A review of recent immunochemical studies ofBlomia tropicalis andEuroglyphus maynei allergens

Exposure to mites other thanDermatophagoides spp., particularlyBlomia tropicalis andEuroglyphus maynei, has been increasingly recognized as a cause of asthma. Positive skin tests and serum IgE antibodies toB. tropicalis have been reported in asthmatic patients from several areas of the world, including São Paulo (Brazil), Hong Kong and Tampa (Florida, USA). Analysis ofB. tropicalis extracts showed undetectable levels of the major Group I and Group IIDermatophagoides spp. allergens. Immunoabsorption experiments showed that most of the IgE antibodies toB. tropicalis ( 70%) reacted with species-specific allergens. Murine monoclonal antibodies toB. tropicalis could present antigens that were recognized by human IgG antibodies. Sensitization toE. maynei has been reported in Europe, North and South America and Australia. Analysis of four differentE. maynei extracts by ELISA and RIA showed thatE. maynei produces an allergen that is antigenically related toDermatophagoides Group I allergens. The amino acid sequence of this allergen (Eur m I) has recently been reported. Further identification and purification ofB. tropicalis andE. maynei allergens is required to develop specific assays for measuring these allergens in dust samples. This will make it possible to investigate the relationship between exposure toB. tropicalis orE. maynei and the development of sensitization and allergic disease.     

Isorenin, pseudorenin, cathepsin D and renin. A comparative enzymatic study of angiotensin-forming enzymes

1. Renin was purified 30 000-fold from rat kidneys by chromatography on DEAE-cellulose and SP-Sephadex, and by affinity chromatography on pepstatinyl-Sepharose. 2. The enzymatic properties of isorenin from rat brain, pseudorenin from hog spleen, cathepsin D from bovine spleen, and renin from rat kidneys were compared: Isorenin, pseudorenin and cathepsin D generate angiotensin from tetradecapeptide renin substrate with pH optima around 4.9, renin at 6.0. With sheep angiotensinogen as substrate, isorenin, pseudorenin and cathepsin D have similar pH profiles (pH optima at 3.9 and 5.5), in contrast to renin (pH optimum at 6.8). 3. The angiotensin-formation from tetradecapeptide by isorenin, pseudorenin and cathepsin D was inhibited by albumin, alpha-and beta-globulins. These 3 enzymes have acid protease activity at pH 3.2 with hemoglobin as the substrate. Renin is not inhibited by proteins and has no acid protease activity. 4. Renin generates angiotensin I from various angiotensinogens at least 100 000 times faster than isorenin, pseudorenin or cathepsin D, and 3000 000 times faster than isorenin when compared at pH 7.2 with rat angiotensinogen as substrate. 5. The 3 'non-renin' enzymes exhibit a high sensitivity to inhibition by pepstatin (Ki less than 5.10(-10) M), in contrast to renin (Ki approximately 6-10(-7) M), at pH 5.5. 6. It is concluded from the data that isorenin from rat brain and pseudorenin from hog spleen are closely related to, or identical with cathepsin D.     

A comparative study of airborne pollen concentrations of three allergenic types

Airborne concentrations of pollen from Betula (birch), Poaceae (grasses) and Artemisia (mugwort) are compared during a seven year period (90–96) with respect to both quantitative and seasonal aspects, at three different sampling sites, one in Estonia (Tartu) and two in Sweden (Stockholm and Roma on the island of Gotland). All three taxa occur in the region and are well‐known causes of allergic sensitisation. The annual total and peak values of birch, grass and mugwort pollen were found to be much higher in Tartu than in Stockholm and Roma. Both the birch and the grass pollen seasons ended later in Stockholm than in Roma and Tartu. The mugwort flowering season always began earlier in Stockholm than at the other sites, and more days elapsed between start day and peak day in Stockholm than in Tartu.     

Major house dust mite allergens Dermatophagoides pteronyssinus 1 and Dermatophagoides farinae 1 degrade and inactivate lung surfactant proteins A and D

Lung surfactant proteins (SP) A and D are calcium-dependent carbohydrate-binding proteins. In addition to playing multiple roles in innate immune defense such as bacterial aggregation and modulation of leukocyte function, SP-A and SP-D have also been implicated in the allergic response. They interact with a wide range of inhaled allergens, competing with their binding to cell-sequestered IgE resulting in inhibition of mast cell degranulation, and exogenous administration of SP-A and SP-D diminishes allergic hypersensitivity in vivo. House dust mite allergens are a major cause of allergic asthma in the western world, and here we confirm the interaction of SP-A and SP-D with two major mite allergens, Dermatophagoides pteronyssinus 1 and Dermatophagoides farinae 1, and show that the cysteine protease activity of these allergens results in the degradation of SP-A and SP-D under physiological conditions, with multiple sites of cleavage. A recombinant fragment of SP-D that is effective in diminishing allergic hypersensitivity in mouse models of dust mite allergy was more susceptible to degradation than the native full-length protein. Degradation was enhanced in the absence of calcium, with different sites of cleavage, indicating that the calcium associated with SP-A and SP-D influences accessibility to the allergens. Degradation of SP-A and SP-D was associated with diminished binding to carbohydrates and to D. pteronyssinus 1 itself and diminished capacity to agglutinate bacteria. Thus, the degradation and consequent inactivation of SP-A and SP-D may be a novel mechanism to account for the potent allergenicity of these common dust mite allergens.     

