Complement factor 9 deficiency in serum of human neonates.

The serum concentration of complement factor C9 (C9) was 260 +/- 47 micrograms/ml (+/- SE) in 14 mothers and less than 42 micrograms/ml in each of their 14 neonates. During incubation for 60 min, 11 of 14 maternal sera and 3 of 14 neonatal sera reduced the survival of Escherichia coli O7w:K1:NM to less than 20% of the original inoculum (P less than .03). Eleven neonatal sera did not kill the bacteria. Supplemental C9 (60 micrograms/ml) enhanced the bactericidal capacity of 10 neonatal sera. 125I-labeled C9 was deposited onto E. coli by neonatal sera, but less efficiently than by pooled adult sera. Supplemental IgG enhanced 125I-labeled C9 deposition and potentiated the bactericidal activity of exogenous C9. Therefore, neonatal sera contained diminished concentrations of C9 and killed E. coli inefficiently. In neonatal sera, supplemental C9 was deposited onto E. coli and enhanced bactericidal activity. These effects of C9 were potentiated by supplemental IgG.

A cyanobacterium capable of swimming motility.

A novel cyanobacterium capable of swimming motility was isolated in pure culture from several locations in the Atlantic Ocean. It is a small unicellular form, assignable to the genus Synechococcus, that is capable of swimming through liquids at speeds of 25 micrometers per second. Light microscopy revealed that the motile cells display many features characteristic of bacterial flagellar motility. However, electron microscopy failed to reveal flagella and shearing did not arrest motility, indicating that the cyanobacterium may be propelled by a novel mechanism.

Comparison of the Limulus amoebocyte lysate test with plate counts and chemical analyses for assessment of the quality of lean fish.

The quality of lean fish was assessed simply and rapidly with Limulus amoebocyte lysate. The endotoxin levels agreed with aerobic plate counts and chemical indices of spoilage. Correlation between level of endotoxin and level of total volatile bases was found to be highly significant (r = 0.8579; P less than 0.001).

Dental considerations in the sublabial trans-sphenoidal surgical approach to the pituitary gland.

The sublabial trans-sphenoidal approach for the ablation of pituitary tumors can cause denervation or pulp death of some of the anterior teeth. The problem results from the bone removal necessary for placement of the nasal retractor. When bone is removed close to the apices of the anterior teeth, root injury may occur. This complication may be avoided through preoperative evaluation of skeletal and dental morphology. This evaluation reveals the amount of bone between the tooth roots and the nasal floor and hence the ultimate access for the nasal retractor.

Production of NO(2) and N(2)O by Nitrifying Bacteria at Reduced Concentrations of Oxygen.

Pure cultures of the marine ammonium-oxidizing bacterium Nitrosomonas sp. were grown in the laboratory at oxygen partial pressures between 0.005 and 0.2 atm (0.18 to 7 mg/liter). Low oxygen conditions induced a marked decrease in the rate for production of NO(2), from 3.6 x 10 to 0.5 x 10 mmol of NO(2) per cell per day. In contrast, evolution of N(2)O increased from 1 x 10 to 4.3 x 10 mmol of N per cell per day. The yield of N(2)O relative to NO(2) increased from 0.3% to nearly 10% (moles of N in N(2)O per mole of NO(2)) as the oxygen level was reduced, although bacterial growth rates changed by less than 30%. Nitrifying bacteria from the genera Nitrosomonas, Nitrosolobus, Nitrosospira, and Nitrosococcus exhibited similar yields of N(2)O at atmospheric oxygen levels. Nitrite-oxidizing bacteria (Nitrobacter sp.) and the dinoflagellate Exuviaella sp. did not produce detectable quantities of N(2)O during growth. The results support the view that nitrification is an important source of N(2)O in the environment.

Determination of bacterial number and biomass in the marine environment.

