Organization and evolution of the glandular kallikrein locus in Mus musculus

The gene of tissue kallikrein and closely related genes constitute the glandular kallikrein (GK) gene family. The number of members varies between species, ranging from three human to 25 murine. Recently, the gene family was extended with 12 new members, KLK4-KLK15, that were identified adjacent to the classical GK genes on human chromosome 19. In this report, the structure and phylogeny of the mouse GK gene locus are described. A comparison of the human and murine loci shows that the locations of the tissue kallikrein gene and KLK4-KLK15 are conserved. The region between the tissue kallikrein gene and KLK15, devoid of genes in human, is expanded and contains 23 classical GK genes in mouse. Downstream of KLK15, where the genes encoding PSA and hK2 are located in human, mouse carries the pseudogene PsimGK25. Phylogenetic analyses show that classical GK genes emerged after the separation of the primate and rodent lineages, forming a subgroup within the newly extended GK family.     

Gene and genome duplications in vertebrates: the one-to-four (-to-eight in fish) rule and the evolution of novel gene functions

One important mechanism for functional innovation during evolution is the duplication of genes and entire genomes. Evidence is accumulating that during the evolution of vertebrates from early deuterostome ancestors entire genomes were duplicated through two rounds of duplications (the 'one-to-two-to-four' rule). The first genome duplication in chordate evolution might predate the Cambrian explosion. The second genome duplication possibly dates back to the early Devonian. Recent data suggest that later in the Devonian, the fish genome was duplicated for a third time to produce up to eight copies of the original deuterostome genome. This last duplication took place after the two major radiations of jawed vertebrate life, the ray-finned fish (Actinopterygia) and the sarcopterygian lineage, diverged. Therefore the sarcopterygian fish, which includes the coelacanth, lungfish and all land vertebrates such as amphibians, reptiles, birds and mammals, tend to have only half the number of genes compared with actinopterygian fish. Although many duplicated genes turned into pseudogenes, or even 'junk' DNA, many others evolved new functions particularly during development. The increased genetic complexity of fish might reflect their evolutionary success and diversity.     

Genetic variation: molecular mechanisms and impact on microbial evolution

On the basis of established knowledge of microbial genetics one can distinguish three major natural strategies in the spontaneous generation of genetic variations in bacteria. These strategies are: (1) small local changes in the nucleotide sequence of the genome, (2) intragenomic reshuffling of segments of genomic sequences and (3) the acquisition of DNA sequences from another organism. The three general strategies differ in the quality of their contribution to microbial evolution. Besides a number of non-genetic factors, various specific gene products are involved in the generation of genetic variation and in the modulation of the frequency of genetic variation. The underlying genes are called evolution genes. They act for the benefit of the biological evolution of populations as opposed to the action of housekeeping genes and accessory genes which are for the benefit of individuals. Examples of evolution genes acting as variation generators are found in the transposition of mobile genetic elements and in so-called site-specific recombination systems. DNA repair systems and restriction-modification systems are examples of modulators of the frequency of genetic variation. The involvement of bacterial viruses and of plasmids in DNA reshuffling and in horizontal gene transfer is a hint for their evolutionary functions. Evolution genes are thought to undergo biological evolution themselves, but natural selection for their functions is indirect, at the level of populations, and is called second-order selection. In spite of an involvement of gene products in the generation of genetic variations, evolution genes do not programmatically direct evolution towards a specific goal. Rather, a steady interplay between natural selection and mixed populations of genetic variants gives microbial evolution its direction.     

