bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Study of Cytochrome cM Formation in Synechocystis
Authors: Shuvalov Vladimir A. , Allakhverdiev Suleyman I. , Sakamoto Atsushi , Malakhov Michael , Murata Norio 
Published: September 2003

AbstractThe expression of the cytM gene, which encodes cytochrome cM in Synechocystis sp. PCC 6803, is induced under stress conditions such as low temperature. Results of spectrophotometric studies revealed that cytochrome cM was oxidized by light absorbed by photosystem I in cells that had acclimatized to a low temperature. However, no similar light‐induced oxidation of cytochrome cM
Contribution of the Residue Glu9, Glu46, and Phe49 to the Biological Activity of Insulin‐Like Growth Factor‐1
Authors: Chen Hui , Feng You‐Min 
Published: September 2003

AbstractThree recombinant single‐chain insulin mutants, [B10Glu]Ins/IGF‐1(C), [A5Glu]PIP, and [A8Tyr]PIP were prepared by means of protein engineering. In the three mutants, the residue at position 10 of insulin B chain and positions 5 and 8 of insulin A chain were substituted by the corresponding residue Glu9, Glu46, and an aromatic residue at 49 of IGF‐1, respectively. The growth‐promoting activity of [B18Glu]Ins/IGF‐1(C) is 58‐fold higher than insulin and of [A5Glu]PIP, and [A8Tyr]PIP is 2.5‐ and 4.7‐fold higher than PIP, respectively, measured using a mouse mammary tumor cell line GR2H6 in vitro. The results show that the residues Glu9, Glu46, and Phe49, especially the Glu9, play an important role in the growth‐promoting function of IGF‐1. Based on the results, we suggest that the insulin could be used as a scaffold to investigate the contributions of residues of IGF‐1 to its biological function.
Molecular Basis of the Anaerobic Response in Plants
Authors: Dolferus Rudy , Klok Erik Jan , Ismond Kathleen , Delessert Christian , Wilson Sarah , Good Allen , Peacock Jim , Dennis Liz 
Published: September 2003

AbstractThe response of plants to flooding is complex and involves the induction of specific gene sets. A multidisciplinary approach by several research teams has led to a reasonably good understanding of the low oxygen response, and many of the genes and proteins that are involved are known. But the factors that are critical in determining tolerance or intolerance remain unknown. Microarray technology offers renewed hope to unravel the complex changes in gene expression occurring in plants upon low oxygen treatment and what mechanisms are involved in the response.
Protein Tyrosine Phosphatases: Dephosphorylating the Epidermal Growth Factor Receptor
Authors: Tiganis Tony 
Published: September 2003

AbstractProtein tyrosine phosphatases (PTPs) are a large and structurally diverse family of enzymes that are found in eukaryotes, prokaryotes, viruses, and plants. PTPs catalyse the dephosphorylation of tyrosyl phosphorylated proteins and can either antagonise or potentiate protein tyrosine kinase signalling. PTPs regulate fundamental cellular processes and have been implicated in the etiology and pathogenesis of various human diseases. The epidermal growth factor receptor (EGFR) is a widely distributed protein tyrosine kinase that regulates both normal development and plays a role in pathological conditions such as cancer. This review discusses the structure and function of PTPs and focuses on the PTPs that have been implicated in the dephosphorylation of the EGFR and the consequent suppression of EGFR signalling.
The Myotubularin Family: Novel Phosphoinositide Regulators
Authors: Nandurkar Harshal H. , Huysmans Richard 
Published: September 2003

AbstractPhosphatidylinositol 3‐phosphate [PtdIns(3)P] acts as a second messenger via the recruitment of diverse signalling proteins to various cellular compartments. Recent advances have highlighted the association of human diseases with mutations in phosphatases that regulate PtdIns(3)P levels. Myotubularin, the gene mutated in myotubular myopathy, functions as a lipid phosphatase with specificity for PtdIns(3)P. It is now apparent that there is an increasing family of proteins that are defined by their significant homology with myotubularin. The myotubularin‐related gene family includes proteins that exhibit a lipid phosphatase catalytic motif, those that contain mutations of the critical catalytic residues, and at least one protein that functions as an adapter subunit for PtdIns(3)P‐3‐phosphatase activity. The present challenge is to understand how deregulation of phosphoinositide metabolism causes human disease.
From Cytosol to Organelles: 14‐3‐3 Proteins as Multifunctional Regulators of Plant Cell
Authors: Aducci Patrizia , Camoni Lorenzo , Marra Mauro , Visconti Sabina 
Published: September 2003

