Biodiversity and ecology of flower-associated actinomycetes in different flowering stages of Protea repens.

Actinomycete bacteria have previously been reported from reproductive structures (infructescences) of Protea (sugarbush/suikerbos) species, a niche dominated by fungi in the genera Knoxdaviesia and Sporothrix. It is probable that these taxa have symbiotic interactions, but a lack of knowledge regarding their diversity and general ecology precludes their study. We determined the diversity of actinomycetes within Protea repens inflorescence buds, open inflorescences, young and mature infructescences, and leaf litter surrounding these trees. Since the P. repens habitat is fire-prone, we also considered the potential of these bacteria to recolonise infructescences after fire. Actinomycetes were largely absent from flower buds and inflorescences but were consistently present in young and mature infructescences. Two Streptomyces spp. were the most consistent taxa recovered, one of which was also routinely isolated from leaf litter. Lower colonisation rates were evident in samples from a recently burnt site. One of the most consistent taxa isolated from older trees in the unburnt site was absent from this site. Our findings show that P. repens has a distinct community of actinomycetes dominated by a few species. These communities change over time and infructescence developmental stage, season and the age of the host population. Mature infructescences appear to be important sources of inoculum for some of the actinomycetes, seemingly disrupted by fire. Increased fire frequency limiting maturation of P. repens infructescences could thus impact future actinomycete colonisation in the landscape. Streptomyces spp. are likely to share this niche with the ophiostomatoid fungi, which merits further study regarding their interactions and mode of transfer.

Fire impacts bacterial composition in Protea repens (Proteaceae) infructescences.

The diverse bacterial communities in and around plants provide important benefits, such as protection against pathogens and cycling of essential minerals through decomposition of moribund plant biomass. Biodiverse fynbos landscapes generally have limited deadwood habitats due to the absence of large trees and frequent fire. In this study, we determined the effect of a fire disturbance on the bacterial communities in a fynbos landscape dominated by the shrub Protea repens using 16S ribosomal RNA amplicon sequencing. The bacterial community composition in newly formed fruiting structures (infructescences) and soil at a recently burnt site was different from that in an unburnt site. Bacteria inhabiting P. repens infructescences were similar to well-known taxa from decomposing wood and litter. This suggests a putative role for these aboveground plant structures as reservoirs for postfire decomposer bacteria. The results imply that inordinately frequent fires, which are commonplace in the Anthropocene, are a significant disturbance to bacterial communities and could affect the diversity of potentially important microbes from these landscapes.

[Intracranial pressure and hypotonic infusion solutions]. / Intrakranieller Druck und hypotone Infusionslösungen.

The physiological osmolality of plasma is 288+/-5 mosmol/kgH2O when measured by freezing-point depression. The theoretical osmolarity (290 mosmol/l) calculated from composition, osmotic coefficient (0.93) and water content (0.94) is practically identical. Saline (0.9% NaCl) has an osmolarity of 308 mosmol/l and an osmolality of 286 mosmol/kgH2O (water content ca. 1.0). The osmolality in vivo is more important than that measured in vitro. A 5% dextrose solution in water (D5W) is isotonic in vitro, but the in vivo effect is that of pure water because the glucose is rapidly metabolized. Every infusion fluid should be isotonic (290+/-10 mosmol/kgH2O). Hypotonic solutions must move water from the extracellular space to the intracellular space. Typical examples are Ringer's lactate and acetate solutions (256 instead of 290 mosmol/kgH2O). The brain (central nervous system, CNS) is the critical organ: The rigidly shaped skull contains three incompressible compartments, only blood and cerebrospinal fluid (CSF) can be partially, but limitedly shifted outside the skull. The consequence of a volume load is an increasing intracranial pressure (ICP). A decrease in plasma osmolality by only 3% produces an increase in ICP of about 15 mmHg. Therefore, infusion of larger volumes of hypotonic solutions should be avoided at all costs.

Observations of long-lived anthropogenic halocarbons at the high-Alpine site of Jungfraujoch (Switzerland) for assessment of trends and European sources.

