Populations of Anaerobic Phototrophic Bacteria in a Spartina alterniflora Salt Marsh

Habitat-simulating media were used with the Hungate anaerobic roll tube technique to enumerate culturable anaerobic photosynthetic bacteria in sediment, tidal waters, and Spartina alterniflora plant samples collected from the salt marsh at Sapelo Island, Ga. No phototrophs were detected in samples of creekside (low marsh) sediment or in tidal waters in creekside regions. In the high marsh region, 90% of anaerobic phototrophic bacteria occurred in the top 5 mm of sediment and none were detected below 6 mm. There was a seasonal variation, with maximal populations occurring in summer and fall (mean, 4.4 × 10⁵ phototrophs g of dry sediment⁻¹) and minimal numbers occurring in winter (mean, 3.9 × 10³ phototrophs g of dry sediment⁻¹). During winter and late spring, phototrophs had a patchy distribution over the high marsh sediment surface. In contrast, during late summer they had a random uniform distribution. Tidal water collected over high marsh sediment contained an average of 8.7 × 10² phototrophs ml⁻¹, with no significant seasonal variation. Anaerobic phototrophic bacteria were also cultured from the lower stem tissue of S. alterniflora growing in both the high (4.3 × 10⁴ phototrophs g of dry tissue⁻¹) and creekside (4.9 × 10⁴ phototrophs g of dry tissue⁻¹) marsh regions. Chromatium buderi, Chromatium vinosum, Thiospirillum sanguineum, Rhodospirillum molischianum, and Chlorobium phaeobacteroides were the predominant anaerobic phototrophic species cultured from high marsh sediment. The two Chromatium species were dominant.     

The genetics and expression of an esterase locus inAnopheles gambiae

The main polymorphic system of esterase isoenzymes in adults of the G3 laboratory strain ofAnopheles gambiae consists of two to five major bands of activity per individual. The bands are designated 5S, 5F, 13, 14, and 15. In genetic crosses, the genes which coded for the bands assorted as three codominant alleles, Est A, Est B, and Est C, at a single autosomal locus. Homozygotes for the Est C allele were significantly underrepresented among backcross progeny. The developmental pattern of esterase expression was examined. Esterase gene expression in embryos was first detectable between 2 and 12 hr after oviposition. The initiation or termination of expression of some of the bands corresponded to boundaries between developmental stages. Most of the esterase fractions were not specifically localized within the tissues tested, with the exception of a series of bands which were restricted largely to adult male testes.     

Purification and characterization of cytoplasmic creatine kinase isozymes ofXenopus laevis

The soluble creatine kinase isozymes CK-II, CK-III, and CK-IV fromXenopus laevis have been purified to apparent homogeneity and their subunits characterized by means of molecular weight, peptide pattern, and dissociation-reassociation experiments. CK-III and CK-IV are homodimeric isozymes whose subunits are distinct in both molecular weight (42,000 and 41,000, respectively) andStaphylococcus aureus V₈ peptide pattern. In dissociation-reassociation experiments, those two subunits do form active heterodimeric isozymes with one another or with rabbit M-CK subunits. Hybrid CK-III/IV isozymes occur also during embryonic differentiation and in adult heart muscle, whereas most other adult tissues contain only homodimeric CK-III or CK-IV isozymes. The CK-II isozyme is a heterodimer composed of one CK-III subunit and another subunit specific to CK-II (M _r =41,000). Neitherin vivo norin vitro does this subunit seem able to form homodimers or heterodimers with CK-IV and rabbit M-CK subunits. If we take into account the apparent association of CK-I isozyme with cellular organelles, these results corroborate earlier statements and suggest that the CK isozyme system ofX. laevis is encoded by at least four differentially regulated genomic loci.     

Vernonia galamensis,Potential new crop source of epoxy acid

Vernonia galamensis is a good source of seed oil rich in epoxy acid, which can be used to manufacture plastic formulations, protective coatings, and other products. Seed from a natural stand in Ethiopia contained 31% epoxy acid. Under cultivation in Kenya, this unimproved germplasm produced a substantial yield of seed with 32% epoxy acid. This African species has good natural seed retention and is a promising new crop for semiarid tropical areas.     

