BiP (GRP78), an essential hsp70 resident protein in the endoplasmic reticulum

BiP is a constitutively-expressed resident protein of the endoplasmic, reticulum (ER) of all eucaryotic cells, and belongs to the highly conserved hsp70 protein family. In the ER, BiP is involved in polypeptide translocation, protein folding and presumably protein degradation as well. These functions are essential to cell viability, as has been shown for yeast. In this review, I will summarize the structural features of hsp70 proteins and focus on those experiments which revealed the biological function of BiP.     

Effects of pertussis toxin onα 1-agonist-mediated phosphatidylinositide turnover and myocardial cell hypertrophy in neonatal rat ventricular myocytes

Summary In neonatal rat ventricular myocytes pretreatment with pertussis toxin did not affect 1 M (–)-norepinephrine stimulation of inositol phosphates or myocardial cell hypertrophy as measured either by protein radiolabelling or by myocardial cell protein content. Thus guanine nucleotide protein (s) ADP-ribosylated by pertussis toxin do not play a role in two ₁-adrenoceptor-mediated processes, phosphatidylinositide turnover and induction of myocardial cell hypertrophy.     

Interaction of chloramphenicol and 181-1181-1181-1in barbital-anesthetized mice

Résumé L'augmentation de l'anesthésie produite par le barbital chez la souris traitée au ¹-tétrahydrocannabinol ( ¹-THC) à 10 ou 20 mg/kg par voie i.p. est accentuée d'une manière significative par le traitement préalable au chloramphénicol (CHPC) à 100 mg/kg, mais non pas par 50 mg/kg de ce composé injecté par voie i.p. Le CHPC seul n'a aucun effet. Le CHPC étant un inhibiteur des systèmes enzymatiques des microsomes hépatiques, on en a conclu que l'effet du ¹-THC sur le prolongement de la durée du sommeil au barbital est dû au composé parent plutôt qu'à l'un des produits de transformation biologique.     

Naloxone prevents the analgesic action of α-MSH in mice

Summary -MSH (0.1, 1, 10 g) was administered intracerebroventricularly and its action on pain sensitivity was investigated by the hot-plate method in mice. -MSH produced dose-dependent analgesia and this analgesic effect was prevented by naloxone (1 mg/kg, s.c.). It is possible that -MSH may play a role in the mechanism of pain through endogeneous opioid systems.     

Das Strukturbild der Arterienwand unter lebensnahen Präparationsbedingungen und seine physiologische und pathologische Bedeutung

Summary At first sight it seems impossible to obtain a picture of arterial structure fixed in the true conditions of life. The arterial wall particularly is exposed to severe forces of alteration at the moment of death. Even before autolysis and rigor mortis, it is submitted to a triple trauma: the sudden cessation of rhythmical pulsation, the emptying of the lumina and the blood coagulation. Nevertheless precisely, these factors give us a simple and relatively safetest for deciding whether a histological preparation corresponds to the true life conditions; we may assume this to be so when the lumen of small blood vessels is full ofuncoagulated blood. Studies on such preparations show that during life there are no particular annular and longitudinal muscle fibres in the arterial wall, it is rather theplasticity and activity of a unitary musculature which determines the appearance of variously oriented fibers in histological preparations. As for the elastic tissue, it appears as a continuous line, when in activity; curvatures or ruptures mean a limitation or suppression of the elastic function. Observations on the so-called regulating apparatus in arteries of man, completed by others on dogs under influence of adrenalin, lead one to consider the particular relationship of clear muscle cells and elastic elements as themorphological equivalent of vasoconstrictive action. These results call for a revision of some histological, histopathological and even physiological concepts, such as the accepted histological views on the existence of arterial closure apparatus. The aspects described as sphincters, Polster, bourrelets, valves are not permanent structures butsnapshots of moving parts of the arterial wall. The clear muscular cells named epitheloid cells, Quellzellen, Leiomyoblasts are muscle fibers quasi surprised by the fixation in theactive state.     