Abstract14‐3‐3 proteins are a class of highly conserved proteins widespread in eukaryotes. They regulate several cellular processes through phosphorylation‐dependent interaction with their targets. Since their discovery in plants, a number of peculiar functions have been ascertained, such as regulation of primary metabolism, ion transport, cellular trafficking, chloroplast and mitochondrial enzyme activities and gene transcription. The still increasing body of evidence suggests that 14‐3‐3s may function as versatile proteins able to move from cytosol to different cellular organelles. This review will focus on the broad range of regulatory tasks carried out by 14‐3‐3s in the different compartments.
Inositol Polyphosphate 5‐Phosphatases: Lipid Phosphatases With Flair
Authors: Mitchell Christina A. , Gurung Rajendra , Kong Anne M. , Dyson Jennifer M. , Tan April , Ooms Lisa M. 
Published: September 2003

AbstractRecent studies have identified the inositol polyphosphate 5‐phosphatases as a large family of signal modifying enzymes comprising 10 mammalian and 4 yeast family members. A number of investigations including gene‐targeted deletion of 5‐phosphatases in mice have demonstrated that these enzymes regulate many important cellular events including hematopoietic cell proliferation and activation, insulin signaling, endocytosis, and actin polymerization.
Genomic Structure and Promoter Analysis of the Bovine Leptin Gene
Authors: Taniguchi Yukio , Itoh Tomohiro , Yamada Takahisa , Sasaki Yoshiyuki 
Published: September 2003

AbstractThe product of the leptin gene is a 16‐kDa protein secreted by adipose tissue and regulates adiposity. The leptin gene could be a potential candidate gene controlling some proportion of adipose and lean accretion in cattle, and thus, may be referred to as one of genetic factor controlling meat quality determinants such as marbling. We have isolated the bovine leptin gene including its promoter region. We have determined the exon‐intron organization of the bovine leptin gene, which consisted of three exons and two introns and spanned about 18.9 kb, equivalent to that of human or mouse gene. A ∼3‐kb 5'‐flanking region upstream from the putative transcription start site of the gene contained consensus Sp1 and CCAAT/enhancer‐binding protein (C/EBP) motifs, and transient transfection assay with secreted alkaline phosphatase reporter confirmed the promoter activity in 3T3‐L1 cells that possessed expression of the cotransfected C/EBP αexpression plasmid. Cotransfection with C/EBP αcaused 24‐fold activation in leptin reporter expression, as compared to cotransfection with control plasmid, consistent with existence of the putative C/EBP αbinding site in the proximal 5'‐flanking region of the bovine leptin gene.
Animals are Dependent on Preformed α‐Amino Nitrogen as an Essential Nutrient
Authors: Katagiri Masayuki , Nakamura Masahiko 
Published: September 2003

AbstractIt has traditionally been thought that animals can utilize ammonia for amino acid biosynthesis, and that for them some amino acids are nutritionally nonessential. Presumably this idea originates from the notions of Schoenheimer (G. L. Foster et al. [1939] J. Biol. Chem. 127, 319‐327) and of Rose (W. C. Rose et al. [1948] J. Biol. Chem. 176, 753‐762), which we question for the following reasons. First, Schoenheimer's experiments only showed the incorporation of ammonia into amino acids. This may occur simply as an exchange between ammonia and the α‐amino group of endogenous amino acids and reflects the enzymatic properties of glutamate dehydrogenase, which is a reversible enzyme. Second, Rose's nutritional experiments were concerned with whether carbon skeletons of particular amino acids can (nonessential) or cannot (essential) be synthesized from common intermediates of carbohydrate metabolism. We propose that mammals, living as they do at the top of the food web, are absolutely dependent directly or indirectly on higher plants and microorganisms for preformed α‐amino nitrogen per se and that the first joining of C ‐ and N ‐atoms to make glutamate constitutes a basic anabolic system in nature after the fixation of CO 2 and N 2 .
tRNALys3: The Primer tRNA for Reverse Transcription in HIV‐1
Authors: Kleiman Lawrence 
Published: September 2003

