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1.
DeMar Taylor James S. Phillips Daniel E. Sonenshine Frank E. Hanson 《Experimental & applied acarology》1991,12(3-4):275-296
Neutering of part-fed females eliminated copulatory behavior inDermacentor variabilis (Say) andD. andersoni Stiles males. Extracts from the anterior reproductive tracts of part-fed (7 days) females partly restored the male copulatory behavior in conspecific neutered females. Similar extracts from unfed females did not restore the behavior, suggesting that the pheromone was produced during feeding. Perception of the genital sex pheromone by sensillae on the male cheliceral digits was confirmed by electrophysiological techniques.Males ofD. variabilis andD. andersoni responsed positively to authentic ecdysone and 20-hydroxyccdysone (20HE) in neutered female bioassays. Responses to sterols were significantly lower than to ecdysteroids. Electrophysiological assays suggest a sensitivity of males to high doses of ecdysteroids. The strongest responses were to 20HE in both species. Ecdysteroids, specifically ecdysone and 20HE were shown to be present in the anterior reproductive tracts in excess of amounts that could be explained by mere hemolymph contamination. Ecdysteroids were also found in washings of the vaginal lumen of these two species.Dermacentor andersoni females contained larger amounts of ecdysteroids thanD. variabilis females. 20-hydroxyecdysone and possibly ecdysone appear to be components of the genital sex pheromone ofD. variabilis andD. andersoni. Species recognition may be facilitated by these components, but the complete mechanism is not yet fully understood.Supported by grant AI10, 986 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health and Human Services, Bethesda, Maryland. 相似文献
2.
N. Biswal A. K. Kleinschmidt H. C. Spatz T. A. Trautner 《Molecular & general genetics : MGG》1967,100(1):39-55
Summary The following properties of the DNA of B. subtilis phage SP50 were established: Molecular weight (in Daltons) 102×106 (sedimentation velocity) 97×106 (viscosity) 97×106 (contour lengths of electron micrographs) Base Composition (in % GC) 41.7 (chemical analysis) 44 (melting point) 44 (buoyant density) No unusual bases were observed. The complementary strands of the DNA can be separated. The phage DNA has genuine single strand breaks. The number and distribution of such breaks appears to be determined by the host on which phages were grown.This investigation was supported in part by a Public Health Service research grant GM 13,666 from the National Institutes of General Medical Sciences, AI 01267 from the National Institutes of Allergy and Infectious Diseases, AM 04763 from the National Institutes of Arthritis and Metabolic Diseases; cancer research funds from the University of California; and a grant from the Hartford Foundation. 相似文献
3.
Summary Synapses were found in rat cerebellar and brainstem cultures with the electron microscope. Three distinct types of synaptic terminals were described. The similarity between synapses found in vitro and in vivo was emphasized.Supported by USPHS Grants 5 Tl 459-04 and NB 03114-03S1 from the National Institutes of Health, Bethesda, Maryland.The authors wish to express their sincere appreciation to Mrs. Eleanor Morris for her assistance in preparing the cultures and Mr. Earl Pitsinger for his photographic assistance. 相似文献
4.
Initiation and characterization of a diploid cell line from larval tissues ofAedes dorsalis (Meigen)
Barbara E. Cahoon James L. Hardy William C. Reeves 《In vitro cellular & developmental biology. Plant》1978,14(3):255-260
Summary Mosquito cell cultures were initiated from the minced tissues of newly hatchedAedes dorsalis (Meigen) larvae. Continuous cell division occurred only after an adaptive period of approximately 6 months. Optimal growth
of the cells required a relatively low pH of 6.5. Karyological studies showed that the cells have remained diploid (2n=6)
for 60 serial passages and that the cultures are free of contaminating cells. The cultures also were shown to be free of bacteria
(includingMycoplasma), fungi and virions. Subpopulations (strains) of the original parental cultures have been selected and characterized on the
basis of morphology, karyology, growth rate and monolayer formation.
These studies were supported in part by funds from the Office of Naval Research, by Research Grant AI03028 from the National
Institute of Allergy and Infectious Diseases, and by General Research Support Grant I-SO1-FR-05441 from the National Institutes
of Health, U.S. Department of Health, Education and Welfare. 相似文献
5.