Horizontal gene transfer from Eukarya to Bacteria and domain shuffling: the α-amylase model

-Amylases are present in all kingdoms of the living world. Despite strong conservation of the tertiary structure, only a few amino acids are conserved in interkingdom comparisons. Animal -amylases are characterized by several typical motifs and biochemical properties. A few cases of such -amylases have been previously reported in some eubacterial species. We screened the bacterial genomes available in the sequence databases for new occurrences of animal-like -amylases. Three novel cases were found, which belong to unrelated bacterial phyla: Chloroflexus aurantiacus, Microbulbifer degradans, and Thermobifida fusca. All the animal-like -amylases in Bacteria probably result from repeated horizontal gene transfer from animals. The M. degradans genome also contains bacterial-type and plant-type -amylases in addition to the animal-type one. Thus, this species exhibits -amylases of animal, plant, and bacterial origins. Moreover, the similarities in the extra C-terminal domains (different from both the -amylase domain C and the starch-binding domain), when present, also suggest interkingdom as well as intragenomic shuffling.Received 17 October 2003; accepted 6 November 2003     

ω10-Lipoxygenase products of α-linolenic acid are esterified to phospholipids inHydra vulgaris

We have recently reported the occurrence of 9(R)-hydroxy-, 9(R)-hydroperoxy- and 9-keto-octadeca-10E,12Z,15Z-trienoic acids (9-HOTrE, 9-HPOTrE and 9-KOTrE) inHydra vulgaris, and their biosynthesis from -linolenic acid (-LA) through the action of an enantioselective 10(R)-lipoxygenase (10-LO). Here we describe the finding of these -LA metabolites as esters to the 2-position of phosphatidylcholine, phosphatidylethanolamine and, in trace amounts, phosphatidylinositol. Small amounts of a compound co-eluting with an authentic standard of 9(R)-hydroxy-octadeca-10E,12Z-dienoic acid, a metabolite potentially derived from the action of 10-LO on linoleic acid, were also found esterified with phospholipids. Since direct peroxidation of membrane lipids has been described, experiments were aimed at establishing whether -LA metabolite-containing phospholipids could originate, inH. vulgaris, from either spontaneous or 10-LO-catalyzed oxidation of phospholipid-bound -LA. Incubation of either unlabelled or radiolabelled PUFA-containing phosphoglycerides withH. vulgaris 10-LO did not result in their peroxidation. This suggests that -LA and LA metabolites are incorporated into glycerophospholipids after their formation by 10-LO, and that, as in mamals, membrane phospholipids may serve as a reservoir for these bioactive compounds. This is the first example in an invertebrate species of lipoxygenase products esterified to phosphoglycerides.     

Free radicals and aflatoxin biosynthesis

Summary The addition of some halogenated alkanes (bromotrichloromethane, carbontetrachloride and chloroform) to cultures ofA. parasiticus andA. flavus have shown a high stimulating effect on aflatoxin biosynthesis. When the production of aflatoxin increases during the stimulating effect the peroxidase activity is inhibited.Acknowledgments. Supported by Cassa di Risparmio di Roma, funds from Ministry of Education and Faculty of Science of La Sapienza Rome University.     

Nitrogenase activity in a transfilter culture of rhizobia with a non-leguminous plant callus culture: Transfer of fixed15N2 from bacteria toPortulaca callus

Summary A transfilter culture of the non-leguminous plantPortulaca grandiflora var. JR andRhizobium sp. cowpea 32H1 was established. Using¹⁵N₂-analysis we demonstrated that¹⁵N-containing substances produced by the bacteria passed through the membrane and¹⁵N was enriched in the plant cells.Acknowledgment. The authors wish to express their gratitude to Prof. H. Marschner and Dr G. Hentschel for the determination of the nitrogen-content of our samples by the Dumasmethod and for advice on the optic emission method. Drs J. Burton, Milwaukee, Wisc., and Tjepkema, Oregon State University, are thanked for generous gifts ofRhizobium sp. cowpea 32H1. This work was supported by the DFG.     

