scholarly journals Sharing of Prey: Coinfection of a Bacterium by a Virus and a Prokaryotic Predator

mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Huan Chen ◽  
Henry N. Williams
Keyword(s):  
Vibrio Vulnificus ◽  
Electron Microscopic Examination ◽  
Dual Infection ◽  
New Paradigm ◽  
Electron Microscopic ◽  
Prey Cell ◽  
Bacterial Populations ◽  
Short Supply ◽  
Content Type ◽  
Predatory Prokaryotes

ABSTRACTRarely, if ever, has a single bacterial cell been confirmed to simultaneously host two fundamentally different predators. Two such predators are viruses and the predatory prokaryotes known asBdellovibrioand like organisms. Viruses or bacteriophage are particles requiring prey cells in an active metabolic state to complete their life cycle. TheBdellovibrioand like organisms, unlike viruses, are bacteria that can efficiently infect and grow in prey which are in stationary phase. In this study, electron microscopic examination revealed an unprecedented coinfection by the two agents ofVibrio vulnificus, introducing a new bacterial predation paradigm. Rather than the viruses andBdellovibrioand like organisms competing for a single prey cell, both can survive in the same cell and successfully reproduce themselves. This is an especially valuable mechanism when the prey is in short supply, and the survival of the predators may be at stake.IMPORTANCEThis article describes the coinfection of a prokaryotic prey or host cell by both a bacteriophage (phage) and the predatory bacterium of the groupBdellovibrioand like organisms (BALOs). Such coinfection has not been previously reported and therefore introduces a new paradigm for predation of bacteria. This finding invites new studies on the interactions of BALOs, phage, and prey in predation. Predation is an important mechanism in nature for helping to keep bacterial populations in check and also plays a major role in the cycling of nutrients through the microbial loop. How dual infection by phage and BALOs imposes on these and other functions of predation is fertile ground for future studies and serves as a keystone reference on bacterial predation and mortality.

Progression of partial experimental injury to peripheral nerve

1975 ◽  
Vol 42 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Alan R. Hudson ◽  
David G. Kline
Keyword(s):  
Recovery Of Function ◽  
Electron Microscopic Examination ◽  
Ground Substance ◽  
Electron Microscopic ◽  
Early Recovery ◽  
Content Type ◽  
Proximal Stimulus ◽  
Late Recovery ◽  
Fine Print ◽  
Experimental Injury

✓ Biopsies from partially lacerated nerves were taken at the sites of proximal stimulus, laceration, and distal recording, and from stimuli and recording sites of control nerves. Electron microscopic examination of the partially lacerated major fasciculus revealed three zones of injury. The laceration zone showed neurotemetic changes, the adjacent or intermediate zone, partial degeneration, and the zone most peripheral to the laceration, changes in ground substance. Progression of the original injury is apparently due to ongoing changes in the intermediate and peripheral zones while much of the relative early recovery is due to reversal of changes in these zones. Regeneration through the laceration or neurotemetic zone is limited but does account for a small amount of late recovery of function.

Ultrastructural morphology of the olfactory pathway for cerebrospinal fluid drainage in the rabbit

1986 ◽  
Vol 64 (3) ◽  
pp. 466-473 ◽  
Author(s):  
Stephanie S. Erlich ◽  
J. Gordon McComb ◽  
Shigeyo Hyman ◽  
Martin H. Weiss
Keyword(s):  
Cerebrospinal Fluid ◽  
Connective Tissue ◽  
Electron Microscopic Examination ◽  
Olfactory Pathway ◽  
Electron Microscopic ◽  
En Bloc ◽  
Major Pathway ◽  
Content Type ◽  
Csf Drainage ◽  
Fine Print

✓ Previous physiological studies indicate that the olfactory region serves as a major pathway for cerebrospinal fluid (CSF) drainage into the lymphatic system. The present study was undertaken to determine the ultrastructural characteristics of this egress route. New Zealand White rabbits received a single bolus injection of the tracer ferritin (MW 400,000) into both lateral ventricles in such a manner as not to raise the intraventricular pressure above the normal level. The animals were sacrificed via intracardiac perfusion of fixative between less than 12 minutes and 4 hours following injection. The cribriform region was removed en bloc, decalcified, sectioned coronally, and prepared for light and electron microscopic examination. The arachnoid, dura, and periosteum surrounding the fila olfactoria passing through the cribriform plate merge together and form the perineurium, which consists of multiple layers of loosely overlapping cells with widely separated junctions and few vesicles. The perineurium surrounding the olfactory filaments at the superficial submucosal level is only one cell thick. The subarachnoid space freely communicates with the perineural space surrounding each filament. No morphological barrier between the perineural space and the loose submucosal connective tissue was identified. Whether or not the perineurium was multi- or singlelayered, ferritin was noted in abundance between the loosely overlapping perineural cells and in the submucosal connective tissue. The distribution of ferritin at 12 minutes was similar to that at 4 hours; however, the quantity of ferritin was increased at 4 hours. These results indicate that no significant barrier to CSF drainage is present at the rabbit cribriform region and that CSF reaches the submucosal region rapidly via open pathways.

