Summary
Collections of micro‐organisms are a crucial element of life science research infrastructure but are vulnerable to loss and damage caused by natural or man‐made disasters, the untimely death ...or retirement of personnel, or the loss of research funding. Preservation of biological collections has risen in priority due to a new appreciation for discoveries linked to preserved specimens, emerging hurdles to international collecting and decreased funding for new collecting. While many historic collections have been lost, several have been preserved, some with dramatic rescue stories. Rescued microbes have been used for discoveries in areas of health, biotechnology and basic life science. Suggestions for long‐term planning for microbial stocks are listed, as well as inducements for long‐term preservation.
Microbes produce an extraordinary array of microbial defense systems. These
include classical antibiotics, metabolic by-products, lytic agents, numerous
types of protein exotoxins, and bacteriocins. ...The abundance and diversity of
this potent arsenal of weapons are clear. Less clear are their evolutionary
origins and the role they play in mediating microbial interactions. The goal of
this review is to explore what we know about the evolution and ecology of the
most abundant and diverse family of microbial defense systems: the
bacteriocins. We summarize current knowledge of how such extraordinary protein
diversity arose and is maintained in microbial populations and what role these
toxins play in mediating microbial population-level and community-level
dynamics. In the latter half of this review we focus on the potential role
bacteriocins may play in addressing human health concerns and the current role
they serve in food preservation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
3.
Antibody Repertoire Development in Swine Butler, J.E; Wertz, Nancy; Sinkora, Marek
Annual review of animal biosciences,
02/2017, Letnik:
5, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We describe the domestication of the species, explore its value to agriculture and bioscience, and compare its immunoglobulin (Ig) genes to those of other vertebrates. For encyclopedic information, ...we cite earlier reviews and chapters. We provide current gene maps for the heavy and light chain loci and describe their polygeny and polymorphy. B-cell and antibody repertoire development is a major focus, and we present findings that challenge several mouse-centric paradigms. We focus special attention on the role of ileal Peyer's patches, the largest secondary lymphoid tissues in newborn piglets and a feature of all artiodactyls. We believe swine fetal development and early class switch evolved to provide natural secretory IgA antibodies able to prevent translocation of bacteria from the gut while the bacterial PAMPs drive development of adaptive immunity. We discuss the value of using the isolator piglet model to address these issues.
Accurately estimating the mean size of features within an opaque material using only 2D observations is a common requirement in the materials and medical communities. Attempting to employ numerical ...methods to obtain an accurate estimate of the full 3D size distribution, which is often important for calculating structure-dependent material properties, is substantially more challenging. This paper circumvents the error propagation issues observed with classical numerical approaches, such as those formulated by Saltikov, Johnson, and Schwartz, through comparison of two calculation methods: (i) the direct simulation of synthetic particles and (ii) inversion of the conventional Saltikov analysis. Each method was used to generate dispersions whose 3D particle diameters followed lognormal distributions of varying shape parameters; the mean and variance were then predicted for 2D cross-sectional measurements. Parameters from both the 2D and 3D distributions were analytically coupled to produce a set of equations for accurately transforming cross-sectional observations into estimates of the full 3D distributions. Accuracy of the 2D-to-3D transformation is, for the first time, characterized as a function of the population size and measurement resolution. Specifically, included figures allow for rapid conversion from 2D to 3D metrics with the corresponding margin of error. The Inverse Saltikov method is shown to provide superior transformation accuracy for the idealized cases of lognormally distributed and randomly dispersed spherical particles when compared to either the Direct Simulation method or classical numerical approaches.
Swine share with most placental mammals the same five antibody isotypes and same two light chain types. Loci encoding λ, κ and Ig heavy chains appear to be organized as they are in other mammals. ...Swine differ from rodents and primates, but are similar to rabbits in using a single VH family (VH3) to encode their variable heavy chain domain, but not the family used by cattle, another artiodactyl. Distinct from other hoofed mammals and rodents, Cκ:Cλ usage resembles the 1:1 ratio seen in primates. Since IgG subclasses diversified after speciation, same name subclass homologs do not exist among swine and other mammals unless very closely related. Swine possess six putative IgG subclasses that appear to have diversified by gene duplication and exon shuffle while retaining motifs that can bind to FcγRs, FcRn, C1q, protein A and protein G. The epithelial chorial placenta of swine and the precosial nature of their offspring have made piglets excellent models for studies on fetal antibody repertoire development and on the postnatal role of gut colonization, maternal colostrum and neonatal infection on the development of adaptive immunity during the “critical window” of immunological development. This chapter traces the study of the humoral immune system of this species through its various eras of discovery and compiles the results in tables and figures that should be a useful reference for educators and investigators.
