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1.
Cryptococcus neoformans was instilled intranasally into mice which were periodically sacrificed to determine the course of infection. Cryptococci persisted within the nasal passages throughout the 90 day study. Extranasal dissemination began 14–28 days after instillation and was still demonstrable 90 days post-exposure. Ten percent mortality was observed in mice receiving 106 cryptococci, while no mortality was observed in mice exposed to 103 or 104 cryptococci. Our research suggests that nasal colonization with C. neoformans can precede pulmonary and systemic cryptococcosis by weeks or months. 相似文献
2.
A case of cutaneous infection in a 25-year-old male caused byPaecilomyces variotii is described. Animal pathogenicity studies with normal and cortisone-treated mice revealed the predeliction ofP. variotii for skin and liver in both normal and cortisone-treated mice and for lungs and heart only in immunosuppressed mice. 5-fluorocytosine gave the best MIC value forP. variotii in vitro. This report documents for the first time thatP. variotii causes cutaneous infection. 相似文献
3.
Eulálio KD de Macedo RL Cavalcanti MA Martins LM Lazéra MS Wanke B 《Mycopathologia》2001,149(2):57-61
Natural infection of armadillos with Coccidioides immitis was studied in the state of Piauí, northeast of Brazil, endemic for coccidioidomycosis. In 1998, 26 nine-banded armadillos
(Dasypus novemcinctus) were captured in 4 different counties. The animals were sacrificed under deep anesthesia with ether. At necropsy fragments
of spleen, liver, lungs and heart were homogenized and seeded onto Sabouraud dextrose agar with and without cycloheximide
(BBL, USA). Part of each organ was also processed for histological examination. Suspected colonies of filamentous fungi observed
after the second week of incubation at room temperature, exhibiting barrel-shaped arthroconidia alternating with empty spaces,
were inoculated intraperitoneally into mice. Three armadillos proved to be infected with C. immitis. Mice inoculated with suspected colonies obtained from homogenized spleen of three and liver of two armadillos developed
disseminated coccidioidomycosis and immature and mature spherules of C. immitis were disclosed in several organs. For the first time armadillos (D. novemcinctus) were found naturally infected with C. immitis, adding new data on the ecology and on a possible role of these ancestral mammals in the evolutionary life cycle of this
fungus.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
The relationship between paracoccidioidomycosis in ddY mouse and its estrous cycle was studied. Adult ddY mice of both sexes were used as experimental animals. Estrous cycle of female mice was examined before inoculation of Paracoccidioides brasiliensis yeast cells and mice were divided into 5 groups such as proestrus, estrus, metestrus-I, metestrus-II and diestrus. Each mouse was inoculated intravenously with 106
P. brasiliensis yeast cell units and sacrificed on day 28 after inoculation. Their internal organs were cultured, and in addition, their histopathologies were studied. As a result, there was no difference in the organ cultures among the male and the female mice of 5 groups. However, histopathologically, the female groups at estrus, metestrus-I and metestrus-II were affected more severely than the male group, and the susceptibility of the female mice to the fungus was closely related to their estrous cycles.Abbreviations BHI-D
brain heart infusion agar supplemented with 1.0% of anhydrous dextrose
- PAS
periodic acid-Schiff techniques
- PBS
phosphate buffered saline solution
- SD
standard deviation 相似文献
5.
