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Archaea are an understudied domain of life often found in “extreme” environments in terms of temperature, salinity, and a range of other factors. Archaeal proteins, such as a wide range of enzymes, have adapted to function under these extreme conditions, providing biotechnology with interesting activities to exploit. In addition to producing structural and enzymatic proteins, archaea also produce a range of small peptide molecules (such as archaeocins) and other novel secondary metabolites such as those putatively involved in cell communication (acyl homoserine lactones), which can be exploited for biotechnological purposes. Due to the wide array of metabolites produced there is a great deal of biotechnological potential from antimicrobials such as diketopiperazines and archaeocins, as well as roles in the cosmetics and food industry. In this review we will discuss the diversity of small molecules, both peptide and nonpeptide, produced by archaea and their potential biotechnological applications.

The functional metagenomic potential of Shark Bay microbial mats was examined for the first time at a millimeter scale, employing shotgun sequencing of communities via the Illumina NextSeq 500 platform in conjunction with defined chemical analyses. A detailed functional metagenomic profile has elucidated key pathways and facilitated inference of critical microbial interactions. In addition, 87 medium-to-high-quality metagenome-assembled genomes (MAG) were assembled, including potentially novel bins under the deep-branching archaeal Asgard group (Thorarchaetoa and Lokiarchaeota). A range of pathways involved in carbon, nitrogen, sulfur, and phosphorus cycles were identified in mat metagenomes, with the Wood–Ljungdahl pathway over-represented and inferred as a major carbon fixation mode. The top five sets of genes were affiliated to sulfate assimilation ( cysNC cysNCD, sat ), methanogenesis ( hdrABC ), Wood–Ljungdahl pathways ( cooS, coxSML ), phosphate transport ( pstB ), and copper efflux ( copA ). Polyhydroxyalkanoate (PHA) synthase genes were over-represented at the surface, with PHA serving as a potential storage of fixed carbon. Sulfur metabolism genes were highly represented, in particular complete sets of genes responsible for both assimilatory and dissimilatory sulfate reduction. Pathways of environmental adaptation (UV, hypersalinity, oxidative stress, and heavy metal resistance) were also delineated, as well as putative viral defensive mechanisms (core genes of the CRISPR, BREX, and DISARM systems). This study provides new metagenome-based models of how biogeochemical cycles and adaptive responses may be partitioned in the microbial mats of Shark Bay.

Quorum sensing is a potent system of genetic control allowing phenotypes to be coordinated across localized communities. In this study, quorum sensing systems in Shark Bay microbial mats were delineated using a targeted approach analyzing whole mat extractions as well as the creation of an isolate library. A library of 165 isolates from different mat types were screened using the AHL biosensor E. coli MT102. Based on sequence identity 30 unique isolates belonging to Proteobacteria, Actinobacteria and Firmicutes were found to activate the AHL biosensor, suggesting AHLs or analogous compounds were potentially present. Several of the isolates have not been shown previously to produce signal molecules, particularly the members of the Actinobacteria and Firmicutes phyla including Virgibacillus, Halobacillius, Microbacterium and Brevibacterium. These active isolates were further screened using thin-layer chromatography (TLC) providing putative identities of AHL molecules present within the mat communities. Nine isolates were capable of producing several spots of varying sizes after TLC separation, suggesting the presence of multiple signalling molecules. This study is the first to delineate AHL-based signalling in the microbial mats of Shark Bay, and suggests quorum sensing may play a role in the ecosphysiological coordination of complex phenotypes across microbial mat communities.

Microbial communication, particularly that of quorum sensing, plays an important role in regulating gene expression in a range of organisms. Although this phenomenon has been well studied in relation to, for example, virulence gene regulation, the focus of this article is to review our understanding of the role of microbial communication in extreme environments. Cell signaling regulates many important microbial processes and may play a pivotal role in driving microbial functional diversity and ultimately ecosystem function in extreme environments. Several recent studies have characterized cell signaling in modern analogs to early Earth communities (microbial mats), and characterization of cell signaling systems in these communities may provide unique insights in understanding the microbial interactions involved in function and survival in extreme environments. Cell signaling is a fundamental process that may have co-evolved with communities and environmental conditions on the early Earth. Without cell signaling, evolutionary pressures may have even resulted in the extinction rather than evolution of certain microbial groups. One of the biggest challenges in extremophile biology is understanding how and why some microbial functional groups are located where logically they would not be expected to survive, and tightly regulated communication may be key. Finally, quorum sensing has been recently identified for the first time in archaea, and thus communication at multiple levels (potentially even inter-domain) may be fundamental in extreme environments.

