The molecular structure and multifunctionality of the cryptic plant polymer suberin.

Suberin, a plant polyester, consists of polyfunctional long-chain fatty acids and glycerol and is an intriguing candidate as a novel antimicrobial material. We purified suberin from cork using ionic-liquid catalysis during which the glycerol bonds that ensure the polymeric nature of suberin remained intact or were only partially cleaved-yielding the closest to a native configuration reported to date. The chemistry of suberin, both in situ (in cryogenically ground cork) and ex situ (ionic-liquid extracted), was elucidated using high-resolution one- and two-dimensional solution-state NMR analyses. Centrifugation was used to isolate suberin particles of distinct densities and their monomeric composition, assembly, and bactericidal effect, inter alia, were assessed. Analysis of the molecular structure of suberin revealed the relative abundance of linear aliphatic vs. acylglycerol esters, comprising all acylglycerol configurations and the amounts of total carbonyls (C[bond, double bond]O), free acid end groups (COOH), OH aliphatics, and OH aromatics. Suberin centrifuged fractions revealed generic physiochemical properties and monomeric composition â€‹and self-assemble into polygonal structures that display distinct degrees of compactness when lyophilized. Suberin particles-suberinsomes-display bactericidal activity against major human pathogenic bacteria. Fingerprinting the multifunctionality of complex (plant) polyesters such as suberin allows for the identification of novel polymer assemblies with significant value-added properties.

Uncertainty in the response of terrestrial carbon sink to environmental drivers undermines carbon-climate feedback predictions.

Terrestrial ecosystems play a vital role in regulating the accumulation of carbon (C) in the atmosphere. Understanding the factors controlling land C uptake is critical for reducing uncertainties in projections of future climate. The relative importance of changing climate, rising atmospheric CO2, and other factors, however, remains unclear despite decades of research. Here, we use an ensemble of land models to show that models disagree on the primary driver of cumulative C uptake for 85% of vegetated land area. Disagreement is largest in model sensitivity to rising atmospheric CO2 which shows almost twice the variability in cumulative land uptake since 1901 (1 s.d. of 212.8 PgC vs. 138.5 PgC, respectively). We find that variability in CO2 and temperature sensitivity is attributable, in part, to their compensatory effects on C uptake, whereby comparable estimates of C uptake can arise by invoking different sensitivities to key environmental conditions. Conversely, divergent estimates of C uptake can occur despite being based on the same environmental sensitivities. Together, these findings imply an important limitation to the predictability of C cycling and climate under unprecedented environmental conditions. We suggest that the carbon modeling community prioritize a probabilistic multi-model approach to generate more robust C cycle projections.

Cytogenetic characterization of alpaca (Lama pacos, fam. Camelidae) prometaphase chromosomes.

The present study provides specific cytogenetic information on prometaphase chromosomes of the alpaca (Lama pacos, fam. Camelidae, 2n = 74) that forms a basis for future work on karyotype standardization and gene mapping of the species, as well as for comparative studies and future genetic improvement programs within the family Camelidae. Based on the centromeric index (CI) measurements, alpaca chromosomes have been classified into four groups: group A, subtelocentrics, from pair 1 to 10; group B, telocentrics, from pair 11 to 20; group C, submetacentrics, from pair 21 to 29; group D, metacentrics, from pair 30 to 36 plus sex chromosomes. For each chromosome pair, the following data are provided: relative chromosome length, centromeric index, conventional Giemsa staining, sequential QFQ/C-banding, GTG- and RBG-banding patterns with corresponding ideograms, RBA-banding and sequential RBA/silver staining for NOR localization. The overall number of RBG-bands revealed was 391. Nucleolus organizer-bearing chromosomes were identified as pairs 6, 28, 31, 32, 33 and 34. Comparative ZOO-FISH analysis with camel (Camelus dromedarius) X and Y painting probes was also carried out to validate X-Y chromosome identification of alpaca and to confirm close homologies between the sex chromosomes of these two species.

Clinical and functional investigation of 10 missense mutations and a novel frameshift insertion mutation of the gene for copper-zinc superoxide dismutase in UK families with amyotrophic lateral sclerosis.