Genealogy of Principal Strains of the Yeast Genetic Stock Center

We have constructed a genealogy of strain S288C, from which many of the mutant and segregant strains currently used in studies on the genetics and molecular biology of Saccharomyces cerevisiae have been derived. We have determined that its six progenitor strains were EM93, EM126, NRRL YB-210 and the three baking strains Yeast Foam, FLD and LK. We have estimated that approximately 88% of the gene pool of S288C is contributed by strain EM93. The principal ancestral genotypes were those of segregant strains EM93-1C and EM93-3B, initially distributed by C. C. Lindegren to several laboratories. We have analyzed an isolate of a lyophilized culture of strain EM93 and determined its genotype as MATa/MATα SUC2/SUC2 GAL2/gal2 MAL/MAL mel/mel CUP1/cup1 FLO1/flo1. Strain EM93 is therefore the probable origin of genes SUC2, gal2, CUP1 and flo1 of S288C. We give details of the current availability of several of the progenitor strains and propose that this genealogy should be of assistance in elucidating the origins of several types of genetic and molecular heterogeneities in Saccharomyces.     

Evaluation of Diverse Antisera, Conjugates, and Support Media for Detecting Bradyrhizobium japonicum by Indirect Enzyme-Linked Immunosorbent Assay

We evaluated three antisera and four enzyme conjugates for the detection of Bradyrhizobium japonicum by an indirect enzyme-linked immunosorbent assay in microtiter plates. Nitrocellulose membrane sheets were then evaluated as an alternative support medium by using some combinations. Partially purified immunoglobulin G (IgG) or unpurified antisera to strain USDA 110 raised in rabbits, goats, or sheep was reacted in microtiter plates with alkaline phosphatase conjugated to protein A, goat anti-rabbit (GAR), sheep anti-rabbit (SAR), or rabbit anti-goat (RAG) IgG. Cultures or nodules containing homologous rhizobia were detected with equal sensitivity when protein A, GAR, or SAR was reacted with 5 μg of protein IgG per ml or a 1:800 titer of antisera from rabbits, but not goats or sheep. RAG reacted with IgG or antisera from goats or sheep. The detection limit was 2 × 10⁵ rhizobia per well. Rhizobia were spotted on nitrocellulose sheets as an alternative support medium, followed by soaking in 5 μg of protein per ml as IgG and 1:4,000 dilutions of protein A or GAR conjugate. Rhizobia in serogroup 110 were detected with the dye combination Nitro Blue Tetrazolium-5-bromo-4-chloro-3-indolyl phosphate (NBT-BCIP), and rhizobia in serogroup 122 were detected with fast red-naphthol phosphate (FR-NP). At the conclusion of the 5-h assay, purple (NBT-BCIP) or red (FR-NP) spots were visible in positive reactions. The sensitivity of detection was about 1,000 rhizobial cells or 3 μg of nodules tissue.     

Improved Method of Typing Bradyrhizobium japonicum in Soybean Nodules

An improved method for antibiotic resistance recovery of Bradyrhizobium japonicum from soybean (Glycine max (L.) Merr.) nodules that is simple, time saving, and economical was developed. This technique involves the use of two 96-well microtiter plates as a multinodule sterilization chamber and a template and a third plate as a 16-point replicator constructed with steel nails affixed to the plate with epoxy cement. With this system a team of four technicians could type 3,000 nodules per day. This method was useful in assessing strain establishment and interstrain competition when one or more uniquely labeled strains of B. japonicum were inoculated onto either growth-room- or field-grown soybeans. Contamination was low and reproducibility across replicates approached the theoretical upper limit. Simplicity in design and use made this recovery method especially adaptable for field studies in which large numbers of nodules were required to provide a representative statistical sample offering good precision.     

Inhibitory Effect of Autoclaving Whey-Based Medium on Propionic Acid Production by Propionibacterium shermanii

Propionic acid production by Propionibacterium shermanii was compared in pasteurized and autoclaved whey-based media. Propionic acid production decreased with increasing whey concentration in autoclaved media but not in pasteurized media. Increasing the yeast extract concentration from 5 to 10 g/liter greatly reduced the inhibitory effect of autoclaving.     

Production of High-Viscosity Whey-Glucose Broths by a Xanthomonas campestris Strain

Acclimation of a sandy soil to an air-natural gas mixture stimulated the biological oxidation of chloroform to carbon dioxide. Acetylene and methane inhibited chloroform oxidation. Chloroform oxidation continued up to 31 days in the absence of methane. Chloroform oxidation rates increased at chloroform concentrations up to 5 μg g of soil^-1.     

Changes in Insulin Binding to Developing Embryonic Chick Neural Retina Cells

Specific cell surface insulin binding to embryonic chick neural retina cells has been demonstrated in vivo. Kinetics of insulin binding as well as hormonal specificity were similar to those reported for other vertebrate cells and tissues, both neural and nonneural. When surface insulin binding to retinal cells was studied as a function of embryonic age, a developmental relationship was observed. Scatchard analysis revealed that the number of cell surface insulin receptors decreased approximately 75% between days 10 and 16 of embryonic development. Receptor affinities remained fairly constant for this period.