[leish-l] Fwd: Articles found by RefScout 09/02/2005 -5/2005 part 3.

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This is RefScout-Newsletter 5/2005.






Due to more than 100 requests your newsletter has been split. This is part 3.




REQUEST: [ leishmania ]

(200 articles match this request. 108 articles matching other requests removed.
80 articles are sent in previous email(s))



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PMID: 8923956
 

TITLE: Enzymatic synthesis of UDP-galactofuranose and an assay for
UDP-galactopyranose mutase based on high-performance liquid chromatography.

AFFILIATION: Department of Microbiology, Colorado State University, Fort
Collins
80523-1677, USA.

REFERENCE: Anal Biochem 1996 Nov 242(1):1-7

A method to prepare UDP-galactofuranose (UDP-Galf) free of UDP-
galactopyranose (UDP-Galp) is described. The UDP-Galf is synthesized 
enzymatically from UDP-Galp using the enzyme UDP-galactopyranose mutase
. Treatment of UDP-Galp with the enzyme yields an equilibrium mixture of
 UDP-Galp and UDP-Galf in which UDP-Galf is approximately 7%. In spite 
of its low yield, the UDP-Galf is readily purified from starting UDP-
Galp using a Dionex PA-100 ion exchange HPLC column. The purified UDP-
Galf was characterized by chemical degradations, by electrospray mass 
spectrometry, and by several nuclear magnetic resonance techniques. In 
addition, an HPLC assay for the enzyme UDP-galactopyranose mutase is 
presented that requires 0.5 microgram of UDP-Galf per assay and can be 
used for both qualitative and quantitative measurements of the enzyme 
activity. These procedures should thus aid in the characterization of 
the enzymes involved in galactofuranosyl biosynthesis for the cell walls
 of Mycobacteria, for the lipophosphoglycan of Leishmania, and for other
 microorganisms where galactofuranosyl residues are found.




PMID: 8629027
 

TITLE: An enhanced immune response in mice lacking the transcription factor
NFAT1.

AFFILIATION: Neurogenetics Program, Department of CNS Research,
Hoffmann-LaRoche, Nutley, NJ 07110, USA.

REFERENCE: Science 1996 May 272(5263):892-5

Transcription factors of the NFAT family are thought to play a major 
role in regulating the expression of cytokine genes and other inducible 
genes during the immune response. The role of NFAT1 was investigated by 
targeted disruption of the NFAT1 gene. Unexpectedly, cells from NFAT1
 -/- mice showed increased primary responses to Leishmania major and 
mounted increased secondary responses to ovalbumin in vitro. In an in 
vivo model of allergic inflammation, the accumulation of eosinophils and
 levels of serum immunoglobulin E were increased in NFAT1 -/- mice. 
These results suggest that NFAT1 exerts a negative regulatory influence 
on the immune response.




PMID: 8784772
 

TITLE: Use of the green fluorescent protein as a marker in transfected
Leishmania.

AFFILIATION: Department of Biological Chemistry and Molecular Pharmacology,
Harvard Medical School, Boston, MA 02115, USA.

REFERENCE: Mol Biochem Parasitol 1996 Apr 77(1):57-64

We have tested the suitability of the green fluorescent protein (GFP) of
 Aequorea victoria as a marker for studies of gene expression and 
protein targeting in the trypanosomatid parasite Leishmania. Leishmania 
promastigotes expressing GFP from episomal pXG vectors showed a bright 
green fluorescence distributed throughout the cell, readily 
distinguishable from control parasites. Transfection of a modified GFP 
gene containing GC-rich synonymous codons and the S65T mutation (GFP+) 
yielded a much higher fluorescence. FACS analysis revealed a clear 
quantitative separation between GFP-transfected and control parasites, 
with pXG-GFP+ transfectants showing fluorescence signals more than 100-
fold background. Episomal DNAs could be recovered from small numbers of 
fixed cells, showing that GFP could be used as a convenient screenable 
marker for FACS separations. GFP was fused to the C-terminus of the LPG1
 protein, which retained its ability to restore LPG expression when 
expressed in the lpg- R2D2 mutant of L. donovani. The LPG1(GFP) fusion 
was localized to a region situated between the nucleus and kinetoplast; 
its pattern was similar to that of LPG2, which is known to be located in
 the Golgi apparatus. This is notable as LPG1 participates in the 
biosynthesis of the glycan core of the LPG GPI anchor, whereas protein 
GPI anchor biosynthesis occurs in the endoplasmic reticulum. These 
studies suggest that the GFP will be a broadly useful marker in 
Leishmania.








