A study was conducted to determine the influence of a bio-organic amendment 'Greens Restore' (6N-1P-3K) and a nitrogen fertilizer (21N-7P-14K) on the microbial numbers, thatch degradation, and soil respiration. A complete randomized block design was used with 3 treatments/4 replications. Both treatments were applied at a rate of 28.6 kg N/ha every 60 and 30 days for the first and second year respectively. No significant changes were observed due to treatments for all the parameters measured except for soil fungi and thatch thickness. Control plots had the lowest and the fertilized plots had the highest values for both parameters. Microbial numbers showed significant differences with time except for the denitrifiers. Thatch bacterial, fungal, and actinomycetes numbers were greater than in soil. Two peaks in microbial numbers and soil respiration occurred in spring and autumn. Soil pH also changed with time and peaked in spring and autumn.

Samples of imported shrimp from China, Ecuador, and Mexico were obtained from wholesale and retail markets, and aerobic plate counts (APC) using four temperature/salinity regimes, frequency of Listeria spp. and Vibrio spp. contamination, and antibiotic resistance patterns of Vibrio spp. were determined. Significant differences in APC were observed only between country and wholesale versus retail samples. Wholesale shrimp products were consistently excellent quality with respect to APC; problems observed were at the retail level. Listeria spp. and L. monocytogenes were isolated from 16.7% and 6.7% of the samples, respectively. Vibrio spp. were present in 63.3% of the samples, more often isolated from shrimp from Mexico or China than Ecuador. The majority of isolates were identified as V. parahaemolyticus (36.7%), V. alginolyticus (26.7%), or V. vulnificus (16.7%), and 53.7% were resistent to at least one antibiotic. These data reveal frozen, raw shrimp imported from Ecuador was superior quality.

Clostridium perfringens may be the most widely occurring bacterial pathogen and is responsible for a variety of diseases in both humans and animals. The virulence of this organism is associated with the ability to produce an estimated 17 potential exotoxins. The production of one or more of the five major toxins (α,β,ε, and ι) is the basis for placing isolates into five toxigenic types, A through E. Enterotoxin (CPE), is not used in typing but is considered a major virulence factor. A multiplex PCR genotyping assay was developed, utilizing primers derived from sequences of cpa, cpb, etx, iA, and cpe, yielding products of 324, 196, 655, 446, and 233 bp, respectively. Template for this assay was derived from individual colonies suspended in 200 μl of HPLC-grade water, boiled for 20 min or heated in a microwave oven for 10 min at 700 W. Included in the 50 μl reaction volume was 10 μl of template, 0.15 to 0.7 μM of each primer, 0.1 mM dNTPs, 2 mM MgCl₂, and 2 units of Taq DNA polymerase. The PCR products were examined by electrophoresis in a 1.5% agarose gel stained with EtBr. Correlation of genotype with toxin phenotype in strains examined by mouse inoculation was excellent, and it was possible to provide results rapidly, usually in < 4 h. An ELISA procedure was established for detection of β toxin produced by C. perfringens types B and C. The ELISA was used to differentiate Cpb⁺ from Cpb⁻ isolates grown in overnight broth cultures and to measure β toxin in commercial fermentations of type C organisms. In addition to the above assays, preliminary work was initiated on the development of a PCR procedure for quantitation of C. perfringens in clinical or environmental samples, and involved the construction of a 233 bp homologous, competitive mimic from a restriction digest of a 323 bp PCR product generated from cpa.

Recently, a new strain of B. subtilis (Bull913) carrying Tn917, a Streptococcus-derived transposon that confers erythromycin and lincomycin resistance, in the host chromosome has been isolated that grows as multistrand helical structures. Bull913 can produce macrofibers whose properties are like another B. subtilis strain FJ7. FJ7 is a lyt-2 mutant produced by chemical mutagenesis which can form macrofibers with twists ranging from right to left handed. Bull913 also has this spectrum of twisted states. Bull913 macrofibers are similar to FJ7 but are longer lived than FJ7. The Macrofiber properties of Bull913 were compared to FJ7 using growth in liquid media supplemented with (NH₄)₂SO₄ or MgSO₄ -- conditions giving LH or RH macrofibers, respectively for FJ7. The autolysin activities and cell walls substrate properties of Bull913 were biochemically analyzed and compared to those of strains 168 and FJ7. Polyacrylamide gel electrophoresis (PAGE) was used to compare the wall proteins from all three strains. Finally, genetic studies of Bull913 were carried out to determine if the defect in Bull913 is in the lyt-1, lyt-2 or lyt-15 genes, or in a new gene. Both biochemical analysis and genetic studies suggest that Bul1913 carries Tn917 in the lyt-2 gene.