Ancient repeated sequences in the pea and mung bean genomes and implications for genome evolution

Essentially all of the sequences in the pea (Pisum sativum) genome which reassociate with single copy kinetics at standard (T_m -25°C) criterion follow repetitive kinetics at lower temperatures (about T_m-35°C). Analysis of thermal stability profiles for presumptive single copy duplexes show that they contain substantial mismatch even when formed at standard criterion. Thus most of the sequences in the pea genome which are conventionally defined as single copy are actually fossil repeats — that is, they are members of extensively diverged (mutuated) and thus presumably ancient families of repeated sequences. Coding sequences as represented by a cDNA probe prepared from poly-somal poly(A) + mRNA reassociate with single copy kinetics regardless of criterion and do not form mismatched duplexes. The coding regions thus appear to be composed of true single copy sequences but they cannot represent more than a few percent of the pea genome. Ancient diverged repeats are present, but not a prominent feature of the smaller mung bean (Vigna radiata) genome. An extension of a simple evolutionary model is proposed in which these and other differences in genome organization are considered to reflect different rates of sequence amplification or genome turnover during evolution. The model accounts for some of the differences between typical plant and animal genomes.     

Radiation: microbial evolution, ecology, and relevance to mars missions

Ultraviolet (UV) radiation has been an important environmental parameter during the evolution of life on Earth, both in its role as a mutagen and as a selective agent. This was probably especially true during the time from 3.8 to 2.5 billion years ago, when atmospheric ozone levels were less than 1% of present levels. Early Mars may not have had an "ozone shield" either, and it never developed a significant one. Even though Mars is farther away from the Sun than the Earth, a substantial surficial UV flux is present on Mars today. But organisms respond to dose rate, and on Mars, like on Earth, organisms would be exposed to diurnal variations in UV flux. Here we present data on the effect of diurnal patterns of UV flux on microbial ecosystems in nature, with an emphasis on photosynthesis and DNA synthesis effects. These results indicate that diurnal patterns of metabolism occur in nature with a dip in photosynthesis and DNA synthesis in the afternoon, in part regulated by UV flux. Thus, diurnal patterns must be studied in order to understand the effect of UV radiation in nature. The results of this work are significant to the success of human missions to Mars for several reasons. For example, human missions must include photosynthetic organisms for food production and likely oxygen production. An evolutionary approach suggests which organisms might be best suited for high UV fluxes. The diurnal aspect of these studies is critical. Terraforming is a potential goal of Mars exploration, and it will require studies of the effect of Martian UV fluxes, including their diurnal changes, on terrestrial organisms. Such studies may suggest that diurnal changes in UV only require mitigation at some times of day or year.     

An integrated haptic-enabled virtual reality system for orthognathic surgery planning

Conventional Orthognathic surgery (OGS) planning involves cephalometric analyses and dental casts to be mounted on an articulator. Dental segments are subsequently identified, cut and repositioned to allow the fabrication of intraoral wafers that guide the positioning of the osteotomy bone segments. This conventional planning introduces many inaccuracies that affect the post-surgery outcomes. Although computer technologies have advanced computational tools for OGS planning, they have failed in providing a practical solution. Many focuses only on some specific stages of the planning process, and their ability to transfer preoperative planning data to the operating room is limited. This paper proposes a new integrated haptic-enabled virtual reality (VR) system for OGS planning. The system incorporates CAD tools and haptics to facilitate a complete planning process and is able to automatically generate preoperative plans. A clinical pre-diagnosis is also provided automatically by the system based on the patient’s digital data. A functional evaluation based on a real patient case study demonstrates that the proposed virtual OGS planning method is feasible and more effective than the traditional approach at increasing the intuitiveness and reducing errors and planning times.     

