Four-hourly fluctuations in grass-pollen concentrations in relation to wet versus dry weather,and to short versus long over-land advection

Four-hourly volumetric measurements of airborne grass-pollen concentrations at Leiden, near the west coast of the Netherlands, were analyzed according to wet-versus-dry meteorological conditions in the pollen source area, and according to the distance of the over-land advection to the pollen sampler. Airborne pollen concentrations appear to be low when the source surface is wet by past or present rain, fog, or dew; and high when the source area is dry. Air adverted over long over-land distances from dry source areas contains much pollen, especially in the afternoon, due to pollen release and decreasing air turbulence. High nightly pollen concentrations are observed after a warm and dry day with much pollen release in distant source areas when the nocturnal meteorological conditions stimulate concentration of pollen grains into the lower layers of the atmosphere.Presented at the Sixth International Palynological Conference, 26 August – 1 September 1984, Calgary, Canada.     

L'action de l'air ionisé dans le traitement des ulcères gastroduodénaux (Données expérimentales chez le rat et essais cliniques)

Résumé Par un jeûne de trois jours ou par l'administration per os de réserpine(2 à 4 mg/kg) durant 15 à 24 jours, on a provoqué des ulcères d'estomac chez des rats. Une partie des bÊtes ainsi traitées fut exposée durant cette période et pendant 2 heures par jour à un air ionisé contenant 5.000 à 15.000 petits ions par cm³ d'air. Pour les animaux soumis au jeûne, la proportion d'ulcères se monte à 93% chez les bÊtes de contrÔle, alors qu'elle n'est que de 59% chez les bÊtes traÎtées par l'air ionisé. Pour les rats traÎtés à la réserpine, les proportions sont de 83,respectivement de 45%. On a en outre exposé 66 patients atteints d'ulcères d'estomac et d'intestins durant 12 à 15 jours et pendant 15 à 45 minutes par jour à un air contenant 5.000 à 10.000 petits ions négatifs par cm³ d'air. Pour 38 d'entre eux, la douleur et les autres symptÔmes avaient diminué ou disparu après le traitement.

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Gastric ulcers were produced in rats by starvation for 3 days or the administration of reserpine (2 to 4 mg/kg) for 15 to 24 days. Some of the animals were exposed to ionized air for 2 hours daily during these periods(5,000 to 15,000 small negative ions/m3 air). The incidence of ulcer development was 93% in the untreated starved rats and 59% in those treated with ionized air; 83% in the animals treated with reserpine and 45% in those with additional ionized air treatment. In a clinical investigation 66 patients with peptic ulcer were exposed for 12 to 15 days to 5,000 to 10,000 small negative ions/m³ air daily. Pain and other symptoms were diminished or abolished after this treatment in 38 patients.

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Zusammenfassung Bei Ratten wurden durch 3 Tage Hungern oder Behandlung mit Reserpin (2–4 mg/kg) wÄhrend 15 bis 24 Tagen Magenulcera provoziert. Ein Teil der Tiere wurde wÄhrend dieser Perioden 2 Std. tÄglich ionisierter Luft exponiert (5.000–15.000 kleine Ionen/m3 Luft). Die Ulcusrate betrug bei den unbehandelten Hungertieren 93%, bei den mit ionisierter Luft behandelten 59%; bei den Reserpin behandelten Tieren betrug sie 83% und bei den zusÄtzlich mit ionisierter Luft behandelten 45%. In der Klinik wurden 66 Patienten mit Magen-Darmulcera 12–15 Tage lang 15–45 min tÄglich mit 5.000 –10.000 neg. kleinen Ionen/m3 Luft behandelt. In 38 Patienten waren nach der Behandlung der Schmerz und die anderen Symptome abgeschwÄcht oder verschwunden.

     

City spore concentrations in the European Economic Community (EEC). VI. Poaceae (Grasses), 1982–1986

Summary Airborne grass-pollen concentrations in six cities in the EEC are compared, based on observations from five years, 1982–1986. Results show that there are quantitative differences both between the monitoring stations and between the years. Very provisionally, the average seasonal total of the European urban airborne grass-pollen concentration can be put at 4 to 5000 per m³ of air. Also qualitatively, regarding the seasonal fluctuations, there are differences between the stations, and between the years. Generally, the results confirm that June is the most typical grass-pollen month in northwestern Europe, whereas in mediterranean Europe May is the more prominent grass-pollen period. There seems to be little coherence between the starting dates of the grass-pollen season even at relatively nearby stations in northwestern Europe, suggestive for a great influence of the actual weather situation.     

Excretion of proteins by gram-negative bacteria: export of bacteriocins and fimbrial proteins byEscherichia coli

In gram-negative bacteria only few proteins are exported across both the cytoplasmic membrane and the outer membrane which forms an extra barrier for protein excretion. In this review we describe the mechanisms of production and export of two types of plasmid-encoded proteins inEscherichia coli. These proteins are the bacteriocin cloacin DF13 and the K88ab and K99 fimbrial subunits. Specific so-called helper proteins located at different positions in the cell envelope play an essential role in the export of these proteins. The genetic organization, subcellular location and functions of these helper proteins, as well as the effects of mutations and culture conditions on the export of the proteins are described. Models for the export mechanisms are presented and future application possibilities for engineering foreign protein excretion inE. coli with these export systems are discussed.     

