scholarly journals Putative morphology of Neoehrlichia mikurensis in salivary glands of Ixodes ricinus

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jaroslav Ondruš ◽  
Pavel Kulich ◽  
Oldřich Sychra ◽  
Pavel Široký
Keyword(s):  
Salivary Glands ◽  
Ixodes Ricinus ◽  
Mammalian Cells ◽  
Intracellular Pathogen ◽  
Transmission Electron ◽  
Ultrathin Sections ◽  
In Vitro Feeding ◽  
Neoehrlichia Mikurensis ◽  
Electron Lucent

Abstract Neoehrlichia mikurensis is an emerging tick-borne intracellular pathogen causing neoehrlichiosis. Its putative morphology was described in mammalian, but not in tick cells. In this study, we aim to show the presumptive morphology of N. mikurensis in salivary glands of engorged females of Ixodes ricinus. To accomplish this, we collected I. ricinus ticks in a locality with a high N. mikurensis prevalence, allowed them to feed in the artificial in vitro feeding system, dissected salivary glands and screened them by PCR for N. mikurensis and related bacteria. Ultrathin sections of salivary glands positive for N. mikurensis but negative for other pathogens were prepared and examined by transmission electron microscopy. We observed two individual organisms strongly resembling N. mikurensis in mammalian cells as described previously. Both bacteria were of ovoid shape between 0.5–0.8 μm surrounded by the inner cytoplasmic and the rippled outer membrane separated by an irregular electron-lucent periplasmic space. Detection of N. mikurensis in salivary glands of I. ricinus suggests that this bacterium uses the “salivary pathway of transmission” to infect mammals.

scholarly journals Antileishmanial Activity of a Linalool-Rich Essential Oil from Croton cajucara

2003 ◽  
Vol 47 (6) ◽  
pp. 1895-1901 ◽  
Author(s):  
Maria do Socorro S. Rosa ◽  
Ricardo R. Mendonça-Filho ◽  
Humberto R. Bizzo ◽  
Igor de Almeida Rodrigues ◽  
Rosangela Maria A. Soares ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Essential Oil ◽  
Mammalian Cells ◽  
Morphological Changes ◽  
Peritoneal Macrophages ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Mouse Peritoneal Macrophages ◽  
Croton Cajucara

ABSTRACT The in vitro leishmanicidal effects of a linalool-rich essential oil from the leaves of Croton cajucara against Leishmania amazonensis were investigated. Morphological changes in L. amazonensis promastigotes treated with 15 ng of essential oil per ml were observed by transmission electron microscopy; leishmanial nuclear and kinetoplast chromatin destruction, followed by cell lysis, was observed within 1 h. Pretreatment of mouse peritoneal macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these macrophages and L. amazonensis, with a concomitant increase by 220% in the level of nitric oxide production by the infected macrophages. Treatment of preinfected macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these cells and the parasites, which led to a 60% increase in the amount of nitric oxide produced by the preinfected macrophages. These results provide new perspectives on the development of drugs with activities against Leishmania, as linalool-rich essential oil is a strikingly potent leishmanicidal plant extract (50% lethal doses, 8.3 ng/ml for promastigotes and 8.7 ng/ml for amastigotes) which inhibited the growth of L. amazonensis promastigotes at very low concentrations (MIC, 85.0 pg/ml) and which presented no cytotoxic effects against mammalian cells.

scholarly journals Killing of Trypanozoon Parasites by the Equine Cathelicidin eCATH1

2016 ◽  
Vol 60 (5) ◽  
pp. 2610-2619 ◽  
Author(s):  
S. Cauchard ◽  
N. Van Reet ◽  
P. Büscher ◽  
D. Goux ◽  
J. Grötzinger ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Trypanosoma Evansi ◽  
Host Defense Peptides ◽  
Content Type ◽  
Sytox Green ◽  
Highly Active ◽  
Transmission Electron ◽  
Mitochondrial Alteration ◽  
Plasma Membrane Permeabilization

ABSTRACTTrypanozoonparasites infect both humans, causing sleeping sickness, and animals, causing nagana, surra, and dourine. Control of nagana and surra depends to a great extent on chemotherapy. However, drug resistance to several of the front-line drugs is rising. Furthermore, there is no official treatment for dourine. Therefore, there is an urgent need to develop antiparasitic agents with novel modes of action. Host defense peptides have recently gained attention as promising candidates. We have previously reported that one such peptide, the equine antimicrobial peptide eCATH1, is highly active against equine Gram-positive and Gram-negative bacteria, without cytotoxicity against mammalian cells at bacteriolytic concentrations. In the present study, we show that eCATH1 exhibits anin vitro50% inhibitory concentration (IC50) of 9.5 μM againstTrypanosoma brucei brucei,Trypanosoma evansi, andTrypanosoma equiperdum. Its trypanocidal mechanism involves plasma membrane permeabilization and mitochondrial alteration based on the following data: (i) eCATH1 induces the rapid influx of the vital dye SYTOX Green; (ii) it rapidly disrupts mitochondrial membrane potential, as revealed by immunofluorescence microscopy using the fluorescent dye rhodamine 123; (iii) it severely damages the membrane and intracellular structures of the parasites as early as 15 min after exposure at 9.5 μM and 5 min after exposure at higher concentrations (19 μM), as evidenced by scanning and transmission electron microscopy. We also demonstrate that administration of eCATH1 at a dose of 10 mg/kg toT. equiperdum-infected mice delays mortality. Taken together, our findings suggest that eCATH1 is an interesting template for the development of novel therapeutic agents in the treatment of trypanosome infections.