Anthropogenic halocarbons, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), bromocarbons (halons) and long-lived chlorinated solvents have been measured continuously at the high-Alpine site of Jungfraujoch (Switzerland) since January 2000. Chloro- and bromo-containing halocarbons are responsible for the stratospheric ozone depletion and will be globally banned from usage within the next years. With the exception of the stable CFC-12 (CF2 Cl2), all major CFCs and chlorinated solvents show a negative trend in recent years in their background concentrations at Jungfraujoch. HCFCs, as their first-generation substitute, are still increasing with a few percent per year. However, the frequency and the strength of HCFCs pollution events, which are caused by regional European emissions, are already declining. This can be seen as a sign of the impending ban of these gases within the next years in Europe. On the other hand, HFCs as the second-generation substitutes, are increasing with relative rates of at least 10% per year (e.g. almost 5 ppt per year for HFC-134a). An allocation of European sources was attempted by combining measured concentrations with trajectories of air masses reaching the Jungfraujoch during pollution events. Potential source regions could be detected in Italy, France, Spain and Germany.

Our changing atmosphere: evidence based on long-term infrared solar observations at the Jungfraujoch since 1950.

The Institute of Astrophysics of the University of Liège has been present at the High Altitude Research Station Jungfraujoch, Switzerland, since the late 1940s, to perform spectrometric solar observations under dry and weakly polluted high-mountain conditions. Several solar atlases of photometric quality, extending altogether from the near-ultra-violet to the middle-infrared, were produced between 1956 and 1994, first with grating spectrometers then with Fourier transform instruments. During the early 1970s, scientific concerns emerged about atmospheric composition changes likely to set in as a consequence of the growing usage of nitrogen-containing agricultural fertilisers and the industrial production of chlorine-bearing compounds such as the chlorofluorocarbons and hydro-chlorofluorocarbons. Resulting releases to the atmosphere with ensuing photolysis in the stratosphere and catalytic depletion of the protective ozone layer prompted a worldwide consortium of chemical manufacturing companies to solicit the Liège group to help in clarifying these concerns by undertaking specific observations with its existing Jungfraujoch instrumentation. The following pages evoke the main steps that led from quasi full sun-oriented studies to priority investigations of the Earth's atmosphere, in support of both the Montreal and the Kyoto Protocols.

Screening California surface waters for estrogenic endocrine disrupting chemicals (EEDC) with a juvenile rainbow trout liver vitellogenin mRNA procedure.

Concern regarding the occurrence of chemicals that disrupt endocrine system functions in aquatic species has heightened over the last 15 years. However, little attention has been given to monitoring for estrogenic endocrine disrupting chemicals (EEDCs) in California's freshwater ecosystems. The objective was to screen surface water samples for estrogenic activity using vitellogenin (Vtg) mRNA quantification in livers of juvenile rainbow trout by real-time reverse transcriptase polymerase chain reaction (Q-RT PCR). Vtg mRNA analysis of livers from fish exposed to 113 ambient water samples collected from surface waters in California's Central Valley and northern area indicated that six samples (5% of total) may have contained EEDCs. The six samples induced marginal, but statistically significant, increases of Vtg mRNA. No ambient water sample evoked Vtg mRNA responses equivalent to those in positive controls (all responses were less than 2% of the positive control response). Thus, EEDC concentrations in these samples were low (at or near the threshold for the procedure) or results may have included false positives. To establish a more definitive assessment of EEDC occurrence, follow-up screening at sites where statistically significant, but weak, estrogenic activity was observed is recommended. Overall, results reveal that a majority of the California surface waters tested were below EEDC detection threshold concentration for the screening procedure utilized.

Antifungal Streptomyces spp. Associated with the Infructescences of Protea spp. in South Africa.

Common saprophytic fungi are seldom present in Protea infructescences, which is strange given the abundance of mainly dead plant tissue in this moist protected environment. We hypothesized that the absence of common saprophytic fungi in Protea infructescences could be due to a special symbiosis where the presence of microbes producing antifungal compounds protect the infructescence. Using a culture based survey, employing selective media and in vitro antifungal assays, we isolated antibiotic producing actinomycetes from infructescences of Protea repens and P. neriifolia from two geographically separated areas. Isolates were grouped into three different morphological groups and appeared to be common in the Protea spp. examined in this study. The three groups were supported in 16S rRNA and multi-locus gene trees and were identified as potentially novel Streptomyces spp. All of the groups had antifungal activity in vitro. Streptomyces sp. Group 1 had inhibitory activity against all tested fungi and the active compound produced by this species was identified as fungichromin. Streptomyces spp. Groups 2 and 3 had lower inhibition against all tested fungi, while Group 3 showed limited inhibition against Candida albicans and Sporothrix isolates. The active compound for Group 2 was also identified as fungichromin even though its production level was much lower than Group 1. The antifungal activity of Group 3 was linked to actiphenol. The observed antifungal activity of the isolated actinomycetes could contribute to protection of the plant material against common saprophytic fungi, as fungichromin was also detected in extracts of the infructescence. The results of this study suggest that the antifungal Streptomyces spp. could play an important role in defining the microbial population associated with Protea infructescences.

