetic organisms are continuously exposed to solar ultraviolet radiation-B (UV-B) because of their autotrophic lifestyle. UV-B provokes DNA damages, as cyclobutane pyrimidine dimers (CPD) or pyrimidine (6-4) pyrimidone photoproducts (6-4 PPs). The cryptochrome/photolyase family (CPF) comprises flavoproteins that are able to bind damaged or...

Ultraviolet-B (UV-B) radiation is a part of the sunlight, and plants sessile lifestyle involves continuous exposition to this radiation. Depending on its dose, UV-B could be both harmful, but also a photomorphogenic signal. In this chapter we summarize the knowledge about UV-B direct and indirect effects in plants, as well as the main responses of...

Low UV-B fluence is a signaling stimulus that regulates various physiological processes and induces photomorphogenic responses in plants. The specific UV-B receptor UVR8 is a key component in these processes. Although UVR8 sequence is conserved, few homologs have been cloned and reported to be functional. Here we show the cloning and functional ana...

The evidence presented here highlights the role of the nitric oxide (NO) as anti‐stress molecule, capable to handling with UV‐B‐induced changes in the redox state of cell. Our model proposes that the UV‐B perception triggers an increase in abscisic acid (ABA) concentration, which increases H2O2 and induces NO. In parallel, UV‐B activates the UV‐B r...

Low UV-B fluence is a signaling stimulus that regulates various physiological processes and induces photomorphogenic responses in plants. The specific UV-B receptor UVR8 is a key component in these processes. Although UVR8 sequence is conserved, few homologs have been cloned and reported to be functional. Here we show the cloning and functional ana...

Here, we review information on how plants face redox imbalance caused by climate change, and focus on the role of nitric oxide (NO) in this response. Life on Earth is possible thanks to greenhouse effect. Without it, temperature on Earth’s surface would be around -19°C, instead of the current average of 14°C. Greenhouse effect is produced by greenh...

Ultraviolet-B (UV-B) is present in sunlight (280–315 nm) and has diverse effects on living organisms. Low fluence rate of exposure induces a specific photomorphogenic response regulated by the UV-B response locus 8 (UVR8) receptor. UVR8 was first described in Arabidopsis thaliana. In the absence of stimuli it is located in the cytoplasm as a homodi...

MYB proteins are a family of transcription factors that play an important role in plant development and regulatory defense processes. Arabidopsis thaliana MYB30 (AtMYB30), a member of this protein family, is involved in cell death processes during the hypersensitive response (HR) of plants. HR is characterized by a vast production of reactive oxyge...

Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) is a UV-B photoreceptor that mediates UV-B photomorphogenic responses. UVR8 signaling involves CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), the ELONGATED HYPOCOTYL5 (HY5) transcription factor and the closely related HY5 HOMOLOG (HYH). Some UV-B responses mediated by UVR8 are also regulated by nitric oxid...

Brassinosteroids (BRs) regulate various physiological processes, such as tolerance to stresses and root growth. Recently, a connection was reported between BRs and nitric oxide (NO) in plant responses to abiotic stress. Here we present evidence supporting NO functions in BR signaling during root growth process. Arabidopsis seedlings treated with BR...

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Cristina Lombardo, Lorenzo Lamattina, Raul Cassia. Several figures in the article by Tossi et al appear to have been intentionally manipulated...

Abscisic acid (ABA) signaling pathways have been widely characterized in plants, whereas the function of ABA in animals is less well understood. However, recent advances show ABA production by a wide range of lower animals and higher mammals. This enables a new evaluation of ABA signaling pathways in different organisms in response to common enviro...

UV-B is an abiotic environmental stress in both plants and animals. Abscisic acid (ABA) is a phytohormone regulating fundamental physiological functions in plants, including response to abiotic stress. We previously demonstrated that ABA is an endogenous stress hormone also in animal cells. Here, we investigated whether autocrine ABA regulates the...

The link between ultraviolet (UV)-B, nitric oxide (NO) and phenylpropanoid biosynthetic pathway (PPBP) was studied in maize and Arabidopsis. The transcription factor (TF) ZmP regulates PPBP in maize. A genetic approach using P-rr (ZmP+) and P-ww (ZmP⁻) maize lines demonstrate that: (1) NO protects P-rr leaves but not P-ww from UV-B-induced reactive...

Nitric oxide (NO) is a small, ubiquitous bioactive molecule, postulated as a broad spectrum anti-stress compound. The NADPH oxidase inhibitor apocynin induces the accumulation of endogenous NO in leaves of maize seedlings through a nitric oxide synthase (NOS)-like activity, and confers an augmented tolerance to UV-B-induced oxidative damage. Here w...

The effect of apocynin on nitric oxide (NO) synthesis and oxidative stress was studied in corn (Zea mays) seedlings. After treatment with 100 microM apocynin, strongly increased amounts of NO were detected in the leaves. This NO production was reduced by more than 70% by N(G)-nitro-l-arginine methyl ester (L-NAME), a NO synthase (NOS) inhibitor, bu...

Here, the link between UV-B stimulus and the abscisic acid (ABA)-induced nitricoxide (NO) synthesis pathway was studied in leaves of maize (Zea mays).The ABA concentration increased by 100% in UV-B irradiated leaves. Leaves of viviparous 14 (vp14), a mutant defective in ABA synthesis, were more sensitive to UV-B-induced damage than those of the wil...