Multiple supratentorial hemangioblastomas

1971 ◽  
Vol 35 (4) ◽  
pp. 396-405 ◽  
Author(s):  
Shakuntla Ishwar ◽  
Raymond M. Taniguchi ◽  
F. Stephen Vogel
Keyword(s):  
Secretory Granules ◽  
Electron Microscopic Examination ◽  
Extramedullary Hematopoiesis ◽  
Electron Microscopic ◽  
Content Type ◽  
Parietal Area ◽  
Erythropoietin Production ◽  
Well Differentiated ◽  
The Right ◽  
Mass Lesions

✓ Multiple hemangioblastomas were found above the tentorium in a 62-year-old woman who first had a discrete 2.5 cm tumor removed from the superior aspect of the tentorium adjacent to the falx, and 2 years later developed two more intracranial mass lesions, one in the right parietal area, the other attached to the dura of the right frontal fossa. Histological examination of all three tumors showed precisely the same well-differentiated morphology of hemangioblastoma. Foci of extramedullary hematopoiesis were present within them. Electron microscopic examination of the last two lesions disclosed secretory granules within the tumor cells, indicative of erythropoietin production, as described previously in a hemangioblastoma. Collagen and endothelial cells were not present in quantities consistent with an angioblastic meningioma. The genesis of hemangioblastomas is discussed.

scholarly journals A Linear Plasmid-Like Prophage of Actinomyces odontolyticus Promotes Biofilm Assembly

2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Mengyu Shen ◽  
Yuhui Yang ◽  
Wei Shen ◽  
Lujia Cen ◽  
Jeffrey S. McLean ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Human Microbiome ◽  
Genomic Analysis ◽  
Electron Microscopic Examination ◽  
Oral Microbiome ◽  
Extracellular Dna ◽  
Linear Plasmid ◽  
Electron Microscopic ◽  
Content Type ◽  
Human Oral Cavity

ABSTRACT The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not well understood. Recently, we isolated Actinomyces odontolyticus subsp. actinosynbacter strain XH001 from the human oral cavity, and genomic analysis revealed the presence of an intact prophage named xhp1. Here, we demonstrated that xhp1 is a linear plasmid-like prophage, which is a newly identified phage of A. odontolyticus. The prophage xhp1 genome is a 35-kb linear double-stranded DNA with 10-bp single-stranded, 3’ cohesive ends. xhp1 exists extrachromosomally, with an estimated copy number of 5. Annotation of xhp1 revealed 54 open reading frames, while phylogenetic analysis suggests that it has limited similarity with other phages. xhp1 phage particles can be induced by mitomycin C and belong to the Siphoviridae family, according to transmission electron microscopic examination. The released xhp1 particles can reinfect the xhp1-cured XH001 strain and result in tiny blurry plaques. Moreover, xhp1 promotes XH001 biofilm formation through spontaneous induction and the release of host extracellular DNA (eDNA). In conclusion, we identified a linear plasmid-like prophage of A. odontolyticus, which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity. IMPORTANCE The biology of phages as members of the human oral microbiome is understudied. Here, we report the characterization of xhp1, a novel linear plasmid-like prophage identified from a human oral isolate, Actinomyces odontolyticus subsp. actinosynbacter strain XH001. xhp1 can be induced and reinfect xhp1-cured XH001. The spontaneous induction of xhp1 leads to the lysis of a subpopulation of bacterial hosts and the release of eDNA that promotes biofilm assembly, thus potentially contributing to the persistence of A. odontolyticus within the oral cavity.

scholarly journals YMC-2011, a Temperate Phage of Streptococcus salivarius 57.I

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Wen-Chun Chou ◽  
Szu-Chuan Huang ◽  
Cheng-Hsun Chiu ◽  
Yi-Ywan M. Chen
Keyword(s):  
Mitomycin C ◽  
Electron Microscopic Examination ◽  
Streptococcus Thermophilus ◽  
Hypothetical Protein ◽  
Open Reading Frames ◽  
Ecological Niches ◽  
Streptococcus Salivarius ◽  
Electron Microscopic ◽  
Content Type ◽  
Genes Encoding