Three techniques for the measurement of bacterial numbers and biomass in the marine environment are described. Two are direct methods for counting bacteria. The first employs an epifluorescence microscope to view bacteria that have been concentrated on membrane filters and stained with acridine orange. The second uses a transmission electron microscope for observing replicas of bacteria that are concentrated on membrane filters. The other technique uses Limulus amebocyte lysate, an aqueous extract from the amebocytes of the horseshoe crab, Limulus polyphemus, to quantitate lipopolysaccharide (LPS) in seawater samples. The biomass of gram-negative (LPS containing) bacteria was shown to be related to the LPS content of the samples. A factor of 6.35 was determined for converting LPS to bacterial carbon.

Inhibitory effect of heparin on the Limulus test for endotoxin.

Heparin can inhibit the Limulus test for endotoxin unless 0.05 M CaCl(2) and 0.154 M NaCl are added to the lysate.

Influence of substrate wettability on the attachment of marine bacteria to various surfaces.

The effect of the initial substrate surface condition, as indicated by the critical surface tension for wetting, on the rate of attachment of marine bacteria to a variety of solid surfaces has been measured. The techniques used to determine the number of bacteria attached per unit surface area were a lipopolysaccharide test utilizing Limulus lysate and direct examination of the surface by scanning electron microscopy. The results obtained by the two techniques are compared and their significance to the control of microbiological slime film formation (microfouling) is discussed.

Factors affecting the sensitivity of Limulus lysate.

Limulus lysate clots when mixed with picogram quantities of endotoxins. The sensitivity of the lysate was improved 100-fold by the removal of an inhibitor and addition of divalent cations. The methods developed in this investigation eliminated much of the seasonable variability of the lysate, improved the heat stability after lyophilization, and made it possible to use the lysate with saline solutions.

Protein and carbohydrate composition of the cell envelope of Halobacterium salinarium.

The isolated cell envelope of Halobacterium salinarium strain 1 contained 15 to 20 proteins that were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. All but one of these proteins had molecular weights of 130,000 or less and together accounted for 50 to 60% of the total envelope protein. The remaining 40 to 50% of the envelope protein was accounted for by a single protein with an apparent molecular weight of approximately 194,000 that stained for carbohydrate with periodate-Schiff reagent. The proteolytic enzymes trypsin and Pronase were used to show that the carbohydrate is covalently bound to the protein. Separation of amino sugar- and hexose-containing tryptic peptides by gel filtration indicated that all of the nonlipid carbohydrate of the cell envelope is covalently bound to protein. The results of partial purification by phenol extraction indicated that both the amino sugar and hexose are bound to the 194,000-molecular-weight protein. Exposure of isolated cell envelopes to low salt concentration resulted in solubilization of a majority of the envelope proteins. A relatively small number of proteins, including the high-molecular-weight, carbohydrate-containing protein, remained bound to the sedimentable cell membrane fraction.

Factors affecting interaction of staphylococcal alpha toxin with membranes.

Staphylococcal alpha toxin interacts not only with membranes of erythrocytes but also with membranes of other kinds of mammalian cells (platelets, hepatocytes, and lysosomes from polymorphonuclear leukocytes) with the formation of characteristic ring-like structures that can be seen by electron microscopy. Such structures are not observed when alpha toxin is added to membranes derived from various bacteria. The rings seen on mammalian cell membranes tend to be either randomly disposed or in square array. The frequency with which square arrays are seen is influenced by the presence of staphylococcal delta toxin, by the negative staining agent, and by the kind of cell from which the membrane is derived. Synthetic membranes in the form of liposomes, prepared individually from phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol, and cardiolipin, produced randomly disposed rings upon addition of alpha toxin. Liposomes made from phosphatidyl ethanolamine did not yield rings. Alpha toxin-treated liposomes prepared from chloroform-methanol extracts of brain white matter consistently showed rings that were rectangularly ordered. Ordered rings on membranes derived from toxin-treated platelets and those on toxin-treated brain extract liposomes were seen in freeze-etched as well as in negatively stained preparations.

Comparison of the morphology and deoxyribonucleic acid composition of 27 strains of nitrifying bacteria.

The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid GC compositions. Similarly, the nitrite-oxidizing bacteria were separated into three genera based on their morphology. The members of two of these nitrite-oxidizing genera, Nitrobacter and Nitrococcus, had similar GC compositions, but Nitrospina gracilis had a significantly lower GC composition than the members of the other two genera.