PMID: 7722452
 

TITLE: Interleukin 12 signaling in T helper type 1 (Th1) cells involves
tyrosine
phosphorylation of signal transducer and activator of transcription (Stat)3 and
Stat4.

AFFILIATION: Department of Pathology, Washington University School of Medicine,
St. Louis, Missouri 63110, USA.

REFERENCE: J Exp Med 1995 May 181(5):1755-62

Interleukin 12 (IL-12) initiates the differentiation of naive CD4+ T 
cells to T helper type 1 (Th1) cells critical for resistance to 
intracellular pathogens such as Leishmania major. To explore the basis 
of IL-12 action, we analyzed induction of nuclear factors in Th1 cells. 
IL-12 selectively induced nuclear DNA-binding complexes that contained 
Stat3 and Stat4, recently cloned members of the family of signal 
transducers and activators of transcription (STATs). While Stat3 
participates in signaling for several other cytokines, Stat4 was not 
previously known to participate in the signaling pathway for any natural
 ligand. The selective activation of Stat4 provides a basis for unique 
actions of IL-12 on Th1 development. Thus, this study presents the first
 identification of the early events in IL-12 signaling in T cells and of
 ligand activation of Stat4.




PMID: 7957243
 

TITLE: A super-family of medium-chain dehydrogenases/reductases (MDR).
Sub-lines
including zeta-crystallin, alcohol and polyol dehydrogenases, quinone
oxidoreductase enoyl reductases, VAT-1 and other proteins.

AFFILIATION: Department of Medical Biochemistry and Biophysics, Karolinska
Institutet, Stockholm, Sweden.

REFERENCE: Eur J Biochem 1994 Nov 226(1):15-22

The protein super-family of medium-chain alcohol dehydrogenases (and 
glutathione-dependent formaldehyde dehydrogenase), polyol dehydrogenases
, threonine dehydrogenase, archaeon glucose dehydrogenase, and eye lens 
reductase-active zeta-crystallins also includes Escherichia coli quinone
 oxidoreductase, Torpedo VAT-1 protein, and enoyl reductases of 
mammalian fatty acid and yeast erythronolide synthases. In addition, two
 proteins with hitherto unknown function are shown to belong to this 
super-family of medium-chain dehydrogenases and reductases (MDR). 
Alignment of zeta-crystallins/quinone oxidoreductases/VAT-1 reveals 38 
strictly conserved residues, of which approximately half are glycine 
residues, including those at several space-restricted turn positions and
 critical coenzyme-binding positions in the alcohol dehydrogenases. This
 indicates a conserved three-dimensional structure at the corresponding 
parts of these distantly related proteins and a conserved binding of a 
coenzyme in the two proteins with hitherto unknown function, thus 
ascribing a likely oxidoreductase function to these proteins. When all 
forms are aligned, including enoyl reductases, a zeta-crystallin 
homologue from Leishmania and the two proteins with hitherto unknown 
function, only three residues are strictly conserved among the 106 
proteins characterised within the superfamily, and significantly these 
residues are all glycines, corresponding to Gly66, Gly86 and Gly201 of 
mammalian class I alcohol dehydrogenase. Notably, these residues are 
located in different domains. Hence, a distant origin and divergent 
functions, but related forms and interactions, appear to apply to the 
entire chains of the many prokaryotic and eukaryotic members. 
Additionally, in the zeta-crystallins/quinone oxidoreductases, a highly 
conserved tyrosine residue is found. This residue, in the three-
dimensional structure of the homologous alcohol dehydrogenase, is 
positioned at the subunit cleft that contains the active site and could 
therefore be involved in catalysis. If so, this residue and its role may
 resemble the pattern of a conserved tyrosine residue in the different 
family of short-chain dehydrogenases/reductases (SDR).




PMID: 1323839
 

TITLE: Defective stimulus-response coupling in human monocytes infected with
Leishmania donovani is associated with altered activation and translocation of
protein kinase C.

AFFILIATION: Department of Medicine, University of British Columbia Faculty of
Medicine, Vancouver, Canada.