Evolutionary relationships among the permease proteins of the bacterial phosphoenolpyruvate: Sugar phosphotransferase system. Construction of phylogenetic trees and possible relatedness to proteins of eukaryotic mitochondria

Summary The amino acid sequences of 15 sugar permeases of the bacterial phosphoenolpyruvatedependent phosphotransferase system (PTS) were divided into four homologous segments, and these segments were analyzed to give phylogenetic trees. The permease segments fell into four clusters: the lactose-cellobiose cluster, the fructose-mannitol cluster, the glucose-N-acetylglucosamine cluster, and the sucrose--glucoside cluster. Sequences of the glucitol and mannose permeases (clusters 5 and 6, respectively) were too dissimilar to establish homology with the other permeases, but short regions of statistically significant sequence similarities were noted. The functional and structural relationships of these permease segments are discussed.Some of the homologous PTS permeases were found to exhibit sufficient sequence similarity to subunits 4 and 5 of the eukaryotic mitochondrial NADH dehydrogenase complex to suggest homology. Moreover, subunits 4 and 5 of this complex appeared to be homologous to each other, suggesting that these PTS and mitochondrial proteins comprise a superfamily. The integral membrane subunits of the evolutionarily divergent mannose PTS permease, the P and M subunits, exhibited limited sequence similarity to subunit 6 of the mitochondrial F₁F₀-ATPase and subunit 5b of cytochrome oxidase, respectively. These results suggest that PTS sugar permeases and mitochondrial proton-translocating proteins may be related, although the possibility of convergent evolution cannot be ruled out.     

Distributed shared arrays: A distributed virtual machine with mobility support for reconfiguration

Distributed Shared Arrays (DSA) is a distributed virtual machine that supports Java-compliant multithreaded programming with mobility support for system reconfiguration in distributed environments. The DSA programming model allows programmers to explicitly control data distribution so as to take advantage of the deep memory hierarchy, while relieving them from error-prone orchestration of communication and synchronization at run-time. The DSA system is developed as an integral component of mobility support middleware for Grid computing so that DSA-based virtual machines can be reconfigured to adapt to the varying resource supplies or demand over the course of a computation. The DSA runtime system also features a directory-based cache coherence protocol in support of replication of user-defined sharing granularity and a communication proxy mechanism for reducing network contention. System reconfiguration is achieved by a DSA service migration mechanism, which moves the DSA service and residing computational agents between physical servers for load balancing and fault resilience. We demonstrate the programmability of the model in a number of parallel applications and evaluate its performance by application benchmark programs, in particular, the impact of the coherence granularity and service migration overhead. Song Fu received the BS degreee in computer science from Nanjing University of Aeronautics and Astronautics, China, in 1999, and the MS degree in computer science from Nanjing University, China, in 2002. He is currently a PhD candidate in computer engineering at Wayne State University. His research interests include the resource management, security, and mobility issues in wide-area distributed systems. Cheng-Zhong Xu received the BS and MS degrees in computer science from Nanjing University in 1986 and 1989, respectively, and the Ph.D. degree in computer science from the University of Hong Kong in 1993. He is an Associate Professor in the Department of Electrical and Computer Engineer of Wayne State University. His research interests lie in distributed are in distributed and parallel systems, particularly in resource management for high performance cluster and grid computing and scalable and secure Internet services. He has published more than100 peer-reviewed articles in journals and conference proceedings in these areas. He is the author of the book Scalable and Secure Internet Services and Architecture (CRC Press, 2005) and a co-author of the book Load Balancing in Parallel Computers: Theory and Practice (Kluwer Academic, 1997). He serves on the editorial boards of J. of Parallel and Distributed Computing, J. of Parallel, Emergent, and Distributed Systems, J. of High Performance Computing and Networking, and J. of Computers and Applications. He was the founding program co-chair of International Workshop on Security in Systems and Networks (SSN), the general co-chair of the IFIP 2006 International Conference on Embedded and Ubiquitous Computing (EUC06), and a member of the program committees of numerous conferences. His research was supported in part by the US National Science Foundation, NASA, and Cray Research. He is a recipient of the Faculty Research Award of Wayne State University in 2000, the Presidents Award for Excellence in Teaching in 2002, and the Career Development Chair Award in 2003. He is a senior member of the IEEE. Brian A. Wims was born in Washington, DC in 1967. He received the Bachelor of Science in Electrical Engineering from GMI-EMI (now called Kettering University) in 1990; and Master of Science in Computer Engineering from Wayne State University in 1999. His research interests are primarily in the fields of parallel and distributed systems with applications in Mobile Agent technologies. From 1990–2001 he worked in various Engineering positions in General Motors, including Electrical Analysis, Software Design, and Test and Development. In 2001, he joined the General Motors IS&S department where he is currently a Project Manager in the Computer Aided Test group. Responsibilities include managing the development of test automation applications in the Electrical, EMC, and Safety Labs. Ramzi Basharahil was born in Aden, Yemen in 1972. He received the Bachelor of Science degree in Electrical Engineering from the United Arab Emirates University. He graduated top of his engineering graduated class of 1997. He obtained Master of Science degree in 2001 from Wayne State University in the Department of Electrical and Computer Engineering. His main research interests are primarily in the fields of parallel and distributed systems with applications to distributed processing across cluster of servers. From 1997 to 1998, he worked as a Teaching Assistant in the Department of Electrical Engineering at the UAE University. In 2000, he joined Internet Security Systems as a security software engineer. He later joined NetIQ Corporation in 2002 and still working since then. He is leading the security events trending and events management software development where he is involved in designing and the implementing event/log managements products.     

