Cloning, sequencing and mutational analysis of the cytochrome c552 gene (cycB) from Bradyrhizobium japonicum strain 110

We report the cloning and nucleotide sequence analysis of the cytochrome c552 gene (cycB) of Bradyrhizobium japonicum strain 110. The gene was identified with help of an oligonucleotide that was designed on the basis of the amino acid sequence determined for purified cytochrome c552 of B. japonicum strain CC705. The cycB gene product has an N-terminal 23-amino acid signal peptide that is missing in the mature cytochrome c552 protein. A B. japonicum cycB insertion mutant was constructed which had no observable phenotypic defects in denitrification and symbiotic nitrogen fixation. Thus, the function of c552 remains unknown.     

The neozoanElminius modestus Darwin (Crustacea, Cirripedia): Possible explanations for its successful invasion in European water

Comparison of data from the literature has provided evidence that eurythermal and euryhaline adaptation of larvae and adults in combination with a long seasonal breeding period, high fecundity and short generation time have givenElminius modestus an, advantage over indigenous cirripede species, allowing a rapid spread throughout European waters.     

O-acetyl-salicylic acid promotes colony formation from protoplasts of an elite maize inbred

The salicylic acid derivative acetylsalicylic acid (ASA) was found to promote colony formation from protoplasts isolated from embryogenic suspension cultures of an elite maize inbred line. The drug was most effective at concentrations of 30–100 mg/l, and increases of more than 20-fold in the number of colonies recovered from protoplasts were obtained. The rate of growth of protoplast-derived cell colonies was not affected.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - DMSO dimethylsulfoxide - KM Kao and Michayluk medium (1975) - MES 2[N-morpholino]ethanesulfonic acid - ASA acetylsalicylic acid     

A strictly anaerobic betaproteobacterium Georgfuchsia toluolica gen. nov., sp. nov. degrades aromatic compounds with Fe(III), Mn(IV) or nitrate as an electron acceptor

A bacterium (strain G5G6) that grows anaerobically with toluene was isolated from a polluted aquifer (Banisveld, the Netherlands). The bacterium uses Fe(III), Mn(IV) and nitrate as terminal electron acceptors for growth on aromatic compounds. The bacterium does not grow on sugars, lactate or acetate. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain G5G6 belonged to the Betaproteobacteria . Its closest, but only distantly related, cultured relative is Sterolibacterium denitrificans Chol-1S^T (94.6% similarity of the 16S rRNA genes), a cholesterol-oxidizing, denitrifying bacterium. Strain G5G6 possesses the benzylsuccinate synthase A ( bssA ) gene encoding the α-subunit of Bss, which catalyzes the first step in anaerobic toluene degradation. The deduced BssA amino acid sequence is closely related to those of Azoarcus and Thauera species, which also belong to the Betaproteobacteria . Strain G5G6 is the first toluene-degrading, iron-reducing bacterium that does not belong to the Geobacteraceae within the Deltaproteobacteria . Based on phylogenetic and physiological comparison, strain G5G6 could not be assigned to a described species. Therefore, strain G5G6 (DSMZ 19032^T=JCM 14632^T) is a novel taxon of the Betaproteobacteria . We propose the name Georgfuchsia toluolica gen. nov., sp. nov.     

Tackling the difficulties in learning evolution: effects of adaptive self-explanation prompts

Teaching and learning evolution is challenging. Biology education research shows that the underlying evolutionary concepts are poorly understood among students. This prevents a meaningful understanding of the central biological concepts. The instructional format of self-explanation prompts seems to be promising to respond to these difficulties. However, previous research has shown that the interaction between prior knowledge and prompts is an important factor in enhancing effective self-explanations. Nevertheless, there are hardly any studies which focus on the majority of learners in the classrooms, ie students with average prior knowledge. The aim of this study was to analyse the requirements of adaptive self-explanation prompts specifically for these learners. This should enable students at all knowledge levels to be effectively fostered in self-explaining, while they are learning evolution. We investigated the effects of three kinds of prompts for fostering self-explanations: learners with average prior knowledge were prompted with low or/and high-knowledge prompts. Our analysis of 22 verbal protocols by middle-school German students shows that the prompts evoked the intended self-explanations. The most positive impact with regard to self-explanation quality was created by the prompting condition which combines low-knowledge and high-knowledge self-explanation characteristics.     

Collpas: Activity Hotspots for Frugivorous Bats (Phyllostomidae) in the Peruvian Amazon

In the SE Peruvian Amazon, large numbers of frugivorous bats regularly visit natural forest clearings known locally as collpas (which are also referred to as clay licks or mineral licks). Bats arrive at collpas to drink water that has accumulated in depressions created by larger geophagous mammals that consume exposed soil. Although collpa visitation is common, little is known about its causes and its ecological implications for the bat community. We compared patterns of use of collpas and non- collpa forest sites by bats in SE Peru. We mist netted bats at collpas and non- collpa sites during the dry season and compared abundance, species richness, species composition, sex ratio, and reproductive condition. More species were captured at collpas than at non- collpa sites, and collpas were visited almost exclusively by frugivores. Overall, bat-capture frequency and combined frugivorous bat-capture frequency were higher at collpas than at non- collpa sites, although some species of frugivorous bats were captured more frequently at non- collpa sites than at collpas ( e.g ., Carollia spp.). Irrespective of capture site, more female bats were pregnant or lactating than not, but there was a distinct female sex bias in bats that visited collpas : 70 percent of bats captured at collpas were female, whereas 44 percent of bats captured away from collpas were female. These patterns suggest that collpas may provide important resources for frugivorous bats in SE Peru, just as they are thought to provide important resources to the vertebrates that consume collpa soils. Accordingly, collpas are important conservation targets in the region.     