REFERENCE: Proc Natl Acad Sci U S A 1992 Aug 89(16):7481-5

Stimulus-response coupling through protein kinase C (PKC) was shown to 
be defective in mononuclear phagocytes (M phi) infected with Leishmania 
donovani. Phorbol 12-myristate 13-acetate (PMA)-induced oxidative burst 
activity and protein phosphorylation were markedly attenuated in 
infected M phi. These results were not explained either by quantitative 
alterations in amounts of PKC or by altered phorbol ester binding but 
were related to defects in kinase activation. Analysis in vitro of the 
kinetic properties of PKC from infected M phi revealed an approximately 
2-fold increase in the concentration of 1,2-dioleoyl-rac-glycerol 
required to achieve half-maximal kinase activation. Evidence for 
abnormal PKC activation in vivo was reflected by attenuation of PMA-
induced translocation of enzyme to the particulate fraction of infected 
cells. These results provide direct evidence that infection with 
Leishmania inhibits activation of, and therefore intracellular signaling
 dependent on, PKC. Inhibition of stimulus-response coupling through PKC
 provides a basis for understanding impairment of cellular activation by
 Leishmania and may contribute to chronic infection.








PMID: 1377218
 

TITLE: Short amino acid sequences derived from C1q receptor (C1q-R) show
homology with the alpha chains of fibronectin and vitronectin receptors and
collagen type IV.

AFFILIATION: Department of Medicine, State University of New York, Stony Brook.

REFERENCE: J Leukoc Biol 1992 Jun 51(6):546-56

The human C1q receptor (C1q-R) is a 65-70-kd, highly acidic, hydrophobic
 glycoprotein that is expressed on a wide variety of cell surfaces. 
Although the C1q-R itself appears to bind preferentially to C1q, the 
region of the ligand to which C1q-R binds is the primary binding site 
for several other molecules, including fibronectin, laminin, and C1q 
inhibitor (chondroitin 4-sulfate proteoglycan) as well as the complement
 C1r2C1s2 tetramer. In order to further characterize the C1q-R molecule 
with regard to its structure and function, highly purified C1q-R was 
obtained from Raji cells using DEAE-Sephacel and C1q-Sepharose CL-4B 
chromatography. Studies performed with 125I-labeled C1q-R demonstrated 
that whereas the C1q-R molecule binds poorly to a variety of human 
collagens including types II, III, and V, markedly enhanced binding is 
observed with type IV collagen and moderately enhanced binding with type
 I collagen. Amino acid composition studies show that the C1q-R molecule
 contains approximately 44% hydrophobic and 12.6% hydrophilic residues 
with a ratio of negatively charged to positively charged residues of 
about 2:1. Treatment of 125I-labeled C1q-R with endoglycosidase F lowers
 the apparent molecular size from 70 to 58 kd, whereas endoglycosidase H
 lowered the size to 64 kd. Treatment with neuraminidase, on the other 
hand, shifted the size of C1q-R to 60 kd. These results suggest the 
presence of several highly sialylated complex-type or high mannose-type 
N-linked oligosaccharide side chains. Because purified C1q-R has a 
blocked amino terminus, amino acid sequences representing internal 
fragments of the molecule were generated by electroblotting and in situ 
enzymatic digestion. When these short sequences were searched against 
the National Biomedical Research Foundation computer data base, a seven-
amino-acid sequence, VSWQGQI, showed significant homology (100% and 80% 
in a five-amino-acid overlap, respectively) with the alpha chains of the
 human fibronectin (alpha 5 beta 1) and vitronectin (alpha v beta 3) 
receptors, and to a lesser degree with epidermal growth factor receptor 
and T cell receptor. A second sequence, ISEDNIR, showed homology with 
mouse collagen type IV (86% in a six-amino-acid overlap), calmodulin (60
% in a seven-amino-acid overlap), and a Leishmania major surface antigen
, gp63. These observations seem to predict that C1q-R has pockets of 
conserved sequences that are similar to those not only present in its 
ligand(s) but also in other cell surface receptors that may, in part, 
fulfill similar functions.




PMID: 2668758
 

TITLE: Methylglyoxal-catabolizing enzymes of Leishmania donovani promastigotes.

AFFILIATION: Department of Biochemistry, University College of Science,
University of Calcutta, West Bengal, India.

REFERENCE: Mol Biochem Parasitol 1989 Jun 35(1):21-9

Methylglyoxal is a toxic metabolite with growth inhibitory properties 
against Leishmania donovani promastigotes. We have shown in the present 
study that both log and stationary phase promastigotes of L. donovani 
can catabolize methylglyoxal to D-lactate as the major end product. The 
specific activity of methylglyoxal reductase was found to be the highest
 of all the catabolic enzymes. In contrast, the anabolic pathway for 
methylglyoxal could not be detected. Moreover, when control 
promastigotes or promastigotes in which the glycolytic pathway was 
inhibited were incubated with glucose, glycerol or dihydroxyacetone 
phosphate as energy source, neither methylglyoxal nor D-lactate could be
 detected.