Mutations of the gene SOD-1, which encodes the enzyme copper-zinc superoxide dismutase, occur in patients with a familial form of amyotrophic lateral sclerosis (ALS). We investigated 71 families with more than one individual affected by ALS for clinical features and SOD-1 mutations. Mutations were identified in 14 families, indicating the presence of SOD-1 mutations in around 20% of this population. There were 10 different heterozygote missense point mutations in eight different codons, and a novel two-base frameshift insertion (132insTT), which leads to substitution of aspartic acid for glutamic acid at codon 132, and a premature stop codon at 133, with predicted truncation of the protein. SOD enzyme activity was reduced to around 50% of normal in individuals with SOD-1 mutations, and may be a useful predictor for the presence of these mutations. A predilection for disease onset in the lower limbs appears to be a distinguishing feature of familial ALS with SOD-1 mutations, and accords with findings in transgenic mouse models. In general, the finding of an SOD-1 mutation does not accurately predict a prognosis or disease severity.

Investigation of a null mutation of the CNTF gene in familial amyotrophic lateral sclerosis.

Neurotrophic factors, such as ciliary neurotrophic factor (CNTF), have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a human neurodegenerative disease primarily of upper and lower motor neurones. A null mutation of the CNTF gene has recently been described. The mutation is an intronic point mutation (G to A) which generates a new splice acceptor site and a 4 bp insertion within the CNTF coding region, and prevents the expression of the normal protein. We investigated this as a candidate gene in 49 families with ALS, where the genetic component may be expected to be strongest. 65% were normal homozygotes, and 35% were heterozygotes for the mutation. No mutant homozygotes were detected. The absence of CNTF protein expression associated with the homozygote mutation does not appear to be of major significance in the development of ALS.

Fornix vs limbal-based trabeculectomy with mitomycin C.

PURPOSE: To compare the effectiveness of limbus- and fornix-based conjunctival flaps in patients undergoing trabeculectomy with mitomycin-C augmentation. METHODS: A retrospective review of the records of 71 consecutive eyes of 59 patients who underwent trabeculectomy with mitomycin C. All the patients had at least 6 months of follow-up. The first 35 eyes underwent surgery with a limbal-based flap, whereas all subsequent surgeries were by fornix-based procedures. RESULTS: No significant difference was detected between the groups with regard to patient demographics, preoperative visual field and intraocular pressure parameters, postoperative intraocular pressures at day 1, months 1, 3, and 6 postoperatively, need for intervention, need for supplementary glaucoma medication, and final visual acuity. There were four cases of overdrainage and hypotony in the limbal-based group, whereas none occurred in the fornix-based group. In all 83% percent of eyes in the limbal-based group achieved intraocular pressures off medication of less than 18 mmHg, whereas 94% of the fornix based group obtained such IOP control. One patient in the limbal-based group developed late postoperative endophthalmitis. CONCLUSION: Trabeculectomy with MMC augmentation is a safe and effective procedure for reduction of IOP and visual rehabilitation whether a fornix- or a limbal-based conjunctival flap is utilised. In this series, there was a greater risk of excessive drainage with subsequent hypotonous complications when surgery was undertaken by a limbal-based procedure.

The mechanical properties of milled and cast titanium for ceramic veneering.

This study compared the mechanical properties of machine-milled pure titanium and cast titanium. The metals were cast or milled to the dimensions of a standard tensile bar pattern. Each group was treated under three different conditions: as-cast (or as-milled), standard heat, and extended heat. Tensile testing found no difference in the mechanical properties of as-cast and as-milled titanium. Heat treatment significantly increased the ultimate tensile strength and the yield strength of cast titanium but had no such effects on milled titanium. There was no significant difference between the two metals in the modulus of elasticity or the percentage of elongation under the three treatment conditions.

Approaches to scaling up physiologically based soil-plant models in space and time.