Granuloma formation in nude (nu/nu) mice and their heterozygous littermates (nu/+ mice) against Histoplasma capsulatum var. capsulatum infection was studied.A culture of H. capsulatum var. capsulatum, isolated from a granuloma in the nasal cavity of a Japanese patient, was used in this experiment. Sixteen specific-pathogen-free male nu/nu and 32 nu/+ mice were used in this study.The nu/+ mice were divided into two groups. Sixteen nu/+ mice in one group and 16 nu/nu mice were inoculated intraperitoneally with 106 yeast cells of the fungus, those in the other group of nu/+ mice were inoculated intravenously with the same number of the yeast cells. Two mice out of each group were sacrificed 2, 3, 7, 11, 14, 18, 25 and 30 days after inoculation, and each of their organs was examined histopathologically. In addition, pieces of these tissues were cultured on Sabouraud's dextrose agar slants.In the nu/+ mice inoculated intraperitoneally, although the fungus was recovered from the spleen, kidney and lymph nodes during the initial course of the infection, lesions were not detected in their histopathological sections. In the nu/+ mice inoculated intravenously, colonies were recovered from all of the organs examined, other than the brain and thymus, 7 days after inoculation.Histopathologically, a few microfoci consisting chiefly of mononuclear cells with or without yeast cells were found in the liver sections 4 days after inoculation. Seven and 11 days after inoculation the number of lesions had increased. They had large accumulations of mononuclear cells. From day 14 on, almost all of the yeast cells had lost most of their staining affinity or were destroyed in the granuloma. From day 25 on, the granulomatous lesions changed gradually to fibrous tissue.In the nu/nu mice the fungus was readily recovered from the spleen, liver, kidney and lymph nodes. Histopathologically, a few microfoci consisting of mononuclear cells were present in the liver sections 4 days after inoculation. That is to say, during the initial course of infection granulomas were formed. In the liver, from day 7 on, the lesions were large and their number increased. However, there was a definite difference between the nu/nu and nu/+ mice. In the former, the yeast cells were not killed, and they continued to multiply within the granulomas. These granulomas were never transformed into fibrous tissue. 相似文献
6.
The occurrence of Aspergillus flavus in vegetative tissue of cotton plants and its relation to seed infection 总被引:1,自引:0,他引:1
Twenty-seven mature cotton bolls with Aspergillus flavus Link colonies naturally occurring on the surface of the boll or lint were collected in the field in Arizona along with their subtending stems and peduncles. Bolls inoculated through the carpel wall 30 days after anthesis were allowed to mature in the field and were collected in the same manner. The seed and stem and peduncle sections of each boll were surface-sterilized, plated on agar media and observed for A. flavus. Seventy-eight percent of the naturally contaminated bolls with A. flavus in the seed also had the fungus in the stem and peduncle, whereas only 31% of the naturally contaminated bolls with no A. flavus in the seed had the fungus in the stem or peduncle. This difference was significant (P=0.0125), indicating a positive relationship between seed infection and stem and peduncle infection. All of the bolls inoculated through the carpel wall had A. flavus in the seed, but only 11% of the stem and peduncle sections were infected, indicating that the fungus does not readily grow downward from the boll into the supporting stem or peduncle.This unidirectional pattern of movement (upward) was further substantiated in greenhouse experiments where cotton seedlings were inoculated at the cotyledonary leaf scar with A. flavus and plants were sequentially harvested, surface sterilized and plated. Aspergillus flavus was isolated from the cotyledonary leaf scar, flower buds, developing bolls, and stem sections in the upper portion of the plant. It was never isolated from roots or stem sections below the cotyledonary node, again indicating that the fungus does not readily move downward through the plant. 相似文献
7.
Alnus incana seedlings were successfully inoculated with an endomycorrhizal fungus (Glomus fasciculatus), an ectomycorrhizal fungus (Paxillus involutus) and an isolate ofFrankia (ACN1) simultaneously. The effects of the inoculation treatments on the growth performance of the seedlings were evaluated under controlled conditions.The overall growth performance of the seedlings inoculated with the three organisms was better than those inoculated withFrankia, G. fasciculatus andP. involutus individually or withFrankia+G. fasciculatus andFrankia+P. involutus combinations. The highest growth performance and mycorrhizal infection occurred when the seedlings were inoculated simultaneously withFrankia+G. fasciculatus+P. involutus. 相似文献
8.
The fungal entomopathogen Beauveria bassiana became established as an endophyte in coffee seedlings grown in vitro and inoculated with B. bassiana suspensions in the radicle. The fungus was recovered as an endophyte 30 and 60 days postinoculation, from stems, leaves,
and roots, and at 60 days postinoculation one of the isolates was also recovered as an epiphyte. Fusarium sp., Rhodotorula sp., and four bacterial morpho-species were also detected, indicating these were present as endophytes in the seed. 相似文献
9.