ISMapper: identifying transposase insertion sites in bacterial genomes from short read sequence data

Background

Insertion sequences (IS) are small transposable elements, commonly found in bacterial genomes. Identifying the location of IS in bacterial genomes can be useful for a variety of purposes including epidemiological tracking and predicting antibiotic resistance. However IS are commonly present in multiple copies in a single genome, which complicates genome assembly and the identification of IS insertion sites. Here we present ISMapper, a mapping-based tool for identification of the site and orientation of IS insertions in bacterial genomes, directly from paired-end short read data.

Results

ISMapper was validated using three types of short read data: (i) simulated reads from a variety of species, (ii) Illumina reads from 5 isolates for which finished genome sequences were available for comparison, and (iii) Illumina reads from 7 Acinetobacter baumannii isolates for which predicted IS locations were tested using PCR. A total of 20 genomes, including 13 species and 32 distinct IS, were used for validation. ISMapper correctly identified 97 % of known IS insertions in the analysis of simulated reads, and 98 % in real Illumina reads. Subsampling of real Illumina reads to lower depths indicated ISMapper was able to correctly detect insertions for average genome-wide read depths >20x, although read depths >50x were required to obtain confident calls that were highly-supported by evidence from reads. All ISAba1 insertions identified by ISMapper in the A. baumannii genomes were confirmed by PCR. In each A. baumannii genome, ISMapper successfully identified an IS insertion upstream of the ampC beta-lactamase that could explain phenotypic resistance to third-generation cephalosporins. The utility of ISMapper was further demonstrated by profiling genome-wide IS6110 insertions in 138 publicly available Mycobacterium tuberculosis genomes, revealing lineage-specific insertions and multiple insertion hotspots.

Conclusions

ISMapper provides a rapid and robust method for identifying IS insertion sites directly from short read data, with a high degree of accuracy demonstrated across a wide range of bacteria.     

Microbial interactions involving sulfur bacteria: implications for the ecology and evolution of bacterial communities

A major goal of microbial ecology is the identification and characterization of those microorganisms which govern transformations in natural ecosystems. This review summarizes our present knowledge of microbial interactions in the natural sulfur cycle. Central to the discussion is the recent progress made in understanding the co-occurrence in natural ecosystems of sulfur bacteria with contrasting nutritional requirements and of the spatially very close associations of bacteria, the so-called phototrophic consortia (e.g. 'Chlorochromatium aggregatum' or 'Pelochromatium roseum'). In a similar way, microbial interactions may also be significant during microbial transformations other than the sulfur cycle in natural ecosystems, and could also explain the low culturability of bacteria from natural samples.     

