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At the outset of his work the author repels an accusation which is commonly levelled at the comparative study of primitive religions—that it reduces the highest forms of religious thought to the level of the lowest, and that it is in reality an evidence of a systematic hostility to all religions; “if we admit that the crude cults of the Australian tribes can help us to understand Christianity, for example, is that not supposing that this latter religion proceeds from the same mentality as the..

Comparative secretomics and functional analysis of effectors utilized by the Microbotryum genus of anther-smut fungal pathogens, and their role in host-specificity.

Understanding how pathogens evolve in response to changes in their host is paramount to combating the spread of emergent strains of disease. This is particularly true for plant pathogens that cause billions of dollars of damages to crops globally, every year. Understanding the molecular interactions between pathogens and their hosts therefore sheds light on the coevolutionary arms race that can result in host-specificity and host-shifts in plant pathogens. This research approaches the question of how fungal pathogens interact with their plant hosts utilizing both unique and shared arsenals of secreted proteins (SPs) during infection, and addresses the question of whether alterations to shared SPs or species-specific SPs play a more important role in host-specificity. To answer these questions, we annotated and compared the secretomes of three species from the Microbotryum genus of anther smuts, two closely related sister species that are able to infect each other’s hosts, albeit to reduced degrees, M. lychnidis-dioicae and M. silenes-dioicae, and one distantly related species that is unable to infect either of the other two species’ host plants and vice versa, M. violaceum var. paradoxa. We then characterized the function of the core SP MVLG_02245, an SP found in all three species with differing levels of conservation at the amino acid sequence level, and tested the importance of two species-specific SPs in host specificity, MvSl_01693 and MvSd_09295, via heterologous expression in each sister species. Finally, for future research into the role of SPs in host pathogenicity, we established a site-specific knockout system in Microbotryum using CRISPR Cas9 technology. Our results demonstrate that while host specificity in the Microbotryum genus is likely the result of alterations to the amino acid sequence of several core SPs, expression of novel SPs can have dramatic effects on pathogenicity. The research is therefore the first to identify key proteins involved in host specificity of the Microbotryum genus, and the first to establish a means of site-specific gene modification and knockout in the Microbotryum system using a CRISPR Cas9

Coupling of disulfide bond and distal histidine dissociation in human ferrous cytoglobin regulates ligand binding

Earlier kinetics studies on cytoglobin did not assign functional properties to specific structural forms. Here, we used defined monomeric and dimeric forms and cysteine mutants to show that an intramolecular disulfide bond (C38-C83) alters the dissociation rate constant of the intrinsic histidine (H81) (∼1000 fold), thus controlling binding of extrinsic ligands. Through time-resolved spectra we have unequivocally assigned CO binding to hexa- and penta-coordinate forms and have made direct measurement of histidine rebinding following photolysis. We present a model that describes how the cysteine redox state of the monomer controls histidine dissociation rate constants and hence extrinsic ligand binding

Cause and Effectors: whole genome comparisons reveal shared but rapidly evolving effector sets among host-specific plant-castrating fungi

International audienceWord Count: 240 16 17 Text Word Count: 6,466 1

Mechanisms behind the Madness: How Do Zombie-Making Fungal Entomopathogens Affect Host Behavior To Increase Transmission?

Transmission is a crucial step in all pathogen life cycles. As such, certain species have evolved complex traits that increase their chances to find and invade new hosts. Fungal species that hijack insect behaviors are evident examples. Many of these "zombie-making" entomopathogens cause their hosts to exhibit heightened activity, seek out elevated positions, and display body postures that promote spore dispersal, all with specific circadian timing. Answering how fungal entomopathogens manipulate their hosts will increase our understanding of molecular aspects underlying fungus-insect interactions, pathogen-host coevolution, and the regulation of animal behavior. It may also lead to the discovery of novel bioactive compounds, given that the fungi involved have traditionally been understudied. This minireview summarizes and discusses recent work on zombie-making fungi of the orders Hypocreales and Entomophthorales that has resulted in hypotheses regarding the mechanisms that drive fungal manipulation of insect behavior. We discuss mechanical processes, host chemical signaling pathways, and fungal secreted effectors proposed to be involved in establishing pathogen-adaptive behaviors. Additionally, we touch on effectors' possible modes of action and how the convergent evolution of host manipulation could have given rise to the many parallels in observed behaviors across fungus-insect systems and beyond. However, the hypothesized mechanisms of behavior manipulation have yet to be proven. We, therefore, also suggest avenues of research that would move the field toward a more quantitative future

