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.     

Arabidopsis AtcwINV3 and 6 are not invertases but are fructan exohydrolases (FEHs) with different substrate specificities

The genome of Arabidopsis thaliana contains six putative cell-wall type invertase genes (AtcwINV1-6). Heterologous expression of AtcwINV1, 3 and 6 cDNAs in Pichia pastoris revealed that the enzymes encoded by AtcwINV3 and 6 did not show invertase activity. Instead, AtcwINV3 is a 6-FEH and AtcwINV6 is a fructan exohydrolase (FEH) that can degrade both inulin and levan-type fructans. For AtcwINV6 it is proposed to use the term (6&1) FEH. In contrast, AtcwINV1 is a typical invertase. FEH activity was also detected in crude extracts of different parts of Arabidopsis. To verify that the FEH activity of AtcwINV3 and 6 were not artefacts of the heterologous expression system, the protein corresponding to AtcwINV3 was isolated from whole Arabidopsis plants and indeed showed only 6-FEH activity and no invertase activity. Although no fructans can be detected in Arabidopsis plants, it is shown that kestoses (trimers) can be synthesized in crude leaf extracts. The putative physiological significance of FEH in so-called non-fructan plants is discussed.     

Importance of pre‐anthesis anther sink strength for maintenance of grain number during reproductive stage water stress in wheat

Reproductive stage water stress leads to spikelet sterility in wheat. Whereas drought stress at anthesis affects mainly grain size, stress at the young microspore stage of pollen development is characterized by abortion of pollen development and reduction in grain number. We identified genetic variability for drought tolerance at the reproductive stage. Drought‐tolerant wheat germplasm is able to maintain carbohydrate accumulation in the reproductive organs throughout the stress treatment. Starch depletion in the ovary of drought‐sensitive wheat is reversible upon re‐watering and cross‐pollination experiments indicate that the ovary is more resilient than the anther. The effect on anthers and pollen fertility is irreversible, suggesting that pollen sterility is the main cause of grain loss during drought conditions in wheat. The difference in storage carbohydrate accumulation in drought‐sensitive and drought‐tolerant wheat is correlated with differences in sugar profiles, cell wall invertase gene expression and expression of fructan biosynthesis genes in anther and ovary (sucrose : sucrose 1‐fructosyl‐transferase, 1‐SST; sucrose : fructan 6‐fructosyl‐transferase, 6‐SFT). Our results indicate that the ability to control and maintain sink strength and carbohydrate supply to anthers may be the key to maintaining pollen fertility and grain number in wheat and this mechanism may also provide protection against other abiotic stresses.     

Inferring internal anatomy from the trilobite exoskeleton: the relationship between frontal auxiliary impressions and the digestive system

Lerosey‐Aubril, R., Hegna, T.A. & Olive, S. 2011: Inferring internal anatomy from the trilobite exoskeleton: the relationship between frontal auxiliary impressions and the digestive system. Lethaia, Vol. 44, pp. 166–184. The digestive system of trilobites is rarely preserved. As a result, many aspects of its organization remain unknown. Fortunately, the exoskeleton sometimes preserves evidence of soft‐tissue attachment sites that can be used to infer internal anatomy. Among them are the frontal auxiliary impressions (FAIs), probable soft‐tissue insertion sites located on the fronto‐median glabellar lobe of some trilobites. FAIs are herein described in the Carboniferous trilobite Phillipsia belgica Osmólska 1970 – representing the only known example of such structures in the Proetida and their youngest occurrence. A taphonomic scenario is proposed to explain their variable preservation. Although particularly common in the Phacopina, FAIs or FAI‐like structures are also found in several orders that differ greatly. Comparisons with modern analogues suggest that FAIs might represent attachment sites for extrinsic muscles associated with a differentiated crop within the foregut. A review of purported remains of the trilobite digestive system indicates that it usually consisted of a tube‐like tract flanked by a variable number of metamerically paired diverticulae. Its anterior portion is not particularly individualized, except in a few specimens that might hint at the presence of a crop. This differentiation of a crop might have constituted a secondarily evolution of the foregut in trilobites, occurring independently in different clades. Accompanied by a strengthening of associated extrinsic muscles, this modification of the foregut might explain the presence of more conspicuous muscle insertion sites on the glabella. Study of FAIs might therefore provide new data on the anatomy of the foregut in trilobites and evidence of diverse feeding habits. □Arthropoda, digestive system, ecology, muscle scars, Proetida, Trilobita.     