PMID: 2424909
 

TITLE: Mechanisms of action of pyrazolopyrimidines in Leishmania donovani.

REFERENCE: J Biol Chem 1986 Jul 261(20):9412-5

We investigated the antileishmanial actions of the pyrazolopyrimidines 
allopurinol (4-hydroxypyrazolo[3,4-d]pyrimidine), thiopurinol (4-
thiopyrazolo[3,4-d]pyrimidine), and aminopurinol (4-aminopyrazolo[3,4-d]
pyrimidine). These compounds affect several metabolic processes. The 
first is the inhibition of GMP reductase by the IMP analogues 
allopurinol ribonucleoside monophosphate and thipurinol ribonucleoside 
monophosphate which reduces the organism's ability to synthesize ATP 
from guanine. Second, interconversion of adenine nucleotides to guanine 
nucleotides, is curtailed by the inhibition of IMP dehydrogenase by 
these same IMP analogues. Third, the IMP analogues reduce intracellular 
UTP content. The fourth affect is increased catabolism of RNA and 
consequent reduction of protein synthesis. This latter effect is due to 
the adenine nucleotide analogues aminopurinol ribonucleoside mono-, di
-, and/or triphosphates, metabolic products of both allopurinol and 
aminopurinol.








PMID: 6732835
 

TITLE: Monophosphates of formycin B and allopurinol riboside. Interactions with
leishmanial and mammalian succino-AMP synthetase and GMP reductase.

REFERENCE: Biochem Pharmacol 1984 May 33(10):1611-7

Formycin B 5'-monophosphate (Form B-MP) and allopurinol riboside 5'-
monophosphate ( HPPR -MP) are isomers of IMP that are metabolically 
produced when Leishmania spp. are incubated with the antileishmanial 
agents formycin B and allopurinol or allopurinol riboside. The 
interactions of Form B-MP with succino -AMP synthetase and GMP reductase
 from both leishmanial and mammalian sources were compared with the data
 of earlier studies with HPPR -MP. Both analogs could substitute for IMP
 as a substrate for succino -AMP synthetase isolated from Leishmania 
donovani. The V'max values of Form B-MP and HPPR -MP were about 1% of 
the V'max of IMP. Only Form B-MP (and not HPPR -MP) could serve as an 
alternative substrate for mammalian succino -AMP synthetase. The V'max 
of Form B-MP was 40% that of IMP. The corresponding analogs of AMP, ADP 
and ATP were produced when Formycin B was incubated with mouse L cells. 
The Formycin A residue was incorporated into the cellular RNA. The 
amount of Formycin A-TP produced (relative to ATP) in mouse L cells was 
considerably less than that produced in Leishmania spp. Both Form B-MP 
and HPPR -MP were inhibitors of partially purified GMP reductase from L
. donovani. The binding of Form B-MP and HPPR -MP to human GMP reductase
 was 40- and 100-fold weaker, respectively, than the binding to 
leishmanial GMP reductase. Pretreatment of promastigotes of L. donovani 
with either allopurinol or Formycin B resulted in greater than 95% 
reduction of the incorporation of the radiolabel from [14C]xanthine into
 ATP and greater than 80% reduction of the incorporation of the label 
into GTP. The HPPR -MP and Form B-MP present in these cells may have 
inhibited the leishmanial succino -AMP synthetase and GMP reductase. The
 analogs had little or no effect on the pool sizes of ATP and GTP of 
either mouse L cells or L. donovani.




PMID: 7159467
 

TITLE: Guanosine 5'-monophosphate reductase from Leishmania donovani. A
possible
chemotherapeutic target.

REFERENCE: Biochem Pharmacol 1982 Dec 31(23):3891-7

GMP reductase was highly purified from promastigotes of Leishmania 
donovani by chromatography on a single DEAE-cellulose column. Bimodal 
substrate saturation curves resulted in a 1/v versus 1/[GMP] plot that 
curved downward above 40 microM GMP. The kinetic constants were, 
therefore, obtained with GMP below this concentration. The K'm for GMP 
was 21 microM at pH 6.9. The enzyme was very sensitive to activation by 
GTP. At 20 microM GMP, a maximum of 600% activation occurred at 100 
microM GTP. Half-maximal activation occurred at 8 microM GTP. GTP at 100
 microM did not affect the K'm for GMP but did increase its V'max by 7-
fold. Xanthosine monophosphate (XMP) and IMP analogs served equally well
 as competitive inhibitors versus GMP. The inhibition by the analogs and
 the activation by GTP were mutually antagonistic processes. The 
inhibition by the IMP analogs, allopurinol nucleotide and thiopurinol 
nucleotide is of chemotherapeutic interest because these compounds were 
shown previously to be produced in Leishmania from the anti-leishmanial 
agents allopurinol and thiopurinol. These nucleotides were 100- and 20-
fold, respectively, more potent inhibitors of GMP reductase from L. 
donovani than of the corresponding enzyme from human erythrocytes.




