Bruno Maresca

Biology of antarctic fish

1 Ecology, Evolution and Life History.- Ecology of Notothenioid Fish in the Weddell Sea (With 8 Figures).- Morphological Adaptations and Mode of Life in High Antarctic Fish (With 6 Figures).- The Biological and Demographic Peculiarities of the Icefish Champsocephalus gunnari Lonnberg, 1905 from the Kerguelen Plateau (With 8 Figures).- Is the Growth of Polar Fish Limited by Temperature? (With 6 Figures).- Review of the Early Life History of Antarctic Notothenioid Fish (With 1 Figure).- Age Determination in Antarctic Fish (With 4 Figures).- Microstructural Analysis of Growth Patterns in the Early Life History of Antarctic Fishes (With 7 Figures).- The Fossil and Modern Fish Faunas of Antarctica: Evolution and Diversity (With 3 Figures).- The Contribution of the BIOMASS Program to Antarctic Marine Ecosystem Research (With 3 Figures).- 2 Physiology, Biochemistry and Molecular Biology.- The Sensory Biology of Notothenioid Fish (With 9 Figures).- Viscosity of Body Fluids from Antarctic Notothenioid Fish (With 9 Figures).- Low Temperature Limits Burst Swimming Performance in Antarctic Fish (With 6 Figures).- Respiratory and Cardiovascular Adaptations in Hemoglobin-Free Fish: Resolved and Unresolved Problems (With 2 Figures).- Structural and Mechanical Characteristics of the Heart of the Icefish Chionodraco hamatus (Lonnberg) (With 10 Figures).- Physiological Roles of High Lipid Content in Tissues of Antarctic Fish Species (With 5 Figures).- Biochemical Mechanisms of Cold Adaptation and Stenothermality in Antarctic Fish (With 10 Figures).- Polymerization of Microtubule Proteins from Antarctic Fish (With 6 Figures).- The Biochemistry of Oxygen Transport in Red-Blooded Antarctic Fish (With 2 Figures).

Hsp70 in parasites: as an inducible protective protein and as an antigen

The heat shock (HS) response is a general homeostatic mechanism that protects cells and the entire organism from the deleterious effects of environmental stresses. It has been demonstrated that heat shock proteins (HSP) play major roles in many cellular processes, and have a unique role in several areas of cell biology, from chronic degenerative diseases to immunology, from cancer research to interaction between host and parasites. This review deals with thehsp70 gene family and with its protein product, hsp70, as an antigen when pathogens infect humans. Members of HSP have been shown to be major antigens of many pathogenic organisms when they experience a major temperature shift upwards at the onset of infection and become targets for host B and T cells.

A temperature-sensitive strain ofHistoplasma capsulatum has an altered Δ9-fatty acid desaturase geneacid desaturase gene

We have isolated and characterized the Δ9-desaturase gene (Ole1), which codes for a key enzyme involved in regulating membrane fluidity in animal cells and microorganisms, from two strains ofHistoplasma capsulatum, one that is temperature-tolerant (G217B) and the other temperature-susceptible (downs). These pathogenic fungi are dimorphic in that they undergo a morphologic transition from the mycelial to yeast-like form when the temperature of incubation is switched from 25 to 37°C or when they infect a susceptible host. The coding sequences of the two genes, both containing an intron of 93 nucleotides, arevirtually identical and analogous to the Δ9-desaturase gene ofSaccharomyces cerevisiae and those of the rat, mouse and human.Ole1 transcription of the thermotolerant G217B and thermosensitive Downs strains is similar in yeast phase cells and during the temperature shift down from 34, 37, or 40 to 25°C (yeast-to-mycelia transition). Nevertheless, Δ9-desaturase gene is transcriptionally inactive in mycelia of G217B at 25°C while it is actively transcribed in the Downs strain at the same temperature. These results are in agreement with the finding that membranes of the Downs strain have a higher level of oleic acid. The differential expression of Δ9-desaturase genes is discussed in relationship to differences in thermosensitivity in the fungal isolates and in regulating the level of expression of heat shock genes.

