Monohydrocalcite in calcareous corpuscles of Mesocestoides corti

Mesocestoides corti (syn. vogae), as many other cestode platyhelminthes, contains abundant mineralized structures called calcareous corpuscles. These concretions may constitute as much as 40% of the dry weight of the organisms, but their function remains poorly understood. In this work, we reviewed the mineral composition of the calcareous corpuscles of M. corti. X-ray diffraction pattern showed that the major mineral component of the corpuscles is a hydrated form of calcium carbonate, monohydrocalcite, also confirmed by infrared spectrometry. The baseline shift of the X-ray diffraction spectra suggested the presence of amorphous calcium carbonate, accordingly to previous reports, and an organic matrix was confirmed by FTIR. Monohydrocalcite is a rare mineral unusually found in biominerals. Although the significance of monohydrocalcite in biominerals has not been determined, the knowledge of corpuscles composition is of relevance to establish their function and for the elucidation of the mechanisms involved in mineralization processes.     

Mesocestoides corti: cation concentration in calcareous corpuscles of tetrathyridia grown in vitro

The tetrathyridia larval stage of the cestode Mesocestoides corti has been maintained for 5 days in vitro in the presence of Cr(III), Cu(II), Ga(III), In(III) T1(I), VO(II), Zn(II), and Zr (IV) cations. With the exception of the VO(II) culture, all tetrathyridia concentrated these cations in the calcareous corpuscles. Vanadium, as the vanadyl ion, appeared to have a toxic effect on the organisms and no vanadium was detected in these corpuscles by emission spectrographic analysis. Incorporation of the other ions has been shown by emission spectrographic analysis and, in the case of Ga, In, and T1, compounds containing these ions were identified by X-ray powder diffraction. The identification by emission spectrography of cations whose compounds were not identifiable by X-ray diffraction has led to the speculation that these ions may have been incorporated into the organic portion of the calcareous corpuscles rather than the inorganic portion.     

Immunoblot findings of calcareous corpuscles binding proteins in cyst fluid of Taenia solium metacestodes

After collecting calcareous corpuscles from plerocercoid of Spirometra mansoni (sparganum), we evaluated the antigenic values of calcareous corpuscles binding proteins obtained from the cyst fluid of Taenia solium metacestodes. Immunoblot analysis revealed that cysticercosis patient sera strongly recognized 10 and 95 kDa calcareous corpuscles binding proteins. This result demonstrated that calcareous corpuscles are bound with major secretory antigenic proteins, which is possibly involved in the secretory pathways of the 10 and 95 kDa proteins presenting in the cyst fluid of T. solium metacestodes.     

Incorporation of calcium into the soft tissues and calcareous corpuscles of larval Taenia taeniaeformis.

Larval Taenia taeniaeformis in vivo accumulates 45Ca2+ in soft tissues and calcareous corpuscles. Radioactivity was demonstrable in the corpuscles six months after a single dose of 45Ca2+ was administered to the host by means of a stomach tube. Ca2+ also was taken up by isolated larvae. Accumulation in vitro was more rapid then in vivo and was correlated with the external Ca2+ concentration. Temperature variation, oxygen availability, and metabolic inhibitors had little effect on the Ca2+ uptake, indicating that active transport of Ca2+ is unlikely in this parasite. Variations in the external Pi concentrations had no effect on Ca2+ accumulation or on its distribution. Addition of 5% CO2 increased the uptake of Ca2+ by the calcareous corpuscles under anaerobic conditions. Radioactivity from NaH14CO3 also was accumulated in soft tissues and corpuscles of T. taeniaeformis. Assuming that the 14C taken up by the corpuscles was in the form of 14CO3(2-), the ratio of Ca2+ to CO3(2-) accumulation in the corpuscles approximates the ratio of these constituents in dolomite: CaMg(CO3)2.     

A new method for concentration of proteins in the calcareous corpuscles separated from the spargana of Spirometra erinacei

Calcareous corpuscles are a characteristic structure found in larval and adult stage cestodes. These corpuscles are known to contain several protein components and to possess protein-binding activity. However, the proteins bound to calcareous corpuscles in situ have not been studied. The present study was undertaken to identify the proteins on calcareous corpuscles. Calcareous corpuscles were purified from the plerocercoids (= spargana) of Spirometra erinacei, and serially dissolved using 0.1 M sulfamic acid solution. Collected supernatants were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining. The results showed that only the fraction remaining after the 19th dissolved fraction contained proteins. A total of 20 protein molecules were detected in gel, with major bands at 56, 53, 46, 40, 35, 29, 28, 24.5, 21, 19, 16, 13, 10 and 8 kDa. In particular, the proteins corresponding to the 21 and 16 kDa bands were most abundant. Our results demonstrated for the first time the protein contents of the calcareous corpuscles of spargana. Further studies on the functions of these proteins are required.     

