Starvation-survival of deep subsurface isolates

Six deep, subsurface endolithic isolates were subjected to starvation conditions for up to 100 days in artificial pore water, formulated to mimic in situ geochemical conditions in the nearly saturated rock. Most isolates demonstrated the typical starvation-survival curve for chemoheterotrophic bacteria, and all became miniaturized during starvation. Starvation indices were developed to compare changes in viable cell counts between isolates. Two isolates retained higher viability after 100 days of starvation-survival. High survival correlated with sustained respiration, measured by iodonitrotetrazolium-formazan production, during starvation. In all but one case, isolates plated on two nutritionally dilute media, metal-containing and antibioticcontaining media, showed similar viable counts.     

Influence of the interleukin-6 -174 G/C gene polymorphism on exercise training-induced changes in glucose tolerance indexes.

A polymorphism in the IL-6 gene, a G-to-C substitution 176 bp upstream of the ATG translation initiation site, has been associated with diabetes prevalence and insulin resistance. Interventions including exercise training are frequently used to modify cardiovascular disease risk factors. Consequently, this project examined associations between the IL-6 -174 genotype and oral glucose tolerance test outcomes in 50- to 75-yr-old sedentary men and postmenopausal women before and after aerobic exercise training. Among the 87 individuals who started the study, 56 were retested after 6 mo of aerobic exercise training. Subject characteristics at baseline did not differ between the IL-6 genotype groups with the exception of fasting glucose, which was higher (P = 0.02, covariates age, gender, and ethnicity) in the CC genotype group. The training-induced change in glucose area under the curve during the oral glucose tolerance test varied between the IL-6 -174 genotype groups (P = 0.05, covariates age, gender, ethnicity, baseline glucose area under the curve, and percent body fat change) with a significant decrease occurring only in the GG genotype group. Insulin outcomes did not differ among the groups at baseline or after training. Training-induced changes in weight, percent body fat, maximal oxygen consumption, fasting glucose, and an insulin sensitivity index also changed similarly among the genotype groups. In conclusion, fasting glucose and the extent to which glucose tolerance changes with exercise training may be influenced by the IL-6 -174 gene polymorphism.     

Molecular Phenotyping of Immune Cells from Young NOD Mice Reveals Abnormal Metabolic Pathways in the Early Induction Phase of Autoimmune Diabetes

Islet leukocytic infiltration (insulitis) is first obvious at around 4 weeks of age in the NOD mouse – a model for human type 1 diabetes (T1D). The molecular events that lead to insulitis and initiate autoimmune diabetes are poorly understood. Since TID is caused by numerous genes, we hypothesized that multiple molecular pathways are altered and interact to initiate this disease. We evaluated the molecular phenotype (mRNA and protein expression) and molecular networks of ex vivo unfractionated spleen leukocytes from 2 and 4 week-old NOD mice in comparison to two control strains. Analysis of the global gene expression profiles and hierarchical clustering revealed that the majority (∼90%) of the differentially expressed genes in NOD mice were repressed. Furthermore, analysis using a modern suite of multiple bioinformatics approaches identified abnormal molecular pathways that can be divided broadly into 2 categories: metabolic pathways, which were predominant at 2 weeks, and immune response pathways, which were predominant at 4 weeks. Network analysis by Ingenuity pathway analysis identified key genes/molecules that may play a role in regulating these pathways. These included five that were common to both ages (TNF, HNF4A, IL15, Progesterone, and YWHAZ), and others that were unique to 2 weeks (e.g. MYC/MYCN, TGFB1, and IL2) and to 4 weeks (e.g. IFNG, beta-estradiol, p53, NFKB, AKT, PRKCA, IL12, and HLA-C). Based on the literature, genes that may play a role in regulating metabolic pathways at 2 weeks include Myc and HNF4A, and at 4 weeks, beta-estradiol, p53, Akt, HNF4A and AR. Our data suggest that abnormalities in regulation of metabolic pathways in the immune cells of young NOD mice lead to abnormalities in the immune response pathways and as such may play a role in the initiation of autoimmune diabetes. Thus, targeting metabolism may provide novel approaches to preventing and/or treating autoimmune diabetes.     

Unresponsive, a new behavioral mutant in Xenopus laevis

Abstract. A new recessive nonlethal behavioral mutant, unresponsive (ur), was recovered from a wild-caught Xenopus laevis female by gynogenesis and inbreeding. Mutant embryos do not move until they are three days old, just before feeding begins, in contrast to normal embryos which begin movements at one day, during tailbud stage. Recovery of mutant embryos is complete but slow, requiring another nine days. Grafting analysis suggests that sensory neuron function is normal in homozygous mutant embryos, but that both motorneurons and their target muscles derived from somites are affected by the mutation. Either muscle or motorneurons of unresponsive embryos can participate in normal movements during early development, prior to the stage at which intact mutant embryos recover, in chimerae with normal tissue. Failure of mutant muscle to respond normally to acetylcholine, along with the behavior of chimerae, suggests that mutant embryos do not move because they do not form functional neuromuscular junctions during early development and that the component process of neuromuscular junction formation affected by this mutation is normally performed by both nerve and muscle. during embryogenesis due to a defect in the muscle cells [5]. Armstrong and collaborators [I] have used the immobile mutant to demonstrate that the cholinergic stimulation- induced loss of gap junctions during development does not depend on muscle contraction. In this report, we examine a new mutant of Xenopus laevis, unresponsive (ur), which does not move voluntarily or in response to stimulation until just prior to the feeding stage, after which it recovers.     

