Die Bedeutung des Erhaltungsstoffwechsels und der „maximalen”︁ Ausbeute

This paper examines the microbial denitrification of a medium containing acetate as C-source and of an industrial effluent containing volatile fatty acids as main components a ndphenolics as minor components. Values for m and Y_max are represented. It has been concluded that the maintenance coefficient comprises also those processes not involved in the maintenance metabolism of the cells. The least fraction of the rate of substrate utilization of this extended maintenance metabolism has been expressed by m · 100/q_max. From the values of Y_max a P/2e-ratio < 1 and the equation of cell synthesis have been evaluated.     

“Hypothetical Mean Organisms” of Mycobacteria

Seven hundred fifty-four strains of mycobacteria were examined using 97 characters, and a “Hypothetical Mean Organism” (HMO) was prepared for each species using numerical classification. The species could be defined as a group of strains showing a mean S-value of 90% or more to a HMO and showing mean S-values of 89% or less to other HMOs. The following species were recognized: (1) M. tuberculosis, combining M. tuberculosis and M. bovis into one species; (2) M. kansasii; (3) M. novum; (4) M. avium, combining M. avium, M. nonchromogenicum, M. gastri, M. intracellulare and M. scrofulaceum into one species; (5) M. marinum; (6) M. thermoresistibile; (7) M. chitae; (8) M. borstelense; (9) M. abscessus; (10) M. fortuitum; (11) M. phlei; (12) M. aurum; (13) M. parafortuitum; (14) M. lacticola; (15) M. smegmatis. Dendrogram of the species showed two main stems, indicating that the genus Mycobacterium be divided into two subgenera, subgenus Mycobacterium (from M. tuberculosis to M. chitae) and subgenus My cornycobacterium (from M. borstelense to M. smegmatis). Some discrepancy was noted between the results of numerical classification using HMOs and that of the “proper” numerical classification, and this discrepancy is discussed.     

Curious structure in “canonical” alanine-based peptides

We have performed all atom simulations of blocked peptides of the form (AAXAA)₃, where X = Gln, Asn, Glu, Asp, Arg, and Lys with explicit water molecules to examine the interactions between side chains spaced i,i–5 in the sequence. Although side chains in this i,i–5 arrangement are commonly believed to be noninteracting, we have observed the formation of unusual i,i–5 main chain hydrogen bonding in such sequences with positively charged residues (Lys) as well as polar uncharged groups (Gln). Our results are consistent with the unusual percentage of hydrogen bonding curves produced by amide exchange measurements on the well-studied sequence acetyl-(AAQAA)₃-amide in water (Shalongo, W., Dugad, L., Stellwagen, E. J. Am. Chem. Soc. 116:8288–8293, 1994). Analysis of our simulations indicated that the glutamine side chain showed the greatest propensity to support π helix formation and that the i,i–5 intramolecular hydrogen bonds were stabilized by water-bridging side chain interactions. This intermittent formation of the unusual π helix structure was observed for up to 23% of the total simulation time in some residues in (AAQAA)₃. Control studies on peptides with glutamine side chains spaced i,i–3, i,i–4, and i,i–6 did not reveal similar unique structures, providing stronger evidence for the unique role side chain interactions with i,i–5 spacing. © 1997 Wiley-Liss Inc.     

Spatial structure in the “Plastisphere”: Molecular resources for imaging microscopic communities on plastic marine debris

Plastic marine debris (PMD) affects spatial scales of life from microbes to whales. However, understanding interactions between plastic and microbes in the “Plastisphere”—the thin layer of life on the surface of PMD—has been technology‐limited. Research into microbe–microbe and microbe–substrate interactions requires knowledge of community phylogenetic composition but also tools to visualize spatial distributions of intact microbial biofilm communities. We developed a CLASI‐FISH (combinatorial labelling and spectral imaging – fluorescence in situ hybridization) method using confocal microscopy to study Plastisphere communities. We created a probe set consisting of three existing phylogenetic probes (targeting all Bacteria, Alpha‐, and Gammaproteobacteria) and four newly designed probes (targeting Bacteroidetes, Vibrionaceae, Rhodobacteraceae and Alteromonadaceae) labelled with a total of seven fluorophores and validated this probe set using pure cultures. Our nested probe set strategy increases confidence in taxonomic identification because targets are confirmed with two or more probes, reducing false positives. We simultaneously identified and visualized these taxa and their spatial distribution within the microbial biofilms on polyethylene samples in colonization time series experiments in coastal environments from three different biogeographical regions. Comparing the relative abundance of 16S rRNA gene amplicon sequencing data with cell‐count abundance data retrieved from the microscope images of the same samples showed a good agreement in bacterial composition. Microbial communities were heterogeneous, with direct spatial relationships between bacteria, cyanobacteria and eukaryotes such as diatoms but also micro‐metazoa. Our research provides a valuable resource to investigate biofilm development, succession and associations between specific microscopic taxa at micrometre scales.     