Maternal effects and additive genetic inheritance in the collared lemming Dicrostonyx groenlandicus

We examined patterns of inheritance of size, growth and behavioural traits of collared lemmings (Dicrostonyx groenlandicus). Work was conducted on field-caught parents from the Canadian Arctic and their lab-born progeny. We partitioned inherited variance in traits into additive genetic and maternal effects components by using a half-sib breeding experiment in which each sire was mated to two dams. We found no evidence of statistically significant amounts of additive genetic variance in any of the traits measured. However, significant maternal effects were detected for several size- and growth-related traits. Three behavioural traits involving aggression, dispersal and activity showed no statistically significant inheritance of any kind. The presence of maternal effects may have consequences for population dynamics by causing lags resulting in inappropriate phenotypes being produced under regimes of fluctuating selection pressure. We recommend that maternal effects should be investigated as a potential general cause of population cycles in small mammals.     

Primers for amplifying the hypervariable,male‐transmitted COII‐COI junction region in amblemine freshwater mussels (Bivalvia: Unionoidea: Ambleminae)

Freshwater bivalves in the superfamily Unionoidea possess distinct male (M)‐ and female (F)‐transmitted mitochondrial DNA (mtDNA). The former evolves independently of and at a significantly faster rate than the latter. Thus, population genetic and phylogenetic analyses of M sequences facilitate the generation of independent estimates of genetic variation and evolutionary relationships which are often more robust than those provided by analyses of F sequences alone. However, M mtDNA's rapid substitution rate often renders polymerase chain reaction (PCR) amplification difficult with ‘universal’ primers. Herein, we report on three pairs of PCR primers that consistently amplify the hypervariable M COII‐COI gene junction region in 25 bivalve genera (Unionoidea: Ambleminae).     

Revision of Pseudocorinna Simon and a new related genus (Araneae: Corinnidae): two more examples of spider templates with a large range of complexity in the genitalia

The genus Pseudocorinna Simon, 1910 is revised. The type species Pseudocorinna rutila Simon, 1910 from Guinea‐Bissau and Pseudocorinna septemaculeata Simon, 1910 from Bioko are redescribed. No material could be found of Pseudocorinna gracilior Simon, 1910 from Bioko which is to be considered nomen dubium. The genus further contains 27 species which are described as new: Pseudocorinna alligator, Pseudocorinna amicorum, Pseudocorinna amphibia, Pseudocorinna banco, Pseudocorinna bilobata, Pseudocorinna brianeno, Pseudocorinna celisi, Pseudocorinna christae, Pseudocorinna cymarum, Pseudocorinna doutreleponti, Pseudocorinna eruca, Pseudocorinna evertsi, Pseudocorinna febe, Pseudocorinna felix, Pseudocorinna gevaertsi, Pseudocorinna incisa, Pseudocorinna juakalyi, Pseudocorinna lanius, Pseudocorinna lobelia, Pseudocorinna natalis, Pseudocorinna naufraga, Pseudocorinna okupe, Pseudocorinna orientalis, Pseudocorinna perplexa, Pseudocorinna personata, Pseudocorinna ubicki, and Pseudocorinna victoria. The genus is characterized by the wide carapace and sternum and the dense network of dark warts on all sclerites of the prosoma. These structures are apparently outlets of underlying glands producing a gel‐like substance. The genus is restricted to the West and Central African forest area, ranging from Guinea‐Bissau to the eastern Democratic Republic of Congo. The species are mainly found in very wet, temporarily inundated forests. A cladistic analysis strongly supported the erection of a new, closely related genus, Crinopseudoa gen. nov. , with very similar habitus but with poorly developed warts that have kept their original hair‐socket function. This genus contains 11 species, all of which are new, and has a distribution restricted to the West‐African refuge areas around Liberia and Cameroon. The type species is Crinopseudoa bong from Liberia. It further contains Crinopseudoa billeni, Crinopseudoa bongella, Crinopseudoa caligula, Crinopseudoa catharinae, Crinopseudoa ephialtes, Crinopseudoa flomoi, Crinopseudoa leiothorax, Crinopseudoa otus, Crinopseudoa paucigranulata, and Crinopseudoa titan. Both genera can be regarded as examples of successful somatic templates with a large range of morphologically different genitalia corroborating the ‘mate check’ hypothesis. Illustrated keys to the species of both genera are provided. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 271–350.