Many broad-scale, environmental phenomena can be investigated by extrapolating from detailed study of events at a small scale. This paper evaluates approaches to the use of physiologically based soil-plant models for addressing broad-scale, environmental issues. When the space and time domains of a soil-plant simulator are extended, there is an increase in the variability of soil, plant, and weather variables, which can be dealt with by what is called extended-range modeling, ERM. There may also be a gain of phenomena not represented at the small scale, which can be dealt with by what is called phenomena-added modeling, PAM. As an example of ERM, a Monte Carlo procedure, called Latin hypercube sampling, is used to estimate annual photosynthate production of an oak-hickory forest under three atmospheric CO(2) concentrations. Phenomena-added modeling is illustrated by scaling up spatially from a vegetated plot to a watershed, and scaling up temporally from a physiological model with hourly time steps to a forest-succession model operating on annual time steps. Where large-scale processes take place on a time scale similar to, or faster than, that of small-scale processes (plot-watershed case), less computation is required if the small-scale processes are built into the large-scale model and ERM is conducted with the expanded model. Phenomena-added modeling may be conducted by information transfer from a small-scale simulator to a large-scale simulator. This is also possible with Latin hypercube sampling by using the output frequency distributions from the small-scale model as input distributions for the large-scale model. The final outputs at the large scale are also frequency distributions, and these can be used to determine confidence intervals for statistical comparisons among modeling scenarios. The ERM and PAM methods are data and computer intensive; nevertheless, they can fill an important need for addressing large-scale issues that cannot be adequately addressed through other scaling up methods.

Sperm pre-incubation prior to insemination affects the sex ratio of bovine embryos produced in vitro.

The objective of the present study was to determine whether sperm incubation prior to oocyte insemination in vitro affects the sex ratio of resulting blastocyst. Cumulus-oocyte-complexes (COCs) collected from slaughterhouse ovaries were matured in vitro and inseminated with frozen-thawed semen of three proven artificial insemination (AI) bulls pre-incubated in vitro in Sperm-Talp for 6 and 24 h. On day-9 blastocysts were collected and processed for sex determination. More than 80% of blastocyst were successfully sexed. There were no significant differences in cleavage and blastocyst rates using sperm pre-incubated for 6 h as compared with the 0-h pre-incubation control group. The cleavage and blastocyst rates were significantly lower in the 24-h pre-incubation group. The male to female ratio, when compared with the theoretical 1 : 1, differed significantly in favour of females among hatched (viable) blastocysts derived from sperm pre-incubated for 24 h prior to insemination as well as among all blastocytsts in the 6-h group. Moreover, when the sperm treatment was considered, the sex ratio was affected only among hatched blastocysts in 24-h pre-incubation group. It was concluded that prolonged sperm pre-incubation influences the rate of development and the sex ratio among hatched blastocysts.

A comparison of the hardness of different types of titanium and conventional metal ceramics.

This study compared the surface hardness of machine milled titanium and cast titanium, and the surface hardness profile of a gold-palladium alloy, a nickel chromium alloy, milled and cast titanium. For each group, 15 discoid specimens, 10 mm in diameter and 5 mm thick, were fabricated by either casting or milling. Five specimens of each group underwent one of three treatments: (1) no heat treatment, (2) a standard heat treatment, or (3) an extended heat treatment. Knoop hardness values were determined. Results indicated that the Knoop hardness of cast titanium was less than that of the cast titanium standard treatment group, which was less than the Knoop hardness of the cast titanium extended treatment group. Knoop hardness of milled titanium was less than that of the milled titanium standard treatment and milled titanium extended treatment groups. For the surface hardness profile, cast titanium showed a decreasing surface hardness as the distance from the surface of the specimen increased. No such trend was identified for the other groups tested.

Effects of diet and the cholecystokinin antagonist; devazepide (L364,718) on CCK mRNA, and tissue and plasma CCK concentrations.