Trichoderma hamatum, T. harzianum andT. koningii were isolated from wheat and rye-grass roots from a field in Western Australia. Frequency of occurrence ofTrichoderma spp. was higher on roots subjected to washing only, for both wheat and rye-grass than the roots which were surface-sterilized with 0.6% or 1.25% NaOCl.Trichoderma spp. were recovered at a higher frequency on PDA amended with lactic acid (pH 4.5) than on PDA alone (pH 5.6) or PDA with streptomycin. In general,Trichoderma spp. were isolated at a higher frequency from roots of wheat than that of rye-grass.T. hamatum occurred at a higher frequency in rye-grass roots than in wheat, whereasT. harzianum was more common in roots of wheat than in rye-grass, especially in seedling and milky ripe stages.T. koningii was recovered at a higher frequency from roots at seedling stage of rye-grass than wheat, the reverse being true at tillering stage.T. koningii was not recovered from roots of either host in any sampling when they were surface sterilized with 1.25% NaOCl.The take-all fungus was isolated from wheat and rye-grass roots more frequently at tillering and stem extension stages than others. It was severely pathogenic to both hosts in sterilized and non-sterilized soil.Addition of lactic acid, HCl or streptomycin to PDA did not affect the growth of theTrichoderma spp. tested, but the growth was slower on Martin's medium than on other media. In generalT. harzianum andT. koningii grow faster thanT. hamatum. The growth of the three species were not different at 20 and 25°C, but at 15°c growing of all species was significantly reduced.Incorporation of lactic acid into PDA prevented the bacterial growth in all treatments. Streptomycin too reduced but to a lesser degree than lactic acid. Surface sterilization with NaOCl decreased the recovery of both bacteria and fungi.
T. hamatum andT. koningii reduced the mortality of wheat and rye-grass plants inoculated with the take-all fungus in sterilized and non-sterilized soil, whereT. harzianum did not protect wheat or rye-grass from infection by the take-all fungus. 相似文献
10.
This study was conducted to explore systemic infection by the Aspergillus flavus group into corn ears via the stalk. An A. parasiticus mutant which produces norsolorinic (NOR) acid (a visible orange intermediate of the aflatoxin biosynthetic pathway) was used
in field studies to monitor systemic infection of corn stalk and ear tissues. Corn hybrids resistant and susceptible to aflatoxin
contamination were grown in the field and inoculated prior to tasseling by inserting A. parasiticus infested toothpicks into stalks between the 5th and 6th node below the lowest ear shoot. Beginning 2 weeks after inoculation,
systemic infection by the NOR mutant was assessed weekly by collecting ear shank tissue and stalk tissue from the nodes between
the infection sites and the developing ears. Ears were collected at the end of the growing season to determine the level of
kernel infection by the NOR mutant. In two separate studies, the A. parasiticus NOR mutant was isolated from stalk tissues at all of node positions and ear shank tissue from several susceptible corn hybrid
plants at the first harvest date 2 weeks after inoculation. The NOR mutant was also isolated from stalk and ear tissue of
a resistant hybrid. The NOR mutant was only isolated from kernels of susceptible hybrids in 2003 and 2004. Infection rates
of kernels in infected ears were very low (<1%). In 2005, the fungus was found in only one kernel from an ear of the resistant
hybrid. The NOR mutant was not isolated from stalks, ears, or kernels from control (uninoculated) plants grown in the plots
with inoculated plants. Although infection levels of corn kernels were low, systemic movement of the A. parasiticus up the stalk appears to be another possible route to infection of developing corn ears. 相似文献
11.
Okigbo RN 《Mycopathologia》2005,159(2):307-314
The potential of isolates of Bacillus subtilis from yam farm soil to control rot of yam in storage barns was investigated. Yam tubers inoculated in vivo with B. subtilis showed no rot while those inoculated with Aspergillus niger, Botryodiploidia theobromae or Penicillium oxalicum showed considerable rot. The set of yams in which B. subtilis and the fungi were simultaneously inoculated produced rot whereas those in which B. subtilis was inoculated a day before the fungi was inoculated were totally reduced or free of rot. Many fewer fungi were isolated from the surface of tubers treated with B. subtilis than from the untreated (control) and there was high recovery of B. subtilis (99–100%) throughout the period of storage. Rot build up was faster in uninoculated control tubers or those inoculated with a spoilage fungus, while those treated with the antagonist were totally reduced or free of rot. The culture filtrate of B. subtilis prevented spore germination in some spoilage fungi. The importance of this study in relation to farmers in developing countries is discussed. 相似文献
12.