Dopamine for “Wanting” and Opioids for “Liking”: A Comparison of Obese Adults With and Without Binge Eating

Obesity research suffers from an overinclusion paradigm whereby all participants with a BMI beyond a certain cutoff value (e.g., 30) are typically combined in a single group and compared to those of normal weight. There has been little attempt to identify meaningful subgroups defined by their salient biobehavioral differences. In order to address this limitation, we examined genetic and psychological indicators of hedonic eating in obese adults with (n = 66) and without (n = 70) binge eating disorder (BED). Our analyses focused on dopamine (DA) and opioid genetic markers because of their conjoint association with the functioning of brain reward mechanisms. We targeted three functional polymorphisms related to the D2 receptor (DRD2) gene, as well as the functional A118G polymorphism of the mu‐opioid receptor (OPRM1) gene. We found that significantly more obese controls had the “loss‐of‐function” A1 allele of Taq1A compared to their BED counterparts, whereas the “gain‐of‐function” G allele of A118G occurred with greater frequency in the BED group. A significant gene–gene combination χ² analysis also indicated that of those participants with the gain‐gain genotype (G⁺ and A1), 80% were in the BED group whereas only 35% with the loss‐loss genotype (G^? and A1⁺) were in this group. Finally, BED subjects had significantly higher scores on a self‐report measure of hedonic eating. Our findings suggest that BED is a biologically based subtype of obesity and that the proneness to binge eating may be influenced by a hyper‐reactivity to the hedonic properties of food—a predisposition that is easily exploited in our current environment with its highly visible and easily accessible surfeit of sweet and fatty foods.     

Comparisons of the Colonisation by Invertebrates of Three Species of Wood,Alder Leaves,and Plastic “Leaves” in a Temperate Stream

Small woody debris in streams is abundant, and may be a food source or may provide a substrate on which other food sources such as biofilm may develop, both of which may be significant to invertebrates in times of food scarcity. We examined patterns of invertebrate colonisation of small woody debris (veneers of red alder, Douglas‐fir, and western red cedar), red alder leaves, and plastic (as an inert substrate to mimic leaves). Invertebrate colonisation was high on alder leaves, but low on wood substrates and plastic, controlling for the available surface area. Detritivorous invertebrates had significantly higher colonisation rates of alder leaves versus the other four substrates, whereas predators and collectors did not (consistent with their use of these as substrates and not food). All wood decreased in mass by <15% and leaves by ∼50% over the 75 days of the experiment. For all taxa tested, there was no significant difference in their colonisation of the wood veneers versus the plastic sheets. These results suggest that wood was not directly used by these invertebrates as a food source, or that there could be similar biofilm development on the surfaces of these substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

ORIGIN AND RECENT ENDEMIC DIVERGENCE OF A CASPIAN MYSIS SPECIES FLOCK WITH AFFINITIES TO THE “GLACIAL RELICT” CRUSTACEANS IN BOREAL LAKES

