Irreversible inhibition of the thermophilic esterase EST2 from <Emphasis Type="Italic">Alicyclobacillus acidocaldarius</Emphasis>

Kinetic studies of irreversible inhibition in recent years have received growing attention owing to their relevance to problems of basic scientific interest as well as to their practical importance. Our studies have been devoted to the characterization of the effects that well-known acetylcholinesterase irreversible inhibitors exert on a carboxylesterase (EST2) from the thermophilic eubacterium Alicyclobacillus acidocaldarius. In particular, sulfonyl inhibitors and the organophosphorous insecticide diethyl-p-nitrophenyl phosphate (paraoxon) have been studied. The incubation of EST2 with sulfonyl inhibitors resulted in a time-dependent inactivation according to a pseudo-first-order kinetics. On the other hand, the EST2 inactivation process elicited by paraoxon, being the inhibition reaction completed immediately after the inhibitor addition, cannot be described as a pseudo-first-order kinetics but is better considered as a high affinity inhibition. The values of apparent rate constants for paraoxon inactivation were determined by monitoring the enzyme/substrate reaction in the presence of the inhibitor, and were compared with those of the sulfonyl inhibitors. The protective effect afforded by a competitive inhibitor on the EST2 irreversible inhibition, and the reactivation of a complex enzyme/irreversible-inhibitor by hydroxylamine and 2-PAM, were also investigated. The data have been discussed in the light of the recently described dual substrate binding mode of EST2, considering that the irreversible inhibitors employed were able to discriminate between the two different binding sites.     

The Evolution of Mass Cell Suicide in Bacterial Warfare

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Effects of inactivation methods on the analysis of Bacillus atrophaeus endospores using real‐time PCR and MALDI‐TOF‐MS

A wide range of analytical methods are available for the detection and identification of biological warfare agents. These technologies are often hampered in their performance when the inactivated samples are analyzed. To work with pathogens outside of biosafety level 3 laboratories, a complete inactivation is mandatory when appropriate protection equipment is unavailable. When methods of inactivation are used, the detection of bacteria becomes more difficult. In contrast to measuring viable organisms, inactivation steps can have a massive impact on the intrinsic cellular information. This study examined the effects of autoclaving and chemical inactivation methods on Bacillus spores using biological warfare detection setups like real‐time PCR and MALDI‐TOF‐MS. Here, the inactivation of Bacillus atrophaeus spores with formaldehyde, which is a suggested model for biological warfare spore agents, was compared with other inactivation reagents like Wofasteril^®E400, a commercially available decontaminant based on peroxyacetic acid. With Wofasteril^®E400 the critical factor of inactivation time was reduced to about 15 min and a limit of detection of 8500 spores by PCR was still measurable using five‐times‐washed spores. It has also been shown that MALDI‐TOF‐MS peak information can be hampered by inactivation methods.     

Convergent evolution of the Dufour’s gland secretion as a propaganda substance in the slave-making ant genera Protomognathus and Harpagoxenus

Slave-making ants are social parasites which exploit the workforce of heterospecific slaves for their own reproduction, and to this end they have developed a variety of morphological and behavioural adaptations. Furthermore, social parasites utilize the chemical communication system of their hosts by breaking their nestmate recognition code, and some slave-maker species additionally employ semiochemicals as weapons during colony foundation and slaveraiding. Here, we demonstrate the use of such a ‘propaganda allomone’ by the North American myrmicine slave-maker Protomognathus americanus. This substance is produced in the Dufour’s gland and may be employed during slave raids to elicit panic among defending host workers. Slave-maker Dufour’s gland secretions evoked agitation and heightened levels of activity among host workers when applied directly on a host nest, and strong aggressive responses of nestmates when applied onto a host worker. Although the hosts own Dufour’s gland secretion also elicits intra-colonial fights, no support for the hypothesis was found that the slave-maker propaganda substance mimics a fertility signal of the host, as the chemical profile of the gland secretions is highly divergent between the two species. Preliminary results on the chemical composition of the secretion obtained by gas chromatography indicate that the propaganda substance of P. americanus differs from that of the related European slavemaker Harpagoxenus sublaevis, and is thus likely to represent an independent evolutionary development. Received 24 February 2005; revised 28 July 2005 and 2 March 2006; accepted 6 March 2006.     

