Abc of the ABC Transporters in Human Organism

Summary: The ABC transporters are, after all,  pumps responsible for elimination of xenobiotics (also chemotherapeutic agents)  from the cell. Because of this reason the inhibitors of such transporters have been claimed to be important in the therapy. But it has turned out, that the ABC transporters are responsible not only for MDR (MultiDrug Resistance) phenomenon, but also for lipid transport (ABCA and ABCG except for ABCG2), regulation of intracellular processes like protein translation (ABCE and ABCF), peroxisome activity (ABCD), insulin secretion (ABCC8 and ABCC9) and regulation of mucus hydration in bronchi. Some diseases are caused by the defects of the ABC transporters, for instance cystic fibrosis (result of ABCC7 – CFTR mutation). In the current researches, new aspects of ABC transporters are being discovered. This article aims to present general aspects of ABC transporters like structure and evolution, as well as to go through the main function of the transporters.

Key words:
[Postępy Biologii Komórki 2012; 39: 143–158]

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Łukasz SICZEK, Agnieszka MOSTOWSKA

Characteristics and Function of ,,Plant Caspases” during Programmed Cell Death in Plants

Summary: Plant caspases and their function during programmed cell death in plants were presented in this article. Programmed Cell Death is a process during which cells die in a strictly controlled manner. Caspases are cysteine proteases which execute apoptosis in animal cells. They hydrolyze peptide bonds after aspartic acid residues. Plants possess some groups of enzymes which resemble caspases: vacuolar processing enzymes, saspases, phytaspases, metacaspases, but do not fulfill basic criterions that allow considering them as caspases. Vacuolar processing enzymes (VPE) belong to cysteine proteases and possess caspase activity. Saspases and phytaspases, although having serine in the active center, possess also caspase activity. Metacaspases do not have caspase activity. VPE are localized in the vacuole and are responsible for breaking tonoplanst. Saspases and phytaspases act both inside and outside of the cell. Saspases activate a cascade of proteolytic enzymes, whereas phytaspases can directly degrade proteins in the cell. Metacaspases directly degrade important cell components, probably in the cytosol. Plant caspases, in spite of superficial similarities to animal caspases, are only their functional equivalents, therefore we use quotation mark. They degrade important for cell structures or proteins, leading to cell death.

Key words:  programmed cell death, “plant caspases”, vacuolar processing enzymes, metacaspases, saspases, phytaspases

[Postępy Biologii Komórki 2012; 39: 159–172]

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Cancer Diagnostics and Treatment in Molecular and Immunohistochemical View – Where Are We?

Summary: The last few decades is the time of huge progress in area of cancer treatment and diagnostics. Cytogenetics, molecular and immunohistochemical techniques are the most common and helpful tools used in cancer diagnostics, as well as in cancer therapy. This article is the review of the latest researches in the field of cancer protection and treatment.

Key words: 
cancer, diagnostics, prognosis, therapy

[Postępy Biologii Komórki 2012; 39: 173–188]

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Kazimierz KOCHMAN

Key Role of Omega-3 and Omega-6 Fatty Acids in Human Biology; Crawford’s Predictive Theory of Evolution

Summary: For proper and healthy functioning of human organism it is important to consume a diet containing essential fatty acids omega-3 and omega-6 (EFA) that means linoleic acid (LA) and ?-linolenic acid (LNA) or directly arachidonic acid (ARA) and docosahexaenoic acid (DHA) in the right proportions. Based on the accumulated results of numerous studies, Crawford defined a new theory of evolution, which proposes that the driving force in evolution is the presence and availability of appropriate nutrients in the environment. According to this theory, omega-3 and omega-6 especially DHA helped to form the human brain with all its complexity and uniqueness, which is unique in the living world. If all data on the role of omega-3 and omega-6 fatty acids, shown in numerous scientific publications and in population studies, were true we can formulate the conclusion that the health of the next generations is very dependent on the assurance of proper nutrition of future mothers during pregnancy, and that omega-3 and omega-6 in balanced proportions, can play the key role in this process. Therefore, the profound investigations of this problem and also introduction of balanced nutrition of omega-3 and omega-6, will be essential to maintain the good health of future generations.

Key words:  brain, evolution, nutrition, essential fatty acids (EFA), omega-3, omega-6, Crawford

[Postępy Biologii Komórki 2012; 39: 189–198]

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Quercetin in Anticancer Therapy

Summary: Quercetin belongs to the flavonoids, commonly present in fruits and vegetables. Its daily intake vary between 25 and 35 mg. Human diet rich in quercetin decreases the risk of heart attack, atherosclerosis and varices. It possesses anti-inflammatory, anti-allergic and anticancer properties. It is strong antioxidant. Quercetin blocks cell cycle and induces apoptosis by modifying the expression of signaling proteins, receptors and transmission through intracellular pathways. It protects normal cells. Unfortunately, some information about neurotoxic and mutagenic effect of quercetin appeared. Thus, in the article, the positive as well as negative properties of the flavonoid were discussed.

Key words: quercetin, bioavailability, cancers, apoptosis, cell cycle, chemotherapy

[Postępy Biologii Komórki 2012; 39: 199–216]

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Mechanisms of Lead Toxicity

Summary: Lead is the most common naturally occurring heavy metal and one of the few that are found in a pure form. Because of its chemical properties it has already been used by the oldest civilizations, early people experienced its toxic properties. In this paper, we present the influence of lead on the human body and its interaction with macromolecules (proteins and nucleic acids) and cellular structures. We discuss as well the mechanism of its toxicity at the molecular level.