Tumor necrosis factor α in the pathogenesis of cerebral malaria

Physiologically in the brain, cytokines such as tumor necrosis factor-alpha (TN) are released by the immune system and can modulate neurological responses. Conversely, the central nervous system (CNS) is also able to modulate cytokine production. In the case of CNS disorders, cytokine release may be modified. Cerebral malaria (CM) is a complication of Plasmodium falciparum infection in humans and is characterized by a reversible encephalopathy with seizures and loss of consciousness. Central clinical signs are partly due to sequestration of parasitized red blood cells in the brain microvasculature due to interactions between parasite proteins and adhesion molecules. TNF is produced and released by host cells following exposure to various malarial antigens. The increase of TNF release is responsible for the overexpression of adhesion molecules. This article reviews the involvement of TNF in cerebral malaria and the relation with all the processes involved in this pathology. It shows that (i) TNF levels are increased in plasma and brain but with no clear correlation between TNF levels and occurrence and severity of CM; (ii) TNF is responsible for intercellular adhesion molecule-1 upregulation in CM, the relation being less clear for other adhesion molecules; (iii) TNF receptors are upregulated in CM, with TNF receptor 2 (TNFR2) showing a higher upregulation than TNFR1 in vivo; (iv) in murine CM, low doses of TNF seem to protect from CM, whereas excess TNF induces CM and anti-TNF therapies (antibodies, pentoxifylline) did not show any efficiency in protection from CM. Moreover, the involvement of lymphotoxin a, which shares with TNF the same receptors with similar affinity, appears to be an interesting target for further investigation.Received 4 December 2002; received after revision 7 February 2003; accepted 14 February 2003     

The cellular immune response to heat shock proteins

T lymphocytes, which are central to almost every immune response, frequently recognize microbial hsp60. Such cells could provide an early defense mechanism against pathogenic microbes. However, T cells also recognize epitopes of hsp60 shared by microbe and host. Not only conventional / T cells respond to hsp60; / T cells do so, as well. In fact, certain / T cells seem to have a particular preference for this molecule. Recognition of stressed host cells expressing hsp60 could facilitate the scavenger function of the T cell system. On the other hand, such recognition could be involved in autoimmune disease.     

Über 1-Halogenderivate desd-Glucosamins

Summary Treating-Pentaacetyl-d-glucosamin with ethereal hydrochloric acid leads to 1-Chloro-3,4,6-N-tetraacetyl-d-glucosamin, whose structure is proved by infra-red-spectra and transformation to known products.     

Hydrolysis of amino acid β-naphthylamides by aminopeptidases in the parotid gland

Zusammenfassung Die Aktivität der Aminopeptidasen in Ohrspeicheldrüsen wurde gemessen. Glycyl-Prolin-naphthylamid, Alanin-naphthylamid, Leucin-naphthylamid, Methionin-naphthylamid, und Arginin-naphthylamid wurden von der Mikrosomenfraktion und der löslichen Fraktion schnell gespalten. Das Glycyl-Prolin-naphthylamid spaltende Enzym war in Ohrspeicheldrüsen in relativ grösserer Menge vorhanden. Die Aufspaltung von Glycyl-Prolin-naphthylamid in Glycyl-Prolin und-Naphthylamin wurde papierchromatographisch nachgewiesen.     

Metabolic pathways of δ-aminolaevulinic acid inRhodopseudomonas spheroides

Summary Incorporation of -aminolaevulinic acid 5¹⁴C and 4¹⁴C into the inosine monophosphate pool and into porphyrins, was studied in cell suspensions ofR. spheroides. The results contradict a direct incorporation of -aminolaevulinic acid into the purine ring of nucleotides through -dioxovaleric acid. It would suggest a nonspecific incorporation after degradation of -aminolaevulinic acid without a transamination as a first reaction.     