Aspects of the evolution of intralacustrine species flocks and of the origin of the Arctic or “glacial-relict” zoogeographical element in Eurasian inland waters were elucidated in an allozyme study of the crustacean genus Mysis. This element, of supposedly northern marine ancestry, is represented by vicarious taxa in the deeper parts of the Caspian Sea (an enclosed ancient basin) and in young boreal lakes. The three endemic Caspian Mysis species studied are very close genetically (Nei's D = 0.06), which suggests a recent intrabasin radiation and rapid morphological divergence. This is in contrast to the pattern in postglacial Holarctic boreal lakes, where the Mysis relicta group is represented by a set of morphologically uniform but probably much older sibling species (D = 0.3–0.6). The results provide a parallel to those on the recent diversification of some fish species flocks in ancient freshwater lakes. The situation is, however, unusual in that the Caspian sympatric Mysis flock is pelagic, and conditions promoting speciation through allopatric isolation or spatial segregation by trophic substrate specialization seem implausible. The monophyletic Caspian Mysis clade shows a relatively strong divergence from both the northern lacustrine and the Arctic marine congeners (D = 0.6–1.0); the phylogenetic branching order of these three zoogeographical groups is not conclusively resolved. The results contradict the prevailing hypothesis of a recent Pleistocene origin of the Caspian Arctic element by invasion from Eastern European continental proglacial lakes that drained south to the Caspian basin during the glacial maxima and served as refugia for the boreal lacustrine taxa.     

The theoretical analysis of kinetic behaviour of “hysteretic” allosteric enzymes III. Dissociating and associating enzyme systems in which the rate of installation of equilibrium between the oligomeric forms is comparable to that of enzymatic reaction

The curves of the time (t) dependent product (Pr) accumulation for Monod, Wyman & Changeux model (1965), where the rate of installation of equilibrium between two conformational states of oligomeric enzyme (R T) is comparable to that of enzymatic process, are theoretically analysed. It is assumed that the complexes of R and T forms are in rapid equilibrium with the free components. The character of the effective rate constant of conformational transition R T and the value of τ (where τ is the intercept of the linear part of the kinetic curve of [Pr] versus t with the time axis) versus the substrate concentration is analysed. It is also shown that slow conformational transition R T can be manifested by an unusual shape for Monod et al. model plots of initial velocity of the enzyme reaction v. the substrate concentration (these curves can clearly display expressed inflection points and Hill's cooperativity coefficient less than unity).     

Adult Female Rats Defend “Appropriate” Energy Intake after Adaptation to Dietary Energy

Objective: To determine if adult female rats adapt to lower and higher dietary energy density. Research Methods and Procedures: Study 1 compared high‐fat (56%), high‐energy density (HD) (21.6 kJ/g) and high‐fat (56%), low‐energy density (LD) (16.0 kJ/g) diets before surgery (two groups, 2 weeks, n = 16) and after surgery [ovariectomy (O) Sham (S); 2 × 2 factorial, n = 8; 6 weeks]. The second study (no surgery) compared high‐fat (60.0%), high‐energy (22.0 kJ/g) and low‐fat (10.0%), low‐energy (15.1 kJ/g) diets (n = 8). Results: In study 1, food intake was similar for the first 2 weeks, but rats on the LD diet consumed less energy, gained less weight, and had lower nonfasted serum leptin (all p < 0.0001) than rats on the HD diet. After surgery, rats on the LD and HD diets had similar weight gain, but rats on the LD diet consumed more food (p < 0.0001) and less energy (p < 0.009). O rats consumed more food and gained more weight (p < 0.0001) than S rats. Results from study 2 were similar to those from study 1. Discussion: The results demonstrated that O and S surgery rats and rats with no surgery adjust their food intake to defend a level of energy intake. This defense only occurred after a 2‐week adaptation period. The major differences in final body weights and abdominal fat resulted from the initial 2 weeks before adaptation to energy density. Rats fed higher‐energy diets seemed to “settle” at a higher level of adiposity, and rats fed lower‐energy diets consumed more food to increase energy consumption.     

A Taxonomic Study of Strains Received as “Mycobacterium” rhodochrous

A taxonomic study was carried out on 20 strains received as “Mycobacterium” rhodochrous. These strains were exceedingly similar to the strains of the genus Gordona recently proposed by the present author. Out of the 20 strains studied, 10 strains, including two strains previously named Rhodococcus rhodochrous, formed one cluster and were considered to belong to a species of the genus Gordona. The species has been named Gordona rhodochroa (Zopf; Overbeck; Gordon et Mihm) Tsukamura comb. nov. Two strains were considered to belong to the species Gordona rubra. One of the two had initially been named Mycobacterium rubropertinctum. It was considered from the facts that the specific epithet for the species should be “rubropertinta” and the name Gordona rubra be changed to Gordona rubropertincta. The other strains seemed to belong to some other species. In conclusion, the species “Mycobacterium” rhodochrous appears to be divided into several species of the genus Gordona.     

