bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence of
Nosema locustae
Spores in Soil as Determined by Fluorescence Microscopy
Authors: Germida James J.
Published: January 2020

Nosema locustae
, a protozoan parasite of grasshoppers, is used as a bioinsecticide. In the present study, the persistence of
N. locustae
spores in soil and the interaction of these spores with the indigenous soil microflora were examined with various forms of microscopy and staining. Fluorescence microscopy was found to be better than phase-contrast or bright-field microscopy for detecting and viewing spores in soil. Fluorescein isothiocyanate was a better fluorescent stain than acridine orange or fluorescein diacetate; water-soluble aniline blue did not stain spores. The eight bright-field microscopy stains tested (phenolic erythrosin, phenolic rose bengal, malachite green, crystal violet, safranin, Congo red, methyl red, and eosin B) were not satisfactory, as spore staining characteristics were either poor or masked by overstained soil debris. A procedure was developed which allowed spores to be extracted from soil with a peptone-phosphate buffer, recovered on a membrane filter, and stained with fluorescein isothiocyanate for microscopic counting. This procedure was used to assess the persistence of
N. locustae
spores in field and laboratory soils. The number of
N. locustae
spores in a laboratory model soil system persisted at a high level for over 8 weeks when the soil was incubated at 5°C but exhibited a 1,000-fold decrease after 1 week of incubation at 27°C. Persistence was related to the temperature-dependent activity of the indigenous soil microflora, which, on the basis of microscopic observations, appeared to prey on
N. locustae
spores.
N. locustae
spores were detected in an
N. locustae
-treated field soil at a low level consistent with the level for laboratory soil incubated at 27°C, and they persisted at this level for over 2 months. No spores were detected on vegetation from this field or in the soil from an adjacent, nontreated control field.
N. locustae
-like spores were also detected in soil from nontreated fields supporting large grasshopper populations.
Protoplast Fusion of
Trichoderma reesei
, Using Immature Conidia
Authors: Toyama Hideo , Yamaguchi Kohtaro , Shinmyo Atsuhiko , Okada Hirosuke
Published: January 2020

Protoplast fusion of strains derived from
Trichoderma reesei
QM9414 and QM9136 and the segregation of the resulting fusants were studied. Combinations of protoplasts prepared from young conidia with double amino acid requirements, one of which was a common requirement and the other uncommon, were fused in the presence of polyethylene glycol 6000. Fusants were selected as regenerant colonies requiring only the commonly deficient amino acid. The frequency of fusion was 0.9 × 10
−4
to 4.0 × 10
−4
for the starting conidia and 3.0 × 10
−2
to 4.9 × 10
−2
for the regenerated protoplasts, which was significantly higher than the expected reversion frequencies by mutation. Conidia generated on the fusant colonies showed diverse phenotypes, i.e., parental types (40 to 80%) and nonparental types (20 to 60%). Colonies developed from single conidia of the nonparental phenotype contained special spots called “knobs” that have a higher density of mycelia. The phenotype of the knobs was again varied among prototrophs, parental types, and recombinant types; and their traits were inherited stably. The phenotype of the mycelia in the nonknob part was essentially the same as that of the original conidia and again formed knobs in colonies upon transfer of a piece of mycelia to a fresh medium. The conidial DNA content of the knob clone was almost the same as that of the parents, but that of the fusants was 1.2 to 2.0 times higher than that of the parents. From these results, we conclude that knobs are the segregants from the fusants. One knob clone showed twice the carboxymethyl cellulose hydrolyzing activity of the parents, suggesting the possibility of breeding
T. reesei
cells by the protoplast fusion technique.
Preparation, Characterization, and Microbial Degradation of Specifically Radiolabeled [
14
C]Lignocelluloses from Marine and Freshwater Macrophytes
Authors: Benner Ronald , Maccubbin A. E. , Hodson Robert E.
Published: January 2020