scholarly journals Role of Complement Receptors in Uptake ofMycobacterium avium by Macrophages In Vivo: Evidence from Studies Using CD18-Deficient Mice

1999 ◽  
Vol 67 (9) ◽  
pp. 4912-4916 ◽  
Author(s):  
Luiz E. Bermudez ◽  
Joseph Goodman ◽  
Mary Petrofsky
Keyword(s):  
Mouse Strains ◽  
Histopathological Study ◽  
Intracellular Pathogen ◽  
Complement Receptors ◽  
Transmission Electron ◽  
Granulomatous Lesions ◽  
Deficient Mice

ABSTRACT Mycobacterium avium is an intracellular pathogen that has been shown to invade macrophages by using complement receptors in vitro, but mycobacteria released from one cell can enter a second macrophage by using receptors different from complement receptors. Infection of CD18 (β2 integrin) knockout mice and the C57 BL/6 control mice led to comparable levels of tissue infection at 1 day, 2 days, 1 week, and 3 weeks following administration of bacteria. A histopathological study revealed similar granulomatous lesions in the two mouse strains, with comparable numbers of organisms. In addition, transmission electron microscopy of spleen tissues from both strains of mice showed bacteria inside macrophages. Our in vivo findings support the hypothesis that M. avium in the host is likely to use receptors other than CR3 and CR4 receptors to enter macrophages with increased efficiency.

scholarly journals Use of RNA Arbitrarily Primed-PCR Fingerprinting To Identify Vibrio cholerae Genes Differentially Expressed in the Host following Infection

2000 ◽  
Vol 68 (7) ◽  
pp. 3878-3887 ◽  
Author(s):  
Amit Chakrabortty ◽  
Soumita Das ◽  
Sabita Majumdar ◽  
Kanchan Mukhopadhyay ◽  
Susanta Roychoudhury ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Vibrio Cholerae ◽  
Transmission Electron Microscope ◽  
Differentially Expressed ◽  
Loop Model ◽  
Pcr Fingerprinting ◽  
Transmission Electron ◽  
Ultrathin Sections

ABSTRACT Evidence suggests that a repertoire of Vibrio cholerae genes are differentially expressed in vivo, and regulation of virulence factors in vivo may follow a different pathway. Our work was aimed at characterization of in vivo-grown bacteria and identification of genes that are differentially expressed following infection by RNA arbitrarily primed (RAP)-PCR fingerprinting. The ligated rabbit ileal loop model was used. The motility of in vivo-grown bacteria increased by 350% over that of in vitro-grown bacteria. Also, the in vivo-grown cells were more resistant to killing by human serum. By using the RAP-PCR strategy, five differentially expressed transcripts were identified. Two in vitro-induced transcripts encoded polypeptides for the leucine tRNA synthatase and the 50S ribosomal protein, and the three in vivo-induced transcripts encoded the SucA and MurE proteins and a polypeptide of unknown function. MurE is a protein involved in the peptidoglycan biosynthetic pathway. The lytic profiles of in vivo- and in vitro-grown cells suspended in distilled water were compared; the former was found to be slightly less sensitive to lysis. Ultrathin sections of both cells observed under the transmission electron microscope revealed that in contrast to the usual wavy discontinuous membrane structure of the in vitro-grown cells, in vivo-grown cells had a more rigid, clearly visible double-layered structure. The V. cholerae murE gene was cloned and sequenced. The sequence contained an open reading frame of 1,488 nucleotides with its own ribosome-binding site. A plasmid containing the murE gene of V. cholerae was transformed into V. cholerae 569B, and a transformed strain, 569BME, containing the plasmid was obtained. Ultrathin sections of 569BME viewed under a transmission electron microscope revealed a slightly more rigid cell wall than that of wild-type 569B. When V. cholerae 569B and 569BME cells were injected separately into ligated rabbit ileal loops, the transformed cells had a preference for growth in the ileal loops versus laboratory conditions.

scholarly journals In Vitro Killing of Candida albicans by Fatty Acids and Monoglycerides

