Estimating downwind concentrations of viable airborne microorganisms in dynamic atmospheric conditions.

A Gaussian plume model has been modified to include an airborne microbial survival term that is a best-fit function of laboratory experimental data of weather variables. The model has been included in an algorithm using microbial source strength and local hourly mean weather data to drive the model through a summer- and winter-day cycle. For illustrative purposes, a composite airborne "virus" (developed using actual characteristics from two viruses) was used to show how wind speed could have a major modulating effect on near-source viable concentrations. For example, at high wind speeds such as those occurring during the day, or with short travel times, near-source locations experience high viable concentrations because the microorganisms have not had time to become inactivated. As the travel time increases, because of slow wind speed or longer distances, die-off modulation by sunshine, relative humidity, temperature, etc., potentially becomes increasingly predominant.     

Evaluation of different Bacillus strains in respect of their ability to produce Surfactin in a model fermentation process with integrated foam fractionation

Biosurfactants increasingly gain attention due to the manifold of possible applications and production on the basis of renewable resources. Owing to its various characteristics, Surfactin is one of the most studied biosurfactants. Since its discovery, several Surfactin producers have been identified, but their capacity to produce Surfactin has not been evaluated in a comparison. Six different Bacillus strains were analyzed regarding their ability to produce Surfactin in model fermentations with integrated foam fractionation, for in situ product enrichment and removal. Three of the investigated strains are commonly used in Surfactin production (ATCC 21332, DSM 3256, DSM 3258), whereas two Bacillus strains are described for the first time (DSM 1090, LM43a50°C) as Surfactin producers. Additionally, the Bacillus subtilis type strain DSM 10^T was included in the evaluation. Interestingly, all strains, except DSM 3256, featured high values for Surfactin recovered from foam in comparison to other studies, ranging between 0.4 and 1.05 g. The fermentation process was characterized by calculating procedural parameters like substrate yield Y _X/S, product yield Y _P/X, specific growth rate μ, specific productivity q _Surfactin, volumetric productivity q _Surfactin, Surfactin and bacterial enrichment as well as Surfactin recovery. The strains differ most in specific and volumetric productivity; nevertheless, it is evident that it is not possible to name a Bacillus strain that is the most appropriate for the production of Surfactin under these conditions. In contrast, it becomes apparent that the choice of a specific strain should depend on the applied fermentation conditions.     

The relative contributions of extracellular and intracellular calcium to secretion from tumor mast cells. Multiple effects of the proton ionophore carbonyl cyanide m-chlorophenylhydrazone

The proton ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) inhibited antigen-stimulated secretion and calcium influx in rat basophilic leukemia cells. In a glucose-free solution the inhibitory effects of CCCP were due to a decrease in the intracellular ATP concentration; however, when glucose was present there was no decrease in ATP. Instead, we found that in a glucose-containing saline solution, CCCP inhibited antigen-stimulated calcium uptake because it depolarized the plasma membrane, which in rat basophilic leukemia cells inhibits antigen-stimulated calcium uptake. In the presence of glucose, relatively low concentrations of CCCP inhibited calcium uptake while higher concentrations were required to inhibit secretion. In contrast, the initial antigen-stimulated rise in cytoplasmic calcium, measured with the fluorescent calcium indicator quin2, was not inhibited by CCCP. This suggests that the release of calcium from intracellular stores might, in some cases, be sufficient to support antigen-stimulated secretion. In the presence of CCCP the pH gradient becomes important for regulating the membrane potential across the plasma membrane. When cells were depolarized with CCCP and the external pH was increased, the membrane potential returned to resting levels and antigen-stimulated calcium uptake was restored. Inhibition of antigen-stimulated secretion by higher concentrations of CCCP could also be reversed by increasing the external pH.     

Induction of malignant transformation in vitro and mammary tumors in rats by two new potent anthracycline antitumor antibiotics,morpholinodaunomycin and cyanomorpholinoadriamycin

The two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin, are nonmutagenic or weakly mutagenic in Salmonella typhimurium or V79 Chinese hamster cells, but highly active inducing DNA repair in in cultured rat hepatocytes. Both agents were found to induce malignant transformation in vitro of C3H M2 mouse fibroblasts and mammary tumors in female Sprague-Dawley rats. The data indicate a) that these new anthracyclines, too, are highly oncogenic and b) in conjunction with previously published results, that the predictive value of in vitro short-term tests for in vivo carcinogenicity is dependent on the employment of a battery of such tests.Abbreviations ADM adriamycin - CNMoADM cyanomorpholinoadriamycin - DNM daunomycin - MNNG N-methyl-N-nitro-N-nitrosoguanidine Dedicated to Dr. J.H. Weisburger on his 65th birthday     