Specifically radiolabeled [
14
C-lignin]lignocelluloses were prepared from the aquatic macrophytes
Spartina alterniflora, Juncus roemerianus, Rhizophora mangle
, and
Carex walteriana
by using [
14
C]phenylalanine, [
14
C]tyrosine, and [
14
C]cinnamic acid as precursors. Specifically radiolabeled [
14
C-polysaccharide]lignocelluloses were prepared by using [
14
C]glucose as precursor. The rates of microbial degradation varied among [
14
C-lignin]lignocelluloses labeled with different lignin precursors within the same plant species. To determine the causes of these differential rates, [
14
C-lignin]lignocelluloses were thoroughly characterized for the distribution of radioactivity in nonlignin contaminants and within the lignin macromolecule. In herbaceous plants, significant amounts (8 to 24%) of radioactivity from [
14
C]phenylalanine and [
14
C]tyrosine were found associated with protein, although very little (3%) radioactivity from [
14
C]cinnamic acid was associated with protein. Microbial degradation of radiolabeled protein resulted in overestimation of lignin degradation rates in lignocelluloses derived from herbaceous aquatic plants. Other differences in degradation rates among [
14
C-lignin]lignocelluloses from the same plant species were attributable to differences in the amount of label being associated with ester-linked subunits of peripheral lignin. After acid hydrolysis of [
14
C-polysaccharide]lignocelluloses, radioactivity was detected in several sugars, although most of the radioactivity was distributed between glucose and xylose. After 576 h of incubation with salt marsh sediments, 38% of the polysaccharide component and between 6 and 16% of the lignin component (depending on the precursor) of
J. roemerianus
lignocellulose was mineralized to
14
CO
2
; during the same incubation period, 30% of the polysaccharide component and between 12 and 18% of the lignin component of
S. alterniflora
lignocellulose was mineralized.
Kinetics of Sulfate and Acetate Uptake by
Desulfobacter postgatei
Authors: Ingvorsen Kjeld , Zehnder Alexander J. B. , Jørgensen Bo B.
Published: January 2020

The kinetics of sulfate and acetate uptake was studied in the sulfate-reducing bacterium
Desulfobacter postgatei
(DSM 2034). Kinetic parameters (

K
m

and
V
max
) were estimated from substrate consumption curves by resting cell suspensions with [
35
S]sulfate and [
14
C]acetate. Both sulfate and acetate consumption followed Michaelis-Menten saturation kinetics. The half-saturation constant (

K
m

) for acetate uptake was 70 μM with cells from either long-term sulfate- or long-term acetate-limited chemostat cultures. The average

K
m

value for sulfate uptake by
D. postgatei
was about 200 μM.

K
m

values for sulfate uptake did not differ significantly when determined with cells derived either from batch cultures or sulfate- or acetate-limited chemostat cultures. Acetate consumption was observed at acetate concentrations of ≤1 μM, whereas sulfate uptake usually ceased at 5 to 20 μM. The results show that
D. postgatei
is not freely permeable to sulfate ions and further indicate that sulfate uptake is an energy-requiring process.
Mutation and Selection of
Lactobacillus plantarum
Strains That Do Not Produce Carbon Dioxide from Malate
Authors: Daeschel M. A. , McFeeters R. F. , Fleming H. P. , Klaenhammer T. R. , Sanozky R. B.
Published: January 2020

A differential medium was developed to distinguish between malate-decarboxylating (MDC
+
) and -non-decarboxylating (MDC
−
) strains of
Lactobacillus plantarum.
MDC
−
strains produced a visible acid reaction in the medium, whereas MDC
+
strains did not. Use of the medium allowed for rapid screening and isolation of mutagenized cells that had lost the ability to produce CO
2
from malate.
Baleen whales: preliminary evidence for forestomach microbial fermentation
Authors: Herwig R P , Staley J T , Nerini M K , Braham H W
Published: January 2020

Baleen whales have a multichambered stomach divided into three distinct compartments. The forestomach (first compartment) consists of noncornified and nonglandular tissue and appears to be analogous to the tissue of the rumen. The exact function of the forestomach is unknown; however, we have detected volatile fatty acids in forestomach samples from seven bowhead (Balaena mysticetus) and four gray (Escherichtius robustus) whales. Acetic, propionic, and butyric acids were found in all samples. Seven whale samples also contained valeric, isobutyric, isovaleric, and isocaproic acids. Bacterial counts in 10 of the samples ranged from 5 X 10(8) to 630 X 10(8)/ml of fluid. The types, concentrations, and relative proportions of volatile fatty acids, the presence of significant levels of bacteria, and the morphology of the digestive tract support the hypothesis that a microbial forestomach fermentation occurs in these two species of baleen whales.
Application of the Indirect Immunoperoxidase Stain Technique to the Flagella of
Azospirillum brasilense
Authors: Hall Patrick G. , Krieg Noel R.
Published: January 2020