A catalytic role for threonine-12 of E. coli asparaginase II as established by site-directed mutagenesis

A threonine-12 to alanine mutant of E. coli asparaginase II (EC 3.5.1.1) has less than 0.01% of the activity of wild-type enzyme. Both tertiary and quaternary structure of the enzyme are essentially unaffected by the mutation; thus the activity loss seems to be the result of a direct impairment of catalytic function. As aspartate is still bound by the mutant enzyme, Thr-12 appears not be involved in substrate binding.     

Normothermia after decompressive surgery for space-occupying middle cerebral artery infarction: a protocol-based approach

Background

Moderate hypothermia after decompressive surgery might not be beneficial for stroke patients. However, normothermia may prove to be an effective method of enhancing neurological outcomes. The study aims were to evaluate the application of a pre-specified normothermia protocol in stroke patients after decompressive surgery and its impact on temperature load, and to describe the functional outcome of patients at 12 months after treatment.

Methods

We analysed patients with space-occupying middle cerebral artery (MCA) infarction treated with decompressive surgery and a pre-specified temperature management protocol. Patients treated primarily with device-controlled normothermia or hypothermia were excluded. The individual temperature load above 36.5 °C was calculated for the first 96 h after hemicraniectomy as the Area Under the Curve, using °C x hours. The effect of temperature load on functional outcome at 12 months was analysed by logistic regression.

Results

We included 40 stroke patients treated with decompressive surgery (mean [SD] age: 58.9 [10.1] years; mean [SD] time to surgery: 30.5 [16.7] hours). Fever (temperature?>?37.5 °C) developed in 26 patients during the first 96 h after surgery and mean (SD) temperature load above 36.5 °C in this time period was 62,3 (+/? 47,6) °C*hours. At one year after stroke onset, a moderate to moderately severe disability (modified Rankin Scale score of 3 or 4) was observed in 32% of patients, and a severe disability (score of 5) in 37% of patients, respectively. The lethality in the cohort at 12 months was 32%. The temperature load during the first 96 h was not an independent predictor for 12 month lethality (OR 0.986 [95%-CI:0.967–1.002]; p?<?0.12).

Conclusions

Temperature control in surgically treated patients with space-occupying MCA infarction using a pre-specified protocol excluding temperature management systems resulted in mild hyperthermia between 36.8 °C and 37.2 °C and a low overall temperature load. Future prospective studies on larger cohorts comparing different strategies for normothermia treatment including temperature management devices are needed.

     

Guest research facilities at the Biologische Anstalt Helgoland: Past and present

The Biologische Anstalt Helgoland (BAH) offers unique possibilities for research and education in marine sciences in the southern part of the North Sea. Besides its own research duties, the Institute provides research facilities and technical assistance for guest scientists, assists in the teaching and education of university student groups, and conducts its own courses. The Institute further supplies universities and research institutions on the mainland with marine organisms. The marine station on Helgoland has 14 laboratories, with a total of 32 working places available for guest scientists. The Wadden Sea Institute in List on the island of Sylt offers 6 laboratories with a total of 18 working places. Furthermore, laboratory classrooms are located on Helgoland and in List for 50 and 20 participants, respectively. For the convenience of the guest researchers staying at the BAH, guest-houses are run on Helgoland (Arthur-Hagmeier-Haus, Wilhelm-Mielk-Haus) und in List (Adolf-Bückmann-Haus). Guest researchers have been welcome since the founding of the Institute in 1892. Heincke gave a brief report on the activities of the first visitors from 1892 to 1897. Only sporadic reports are available for the first 60 years of this century. Guest scientists and their activities have only been recorded in detail in the annual reports of the BAH since 1962. The number of researchers and the length of their visits have increased continuously since 1962. The research facilities on Helgoland, in List and Hamburg have been modernized during the last 20 years. In 1971, four modern laboratories for guest researchers could be opened on Helgoland with financial support of the German Research Foundation (DFG). The number, of guest researchers in List and Hamburg increased after the completion of new buildings in 1979 and 1982. The recent increase in research activities by guest scientists is due to numerous students, from many different universities, using the superb research facilities to do their Masters thesis, or Ph.D. Guest researchers and students either perform their own research or cooperate with scientists of the BAH.     

Staphylococcus aureus Alpha-Toxin Mediates General and Cell Type-Specific Changes in Metabolite Concentrations of Immortalized Human Airway Epithelial Cells

Staphylococcus aureus alpha-toxin (Hla) is a potent pore-forming cytotoxin that plays an important role in the pathogenesis of S. aureus infections, including pneumonia. The impact of Hla on the dynamics of the metabolome in eukaryotic host cells has not been investigated comprehensively. Using ¹H-NMR, GC-MS and HPLC-MS, we quantified the concentrations of 51 intracellular metabolites and assessed alterations in the amount of 25 extracellular metabolites in the two human bronchial epithelial cell lines S9 and 16HBE14o⁻ under standard culture conditions and after treatment with sub-lethal amounts (2 µg/ml) of recombinant Hla (rHla) in a time-dependent manner. Treatment of cells with rHla caused substantial decreases in the concentrations of intracellular metabolites from different metabolic pathways in both cell lines, including ATP and amino acids. Concomitant increases in the extracellular concentrations were detected for various intracellular compounds, including nucleotides, glutathione disulfide and NAD⁺. Our results indicate that rHla has a major impact on the metabolome of eukaryotic cells as a consequence of direct rHla-mediated alterations in plasma membrane permeability or indirect effects mediated by cellular signalling. However, cell-specific changes also were observed. Glucose consumption and lactate production rates suggest that the glycolytic activity of S9 cells, but not of 16HBE14o⁻ cells, is increased in response to rHla. This could contribute to the observed higher level of resistance of S9 cells against rHla-induced membrane damage.