Role of arylalkylamine <Emphasis Type="Italic">N</Emphasis>-acetyltransferase in regulation of biogenic amines levels by gonadotropins in <Emphasis Type="Italic">Drosophila</Emphasis>

The effect of 20-hydroxyecdysone (20E) and the juvenile hormone (JH) on the activity of the arylalkylamine N-acetyltransferase (AANAT) was studied in young females of wild-type D. virilis and D. melanogaster. 20E feeding of the flies led to a decrease in AANAT activity in both species when dopamine (DA) was used as substrate, but did not affect the enzyme activity when octopamine (OA) was used as substrate. JH application increased AANAT activity with DA as substrate in both species, but did not change it with OA as substrate. AANAT activity was also measured in young females of a JH-deficient strain of D. melanogaster, apterous ^56f . A decrease in the enzyme activity was observed in the mutant females as compared to wild-type. Mechanisms of regulation of DA level by gonadotropins in Drosophila are discussed.     

Dietary Restraint and Control Over “Wanting” Following Consumption of “Forbidden” Food

Eating behavior can be influenced by the rewarding value of food, i.e., “liking” and “wanting.” The objective of this study was to assess in normal‐weight dietary restrained (NR) vs. unrestrained (NU) eaters how rewarding value of food is affected by satiety, and by eating a nonhealthy perceived, dessert‐specific food vs. a healthy perceived, neutral food (chocolate mousse vs. cottage cheese). Subjects (24NR age = 25.0 ± 8.2 years, BMI = 22.3 ± 2.1 kg/m²; 26NU age = 24.8 ± 8.0 years, BMI = 22.1 ± 1.7 kg/m²) came to the university twice, fasted (randomized crossover design). Per test‐session “liking” and “wanting” for 72 items divided in six categories (bread, filling, drinks, dessert, sweets, stationery (placebo)) was measured, before and after consumption of chocolate mousse/cottage cheese, matched for energy content (5.6 kJ/g) and individual daily energy requirements (10%). Chocolate mousse was liked more than cottage cheese (P < 0.05). After consumption of chocolate mousse or cottage cheese, appetite and “liking” vs. placebo were decreased in NR and NU (P < 0.03), whereas “wanting” was only decreased in NR vs. NU (P ≤ 0.01). In NR vs. NU “wanting” was specifically decreased after chocolate mousse vs. cottage cheese; this decrease concerned especially “wanting” for bread and filling (P < 0.05). To conclude, despite similar decreases in appetite and “liking” after a meal in NR and NU, NR decrease “wanting” in contrast to NU. NR decrease “wanting” specifically for a nonhealthy perceived, “delicious,” dessert‐specific food vs. a nutritional identical, yet healthy perceived, slightly less “delicious,” “neutral” food. A healthy perceived food may thus impose greater risk for control of energy intake in NR.     

“Ecological Armageddon” – more evidence for the drastic decline in insect numbers