An indirect immunoperoxidase stain was used to demonstrate by electron microscopy that an antigenic difference exists between the polar flagellum and the lateral flagella of
Azospirillum brasilense
ATCC 29145.
Procedure for increased recovery of Campylobacter jejuni from inoculated unpasteurized milk
Authors: Koidis P , Doyle M P
Published: January 2020

Different treatments were applied to Campylobacter jejuni-inoculated unpasteurized milk to identify means of enhancing the survival of the organism in refrigerated (4 degrees C) samples. The greatest survival occurred in milk supplemented with 0.01% sodium bisulfite and held under an atmosphere of 100% nitrogen (bisulfite-nitrogen), in most instances allowing isolation of C. jejuni from highly contaminated milk 15 or more days longer than from unsupplemented milk held in air (21% oxygen). Although a larger amount of Campylobacter was consistently recovered from milk treated with bisulfite-nitrogen, similar isolation rates (qualitative) resulted from milk stored in air and supplemented with 0.01% sodium bisulfite and 0.15% sodium thioglycolate when analyzed within 12 days after sampling. Milk samples to be transported and assayed at a later date would best be held refrigerated (4 degrees C) and supplemented with 0.01% sodium bisulfite and either 0.15% sodium thioglycolate or an atmosphere of 100% nitrogen.
Correlation of Aflatoxin Contamination With Zinc Content of Chicken Feed
Authors: Jones Frank T. , Hagler Winston M. , Hamilton Pat B.
Published: January 2020

Feed samples from chicken houses in five commercial chicken operations were analyzed for Zn, Mn, Fe, Cu, Cd, and aflatoxin content. Mean aflatoxin content of these samples was 14 ppb (14 ng/g) as opposed to 1.2 ppb in samples taken when the feed was made. Aflatoxin content of the feed samples correlated (
r
= 0.325) significantly (
P
< 0.05) with Zn content but not with Mn, Fe, or Cu, all of which correlated significantly with Zn. Zn content of unamended feed (<20 ppm [20 μg/g]) is normally supplemented with a mineral premix containing Zn, Mn, Fe, and Cu to meet the nutrient requirements of chickens (40 ppm of Zn). The mean zinc concentration of the feed samples (117 ppm) was about threefold greater than the nutrient requirement and ranged from 58 to 162 ppm in individual samples. These field survey results parallel earlier reports of augmented production of aflatoxin in monocultures of aflatoxigenic fungi in corn and other ingredients supplemented with Zn. These results suggest that stricter control of Zn levels during manufacture could reduce aflatoxin contamination of feed consumed by chickens.
Averufin, an anthraquinone mycotoxin possessing a potent uncoupling effect on mitochondrial respiration
Authors: Kawai K , Nozawa Y , Maebayashi Y , Yamazaki M , Hamasaki T
Published: January 2020

Averufin and averufin dimethylether from Aspergillus versicolor were examined for their uncoupling effects on oxidative phosphorylation in isolated rat liver mitochondria to get insight into the mode of toxic action of averufin. Averufin uncoupled oxidative phosphorylation, causing 50% uncoupling at about 1.5 microM with respect to the decrease in P/O ratio. Averufin dimethylether did not uncouple but inhibited state 3 respiration of mitochondria, which was not released by either 2,4-dinitrophenol or averufin.
Suicide Inactivation of Catechol 2,3-Dioxygenase from
Pseudomonas putida
mt-2 by 3-Halocatechols
Authors: Bartels Iris , Knackmuss Hans-Joachim , Reineke Walter
Published: January 2020

The inactivation of catechol 2,3-dioxygenase from
Pseudomonas putida
mt-2 by 3-chloro- and 3-fluorocatechol and the iron-chelating agent Tiron (catechol-3,5-disulfonate) was studied. Whereas inactivation by Tiron is an oxygen-independent and mostly reversible process, inactivation by the 3-halocatechols was only observed in the presence of oxygen and was largely irreversible. The rate constants for inactivation (

K
2

) were 1.62 × 10
−3
sec
−1
for 3-chlorocatechol and 2.38 × 10
−3
sec
−1
for 3-fluorocatechol. The inhibitor constants (