Nitric oxide (NO) can influence the transcriptional activity of a wide set of Arabidopsis genes. The aim of the present work was to investigate if NO modifies DNA-binding activity of AtMYB2 (a typical R2R3-MYB from Arabidopsis thaliana), by a posttranslational modification of its conserved Cys53 residue. We cloned a fully active minimal DNA-binding...

The epidermal growth factor receptor (EGFR) is abnormally activated in cancer and two classes of anti-EGFR agents, monoclonal antibodies and low-molecular-weight tyrosine kinase inhibitors, have shown antitumor activity in patients. Because these two classes of antireceptor agents target the EGFR at different sites, we decided to explore whether th...

Cyclin E overexpression occurs in a subset of endometrial carcinomas (ECs), but the molecular mechanisms underlying this alteration remain to be established. The present study has analysed amplification of the cyclin E gene (CCNE) and mutation in hCDC4, the gene coding for the F-box protein, which tags phosphorylated cyclin E for proteosomal degrad...

Endometrial carcinoma (EC) comprises at least two types of cancer: endometrioid carcinomas (EECs) are estrogen-related tumors, which are frequently euploid and have a good prognosis. Nonendometrioid carcinomas (NEECs; serous and clear cell forms) are not estrogen related, are frequently aneuploid, and are clinically aggressive. We used cDNA microar...

Abnormal expression of cadherins and catenins plays a critical role in the initiation and progression of multiple human tumours. This study aimed to evaluate the immunoreactivity of E- and P-cadherin, beta- and gamma-catenin, and p120ctn in premalignant and malignant endometrial lesions and to correlate their membranous expression with clinicopatho...

The activation of the APC/beta-catenin signalling pathway due to beta-catenin mutations has been implicated in the development of a subset of endometrial carcinomas (ECs). However, up to 25% of ECs have beta-catenin nuclear accumulation without evidence of beta-catenin mutations, suggesting alterations of other molecules that can modulate the Wnt p...

This work shows that the infection of potato (Solanum tuberosum) detached leaves by the late blight pathogen Phytophthora infestans, was drastically reduced by adding deferoxamine, an exogenous iron chelator. Reactive oxygen species in leaves inoculated with P. infestans were also reduced after adding deferoxamine. A leaf ferritin cDNA fragment was...

Fish protein hydrolysates (FPHs) were obtained from four different fish species using an autolytic process. Their characteristics and properties were studied. FPHs have high protein and low lipid contents. Their amino acid compositions are similar to FAO/WHO standards, with a low content of hydrophobic amino acids. These features and the molecular...

Transferrin (Tf), the iron transport protein, is essential for the growth and differentiation of cells. Therefore, it provides an excellent model to analyze the regulatory mechanisms controlling the expression of a eukaryotic gene in different cell types and during fetal and adult life. In this study, the tissue-specific and developmental regulatio...

The orphan ligand nuclear receptor Rev-erbbeta acts in vitro as a negative regulator of transcription. However, its precise physiological role is still unknown. As a first attempt to better understand its biological function, we have studied the distribution and the localization of the Rev-erbbeta mRNA transcripts in different mouse embryonal carci...

Transferrin (Tf), the iron transport protein, is essential for the growth and differentiation of cells. Therefore, it provides an excellent model to analyze the regulatory mechanisms controlling the expression of a eukaryotic gene in different cell types and during fetal and adult life. In this study, the tissue-specific and developmental regulatio...

Rev-erb beta is a member of the nuclear receptor superfamily, which includes a group of transcription factors involved in the response to steroids, vitamin D, retinoic acids, and other lipophilic molecules. The Rev-erb nuclear receptors exist at least in two forms, namely alpha and beta, with a high degree of evolutionary conservation at the level...

Plants respond to pathogen infection and environmental stress by regulating the coordinate expression of many stress-related genes. In plants, the expression of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is induced under environmental stress. This work was aimed at investigating whither the expression pattern of cytosoli...

We have isolated a rat complementary DNA clone corresponding to a novel isoform of the hormone nuclear receptor superfamily. This clone encodes a 383 amino acid residue protein designated as Rev-erb beta 2. This protein is identical until residue 382 to the Rev-erb beta 1 protein, which is 195 amino acids longer. Several arguments pointed out that...

The proteolytic activity in isolated liver nuclei from mice subjected to different conditions of protein nutrition and its relationship with histones metabolism was studied. After five days of protein depletion, the nuclear azocaseinolytic activity increases concomitantly with a decrease in the concentration of histones. This activity resembles, in...

The effect of protein depletion and refeeding on the metabolism of mouse liver nuclear proteins was studied. Five days protein depletion caused a 35% decrease in total nuclear protein. A fast recovery of the lost proteins, except histones, was induced when depleted mice were refed with a normal diet. Depletion caused a decrease in total nuclear pro...

Proteolytic activities at pH 5.0 and pH 7.4 in both kidney and liver during refeeding of protein-depleted mice were determined. Under this nutritional condition, the in vivo rate of protein breakdown is inhibited. Protein depletion caused in both kidney and liver a loss of pH 5.0 proteolytic activity. It was restored to normal values after 12 hours...