On the question of natural hybridization between Pinus discolor and Pinus cembrides

Sixty Pinus cembroides and P. discolor trees from two mixed stands and eight pure stands were analysed for the composition of their wood monoterpenes, number of abaxial and adaxial stomatal rows and the number of needles per fascicle. While by far the majority of the characters analysed showed highly significant differences between the two species, only the sum of thujene, sabinene, γ-terpenene, terpinolene and p-cymene percentages, the sum of myrcene and cis-ocimene percentages, the number of abaxial stomatal rows, and the number of needles per fascicle could be used to evaluate the potential intermediacy of trees from the common sites. The results indicated the absence of any hybridization in the Sierra de la Catarina Mountains of Chihuathua (Mexico) and either a possible minute introgression of P. cembroides into P. discolor in the San Miguelito Mountains of San Luis Potosi (Mexico) or a slightly different genetic composition of the trees from this site. The results strongly support the proposal of Bailey and Hawksworth to regard P. discolor as a distinct species.     

A mathematical analysis of human leukocyte antigen serology

This paper presents and explores a comprehensive mathematical model for human leukocyte antigen serology, based on a mathematical formalization of the concept of specificity. This model is general enough to take into account such factors as absorption, elution, cross-reactivity, and incomplete immunization. The paper includes a presentation of the relevant immunological background and a short discussion of the underlying computational difficulty of the basic problems. Upper and lower bounds are derived for the minimal number of specificities required to explain a given set of HLA reactions, and it is shown that the numbers of antibodies and antigens involved must be no less then this minimal number of specificities. Other techniques and theorems are also presented to aid in reducing and analyzing HLA reaction matrices.     

Relating fish biomass to habitat and chemistry in headwater streams of the northeastern United States

Stream pH and stream habitat have both been identified as important environmental features influencing total fish biomass in streams, but few studies have evaluated the relative influence of habitat and pH together. We measured total fish biomass, stream habitat, and stream pH in sixteen sites from three tributary systems in the northeastern United States. The habitat metrics included total pool area, a cover score, large wood frequency, and stream temperature. We created and compared nine linear models relating total fish biomass in summer to stream pH and stream habitat using Akaike’s Information Criterion (AIC) analysis. The best (most parsimonious) models included pool area and stream pH. These results and a separate comparison of three regressions (low-flow pH, pool area, and these two metrics together versus total fish biomass) suggest that both habitat and stream buffering capacity affect the total biomass of fish in northeastern US headwater streams. When stream pH is adequate (low-flow pH greater than at least 5.7), physical habitat is likely to be more important, but under lower pH conditions, habitat is likely to be less effective in accounting for the total biomass of fish in these streams. This work demonstrates the continued effects of stream acidification in the northeastern US and more generally, it illustrates the importance of considering both physical and chemical conditions of a stream when evaluating the factors influencing fish communities.     

A POPULATION STUDY OF CHARA ZEYLANICA IN TEXAS,OKLAHOMA, AND NEW MEXICO

Examination of 140 collections of Chara zeylanica from 3 southwestern states shows that a strong dichotomy exists in the collections. Some produce 4-plated antheridia while others produce 8-plated antheridia. Absolute separation of the study material is possible on the basis of plate number. In addition, 3 other characters (length/width ratio of oospores; fertility of first branchlet node; and number of distal ecorticate branchlet internodes) show strong correlation with the antheridial type. Preliminary chromosomal work indicates that a segregation at this level may also be possible. In 4-plated collections examined, n = 28; 8-plated collections are usually n = 56; however, a few 8-plated collections are n = 42. No conclusion has been reached regarding the status of the latter collections.     

Metal Resistance and Lithoautotrophy in the Extreme Thermoacidophile Metallosphaera sedula

Archaea such as Metallosphaera sedula are thermophilic lithoautotrophs that occupy unusually acidic and metal-rich environments. These traits are thought to underlie their industrial importance for bioleaching of base and precious metals. In this study, a genetic approach was taken to investigate the specific relationship between metal resistance and lithoautotrophy during biotransformation of the primary copper ore, chalcopyrite (CuFeS₂). In this study, a genetic system was developed for M. sedula to investigate parameters that limit bioleaching of chalcopyrite. The functional role of the M. sedula copRTA operon was demonstrated by cross-species complementation of a copper-sensitive Sulfolobus solfataricus copR mutant. Inactivation of the gene encoding the M. sedula copper efflux protein, copA, using targeted recombination compromised metal resistance and eliminated chalcopyrite bioleaching. In contrast, a spontaneous M. sedula mutant (CuR1) with elevated metal resistance transformed chalcopyrite at an accelerated rate without affecting chemoheterotrophic growth. Proteomic analysis of CuR1 identified pleiotropic changes, including altered abundance of transport proteins having AAA-ATPase motifs. Addition of the insoluble carbonate mineral witherite (BaCO₃) further stimulated chalcopyrite lithotrophy, indicating that carbon was a limiting factor. Since both mineral types were actively colonized, enhanced metal leaching may arise from the cooperative exchange of energy and carbon between surface-adhered populations. Genetic approaches provide a new means of improving the efficiency of metal bioleaching by enhancing the mechanistic understanding of thermophilic lithoautotrophy.