K
i

) were 23 μM for 3-chlorocatechol and 17 μM for 3-fluorocatechol. The kinetic data for 3-fluorocatechol could only be obtained in the presence of 2-mercaptoethanol. Besides inactivated enzyme, some 2-hydroxyhexa-2,4-diendioic acid was formed from 3-chlorocatechol, suggesting 5-chloroformyl-2-hydroxypenta-2,4-dienoic acid as the actual suicide product of
meta
-cleavage. A side product of 3-fluorocatechol cleavage is a yellow compound with the spectral characteristics of a 2-hydroxy-6-oxohexa-2,4-dienoic acid indicating 1,6-cleavage. Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation.
Production of a novel dimeric metabolite of primaquine by Streptomyces rimosus
Authors: Clark A M , Hufford C D , Puri R K , McChesney J D
Published: January 2020

Primaquine, an 8-amino-6-methoxyquinoline antimalarial agent, was subjected to metabolic studies with microorganisms. Streptomyces rimosus converted primaquine to the previously reported N-acetyl derivative. Continued incubation of S. rimosus resulted in the formation of a minor dimeric metabolite. The structure of the minor dimeric metabolite was proposed based primarily on its spectral data (1H and 13C nuclear magnetic resonance spectra and mass spectrum). The proposed structure of the metabolite was confirmed by synthesis of the dimer by treatment of primaquine-N-acetate with potassium ferricyanide in a biphasic chloroform-aqueous sodium bicarbonate system with a phase-transfer catalyst. Since (+/-)-primaquine was used for both the microbial transformation and synthesis, a diastereomeric mixture of symmetrical dimers was formed in each case. The metabolite sample was identical to the synthetic sample, as shown by direct comparison (thin-layer chromatography, co-thin-layer chromatography, high-pressure liquid chromatography, co-high-pressure liquid chromatography, 1H nuclear magnetic resonance spectra, and mass spectrum).
Interaction of
Escherichia coli
B and B/4 and Bacteriophage T4D with Berea Sandstone Rock in Relation to Enhanced Oil Recovery
Authors: Chang Philip L. , Yen Teh Fu
Published: January 2020

Much research and development is needed to recover oil reserves presently unattainable, and microbially enhanced oil recovery is a technology that may be used for this purpose. To address the problem of bacterial contamination in an oil field injection well region, we connected each end of a Teflon-sleeved Berea sandstone rock to a flask containing nutrient medium. By inoculating one flask with
Escherichia coli
B, we could observe bacterial growth in the uninoculated flask resulting from the transport and establishment of cells across the rock. Differences in bacterial populations occurred depending on whether bacteriophage T4D was first adsorbed to the rock. The results of these experiments indicate that the inhibition of bacterial establishment within a rock matrix is possible via lytic interaction. Some nonlytic effects are also implied by experiments with B/4 cells, which are T4D-resistant mutants of
E. coli
B. A 10 to 40% retention of T4 by the rock occurred when it was loaded with 10
5
to 10
6
PFU. We also describe a lysogenic system for possible use in microbially enhanced oil recovery techniques.
Negative correlation between protozoal and bacterial levels in rumen samples and its relation to the determination of dietary effects on the rumen microbial population
Authors: Teather R M , Mahadevan S , Erfle J D , Sauer F D
Published: January 2020

The bacterial protein content and protozoal protein content of unfractionated samples from the liquid-small particle phase of the rumen were determined on the basis of direct microscopic measurement of bacteria numbers and protozoa numbers and cell volumes. Standard values of 8.7 X 10(-11) mg of protein per bacterial cell and 5.9 X 10(-11) mg/micron 3 of protozoa cell volume, obtained from analysis of isolated cells, were used to convert the microscopic measurements to an estimate of the protein content of the rumen sample. When the correlation between bacterial and protozoal protein levels was examined within groups of animals, a highly significant negative correlation between these two parameters was found (P less than 0.001). The variation among animals for total (bacterial plus protozoal) microbial protein was smaller than the variation among animals for bacterial or protozoal protein alone. There was also a highly significant positive correlation (P less than 0.001) between protozoal protein level and total microbial protein level. The variation found among animals in total microbial protein level could be reduced by using a regression equation determined for bacterial versus protozoal protein to correct for the different population dynamics of the two groups.
Degradation of the γ-Carboxyl-Containing Diarylpropane Lignin Model Compound 3-(4′-Ethoxy-3′-Methoxyphenyl)-2-(4″-Methoxyphenyl)Propionic Acid by the Basidiomycete
Phanerochaete chrysosporium
Authors: Gold Michael H. , Enoki Akio , Morgan Meredith A. , Mayfield Mary B. , Tanaka Hiromi
Published: January 2020

