Synthesis of methyl 3-O-alpha-D-mannopyranosyl-alpha-D-talopyranoside and methyl 3-O-alpha-D-talopyranosyl-alpha-D-talopyranoside

Methyl 2-O-benzyl-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl)-alpha- D-mannopyranoside (4) and methyl 2-O-benzyl-3-O-alpha-D-mannopyranosyl-alpha-D-mannopyranoside (6) were prepared from a common intermediate, namely, methyl 2-O-benzyl-4,6-O-benzylidene-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D- mannopyranosyl)-alpha-D-mannopyranoside. On treatment with tert-butylchlorodiphenylsilane, in N,N-dimethylformamide in the presence of imidazole, 4 and 6 afforded methyl 2-O-benzyl-6-O-tert-butyldiphenylsilyl-3-O-(2,3,4,6-tetra-O-acetyl -alpha-D- mannopyranosyl)-alpha-D-mannopyranoside (7), and methyl 2-O-benzyl-6-O-tert-butyldiphenylsilyl-3-O-(6-O-tert- butyldiphenylsilyl-alpha-D-mannopyranosyl)-alpha-D-mannopyranoside (8), respectively. Compound 8 was converted into its 2,3-O-isopropylidene derivative (9), and oxidation of 7 and 9 with pyridinium chlorochromate, and reduction of the resulting carbonyl intermediates gave methyl 2-O-benzyl-6-O-tert-butyldiphenylsilyl-3-O-(2,3,4,6-tetra-O-acetyl -alpha-D- mannopyranosyl)-alpha-D-talopyranoside and methyl 2-O-benzyl-6-O-tert-butyldiphenylsilyl-3-O-(6-O-tert-butyldiphe nylsilyl- 2,3-O-isopropylidene-alpha-D-talopyranosyl)-alpha-D-talopyranoside , respectively. Removal of the protecting groups furnished the title disaccharides.     

Seroprevalence of Toxoplasma gondii infection in domestic pigs in Durango State, Mexico

Little is known concerning the prevalence of Toxoplasma gondii infection in pigs in Mexico. Accordingly, antibodies to T. gondii were determined in 1,074 domestic pigs in Durango, Mexico using the modified agglutination test. Two groups (A, B) of pigs were sampled: Group A pigs (n = 555) were raised in 3 geographical regions in Durango State and Group B pigs (n = 519) were from Sonora State but slaughtered in Durango City. Overall, antibodies to T. gondii were found in 136 (12.7%) of 1,074 pigs with titers of 1∶25 in 29, 1∶50 in 23, 1∶100 in 18, 1∶200 in 22, 1∶400 in 12, 1∶800 in 8, 1∶1,600 in 2, and 1∶3,200 or higher in 22. Of the pigs raised in Durango State, seroprevalence varied with age, management, and the geographic region; pigs raised in backyards in the mountainous region had a significantly higher seroprevalence (32.1%) than those raised in the valley (13.0%) and the semi-desert regions (14.0%). In Group A pigs from Durango, seroprevalence of T. gondii infection was significantly higher in pigs older than 8 mo (19.5%) than in younger pigs (10.9%). In the whole pig population (Groups A and B together), seroprevalence was higher in pigs raised in Durango (16.0%) than in those raised in Sonora (9.1%) and higher in mixed-breed pigs (15.7%) than in pure-bred pigs (10.3%). This is the first, in-depth study on the seroprevalence of T. gondii infection of pigs in Mexico and the first report on pigs from Durango State, Mexico. Results indicate that infected pork is likely an important source of T. gondii infection for humans in Durango State.     

Seropositivity and risk factors associated with Toxoplasma gondii infection in wild birds from Spain

Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n=610), Strigiformes (n=260), Ciconiiformes (n=156), Gruiformes (n=21), and other orders (n=32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1:25) were found in 282 (26.1%, IC(95%:)23.5-28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) "vulnerable" Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN "near threatened" red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour.     

Significance of charge on lysine residue of ovine luteinizing hormone on immunological and biological properties of the hormone

In order to understand the significance of positive charge of lysine residues of ovine luteinizing hormone (oLH) on immunological and biological activity, the epsilon-NH2 group(s) of ovine LH were sequentially modified with 2-iminothiolane (2IT) that preserves the positive charge of the lysine while the overall charge of the hormone remains unchanged. These studies have also been compared with the oLH modified by N-succinimidyl 3-(2 pyridyldithio) propionate (SPDP) and succinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate (LC-SPDP) that abolish positive charge of lysine residues. The modification primarily occurs in the alpha-subunit. Sequential modification led to progressive reduction in receptor binding and immunological activities. However, the steroidogenic activity was substantially retained. The immunoreactivity and receptor binding properties of 2IT modified oLH (oLH-2IT) were less affected when compared to SPDP (oLH-SPDP) or LC-SPDP (oLH-LC-SPDP) modified derivatives suggesting that increase in hydrophobic carbon chain in oLH-LC-SPDP molecule resulted in drastic inhibition in immunological and biological properties. But the steroidogenic potential of oLH-2IT, oLH-LC-SPDP or oLH-SPDP was relatively comparable. This suggests that a single -NH2 group modification with 2IT would generate the site in the hormone for conjugation to the toxin/carrier proteins that may retain better immunological and biological activity compared to that of SPDP or LC-SPDP modified oLH.     