The Evolution of Feeding Motor Patterns in Lizards: Modulatory Complexity and Possible Constraints

Previous research indicated that the evolution of feeding motorpatterns across major taxonomic groups might have occurred withoutlarge modifications of the control of the jaw and hyolingualmuscles. However, the proposal of this evolutionary scheme washampered by the lack of data for some key taxa such as lizards.Recent data on jaw and hyolingual feeding motor patterns ofa number of lizard families suggest extensive variability withinand among species. Although most lizards respond to changesin the structural properties of food items by modulating theactivation of the jaw and hyolingual muscles, some food specialistsmight have lost this ability. Whereas the overall similarityin motor patterns across different lineages of lizards is largefor the hyolingual muscles, jaw muscle activation patterns seemto be more flexible. Nevertheless, all data suggest that boththe jaw and hyolingual system are complexly integrated. Theelimination of feedback pathways from the hyolingual systemthrough nerve transection experiments clearly shows that feedingcycles are largely shaped by feedback interactions. Yet, novelmotor patterns including unilateral control seem to have emergedin the evolution from lizards to snakes.     

Spacers increase the accessibility of peptide ligands linked to the carboxyl terminus of adenovirus minor capsid protein IX

The efficiency and specificity of gene transfer with human adenovirus (hAd)-derived gene transfer vectors would be improved if the native viral tropism could be modified. Here, we demonstrate that the minor capsid protein IX (pIX), which is present in 240 copies in the Ad capsid, can be exploited as an anchor for heterologous polypeptides. Protein IX-deleted hAd5 vectors were propagated in hAd5 helper cells expressing pIX variants, with heterologous carboxyl-terminal extensions of up to 113 amino acids in length. The extensions evaluated consist of alpha-helical spacers up to 75 A in length and to which peptide ligands were fused. The pIX variants were efficiently incorporated into the capsids of Ad particles. On intact particles, the MYC-tagged-pIX molecules were readily accessible to anti-MYC antibodies, as demonstrated by electron microscopic analyses of immunogold-labeled virus particles. The labeling efficiency improved with increasing spacer length, suggesting that the spacers lift and expose the ligand at the capsid surface. Furthermore, we found that the addition of an integrin-binding RGD motif to the pIX markedly stimulated the transduction of coxsackievirus group B and hAd receptor-deficient endothelioma cells, demonstrating the utility of pIX modification in gene transfer. Our data demonstrate that the minor capsid protein IX can be used as an anchor for the addition of polypeptide ligands to Ad particles.     

Adenylate kinase derived ATP shapes respiration and calcium storage of isolated mitochondria

The ratio of ADP and ATP is a natural indicator of cellular bioenergetic state and thus a prominent analyte in metabolism research. Beyond adenylate interconversion via oxidative phosphorylation and ATPase activities, ADP and ATP act as steric regulators of enzymes, e.g. cytochrome C oxidase, and are major factors in mitochondrial calcium storage potential. Consideration of all routes of adenylate conversion is critical to successfully predict their abundance in an experimental system and to correctly interpret many aspects of mitochondrial function.We showcase here how adenylate kinases elicit considerable impact on the outcome of a variety of mitochondrial assays through their drastic manipulation of the adenylate profile. Parameters affected include cytochrome c oxidase activity, P/O ratio, and mitochondrial calcium dynamics. Study of the latter revealed that the presence of ATP is required for mitochondrial calcium to be shaped into a particularly dense form of mitochondrial amorphous calcium phosphate.     

Polyphenolic compounds are novel protective agents against lipid membrane damage by α-synuclein aggregates in vitro

Cumulative evidence now suggests that the abnormal aggregation of the protein α-synuclein (αS) is a critical factor in triggering neurodegeneration in Parkinson's disease (PD). In particular, a fundamental pathogenetic mechanism appears to involve targeting of neuronal membranes by soluble oligomeric intermediates of αS, leading to their disruption or permeabilisation. Therefore, a model assay was developed in which fluorophore-loaded unilamellar vesicles were permeabilised by soluble oligomers, the latter formed by aggregation of human recombinant αS protein. The αS oligomers induced an impairment of membrane integrity similar to that of the pore-forming bacterial peptide gramicidin. The lipid vesicle permeabilisation assay was then utilised to screen 11 natural polyphenolic compounds, 8 synthetic N'-benzylidene-benzohydrazide compounds and black tea extract for protection against membrane damage by wild-type and mutant (A30P, A53T) synuclein aggregates. A select group of potent inhibitory compounds included apigenin, baicalein, morin, nordihydroguaiaretic acid, and black tea extract. Structure-activity analysis further suggests that a 5,7-dihydroxy-chromen-4-one moiety appears to be favourable for the inhibition reaction. In conclusion, we have identified a group of polyphenols that can effectively hinder membrane damage by αS aggregates. These may serve as a viable source of lead compounds for the development and design of novel therapeutic agents in PD.     

Function and regulation of Alx4 in limb development: complex genetic interactions with Gli3 and Shh

The role of the aristaless-related homeobox gene Alx4 in antero-posterior (AP-) patterning of the developing vertebrate limb has remained somewhat elusive. Polydactyly of Alx4 mutant mice is known to be accompanied by ectopic anterior expression of genes like Shh, Fgf4 and 5'Hoxd. We reported previously that polydactyly in Alx4 mutant mice requires SHH signaling, but we now show that in early Alx4-/- limb buds the anterior ectopic expression of Fgf4 and Hoxd13, and therefore disruption of AP-patterning, occurs independently of SHH signaling. To better understand how Alx4 functions in the pathways that regulate AP-patterning, we also studied genomic regulatory sequences that are capable of directing expression of a reporter gene in a pattern corresponding to endogenous Alx4 expression in anterior limb bud mesenchyme. We observed, as expected for authentic Alx4 expression, expansion of reporter construct expression in a Shh-/- background. Total lack of reporter expression in a Gli3-/- background confirms the existence of Gli3-dependent and -independent Alx4 expression in the limb bud. Apparently, these two modules of Alx4 expression are linked to dissimilar functions.