The white-rot basidiomycete
Phanerochaete chrysosporium
metabolized 3-(4′-ethoxy-3′-methoxyphenyl)-2-(4″-methoxyphenyl)propionic acid (V) in low-nitrogen, stationary cultures, conditions under which ligninolytic activity is expressed. The ability of several fungal mutant strains to degrade V reflected their ability to degrade [
14
C]lignin to
14
CO
2
. 1-(4′-Ethoxy-3′-methoxyphenyl)-2-(4″-methoxyphenyl)-2- hydroxyethane (VII), anisyl alcohol, and 4-ethoxy-3-methoxybenzyl alcohol were isolated as metabolic products, indicating an initial oxidative decarboxylation of V, followed by α, β cleavage of the intermediate (VII). Exogenously added VII was rapidly converted to anisyl alcohol and 4-ethoxy-3-methoxybenzyl alcohol. When the degradation of V was carried out under
18
O
2
,
18
O was incorporated into the β position of the diarylethane product (VII), indicating that the reaction is oxygenative.
Colonization of congenitally athymic, gnotobiotic mice by Candida albicans
Authors: Balish E , Balish M J , Salkowski C A , Lee K W , Bartizal K F
Published: January 2020

Colony counts, scanning electron microscopy, and light microscopy were used to assess the capacity of Candida albicans to colonize (naturally) and infect the alimentary tract of adult and neonatal (athymic [nu/nu] or heterozygous [+/nu] littermates) germfree BALB/c mice. When exposed to yeast-phase C. albicans, the alimentary tract of adult germfree mice (nu/nu or +/nu) is quickly (within 24 to 48 h) colonized with yeast cells. Neither morbidity nor mortality was evident in any mice that were colonized with a pure culture of C. albicans for 6 months. Yeast cells of C. albicans predominated on mucosal surfaces in the oral cavities and vaginas of adult athymic and heterozygous mice. In both genotypes, C. albicans hyphae were observed in keratinized tissue on the dorsal posterior tongue surface and in the cardial-atrium section of the stomach. Conversely, neonatal athymic or heterozygous mice, born to germfree or C. albicans-colonized mothers, do not become heavily colonized or infected with C. albicans until 11 to 15 days after birth. Although yeast cells adhered to some mucosal surfaces in vivo, neither widespread mucocutaneous candidiasis, i.e., invasion of mucosal surfaces with C. albicans hyphae, nor overwhelming systemic candidiasis was evident in neonatal (nu/nu or +/nu) mice. Thus, even in the absence of functional T-cells and a viable bacterial flora, athymic and heterozygous littermate mice (adult or neonatal BALB/c) that are colonized with a pure culture of C. albicans manifest resistance to extensive mucocutaneous and systemic candidiasis.
Eradication of Salmonella and Arizona species from turtle hatchlings produced from eggs treated on commercial turtle farms
Authors: Siebeling R J , Caruso D , Neuman S
Published: January 2020

On commercial turtle farms more than 40% of the hatchlings excrete detectable levels of Salmonella and Arizona spp. when hatched from nonsanitized eggs incubated in sawdust or dirt-filled chambers. Over a 3-year period on 10 farms, more than 10(6) turtle eggs were treated in an attempt to hatch Salmonella-free turtles. Eggs were sanitized in disinfectant, treated by temperature- or pressure-differential dip methods in solutions containing 500 micrograms or more of gentamicin sulfate per ml, and hatched in sanitized plastic chambers free of bedding material. The Salmonella and Arizona spp. infection levels for turtles produced from treated eggs were 0 and 1.12% for years 1 and 2, respectively, whereas infection levels for hatchlings produced from nontreated eggs during these periods were 47 and 44%, respectively. During year 3, dip solutions were filtered daily, treated at 100 degrees C for 15 min on a weekly basis to free the solution of microbial contaminants and egg protein, charged with gentamicin after 10,000 to 20,000 eggs had been treated to maintain antimicrobial activity at 500 micrograms/ml or more, and maintained at pH 6.0 to preserve optimal antimicrobial activity. The implementation of these measures in year 3 resulted in an infection level of 0.15% when the tissues of 3 of 1,959 hatchlings tested were positive for Salmonella and Arizona spp., whereas the tissues of 66 (49.0%) of 135 hatchlings produced from nontreated eggs were positive.
Influence of the membrane on T-2 toxin toxicity in Saccharomyces spp
Authors: Schappert K T , Khachatourians G G
Published: January 2020

