Transiently heritable fates and quorum sensing drive early IFN-I response dynamics.

Type I interferon (IFN-I)-mediated antiviral responses are central to host defense against viral infections. Crucial is the tight and well-orchestrated control of cellular decision-making leading to the production of IFN-Is. Innovative single-cell approaches revealed that the initiation of IFN-I production is limited to only fractions of 1-3% of the total population, both found in vitro, in vivo, and across cell types, which were thought to be stochastically regulated. To challenge this dogma, we addressed the influence of various stochastic and deterministic host-intrinsic factors on dictating early IFN-I responses, using a murine fibroblast reporter model. Epigenetic drugs influenced the percentage of responding cells. Next, with the classical Luria-Delbrück fluctuation test, we provided evidence for transient heritability driving responder fates, which was verified with mathematical modeling. Finally, while studying varying cell densities, we substantiated an important role for cell density in dictating responsiveness, similar to the phenomenon of quorum sensing. Together, this systems immunology approach opens up new avenues to progress the fundamental understanding on cellular decision-making during early IFN-I responses, which can be translated to other (immune) signaling systems.

When we start to develop a cold, influenza or another viral infection, some of our cells produce signaling molecules known as type I interferons (or IFN-Is for short). These early IFN-I signals establish defenses against viruses in both infected and as yet uninfected cells. If the cells produce too much IFN-Is, however, it can result in uncontrolled inflammation that may harm the body and cause life threatening illness. Individual cells need to tightly control how much IFN-Is they produce and match this with the course of the viral infection. They also need to assess how much IFN-I their neighbors are producing and adjust their behavior accordingly. Cells have evolved a myriad of mechanisms to ensure the right amounts of IFN-Is are produced in different circumstances. Broadly, these mechanisms can be divided into two categories: stochastic regulation and deterministic regulation. Stochastic regulation occurs when individual cells receive the exact same information, but this leads to different outcomes, such as, different cells producing various quantities of IFN-Is. In contrast, deterministic regulation causes the same outcome in different cells independent on the information they receive. It was thought that stochastic regulation is the main driver of early IFN-1 responses, but recently a handful of studies have reported deterministic regulation being primarily responsible, instead. Here, Van Eyndhoven et al. explored the roles of both types of regulation in the early IFN-I responses of mouse cells. Van Eyndhoven et al. used genetic approaches and mathematical modelling to show that the fraction of cells that initiate early IFN-I responses can be considered deterministic. Moreover, this deterministic feature turned out to be heritable, such that the fate to produce IFN-I gets passed on for several generations of cells. Additionally, the experiments suggest that cell density, that is, how tightly packed together the cells are, plays an important role in controlling how many cells make IFN-I, with a lower cell density resulting in a higher fraction of cells producing IFN-Is. The findings of Van Eyndhoven et al. add to a growing body of evidence reporting heritable states that can guide decision-making in individual cells. Furthermore, it revises our view on how individual immune cells coordinate population-wide responses.

Study of the concentration of the herbicide (2,4-dichlorophenoxy)-acetic acid in coca leaves and paste obtained from plants treated with this herbicide.

The herbicide (2,4-dichlorophenoxy)-acetic acid (2,4-D) is considered to be the most cost-effective for eradicating illicit coca plants. Since coca leaves are chewed by the natives of coca producing areas, and, since coca paste and cocaine are widely abused, a study was undertaken to determine whether 2,4-D is translocated into the leaves and transferred to coca paste when coca plants are treated with this herbicide. The study concluded that basal treatment of coca plants with 2,4-D ester resulted in translocation of 2,4-D into the leaves, and this herbicide was detected in high concentrations one week after treatment. Coca paste prepared from leaves obtained from basally treated plants did not contain 2,4-D. Foliage spraying resulted in extremely high concentrations of 2,4-D in the leaves, with significantly high concentrations of the herbicide found one week after spraying. Trace amounts of 2,4-D were detected in coca paste prepared from plants sprayed by the foliage method.

High pressure liquid chromatographic determination of the five major alkaloids in Papaver somniferum L. and thebaine in Papaver bracteatum Lindl. capsular tissue.

A high pressure liquid chromatographic isocratic procedure is described for determining and quantitating the 5 major alkaloids narcotine, papaverine, thebaine, codeine, and morphine in Papaver somniferum L. and thebaine in Papaver bracteatum Lindl. Other papaveraceous alkaloids, including salutaridine, oripavine, laudanosine, isothebaine, cryptopine, alpinigenine, narceine, protopine, and gnoscopine, were also quantitated. The values for morphine, codeine, and thebaine in P. somniferum were in agreement within 5--9% with values obtained by the United Nations Narcotics Laboratory by other methods. In contrast to previously reported procedures, the advantage of this method is that no precolumn or other purification other than solvent extraction of the capsular tissue is necessary. Isocratic chromatography alone on a single column resolved the 5 major alkaloids.

Papaver bracteatum Lindl.: quantitative extraction and determination of thebaine.

An interlaboratory procedure for the quantitative extraction and analysis of thebaine from different tissues of Papaver bracteatum Lindl. is presented. Each step was evalutated for the yield of thebaine by use of 1-3H-thebaine and GLC. The method of drying and milling of tissue and the size of resultant particles were important factors in the quantitative recovery of thebaine.

Thebaine content of selections of Papaver bracteatum Lindl. at different ages.

Approximately 200 accessions of Papaver species were evaluated for identification as P. bracteatum Lindl. and for thebaine content. Fifteen authentic P. bracteatum accessions were selected on the basis of chromosome count. Statistical analyses of variation in alkaloid content were made for these accessions. Four of the 15 warranted further study based on the vigor of the plant and the total thebaine present in the tissue. Significant variability in thebaine content was found in wild strains of P. bracteatum, thus requiring genetic selection studies. The data showed that total yield potential of thebain should be considered in selecting P. bracteatum strains for commercial growth rather than concentrating on strains that produce the highest thebaine concentrations. A method for the quantitative estimation of thebaine from P. bracteatum is presented.

Rapid semi-quantitative spot test for determination of thebaine and differentiation of Papaver bracteatum from P. orientale and P. pseudo-orientale.

The alkaloids, orientalidine, oripavine, thebaine, narceine, narceine, codeine, papaverine, isothebaine, alpenigenine and morphine react with a solution of sulfuric acid containing molybdate to give specific colors. Using the acid solution permitted the differentiation of Papaver bracteatum latex from P. orientale latex and P. pseudo-orientale latex.

Pyrolysis-gas-liquid chromatography of fungi: differentiation of species and strains of several members of the Aspergillus flavus group.

Four fungi of the Aspergillus flavus group were differentiated to the species level and strain level by pyrolysis-gas-liquid chromotography. Comparisons of pyrochromatograms revealed more similarities than dissimilarities among both species and strains in the pyrolytic elution patterns. Quantitative analysis was made by comparing the number of peaks in which two strains or reference species agreed or disagreed, the degree of superimposability between the pyrolytic elution patterns of strains and reference species, and the presence or absence of peaks for strain pairs within each species. The accuracy and precision of these techniques suggest that pyrolysis-gas-liquid chromatography may have wide application in the detection, enumeration, and identification of fungi by nonmycologically trained personnel.