Coaction of three factors controlling chlorophyll and anthocyanin synthesis

In a three-factor analysis the rate of chlorophyll a (Chl) accumulation in excised mustard cotyledons was studied as a function of kinetin, light (operating through phytochrome, P _fr) and an excision factor. It was found that the three factors operate additively provided that the P _fr level is high enough. When the P _fr level is below approximately 1 per cent (<0.01) the effectiveness of the excision factor decreases while the effect of kinetin remains additive. The observed additivity is explained by a model where the three factors operate independently through a common intermediate (presumably 5-aminolevulinate) in the biosynthetic chain leading to Chl. With regard to the coaction of the excision factor and phytochrome it is concluded that the production of the excision factor requires the operation of phytochrome (even though saturated at a low P _fr level) while the action of the excision factor is independent of phytochrome. This conclusion was confirmed by experiments in which the rate of light-mediated anthocyanin synthesis was measured in excised mustard cotyledons. The effect of excision in the case of anthocyanin formation differs kinetically from the effect of excision on Chl formation.Abbreviations Chl chlorophyll(ide) a - P _fr far-red absorbing form of phytochrome - P _fr/P _tot ratio at photoequilibrium - RL red light - FR far-red light - GL green light - RG9 light long wavelength far-red light - WL white light     

Steuerung und potentielle Evolutionsgeschwindigkeit des obligaten Teilzieherverhaltens: Ergebnisse eines Zweiweg-Selektionsexperiments mit der M?nchsgrasmücke (Sylvia atricapilla)

Zusammenfassung 1. In Südfrankreich lebt eine obligat teilziehende Population der Mönchsgrasmücke (Sylvia atricapilla) mit rund drei Vierteln Zugvögeln und einem Viertel Standvögeln. Das Teilzugverhalten dieser Population wird in beträchtlichem Umfang von genetischen Faktoren gesteuert (Berthold &Querner 1982). Der starke Selektionserfolg eines Zweiweg-Selektionsexperiments bis zur F₁-Generation ließ eine hohe potentielle Evolutionsgeschwindigkeit des obligaten Teilzieherverhaltens vermuten (2). Wir haben das Evolutionspotential in einem Langzeit-Selektionsversuch experimentell untersucht.2. Wir zogen insgesamt 267 Individuen der freilebenden Mönchsgrasmückenpopulation in fünf Gruppen von Hand auf, und alle fünf Stichproben zeigten entsprechende Verhältnisse von Ziehern und Nichtziehern. Wir konnten das Langzeit-Zweiweg-Selektionsexperiment bis zu einer F₆-Generation durchführen und konnten dabei insgesamt 455 Mönchsgrasmücken in Volieren züchten.3. Das Zweiweg-Selektionsexperiment zeigt, daß die untersuchte teilziehende Mönchsgrasmückenpopulation bereits nach drei Generationen eine ausschließlich ziehende und nach vier bis sechs Generationen eine fast nicht mehr ziehende Population werden kann.4. Das Zweiweg-Selektionsexperiment zeigt starken Selektionserfolg und hohe Heritabilitätswerte (ca. 0,6–1), die deutlich höher liegen als bisher für das Verhalten von (meist domestizierten) Wirbeltieren angegeben. Demnach sind genetische Faktoren für die Steuerung dieses obligaten Teilzugs sehr bedeutsam und wahrscheinlich dominant über Umwelteinflüsse.5. Die Versuchsergebnisse lassen im Falle von schnellen Umweltveränderungen und der Wirkung von starken Selektionsfaktoren ein enorm großes Evolutionspotential des obligaten Teilzieherverhaltens annehmen und damit allgemein eine schnelle Mikroevolution der Ortsbewegung von Vögeln. Sollten die von Meteorologen prophezeiten Klimaänderungen in Bälde eintreten (Erwärmung aufgrund von Verunreinigungen der Atmosphäre durch den Menschen, Treibhauseffekt), dann könnten viele obligate Teilzieher auf genetischer Basis rasch zu Standvögeln werden und wenig ausgeprägte Zieher rasch zu Teilziehern. Unter diesem allgemeinen Anwachsen von Standvögeln könnten ausgeprägte Zugvögel mehr und mehr zu leiden haben.6. Eine genetische Kontrolle obligaten Teilzugs scheint weit verbreitet zu sein, und sie stellt wohl auch für alle Individuen den zuverlässigsten Steuerungsmechanismus dar. Beim fakultativen Teilzug hingegen dürften Umweltfaktoren mehr unmittelbar steuernd wirken.

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Control and evolutionary potential of obligate partial migration: results of a two-way selective breeding experiment with the Blackcap (Sylvia atricapilla)