ABSTRACT Streptococcus salivarius is an abundant isolate of the oral cavity. The genome of S. salivarius 57.I consists of a 2-Mb chromosome and a 40,758-bp circular molecule, designated YMC-2011. Annotation of YMC-2011 revealed 55 open reading frames, most of them associated with phage production, although plaque formation is not observed in S. salivarius 57.I after lytic induction using mitomycin C. Results from Southern hybridization and quantitative real-time PCR confirmed that YMC-2011 exists extrachromosomally, with an estimated copy number of 3 to 4. Phage particles were isolated from the supernatant of mitomycin C-treated S. salivarius 57.I cultures, and transmission electron microscopic examination indicated that YMC-2011 belongs to the Siphoviridae family. Phylogenetic analysis suggests that phage YMC-2011 and the cos-type phages of Streptococcus thermophilus originated from a common ancestor. An extended −10 element (p L ) and a σ70-like promoter (p R ) were mapped 5′ to Ssal_phage00013 (encoding a CI-like repressor) and Ssal_phage00014 (encoding a hypothetical protein), respectively, using 5′ rapid amplification of cDNA ends, indicating that YMC-2011 transcribes at least two mRNAs in opposite orientations. Studies using promoter-chloramphenicol acetyltransferase reporter gene fusions revealed that p R , but not p L , was sensitive to mitomycin C induction, suggesting that the switch from lysogenic growth to lytic growth was controlled mainly by the activity of these two promoters. In conclusion, a lysogenic state is maintained in S. salivarius 57.I, presumably by the repression of genes encoding proteins for lytic growth. IMPORTANCE The movement of mobile genetic elements such as bacteriophages and the establishment of lysogens may have profound effects on the balance of microbial ecology where lysogenic bacteria reside. The discovery of phage YMC-2011 from Streptococcus salivarius 57.I suggests that YMC-2011 and Streptococcus thermophilus-infecting phages share an ancestor. Although S. salivarius and S. thermophilus are close phylogenetically, S. salivarius is a natural inhabitant of the human mouth, whereas S. thermophilus is commonly found in the mammary mucosa of bovine species. Thus, the identification of YMC-2011 suggests that horizontal gene transfer via phage infection could take place between species from different ecological niches.

Morphological study of clinically nonsecreting pituitary adenomas in patients under 40 years of age

1991 ◽  
Vol 75 (6) ◽  
pp. 902-905 ◽  
Author(s):  
Shozo Yamada ◽  
Kalman Kovacs ◽  
Eva Horvath ◽  
Tadashi Aiba
Keyword(s):  
Microscopic Examination ◽  
Pituitary Adenomas ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Null Cell ◽  
Younger Patients ◽  
Content Type ◽  
Morphological Studies ◽  
Null Cell Adenomas ◽  
Fine Print

✓ Clinically nonsecreting pituitary adenomas removed at surgery from 69 patients under 40 years of age were studied by histological, immunocytochemical, and transmission electron microscopic examination. By morphological analysis. 19 tumors were found to be null-cell adenomas. 17 silent gonadotroph adenomas, 14 silent subtype 3 adenomas of unknown cellular origin, 13 silent subtype 1 or subtype 2 corticotroph adenomas, three oncocytomas, and three silent thyrotroph adenomas. These results indicate that the incidence of null-cell adenomas and oncocytomas, which are known to be the most common types of nonsecreting pituitary adenomas in patients over 40 years of age, is relatively low in younger patients. This trend is even more obvious in patients younger than 30 years of age. It can be concluded that clinically nonsecreting pituitary adenomas represent a heterogeneous group morphologically, and that the incidence of the different tumor types varies depending on the patient's age. These findings underline the importance of careful morphological studies. It is proposed that, in order for the correct morphological diagnosis to be made, tumors removed surgically from patients with clinically nonsecreting pituitary adenomas (especially younger patients) should be investigated not only by histological means but also by immunocytochemical and electron microscopic examination. The information obtained from such analysis may be useful in assessing prognosis and deciding on the appropriate treatment.