Electrolytically generated copper and silver ions (400:40 and 800:80 μg/L) with and without chlorine (1 mg/L) were evaluated for their efficacy in reducing numbers of viable Naegleria fowleri amoebas in well water (23-25°C and pH 7.3). A 99.9% reduction was achieved by 10 minutes exposure to 1 mg/L free chlorine compared to 8 minutes with chlorine combined with copper:silver (800:80 μg/L). Copper:silver alone showed minimal reduction of N. fowleri after 72 hours exposure. Addition of 1 mg/L free chlorine to copper:silver at concentrations of 400:40 or 800:80 μg/L resulted in significantly enhanced inactivation rates (k = 0.4575 and 0.515 log₁₀ reduction/minute, respectively) than with chlorine alone (k = 0.33). Enhanced inactivation of N. fowleri with combined copper:silver and chlorine may be a consequence of multiple sites of attack on the amoeba membrane by the different disinfectants.

The deamination of 5-methyl cytosine produces a mismatched base pair which of itself can not be distinguished from a mismatch arising from a different original base pair. We investigated whether the methylation remaining of the opposite strand in the symmetrical CpG dinucleotide might provide a signal for template choice in SV40. There is evidence that methylation may be a signal in procaryotes. / SV40 mismatched at the single Hpa II site (CCGG) was used to transfect CV-1 cells. The sequence at the Hpa II site in the resulting progeny was probed by restriction analysis. Methylation at the Hpa II site on the WT parental strand of the mismatch increased the frequency with which WT was observed in the progeny. This is interpreted as reflecting a preference for the methylated strand to be used as a template in mismatch repair. Methylation at the Hha I site, GCGC, 3 bases away from the mismatch did not increase the proportion of WT clones recovered when the methylation was present on the WT strand. However, when the WT strand of the mismatch was methylated by a bacterial host at the Eco RII, CC('A)GG, and the Mbo I, GATC, sites an increased preference for WT as template was observed. This effect was additive with the effect of Hpa II methylation. These effects were approximately equal even though Hpa II methylation involves only one site while Eco RII methylation and Mbo I methylation are present at 16 and 8 sites respectively. / Having a much stronger influence on strand choice than any methylation pattern was the position of nicks in the mismatch. When the heteroduplex was nicked at the unique Bam HI and Eco RI sites, 2187 bp and 1436 bp away from the mismatch respectively, the strand with the nick closest to the mismatch was preferentially used as the template. We demonstrate that this would not be expected if an enzyme recognizing the nick could move in only one direction. We suggest that this mismatch repair system may operate at the replication fork recognizing the transiently unmethylated nascent strand. / Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0064. / Thesis (Ph.D.)--The Florida State University, 1984.

Lipid analysis was used to clarify the taxonomy of sulfate-reducing bacteria (SRB) to determine the composition of sulfate-reducing sedimentary communities. The phospholipid fatty acid composition of Desulfovibrio desulfuricans, Desulfotomaculum orientis, Desulfotomaculum nigrificans, and four SRB isolated from salt marsh sediment were determined by capillary gas-liquid chromatography and mass fragmentography. The fatty acid compositions of the SRB were compared using multivariate statistics and contrasted to the fatty acid compositions of Bacillus subtilus, Clostridium butyricum, Esherichia coli, Pseudomonas putida, Moraxella, sp. and Athrobacter sp. All SRB examined contained predominantly iso and anteiso methyl branched acids. Desulfovibrio desulfuricans, Desulfotomaculum orientis and Desulfotomaculum nigrificans contained high proportions of an uncommon 17 carbon iso monounsaturated acid. The major differences in fatty acid compositions among SRB were quantitative while the major differences between SRB and the other bacteria examined were qualitative. The fatty acid composition of Bacillus subtilus was most similar to those of the SRB in that it contained high proportions of branched saturated and monounsaturated acids. Esherichia coli and Clostridium butyricum were characterized by high proportions of 16 and 18 carbon saturated straight chained acids and 17 and 19 carbon cyclopropane acids. Pseudomonas putida and Moraxella sp. contained high proportions of 16 and 18 carbon monounsaturated acids. The fatty acid composition of Arthrobacter sp. was quite simple in that 90% of the acids was an iso methyl branched 15 carbon acid. / The phospholipid fatty acid composition of the microbial communities of freshwater and estuarine sediments were determined by analogous methods. The freshwater sediments were characterized by phospholipid concentrations which were 100 times higher than estuarine sediments and by high proportions of straight-chained saturated acids. The estuarine sediments contained higher proportions of branched and monounsaturated acids. The lipid content of all sediments generally decreased with depth and iso and anteiso branched acids became more abundant. Estuarine sediments taken from three locations along a 10 meter transect through a salt marsh were shown to vary 10 fold in lipid content and by a factor of 1000 in rates of sulfate respirations. Differences in microbial communities were demonstrated by their phospholipid fatty acid compositions and by their metabolism of carbon-14 labeled substrates. / Source: Dissertation Abstracts International, Volume: 45-09, Section: B, page: 2817. / Thesis (Ph.D.)--The Florida State University, 1984.

