The effects of mulching and abandonment on the viability of the perennial grassland species Plantago lanceolata

Abandonment and fragmentation are the primary causes of decline for many light-demanding grassland species in the modern agricultural landscape. In order to maintain a flora rich in such species, design of management practices based upon knowledge of life-history consequences following management shifts is essential. In this study, we investigated the demography of the perennial grassland species Plantago lanceolata for 4 years in one mulched site and two abandoned sites to compare how the two treatments influenced population dynamics. Compared to abandonment, mulching had a small but positive effect on the population growth rate (λ) of P. lanceolata. In both the mulched and the abandoned sites, growth and stasis among the largest plants contributed most strongly to λ, while the contribution of fecundity was negligible in both treatments. λ of P. lanceolata varied more between years than between treatments, most notably because λ values below unity were observed in the abandoned sites in a 1-year period that included a severe winter. The population of the mulched site consisted of larger ramets and had higher clonal growth rates than the populations of the abandoned sites. This explains the apparently higher resilience to unfavorable climatic conditions in the mulched site. We conclude that management by mulching is better than abandonment for the long-term persistence of P. lanceolata. However, due to low recruitment also in the mulched site, even mulching may be insufficient for P. lanceolata to persist over long time periods.     

Electrogenetic signaling and information propagation for controlling microbial consortia via programmed lysis

To probe signal propagation and genetic actuation in microbial consortia, we have coopted the components of both redox and quorum sensing (QS) signaling into a communication network for guiding composition by “programming” cell lysis. Here, we use an electrode to generate hydrogen peroxide as a redox cue that determines consortia composition. The oxidative stress regulon of Escherichia coli, OxyR, is employed to receive and transform this signal into a QS signal that coordinates the lysis of a subpopulation of cells. We examine a suite of information transfer modalities including “monoculture” and “transmitter-receiver” models, as well as a series of genetic circuits that introduce time-delays for altering information relay, thereby expanding design space. A simple mathematical model aids in developing communication schemes that accommodate the transient nature of redox signals and the “collective” attributes of QS signals. We suggest this platform methodology will be useful in understanding and controlling synthetic microbial consortia for a variety of applications, including biomanufacturing and biocontainment.     

Investigation of the metabolic pattern in maple syrup urine disease by means of glass capillary gas chromatography and mass spectrometry

Urine and serum from patients with maple syrup urine disease (MSUD) have been examined quantitatively and qualitatively using glass capillary gas chromatography in combination with mass spectrometry. During clinical episodes, patients with this disease were found to excrete increased amounts of the following metabolites in addition to the previously recognized branched-chain 2-keto and 2-hydroxy acids, lactate and 3-hydroxybutyrate; 2-hydroxybutyrate, 2-hydroxyisobutyrate, 3-hydroxyisovalerate, 3-hydroxylsobutyrate and 2-methyl-3-hydroxybutyrate. Most of the latter compounds seem to accompany ketoacidosis and lactic acidosis. The capillary column also separated the d- and l-forms of 2-keto-3-methylvalerate, and both isomers were, in contrast to earlier assumptions, present in the MSUD patients. The results clearly demonstrate that new information on the metabolic situation in well known disorders may be obtained by exploiting the high resolving power of capillary columns.     

Elevated serum MMP-9/TIMP-1 ratio in patients with homozygous familial hypercholesterolemia: Effects of LDL-apheresis

ObjectiveMatrix degradation within an atherosclerotic plaque is an important pathogenic factor in atherosclerosis, and is largely modulated by the balance between matrix metalloproteinases (MMPs) and their endogenous inhibitors (i.e., tissue inhibitor of MMPs [TIMPs]). Familial hypercholesterolemia (FH) is a rare inherited disorder associated with premature coronary heart disease. The aim of the present study was to examine MMP-9 and TIMP-1 on plasma and cellular mRNA levels in homozygous FH patients (n = 7) compared with age- and sex-matched heterozygous FH patients (n = 6), and with healthy subjects (n = 7), and to test whether once-weekly LDL-apheresis (three consecutive sessions) of homozygous FH patients show short-term effects on these variables.ResultsThe main findings were that (i) Compared to healthy control subjects, homozygous FH patients have significantly higher serum levels of MMP-9 and lower levels of TIMP-1, and consequently significantly higher MMP-9/TIMP-1 ratio, potentially reflecting higher MMP-9 activity. (ii) Peripheral blood mononuclear cells (PBMC) isolated from FH homozygotes have significantly higher mRNA levels of MMP-9 compared to cells from heterozygotes. (iii) TNFα-stimulated PBMC from FH homozygotes released borderline-significantly more MMP-9 than cells from heterozygotes and healthy controls. (iv) LDL-apheresis (one day before treatment versus fifteen days later, on the day after the weekly treatment) had no significant short-term effect on any of the MMP-9 and TIMP-1 variables measured in serum and cells.ConclusionsThe data may suggest that homozygous FH patients have an enhanced matrix degrading potential as compared with heterozygous FH patients and healthy controls, potentially contributing to the increased cardiovascular risk observed in these patients.     