In growing cells of Saccharomyces cerevisiae and Saccharomyces carlsbergensis, T-2 toxin inhibits cell growth. We have examined the role of the yeast membranes in the uptake mechanism(s) of T-2 toxin. The effects of membrane-modulating agents, ethanol, cetyltrimethylammonium bromide, Triton X-100, and heat were studied; these agents were found to increase the sensitivity of the yeasts toward T-2 toxin. In the presence of 5% (vol/vol) ethanol, 2 micrograms of T-2 toxin per ml caused complete inhibition of growth. In the presence of 1 microgram of cetyltrimethylammonium bromide per ml, yeast cells became sensitive to T-2 toxin, starting with a concentration of 0.5 micrograms/ml. Triton X-100 at concentrations below 1% (vol/vol) sensitized the cells toward T-2 toxin, but at higher concentrations it protected the cells from T-2 toxin. Temperatures of incubation between 7 and 30 degrees C influenced the growth reduction caused by T-2 toxin. The greatest observed reduction of growth in T-2 toxin-treated cultures occurred at 30 degrees C. To further prove that the membrane influences the interaction of T-2 toxin with yeasts, we have studied a yeast mutant with a reduced plasma membrane permeability (G. H. Rank et al., Mol. Gen. Genet. 152:13-18, 1977). This yeast mutant proved to be resistant to T-2 toxin concentrations of up to 50 micrograms/ml. These results show that the membrane plays a significant role in the interaction of T-2 toxin with yeast cells.
Production of two phosphatases by Lysobacter enzymogenes and purification and characterization of the extracellular enzyme
Authors: von Tigerstrom R G
Published: January 2020

Lysobacter enzymogenes produces an extracellular phosphatase (EC. 3.1.3.1) during the stationary phase of growth. The cells also produce a cell-associated alkaline phosphatase. This enzyme is found in the particulate fraction of cell extracts and may be membrane bound. The production of both phosphatases, especially the extracellular enzyme, is reduced by inorganic phosphate. The extracellular phosphatase was purified to a specific activity of 270 U/mg primarily by chromatography on carboxymethyl cellulose and gel filtration. The enzyme is stable under normal storage conditions but is rapidly inactivated above 70 degrees. It consists of one polypeptide with an approximate molecular weight of 25,000. The pH optimum is 7.5, and the Km for p-nitrophenylphosphate is 2.2 X 10(-4) M. The enzyme degrades a number of other phosphomonoesters but at a reduced rate compared with the rate obtained with p-nitrophenylphosphate. Phosphate and arsenate inhibit the enzyme, but EDTA and other chelating agents have no effect. The lack of a metal ion requirement for activity, the lower molecular weight, the soluble nature of the enzyme, and the lower pH optimum clearly distinguish the extracellular phosphatase from the cell-associated phosphatase and from other bacterial phosphatases.
Properties of Alginate Lyases from Marine Bacteria
Authors: Doubet R. Scott , Quatrano Ralph S.
Published: January 2020

Alginate lyases (EC 4.2.2.3) from two marine bacteria were isolated and partially characterized. A cell-bound lyase from isolate A3 had a molecular weight of approximately 100,000 and cleaved mannuronate blocks, apparently in an exo manner. A lyase recovered from the culture medium of isolate W3 was soluble in saturated ammonium sulfate, cleaved guluronate blocks, apparently in an endo manner, and had a molecular weight of 35,000. The thiobarbiturate test and urea-polyacrylamide gel electrophoresis were used to determine substrate specificity and mode of substrate cleavage by the enzymes.
Successive changes in the epimural bacterial community of young lambs as revealed by scanning electron microscopy
Authors: Mueller R E , Asplund J M , Iannotti E L
Published: January 2020