Origin of microbial life hypothesis: a gel cytoplasm lacking a bilayer membrane, with infrared radiation producing exclusion zone (EZ) water, hydrogen as an energy source and thermosynthesis for bioenergetics

The hypothesis is proposed that pre-biotic bacterial cell(s) and the first cells capable of growth/division did not require a cytoplasmic membrane. A gel-like microscopic structure less than a cubic micrometer may have had a dual role as both an ancient pre-cytoplasm and a boundary layer to the higher-entropy external environment. The gel pre-cytoplasm exposed to radiant energy, especially in the infrared (IR) region of the EM spectrum resulted in the production of an exclusion zone (EZ) with a charge differential (−100 to −200 mV) and boundary that may have been a possible location for the latter organization of the first cytoplasmic membrane. Pre-biotic cells and then-living cells may have used hydrogen as the universal energy source, and thermosynthesis in their bioenergetic processes. These components will be discussed as to how they are interconnected, and their hypothesized roles in the origin of life.     

Studies on the evolution of auxin carriers and phytotropin receptors: Transmembrane auxin transport in unicellular and multicellular Chlorophyta

The characteristics of transmembrane transport of ¹⁴C-labelled indol-3yl-acetic acid ([1-¹⁴C]IAA) were compared in Chlorella vulgaris Beij., a simple unicellular green alga, and in Chara vulgaris L., a branched, multicellular green alga exhibiting axial polarity and a high degree of cell and organ specialization. In Chara thallus cells, three distinguishable trans-plasmamembrane fluxes contributed to the net uptake of [1-¹⁴C]-IAA from an external solution, viz.: a non-mediated, pH-sensitive influx of undissociated IAA (IAAH); a saturable influx of IAA; and a saturable efflux of IAA. Both saturable fluxes were competitively inhibited by unlabelled IAA. Association of [³H]IAA with microsomal preparations from Chara thallus tissue was competitively inhibited by unlabelled IAA. Results indicated that up-take carriers occurred in the membranes at a much higher density than efflux carriers. The efflux component of IAA net uptake by Chara was not affected by several phytotropins (N-1-naphthylphthalmic acid, NPA; 2-(1-pyrenoyl)benzoic acid; and 5-(2-carboxyphenyl)-3-phenylpyrazole), which are potent non-competitive inhibitors of specific auxin-efflux carriers in more advanced plant groups, and no evidence was found for a specific association of [³H]NPA with Chara microsomal preparations. It was concluded that Chara lacked phytotropin receptors. Net uptake of [1-¹⁴C]IAA also was unaffected by 2,3,5-triiodobenzoic acid except at concentrations ( 10^–1 mol · m^–3) high enough to depress cytoplasmic pH (determined by uptake of 5,5-dimethyloxazolidine-2,4-dione). Chlorella cells accumulated [1-¹⁴C]IAA from an external solution by pH-sensitive diffusion of IAA across the plasma membrane and anion (IAA^–) trapping, but no evidence was found in Chlorella for the occurrence of IAA carriers. These results indicate that carrier systems capable of mediating the transmembrane transport of auxins appeared at a very early stage in the evolution of green plants, possibly in association with the origin of a differentiated, multicellular plant body. Phytotropin receptors evolved independently of the carriers.Abbreviations CPP 5-(2-carboxyphenyl)-3-phenylpyrazole - DMO 5,5-dimethyloxazolidine-2,4-dione - IAA indol-3yl-acetic acid - NPA N-1-naphthylphthalamic acid - PBA 2-(1-pyrenoyl)benzoic acid - TIBA 2,3,5-triiodobenzoic acid We thank the Nuffield Foundation for the award of an Undergraduate Research Bursary to J.E.D.-F., Dr. G.F. Katekar, C.S.I.R.O., Canberra, Australia for generous gifts of phytotropins, and Mrs. R.P. Bell for technical support.     

