Characterization of Encephalitozoon (Septata) intestinalis Isolates Cultured from Nasal Mucosa and Bronchoalveolar Lavage Fluids of Two AIDS Patients

ABSTRACT. Microsporidia are obligate intracellular protozoan parasites that can cause opportunistic infections in AIDS patients. Species from five genera of microsporidia are presently known to infect man. One species, Septata intestinalis originally was detected in stool specimens of individuals with chronic diarrhea and subsequently was found to disseminate to the kidneys, lungs, and nasal sinuses. This organism has since been reclassified as Encephalitozoon and in this study, we report the culture of Encephalitozoon intestinalis from a bronchoalveolar lavage specimen and a nasal mucus aspirate of two AIDS patients living in the USA. The bronchoalveolar and nasal microsporidian isolates grew in several continuous cell lines including RK-13, MDCK, HT-29, Caco-2, Vero, and 1047. Transmission electron microscopy of the clinical and cell culture specimens revealed that the new isolates appeared to be E. intestinalis based on morphology and growth of organisms in septated membrane-bound parasitophorous vacuoles. The new E. intestinalis isolates were characterized and compared with the first isolated E. intestinalis that was cultured from stool to confirm their identity and to determine if there existed any minor differences, as seen in the closely related Encephalitozoon cuniculi strains. By the methods of sodium dodecyl sulfate-polyacrylamide gel electrophoresis staining for proteins and carbohydrates, Western blot immunodetection, and polymerase chain reaction-based methods with restriction endonuclease digestion, double-stranded DNA heteroduplex mobility shift analysis, and DNA sequencing of the ribosomal DNA intergenic spacer region, the new isolates were identical to each other and to the reference isolate of E. intestinalis. In addition, with any of these methods, the E. intestinalis organisms could be distinguished from the three E. cuniculi strains, Encephalitozoon hellem, and Vittaforma corneae, which is important for diagnostics, therapeutic strategies, and epidemiology.     

Intraspecies Variability in the Esterases and Acid Phosphatases of Paramecium jenningsi and Paramecium multimicronucleatum: Assignment of Unidentified Paramecia; Comparison with the P. aurelia Complex1

ABSTRACT. Enzyme electrophoresis was exploited to identify stocks of paramecia previously not identified to particular species. Stocks collected in India and one from Panama belong to Paramecium jenningsi, while others collected in Panama or in Brazil are assignable to syngen 2 of P. multimicronucleatum on the basis of similarity of their esterase and acid phosphatase phenotypes. Inclusion of these doubled the numbers of stocks available in the two species, thereby facilitating examination of intraspecies variation and comparison of particular features of intraspecies variation found for the P. aurelia complex. Variant stocks were observed in P. jenningsi and in syngens 2, 3, and 4 of P. multimicronucleatum. In some cases the variant lacked the enzyme; in others, a change in mobility of the enzyme occurred that resulted in an electrophoretic form similar to one common in another species. Unique phenotypes were displayed by the variants of syngen 2 in P. multimicronucleatum. Hypervariability for Esterase B was observed in this syngen, where, in addition, several subtypes were seen for three other esterases. Unique phenotypes and hypervariability were also noted in P. biaurelia. Clustered variations were observed in these species and in the P. aurelia species. Unlike the situation for members of the aurelia complex, where lack of geographical differentiation between stocks in the same species is a unique feature, some such differentiation does occur in P. multimicronucleatum-2. The frequency of variant stocks in P. jenningsi was similar to that observed in the aurelia sibling species. In contrast, a significantly higher frequency of variant stocks was found in syngens 2, 3, and 4 of P. multimicronucleatum.     