Acquired thermotolerance following heat shock protein synthesis prevents impairment of mitochondrial ATPase activity at elevated temperatures in Saccharomyces cerevisiae

The complex molecular response of cells to sudden temperature changes is a well-characterized phenomenon. Although it is clear that the induction of heat shock proteins provides protection from heat in all of the organisms so far tested, very little is known about the role that this set of proteins plays in cellular homeostasis. Recently, putative roles for hsp60 and hsp70-like proteins have been proposed in Saccharomyces cerevisiae. hsp70-like proteins have been shown to be necessary for translocation of precursor polypeptides into mitochondria and endoplasmic reticulum, while hsp60 is required for the assembly of precursor polypeptides into oligomeric complexes following incorporation into the mitochondrial matrix. In this paper, we report that a brief temperature shock (44 degrees C) impairs coupling of oxidative phosphorylation in S. cerevisiae as measured indirectly by the Cl-CCP/oligomycin assay. Furthermore, at high temperature oligomycin stimulates rather than inhibits oxygen uptake under nonthermotolerant conditions. Pretreatment of cells for a short period of time at 37 degrees C, prior to exposure to higher temperatures rescues the capacity to maintain coupling between oxidative phosphorylation and electron transport. Inhibition of cytoplasmic RNA or protein synthesis during heat shock prevents the protection of this mitochondrial activity. We propose that one of the roles of the induction of heat shock proteins (or related activities) is to protect mitochondrial ATPase activity under conditions of further increase in temperature.

Heat shock and cold adaptation in Antarctic fishes: a molecular approach

Abstract 1. 1. The restriction patterns of three different Antarctic fish DNA ( P. bernacchi, N. rossi and C. kathleene ) have been analysed. 2. 2. The restricted DNAs have been probed for the presence of the heat shock 70 sequence (hsp70) by using the corresponding Drosophila sequence. The three patterns are closely related for the presence of several bands in common, though a closer arrangement for the hsp70 gene is present in P. bernacchi and N. rossi . The analysis with different stringency conditions has also suggested that in these fishes more than one copy of hsp70 per genome is present. 3. 3. Poly-A RNA analysis with Northern blot have shown that the hsp70 gene is transcribed, upon temperature increase, between 5 and 12°C with a maximum of expression at 8°C.

Molecular biology and its application to medical mycology.

Molecular Biology of Yeast.- Cell Cycle Regulation in Fission Yeast.- Yeast Genes Overcoming Growth Arrest Induced by 1,10-Phenanthroline.- Reverse Genetics in a Non-Conventional Yeast, Candida maltosa.- The Complement C3D-Binding Receptor (CR2) of Candida albicans: Cloning and Sequence Analysis of a Gene Fragment Homologous with a Human CR2 cDNA Clone.- Biology, Physiology, Biochemistry and Molecular Genetics of Trichosporon Yeasts.- Physiological Functions of Vacuoles in Yeast: Mechanism of Sequestration of Metabolites and Proteins into Vacuoles.- Characterization of a Candida albicans-Specific DNA Fragment.- Recent Advances in the Molecular Biology of Cryptococcus neoformans.- Molecular Biology of Kluyveromyces lactis.- Gene Regulatory Circuits in S. cerevisiae as a Tool for the Identification of Heterologous Eukaryotic Regulatory Elements.- Molecular Biology of Filamentous Fungi.- Molecular Breeding in Filamentous Fungi with Emphasis on Aspergilli.- TubB ?-Tubulin is Essential for Sexual Development in Aspergillus nidulans.- The Heat Shock Response of Neurospora crassa.- Blue Light Regulated Expression of Geranylgeranyl Pyrophosphate Synthetase (Albino-3) Gene in Neurospora crassa.- Expression of Genes for the Biosynthesis of Penicillin.- New Tools and Prospectives for Medical Mycology.- Imaging of the Yeast Killer Phenomenon.- cDNA Cloning of Candida albicans Aspartic Proteinase and Its Diagnostic Application.- Molecular Biotyping of Candida in Experimental and Clinical Studies.- Homoserine Dehydrogenase as a Selective Target Molecule for Antifungal Action.- Molecular Mechanisms of Antifungal Activity and Fungal Resistence: Focus on Inhibitors of Ergosterol Biosynthesis.- Molecular Studies on Azole Sensitivity in Fungi.- Antifungal Chemotherapy and Drug Strategies: Projected Clinical Needs.- Funding Medical Mycology: Strategies for Attracting the Private Sector.- Fungal Morphogenesis.- Chromosomal Organization of Histoplasma capsulation.- Chitin, Chitin Synthase and Chitin Synthase Conserved Region Homologues in Wangiella dermatitidis.- Heat Shock Response and Adaptation during Morphogenesis in Histoplasma capsulatum.