The evolution of juvenile-adult interactions in populations structured in age and space

We study the evolution of a spatially structured population with two age classes using spatial moment equations. In the model, adults can either help juveniles by increasing their survival, or adopt a cannibalistic behaviour and consume juveniles. While cannibalism is the sole evolutionary outcome when the population is well-mixed, both cannibalism and parental care can be evolutionarily stable if the population is viscous. Our analysis allows us to make two main technical points. First, we present a method to define invasion fitness in class-structured viscous populations, which allows us to apply adaptive dynamics methodology. Second, we show that ordinary pair approximation introduces an important quantitative bias in the evolutionary model, even on random networks. We propose a correction to the ordinary pair approximation that yields quantitative accuracy, and discuss how the bias associated with this approach is precisely what allows us to identify subtle aspects associated with the evolutionary dynamics of spatially structured populations.     

A novel algorithm with differential evolution and coral reef optimization for extreme learning machine training

Extreme learning machine (ELM) is a novel and fast learning method to train single layer feed-forward networks. However due to the demand for larger number of hidden neurons, the prediction speed of ELM is not fast enough. An evolutionary based ELM with differential evolution (DE) has been proposed to reduce the prediction time of original ELM. But it may still get stuck at local optima. In this paper, a novel algorithm hybridizing DE and metaheuristic coral reef optimization (CRO), which is called differential evolution coral reef optimization (DECRO), is proposed to balance the explorative power and exploitive power to reach better performance. The thought and the implement of DECRO algorithm are discussed in this article with detail. DE, CRO and DECRO are applied to ELM training respectively. Experimental results show that DECRO-ELM can reduce the prediction time of original ELM, and obtain better performance for training ELM than both DE and CRO.     

The curse of the pharaoh in space: free-living infectious stages and the evolution of virulence in spatially explicit populations

The idea that parasites with long-lived infective stages may evolve higher virulence has received considerable attention. This idea is called 'the curse of the pharaoh' because of the hypothesis that the death of Lord Carnavon was caused by very long-lived propagules of a highly virulent infectious disease. Here, we examined the evolution of diseases that transmit via free-living stages in a spatial context. We show that, if virulence evolves independently of transmission, long-lived infective stages can select for higher virulence. There is always the evolution of a finite transmission rate, which becomes higher when the infective stages are shorter lived. When a trade-off occurs between transmission and virulence, we show that there is no evidence for the curse of the pharaoh. Indeed, higher transmission and therefore virulence may be selected for by shorter rather than long-lived infective stages.     

The role of trade-off shapes in the evolution of parasites in spatial host populations: an approximate analytical approach

Given the substantial changes in mixing in many populations, there is considerable interest in the role that spatial structure can play in the evolution of disease. Here we examine the role of different trade-off shapes in the evolution of parasites in a spatially structured host population where infection can occur locally or globally. We develop an approximate adaptive dynamic analytical approach, to examine how the evolutionarily stable (ES) virulence depends not only on the fraction of global infection/transmission but also on the shape of the trade-off between transmission and virulence. Our analysis can successfully predict the ES virulence found previously by simulation of the full system. The analysis confirms that when there is a linear trade-off between transmission and virulence spatial structure may lead to an ES virulence that increases as the proportion of global transmission increases. However, we also show that the ESS disappears above a threshold level of global infection, leading to maximization. In addition just below this threshold, there is the possibility of evolutionary bi-stabilities. When we assume the realistic trade-off between transmission and virulence that results in an ESS in the classical mixed model, we find that spatial structure can increase or decrease the ES virulence. A relatively high proportion of local infection reduces virulence but intermediate levels can select for higher virulence. Our work not only emphasizes the importance of spatial structure to the evolution of parasites, but also makes it clear that situations between the local and the global need to be considered. We also emphasize the key role that the shape of trade-offs plays in evolutionary outcomes.     