Scanning electron microscopy was used to determine the time of initial colonization of the rumen epithelium of young lambs and successive changes with time in the morphological composition of the epimural community. Tissue samples were obtained from two groups of lambs at 1, 2, 4, 6, 8, and 10 weeks of age. Comparisons were made with the epimural communities observed at 12 well-distributed sites in the rumen of a mature wether. Epimural bacteria were already present on the epithelium at 1 week of age. The morphological composition of the epimural community changed with age, with the pattern of succession being similar in both groups of lambs. A total of 24 morphotypes were distinguished by scanning electron microscopy; 17 were rod shaped, 4 were cocci, 2 were spiral, and 1 was filamentous. These morphotypes were further subdivided into: (i) those persisting after their initial colonization in young lambs and present in the adult (7 morphotypes), (ii) those seen only in the adult (2 morphotypes), and (iii) those present only in young lambs (15 morphotypes). The seven morphotypes present in both the lamb and the adult could be considered indigenous members of the epimural community. Several morphotypes appeared restricted in their colonization to certain regions of the papillae, suggesting the presence of microhabitats within the epithelial habitat. Two rod-shaped bacteria were repeatedly seen specifically attached to one another, suggesting an interspecific association.
Isolation and identification of adherent epimural bacteria during succession in young lambs
Authors: Mueller R E , Iannotti E L , Asplund J M
Published: January 2020

Successive changes in aerobic and anaerobic bacterial counts and changes in the generic composition of the epimural community in lambs from 1 to 10 weeks were determined. Bacterial culture counts revealed a predominantly anaerobic community, with the mean anaerobic count being 1.4 X 10(7) CFU/cm2 of tissue surface. The aerobic count was highest at 1 week of age and declined significantly thereafter to a mean of 1.8 X 10(4) CFU/cm2, thus representing only 0.13% of the mean anaerobic count after week 1. Of the 345 strains isolated anaerobically at 1, 2, 4, 6, 8, and 10 weeks of age, 47, 32, 12, 32, 2, and 5% were capable of growth in a partially reduced medium, indicating a reduction in the number of facultative anaerobes with time. The majority of isolated strains were identified as belonging to genera commonly isolated from rumen contents. In some instances, however, strains did not correspond to previously described species, and some genera were present in proportions different from those expected in rumen fluid. At three of the sampling times, one genus was dominant, constituting 45 to 55% of the isolates. These dominant isolates were Streptococcus bovis, Bacteroides sp., and an anaerobic Streptococcus sp. for weeks 1, 2, and 10, respectively. During the transition period (weeks 4 to 8), two or more groups were codominant.
Investigations into the survival of Pseudomonas aeruginosa in poloxamer-iodine
Authors: Anderson R L , Berkelman R L , Mackel D C , Davis B J , Holland B W , Martone W J
Published: January 2020

Laboratory investigations were conducted to study potential mechanisms for prolonged survival of Pseudomonas aeruginosa in poloxamer-iodine (PxI). P. aeruginosa organisms isolated from PxI and adapted for growth in distilled water or found as part of a mixed microbial population from water in a manufacturing plant did not survive more than 15 s after challenge in stock PxI solution. Batches of PxI were compounded in the laboratory to determine the survival and growth of P. aeruginosa during the various stages of preparation. No P. aeruginosa organisms were recovered from the finished product at 1 min after the addition of iodine-iodide. However, we found P. aeruginosa in PxI 48 h after adding sterile PxI to the inside of a naturally contaminated polyvinyl chloride water distribution pipe. These organisms (10(4) CFU/ml) survived for as long as 98 days in contaminated stock PxI after it was removed from the polyvinyl chloride pipe. Both decreasing the free iodine level through addition of potassium iodide and increasing the free iodine level through dilution of the product resulted in an increased length of survival of P. aeruginosa in contaminated PxI solution. Comparative survival studies with pipes of different composition revealed that other materials may exert an effect similar to polyvinyl chloride. We concluded that polyvinyl chloride and perhaps other materials may play an important role in the survival of P. aeruginosa in iodophors and may be one source of resistant microbial populations when used in manufacturing plants which produce these antimicrobial solutions.
Fate of Hydrocarbons During Oily Sludge Disposal in Soil
Authors: Bossert Ingeborg , Kachel Wayne M. , Bartha Richard
Published: January 2020