The susceptibility of splenectomized mice to Sporothrix schenckii was studied, and the role of the spleen in the host defense is discussed.
S. schenckii Sp-1 and ddy male mice were used. The mice were divided into 3 groups consisting of splenectomized, sham-operated and intact mice. Each mouse was inoculated intravenously with 2×106 yeast cells 7 days after operation and the mice were sacrified at adequate intervals for 30 days. Then histological sections stained with H&E or by PAS were prepared from various visceral organs. Using the liver sections the number of yeast cells in a 40 mm2 was counted. Furthermore, the colony forming unit in 100 mg of the liver tissue was compared to each other.In the sham-operated and intact mice many purulent lesions appeared on the 5th day. On the 8th day mononuclear cells accumulated at the foci, and on the 10th day most of the foci became granulomatous. The number of yeast cells in granulomatous lesions reached a peak on the 10th day and thereafter decreased abruptly. On the other hand, in the splenectomized mice approximately half of foci became granulomatous on the 5th day, and the number of yeast cells in the foci began to decrease after the 5th day.There were definite differences in the colony forming unit between the splenectomized and sham-operated or intact mice sacrificed 9 days after inoculation. The colony forming unit of the former is 9.3×105 on the average, while that of the latter two is 5.6×106 and 5.1×106 on the average, respectively.In conclusion the resistance of ddy mice to S. Schenckii infection is enhanced due to splenectomy. 相似文献
13.
Leslie L. Allee Mark S. Goettel Alla Gol'berg H. S. Whitney D. W. Roberts 《Mycopathologia》1990,111(1):17-24
A study ofper os inoculated larvae was undertaken to determine if the entomopathogenic fungus,Beauveria bassiana, is able to infect the Colorado potato beetle,Leptinotarsa decemlineata, via the alimentary tract. Surface orper os inoculated larvae which were immediately surface sterilized post inoculation did not succumb to infection, whereas those larvae not sterilized became infected. Histological studies of fed or starved, agnotobiotic (with microbial flora) and axenic larvae revealed that conidia can germinate in the gut regardless of the presence of gut microflora. However, infection via the alimentary tract was never observed in fed larvae and only noted in a single starved individual. It is concluded that infections ofper os inoclated larvae occurred after surface contamination of the integument by viable conidia contained in the frass. The rate of food passage through the gut is probably important in preventingper os infections. 相似文献
14.
IL-10 is an important mediator of the enhanced susceptibility to pneumococcal pneumonia after influenza infection 总被引:6,自引:0,他引:6
van der Sluijs KF van Elden LJ Nijhuis M Schuurman R Pater JM Florquin S Goldman M Jansen HM Lutter R van der Poll T 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(12):7603-7609
Secondary pneumococcal pneumonia is a serious complication during and shortly after influenza infection. We established a mouse model to study postinfluenza pneumococcal pneumonia and evaluated the role of IL-10 in host defense against Streptococcus pneumoniae after recovery from influenza infection. C57BL/6 mice were intranasally inoculated with 10 median tissue culture infective doses of influenza A (A/PR/8/34) or PBS (control) on day 0. By day 14 mice had regained their normal body weight and had cleared influenza virus from the lungs, as determined by real-time quantitative PCR. On day 14 after viral infection, mice received 10(4) CFU of S. pneumoniae (serotype 3) intranasally. Mice recovered from influenza infection were highly susceptible to subsequent pneumococcal pneumonia, as reflected by a 100% lethality on day 3 after bacterial infection, whereas control mice showed 17% lethality on day 3 and 83% lethality on day 6 after pneumococcal infection. Furthermore, 1000-fold higher bacterial counts at 48 h after infection with S. pneumoniae and, particularly, 50-fold higher pulmonary levels of IL-10 were observed in influenza-recovered mice than in control mice. Treatment with an anti-IL-10 mAb 1 h before bacterial inoculation resulted in reduced bacterial outgrowth and markedly reduced lethality during secondary bacterial pneumonia compared with those in IgG1 control mice. In conclusion, mild self-limiting influenza A infection renders normal immunocompetent mice highly susceptible to pneumococcal pneumonia. This increased susceptibility to secondary bacterial pneumonia is at least in part caused by excessive IL-10 production and reduced neutrophil function in the lungs. 相似文献
15.
