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.     

Colony size,density and distribution of the leaf-cutting ant,Acromyrmex octospinosus (Reich) in cultivated fields

• 1 Fields of citrus, cacao and rubber in Trinidad were surveyed to measure the number and density of nests of Acromyrmex octospinosus. The greatest density (=153 nests/ha) was in an undisturbed field of young cacao; in established crops density ranged from 3–36 nests/ha.
• 2 Mounds of new nests appeared throughout the year, but most often 4–10 months after the main nuptial flights. Nests reached maximum size, with up to 17 holes, about three years after foundation.
• 3 The ratio of workers to brood was between 5 and 9: 1 for most of the year but it increased to 27: 1 as the sexuals developed. A medium-large colony produced 200–300 queens and males/year; the largest single nest contained about 14,000 individuals.
• 4 The average intake of leaf fragments into laboratory nests was 1 fragment/6.5 individuals. It increased to 1 fragment/2.1 individuals when sexuals were present. Foragers collecting from fields of established cacao preferred flowers to leaves.
• 5 In fields with crops planted on cambered beds, nests were concentrated on the dry edges of drains in the dry season, but they were moved to drier ground in the wet season. Nests were aggregated in 13 of the 16 fields examined, the remaining three fields were exceptionally well drained.
• 6 In newly planted cacao an estimated 6—17% of plants were defoliated and destroyed. In established cacao ants collected about 3000 flowers/ha each day. Laboratory data suggest that ants could defoliate about 25 three-year old citrus trees in a year.

     

The Significance of Transpirationally Derived Nitrogen in Protein Synthesis in Fruiting Plants of Pea (Pisum sativum L.)

Feeding of ¹⁵N-nitrate, ¹⁵N(amide)-L-glutamine, or ¹⁵N-L-glutamicacid to detached shoots of pea through the transpiration streamresults in the soluble and insoluble nitrogen of stem, leaves,and fruits becoming extensively enriched with isotopic nitrogen.The time course of labelling suggests that non-reproductiveparts are the principal centres of uptake and assimilation andthat from them translocation takes place to the developing seeds. Distribution patterns for ¹⁵N in free and protein-bound aminoacids of leaf and seed indicate that each labelled source donatesnitrogen to a wide range of amino compounds, with no evidenceof consistent differences in the manner in which each is assimilated.Alanine, glutamic acid, homoserine, and -aminobutyric acid,are the main recipients of ¹⁵N in the soluble fraction of theleaves, whilst in the insoluble fraction nitrogen of the aminoacids serine, glycine, alanine, threonine, glutamic acid + glutamine,and aspartic acid + asparagine achieves high specific labelling.Amino acids of the seeds are labelled more uniformly with ¹⁵N. A complementary ¹⁴C-labelling experiment on the translocationof photosynthetically fixed carbon from leaf to seed is describedand the labelling patterns obtained for amino acids in leaf,seed, and phloem exudate are discussed in relation to thosefor ¹⁵N.     

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.     

Comparative Histophysiology of the Pancreatic Islets

The embryological origin of the islet tissue from a common entodermalanlage with the exocrine pancreas has been questioned recently.The islet tissue may be of. neural crest origin, and the ancestralislet cells may have been "taste cells in the gut." Whether the separation of exocrine and endocrine tissue in thecyclostomes is an original one or not remains an open phylogenetickey question. One or more islet hormones affect the exocrine pancreas tissue.However, the islet topography in various groups shows that intrapancreaticislet dissemination is not a general prerequisite for the normalfunction of the exocrine tissue. The D-cell is now generally recognized as the source of a thirdislet hormone. A fourth granular cell type (X-cell) may wellsecrete a fourth islet hormone. The significance of the amphiphilislet cells, found in various species, and of the "light" cellsof the cyclostomes requires further studies. The islet function in lower vertebrates is largely unknown.So far, neither the islet cytology nor the known effects ofpancreatectomy allow far-reaching conclusions. The evolutionof the islet functions may be only understood when their interactionswith the pituitary functions become clear.     

The effects of windbreaks on the blossom-visiting fauna of apple orchards and on yield

Windbreaks of coir netting were erected in apple orchards during the flowering period in 1969 and 1970 in an attempt to increase the number of insect pollinators present. Suction traps were used to sample flying insects; insects visiting trees were sampled by examination of flowers. The sheltered zone behind the windbreaks contained more of most species of insects than elsewhere. Increases in final fruit set of approximately 30% in 1969 (cv. Cox's Orange Pippin) and 20 % in 1970 (cv. White Jersey) occurred in trees receiving maximum shelter, and these were due mainly to the increased abundance, and possibly increased activity, of honey bees there. Fruit size was not reduced where yields were increased.