Comprehensive analysis of glycosyltransferases in eukaryotic genomes for structural and functional characterization of glycans

Glycosyltransferases comprise highly divergent groups of enzymes, which play a central role in the synthesis of complex glycans. Because the repertoire of glycosyltransferases in the genome determines the range of synthesizable glycans, and because the increasing amount of genome sequence data is now available, it is essential to examine these enzymes across organisms to explore possible structures and functions of the glycoconjugates. In this study, we systematically investigated 36 eukaryotic genomes and obtained 3426 glycosyltransferase homologs for biosynthesis of major glycans, classified into 53 families based on sequence similarity. The families were further grouped into six functional categories based on the biosynthetic pathways, which revealed characteristic patterns among organism groups in the degree of conservation and in the number of paralogs. The results also revealed a strong correlation between the number of glycosyltransferases and the number of coding genes in each genome. We then predicted the ability to synthesize major glycan structures including N-glycan precursors and GPI-anchors in each organism from the combination of the glycosyltransferase families. This indicates that not only parasitic protists but also some algae are likely to synthesize smaller structures than the structures known to be conserved among a wide range of eukaryotes. Finally we discuss the functions of two large families, sialyltransferases and β4-glycosyltransferases, by performing finer classifications into subfamilies. Our findings suggest that universality and diversity of glycans originate from two types of evolution of glycosyltransferase families, namely conserved families with few paralogs and diverged families with many paralogs.     

Lateral gene transfer, lineage-specific gene expansion and the evolution of Nucleo Cytoplasmic Large DNA viruses

Nucleo Cytoplasmic Large DNA viruses (NCLDVs) are a diverse group that infects a wide range of eukaryotic hosts (for example, vertebrates, insects, protists,…) and also show a huge range in genome size (between 100 kb and 1.2 Mb). Here I review some recent results that shed light on the origin and genome evolution of these viruses. Current data suggests that NCLDVs could have originated from a simple and ancient viral ancestor with a small subset of 30-35 genes encoding replication and structural proteins. Subsequent lateral gene transfer of both cellular genes and diverse families of Mobile Genetic Elements, followed by massive lineage-specific gene duplications is probably responsible for the huge diversity of genome size and composition found in extant NCLDVs.     

The source of the heat resistance of bacterial spores: Study of water in spores by NMR

It has been postulated that the heat stabilization of the essential macromolecules in the core of the spore may be produced by dehydration at two levels: (i) the spore is drier at high relative humidity than the vegetative cell and (ii) the core of the spore may be less hydrated than the cortex and the coat. The latter postulate was subjected to experimental testing by ¹H-NMR studies of the water signal in the five species of spores and coat and (coat + cortex) preparations. The transverse relaxation rate $\text{(}\text{1}\text{T}{}_2\text{)}$ was determined in samples equilibrated at constant relative humidity. To allow for the effect of paramagnetic ions on $\text{1}\text{T}{}_2$ a model system (wool keratin) was studied in the presence of known amounts of Ca(II), Mn(II), Cu(II), Ni(II) and Fe(III). Because of the dominant effect of Mn(II) on $\text{1}\text{T}{}_2$, the effect of small amounts of other metal ions in spores was neglected. The relaxation rate of water at a particular relative humidity and manganese concentration was consistently less for intact spores than for coat or coat + cortex, hence the water in the core is more mobile than in the outer integuments. Sorption isotherm studies have shown that at a particular relative humidity there is about as much water in the core as in the cortex and coat. These two results taken together indicate that the hypothesis that the core is drier than the cortex and coat is incorrect, hence the spore is not heat-stabilized in this way. A theory is proposed in which heat stabilization is attributed to immobilization of essential enzymes and nuclei acids by a solid support, calcium dipicolinate, in a similar fashion to the heat stabilization of enzymes in a charged polymer matrix. It is proposed that stabilization is effected by electrostatic and hydrogen bonds between the calcium dipicolinate and the essential macromolecules. Experiments in progress show that enzymes and DNA are heat-stabilized in vitro by calcium dipicolinate.