Evidence that the glucoamylases and alpha-amylase secreted by Aspergillus niger are proteolytically processed products of a precursor enzyme

A 125-kDa starch hydrolysing enzyme of Aspergillus niger characterised by its ability to dextrinise and saccharify starch [Suresh et al. (1999) Appl. Microbiol. Biotechnol. 51, 673-675] was also found to possess activity towards raw starch. Segregation of these activities in the 71-kDa glucoamylase and a 53-kDa alpha-amylase-like enzyme supported by antibody cross-reactivity studies and the isolation of mutants based on assay screens for the secretion of particular enzyme forms revealed the 125-kDa starch hydrolysing enzyme as their precursor. N-terminal sequence analysis further revealed that the 71-kDa glucoamylase was the N-terminal product of the precursor enzyme. Immunological cross reactivity of the 53-kDa amylase with antibodies raised against the precursor enzyme but not with the 71- and 61-kDa glucoamylase antibodies suggested that this enzyme activity is represented by the C-terminal fragment of the precursor. The N-terminal sequence of the 53-kDa protein showed similarity to the reported Taka amylase of Aspergillus oryzae. Antibody cross-reactivity to a 10-kDa non-enzymic peptide and a 61-kDa glucoamylase described these proteins as products of the 71-kDa glucoamylase. Identification of only the precursor starch hydrolysing enzyme in the protein extracts of fungal protoplasts suggested proteolytic processing in the cellular periplasmic space as the cause for the secretion of multiple forms of amylases by A. niger.     

Development and ultrastructure of Besnoitia oryctofelisi tachyzoites,tissue cysts,bradyzoites, schizonts and merozoites

Development and structure of different life cycle stages of Besnoitia oryctofelisi which has a rabbit-cat life cycle was studied by light and transmission electron microscopy. For light microscopy, Besnoitia oryctofelisi-infected tissues were stained with haematoxylin-eosin, periodic acid Schiff (PAS) reagent, and immunohistochemically with rabbit anti-B. oryctofelisi polyclonal antibodies and anti-BAG-1 antibodies. In vitro and in vivo-derived tachyzoites were 5-6 microm long and they were found to divide by endodyogeny. In tachyzoites, the nucleus was often central, and micronemes were few and located anterior to the nucleus. Earliest tissue cysts were seen in gerbils starting 12 days p.i. Early tissue cysts had an outer PAS-positive cyst wall, a middle PAS-negative host cell layer, and an inner PAS-negative parasitophorous vacuolar membrane. Organisms in early tissue cysts were PAS-negative, did not stain with anti-BAG-1 antibodies, and amylopectin granules and enigmatic bodies were absent. Tissue cysts beginning 17 days p.i. contained organisms that became PAS-positive and reacted with anti-BAG-1 antibodies, indicating they were bradyzoites. Immunoreactivity with polyclonal anti-B. oryctofelisi antibodies suggested that Besnoitia species bradyzoites are encapsulated by the host cell. Bradyzoites (10 microm) were about twice the length of tachyzoites and contained enigmatic bodies characteristic of Besnoitia bradyzoites. Unlike tachyzoites and tissue cysts, schizonts were located intravascularly in the lamina propria of the small intestine of cats. Merozoites were 5-6 microm long, had few rhoptries and amylopectin granules, had numerous micronemes and had a terminal nucleus.     

Seroepidemiology of Toxoplasma gondii infection in pregnant women in rural Durango, Mexico

The epidemiology of Toxoplasma gondii infection in pregnant women in rural Mexico is largely unknown. The seroepidemiology of T. gondii infection in 439 pregnant women from 9 communities in rural Durango State, Mexico was investigated. Using commercial enzyme-linked immunoassays, sera were tested for T. gondii IgG, IgM, and avidity antibodies. Prevalences of T. gondii IgG antibodies in the communities varied from 0% to 20%. Overall, 36 (8.2%) of the 439 women had IgG T. gondii antibodies. Ten (2.3%) women had also T. gondii IgM antibodies; IgG avidity was high in all IgM-positive women, suggesting chronic infection. None of the women, however, had delivered a known T. gondii-infected child. The seroprevalence was significantly higher (P < 0.05) in women from low socio-economic conditions (14%) than in those with higher socio-economic status (6.6%). Multivariate analysis showed that T. gondii infection was associated with soil floors at home (adjusted OR = 2.89; 95% CI: 1.12-7.49). This is the first epidemiological study of T. gondii infection in pregnant women in rural Mexico.     

Development of Sarcocystis fayeri in the equine

Eight ponies and a horse were inoculated orally with sporocysts of Sarcocystis fayeri from dogs. They were examined for clinical signs of infection and killed 10, 15, 20, 25, 30, 50 (horse), 77, 101, and 156 days after inoculation (DAI). Elevated temperature was observed in three ponies 20 and 26 DAI and anemia was observed in three ponies and the horse 15 to 69 DAI. Schizonts were found in or near cells lining capillaries or arteries of the heart, brain, and kidney 10, 20, and 25 DAI. Immature cysts containing only metrocytes were first found in muscles 50 DAI. Mature intramuscular cysts containing metrocytes and zoites or zoites alone were found 77, 101, and 156 DAI and produced patent infections in dogs fed infected meat.