AbstractDuring the assembly of HIV‐1, tRNA Lys isoacceptors are selectively packaged into the virion, and one of these, tRNA Lys3, is annealed to the viral RNA genome where it acts to prime the reverse transcriptase (RT)‐catalyzed synthesis of viral DNA. We review herein what is known about the selective packaging and annealing of primer tRNA Lys3 . Current evidence suggests that a complex of two major precursor viral proteins, Pr55 gag and Pr160 gag‐pol, interact with a tRNA Lys /lysyl‐tRNA synthetase (LysRS) complex during viral assembly, with Pr55 gag interacting with both LysRS and Pr160 gag‐pol, and RT sequences within Pr160 gag‐pol binding to tRNA Lys . LysRS appears to target the tRNA Lys isoacceptors for incorporation into HIV‐1. In the virion, the 3' terminal 18 nucleotides of tRNA Lys3 anneals to an 18‐nucleotide sequence at the 5' terminal region of viral RNA termed the primer binding site (PBS). Evidence is presented that other regions on the tRNA Lys3 also anneal with other regions in viral RNA upstream of the PBS, resulting in a destabilized tRNA Lys3 structure. Both viral and tRNA Lys3 regions need to be denatured to establish annealing, and the roles of both viral and cellular proteins in this process are discussed.
Nitric Oxide Limits Parasite Development in Vectors and in Invertebrate Intermediate Hosts
Authors: Gradoni Luigi , Ascenzi Paolo 
Published: September 2003

AbstractNitric oxide (NO) possesses antiparasitic effects on both Protozoa and Metazoa in vertebrate definitive and intermediate hosts. Inducible NO limits parasite development also in Rhodnius prolixus and Anopheles stephensi, the natural vectors of human trypanosomiasis and malaria respectively, and in the snail Biomphalaria glabrata, a natural invertebrate intermediate host of human schistosomiasis. Therefore, NO limits Trypanosoma, Plasmodium, and Schistosoma development at all stages of the parasite life cycle.
BAG‐1, An Anti‐Apoptotic Tumour Marker
Authors: Tang Shou‐Ching 
Published: September 2003

AbstractBAG‐1 is a multifunctional and anti‐apoptotic or anti‐cell death protein that interacts with a variety of cellular proteins and affects their functions. On the cell surface, it binds to the cytosolic domain of the growth factor receptors and enhances the protection from cell death triggered by growth factor receptors. In the cytosol, it binds to Bcl‐2 and heat shock protein, and modulates their functions. In the nucleus, it binds to a variety of nuclear hormone receptors and inhibits hormone‐induced apoptosis. BAG‐1 is widely overexpressed in a variety of tumour cell lines and cancer tissues. In addition, differential expression of BAG‐1 isoforms has been observed. Preclinical studies indicate that overexpression of BAG‐1, especially its nuclear and cytoplasmic isoforms, may be useful as a prognostic and/or predictive biomarker. Pilot clinical studies have demonstrated that overexpression of nuclear BAG‐1 may be associated with a shorter survival in breast and laryngeal carcinomas. Conversely, overexpression of cytoplasmic BAG‐1 may be associated with a better clinical outcome in early stage breast cancer and in non‐small cell lung cancer. Further large‐scale clinical studies are warranted to establish the role of BAG‐1 as a novel prognostic and/or predictive biomarker in the clinical management of these common malignancies.
Oxalate, Germins, and Higher‐Plant Pathogens
Authors: Lane Byron G. 
Published: September 2003

AbstractEarlier surveys ( 1, B. G. Lane. [1991] FASEB J. 5, 2983‐2901; 2, B. G. Lane. [1994] FASEB J. 8, 294‐301) helped to uproot entrenched views of plant oxalate as a static substance. It is now recognized that oxalate oxidases (OXOs) found in the “true cereals” (barley, maize, oat, rice, rye, wheat), the so‐called germin OXOs (G‐OXOs), or simply germins, are involved in cereal defence responses to invasion by fungal pathogens and that they show promise of being valuable agents of plant defence in dicotyledons, where they are not found naturally. G‐OXOs have very peculiar properties: (a) their water‐soluble oligomeric structures and enzymic activity are stable during SDS‐PAGE and nitrocellulose blotting, (b) their undenatured water‐soluble forms are refractory to the action of broad‐specificity proteases, (c) their water‐insoluble forms occur abundantly (∼50%) in the extracellular matrix (cell walls) of wheat, and probably in varying amounts in the cell walls of other true cereals. Transfer of the wheat G‐OXO coding element to dicotyledons has been found, in all cases so far examined, to result in improved resistance to fungal pathogens. The possible nature of the improved resistance is discussed in relation to (a) generation of microcidal concentrations of hydrogen peroxide when the G‐OXOs act on oxalate, (b) elicitation of hypersensitive cell death at lower concentrations of hydrogen peroxide, (c) formation of effective barriers against predator penetration by the hydrogen‐peroxide‐mediated lignification of cell walls, and (d) destruction of oxalate, which is an inhibitor of the hypersensitive response, a strategy of particular importance in the case of ubiquitous predator organisms such as Sclerotinia sclerotiorum, which secrete high concentrations of oxalate as a toxin.
Atrial Natriuretic Peptide Prohormone Gene Expression: Hormones and Diseases That Upregulate its Expression
Authors: Vesely David L. 
Published: September 2003