Heteroepitaxial recrystallization (HeRX) is a recently discovered recrystallization mechanism that can occur during thermomechanical processing of Ni-base superalloys. It is important to understand ...this mechanism because it offers insights into grain size control, which is critical to the tensile, fatigue, and creep properties of superalloys. In this paper, HeRX activity in the low solvus high refractory (LSHR) is quantitatively characterized using combined energy-dispersive X-ray spectroscopy and electron backscatter diffraction. The formation of heteroepitaxially recrystallized grains is observed within the intermediate-misfit γ–γ′ superalloy LSHR; this suggests the HeRX is more widespread than initially thought. Microstructural imaging indicates that the presence of a coherent γ shell formed via inverse precipitation is not a necessary condition for the nucleation of HeRX grains. HeRX grains are found to comprise the large grain tail of the grain size distribution, regardless of processing condition. The extent of HeRX grain formation and growth in LSHR is determined as a function of strain, forging rate, and thermal history.
This study examines the generalized multiquadrics (MQ), φ
j
(x) = (x−x
j
)
2+
c
j
2
β in the numerical solutions of elliptic two-dimensional partial differential equations (PDEs) with Dirichlet ...boundary conditions. The exponent β as well as
c
j
2 can be classified as shape parameters since these affect the shape of the MQ basis function. We examined variations of β as well as
c
j
2 where
c
j
2 can be different over the interior and on the boundary. The results show that increasing ,β has the most important effect on convergence, followed next by distinct sets of (
c
j
2)Ω∂Ω ≪ (
c
j
2)∂Ω. Additional convergence accelerations were obtained by permitting both (
c
j
2)Ω∂Ω and (
c
j
2)∂Ω to oscillate about its mean value with amplitude of approximately 1/2 for odd and even values of the indices. Our results show high orders of accuracy as the number of data centers increases with some simple heuristics.
The ability to identify factors responsible for disease in all species depends on the ability to separate those factors which are environmental from those that are intrinsic. This is particularly ...important for studies on the development of the adaptive immune response of neonates. Studies on laboratory rodents or primates have been ambiguous because neither the effect of environmental nor maternal factors on the newborn can be controlled in mammals that: (i) transmit potential maternal immunoregulatory factors in utero and (ii) are altricial and cannot be reared after birth without their mothers. Employing the newborn piglet model can address each of these concerns. However, it comes at the price of having first to characterize the immune system of swine and its development. This review focuses on the porcine B cell system, especially on the methods used for its characterization in fetal studies and neonatal piglets. Understanding these procedures is important in the interpretation of the data obtained. Studies on neonatal piglets have (a) provided valuable information on the development of the adaptive immune system, (b) lead to important advances in evolutionary biology, (c) aided our understanding of passive immunity and (d) provided opportunities to use swine to address specific issues in veterinary and biomedical research and immunotherapy. This review summarizes the history of the development of the piglet as a model for antibody repertoire development, thus providing a framework to guide future investigators.
Eleven genomic porcine Cγ gene sequences are described that represent six putative subclasses that appear to have originated by gene duplication and exon shuffle. The genes previously described as ...encoding porcine IgG1 and IgG3 were shown to be the IgG1a and IgG1b allelic variants of the IGHG1 gene, IgG2a and IgG2b are allelic variants of the IGHG2 gene, while “new” IgG3 is monomorphic, has an extended hinge, is structurally unique, and appears to encode the most evolutionarily conserved porcine IgG. IgG5b differs most from its putative allele, and its CH1 domain shares sequence homology with the CH1 of IgG3. Four animals were identified that lacked either IgG4 or IgG6. Alternative splice variants were also recovered, some lacking the CH1 domain and potentially encoding heavy chain only antibodies. Potentially, swine can transcribe >20 different Cγ chains. A comparison of mammalian Cγ gene sequences revealed that IgG diversified into subclasses after speciation. Thus, the effector functions for the IgG subclasses of each species should not be extrapolated from “same name subclasses” in other species. Sequence analysis identified motifs likely to interact with Fcγ receptors, FcRn, protein A, protein G, and C1q. These revealed IgG3 to be most likely to activate complement and bind FcγRs. All except IgG5a and IgG6a should bind to FcγRs, while all except IgG6a and the putative IgG5 subclass proteins should bind well to porcine FcRn, protein A, and protein G.
PDF