Multivariate adaptive embedding (MAE) for the identification of bacterial pathogens in the field

In this work, we demonstrate a new classification machine based on multivariate adaptive embedding (MAE) that is capable of a robust identification of potential bacterial biological warfare agents (BWA). By employing Raman spectroscopy, this method proves to be reliable in application, easy to use and while retaining spectral quality, it is much faster than the often used support vector machines (SVM) and other supervised multivariate statistical classification machines. The multivariate adaptive embedding multi‐species classification ability was developed in order to serve as a real‐time detection method for biological threat detection and pathogen identification. A mean classification accuracy of 99.25±0.45% could be achieved with a representative set of biological warfare agents and simulant bacteria as a first approach for a user‐friendly and fieldable classification application for first responders and researchers.     

Proving communal warfare among hunter‐gatherers: The quasi‐rousseauan error

Was human fighting always there, as old as our species? Or is it a late cultural invention, emerging after the transition to agriculture and the rise of the state, which began, respectively, only around ten thousand and five thousand years ago? Viewed against the life span of our species, Homo sapiens, stretching back 150,000–200,000 years, let alone the roughly two million years of our genus Homo, this is the tip of the iceberg. We now have a temporal frame and plenty of empirical evidence for the “state of nature” that Thomas Hobbes and Jean‐Jacque Rousseau discussed in the abstract and described in diametrically opposed terms. All human populations during the Pleistocene, until about 12,000 years ago, were hunter‐gatherers, or foragers, of the simple, mobile sort that lacked accumulated resources. Studying such human populations that survived until recently or still survive in remote corners of the world, anthropology should have been uniquely positioned to answer the question of aboriginal human fighting or lack thereof. Yet access to, and the interpretation of, that information has been intrinsically problematic. The main problem has been the “contact paradox.” Prestate societies have no written records of their own. Therefore, documenting them requires contact with literate state societies that necessarily affects the former and potentially changes their behavior, including fighting.     

Consecuencias de los conflictos armados en la salud mental de niños y adolescentes: revisión de revisiones de la literatura

Introduction:

Armed conflicts affect the mental health of children and adolescents. Their outcomes in these populations have been documented identifying vulnerability and significant biopsychosocial damage as the most common factors.

Objective:

To identify and synthesize the mental health consequences of armed conflicts in children and adolescents.

Materials and methods:

We carried out a comprehensive and systematic search of reviews published until July 2019 in the MEDLINE (Ovid), EMBASE, Cochrane Central Register of Controlled Trials, and LILACS databases, as well as in additional sources. The information was retrieved and analyzed narratively by describing the characteristics and objectives of the studies and the mental health consequences of armed conflicts in three periods of time: pre-armed conflict, during the armed conflict, and post-conflict.

Results.

Out of 587 potentially relevant studies, we finally selected 72. In the pre-armed conflict period, we described in detail the psychological experiences and the anticipatory somatic symptoms. During the conflict, we identified regressive, behavioral, and cognitive symptoms such as enuresis, fear, sadness, aggression, hyperactivity, and inattention, among others. Direct mental health consequences such as adjustment disorders, depression, anxiety, and post-traumatic stress were also identified. Finally, in the post-conflict period, we referred to the transmission of mental health consequences and resilience processes. On the other hand, we reviewed in depth the potential consequences of armed conflicts on biopsychosocial development, morality, identity, culture, education, and society.

Conclusion.

The development of mental health consequences due to the exposure to armed conflicts in these populations is a complex process that depends on the stage of the exposure, the length of the conflict, and contextual factors.     

Hydrolysis and Biodegradation of the Vesicant Agent HT: Two Potential Approaches

HT is a powerful vesicant produced for use as a chemical warfare agent. It is a mixture of 60 wt% 2,2' -dichlorodiethyl sulfide (“HD” or “sulfur mustard”) and 40 wt% bis-(2-(2-chloroethylthio)ethyl) ether (T). Because HT reacts with water to form primarily the alcoholic compounds thiodiglycol (TDG) and bis-(2-(2-hydroxyethylthio)ethyl) ether (T-OH), disposal might be accomplished by combining hydrolysis with biodegradation. The half-lives of H and T in a well-agitated 3.8% HT/water reaction at 90°C were 1.4 and 1.6 minutes, respectively. The concentrations of both compounds were reduced to less than 1 mg/L within about 30 minutes. TDG is readily biodegradable. However, T-OH biodegradability has not been reported previously. HBr treatment converted HT ether-alcohol products to TDG. A comparative study of two hydrolysis/biodegradation approaches is reported here. HT was hydrolyzed (1) in water, and (2) in water then with HBr. Products were used as feed for separate aerobic sequencing batch reactors (SBRs), and bioreactor performances were compared. Although both feed solutions were detoxified in the SBRs, water hydrolysis alone yielded better overall bioreactor operation, a more favorable mass balance, and a simpler process than with the HBr step. Results indicated that although the HBr converted ether-alcohol products to TDG, the HT products were biodegraded with greater efficiency when the HBr treatment was omitted.