Morphological and phylogenetic analysis of Raillietina spp. in indigenous chickens (Gallus gallus domesticus) in Bangladesh

Raillietina spp. (Cestoda: Davaineidae), the most common cestodes in indigenous chickens, cause a substantial production loss in poultry industry in Bangladesh. Here, we estimated the prevalence, confirmed the species and determined the genetic pattern of species of Raillietina using molecular tools. We collected and examined 375 chickens randomly from household of different villages of Mymensingh sadar and Gouripur upazila, Mymensingh district and adult parasites were isolated and identified. Genomic DNA was extracted from collected parasites, amplified ITS-2 and ND-1 genes, sequenced and analyzed. Out of 375 samples, 270 (72.0%) were found positive with Raillietina species and mean worm burden was 10.46 ± 0.56. Microscopically, three species of Raillietina, such as R. cesticillus (37.9%), R. echinobothrida (41.1%) and R. tetragona (52.8%) were detected on the basis of their morphological features. The total length, length and width of scolex, sucker and rostellum were also measured. Among different factors, age, farming nature and flock size of chickens were significantly (p < 0.05) influenced Raillietina infections. For further validation, the sequences of ITS-2 gene generated in this study were matched with reference sequences of R. cesticillus, R. echinobothrida and R. tetragona and found 99.63% − 100% similarity. The phylogenetic analyses of ITS-2 and ND-1 sequences were clustered together with the reference sequences of R. cesticillus, R. echinobothrida and R. tetragona confirming microscopic identification. This is the first confirmation of species of Raillietina along with the prevalence of the species, which will be helpful for the formulation of a control strategy and provide basic information for further molecular study.     

Role of the thyroid in the involution of the mesonephric Malpighian corpuscles in the chick embryo

The mesonephros of the chick embryo normally begins to regress during the second half of embryonic life. Experimental methods, such as adenohypophysis grafting, hypophysectomy or use of antithyroid drugs, which stimulate or depress the thyroid function of the embryo, modified accordingly the regressive processes occurring in the mesonephric Malpighian corpuscles, particularly at the level of the glomerular basement laminae. These results as well as the known sensitivity of the mesonephros to thyroxine and the concordance between the steps of embryonic thyroid development and the mesonephric modifications show that the thyroid normally plays a major determining role in this phenomenon.     

Role of the spleen in Bartonella spp. infection

Bartonella spp. are intra-erythrocytic pathogens of mammals. In this study, we investigated the role of the spleen, and other tissue and organs in Bartonella infection. Using an in vivo model of mice infection by Bartonella birtlesii, we detected accumulation of bacteria in the spleen, with transient infection of the liver, but failed to detect any bacteria in brain or lymph nodes. We then compared bacteraemia in normal Balb/C mice and in splenectomized mice. Bacteraemia in splenectomized mice was 10-fold higher than in normal mice and lasted 2?weeks longer. In conclusion, the spleen seems to retain and filter infected erythrocytes rather than to be a sanctuary for chronic Bartonella infection.     

Microtubule organization in the differentiating transfer cells of the placenta inLilium spp.

Summary Placental cells in the ovarian transmitting tissue ofLilium spp. are organized as transfer cells with inbuddings facing the ovarian locule. A detailed analysis of microtubule (MT) organization during development of these polarized cells is reported here. Formation of wall projections occurs at the apical part of the cell starting on the day of anthesis, and a fully mature secretion zone is found four days after anthesis. MTs are organized into distinct cortical and central arrays. The cortical array undergoes a unique transition at anthesis. MTs in the basal half of the cell remain in longitudinal bundles while in the apical half of the cell their longitudinal orientation is replaced by a transverse alignment. One day after anthesis, these transverse bundles become a meshwork of short, randomly organized MTs, while MTs in the basal half of the cell retain their longitudinal alignment. The realignment of MTs in the apical half of the cell coincides with the deposition of the secondary cell wall. The central array is composed of short, randomly arranged strands of MTs in the cytoplasm between the nucleus and the apical and basal periclinal walls of the cell. This array first appears as solitary strands in the apical part of the cell one day before anthesis. The central array extends during development and is eventually seen in the basal half of the cell. We propose that MTs in the cortical region near the apical wall act as templates for the deposition of cellulose microfibrils in the secondary cell wall. MTs in the central array in these transfer cells may be involved in the trafficking of vesicles and/or positioning of organelles near the secretion zone.Abbreviations MT microtubule - daa day after anthesis - dba day before anthesis     

Diel organization of behaviour in milkweed bugs, Oncopeltus spp.

ABSTRACT. Daily cyclic activities in various behaviours were similar in three species of tropical Oncopeltus (Heteroptera, Lygaeidae). Opposition in females and general movement in both sexes peaked in the middle to late light period. In contrast, feeding and mating peaked at the end of the light period and the beginning of the dark respectively. Other behaviours also tended to display one or the other of these patterns. The diel timing of behaviour observed in this study essentially duplicated the periodicities of a migratory population of Oncopeltus fasciatus from Iowa. The similarity of results across species and populations suggests a general pattern for the genus which probably serves to synchronize behaviours with environmental cycles and appropriate physiology. This similarity is interesting in view of the broad geographical range of the genus across both temperate zone and tropics and in view of the differences among populations with respect to photoperiodic determination of diapause.