Barron EL Sosnovtsev SV Bok K Prikhodko V Sandoval-Jaime C Rhodes CR Hasenkrug K Carmody AB Ward JM Perdue K Green KY 《PloS one》2011,6(6):e21435
Antibody prevalence studies in laboratory mice indicate that murine norovirus (MNV) infections are common, but the natural history of these viruses has not been fully established. This study examined the extent of genetic diversity of murine noroviruses isolated from healthy laboratory mice housed in multiple animal facilities within a single, large research institute- the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (NIAID-NIH) in Bethesda, Maryland, U.S. Ten distinct murine norovirus strains were isolated from various tissues and feces of asymptomatic wild type sentinel mice as well as asymptomatic immunodeficient (RAG 2(-/-)) mice. The NIH MNV isolates showed little cytopathic effect in permissive RAW264.7 cells in early passages, but all isolates examined could be adapted to efficient growth in cell culture by serial passage. The viruses, although closely related in genome sequence, were distinguishable from each other according to facility location, likely due to the introduction of new viruses into each facility from separate sources or vendors at different times. Our study indicates that the murine noroviruses are widespread in these animal facilities, despite rigorous guidelines for animal care and maintenance. 相似文献
6.
James SL 《Trends in parasitology》2001,17(9):405-406
The tenth annual meeting of the National Institute of Allergy and Infectious Diseases Internal Centers for Tropical Disease Research was held, 7-9 May 2001, in Bethesda, MD, USA. 相似文献
7.
The National Institutes of Allergy and Infectious Diseases and International Centers for Tropical Disease Research Network held their 11th annual meeting ‘Research Beyond Boundaries’ on 15–18 April 2002. 相似文献
8.
Blood-brain barrier alterations in bacterial meningitis: Development of an in vitro model and observations on the effects of lipopolysaccharide 总被引:3,自引:0,他引:3
Allan R. Tunkel Susan W. Rosser Eric J. Hansen W. Michael Scheld 《In vitro cellular & developmental biology. Animal》1991,27(2):113-120
Summary To further examine the effects of purifiedHaemophilus influenzae type b lipopolysaccharide (LPS) on blood-brain barrier permeability, we have developed an in vitro model of the BBB. Microvascular
endothelial cells were isolated from rat cerebral cortices by enzymatic digestion, dextran centrifugation, and separation
on percoll gradients. The cells were determined to be endothelial in origin by positive fluorescent staining for Factor VIII-related
antigen and the ability to take up acetylated low density lipoproteins, and their cerebral origin by the formation of junctional
complexes in vitro. Cells were seeded onto semipermeable polycarbonate filters and permeability assessed by measuring traversal
of radioactive albumin across the monolayer. Treatment of the cells with LPS at concentrations of 1.0μg/ml and 0.1μg/ml for 4 h led to statistically significant increases in albumin permeability of 4.6% (P=0.001) and 5.6% (P<0.001), respectively, without evidence of cell death as assessed by release of lactate dehydrogenase into the media. These
results indicate that LPS significantly increases albumin permeability across a monolayer of cerebral microvascular endothelial
cells in the absence of host inflammatory cells. Future studies on the effects of LPS on intracellular regulation will determine
the mechanisms responsible for these alterations.
Supported by a research grant (RO1-AI17904) and a training grant (T32-AI07046) from the National Institute of Allergy and
Infectious Diseases, Bethesda, MD. W. Michael Scheld is an established investigator of the American Heart Association. 相似文献
9.
Summary The complement fixation test was employed to study the possible serological relationship between PPLO 4387 andCorynebacterium C4387. No cross reactions between the two organisms were demonstrated by the methods employed. The limitations of the complement
fixation test in this study were discussed. Because of these limitations and the accumulated evidence from other types of
studies, the authors concluded that the results obtained are not necessarily proof of the absence of a relationship between
the PPLO and theCorynebacterium sp.
This work was supported by a PHS Research Grant E-2332 from the National Institute of Allergy and Infectious Diseases, U.S.
Public Health Service.
This paper is part of a thesis presented to the Graduate School of the University of Maryland in partial fulfillment of the
requirements for the M.S. degree in Microbiology. Mailing address: Department of Bacteriology, Walter Reed Army Institute
of Research, Washington 12, D.C. 相似文献
10.
Michael G. Gabridge Marlene J. Bright Helen R. Richards 《In vitro cellular & developmental biology. Plant》1982,18(1):55-62
Summary Cell monolayer cultures were prepared from hamster tracheal explants by a collagenase exposure and subsequent incubation in
Waymouth’s MAB 87/3 medium. The epithelial outgrowth occurred on glass cover slips. Cilia on the monolayers continued to beat
normally after the “parent” explant was removed. Monolayer cultures infected withMycoplasma pneumoniae had significant amounts of attachment. A morphological analysis of the attachment was conducted with scanning electron microscopy.