2001 ◽  
Vol 45 (11) ◽  
pp. 3209-3212 ◽  
Author(s):  
Gudmundur Bergsson ◽  
Jóhann Arnfinnsson ◽  
Ólafur Steingrı́msson ◽  
Halldor Thormar
Keyword(s):  
Electron Microscopy ◽  
Fatty Acids ◽  
Transmission Electron Microscopy ◽  
Candida Albicans ◽  
Fatty Acid ◽  
Saturated Fatty Acid ◽  
Capric Acid ◽  
Transmission Electron ◽  
Ultrathin Sections

ABSTRACT The susceptibility of Candida albicans to several fatty acids and their 1-monoglycerides was tested with a short inactivation time, and ultrathin sections were studied by transmission electron microscopy (TEM) after treatment with capric acid. The results show that capric acid, a 10-carbon saturated fatty acid, causes the fastest and most effective killing of all three strains of C. albicans tested, leaving the cytoplasm disorganized and shrunken because of a disrupted or disintegrated plasma membrane. Lauric acid, a 12-carbon saturated fatty acid, was the most active at lower concentrations and after a longer incubation time.

scholarly journals Evaluation of a semi-automated in vitro feeding system for Dermacentor reticulatus and Ixodes ricinus adults

2018 ◽  
Vol 117 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Bettina Böhme ◽  
Christoph Krull ◽  
Peter-Henning Clausen ◽  
Ard M. Nijhof
Keyword(s):  
Ixodes Ricinus ◽  
Dermacentor Reticulatus ◽  
Feeding System ◽  
In Vitro Feeding

scholarly journals Scanning force microscopy of microtubules and polymorphic tubulin assemblies in air and in liquid

1995 ◽  
Vol 108 (3) ◽  
pp. 1063-1069
Author(s):  
W. Vater ◽  
W. Fritzsche ◽  
A. Schaper ◽  
K.J. Bohm ◽  
E. Unger ◽  
...  
Keyword(s):  
Scanning Force Microscopy ◽  
Force Microscopy ◽  
A Value ◽  
Transmission Electron ◽  
Associated Proteins ◽  
Scanning Force ◽  
Fibrous Morphology ◽  
Ultrathin Sections ◽  
20 Nm

We have investigated microtubules (MTs) and polymorphic assemblies, formed in vitro from isolated microtubule protein, by scanning force microscopy (SFM) in air and in liquid. Immobilization of MTs was achieved by placing a drop of the assembly solution on a polylysine-coated coverslip. After washing with taxol and air drying, the characteristic microtubular fibrous morphology appeared in the SFM. The MTs formed a network similar to that obtained by transmission electron microscopy (TEM). A height of approximately 9.5 nm for dried MTs was computed from the surface topography. Glutaraldehyde fixation of the MTs yielded higher structures (approximately 14 nm), which swelled to approximately 20 nm after rehydration, a value close to the MT diameter of approximately 25 nm determined from TEM images of ultrathin sections. The protofilament pattern of the MTs and surface attached MT-associated proteins were not apparent from SFM, although the height along the long axis of the MTs appeared slightly modulated. In addition to MTs, various polymorphic tubulin assemblies including ribbons, hoops and double-walled MTs were visualized by SFM.

scholarly journals Effect of platelet-activating factor (PAF) on stallion sperm motility, capacitation and the acrosome reaction

Reproduction ◽  
2003 ◽  
pp. 605-613 ◽  
Author(s):  
AI Odeh ◽  
JJ Dascanio ◽  
T Caceci ◽  
J Bowen ◽  
LA Eng
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Statistical Analysis ◽  
Platelet Activation ◽  
Mammalian Cells ◽  
Acrosome Reaction ◽  
Platelet Activating Factor ◽  
Biological Properties ◽  
Transmission Electron

Phospholipids are an essential component of all mammalian cells; platelet activating factor (PAF=1-O-alkyl-acetyl-sn-glycero-3-phosphocholine) is a signalling phospholipid that has many biological properties in addition to platelet activation. PAF receptors have been detected on stallion spermatozoa; therefore, the aim of this study was to evaluate the effect of synthetic PAF on the motility, capacitation and the acrosome reaction of stallion spermatozoa. Treatment of ten stallion semen samples with 10(-4)-10(-13) mol PAF l(-1) resulted in significant differences in motility and capacitation (r(2)=0.81 and 0.83, respectively). Statistical analysis indicated that PAF also has an effect on acrosome reaction (r(2)=0.20). PAF concentrations, incubation time and their interaction had a highly significant (P<0.01) effect on motility. After capacitation in vitro with PAF, and induction of the acrosome reaction by progesterone, transmission electron microscopy was conducted on the spermatozoa of three stallions to detect the true acrosome reaction. Differences in PAF concentrations were highly significant (r(2) for intact: 97.2; reacted: 89.8; and vesiculated: 98.1). The results indicate that a lower concentration of PAF enhances motility and induces capacitation of stallion spermatozoa, whereas a higher concentration of PAF induces the acrosome reaction.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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