The efficient use of nitrogen by crops can minimise environmental risks and maximise returns to farmers. Under organic farming systems, this can be achieved by adjusting the fertilisation management and/or using genetic variability. Seven durum wheat (Triticum durum) cultivars and three emmer (Triticum dicoccum) cultivars were assessed under an organic farming system over a non‐consecutive 4‐year period (2005–11) in Foggia (southern Italy). The objectives were to investigate the agronomic and qualitative characteristics, and to evaluate the agronomic efficiency and adaptability according to three N fertilisation levels (0, 40, 80 kg N ha^?1). A split‐plot design was used, with three replications in each year. Nine traits were investigated: heading time, plant height, seed yield, number of spikes m^?2, harvest index, specific weight, 1000‐seed weight, and protein and gluten contents. Increasing N to 80 kg ha^?1 increased plant height (+7.3%), seed yield (+22.1%), spike density (+16.6%), and protein (+9.8%) and gluten (+2.1%) contents. The emmer genotypes and the oldest durum wheat ‘Cappelli’ showed the highest protein and gluten contents (mean, 13.9%, 11.2%, respectively). The maximum N agronomic efficiency [AE(N)] and N recovery efficiency [RE(N)] were seen for the modern durum wheat cultivars under 40 kg ha^?1 N treatment: ‘Duilio’, ‘Iride’ and ‘Varano’. The significant correlation between AE(N) and RE(N) and the year of release of the durum wheat cultivars (r = 0.53, P < 0.05, F = 4.7 for AE(N) and r = 0.57, P < 0.01, F = 5.7 for RE(N), respectively; n = 14) showed that the genetic breeding of this species for high grain yield is associated with an increase in the efficiency of N fertiliser use under organic farming. The highly significant effect for the Genotype × Environment interaction (F = 18.1, P < 0.001) of seed yield indicate the possibility to select for stable genotypes across environments. Based on the additive main effects and multiplicative interaction analysis, and the yield stability index, the varieties ‘Iride’ and ‘Varano’ show high‐stability responses and good seed yields under all N fertiliser treatments. Therefore, these varieties can be recommended for organic farming systems in Mediterranean areas.     

Speciation and the “shifting balance” in a continuous population

Shifts between adaptive peaks, caused by sampling drift, are involved in both speciation and adaptation via Wright's “shifting balance.” We use techniques from statistical mechanics to calculate the rate of such transitions for a population in a single panmictic deme and for a population which is continuously distributed over one- and two-dimensional regions. This calculation applies in the limit where transitions are rare. Our results indicate that stochastic divergence is feasible despite free gene flow, provided that neighbourhood size is low enough. In two dimensions, the rate of transition depends primarily on neighbourhood size N and only weakly on selection pressure (≈s^k exp(− cN)), where k is a number determined by the local population structure, in contrast with the exponential dependence on selection pressure in one dimension (≈exp(− cN √s)) or in a single deme (≈exp(− cNs)). Our calculations agree with simulations of a single deme and a one-dimensional population.     

“Ectrogella” Parasitoids of the Diatom Licmophora sp. are Polyphyletic

The diatom genera Licmophora and Fragilaria are frequent epiphytes on marine macroalgae and can be infected by intracellular parasitoids traditionally assigned to the oomycete genus Ectrogella. Much debate and uncertainty remains about the taxonomy of these oomycetes, not least due to their morphological and developmental plasticity. Here, we used single‐cell techniques to obtain partial sequences of the parasitoids 18S and cox2 genes. The former falls into two recently identified clades of Pseudo‐nitzschia parasites temporarily named OOM_1_2 and OOM_2, closely related to the genera of brown and red algal pathogens Anisolpidium and Olpidiopsis. A third group of sequences falls at the base of the red algal parasites assigned to Olpidiopsis. In one instance, two oomycete parasitoids seemed to co‐exist in a single diatom cell; this co‐occurrence of distinct parasitoid taxa not only within a population of diatom epiphytes, but also within the same host cell, possibly explains the ongoing confusion in the taxonomy of these parasitoids. We demonstrate the polyphyly of Licmophora parasitoids previously assigned to Ectrogella (sensu Sparrow, 1960) and show that parasites of red algae assigned to the genus Olpidiopsis are most likely not monophyletic. We conclude that combining single‐cell microscopy and molecular methods is necessary for their full characterisation.     

Rapid detection of “Candidatus Phytoplasma mali” by recombinase polymerase amplification assays

Isothermal recombinase polymerase amplification (RPA) assays for the specific detection of “Candidatus Phytoplasma mali (Ca. P. mali),” the causal agent of apple proliferation, were developed. The assays amplify a fragment of the imp gene and amplimers were detected either by fluorescence in real‐time mode (TwistAmp^®exo assay) using a fluorophore‐labelled probe or by direct visualization employing a lateral flow device (TwistAmp^®nfo assay/Milenia^®HybriDetect). The RPA assays specifically amplified DNA from “Ca. P. mali” strains, and cross‐reactivity with other phytoplasmas or plant DNA was not observed. The limit of detection was determined with a cloned imp standard, and positive results were obtained down to 10 copies with both RPA assay formats. In comparison with a TaqMan real‐time PCR assay based on the same target gene, the RPA assays were equally sensitive, but results were obtained faster. Simplified nucleic acid extraction procedures from plant tissue with Tris‐ and CTAB‐based buffers revealed that crude Tris–DNA extracts were a suitable source for RPA tests while larger concentrations of CTAB were inhibitory. This is the first report of RPA‐based assays for the detection of “Ca. P. mali”. The assays are suitable for high‐throughput screening of plant material and point‐of‐care diagnostic and can be potentially combined with a simplified DNA extraction procedure.     