Different temperature dependences of oxidative phosphorylation in the inner and outer layers of tuna heart ventricle

Summary1.The oxidative phosphorylation and the temperature dependence of mitochondria prepared from the outer compact layer and the inner spongy layer of adult tuna heart ventricle have been examined.2.Mitochondria of the inner layer show higher succinoxidase and NADH-oxidase activities as compared with those of the outer layer.3.Arrhenius plots for succinate oxidation by phosphorylating mitochondria show that the temperature dependence of the inner layer is higher than that of the outer layer.4.Experiments performed with disrupted non-phosphorylating mitochondria demonstrate that this difference in temperature dependence of the two cardiac compartments depends on the integrity of the mitochondrial membranes.5.These findings are discussed in relation to the physiology of the fish.

Do Antarctic Fish Respond to Heat Shock

Temperature is a major environmental factor requiring adaptive responses and it is a central selective element in speciation. One of the best known and complex mechanisms that is primarily involved in protecting cells from various forms of stresses, such as temperature, is the stress (heat shock) response [1], For poikilotherms, fluctuations in environmental temperatures can be fatal. Sudden drops in temperature can lead to a reduction in membrane fluid state that, in turn, causes cessation of normal functions. Unless rapidly corrected, such alterations will lead to physiological damage and, ultimately, to death. Several essential cellular activities depend on proper membrane functionality [2]. For elevated environmental temperatures, some of the problems encountered during chilling are also relevant. There still exist the dual needs of being able to “sense” the elevated environmental temperature and to couple this detection to the induction of gene expression — such as for heat shock genes. Recently, there have been several lines of evidence which suggest that changes in response to an abrupt rise in the environmental temperature may have analogies with chilling adaptation. Thus, membrane lipid composition, as well as the dynamic state of membrane lipids, represent the basic elements for membrane functionality. Membranes, indeed, have multiple physical properties which permit the cell to sense environmental changes.

Incidence of histoplasmin skin test reactivity in somalia: an epidemiological study

Histoplasmosis is an important systemic mycotic infection with a wide geographic distribution. Its occurrence has been mostly studied in the US (6) and in Central America (6), but very little is known about its distribution in Africa, where a specific variant exists. Skin test surveys in the Democratic Republic of Somali indicate that Histoplasma capsulatum or a closely related agent has a focus in this east African country.

Heat Shock and Adaptation During Temperature-Activated Dimorphism in the Fungus Histoplasma capsulatum

Histoplasma capsulatum is the causative agent of histoplasmosis, a systemic fungal disease worldwide in occurrence, and the most common respiratory mycotic infection affecting humans and animals (Schwarz 1981). Several fungi, in particular those pathogenic such as H.capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis etc., can assume a filamentous or unicellular morphology in response to changes in the environmental conditions (Maresca and Kobayashi 1989). H.capsulatum grows as mycelia in soil while the yeast phase is the only form present in patients. In laboratory conditions, dimorphism is directly and reversibly controlled by temperature changes. The temperature-induced transition and the events in establishment of infection seem to be intimately correlated. In fact, the temperature works not only as a signal for adaptation through the induction of a heat shock-like phenomenon, but also in triggering the phase transition. The role that the heat shock response plays during the differentiation process and in the adaptation to high temperature in H.capsulatum will be discussed here.