The distribution of some enzymes involved in the steroidogenesis of hen's ovary

Riassunto È stata studiata con metodi istochimici la distribuzione della ⁵-3-idrossisteroide deidrogenasi ( ⁵-3-HSDH) e delle 17-idrossisteroide deidrogenasi (17-HSDH), DPN- e TPN-dipendenti, nell'ovario di gallina ovulante. Mentre la ⁵-3-HSDH è presente in tutti i tessuti a secrezione steroide dell'ovario, la 17-HSDH è localizzata solo nelle cellule della granulosa.     

Insulin stimulates sodium-potassium activated ATPase from rat hippocampus

Summary It is suggested that insulin is capable of activating cerebral NaK-ATPase in a dose-dependent manner.Supported by grants from Ministerium für Hoch- und Fachschulwesen der DDR.     

Kinetics of chemo-attraction of polymorphonuclear leukocytes towards N-formyl peptide studied with a novel polycarbonate (Nuclepore) membrane in the Boyden chamber

Summary The motile responses of human polymorphonuclear leukocytes (PMN) to N-formyl-methionyl-leucyl-phenylalanine (FMLP) in the Boyden chamber using a new sparse-pore polycarbonate membrane (pores 3 m in diameter and occupying 0.1% of surface area) were compared with those demonstrated by using a standard polycarbonate (Nuclepore) filtration membrane (pores 3 m in diameter and occupying 5% of surface area). Motility of PMN in gradients of FMLP using the new membrane was not influenced by chemokinetic effects of the factor, and the background migration of the cells was minimal. However, motility of PMN in gradients of FMLP using the standard membrane was found to be influenced by chemokinetic effects of the chemotactic factor, and the background or control migration (in the absence of chemotactic factor) of the cells was substantial. Greater directional migration of PMN according to steepness of the gradient of chemotactic factor was demonstrated with the use of the new membrane. The new membrane may be of considerable value in the further study of the chemotactic responses of PMN.     

16-β-methylprednisone from hecogenin

Zusammenfassung Es wird über die Herstellung des 16-Methylprednisons berichtet, welche vom Hecogenin ausgehend über ca. 15 Stufen durchgeführt wird. Als wichtige Zwischenstufe treten 5-Pregn-16-en-3-ol-11, 20-dion-Acetat und 16-Methylen-5-pregnan-3, 17-diol-11, 20-dion auf: letzteres wird durch eine stereospezifische katalytische Reduktion in das entsprechende 16-Methyl-derivat umgewandelt.     

Zur Genese hepatozellulärer Kerneinschlüsse bei Colchicinvergiftung

Summary The colchicin-induced nuclear inclusions are a postmitotic phenomena. Fusing chromosome vesicles often include a portion of cytoplasm, surrounded by persisting parts of the vesicle membranes (indirect or membraned n.i.). This membrane sometimes degenerates; the n.i. then lies free in the karyoplasm (secondarily direct or free n.i.).     

ER-to-Golgi transport and cytoskeletal interactions in animal cells

The endoplasmic reticulum (ER)-Golgi system has been studied using biochemical, genetic, electron and light microscopic techniques. We now understand many aspects of trafficking from the ER to the Golgi apparatus, including some of the signals and mechanisms for selective retention and retrieval of ER resident proteins and export of cargo proteins. Proteins that leave the ER emerge in export complexes or ER exit sites and accumulate in pleiomorphic transport carriers referred to sometimes as VTCs or intermediate compartments. These structures then transit from the ER to the Golgi apparatus along microtubules using the dynein/dynactin motor and fuse with the cis cisterna of the Golgi apparatus. Many proteins (including vSNAREs, ERGIC53/p58 and the KDEL receptor) must cycle back to the ER from pre-Golgi intermediates or the Golgi. We will discuss both the currently favored model that this cycling occurs via 50-nm COPI-coated vesicles and in vivo evidence that suggests retrograde trafficking may occur via tubular structures.