Proximate Composition and Nutrient Elements in the “Unusual” Algal “Jellies” of Lake Oguta in Southern Nigeria

The proximate composition, nutrient and trace elements of the planktonic algal “jellies” of Lake Oguta in Southern Nigeria, are provided as guides to their utilization and control, using flood (rainy) and dry season samples. These “jellies” are an unusual, macroscopic planktonic algal community in the lake, made up mostly of blue-green algae (Microcystis, Anabaena, Chroococcus) with some green algae (e. g. Spirogyra) and pennate diatoms (e.g. Navicula) rather epiphytic on the mucous jellies of the blue-green algae. Water content was high (98.2% mean, range 97.5-99.5%). Ash, protein and fat had values of 41.7 (39.0-46.2%), 16.9 (15.6-19.4%), and 2.0 (1.7-2.1%) respectively. Crude fibre and carbohydrates were high (25.8% and 12.4%). The levels of phosphorus and nitrogen were rather high, so were the major cations whose order of dominance (Ca > K > Mg > Na) differed from that of the lake water. Macronutrients increased in their concentrations during the rainy flood season while the reverse was the case with the micronutrients. Diagenesis of the endogenic minerals rather than anthropogenic factors are thought to be the reason for the seasonal changes in the ionic concentrations. Possible uses of the algal jellies are discussed as well as their control options.     

Acid dissociation constants and pH values for standard “bes” and “tricine” buffer solutions in 30, 40, and 50 mass% dimethyl sulfoxide/water between 25 and −25 °C

Information is given concerning two standard buffer solutions suitable as pH references in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H₂O mixed solvents at subzero temperatures from −20 to 0 °C, with the intention of establishing a pH (designated pH^*) scale. The two buffers selected were the ampholytes N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (“bes”) and N-tris(hydroxymethyl)methylglycine (“tricine”), and the reference standard consisted of equal molal quantities of the buffer and its respective sodium salt. The assignment of pH^* values was based on measurements of the emf of cells without liquid junction of the type: Pt;H₂(g,1 atm) ¦Bes, Na Besate, NaCl ¦ AgCl;Ag and Pt;H₂(g,1 atm) ¦Tricine, Na Tricinate, NaCl ¦AgCl;Ag and the pH^* was derived from a determination of K₂, the equilibrium constant for the dissociation process (Buffer)^±/ai (Buffer)⁻ + H⁺.     

Heterogeneous Single Atom Electrocatalysis,Where “Singles” Are “Married”

There is an intensive search for heterogeneous single atom catalysts (SACs) of high activity, efficiency, durability, and selectivity for a wide variety of electrocatalytic conversion and chemical reactions, such as the hydrogen evolution reaction (HER), oxygen evolution/reduction reaction (OER and ORR), CO₂ reduction reaction (CO₂ RR), and nitrogen reduction reaction (NRR). With the downsizing from nanoparticles and clusters to single atoms, there are steady changes in the bond and coordination environment for each and every atom involved. Indeed, the single atoms in these electrocatalysts are not “singles”; they are “married” to the supporting surfaces, and their performance is controlled by the bonding and coordination with the substrate surfaces. Herein, an overview is presented on the brief history leading to the rapid development of SACs and their current status, by focusing on their synthesis, control of composition, strategies to realize single atoms with the desired bonds and coordination, and targeted performance in selected reactions. Their applications in the selected spectrum of energy conversion and chemical reactions are discussed, in relation to their structures at varying length scales down to the atomic level. A particular emphasis is placed on on‐going research activities, together with the future perspectives and particular challenges for SACs.