Molecular epidemiology of cryptosporidiosis: An update

Molecular tools have been developed to detect and differentiate Cryptosporidium at the species/genotype and subtype levels. These tools have been increasingly used in characterizing the transmission of Cryptosporidium spp. in humans and animals. Results of these molecular epidemiologic studies have led to better appreciation of the public health importance of Cryptosporidium species/genotypes in various animals and improved understanding of infection sources in humans. Geographic, seasonal and socioeconomic differences in the distribution of Cryptosporidium spp. in humans have been identified, and have been attributed to differences in infection sources and transmission routes. The transmission of C. parvum in humans is mostly anthroponotic in developing countries, with zoonotic infections play an important role in developed countries. Species of Cryptosporidium and subtype families of C. hominis have been shown to induce different clinical manifestations and have different potential to cause outbreaks. The wide use of a new generation of genotyping and subtyping tools in well designed epidemiologic studies should lead to a more in-depth understanding of the epidemiology of cryptosporidiosis in humans and animals.     

Alkaloids of some Mexican Zanthoxylum species

Two new 4-quinazolone alkaloids have been isolated from seed husks of Zanthoxylum arborescens. Based on their spectroscopic properties they have been assigned structures, 1-methyl-3-(2′-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2′-(4″-methoxyphenyl)ethyl]-1H,3H-quinazoline-2,4-dione. These structural assignments have been confirmed by synthesis. Skimmianine has been obtained from leaf extracts of Z. dimoncillo and Z. caribaeum while skimmianine and scopeletin have been isolated from leaf extracts of Z. fagara.     

Pseudomonas aeruginosa and Achromobacter sp.: nitrifying aerobic denitrifiers have a plasmid encoding for denitrifying functional genes

In the present work, novel heterotrophic nitrifying and aerobic denitrifying bacteria have been isolated from greenwater system of coastal aquaculture. Based on the 16S rRNA gene, FAME analysis and biochemical test, the isolates have been identified as Pseudomonas aeruginosa and Achromobacter sp. These have been named as P. aeruginosa strain DBT1BNH3 and Achromobacter sp. strain DBTN3. Denitrifying functional genes such as nitrite reductase (nirS), nitric oxide reductase (qnorB) and nitrous oxide reductase (nosZ) genes have been identified. These strains found to have a 27 kb plasmid coding for nirS and nosZ. The possibility of horizontal transfer of plasmid among Pseudomonadaceae and Alcaligenaceae families in coastal aquaculture has been explored. Further, we have studied combined nitrification and oxygen tolerant denitrification potential in the same isolates.     

Comparative scanning electron microscope (SEM) study of miracidia of four human schistosome species

The miracidia of four human blood flukes, Schistosoma haematobium, S. intercalatum, S. mansoni and S. japonicum, have been studied by means of the scanning electron microscope (SEM). Differences have been observed in their respective dimensions, in the configuration of their terebratoria (apical papillae), in the shape of the epidermal plates, and in the distribution of the sensory receptors. The most evident differences have been noticed on the terebratoria where two main patterns of organization of the anastomosing membrane foldings have been described: (1) a ‘rosette’ pattern observed in S. haematobium and S. intercalatum and (2) a ‘honeycomb’ pattern in S. mansoni and S. japonicum. The structure and the taxonomic importance of these morphological features are analysed.     

Foliar appendages in certain species ofSalvia (studies inLamiaceae VI)

Foliar appendages of eight species ofSalvia L. have been studied. Eleven types of non glandular and five types of glandular appendages have been observed. They have been classified under three major categories: (1) glandular capitate; (2) non glandular filiform and (3) non glandular capitate. Five new types of trichomes have been reported fromLamiaceae for the first time. On the basis of trichome types different species ofSalvia can be identified. A tentative key has been presented.     

Diterpenoids from sideritis pusilla subsp. flavovirens

Several new 14-hydroxybeyerene acetates have been isolated from the aerial parts of Sideritis pusilla subsp. flavovirens. In addition, an ent-kaur-15-ene (siderol) and a new ent-7α, 18-dihydroxybeyer-15-ene (flavovirol) have been obtained from the same source. The structures of these new acetates have been established by chemical and spectroscopic means and the structure of flavovirol has been confirmed by ¹³C NMR.     

Transmission of sex cells of one species through the body of a second species in the genus Xenopus. II. Interspecific matings

Hybrids between X. mulleri and X. laevis have been prepared by two methods. By one method the hybridization has been effected either by a natural coupling following hormonal stimulation or by means of an artificial fertilization. By the other method, the primordial germ cells of mulleri have been introduced into laevis at the neurula stage and, when the host laevis had reached sexual maturity, the mulleri gametes produced have been brought into contact with laevis gametes through a natural coupling.     

N-Formylcytisine: A new alkaloid from Thermopsis chinensis

A new base have been isolated from Thermopsis chinensis along with N-methylcytisine, cytisine, anagyrine and lupanine. The new alkaloid have been shown to be N-formylcytisine.     

Structure of asclepin and some observations on the NMR spectra of Calotropis glycosides

Asclepin has been shown to be 3′-O-acetylcalotropin using various chemical and physical methods. The NMR data of all the Calotropis glycosides have been analysed in conjunction with that of asclepin, certain anomalies have been pointed out and revised structures have been proposed for the acetylated glycosides.     

Bacteriolytic enzymes from the blood plasma of the sheep

Bacteriolytic factors from the blood plasma of healthy sheep have been studied. Three enzymes not described earlier in the literature have been identified and characterized. Two enzymes exhibit activity toward Escherichia coli and have molecular weights of 15 ± 2 kDa. The third enzyme that exhibits activity toward E. coli and Micrococcus luteus has a molecular weight of 34 ± 4 kDa. The kinetic parameters of bacterial lysis for all enzymes have been determined; in particular, optimal pH values for each of the substrates used have been found. For the identification of the enzymes, trypsinolysis and a mass-spectroscopic study of fragments have been carried out. The results were compared with the data on sheep proteins available in the Swiss-Prot, NCBI, and MSDB databases.     

