Resonance Raman spectra of vitamin B12 and dicyanocobalamin

The Raman spectra of cyanocobalamin (vitamin B12) and dicyanocobinamide have been obtained from aqueous solutions at concentrations of approx. 1 10⁻⁴ M. The spectra were excited by laser radiation coincident in wavelength with the visible absorption, this resulting in selective enhancement of some vibrational modes through the rigorous resonance Raman effect. In spite of substantial chemical differences, cyanocobalamin and dicyanocobinamide give essentially identical spectra, indicating that only those modes associated with the common corrin ring system are resonance enhanced.     

Structural chromosome abnormalities in Down syndrome: a study of two families.

Two families were ascertained through a proband with Down syndrome and a structural rearrangement involving two chromosomes 21. It is suggested that in one patient the chromosome is an isochromosome formed by misdivision of the centromere of a maternal telocentric chromosome 21 and that in the other a Robertsonian translocation involving chromosome 21 was inherited from the mother, who is a 46,XX/46,XX, -21,+t(21q21q) mosaic. The origin of the mosaicism is discussed and considered to be likely to be the result of breakage and reunion at the chromatid, rather than the chromosome, level.     

Effects of chemical combinations on the induction of aneuploidy in Saccharomyces cerevisiae

Nocodazole, ethyl acetate, acetone and methyl ethyl ketone all are known to induce aneuploidy. Treatment of yeast strain D61.M with mixtures containing ineffective low levels of nocodazole and ineffective low levels of these solvents was highly effective in inducing aneuploidy. Ineffective low levels of nocodazole mixed with ineffective low levels of methyl 2-benzimidazolecarbamate also gave elevated frequencies of aneuploidy. Dimethyl formamide, a solvent that does not induce aneuploidy, mixed with low levels of nocodazole gave no increase in aneuploidy frequency above those levels seen in controls.     

Bioklimatische Unterschiede zwischen einer Stadt- und einer Waldatmosphäre

From data of meteorological stations in a city (Munich) and in a forest (Ebersberger Forst, near Munich) for the summer months 1972 mean monthly diurnal variations of the following parameters were computed: vapour pressure, equivalent temperature, effective temperature, energy consumption with respiration and hourly water requirement for saturation of the respiratory air. The results show that during the summer season forest air is bioclimatically more comfortable than city air for humans.     

Recovery of fish and crustacean communities during remediation of tidal wetlands affected by leachate from acid sulfate soils in north-eastern Australia

In the 1970s, acid sulfate soils (ASS) distributed within about 720 ha of predominantly mangrove and salt pan wetlands at East Trinity in north Queensland were developed after the area was isolated from tidal flooding by a surrounding seawall and the installation of tidal gates on major drainage creeks. Following drainage and oxidation of these estuarine acidic sediments, resultant acid leachate caused considerable, ongoing environmental problems including regular fish kills. A rehabilitation program covering much of these former tidal wetlands commenced in 2000 using a lime-assisted tidal exchange management regime. Changes in the established populations of estuarine fish and crustaceans were monitored in the two creeks (Firewood and Hills Creeks) where tidal flows were reinstated. In Firewood Creek between 2001 and 2005, there was a progressive increase in fish species richness, diversity and abundance. The penaeid prawn Fenneropenaeus merguiensis was a major component of the cast net catches in the lower sections of both Firewood and Hills Creeks but its relative abundance decreased upstream of the tidal gates on the seawall. Well established stocks of predominantly juvenile, male Scylla serrata resident upstream of the tidal gates indicated suitable habitats with acceptable water and sediment quality and adequate availability of food. The regular fish kills that occurred prior to the management regime abated and, overall, the implementation of the rehabilitation program is yielding positive benefits for the local fisheries.     

Do People “Pop Out”?

The human body is a highly familiar and socially very important object. Does this mean that the human body has a special status with respect to visual attention? In the current paper we tested whether people in natural scenes attract attention and “pop out” or, alternatively, are at least searched for more efficiently than targets of another category (machines). Observers in our study searched a visual array for dynamic or static scenes containing humans amidst scenes containing machines and vice versa. The arrays consisted of 2, 4, 6 or 8 scenes arranged in a circular array, with targets being present or absent. Search times increased with set size for dynamic and static human and machine targets, arguing against pop out. However, search for human targets was more efficient than for machine targets as indicated by shallower search slopes for human targets. Eye tracking further revealed that observers made more first fixations to human than to machine targets and that their on-target fixation durations were shorter for human compared to machine targets. In summary, our results suggest that searching for people in natural scenes is more efficient than searching for other categories even though people do not pop out.     

Brucella abortus 16S rRNA and lipid A reveal a phylogenetic relationship with members of the alpha-2 subdivision of the class Proteobacteria

On the basis of ribosomal 16S sequence comparison, Brucella abortus has been found to be a member of the alpha-2 subdivision of the class Proteobacteria (formerly named purple photosynthetic bacteria and their nonphototrophic relatives). Within the alpha-2 subgroup, brucellae are specifically related to rickettsiae, agrobacteria, and rhizobiae, organisms that also have the faculty or the obligation of living in close association to eucaryotic cells. The composition of Brucella lipid A suggests a close phylogenetical relationship with members of the alpha-2 group. The chemical analysis of the lipid A fraction revealed that Brucella species contain both glucosamine and diaminoglucose, thus suggesting the presence of a so-called mixed lipid A type. The serological analysis with polyclonal and monoclonal antibodies is in agreement with the existence of mixed lipid A type in B. abortus. The amide-linked fatty acid present as acyl-oxyacyl residues were 3-O-C(16:0)12:0, 3-O-C(16:0)13:0, 3-O-C(16:0)14:0, and 3-O-C(18:0)14:0. The only amide-linked unsubstituted fatty acid detected was 3-OH-C16:0. The ester-linked fatty acids are 3-OH-C16:0, 3-OH-C18:0, C16:0, C17:0, and C18:0. Significant amounts of the large-chain 27-OH-C28:0 were detected together with traces of 25-OH-C26:0 and 29-OH-C30:0. Comparison of the Brucella lipid composition with that of the other Proteobacteria also suggests a close phylogenetical relationship with members of the alpha-2 subdivision. The genealogical grouping of Brucella species with pericellular and intracellular plant and animal pathogens as well as with intracellular plant symbionts suggests a possible evolution of Brucella species from plant-arthropod-associated bacteria.