Due to the high frequency of oral mucosal lesions observed in paracoccidioidomycosis patients, it was advocated that the infection
was acquired by the traumatic implantation of the etiologic agent Paracoccidioides brasiliensis. Although at present this theory is considered invalid, it has not yet been excluded in experimental studies. In order to
determine if intra-oral inoculation could explain the pathogenesis of paracoccidioidomycosis, 64 BALB/c mice were inoculated
intra-orally with 850.000 viable P. brasiliensis conidia into the mandibular body. Animals were sacrificed at various time intervals up to 20 weeks and cultures were made
from gingiva, lungs, spleen, and liver. Additionally, histopathological studies of the mandibular body were also performed.
P. brasiliensis was isolated from all gingival tissues during the interval 24–72 h, indicating that the infection was active. During the
5–10 week period, the infection appeared to have been controlled at the inoculation site as cultures showed a significant
reduction in colony forming units (CFU); however, at the 15–20 week period such control was lost and the fungus was recovered
once more. Dissemination to other body sites was rare; thus, the lungs were involved in just one animal (2%), the liver in
two (3%) and the spleen in seven (11%).
The infection became established as proven by positive organ cultures, but the dissemination pattern did not correspond to
the one observed in humans. Based on these findings, the intra-oral traumatic route does not appear to mimic the natural history
of paracoccidioidomycosis.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
A. Desai K. Murali-Krishna B. Ramireddy V. Ravi R. Manjunath 《Journal of biosciences》1997,22(1):33-45
Japanese encephalitis virus (JEV) is a positive stranded RNA virus that belongs to the flavivirus group. JEV infection damages
the central nervous system (CNS) and is one of the main causative agents of acute encephalitis. H-2 restricted virus-specific
cytotoxic T lymphocytes (CTL) have been generated specifically against JEV in our laboratory and these CTL have been shown
to protect mice against lethal challenge with JEV. Virus replication was found to be inhibited in the brains of animals that
were adoptively transferred with JEV specific CTL as revealed by immunohistological staining as well as viral plaque assays.
We further show that virus specific CTL could be recovered from such protected mice as long as 45 days after adoptive transfer. 相似文献
17.
A Sebacinales species was recovered from a clone library made from a pooled rhizosphere sample of Nicotiana attenuata plants from 14 native populations. Axenic cultures of the related species, Piriformospora indica and Sebacina vermifera, were used to examine their effects on plant performance. Inoculation of N. attenuata seeds with either fungus species stimulated seed germination and increased growth and stalk elongation. S. vermifera inoculated plants flowered earlier, produced more flowers and matured more seed capsules than did non-inoculated plants. Jasmonate treatment during rosette-stage growth, which slows growth and elicits herbivore resistance traits, erased differences in vegetative, but not reproductive performance resulting from S. vermifera inoculation. Total nitrogen and phosphorous contents did not differ between inoculated and control plants, suggesting that the performance benefits of fungal inoculation did not result from improvements in nutritional status. Since the expression of trypsin proteinase inhibitors (TPI), defensive proteins which confer resistance to attack from Manduca sexta larvae, incur significant growth and fitness costs for the plant, we examined the effect of S. vermifera inoculation on herbivore resistance and TPI activity. After 10 days of feeding on S. vermifera-inoculated plants, larval mass was 46% higher and TPI activity was 48% lower than that on non-inoculated plants. These results suggest that Sebacina spp. may interfere with defense signaling and allow plants to increase growth rates at the expense of herbivore resistance mediated by TPIs. 相似文献
18.