Exotic flagellates of coastal North Sea waters

Flagellate species have been shown to survive transocean passage by ballast water and the large dinoflagellateGymnodinium catenatum was introduced from Japanese to Tasmanian waters in this way.Gymnodinium mikimotoi—better known asGyrodinium aureolum—andFibrocapsa japonica as well asAlexandrium leeii are good candidates to have been introduced recently. Species which seem to have been introduced recently into the North Sea but apparently are transported from adjacent seas by currents into the region areGymnodinium chlorophorum andAlexandrium minutum. Species reported as introduced due to misidentifications areGymnodinium catenatum andLepidodinium viride. Under other names the speciesProrocentrum minimum, Prorocentrum redfieldii, andHeterosigma akashiwo have been known for a long time in the North Sea. The recent reports of threeChattonella species may be either due to introduction or they have been overlooked. The reasons why the introduction of flagellates into coastal North Sea waters is difficult to prove will be discussed.     

Reactions of chitosan: 4. Preparation of organosoluble derivatives of chitosan

Fully subtituted di-O-acetyl-N-acetylchitosan (chitin diacetate) has been prepared by a route in which the hydroxyl groups are acetylated prior to N-acetylation. This overcomes the previously reported intramolecular steric hindrance to esterification caused by the N-acetamido group. The resultant products were of high viscosity but had a limited solubility range. Di-O-acrylcarbamate derivatives of N-acetylchitosan (chitin) have been produced by a similar route, whilst di-O-arylcarbamate-N-arylureidochitosans have been prepared directly from chitosan. These products also have limited solubility ranges and have inherent viscosities similar to that of di-O-acetylchitosan prepared from the same batch of chitosan.     

The influence of temperature on the binding of AMP to phosphorylase b

Equilibrium dialysis measurements have been performed at several temperatures, ranging from 5 to 30°C, to calculate the binding constants of AMP to phosphorylase b (EC 2.4.1.1). ΔH = ?10 kcal/mol and ΔS = ?6.4 e.u. have been obtained for the binding process. Measurements of enzymatic activity have been performed in the same temperature range. An activation energy of 16 kcal has been calculated for the enzyme-catalysed reaction. Absorption difference spectra induced by AMP in phosphorylace b when AMP is bound to its high affinity site have also been carried out at these temperatures. The equilibrium constant for the binding of AMP to phosphorylase b, the enzyme activity as well as the molar absorption coefficient of the absorption difference spectra studied show no discontinuity with temperature from 5 to 30°C.     

A developmental analysis of the histone patterns of two species of Xenopus and their hybrids

The histone patterns in Xenopus laevis and X. borealis have been examined at various developmental stages using acid-urea polyacrylamide electrophoresis. Qualitative differences between the two species have been demonstrated in the H1 fraction. These differences are not affected by alkaline phosphatase digestion. Quantitative changes during development in both H1 and H4 fractions have also been observed. In addition, histones from hybrids of the two species have been examined. H1 histones characteristic of both species are present by the neurula stage in laevis ♀ × borealis ♂ hybrids. Quantitative changes observed in borealis development are mimicked in laevis ♀ × borealis ♂ hybrid development.     

A study of the complexes of borate ions and some cyclitols using 11B-n.m.r. spectroscopy

Complexes between borate ion and cyclohexane-cis-1,2-diol, cyclohexane-cis,cis-1,3,5-triol, and myo- and epi-inositol have been investigated by ¹¹B-n.m.r. spectroscopy. Three different complexes of myo-inositol have been identified. Formation constants have been determined for the borate complexes of each cyclitol. Where the complex is formed from the less-stable chair conformer, MNDO calculations have been performed to determine the enthalpies of inversion. For myo-inositol, an iterative method of calculation gave a set of constants which provided a good match with experimental data and supported the proposed formulation of its borate complexes.     

Minor indole alkaloids of Alstonia macrophylla

Three indole alkaloids have been isolated from Alstonia macrophylla Wall. Two of these have been identified as affinisine (I) and picrinine (II). The third, a new base designated picralstonine, has been shown to possess structure (III).     

The proteins of nonoccluded Autographa californica nuclear polyhedrosis virus produced in an established cell line of Spodoptera frugiperda

Nonoccluded virions have been isolated from the extracellular fluid of cultured Spodoptera frugiperda cells that have been infected with Autographa californica nuclear polyhedrosis virus. By sucrose density gradient centrifugation, infectious virus particles have been obtained that exhibit densities of about 1.19 g/cm³. Using staining and autoradiographic techniques, about 35 polypeptides, including some high molecular weight proteins, have been detected by analysis of the virion proteins on sodium dodecyl sulfate-polyacrylamide slab gels (SDS-PAGE). Two major proteins of MW 65,000 and 42,000 have been found.     

Investigation of toxic Alternaria metabolites potentially present in UK-produced foods

Literature on the occurrence and toxicology of Alternaria mycotoxins shows that a wide range of Alternaria metabolites have been described although relatively few have been fully characterised. It has been reported that about half of the wild-type Alternaria cultures tested are highly toxic to mammals or birds but the compounds responsible have rarely been identified. Very little information is available on the nature or incidence of Alternaria mycotoxins in commodities grown in the UK. Preliminary results of an investigation of UK foods demonstrate the presence of several cytotoxic compounds in an ethyl acetate extract from an A. alternata culture. A toxic fraction has been isolated which appears to contain a compound not previously identified as an Alternaria mycotoxin.