The viking carbon assimilation experiments: interim report

A synthesis of organic matter from atmospheric carbon monoxide or carbon dioxide, or both, appears to take place in the surface material of Mars at a low rate. The synthesis appears to be thermolabile and to be inhibited by moisture.     

Dehalogenation: a novel pathway for the anaerobic biodegradation of haloaromatic compounds

Microorganisms of lake sediment and sewage sludge anaerobically metabolized halobenzoates by a novel pathway. The primary degradative event was loss of the aryl halide without the alteration of the aromatic ring. Dehalogenation required strict anaerobic conditions and depended on the halogen and position, but not the number of halogen substituents. A stable methanogenic bacterial consortium was enriched from sludge and found capable of dehalogenating and often mineralizing a variety of halobenzoates to CH(4) and CO(2). The results suggest that reductive dehalogenation of aromatics could be important in removal of some chlorinated xenobiotics from the environment.     

The effect of membrane filtration on dissolved trace element concentrations

The almost universally accepted operational definition for dissolved constituents is based on processing The almost universally accepted operational definition for dissolved constituents is based on processing whole-water samples through a 0.45-μm membrane filter. Results from field and laboratory experiments indicate that a number of factors associated with filtration, other than just pore size (e.g., diameter, manufacturer, volume of sample processed, amount of suspended sediment in the sample), can produce substantial variations in the ‘disolved’ concentrations of such elements as Fe, Al, Cu, Zn, Pb, Co, and Ni. These variations result from the inclusion/exclusion of colloidally-associated trace elements. Thus, 'dissolved' concentrations quantitated by analyzing filtrates generated by processing whole-water through similar pore-sized membrane filters may not be equal/comparable. As such, simple filtration through a 0.45-μm membrane filter may no longer represent an acceptable operational definition for dissolved chemical constituents. This conclusion may have important implications for environmental studies and regulatory agencies.     

Adsorption of cadmium to kaolinite in the presence of organic material

Kaolinite was equilibrated with Cd and with varying amounts of the individual compounds: EDTA, NTA, alginic acid, and humic acid. In experiments in which the Cd and kaolinite concentrations were held constant, and the ligand concentration allowed to vary, conditions under which ligand enhanced and inhibited Cd association with the solid phase were noted. Further experiments at constant Cd: ligand confirmed that, for alginic acid and humic acid, enhancement of uptake occurred, while EDTA diminished uptake. These results were compared with the adsorption of ligand by clay in the absence of organic, and it is suggested that the enhancement of uptake is due to the formation of an adsorbed organic layer on the clay serving as a solid phase ligand.     

A study of articular surfaces and synovial fossae of the pectoral limb of swine.

Articular surfaces of the pectoral limb were studied in 50 swine and are described in detail. Synovial fossae were not present at birth but were found commonly on the articular surface of the scapula, distal humerus, proximal radius, distal radius and distal surfaces of the intermediate carpal bone after four to five months of age. When present, they were bilaterally symmetrical and were located at the depth of a concavity of the articular surface. Microscopically, synovial fossae appeared as an invagination of articular cartilage extending into subchondral bone. Evidence of endochondral bone formation was less apparent at the depth of synovial fossae than in areas of weight bearing cartilage.     

Joint action of Beauveria bassiana and the insect growth regulators diflubenzuron and novaluron, on the migratory locust, Locusta migratoria

Beauveria bassiana (Balsamo) Vuillemin and sublethal concentrations of the insect growth regulators (IGR) diflubenzuron and novaluron were applied simultaneously and sequentially to second-instar Locusta migratoria migratorioides (Sauss.) to determine the interaction between these materials and an entomopathogenic fungus. Nymphs were fed on corn leaf disks treated with several concentrations of each IGR, and a constant dose of B. bassiana was applied topically. Additive interaction was demonstrated in all instances when second-instar nymphs were exposed to diflubenzuron or novaluron simultaneously with B. bassiana treatment, and when the fungus was applied first and IGR after 48 h. Additive interaction was also exhibited when novaluron was applied first and B. bassiana after 48 h. Antagonism was demonstrated when nymphs were fed diflubenzuron-treated corn leaves first, then after 48 h were treated with B. bassiana. The additive interaction that was observed in our experiments could still be useful to achieve efficacious levels of acridid control at low rates of an IGR along with a biological control agent such as an entomopathogenic fungus.