Tumor tissue oxygenation as evaluated by computerized-pO2-histography.

A computerized pO2 measurement system with a novel electrode motion pattern (Sigma-pO2-histography) was evaluated in vitro and in vivo. The system was found to be reliable in 0.9% saline and 10% hydroxyethylene starch solution and in fresh donor blood. Marked deviations were found in lipid and hemoglobin solutions and in fluorocarbon emulsions. Histograms obtained in rat liver, mouse muscle, and subcutis were similar to previously reported distributions. Direct comparison between Sigma-Eppendorf and self-constructed Whalen-type electrodes in hypoxic tumors gave similar results. A large series of measurements indicated that hypoxic and anoxic tissue areas were frequently found both in isografted rodent and in xenografted human tumors. The extent of oxygen deprivation depended on the cell line studied, tumor size, implantation site, the vascularity, and the actual tissue perfusion. Pentobarbital anesthesia redistributed the tumor oxygenation without affecting the median pO2 value. Tumors growing in a pre-irradiated bed were less oxygenated than those at untreated sites. Hyperthermia at therapeutically relevant temperatures reduced pO2 levels in adequately oxygenated tumors whereas little change was detected in poorly oxygenated tumors. First measurements in tumors in patients revealed marked inter- and intratumor heterogeneity. It is concluded that this novel technique is suitable for routine measurements of tissue oxygenation of solid tumors in situ.

Alteration of anion gap during almost total plasma replacement with synthetic colloids in piglets.

In ten piglets (body weight 8.2-11.6 kg), acid base, electrolyte and anion gap changes were investigated during almost total plasma replacement with hydroxyethyl starch (HES) and modified fluid gelatin (GEL) in saline solution using a cell saver autotransfusion technique. During the study, there were only moderate acid base changes, but marked disturbances in anion balance. At study end, the mean chloride concentration was significantly higher (mmol/l: normal values 97-108, HES 116 +/- 1.5, GEL 108 +/- 1.1, p < 0.01) and the mean anion gap was significantly lower in the HES group in comparison to the GEL group (mmol/l: normal values 5-14, HES 3 +/- 1.7, GEL 11.9 +/- 0.9, p < 0.01). It is concluded that plasma replacement with electroneutral HES, but not with negatively charged GEL, can lower the anion gap irrespective of the underlying disease. This can be misleading when the anion gap is used for differential diagnosis of metabolic acidosis in patients after large volume infusion of synthetic colloids.

A new photometric method for oxygen consumption measurements in cell suspensions.

A new technique is described for measuring O2 consumption rates and O2 concentrations in suspensions of respiring cells. Aliquots of a cell suspension kept in a special thermostated precision syringe are injected into the measuring system in defined time intervals. The O2 content of these samples is determined photometrically, as reported previously. The O2 consumption per cellular wet weight and/or per single cell can be calculated from the cell volume fraction, the physical density, the cell concentration in the suspension, and the time-dependent decline of the O2 concentration in the precision syringe. The minimum detectable amount of O2 is 0.1 microliter O2, which corresponds to 0.001 (vol/vol) of O2 if a 100-microliters sample of suspended cells is analyzed. Reproducibility of the O2 consumption measurement is 9% of the measured value. The advantages offered by this method are the straightforward calibration in absolute terms, the short time required for one analysis (2-6 min), a high sensitivity, the simultaneous determination of overall O2 concentration and O2 consumption rates in cell suspensions, and the great variability in the application.

Alkaline haematin D-575, a new tool for the determination of haemoglobin as an alternative to the cyanhaemiglobin method. I. Description of the method.