The mechanisms by which raw soya diets and CCK-receptor antagonists increase postprandial plasma CCK concentrations are not fully understood. Therefore we examined the effects of different diets including raw soya, and the effect of the potent CCK antagonist devazepide in the fed and fasted state on CCK concentrations in plasma and in the duodenal mucosa and on the duodenal CCK:beta-tubulin mRNA ratio in rats. Diets which stimulated high plasma CCK levels, such as raw soya, also gave the highest CCK tissue and mRNA concentrations with a close correlation between plasma and tissue CCK concentrations within each group (r = 0.94, P = 0.018) and between tissue CCK concentrations and CCK:beta-tubulin mRNA ratios (r = 0.91, P = 0.030). Animals fed ad libitum and treated with devazepide (1 mg kg-1) had higher CCK:beta-tubulin mRNA ratios, tissue CCK concentrations and plasma CCK concentrations than animals injected with vehicle. Fasted animals treated with devazepide for 28 h also had higher CCK mRNA:beta-tubulin mRNA ratios (1.86 +/- 0.43 vs. 0.85 +/- 0.15, P < 0.05), and higher tissue CCK concentrations (0.99 +/- 0.09 vs. 0.69 +/- 0.04, P < 0.01). However, despite these intracellular changes devazepide did not elevate plasma CCK concentrations in the fasted state. Therefore, devazepide increases tissue concentrations of CCK but requires an additional dietary stimulus to raise plasma concentrations. These findings indicate that devazepide produces a dissociation between synthesis and release of CCK in fasted animals.

A study of genetic linkage heterogeneity in adult polycystic kidney disease.

The mutation for APKD has previously been localized to chromosome 16 by the demonstration of genetic linkage with both the alpha-chain of hemoglobin and phosphoglycolate phosphatase. These studies were carried out, however, on a limited number of families, and the possibility remained that mutations at other genetic loci might produce the disease. Such genetic heterogeneity of linkage would invalidate the general use of chromosome 16 markers for the purpose of detection of the disease and complicate the characterization of the APKD mutation at the molecular level. Therefore, further families were studied to resolve this issue. A total of 27 Northern European pedigrees were analyzed, all apparently unrelated and with origins in England, Scotland, Holland, and Eastern Finland. No evidence was found to suggest heterogeneity of genetic linkage between alpha-globin and the disease locus in this population.

A study of genetic linkage heterogeneity in adult polycystic kidney disease.

The mutation for adult polycystic kidney disease (APKD) has previously been localised to chromosome 16 by the demonstration of genetic linkage with the loci for the alpha-chain of haemoglobin and phosphoglycolate phosphatase. These studies were carried out, however, on only nine families so that the possibility remained that mutations at other genetic loci might produce the disease. Such genetic heterogeneity of linkage would invalidate the general use of chromosome 16 markers for the purposes of detection of the disease, and complicate the characterisation of APKD at the molecular level. Therefore further families were studied to address this question. A total of 28 northern European pedigrees were analysed, all apparently unrelated, and with origins in England, Scotland, Holland and eastern Finland. No evidence was found to suggest heterogeneity of genetic linkage between alpha-globin and the APKD locus in this population.

Familial amyotrophic lateral sclerosis with a point mutation of SOD-1: intrafamilial heterogeneity of disease duration associated with neurofibrillary tangles.

Mutations of SOD-1 have recently been associated with autosomal dominant familial amyotrophic lateral sclerosis (ALS). A patient is described with a 20 year duration of motor neuron disease, with clinical features of ALS, who was heterozygous for a point mutation ATT to ACT leading to substitution of isoleucine for threonine at codon 113 in exon 4 of SOD-1. This mutation has previously been described in two families with ALS and three apparently sporadic cases of ALS. The patient described here had a family history suggestive of autosomal dominant inheritance of this genetic mutation; other members of the family having a more typical disease duration. Unusual pathological features included neurofibrillary tangles in neurons of the globus pallidus, substantia nigra, locus coeruleus, and inferior olivary nuclei, and absence of ubiquitin immunoreactive inclusions in motor neurons. This may reflect the slow progression of the neurodegeneration associated with the SOD-1 mutation in this patient. The prolonged survival, of over 20 years, with other family members having a more typical survival of two to three years, has important implications for genetic counselling in families with ALS in addition to the fundamental biological questions concerning the influence of these mutations on disease expression.