Mier T Olivares-Redonda G Navarro-Barranco H Pérez-Mejía A Lorenzana M Pérez-Torres A Toriello C 《Antonie van Leeuwenhoek》2005,88(2):103-111
Paecilomyces fumosoroseus, monospore culture EH-506/3, isolated in Mexico from Bemisia tabaci whitefly was tested for acute oral intragastric pathogenicity and toxicity in CD-1 mice. Animals were inoculated by gavage with only one dose (108 conidia/animal) of viable (72 mice), heat-killed (24 mice) fungus and compared to 18 control mice. Clinical observations were done daily; mycological and histological tests were performed during necropsies at days 3, 10, 17, and 21 after the inoculation. No mice were clinically ill or died. At the end of the study, their mean weight corresponded to healthy adults. Positive fungal cultures of feces were obtained only 24 h after inoculation. Positive cultures were found in 15 out of 360 organs (liver, spleen, kidney, brain, lung) in 12 of 72 mice inoculated with viable conidia. Gross pathology exhibited splenomegaly and liver paleness in mice inoculated with viable and heat-killed fungus. Non-germinated conidia were observed in studied organs, without any pathological tissue reaction, suggesting no mycological or histopathological evidence of fungal multiplication. The fungus was able to persist, but did not cause permanent damage to the host. This study supports the non-pathogenic/toxic status of P. fumosoroseus EH-506/3 when administered intragastrically in mice. 相似文献
19.
Black yeast (MM-7) isolated from a humidifier was studied morphologically, biologically and serologically. Furthermore, its pathogenicity was compared with that of four human isolates of Exophiala dermatitidis.The MM-7 is dimorphic and its growth at 37 °C was better than that at 27 °C. Giant colonies of the MM-7 were very similar to those of the four human isolates. Microscopically, hyphae were pale brown, slender or toruloid. Cylindrical, bottle- or flaskshaped conidiogenous cells arose from the tips and sides of the hyphae. Conidiogenous foci were also seen as small projections at the lateral walls of hyphae. One to four projections were seen at the conidiogenous apices by scanning electron microscopy. Annellation could be observed clearly on them. It was also seen in all of the human isolates of E. dermatitidis used for reference. Conidia were globose to subglobose, one celled, smooth, hyaline to brown.The MM-7 utilized all carbon compounds examined except lactose, melibiose and raffinose. It split arbutin, but did not hydrolyze starch. It utilized neither potassium nitrate, nor hydrolyzed skim milk and gelatin.The GC content of the MM-7 (56.6%) was almost the same as that of Kano's isolate (58%) and titers of agglutinin of the anti-E. dermatitidis serum to the MM-7 and four isolates of the fungus were 512-fold.From these morphological, biological and serological examinations the MM-7 was identified as E. dermatitidis (Kano) de Hoog.As far as pathogenicity is concerned, the MM-7 showed the strongest pathogenicity of all. Two of the ten mice inoculated intravenously with 5×106 cells of the MM-7 died on the 6th and 7th day, and the fungus was recovered from various organs. Histopathologically, the brains were affected severely. A large number of polymorphonuclear leucocytes accumulated around short hyphae and yeast cells to form micro-abscesses. Some micro-granulomatous lesions with a few yeast cells were also observed. Seven of the surviving eight mice showed nervous symptoms. The MM-7 was recovered from the brains of the four mice sacrificed on the 30th day. Some granulomatous lesions with a few yeast cells were recognized in the tissues. 相似文献
20.
To test the effect of seed treatment with fungicides on the development of mycorrhizal fungi, bean seeds were treated with fungicide dry or vehicled in the organic solvents, ethanol or dichloromethane and then planted in soil inoculated with the mycorrhizal fungus Glomus macrocarpum and/or the plant pathogenic fungus Fusarium solani. Measurements were made at 4 day intervals, to evaluate the location and extent of colonization of either Glomus macrocarpum or Fusarium solani in the root system. Most combinations of fungicide-solvent had little effect on the extent of colonization by each fungus individually. However, when both fungi were inoculated together, symptoms of F. solani were seen only in the tips of roots which indicate that the mycorrhizal fungus was able to limit the occurrence of the pathogenic fungus. 相似文献