AbstractAtrial natriuretic peptides consist of a family of peptide hormones that are synthesized by three separate genes and then stored as three different prohormones (i.e., 126‐amino acid [a.a.]) atrial natriuretic peptide (ANP), 108‐a.a. brain natriuretic peptide (BNP), and 126‐a.a. C‐natriuretic peptide (CNP) prohormones. The gene encoding for the synthesis of the atrial natriuretic peptide prohormone (proANP) consists of three exons and two introns. Exon 1 encodes the signal peptide and the first 16 a.a. of the ANP prohormone. These 16 a.a. form the N ‐terminus of a peptide hormone named long‐acting natriuretic hormone (LANH). A valine‐to‐methionine substitution in LANH results in a 2‐fold increased incidence of strokes in humans. Exon 2 of the proANP gene encodes for three peptide hormones, i.e., vessel dilator, kaliuretic hormone, and ANP. Each of the proANP gene products have vasodilatory, diuretic, natriuretic, and/or kaliuretic properties. Stretch, glucocorticoids, thyroid hormone(s), mineralocorticoids, and calcium enhance proANP gene expression. Enhanced proANP gene expression is found in congestive heart failure, hypertension, and cirrhosis with ascites. The proANP gene is present with invertebrates and plants as well as in humans and other vertebrates.
Prediction of Drug Resistance in M. tuberculosis: Molecular Mechanisms, Tools, and Applications
Authors: Victor Thomas C. , van Helden Paul D. , Warren Robin 
Published: September 2003

AbstractManagement of Tuberculosis is complicated by the emergence of drug resistant strains of Mycobacterium tuberculosis and this poses a threat to the success of Tuberculosis control programmes. Drug susceptibility testing by culture is time‐consuming and technically difficult. It is known that resistance to drugs is due to a number of genomic mutations in specific genes of M. tuberculosis . These mutations in combination with molecular techniques can be used as markers for drug resistance, since drug susceptible isolates lack the corresponding gene mutations. This review focuses on molecular mechanisms, methods and applications as a possible new diagnostic tool for the early molecular detection of drug resistance in M. tuberculosis .
Oesophageal Cancer in Africa
Authors: Hendricks Denver , Parker M. Iqbal 
Published: September 2003

AbstractOesophageal cancer, the eighth most frequent cancer in the world occurs as two main subtypes, squamous cell carcinoma (more prevalent in developing countries) and adenocarcinoma (more common in developed countries). Certain populations of central, eastern, and southern Africa display very high frequencies of oesophageal squamous cell carcinoma, presenting a serious health burden to the continent. Most patients are diagnosed at a late stage because of the asymptomatic development of the disease, with associated poor prognosis. A better understanding of the aetiological agents and molecular mechanisms involved in the development of oesophageal squamous cell carcinoma may offer opportunities to reduce exposure to environmental risk factors and also allow early diagnosis or predict response to therapy. Epidemiologic studies have identified smoking, alcohol consumption, diets poor in fresh fruit and vegetables, consumption of foods contaminated with Fusarium verticillioides, and HPV infection as risk factors associated with the development of this disease in Africa. Although we have an incomplete understanding of the molecular events involved in the development of oesophageal squamous cell carcinoma, advances have been made that suggest lines of future exploration. South African patients with oesophageal squamous cell carcinoma display a lower incidence of point mutations in the p53 gene than described elsewhere, suggesting that the profile of aetiological agents may be different than described for other high‐risk areas for oesophageal cancer. Recent studies suggest that RAR βand COX II is frequently downregulated and upregulated, respectively, in oesophageal squamous cell carcinomas. These results suggest potential therapeutic opportunities that can be exploited to combat the high incidence of this disease in Africa.
Human Genetic Susceptibility to Tuberculosis and Other Mycobacterial Diseases
Authors: Hoal Eileen G. 
Published: September 2003

