Morphological and Molecular Identification of Spirometra Tapeworms (Cestoda: Diphyllobothriidae) from Carnivorous Mammals in the Serengeti and Selous Ecosystems of Tanzania

Spirometra tapeworms (Cestoda: Diphyllobothriidae) collected from carnivorous mammals in Tanzania were identified by the DNA sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 (cox1) and internal transcribed spacer 1 (ITS1), and by morphological characteristics. A total of 15 adult worms were collected from stool samples and carcasses of Panthera leo, Panthera pardus, and Crocuta crocuta in the Serengeti and Selous ecosystems of Tanzania. Three Spirometra species: S. theileri, S. ranarum and S. erinaceieuropaei were identified based on morphological features. Partial cox1 sequences (400 bp) of 10 specimens were revealed. Eight specimens showed 99.5% similarity with Spirometra theileri ({"type":"entrez-nucleotide","attrs":{"text":"MK955901","term_id":"1796114604","term_text":"MK955901"}}MK955901), 1 specimen showed 99.5% similarity with the Korean S. erinaceieuropaei and 1 specimen had 99.5% similarity with Myanmar S. ranarum. Sequence homology estimates for the ITS1 region of S. theileri were 89.8% with S. erinaceieuropaei, 82.5% with S. decipiens, and 78.3% with S. ranarum; and 94.4% homology was observed between S. decipiens and S. ranarum. Phylogenetic analyses were performed with 4 species of Spirometra and 2 species of Dibothriocephalus (=Diphyllobothrium). By both ML and BI methods, cox1 and ITS1 gave well supported, congruent trees topology of S. erinaceieuropaei and S. theileri with S. decipiens and S. ranarum forming a clade. The Dibothriocephalus species were sisters of each other and collectively forming successive outgroups. Our findings confirmed that 3 Spirometra species (S. theileri, S. ranarum, and S. erinaceieuropaei) are distributed in the Serengeti and Selous ecosystems of Tanzania.     

The evaluation of contrast-enhancing brain lesions: pitfalls in current practice

The definitive diagnosis of space-occupying brain lesions can be established more readily since the advent of computerized tomographic (CT) scanning. Some brain lesions are more clearly defined when contrast-enhancing agents are utilized; however, so-called ring-enhancing lesions are not pathognomonic for specific neurological entities. Review of the literature suggests that at least four disorders must be considered in the differential diagnosis of contrast-enhancing lesions. These include mature brain abscesses of any etiology, cerebrovascular accidents, and primary or metastatic brain tumors. Since the medical and surgical management of these conditions is quite different, it is critical to establish a diagnosis before therapy is instituted. In many instances the combination of history, physical examination, laboratory, and radiologic examination will enable physicians to correctly diagnose the etiology of such brain lesions. However, we present two cases for which the above clinical and non-invasive parameters led to incorrect working diagnoses. Brain biopsy was required before appropriate management was eventually instituted. Potentially, such delays in diagnosis and institution of therapy can result in unnecessary morbidity and mortality. Each case illustrates the need to substantiate a presumptive diagnosis based on these clinical and radiographic criteria, regardless of how "typical" lesions may appear on CT scans.     

Anaerobic bacteria detected in inflammatory conditions of the respiratory tract

In this study a participation of anaerobic bacteria in respiratory tract diseases is presented. Bronchial washings collected by ++fibrobronchoscope constituted material for the study. Immediately after collection the material was plated onto two media for aerobic bacteria (hemomedium) and anaerobic bacteria (anaeromedium). Then, the samples were centrifuged and a sediment was plated on solid media suitable for aerobic and anaerobic bacteria. Bacterial anaerobic isolates were identified by using API 20E and their sensitivity to antibiotics was tested. From the material described above the most frequently isolated anaerobic bacteria were such as: Streptococcus intermedius, Bacteroides melaninogenicus, Veilonella sp. Among aerobic bacteria the most frequently isolated were Gram-negative rods, Streptococcus faecalis, Branhamella catarrhalis. It is worth to underline that in about 25% of cases anaerobic bacteria were the only isolates.     

Role of Staphylococcus saprophyticus in human infection.