Clusters, cocci, and filaments ofM. pneumoniae all attached to the epithelial cells, but the filaments were especially common. Mycoplasmas were seen in association with
both ciliated and nonciliated cell membranes. On ciliated cells, mycoplasmas were on the ciliary strands and on the cell membrane.
When located immediately adjacent to or in between cilia, mycoplasmas were oriented vertically with the constricted attachment
tip oriented down toward the host cell membrane. When located more than a micron away from the ciliary fibers, mycoplasmas
lay horizontally along the epithelial cell membrane. The photographic data suggest that clusters or “sperules” of mycoplasmas
may liberate individual mycoplasmas that attach to the cell membrane. It appears that the receptor sites forM. pneumoniae are rather uniformly distributed along the ciliated cell membrane, and are not restricted to the interciliary areas.
Electron microscopy was done with the cooperation of Dr. R. Macleod and the staff of the Center for Electron Microscopy at
the University of Illinois. Critical editorial review was provided by C. Dayton.
This investigation was supported in part by grants to M. G. G. from the National Institute of Allergy and Infectious Diseases
(AI 12559) and the National Heart, Lung, and Blood Institute (HL 23806), Bethesda, Maryland. 相似文献
11.
Conclusion The major accomplishment of the Workshop was probably the realization of many of its participants that most of the 21 availableH- 2 variants aretrue mutations very likely derived from single nucleotide substitutions. Any theory of the pleiotropic effect of theH- 2 genes must now take this fact into account; such theories must also consider the observation that a wide variety of immunological phenomena are affected byH- 2 mutations and thus, apparently, are controlled by a single gene.May 17–19, 1978, Woods Hole, Massachusetts. Sponsored by the U.S. National Institute of Allergy and Infectious Diseases and the National Cancer Institute. 相似文献
12.
Society News
Technology advancement for studying gene expression and gene function: a workshop reportSponsored by National Institute of Child Health and Human Development, National Institute of General Medical Sciences, National Center for Human Genome Research, National Center for Research Resources, National Institutes of Health, Bethesda, Maryland 20892, USA 相似文献13.
Rabbits were immunized with high-density lipoprotein (HDL) isolated from the serum of other rabbits by ultracentrifugation
and gel filtration. Two different precipitating antibodies were elicited which distinguished two antigenically different genetic
variants, i.e., allotypes, of HDL. The allotypes were identified as HDL based on the observation that on immunoelectrophoresis
the antigen-antibody precipitate formed by the reaction of each of the antiallotype antisera with electrophoresed rabbit serum
appeared electrophoretically in the α1 region and reacted with Sudan black and with β-naphthyl acetate. In addition, the precipitin bands formed by the reaction
of each antiallotype antiserum with a normal rabbit serum coalesced with the precipitin band formed by the reaction of goat
anti-HDL with the same normal rabbit serum. The inheritance of the two allotypes is controlled by a pair of allelic genes,
as shown by genetic studies of 312 progeny from 83 rabbit families. This HDL locus, designatedLhj, was shown not to be linked to theLpq locus of low-density lipoprotein nor to any of five other loci controlling allotypic specificities of different rabbit serum
proteins. The use of these allotypes for studying the structure and biosynthesis of HDL is discussed.
This study was supported by Research Grant PHS AI-07043 (Dr. S. Dray) and PHS AI-09241 from the National Institutes of Allergy
and Infectious Diseases. One of us (K. L. K.) is the recipient of National Institutes of Health Career Development Award (AI-28687). 相似文献
14.
The role of cobalt in amino acid antagonisms 总被引:1,自引:0,他引:1
Eugene D. Weinberg 《Antonie van Leeuwenhoek》1960,26(1):321-328
Summary The bacteriostatic action towardsStaphylococcus aureus of L-cysteine is enhanced strongly by copper and of L-and D-serine by cobalt. The serine-enhancing activity of cobalt is
completely suppressed by either L-histidine or L-cysteine. It is suggested that metal binding may play a role in some instances
of amino acid antagonism, especially when one member of the pair is either histidine or cysteine.
Supported by a research grant (E-2252) from the National Institute of Allergy and Infectious Diseases, U.S. Public Health
Service. 相似文献
15.