The role of parasites in the dynamics of a reindeer population

Even though theoretical models show that parasites may regulate host population densities, few empirical studies have given support to this hypothesis. We present experimental and observational evidence for a host-parasite interaction where the parasite has sufficient impact on host population dynamics for regulation to occur. During a six year study of the Svalbard reindeer and its parasitic gastrointestinal nematode Ostertagia gruehneri we found that anthelminthic treatment in April-May increased the probability of a reindeer having a calf in the next year, compared with untreated controls. However, treatment did not influence the over-winter survival of the reindeer. The annual variation in the degree to which parasites depressed fecundity was positively related to the abundance of O. gruehneri infection the previous October, which in turn was related to host density two years earlier. In addition to the treatment effect, there was a strong negative effect of winter precipitation on the probability of female reindeer having a calf. A simple matrix model was parameterized using estimates from our experimental and observational data. This model shows that the parasite-mediated effect on fecundity was sufficient to regulate reindeer densities around observed host densities.     

Neurogenic differentiation of murine and human adipose-derived stromal cells

The identification of cells capable of neuronal differentiation has great potential for cellular therapies. We examined whether murine and human adipose-derived adult stem (ADAS) cells can be induced to undergo neuronal differentiation. We isolated ADAS cells from the adipose tissue of adult BalbC mice or from human liposuction tissue and induced neuronal differentiation with valproic acid, butylated hydroxyanisole, insulin, and hydrocortisone. As early as 1-3 h after neuronal induction, the phenotype of ADAS cells changed towards neuronal morphology. Following neuronal induction, muADAS cells displayed immunocytochemical staining for GFAP, nestin and NeuN and huADAS cells displayed staining for intermediate filament M, nestin, and NeuN. Following neuronal induction of murine and human ADAS cells, Western blot analysis confirmed GFAP, nestin, and NeuN protein expression. Pretreatment with EGF and basic FGF augmented the neuronal differentiation of huADAS cells. The neuronal differentiation of stromal cells from adipose tissue has broad biological and clinical implications.     

Species composition,abundance, habitat requirements and regional distribution of terrestrial gastropods in Arctic Norway

Summary The species composition, abundance and habitat distributions of the terrestrial gastropods at lat. 70° N in Finnmark county, northern Norway were studied. Within an area with bedrocks of sandstone there were few snail species and abundance was low. Calciumrich bogs and birch woods with a luxuriant undergrowth had a richer gastropod fauna both in number of species and abundance. The snail fauna consisted of a mixture of stenoecious, calciphile species (Columella columella, Vertigo genesii, V. modesta) and very euryoecious species, e.g., Discus ruderatus, Vitrina pellucida. Cochlicopa lubrica and Nesovitrea hammonis were found only in moist, rather eutropic habitats and seemed to be more stenoecious than further south in their geographical range. There were few snails within the study area (16 species) compared with >30 species found in the coastal areas of northern Norway (Troms county) at the same latitude. This difference in the faunal composition coincides with regional divisions based on the vegetation, and may indicate a general difference in the biota of oceanic and continental areas of northern Norway. The changes in snail fauna along a coast-inland transect at about lat. 70° N are similar to those occurring along a vertical gradient in the inner fjord districts of Western Norway. It is suggested that low temperatures during the coldest part of the year are responsible for this common change in the species composition.     

Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes

The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.     

Ontogenesis of physiological responsiveness and guanine nucleotide sensitivity of cardiac muscarinic receptors during chick embryonic development

Atria isolated from 4-day chick embryos were much less responsive to the negative chronotropic effect of muscarinic agonists than were atria from 5- or 8-day embryos, even though the density of muscarinic acetylcholine receptors (mAChR) was similar at all these ages. The mAChR in hearts from 4-day embryos were also significantly less susceptible to regulation of receptor number by in vivo agonist treatment and required a 2-5-fold greater dose of the muscarinic agonist carbachol to achieve a decrease in receptor number equivalent to that observed in 5- or 8-day embryonic hearts. When 4-day atrial membranes were assayed in physiological buffers, agonist binding to the mAChR was not regulated by GTP unless a sulfhydryl reducing agent was present. Receptors from 5- and 8-day embryos did not require addition of a sulfhydryl reducing agent in order to see guanine nucleotide effects on agonist binding. Even in the presence of a sulfhydryl reducing agent, carbachol binding to the mAChR in 4-day membranes was much less sensitive to guanyl-5'-yl imidodiphosphate (GppNHp) than binding to mAChR in 5- or 8-day membranes. In addition, forskolin-activated adenylate cyclase activity was much less sensitive to inhibition by GppNHp in membranes from 4-day atria than from 5- and 8-day atria. The GTP-binding component (NI) which couples the mAChR to inhibition of adenylate cyclase activity was examined by covalent modification with pertussis toxin.(ABSTRACT TRUNCATED AT 250 WORDS)