Aerobiological and ecological study of the potentially allergenic ornamental plants in south Spain

A number of ornamental plant species produce pollen grains with allergenic properties, thus posing a potential risk to human health. A comparative study of the ecological and aerobiological characteristics of ornamental urban flora in four Andalusian cities revealed the presence of over 100 potentially allergenic ornamental plant species. Most of these were phanerophytes, and species of Asiatic origin predominated, followed by Mediterranean and American species. However, not all potentially allergenic ornamental plants were of aerobiological significance, since some produce only small amounts of pollen, while others were infrequent or were located at a considerable distance from the sampler. Even so, when designing new urban parks and gardens, every effort should be made to ensure maximum species variability avoiding the excessive use of any single species.     

A comparative study of some more important experimental animal peroxide metabolism enzymes.

1. We have studied and compared the peroxide metabolism enzymes (SOD, P and C) of the main organs of fresh-water mollusc, chicken, mouse, guinea-pig, rabbit, cat and dog. 2. The liver exhibited the highest SOD activity. The enzymatic activities of the organ homogenates of the guinea-pig stand out in comparison with the values for the other homogenates examined. 3. The liver, kidney and total brain homogenates of the chicken and the vertebrates display no, or only a very low P activity. The highest P activities were measured in the haemolysates. 4. The C and SOD values exhibit a certain parallelism. 5. The peroxide metabolism enzyme activities calculated by utilizing the protein measurements permit the establishment of a more realistic enzymatic activity.     

A comparative genomics study of genetic products potentially encoding ladderane lipid biosynthesis

Background  

The fatty acids of anaerobic ammonium oxidizing (anammox) bacteria contain linearly concatenated cyclobutane moieties, so far unique to biology. These moieties are under high ring strain and are synthesised by a presently unknown biosynthetic pathway.     

A comparative study of vitamin D binding globulins in milk.

1. The occurrence of 25-hydroxy vitamin D binding protein in human, bovine, monkey and porcine milk was investigated. 2. Sucrose gradient ultracentrifugation revealed the presence of 4.2 S and 5.7 S binding globulins in the whey of human, monkey and porcine milk. 3. Although bovine plasma also contains a 4.2 S globulin only a 5.7 S protein was found in bovine milk. 4. The 4.2 S and 5.7 S globulins in milk could not be resolved by polyacrylamide gel electrophoresis or by isoelectric focusing. 5. Plasma and whey binding proteins of any one species had the same isoelectric point but there were small differences among species (4.5-4.8). 6. Competitive displacement studies showed that the binding proteins in milk have high affinity for 25-hydroxy-cholecalciferol and 24,25-dihydroxycholecalciferol.     

A comparative study of cobra (Naja) venom enzymes

1. The L-amino acid oxidase, hyaluronidase, alkaline phosphomonoesterase, protease, phosphodiesterase, acetylcholinesterase, phospholipase A and 5'-nucleotidase activities of 47 samples of venoms from all the six species of cobra (Naja), including five subspecies of Naja naja, were examined. 2. The results demonstrated interspecific differences in the venom contents of phospholipase A, acetylcholinesterase, hyaluronidase and phosphodiesterase. These differences in venom enzyme contents can be used for the differentiation of species of the genus Naja. 3. Thus, our results revealed a correlation between the enzyme composition of venom and the taxonomic status of the snake at the species level for the genus Naja.     

Drug tolerance and detoxicating enzymes in Octodon degus and Wistar rats. A comparative study

Octodon degus shows greater tolerance to pentobarbital as compared with the Wistar rat. Mixed function oxidase activities in liver microsomes were higher in Octodon degus than in the Wistar rat. The reactions assayed were: aminopyrine N-demethylation, aniline and naphthalene hydroxylation and p-nitroanisole O-demethylation. These higher activities seem to be due mainly to the greater cytochrome P-450 content of liver microsomes of Octodon degus. Glutathione S-transferase activity towards 1-chloro-2,4-dinitrobenzene was 30 times higher in Octodon degus than in the Wistar rat. These results may explain the tolerance of Octodon degus to pentobarbital and other drugs.     