Summary 1. In southern France breeds an obligate partially migratory population of the Blackcap with about three quarters of migrants and one quarter of residents. Partial migration of this population is considerably controlled by genetic factors (Berthold &Querner 1982). The large selection response of a two-way selective breeding experiment up to F₁-generations suggested a high evolutionary potential of obligate partial migration (2). We have this evolutionary potential experimentally investigated in a long-term selective breeding study.2. We raised by hand a total of 267 individuals of the free-living Blackcap population in five groups, and all five samples showed corresponding ratios of migrants and nonmigrants. We were able to conduct the long-term selective breeding experiment up to a F₆-generation, and thereby a total of 455 Blackcaps could be bred in aviaries.3. The two-way selective breeding experiment shows, that the investigated partially migratory Blackcap population can become completely migratory in just three generations and almost exclusively sedentary in just four to six generations.4. The two-way selective breeding experiment yielded large selection responses and high heritability values (about 0.6–1) which are distinctly higher than those previously reported for behavioural traits of (mostly domesticated) vertebrates. Hence, genetic factors are very important for the control of this obligate partial migration and are presumedly dominant over environmental influences.5. In case of rapid environmental changes and the effect of strong selection factors the experimental results suggest a strikingly high evolutionary potential of obligate partial migration and thus in general a rapid microevolution of bird movements. If climatic changes would occur in the near future as they are predicted by meteorologists (rise in temperature due to man-made pollution of the atmosphere, greenhouse-effect) then many obligate partial migrants could rapidly become sedentary on a genetic basis and many less typical migrants could then considerably suffer from the general increase of residents.6. A genetic control of obligate partial migration appears to be widespread and it also appears to be the most reliable control mechanism for all individuals of such a partially migratory population. Facultative partial migration, however, appears to be controlled more directly by environmental factors.

     

Making Activity Recognition Robust against Deceptive Behavior

Healthcare services increasingly use the activity recognition technology to track the daily activities of individuals. In some cases, this is used to provide incentives. For example, some health insurance companies offer discount to customers who are physically active, based on the data collected from their activity tracking devices. Therefore, there is an increasing motivation for individuals to cheat, by making activity trackers detect activities that increase their benefits rather than the ones they actually do. In this study, we used a novel method to make activity recognition robust against deceptive behavior. We asked 14 subjects to attempt to trick our smartphone-based activity classifier by making it detect an activity other than the one they actually performed, for example by shaking the phone while seated to make the classifier detect walking. If they succeeded, we used their motion data to retrain the classifier, and asked them to try to trick it again. The experiment ended when subjects could no longer cheat. We found that some subjects were not able to trick the classifier at all, while others required five rounds of retraining. While classifiers trained on normal activity data predicted true activity with ~38% accuracy, training on the data gathered during the deceptive behavior increased their accuracy to ~84%. We conclude that learning the deceptive behavior of one individual helps to detect the deceptive behavior of others. Thus, we can make current activity recognition robust to deception by including deceptive activity data from a few individuals.     

Identification of deficient mitochondrial signaling in apoptosis resistant leukemia cells by flow cytometric analysis of intracellular cytochrome c, caspase-3 and apoptosis

Deficient activation of apoptosis signaling pathways may be responsible for treatment failure of malignant diseases. In primary leukemia samples the detection of deficient mitochondrial apoptosis signaling would enable identification of chemo-resistant cells. To investigate the key events of apoptosis at the mitochondrial level, we developed a flow cytometric method for simultaneous detection of mitochondrial cytochrome c release and caspase-3 processing using conformation sensitive monoclonal antibodies. This method proved to identify deficient mitochondrial apoptosis signaling in leukemia cells overexpressing Bcl-2 by a pattern of apoptosis resistance, deficient cytochrome c reduction and partial processing of caspase-3. In primary leukemia cells, reduction of cytochrome c and caspase-3 activation was induced by treatment with anticancer drugs in vitro. In leukemia cells of a patient with resistant disease, a pattern of deficient apoptosis signaling as in Bcl-2 transfected cells was observed, suggesting that deficient mitochondrial signaling contributed to the clinical phenotype of drug resistance in this patient. Flow cytometric analysis of mitochondrial apoptosis signaling may provide a useful tool for the prediction of drug resistance and treatment failure in primary leukemia.     

Ribosomal protein-sequence block structure suggests complex prokaryotic evolution with implications for the origin of eukaryotes

Amino acid sequence alignments of orthologous ribosomal proteins found in Bacteria, Archaea, and Eukaryota display, relative to one another, an unusual segment or block structure, with major evolutionary implications. Within each of the prokaryotic phylodomains the sequences exhibit substantial similarity, but cross-domain alignments break up into (a) universal blocks (conserved in both phylodomains), (b) bacterial blocks (unalignable with any archaeal counterparts), and (c) archaeal blocks (unalignable with any bacterial counterparts). Sequences of those eukaryotic cytoplasmic riboproteins that have orthologs in both Bacteria and Archaea, exclusively match the archaeal block structure. The distinct blocks do not correlate consistently with any identifiable functional or structural feature including RNA and protein contacts. This phylodomain-specific block pattern also exists in a number of other proteins associated with protein synthesis, but not among enzymes of intermediary metabolism. While the universal blocks imply that modern Bacteria and Archaea (as defined by their translational machinery) clearly have had a common ancestor, the phylodomain-specific blocks imply that these two groups derive from single, phylodomain-specific types that came into existence at some point long after that common ancestor. The simplest explanation for this pattern would be a major evolutionary bottleneck, or other scenario that drastically limited the progenitors of modern prokaryotic diversity at a time considerably after the evolution of a fully functional translation apparatus. The vast range of habitats and metabolisms that prokaryotes occupy today would thus reflect divergent evolution after such a restricting event. Interestingly, phylogenetic analysis places the origin of eukaryotes at about the same time and shows a closer relationship of the eukaryotic ribosome-associated proteins to crenarchaeal rather than euryarchaeal counterparts.