Hypothalamic hamartoma

1989 ◽  
Vol 70 (4) ◽  
pp. 640-645 ◽  
Author(s):  
Shunji Nishio ◽  
Shigeru Fujiwara ◽  
Yasutaka Aiko ◽  
Iwao Takeshita ◽  
Masashi Fukui
Keyword(s):  
Clinical Symptoms ◽  
Morphological Characteristics ◽  
Epileptic Seizures ◽  
Electron Microscopic Examination ◽  
Pathological Examination ◽  
Hypothalamic Hamartoma ◽  
Neurofilament Protein ◽  
Electron Microscopic ◽  
Content Type ◽  
Neuronal Processes

✓ Two cases of hypothalamic hamartoma are presented. The first patient was a 4-year-old boy with precocious puberty, and the second was a 6-year-old boy with epileptic seizures. In both patients, clinical symptoms and signs appeared at the age of 2 years and progressed thereafter. Computerized tomography and magnetic resonance imaging in both cases disclosed a suprasellar mass lesion in continuity with the hypothalamus. Removal of the lesions affected the endocrinological status and/or seizure control. Pathological examination revealed the lesions to be composed of well-differentiated neuronal and glial cells. Immunohistochemical study demonstrated the presence of beta-endorphin, corticotropin-releasing factor, oxytocin, and neurofilament protein (210 kD) in the neuronal cells of the first patient, but no neuropeptides were detected in the second. Electron microscopic examination on the second patient disclosed the presence of many nonmyelinated and some myelinated neuronal processes containing dense-core and clear vesicles. The morphological characteristics and the role of surgery for this lesion are discussed.

Cerebral arterial constriction after experimental subarachnoid hemorrhage is associated with blood components within the arterial wall

1983 ◽  
Vol 58 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Theodore M. Liszczak ◽  
Vassilios G. Varsos ◽  
Peter McL. Black ◽  
J. Philip Kistler ◽  
Nicholas T. Zervas
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Structural Changes ◽  
Arterial Wall ◽  
Autologous Blood ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Content Type ◽  
Arterial Lumen ◽  
Angiographic Vasospasm ◽  
Basilar Arteries

✓ Sequential cisternal blood injections in dogs reproduce some of the morphological and physiological features seen in man after subarachnoid hemorrhage-induced vasospasm. This study reports the morphological features observed in cerebral vessels in areas exposed to subarachnoid blood. Subarachnoid hemorrhage was produced in dogs by two cisternal injections of non-heparinized autologous blood 48 hours apart. Dogs were sacrificed 48 hours after the second injection. Angiographic narrowing of the basilar artery was routinely present 48 hours after the second injection, and there was a good correlation between angiographic vasospasm and a narrowed arterial lumen at postmortem examination. All basilar arteries showed structural changes with electron microscopic examination; these included endothelial cell vacuoles, early smooth-muscle cell necrosis, intimal changes, and adventitial erythrocytes, leukocytes, and mast cells. The finding that accompanied vessel constriction most uniformly was packing of the adventitial cerebrospinal fluid spaces with erythrocytes. Angiographically visible spasm was resistant to vasodilators. These data suggest that infiltration of blood elements into the arterial wall is an important concomitant feature of morphological and angiographic vasospasm.

Prepontine epithelium-lined cyst

1981 ◽  
Vol 55 (2) ◽  
pp. 312-317 ◽  
Author(s):  
Osamu Hirai ◽  
Junichiro Kawamura ◽  
Taro Fukumitsu
Keyword(s):  
Periodic Acid ◽  
Correct Diagnosis ◽  
Electron Microscopic Examination ◽  
Neurological Deficits ◽  
Epithelial Cyst ◽  
Electron Microscopic ◽  
Periodic Acid Schiff ◽  
Content Type ◽  
Intracranial Cysts ◽  
Visual Disturbances

✓ A 30-year-old woman presented with recurrent episodes of severe headache associated with visual disturbances. Neurological examination showed minimal neurological deficits. Angiography, computerized tomography, and radioisotope cisternography revealed a large cyst in the prepontine region, which did not communicate with either the subarachnoid space or the ventricular system. Histologically, the cyst was lined by columnar and/or cuboidal cells, which contained materials positive on periodic acid-Schiff staining. Ultrastructurally, there were two types of cells, ciliated and nonciliated. Characteristic findings were continuous basement membrane, microvilli covered with electron-dense material, several intercellular junctional devices, and an open intercellular space which was occasionally filled with a migrating cell. These findings would support the view that the epithelial cyst with such features was derived from endodermal tissue rather than from neuroepithelium. Electron microscopic examination is indispensable in making a correct diagnosis of intracranial cysts.

Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

1978 ◽  
Vol 36 (2) ◽  
pp. 46-47
Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder
Keyword(s):  
Mammary Gland ◽  
Protein Denaturation ◽  
Chemical Constituents ◽  
Freeze Substitution ◽  
Electron Microscopic Examination ◽  
Mouse Mammary Gland ◽  
Electron Microscopic ◽  
Preparation Methods ◽  
Microscopic Studies ◽  
Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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