Using a multivariate vector-autoregression (VAR) approach, this paper investigates causal relations and dynamic interactions among asset returns, real activity, and inflation in the postwar United States. Major findings are (1) stock returns appear Granger-causally prior and help explain real activity, (2) with interest rates in the VAR, stock returns explain little variation in inflation, although interest rates explain a substantial fraction of the variation in inflation, and (3) inflation explains little variation in real activity. These findings seem more compatible with Fama (1981) than with Geske and Roll (1983) or with Ram and Spencer (1983). VARIOUS THEORETICAL FRAMEWORKS HAVE been developed to explain the negative correlations observed between inflation and real asset returns inthe postwar period. In light of the Fisher hypothesis, and of the commonly held view that stocks and bonds should be a hedge against inflation, these relations are indeed puzzling. Fama (1981), Geske and Roll (1983), Ram and Spencer (1983), James, Koreisha, and Partch (1985), Stulz (1986), and Kaul (1987) all attempt to explain the negative association between stock returns and inflation; and Fama and Gibbons (1982) attempt to explain the negative association between inflation and real interest rates. Fama (1981) hypothesizes that the negative correlation between stock returns and inflation is not a causal relation but that it is proxying for a positive relation between stock returns and real activity and is induced by a negative relation between real activity and inflation. Geske and Roll (1983) argue that stock returns cause (or signal) changes in inflationary expectations because of a chain of macroeconomic events. When stock prices declinein response to anticipated changes in economic conditions, the government, given largely fixed expenditures, will tend to run a deficit. To the extent that the deficit is monetized, expected inflation will rise. Ram and Spencer (1983), however, find evidence of unidirectional causality from inflation to stock returns. Using a vector autoregressive-moving average (VARMA) model, James, Koreisha, and Partch (1985) examine simultaneously the causal links between stock returns, real activity, money supply, and inflation. They find evidence that stock returns signal both changes in real activity and changes in the monetary base, which suggests a link between money supply and real * Department of Finance, Carlson School of Management, University of Minnesota. I would like to thank an anonymous referee and editor for their many helpful comments and advice. 1592The Journal of Finance activity that is consistent with the money supply explanation offered by Geske and Roll.All of these studies recognize the importance of causal relations and discuss them in one way or another. However, two potential drawbacks remain. First, as Mehra (1978) and Sims (1980b) point out, the causal relations observed based on a bivariate causal test may not be robust when other relevant variables are introduced into the vect...

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Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including “safe harboring” techniques shown in other organisms.

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Acyl-homoserine lactone-mediated quorum sensing (QS) regulates diverse activities in many species of Proteobacteria. QS-controlled genes commonly code for production of secreted or excreted public goods. The acyl-homoserine lactones are synthesized by members of the LuxI signal synthase family and are detected by cognate members of the LuxR family of transcriptional regulators. QS affords a means of population density-dependent gene regulation. Control of public goods via QS provides a fitness benefit. Another potential role for QS is to anticipate overcrowding. As population density increases and stationary phase approaches, QS might induce functions important for existence in stationary phase. Here we provide evidence that in three related species of the genus Burkholderia QS allows individuals to anticipate and survive stationary-phase stress. Survival requires QS-dependent activation of cellular enzymes required for production of excreted oxalate, which serves to counteract ammonia-mediated alkaline toxicity during stationary phase. Our findings provide an example of QS serving as a means to anticipate stationary phase or life at the carrying capacity of a population by activating the expression of cytoplasmic enzymes, altering cellular metabolism, and producing a shared resource or public good, oxalate.Burkholderia carrying capacity | glumae | pseudomallei | thailandensis | cell death A cyl-homoserine lactone (AHL)-mediated quorum sensing (QS) regulates diverse activities, including bioluminescence, biofilm formation, motility, and virulence factor formation, in many Proteobacteria (1-3). AHLs are synthesized most typically by members of the LuxI family signal synthases and detected by members of the LuxR family of transcriptional regulators (1-3). A large body of work has characterized the molecular mechanisms of bacterial QS; demonstrating the population-wide benefits that drive QS-mediated cooperative behavior has proven difficult, however. Cooperative activities benefit individuals within a group (4, 5).QS-controlled genes commonly code for the production of extracellular public goods that can be shared by all members of the group regardless of which members produce them. These extracellular products are often important for nutrient acquisition, interspecies competition, or virulence (6-8). In Pseudomonas aeruginosa, QS control of secreted proteases provides fitness benefits, because the proteases are produced only when they can be used efficiently (9). Other potential roles of QS in bacteria have been proposed, including the hypothesis that QS enables bacteria to anticipate population carrying capacity in a given environment. Anticipation of stationary phase might allow individuals to modify their physiology in preparation for survival at population carrying capacity.Here we address the question of whether QS is involved in anticipation of stationary-phase stress in three closely related bacteria: the rice pathogen Burkholderia glumae, the opportunistic human pathogen Burkholderia pseudomallei, and the...

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Myxococcus xanthus undergoes a starvation-induced multicellular developmental program during which cells partition into three known fates: (i) aggregation into fruiting bodies followed by differentiation into spores, (ii) lysis, or (iii) differentiation into nonaggregating persister-like cells, termed peripheral rods. As a first step to characterize cell fate segregation, we enumerated total, aggregating, and nonaggregating cells throughout the developmental program. We demonstrate that both cell lysis and cell aggregation begin with similar timing at approximately 24 h after induction of development. Examination of several known regulatory proteins in the separated aggregated and nonaggregated cell fractions revealed previously unknown heterogeneity in the accumulation patterns of proteins involved in type IV pilus (T4P)-mediated motility (PilC and PilA) and regulation of development (MrpC, FruA, and C-signal). As part of our characterization of the cell lysis fate, we set out to investigate the unorthodox MazF-MrpC toxin-antitoxin system which was previously proposed to induce programmed cell death (PCD). We demonstrate that deletion of mazF in two different wild-type M. xanthus laboratory strains does not significantly reduce developmental cell lysis, suggesting that MazF's role in promoting PCD is an adaption to the mutant background strain used previously.