Key words:
  lead, Pb-protein complexes, RNA hydrolysis, leadzyme
[Postępy Biologii Komórki 2012; 39: 217–2484]

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Chromatin Remodeling as a General Molecular Mechanism of Glucocorticoid Receptor Action

Summary: Specific tissue response to endogenic and synthetic glucocorticoids (GCs) is controlled at different levels of cell function: target gene transcriptions, glucocorticoid receptor (GR) protein translation, GR activation and translocation to the nucleus. Molecular mechanism of GR action is related to genomic regulation of gene expression, i.e., transactivation or transrepression of steroid-sensitive genes via interaction with gene promoter, influence on mRNA stability of some proteins, interaction with numerous transcription factors, microRNAs as well as influence on chromatin remodeling. Non-genomic mechanism of GR action is connected with activation of secondary transmitters and signaling pathways via nuclear and membrane receptors associated with ion channels as well as through interaction with tyrosine and serine/threonine kinases and adaptor proteins. Molecular  mechanism of GK activity may determine the proper or lack of response on GK in the treatment of many autoimmune and inflammatory diseases including asthma, multiple sclerosis, Crohn diseases or POChP.

Keywords: glucocorticoid receptor, chromatin remodeling, inflammation, transcription factors, MAPK signaling pathway

[Postępy Biologii Komórki 2012; 39:  249–268]

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Agnieszka TOMA, Wiesława WIDŁAK, Natalia VYDRA

The Role of Heat Shock Transcription Factor 1 in Carcinogenesis

Summary: Heat Shock Factor 1 (HSF1) is a transcription factor activated during environmental stress, which leads to HSPs (Heat Shock Proteins) expression. HSPs serve as molecular chaperons in the refolding of proteins, and in enhancing cellular resistance to apoptosis, therefore having important cytoprotective functions. In many tumor types, HSF1 and HSPs are overproduced. HSF1 can support the neoplastic transformation as well as enhance survival of tumor cells in their microenvironment, by modulating many signal transduction pathways that control cell growth, proliferation, apoptosis, metabolism and cell motility. HSF1 can cause genomic instability by overriding cell cycle checkpoints. Heat Shock Elements (HSEs), recognized by HSF1, are present not only in HSP promoters but also in ABCB1 (MDR1) gene, coding for P-glycoprotein, which actively removes drugs from the cell. In accordance with this observation, HSF1 would provide a selective advantage to tumor cells during cancer therapy. The normal cytoprotective role of HSF1 is highly undesirable in cancer, and validates it as a new, important therapeutic target.

Key words: Heat Shock Factor 1, Heat Shock Proteins, carcinogenesis
[Postępy Biologii Komórki 20121; 39: 269–288]

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Multifunctional Germin Protein and Germin-Like Proteins in Plants

Summary: Germins and germin-like proteins constitute a large and very diverse family of ubiquitous plant proteins. They belong to the cupin superfamily of proteins which name comes from the domain of b-barrel structure (from the Latin Cupa - small barrel). It is evolutionary conserved domain localized in C- terminal end. It consists of two amino acid sequence motifs: 1 and 2, described as the ‘germin box’. Cupin domain determines the high thermal stability, which is come out of the presence of disulphide bridges and the glycosylation degree. The presence of domain cupin suitable these proteins resistance to the protease protein. Germins occur in two isoforms gf-2.8 and gf-3.8 encoded by the gf-2.8 and gf-3.8 genes, active during the embryos germination of all economically important crops. In both  genes there are regions without introns, which encode 224 amino acids, showing 90% homology. It is interesting that in the 5’ region of gf-2.8 gene; there are two sequence motifs characteristic of auxin genes. There has been distinguished six subfamilies of germin-like proteins with different enzymatic activity. There has been recognized a lot of germin-like proteins involved in plant defense responses against pathogens and pests. Defensive activity of GLP was found in apoplast which are expressed and react with the cell wall by facilitating an early response to pathogen attack. Particularly important are GLPs with oxalate oxidase activity, because they lower levels of oxalate, which is a virulence factor produced by several fungal pathogens. Transcription of the genes encoding germins and oxalate oxidase activity is stimulated by fungal infections and some metal ions. Wheat germin also have enormous potential for commercial applications because of the previously mentioned unusual resistance to proteases, high stability and resistance to heat.

Key words:  cupins, germins, GLPs

[Postępy Biologii Komórki 20121; 39: 289–300]

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Agnieszka GRAFKA, Maciej ŁOPUCKI

The Application of Stem Cells in Medicine

Summary: The number of carried out scientific studies concerning various applications of stem cells in medicine has increased in recent years. In the literature numerous new reports present developments in applications of stem cells not only in hematology but also in treatment of inter alia chronic and genetic diseases, diabetes, neurological disorders, skin burns, spinal cord after mechanical injury or regeneration of damaged heart muscle and many others. The widespread application of stem cells in medicine raises ethical controversies. In this paper we review the literature concerning positive and negative aspects of stem cells applications in research aimed particularly at obtaining blood cells.

Key words: regenerative medicine, hematopoietic stem cells, umbilical cord blood stem cells
[Postępy Biologii Komórki 20121; 39: 301–315]

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