There have been many studies of the allocation of responsibilities and services among the various levels of government in the United States, but some of them have not been objective; they have advocated transfers from one level to another because of a desire to be rid of a costly activity. The question of how best to allocate services cannot be separated from the availability of tax resources. But the incidence of the principal taxes in America has shifted radically throughout our history. Services should be allocated on the basis of optimum administrative and policy-making considerations, and architects of these optimum arrangements should demand that the appropriate adjustments be made in the tax structure. A detailed examination of administrative and policy-making realities indicates that a number of changes are in order: (1) the states should extend their control over banking, public and private housing, roads, narcotics, civil rights, natural parks, labor relations, public assistance, elections administration, factory inspection, agriculture, uses of leisure, and intrastate utilities. (2) Fragmentized services like public health and education should be taken out of small districts and administered by units large enough to permit professionalization and specialization. (3) Services which are essentially national in scope, like military training and the regulation of insurance, should be transferred from the states to the federal government. Finally, we should promote an extension program of functional consolidation of local governments.

The shorter working day and longer retirement period, plus monotonous and often stultifying jobs in mechanized industry, have created a challenge for recreationists. New objectives and policies must be formulated, and a new jurisdiction must be carved out to supplement existing public education and public welfare programs. Recreationists must become more confident, demandful, and imaginative. They must disseminate the doctrine that the enjoyment of leisure is an end in itself, and that recreation skills should be compulsorily taught. Recreation should be a basic program carrying its own justification and should not be ancillary to correctional and therapeutic programs. On the practical side, the administrative base for recreation should be broadened; expanded recreation funds should be provided out of the education budget; emphasis should be placed on late teen-agers and old people; land should be acquired as quickly as possible; and the professional training of recreationists should be broadened.

National character must be distinguished from national characteristics, and must be assessed over an adequate period of time. Also, the question must be faced as to whether political institutions shape national character more or less than they are shaped by it. The outstanding attributes of national character discernible in recent centuries are particularism, atomism, orderliness, otherworldliness, restraint, a sense of mission, herrenvolkism, mysticism and humility, anthropocentricism, materialism, egalitarianism, traditionalism, logicism, empiricism, experimentalism, and resoluteness. But what of the future? It would appear that as we observe the passng of the bipolar political world and are confronted with the vocal independence of the Third World, there will be an intensification of particularism, both within and among separate countries. Also, it appears that political loyalties will be based increasingly on hate rather than love, which is another reason why we should try to develop an effective world government. Also, the state as a concept and a political entity is fading. Governments are becoming more ephemeral, but they are real and comprehensible, whether they take on the form of a republic, a one-man dictatorship, a one-party dictatorship, or a charismatic executive.

Antarctica, being the coldest, driest and windiest continent on Earth, represents the most extreme environment a living organism can thrive in. Under constant exposure to harsh environmental threats, terrestrial Antarctica remains home to a great diversity of microorganisms, indicating that the soil bacteria must have adapted a range of survival strategies that require cell-to-cell communication. Survival strategies include secondary metabolite production, biofilm formation, bioluminescence, symbiosis, conjugation, sporulation and motility, all of which are often regulated by quorum sensing (QS), a type of bacterial communication. Up to now, such mechanisms have not been explored in terrestrial Antarctica. Here, for the first time, LuxI/LuxR-based quorum sensing (QS) activity was delineated in soil bacterial isolates recovered from Adams Flat, in the Vestfold Hills region of East Antarctica. Interestingly, we identified the production of potential homoserine lactones (HSLs) ranging from medium to long chain length in 19 bacterial species using three biosensors, namely Agrobacterium tumefaciens NTL4, Chromobacterium violaceum CV026 and Escherichia coli MT102, in conjunction with thin layer chromatography (TLC). The majority of detectable HSLs were from gram-positive microorganisms not previously known to produce HSLs. This discovery further expands our understand of the microbial community capable of this type of communication, as well as providing insights into physiological adaptations of microorganisms that allow them to survive in the harsh Antarctic environment.