PMID: 6211617
 

TITLE: A comparative study of Leishmania mexicana amastigotes and
promastigotes.
Enzyme activities and subcellular locations.

REFERENCE: Mol Biochem Parasitol 1982 Mar 5(3):199-211

Leishmania mexicana mexicana amastigotes have been shown to contain 
greater activities than promastigotes of the enzymes that catalyse the 
beta-oxidation of fatty acids, but lower activities of several 
glycolytic enzymes, with the activity of pyruvate kinase being 
especially low. The results suggest the beta-oxidation of fatty acids is
 relatively more important to Leishmania amastigotes than promastigotes
, whereas the reverse is true for glycolysis. Succinic dehydrogenase and
 peptidase activities were much higher in promastigotes than amastigotes
. The activities of glucose-6-phosphatase, fructose-1,6-bisphosphatase, 
acid phosphatase and glucose-6-phosphate dehydrogenase varied less, 
although in each case the activity was significantly lower in the 
mammalian stage. A method for lysing and fractionating L. m. mexicana 
promastigotes has been developed. Using this procedure it has been 
established that many of the glycolytic and functionally related enzymes
 are located in cell organelles, that hexokinase is intimately connected
 with the particulate part of the parasite, and that the microsomal 
fraction of L. m. mexicana is very different in composition from the 
microsomes of mammalian liver cells.




REQUEST: [ sand fly ]

(9 articles match this request. 8 articles matching other requests removed)



********************************************************************************************************************

 The following references are revised files and are brought to you in
accordance
to license agreement with the NLM.

********************************************************************************************************************


PMID: 10229701
 

TITLE: Salivary glands of the sand fly Phlebotomus papatasi contain
pharmacologically active amounts of adenosine and 5'-AMP.

AFFILIATION: Laboratory of Parasitic Diseases, NIAID, National Institutes of
Health, Building 4, Room 126, Bethesda, MD 20892-0425, USA.
Jribeiro at Atlas.Niaid.NIH.Gov

REFERENCE: J Exp Biol 1999 Jun 202(Pt 11):1551-9

Salivary gland homogenates of the sand fly Phlebotomus papatasi contain 
large amounts of adenosine and 5'-AMP, of the order of 1 nmol per pair 
of glands, as demonstrated by liquid chromatography, ultraviolet 
spectrometry, mass spectrometry and bioassays. These purines, 75-80 % of
 which are secreted from the glands following a blood meal, have 
vasodilatory and anti-platelet activities and probably help the fly to 
obtain a blood meal. Salivary 5'-AMP is also responsible for the 
previously reported protein phosphatase inhibitor in the salivary glands
 of P. papatasi, which is shown to be artifactual in nature as a result 
of allosteric modification by AMP of the phosphatase substrate used (
phosphorylase a).




REQUEST: [ sandfly ]

(10 articles match this request. 9 articles matching other requests removed)



PMID: 15642000
 

TITLE: Altitudinal variation in morphometric and molecular characteristics of
Phlebotomus papatasi populations.

AFFILIATION: Department of Biology, Faculty of Science, Hacettepe University,
Turkey.

REFERENCE: Med Vet Entomol 2004 Dec 18(4):343-50

Abstract. Four populations of the phlebotomine sandfly Phlebotomus (
Phlebotomus) papatasi (Scopoli) (Diptera: Psychodidae), in different 
ecoregions at altitudes between 368 and 1117 m in the Sanliurfa Province
 of Turkey, were compared using morphometric and isoenzyme analyses. A 
similarity phenogram obtained from allozyme data showed that 
heterozygosity was extremely low, particularly for the alleles which 
were found to be completely fixed in populations at Hamdun (HMD) and 
Alitas (ALT). Populations at Akcakale (AKL) and ALT branched as a 
separate group from populations at Hayatiharrani (HHR) and HMD. The ALT 
population at the highest altitude (1117 m), and the HHR population (488
 m) were clustered distinctly when linear measurements of 46 
morphological characteristics were examined. A upgma (unweighted pair-
group method using arithmetic averages) phenogram also showed that ALT 
and HHR clustered separately, whereas AKL and HMD formed another group.















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