Protoplasts of systemic dimorphic fungal pathogens: Histoplasma capsulatum and blastomyces dermatitidis 总被引:2,自引:0,他引:2
Summary Protoplasts have been released fromH. capsulatum in the mycelial and yeast phases and from the mycelial and incompletly converted yeast phase ofB. dermatitidis by the enzymatic action of snail digestive juice. There is great variation in the mode of protoplast formation not only between species but between the two morphological forms, particularly inH. capsulatum
These studies were supported in part by grants from the American Thoracic Socicty and the United States Public Health Service National Institute of Allergy and Infectious Diseases (1-R1-AI-7520-01). 相似文献
16.
Summary Biopsies taken from cases of microsporosis caused byMicrosporon audouinii orM. canis were sectioned. Ultraviolet microscopy revealed that the fluorescent matter is located only in the cortex and medulla of the hair. Neither intrapilary hyphae nor the sheath of arthrospores surrounding the infected hair fluoresce.These investigations were supported by a grant from the John A. Hartford Foundation, Inc., New York, New York and in part, training grant No. 2A-5289 (C4), from the National Institute of Arthritis and Metabolic Diseases, U.S. Public Health Service, Bethesda, Maryland 20014. 相似文献
17.
Susan Upchurch Michael G. Gabridge 《In vitro cellular & developmental biology. Plant》1983,19(3):203-209
Summary MRC-5 human lung fibroblasts maintained in Eagle's basal medium (BME) with either 10% fetal bovine serum (FBS) or 10% newborn
bovine serum (NBS) did not respond identically to infection byMycoplasma pneumoniae. Fibroblasts grown in NBS did not develop any cytopathic effect (CPE) when infected withM. pneumoniae, whereas those maintained in FBS developed a pronounced CPE. There was also a difference in sensitivity to infection for
fibroblasts maintained in the two sera before the infection. Fibroblasts maintained in NBS, then transferred to FBS 48 h before
infection, were still less sensitive toM. pneumoniae infection than cells maintained constantly in FBS.Mycoplasma pneumoniae attached comparably to the fibroblasts grown in the two sera, so the differences in CPE development could not be attributed
to differences in mycoplasma attachment. Measurements of DNA, RNA, and protein syntheses of the fibroblasts grown in NBS and
FBS indicate that the cells in NBS were growing more rapidly than those in FBS. A determination of the doubling times shows
that the doubling time of cells in NBS was 44 h, whereas that of cells in FBS was 51 h. Polyacrylamide gel electrophoresis
of samples of NBS and FBS showed significant differences in serum protein composition. The NBS had several protein bands that
were lacking in the FBS. This study demonstrates the importance of serum effects in the study ofM. pneumoniae infection.
This work was supported in part by Public Health Service Grant AI 17795 from the National Institute of Allergy and Infectious
Diseases, Bethesda, MD. 相似文献
18.
Dianne M. Rausch Sidney B. Simpson Jr. 《In vitro cellular & developmental biology. Plant》1988,24(3):217-222
Summary The immune suppressed lizard,Anolis carolinensis, can be used to test for in vivo tumor production by cell lines derived from a variety of ectothermic vertebrates. Cell lines
tested for tumor production were also assessed for loss of attachment-dependent proliferation and contact inhibition of cell
overlap. The results demonstrate that the criteria standardly used to assess transformation and neoplastic change in cultured
mammalian cells apply equally well to cultured cells from ectotherms.
Supported by grants AG01476 and NS24162 from the National Institutes of Health, Bethesda, MD. 相似文献
19.
ABSTRACT. Sporozoites of Sarcocystis capracanis and S. tenella (Apicomplexa) penetrated all four cell types tested (bovine monocytes, BM; bovine pulmonary artery endothelial cells, CPA; Madin-Darby bovine kidney; and ovine monocytes). Sporozoites of S. tenella developed to meronts in BM and CPA; those of S. capracanis developed to meronts in BM only. Both species of Sarcocystis developed to large first-generation meronts followed by small meronts. At 40 to 50 days after inoculation (DAI) of sporozoites, considerably more merozoites of S. tenella were harvested from CPA (24.9 × 106 merozoites/75-cm2 flask; n = 4) than from BM (1.9 × 106 merozoites/75-cm2 flask; n = 4). Merozoites of S. capracanis were most numerous in BM at 88 to 100 DAI during which time 2.1 × 106 merozoites/75-cm2 flask (n = 4) were harvested. 相似文献
20.