A new method for the rapid and accurate measurement of haemoglobin has been developed as an alternative to the conventional cyanhaemiglobin method. This method is based on the conversion of all haeme, haemoglobin, and haemiglobin species into a stable end product by an alkaline solution of a non-ionic detergent ('AHD reagent'). The reaction product, designated as alkaline haematin D-575, is extremely stable and shows a characteristic absorption peak at 575 nm. As compared to the cyanhaemiglobin method, the determination of haemoglobin by alkaline haematin D-575 offers several advantages such as (1) extreme stability of the AHD reagent and the conversion product, (2) decreased conversion time of all haemoglobin species into the end product, (3) decreased amounts of plasma and cell errors, and errors caused by delayed conversion of carboxy- and fetal haemoglobins, and (4) standardisation by a primary standard (purified crystalline chlorohaemin).

Alkaline haematin D-575, a new tool for the determination of haemoglobin as an alternative to the cyanhaemiglobin method. II. Standardisation of the method using pure chlorohaemin.

Chlorohaemin with high purity (greater than 99%), a stable and well-defined compound, can be used as a primary standard for the standardisation of a haemoglobin assay based on alkaline haematin D-575 [6]. Dissolved in a solution of 25 g Triton X-100 per litre of 0.1 mol/l NaOH ('AHD solution'), the millimolar absorbance coefficient of the end product (alkaline haematin D-575) is 6.960 +/- 0.046 [l X mmol-1 X cm-1] at 575 nm. Within the range of haemoglobin concentrations of 5 to 25 g/100 ml there is a strong linear relation between chlorohaemin concentration and absorbance with a deviation of less than or equal to 2% from the theoretical values. As compared to the conventional cyanhaemiglobin standard solutions, standardisation with pure chlorohaemin is the method of choice because of the simplicity of the preparation of standard solutions, which can be done in every laboratory, and the stability of both the solid compound chlorohaemin and its solutions in alkaline Triton X-100. For the first time a real standard for quality control in haemoglobinometry is recommended: a concentrated solution which behaves like blood, i.e. the simulation of all steps in haemoglobin determination (dilution and photometry) is possible.

Solubility of NH3 and apparent pK of NH4+ in human plasma, isotonic salt solutions and water at 37 degrees C.

The solubility of ammonia, alphaNH3 (mM/mmHg), was determined at 37 degrees C and low ammonia partial pressure (0.02-1 mmHg) in pure water (n =24) as 46.70+/-0.40; aqueous isotonic salt solutions (n = 7) as 46.8+/-0.81; and human plasma (n = 5) as 42.0+/-0.66. The last figure increases to 45.3+/-0.63 if expressed in molal units (mmol/kg plasma water x mmHg) instead of molarity with respect to the water content of the plasma (mean from four healthy and fasting donors: 0.908+0.005 kg H2O/kg plasma; mean density at 37 degrees C: 1.020+/-0.002 kg/l). In pure water, the solubility value is the mean of three different methods: (a) extrapolation of the salting-out effect of ammonia in aqueous NaOH to zero concentration; (b) slope of Henry-Dalton's law and (c) directly measured in pure water and 0.001 M aqueous NaOH. Based on the Henderson-Hasselbalch equation for the system NH4/NH3 in isotonic salt solutions and human plasma, both constants, apparent pK and solubility, can be derived from total ammonia concentration and pH at equilibrium with defined ammonia gas phase, if additionally the concentration of NH4 or NH3 is known. This was verified, in the first case, by determining the concentration of NH4+ by the experimental conditions, and in the second, by two measurements of total ammonia concentration at two different pH values. Total ammonia concentration was measured by a specific enzymatic standard test and pH with the glass electrode. The mean apparent pK was 8.968+/-0.013 in isotonic salt solutions (n = 7), and in human plasma (n = 10) it was 9.014+/-0.033.

Early defibrillation by emergency physicians or emergency medical technicians? A controlled, prospective multi-centre study.