Origin and Role of Collagen in the Embryo

The first collagen recognizable in the embryo is in the formof an incomplete basal lamina under the epiblast and hypoblast.We suggest that this collagen acts as a railroad track to guidethe migration of the primitive streak mesenchyme. The mesenchymeaggregates into chordamesoderm, a layer which is said to "induce"the overlying epiblast (now ectoderm) to develop into neuralfolds. This tissue interaction may be mediated by the formationof complete basal laminas separating the two tissues and bydeposition of sulfated mucopolysaccharides in the interveningextracellular space. At the very least, the collagenous basallamina serves to give the elongating cells of the developingneural tube a firm foothold. The fully formed neural tube andadjacent notochord are said to induce the sclerotome of thesomite to migrate medially and differentiate into cartilage.Notochord and neural tube basal lamina and collagen fibrilsmay play a role by guiding the migrating cells and stabilizingthe already existing chondrogenic bias of the cells. We wereunable to prove this hypothesis directly (by adding collagento somite cultures), because in our hands the somites died invitro even in the presence of neural tube and notochord. Wedid obtain direct evidence, however, that the basal lamina ofthe lens can promote the differentiation of the cornea in vitro.     

Studies on broccoli necrotic yellows virus

Electron microscopy of infected D. stramonium cells showed that the virus particles occurred in the cytoplasm. Particles were mostly bacilliform and measured 297 ± 18 times 64 ± 4 nm. In negatively stained leaf homogenates, particles were mostly disrupted; intact particles measured 267 ± 20 times 69 ± 6 nm. In brussels-sprout cells containing BNYV and CIMV, BNYV particles were rarely found compared with those of CIMV, and they occurred within and near CIMV inclusion bodies. BNYV particles were also found in extracts of virus-carrying Brevicoryne brassicae. Broccoli necrotic yellows (BNYV) and cauliflower mosaic (CIMV) viruses occurred together in naturally infected Brussels sprout plants, which showed conspicuous symptoms, and in cauliflower. BNYV was transmitted to and maintained in Datura stramonium and Hyoscyamus niger. It was partially purified from D. stramonium. Using these preparations, from which inhibitor had been removed, BNYV was manually transmitted to cauliflower, causing mild symptoms, and to Brussels sprout, causing a symptomless infection. BNYV also infected Sinapis alba but not cabbage, lettuce, Sonchus oleraceus or Plantago major. BNYV was transmitted by Brevicoryne brassicae but not by Myzus persicae, Hyperomyzus lactucae or Aleyrodes proletella.     

Opaline Silica Deposition in Rye (Secale cereale L.)

The types of opaline silica-bodies (opal phytoliths) which occurin the mature prophylls, radical and culm leaves, culms, andinflorescence bracts of rye (Secale cereale L.) are describedand figured. Silica-bodies are absent from the coleoptile, andthe adaxial epidermis of the prophylls, leaf sheaths, and inflorescencebracts. The stages of silica-body formation in young radicalleaf sheaths are also described. Alternative hypotheses forthe origin of silica-bodies are discussed.     

Decay Rates of Different mRNA in <Emphasis Type="Italic">E. coli</Emphasis> and Models of Decay

THE basis for messenger RNA instability in bacteria is not understood. Both functional capacity^1,2 and mass of messages for a given protein are lost at constant exponential rates which can differ, indicating independent processes³.     

Variability of DNA Content in Individual Cells of <Emphasis Type="Italic">Bacillus</Emphasis>

THE average content of DNA in Bacillus spores is unaffected by the growth medium and is constant for each species¹. Within the Bacillus group, however, the average amount of DNA per spore varies from species to species¹. A cell of B. cereus contains on average twice as much DNA as the spore and during sporulation this DNA is divided equally between the spore and the sporangium². Estimates^3–5 of genome size vary from 1.3 × 10⁹ to 10 × 10⁹ daltons and the number of genomes per cell from 2 to 4^4–8. Some of these variations may be associated with differences within the cells rather than differences of methodolqgy; spores within a population vary not only in size and shape, but also in their content of stainable chromatin⁹. Moreover, in ‘Renografm’ density gradients¹⁰, spores band within a range of densities. If spores are taken from a narrow part of this range, regrown and rebanded, the original pattern of dispersal occurs, suggesting that spores in the same population normally show variation in density as well as in size (A. I. Aronson, personal communication).