A comparative study of male meiosis in Drosophila melanogaster and D. virilis

Male meiosis in D. melanogaster cytologically follows the usual pattern, whereas in D. melanogaster and in D. virilis oocytes the chromosomes clump into a karyosphere at early meiotic prophase and remain so up to metaphase I.Male meiosis in D. virilis spermatocytes has an intermediate character: a part of the chromatin clumps together in a karyosphere at early prophase, whereas the other part of the chromatin remains diffuse all through prophase. At the end of prophase, the diffuse chromatin becomes integrated into the karyosphere before metaphase I. During the meiotic divisions the chromosomes have the same clumped aspect as those in Drosophila oocytes and thus differ strikingly from the dividing chromosomes in D. melanogaster spermatocytes.In D. virilis spermatocytes the nucleolus exhibits changes during the meiotic prophase that may be related to synthetical activities. The DNA specific staining with the fluorochrome DAPI reveals the existence of extrachromosomal DNA in the later prophase. Other striking differences in meiotic events between the two Drosophila species concern the centrioles and spermiogenesis.     

A comparative molecular dynamics study of thermophilic and mesophilic ribonuclease HI enzymes

We studied a pair of homologous thermophilic and mesophilic ribonuclease HI enzymes by molecular dynamics simulations. Each protein was subjected to three 5 ns simulations in explicit water at both 310 K and 340 K. The thermophilic enzyme showed larger overall positional fluctuations at both temperatures, while only the mesophilic enzyme at the higher temperature showed significant instability. When the temperature is changed, the relative flexibility of different local segments on the two proteins changed differently. Principal component analysis showed that the simulations of the two proteins explored largely overlapping regions in the conformational space. However, at 340 K, the collective structure variations of the thermophilic protein are different from those of the mesophilic protein. Our results, although not in accordance with the view that hyperthermostability of proteins may originate from their conformational rigidity, are consistent with several recent experimental and simulation studies which showed that thermophilic proteins may be conformationally more flexible than their mesophilic counterparts. The decorrelation between conformational rigidity and hyperthermostability may be attributed to the temperature dependence and long range nature of electrostatic interactions that play more important roles in the structural stability of thermophilic proteins.     

Acaricidal effects of herb essential oils against Dermatophagoides farinae and D. pteronyssinus (Acari: Pyroglyphidae) and qualitative analysis of a herb Mentha pulegium(pennyroyal)

This experiment was undertaken to screen the acaricidal effects of herb essential oils (pennyroyal, ylang ylang, citronella, lemon grass, tea tree, and rosemary) at different doses (0.1, 0.05, 0.025, 0.0125, and 0.00625 microliter/cm(2)) and exposure times (5, 10, 20, 20, 30 and 60 min) on house dust mites Dermatophgoides farinae and D. pteronyssinus. The most effective acaricidal components of pennyroyal (Mentha pulegium) were analyzed using a gas chromatography-mass spectrometer (GC-MS). Of these essential oils, the most effective was pennyroyal, which is composed essentially of pulegone (> 99%), at a dose of 0.025 microliter/cm(2), which at an exposure time of 5 min killed more than 98% of house dust mites. In the pennyroyal fumigation test, the closed method was more effective than the open method and maximum acaricidal effect was 100% at 0.025 microliter/cm(2), 60 min. The results show that herb essential oils, in particular, pennyroyal was proved to have potent acaricidal activity.     

The antigenic and allergenic properties of an extract from the house dust mite Dermatophagoides farinae]

To evaluate the antigenic composition and allergenic activity of D. farinae extracts, the methods of rocket and cross immunoelectrophoresis, gel chromatography and the inhibition of the radioallergosorbent test have been used. The presence of 9-20 antigenic components has been established. The fractions of the extract with a molecular weight of 10-200 kD possessed the highest capacity of inhibiting the binding of specific IgE antibodies from the pool of sera from patients sensitized to D. farinae.     

Ultrastructure of the reproductive system of the house dust mitesDermatophagoides farinae andD. pteronyssinus (Acari,Pyroglyphidae) with remarks on spermatogenesis and oogenesis

Several parts of the reproductive system of both sexes ofDermatophagoides farinae andD. pteronyssinus are investigated and compared by light-, scanning electron-, and transmission electron microscopy. New techniques have been employed for scanning of the internal structures of these mites. The male reproductive system consists of unpaired testis, paired vasa deferentia, an accessory gland, ejaculatory duct, and copulatory organ. The female reproductive system consists of bursa copulatrix, ductus bursae, receptaculum seminis, paired ducti receptaculi, ovaries, oviducts, one chorion gland, ovipositor, and oviporus. Testis as well as ovaries are characterized by syncytia of nutritional function. The specifics of spermatogenesis are discussed in connection with sperm transfer. Similarities between the construction of the ovaries and oogenesis in astigmatic mites and telotrophic meroistic ovaries in insects are discussed.