Is There Really No Crying in Baseball? Examining the Acceptance of Crying in Sport

It is not uncommon to see tears shed by players on both the winning and losing teams, particularly after a championship game. However, sport is also seen as an environment where competitors go to “put their game faces on” and keep their emotions in check, such as during the film A League of Their Own, when a manager tells a sobbing player that “there is no crying in baseball!” The current study sought to examine the extent to which individuals agree with this perspective. Specifically, participants rated the acceptability of crying by males and females in both sport and non-sport scenarios. The results revealed different expectations for emotional reactions in sport as individuals were more accepting of crying in non-sport scenarios than in sport scenarios. Additionally persons with higher levels of restrictive emotionality were particularly likely to believe that crying in sport was not appropriate

Strong modulation of nitrite reductase activity of cytoglobin by disulfide bond oxidation: Implications for nitric oxide homeostasis

Globin-mediated nitric oxide (NO) dioxygenase and nitrite reductase activities have been proposed to serve protective functions within the cell by scavenging or generating NO respectively. Cytoglobin has rapid NO dioxygenase activity, similar to other globins, however, the apparent rates of nitrite reductase activity have been reported as slow or negligible. Here we report that the activity of cytoglobin nitrite reductase activity is strongly dependent on the oxidation state of the two surface-exposed cysteine residues. The formation of an intramolecular disulfide bond between cysteines C38 and C83 enhances the nitrite reductase activity by 50-fold over that of the monomer with free sulfhydryl or 140-fold over that of the dimer with intermolecular disulfide bonds. The NO dioxygenase reactivity of cytoglobin is very rapid with or without disulfide bond, however, binding of the distal histidine following dissociation of the nitrate are affected by the presence or absence of the disulfide bond. The nitrite reductase activity reported here for the monomer with intramolecular disulfide is much higher than of those previously reported for other mammalian globins, suggesting a plausible role for this biochemistry in controlling NO homeostasis the cell under oxidative and ischemic conditions

Effect of the distal histidine on the peroxidatic activity of monomeric cytoglobin

The reaction of hydrogen peroxide with ferric human cytoglobin and a number of distal histidine variants were studied. The peroxidase activity of the monomeric wildtype protein with an internal disulfide bond, likely to be the form of the protein in vivo, exhibits a high peroxidase-like activity above that of other globins such as myoglobin. Furthermore, the peroxidatic activity of wildtype cytoglobin shows increased resistance to radical-based degradation compared to myoglobin. The ferryl form of wildtype cytoglobin is unstable, but is able to readily oxidize substrates such as guaiacol. In contrast distal histidine mutants of cytoglobin (H81Y and H81V) show very low peroxidase activity but enhanced radical-induced degradation. Therefore, the weakly bound distal histidine appears to modulate ferryl stability and limit haem degradation. These data are consistent with a role of a peroxidase activity of cytoglobin in cell stress response mechanisms.</ns4:p

Ultrafast photochemistry of the bc₁ complex

We present a full investigation of ultrafast light-induced events in the membraneous cytochrome bc 1 complex by transient absorption spectroscopy. This energy-transducing complex harbors four redox-active components per monomer: heme c 1 , two 6-coordinate b-hemes and a [2Fe-2S] cluster. Using excitation of these components in different ratios under various excitation conditions, probing in the full visible range and under three well-defined redox conditions, we demonstrate that for all ferrous hemes of the complex photodissociation of axial ligands takes place and that they rebind in 5-7 ps, as in other 6-coordinate heme proteins, including cytoglobin, which is included as a reference in this study. By contrast, the signals are not consistent with photooxidation of the b hemes. This conclusion contrasts with a recent assessment based on a more limited data set. The binding kinetics of internal and external ligands are indicative of a rigid heme environment, consistent with the electron transfer function. We also report, for the first time, photoactivity of the very weakly absorbing iron-sulfur center. This yields the unexpected perspective of studying photochemistry, initiated by excitation of iron-sulfur clusters, in a range of protein complexes