AbstractThe existence of a genetic component in mycobacterial disease susceptibility is no longer in doubt and the investigations now being conducted aim to determine which genes are involved, to what extent, and in which disease phenotype they are relevant. In certain rare instances of susceptibility to poorly pathogenic mycobacteria, the genetic component is clear. The approaches employed to elucidate common disease susceptibility include linkage studies, particularly genome‐wide linkage analysis of both tuberculosis and leprosy, and association studies. A number of candidate genes have shown association with tuberculosis, and in many cases, on replication of the study, association has been confirmed in a disparate population, indicating the wider importance of the gene in the disease process. In other instances, associations appear to be particular to a population or a subtype of disease.
Bacterial Multidrug Resistance Mediated by a Homologue of the Human Multidrug Transporter P‐glycoprotein
Authors: Konings Wil N. , Poelarends Gerrit J. 
Published: September 2003

AbstractMost ATP‐binding cassette (ABC) multidrug transporters known to date are of eukaryotic origin, such as the P‐glycoproteins (Pgps) and multidrug resistance‐associated proteins (MRPs). Only one well‐characterized ABC multidrug transporter, LmrA, is of bacterial origin. On the basis of its structural and functional characteristics, this bacterial protein is classified as a member of the P‐glycoprotein cluster of the ABC transporter superfamily. LmrA can even substitute for P‐glycoprotein in human lung fibroblast cells, suggesting that this type of transporter is conserved from bacteria to man. The functional similarity between bacterial LmrA and human P‐glycoprotein is further exemplified by their currently known spectrum of substrates, consisting mainly of hydrophobic cationic compounds. In addition, LmrA was found to confer resistance to eight classes of broad‐spectrum antibiotics, and homologs of LmrA have been found in pathogenic bacteria, supporting the clinical and academic value of studying this bacterial protein. Current studies are focused on unraveling the mechanism by which ABC multidrug transporters, such as LmrA, couple the hydrolysis of ATP to the translocation of drugs across the membrane. Recent evidence indicates that LmrA mediates drug transport by an alternating two‐site transport mechanism.
Thiol Metabolism of the Trypanosomatids as Potential Drug Targets
Authors: Steenkamp Daniel J. 
Published: September 2003

AbstractTrypanosomatids produce significant amounts of four major low molecular mass thiols, trypanothione, glutathionylspermidine, glutathione, and ovothiol A. Of these, only glutathione is present in cells of the host. All four low molecular mass thiols are directly or indirectly maintained in a reduced state by trypanothione reductase. Available evidence, from gene disruption studies, indicate that this is an essential enzyme. Attempts to exploit trypanothione reductase as a chemotherapeutic target lead to the design of competitive and irreversible inhibitors of the enzyme. A promising route involves the design of redox cyclers interacting specifically with trypanothione reductase as subversive substrates. Progress in studies on the biosynthesis of ovothiol A is summarized.
HIV Receptors and Cellular Tropism
Authors: Weiss Robin A. 
Published: September 2003

AbstractViruses use specific cell surface receptors to bind to and subsequently gain entry into their host cells. Some retroviruses such as HIV‐1 and HIV‐2 utilize one receptor for high‐affinity binding (CD4), and a separate coreceptor to mediate fusion of the viral envelope with the cell membrane (CCR5 or CXCR4). The identification of these receptors explains the cellular tropism of HIV, and hence its pathogenesis leading to immune deficiency (T‐helper cell depletion), the wasting syndrome (macrophage infection), and dementia (microglia infection). HIV can infect cells by membrane fusion at the cell surface and by receptor‐mediated endocytosis. Knowledge of the HIV receptors has led to practical developments such as inhibitory drugs, reasons for genetic resistance to infection, and should inform the judicious choice of candidate vaccines.
Human Papillomavirus (HPV) Infection in Southern Africa: Prevalence, Immunity, and Vaccine Prospects
Authors: Williamson Anna‐Lise , Marais Dianne , Passmore Jo‐Ann , Rybicki Ed 
Published: September 2003

AbstractHuman papillomavirus (HPV) associated cancers are more prevalent in developing countries compared to developed countries. The major cancer caused by HPV is cervical cancer. The humoral immune response to HPV can be a marker of past infection but may also reflect persistent infection and cervical disease. IgA antibodies to HPV in oral fluid were also found to be markers of cervical disease. Cell mediated immunity is important in clearing HPV infection and for regression of the associated lesions: this means that women infected with HIV have a high prevalence of co‐infection with HPV. Good cervical screening programmes can control HPV associated cervical neoplasia. However, in countries such as South Africa, where these programmes are inadequate, there is a need for an HPV vaccine. The development of HPV vaccines is reviewed. There is a call for an inexpensive vaccine that will be accessible to the women that do not have access to adequate screening programmes and are therefore at the greatest risk of cervical cancer.