A three-part study of the involvement of detrital microbiota in an estuarine trophic system was conducted: (1) the evidence for microbial succession on allochthonous plant litter in Apalachicola Bay, Florida; (2) the effects of grazing by gammaridean amphipods on the detrital microbiota; and (3) the use of the detrital microbiota as a food source by estuarine gammaridean amphipods. / Changes in hydrolytic, respiratory, catabolic and lipid biosynthetic activities depended at least in part on successional changes in the microbial communities on allochthonous plant litter incubated in a semi-tropical estuary. Initial colonization was by populations which had a high content of muramic acid relative to the adenosine triphosphate (ATP) and which were progressively displaced by a microbiota with a lower ratio of muramic acid to ATP. Scanning electron microscopy (SEM) of the plant-litter microbiota showed a succession of forms, with an initial bacterial colonization and its progressive displacement by more complex forms. Estimates of the microbial mass and the rates of phospholipid synthesis suggested that the detrital microbiota have a relatively slow growth rate compared to the growth potential. / The effects of grazing by estuarine gammaridean amphipods on the detrital microbiota were studied. Amphipods grazing at natural population density on detrital microbiota affected the microbial community composition, biomass and metabolic activity, without affecting the physical structure of the leaves. Total microbial biomass estimated by ATP and lipid phosphate or observed by SEM was greater on grazed than on ungrazed detritus. The rates of oxygen consumption, poly-(beta)-hydroxybutyrate (PHB) synthesis, total lipid biosynthesis and release of ('14)CO(,2) from radioactively prelabeled microbiota were higher on grazed leaves than on ungrazed, indicating a stimulation of the metabolic activity of grazed detrital microbes. This was true with rates based either on the dry leaf weight or microbial biomass. Alkaline phosphatase activity was lower in the grazed system, consistent with enhanced inorganic phosphate cycling. The loss of ('14)C from both total lipid and PHB of microorganisms prelabeled with ('14)C was greater from grazed than ungrazed microbes. There was a faster decrease in the ('14)C-glycolipid than in the ('14)C-neutral lipid or ('14)C-phospholipid fraction. Analysis of specific phospholipids showed losses of the metabolically stable ('14)C-glycerolphosphoryl choline. derived from phosphatidyl choline and much more rapid metabolism of the bacterial lipid phosphatidylglycerol measured as ('14)C-glycerol phosphoryl glycerol with amphipod grazing. The biochemical data supported SEM observations of a shift, as the grazing proceeded, from a bacterial/fungal community to one dominated by bacteria. / Three lines of evidence indicated that gammaridean amphipods grazed the microbiota that colonizes estuarine allochthonous detritus. Dried, biologically inactive oak leaves (Quercus virginiana Mill) became covered by microorganisms during incubation in the estuary. Grazing by amphipods, at a density of 3.3 amphipods/cm('2) leaf, decreased the microbial biomass, as measured by the extractible ATP, on the leaf. In SEM examinations of grazed detritus, the leaf surfaces appeared substantially cleared of microbes by the amphipods. Incubation of detritus with ('14)C-labeled precursors showed that the isotope was incorporated by the leaf microbiota. Grazing by amphipods on detritus with ('14)C-labeled microorganisms resulted in a decrease in the ('14)C associated with the leaves, accompanied by a significant increase in the amount of ('14)C recovered in the amphipods. One-third of the ('14)C recovered in the amphipods, whose guts had been cleared of ('14)C-labeled detritus, was recovered in the lipid fraction of the amphipods, indicating assimilation of the detrital microorganisms by the amphipods. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0826. / Thesis (Ph.D.)--The Florida State University, 1980.

Source: Dissertation Abstracts International, Volume: 32-11, Section: B, page: 6541. / Thesis (Ph.D.)--The Florida State University, 1971.

I have designed an improved method of matric water potential regulation in which relative humidity is controlled by the temperature difference between a saturated atmosphere and a connected experimental chamber. Versatility, ease of operation, and lack of interference with the gaseous composition of the experimental atmosphere are the major advantages of this system over other methods such as salt solutions. / The water potential control system was used to investigate the role of thallus structure in CO$\sb2$ uptake of two hot desert lichen species under water stress. Photosynthesis of isolated lichen phycobiont cells at low water potentials was also examined. Within the lichen thallus, matric water potentials higher than ambient appear to result from physical properties of the fungal matrix. Increased water availability supports photosynthesis by the enclosed phycobiont at low ambient phycobiont (Trebouxia sp.) photosynthesize well under water stress. The combination of increased internal water availability and desiccation-tolerant phycobiont cells results in the survival of these lichens in an extremely arid climate. The two species occupy different microhabitats as a consequence of differences in CO$\sb2$ uptake under saturating conditions and hydrophobicity. / The role of the endolithic habitat (enclosure) in the water economy of the cryptoendolithic microbial communities from the Ross Desert (Antarctica) and the Negev Desert (Israel) was examined. Colonized sandstone rocks adsorb or condense water vapor in pore spaces. This water supports photosynthesis by the Ross Desert cryptoendolithic lichen community but does not create conditions suitable for photosynthesis of Negev Desert cryptoendolithic cyanobacteria. The difference between the two communities is that cyanobacteria are similar to other prokaryotes: water potentials approaching that of liquid water are necessary for bacterial metabolism whereas eukaryotes typically function under water stress. / Source: Dissertation Abstracts International, Volume: 49-03, Section: B, page: 0635. / Major Professor: E. Imre Friedmann. / Thesis (Ph.D.)--The Florida State University, 1987.