Biological properties of Staphylococcus saprophyticus strains isolated from urinary tract infection and respiratory tract secretions were investigated. The majority of S. saprophyticus strains exhibit moderate surface hydrophobic properties, as measured by Hydrophobic Interaction Chromatography. There was no significant difference between two groups of isolates in respect to electrostatic charge. It was found that the ability to form a diffuse type of growth is characteristic for most of S. saprophyticus strains despite of source of isolation. Five carbohydrates on the surface of 25% of S. saprophyticus strains were shown by means of specific lectin agglutination. Some of the tested strains were capable to bind labelled fibrinogen.     

The mlo resistance alleles to powdery mildew infection in barley trigger a developmentally controlled defence mimic phenotype

Recessive mlo resistance alleles of the Mlo locus in barley control a non race-specific resistance response to infection by the obligate biotrophic fungus Erysiphe graminis f.sp. hordei. All the mlo alleles analysed stop fungal growth at the same developmental stage within a subcellularly restricted, highly localized cell wall apposition directly beneath the site of abortive fungal penetration. We report that near-isogenic lines carrying the alleles mlo ₁, mlo ₃ or mlo ₅ undergo dramatic spontaneous formation of cell wall appositions, not only in the absence of the fungal pathogen but also in sterile grown plants. A comparative study of spontaneous and infection-triggered cell wall appositions reveals a high degree of similarity with respect to structure, chemical composition and distinct localization within plant tissue. We show that the rate of spontaneous apposition formation is dependent on the genetic background of the plant and that its onset is under developmental control. Furthermore, spontaneous formation of wall appositions is specifically triggered by mlo alleles, since it is unaffected in the presence of the race-specific resistance allele Mlg. We propose a model for the function of the Mlo locus that suggests that both Mlo and mlo alleles control qualitatively the same apposition-based resistance mechanism, which, in the presence of the wild-type Mlo allele, is merely less efficient to provide protection against the currently common races of E. graminis f.sp. hordei.     

Structural and functional relationships of human DNA polymerases

A continuing theme of our laboraory, has been the understanding of human DNA polymerases at the structural level. We have purified DNA polymerases delta, epsilon and alpha from human placenta. Monoclonal antibodies to these polymerases were isolated and used as tools to study their immunochemical relationships. These studies have shown that while DNA polymerases delta, epsilon and alpha are discrete protiens, they must share common structural features by virtue of the ability of several of our monoclonal antibodies to exhibit cross-reactivity. A second approach we have taken is the molecular cloning of human DNA polymerase delta and epsilon. We have cloned the DNA polymerase delta cDNA, and this has allowed us to compare its primary structure to those of human polymerase alpha and other members of this polymerase family. Multiple sequence alignments have revealed that human DNA polymerase delta is also closely related to the herpes virus family of DNA polymerases. In situ hybridization has shown that the human DNA polymerase delta gene is localized to chromosome 19 q13.3–q13.4. In order to further determine the functional regions of the DNA polymerase δ structure we are currently expressing human pol δ inE. coli and baculovirus systems. Other work in our laboratory is directed toward examining the expression of DNA polymerase δ during the cell cycle.     

Explaining Differences in Repatriation Experiences: The Discovery of Coupled and Decoupled Systems

We report the results of a four-year, multiphase study on the overseas assignment at General Motors Corporation (GM). Our objective is to explain variation in the repatriation experiences of International Service Personnel (ISPs). While our principal focus is the documentation of an inductive discovery process facilitated through interviews with a wide variety of GM employees, we also present a preliminary test of an explanatory hypothesis. The hypothesis states that variation in repatriation experiences is related directly to variation in the structure and ideology of organizational units that send and receive ISPs. Units with direct linkages between GM's domestic and overseas operations (coupled systems) are associated with a pro-international ideology and positive ISP repatriation experiences. Units with no administrative or operational linkages between the domestic and overseas arenas (decoupled systems) are associated with an anti-international ideology and negative ISP repatriation experiences. Our findings suggest that the structural and ideological properties of organizational units affect both repatriation from overseas assignments and ISP career paths.     

Characterization of prostaglandin production in tissue culture of rat renal medullary cells

Renal medullary cells from the rat were used to establish a cell culture line. The morphologic characteristics of these cells were similar to renal medullary interstitial cells. They produced substantial amounts of PGE when provided with arachidonic acid or fetal calf serum. PGE production was inhibited 80–90% by indomethacin or meclofenamate. PGE release by the cells was sensitive to and stimulated by changing the culture media. Stable levels of PGE in the media could be achieved if media changes were avoided during the experimental period.