UNLABELLED: In a controlled, prospective multi-centre study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany--defibrillation by emergency physicians (EPs)-in order to answer the following questions: can EMTs in a two-tiered emergency medical services (EMS) system with physicians in the field defibrillate earlier than, and as safely as EPs? Does defibrillation by EMTs (study group) affect survival rate and long-term prognosis of patients in ventricular fibrillation (VF), as compared with the current national standards in resuscitation (basic cardiopulmonary resuscitation (CPR) by EMTs, and defibrillation by physicians: control group? METHODS: Prior to the onset of the study, all EMTs completed retraining in basic life support (BLS). Randomly assessed EMTs were then trained to use semi-automatic defibrillators. With the help of on-line tape recordings, the complete resuscitation sequence was evaluated. Follow-up of the patients was carried out with the help of the Glasgow Coma Scale as well as Pittsburgh Cerebral and Overall Performance Categories. RESULTS: A total of 159 patients with VF were included in the study. In 121 cases, collapse was witnessed. Of the patients receiving defibrillation by EMTs 25% were discharged from hospital alive, compared to 24% of the patients defibrillated by EPs. Of the study patients 67% were defibrillated within 12 min, while the percentage of control patients was 46%. Study patients were defibrillated earlier (P < 0.01), the return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05), and the rate of patients requiring no adrenalin during resuscitation was higher in the study group (P < 0.05). The total amount of adrenalin administered in the study group was lower (P < 0.05). No statistically significant differences were found concerning the neurologic long-term prognosis. CONCLUSIONS: In our study, EMT defibrillation was equally effective as defibrillation by EPs, but failed to improve survival rates or long-term outcome of patients in VF significantly, compared to EP defibrillation. Due to a reduction in the time intervals from collapse to defibrillation and to ROSC, as well as in adrenalin doses, by EMT-defibrillation, EMTs in Germany should defibrillate if they reach a patient prior to an EP, provided they have received continuous medical training and supervision.

Mathematical model for the calculation of oxygen concentrations in a closed circuit oxygen rebreathing apparatus.

BACKGROUND: Closed circuit oxygen rebreathing diving apparatus are used by armed forces in special tasks because of their advantages of long endurance, low noise and minimal gas escape. There is little knowledge about the administered oxygen concentrations in these systems. Closed circuit oxygen rebreathing apparatus are also used as a first aid device for the treatment of severe disorders. Because of similar constructive components, these rebreathing apparatus are comparable to the Dräger LAR V model. HYPOTHESIS: This study was conducted to measure the oxygen concentrations in the LAR V and estimate the correlation between oxygen concentration and pre-breathing purges. METHOD: Subjects were 12 males who performed the pre-breathing procedure. The oxygen concentrations in the breathing loop were measured after each purge. RESULTS: The oxygen concentrations depended on the volume of the apparatus dead space, the total capacity of the divers breathing system respective to the volume of the breathing purges and the number of pre-breathing purges. The maximum oxygen concentration was reached after eight purges (O2 = 85%). An equation to estimate the oxygen concentration inside the LAR V and first aid rebreather was derived. CONCLUSIONS: The results indicated that the present purging procedure (three purges) before diving is normally not sufficient to remove the nitrogen totally from the deadspace of the LAR V, the divers airways and lungs. Only a small modification (six purges) is necessary to improve the safety of the diver in case of a diving apparatus malfunction during the mission profile.

The oxygen status of arterial human blood.

The oxygen status of arterial human blood is described at least by four variables: Oxygen partial pressure (pO2, mmHg), oxygen saturation (sO2, %), hemoglobin content (cHb, g/dL) and oxygen content (cO2, mL/dL). Beside perfusion, however, the oxygen supply of all organs is decisively determined by the mean capillary pO2 which itself is primarily dependent on the arterial cO2. Therefore, the oxygen availability (cardiac output x caO2, mL/min) may be described by the cO2 value in arterial blood or those variables who determine the latter one. The diagnostic significance of the O2 variables of the oxygen status consequently increases in the order of pO2, sO2 (cHb) and cO2. In arterial blood, oxygen partial pressure is the result of O2 diffusion within the lungs into the blood (lung function). Oxygen saturation describes the portion of chemically bound oxygen expressed as O2Hb in relation to total Hb (Hb + O2Hb + COHb + MetHb). Oxygen content is the total amount of oxygen in blood chemically bound plus physically dissolved. Under pathophysiological conditions the diagnostic significance becomes very clear. Disturbances of lung function decreases all three variables, pO2 (hypoxia), sO2 (hypoxygenation) and cO2 (hypoxemia), to produce hypoxic hypoxemia. Carbon monoxide poisoning or methemoglobin formation decreases two variables, sO2 and cO2, where the pO2 remains normal and results in toxic hypoxemia. Anemia with a decrease in the hemoglobin content lowers cO2 only, while pO2 and sO2 remain normal (anemic hypoxemia).

Oxygen parameters of blood: definitions and symbols.

Definitions and symbols for relevant parameters of the oxygen status of arterial blood are recommended. The recommendations are as simple as possible, easy to understand, and devoid of misinterpretations and double meanings. The authors propose no new definitions for limited new methods, no combination of symbols and methods, and no association between definition, symbol and commercial name.