A 1,280-day laboratory simulation of the “landfarming” process explored the fate in soil of polynuclear aromatics (PNAs) and total extractable hydrocarbon residues originating from the disposal of an oily sludge. In addition to the measurement of CO
2
evolution, periodic analyses of PNAs and hydrocarbons monitored biodegradation activity. The estimation of carbon balance and of soil organic matter assessed the fate of residual hydrocarbons. Seven sludge applications during a 920-day active disposal period were followed by a 360-day inactive “closure” period with no further sludge applications. A burst of CO
2
evolution followed each sludge addition, but substantial amounts of undegraded hydrocarbons remained at the end of the study. Hydrocarbon accumulation did not inhibit biodegradation performance. Conversion of hydrocarbons to CO
2
predominated during active disposal; incorporation into soil organic matter predominated during the closure period. In this sludge, the predominant PNAs were degraded more completely (85%) than total hydrocarbons. Both biodegradation and abiotic losses of three- and four-ring PNAs contributed to this result. Some PNAs with five and six rings were more persistent, but these constituted only a small portion of the PNAs in the sludge. The study confirmed that the microbially mediated processes of mineralization and humification remove sludge hydrocarbons from soils of landfarms with reasonable efficiency.
Heat-induced temperature sensitivity of outgrowing Bacillus cereus spores
Authors: Johnson K M , Busta F F
Published: January 2020

Inactivation of Bacillus cereus spores during cooling (10 degrees C/h) from 90 degrees C occurred in two phases. One phase occurred during cooling from 90 to 80 degrees C; the second occurred during cooling from 46 to 38 degrees C. In contrast, no inactivation occurred when spores were cooled from a maximum temperature of 80 degrees C. Inactivation of spores at a constant temperature of 45 degrees C was induced by initial heat treatments from 80 to 90 degrees C. The higher temperatures accelerated the rate of inactivation. Germination of spores was required for 45 degrees C inactivation to occur; however, faster germination was not the cause of accelerated inactivation of spores receiving higher initial heat treatments. Repair of possible injury was not observed in Trypticase soy broth (BBL Microbiology Systems), peptone, beef extract, starch, or L-alanine at 30 or 35 degrees C. Microscopic evaluation of spores outgrowing at 45 degrees C revealed that when inactivation occurred, outgrowth halted at the swelling stage. Inhibition of protein synthesis by chloramphenicol at the optimum temperature also stopped outgrowth at swelling; thus protein synthesis may play a role in the 45 degree C inactivation mechanism.
Analysis of an Effective Antibiotic (Chaetomacin) Isolated from a Thermophilic
Bacillus
sp. Against Olive Green Mold
Authors: Tautorus T. E. , Townsley P. M.
Published: January 2020

Successful methods to control the damaging weed mold
Chaetomium olivaceum
(olive green mold) in mushroom beds are not known. An effective antibiotic (named chaetomacin) against
C. olivaceum
was isolated from a thermophilic
Bacillus
sp. This compound was shown to be an extremely potent and stable antibiotic, effective over a wide range of both pH (2 to 10) and temperature (−15 to 150°C). Chaetomacin is soluble in most polar solvents and insoluble in nonpolar solvents. It is produced only at mesophilic temperatures and is also active against other
Bacillus
spp. and various eucaryotes, but it demonstrates no activity against gram-negative rods or gram-positive cocci. Final purification of chaetomacin was accomplished through thin-layer chromatography on silica gel analytical plates. Amino acid analysis revealed the antibiotic to be a peptide, acidic in nature. Examination of the literature reveals no other previously isolated antibiotics identical to chaetomacin.
Sea Ice Microbial Communities: Distribution, Abundance, and Diversity of Ice Bacteria in McMurdo Sound, Antarctica, in 1980
Authors: Sullivan Cornelius W. , Palmisano Anna C.
Published: January 2020

An abundant and diverse bacterial community was found within brine channels of annual sea ice and at the ice-seawater interface in McMurdo Sound, Antarctica, in 1980. The mean bacterial standing crop was 1.4 × 10
11
cells m
−2
(9.8 mg of C m
−2
); bacterial concentrations as high as 1.02 × 10
12
cells m
−3
were observed in ice core melt water. Vertical profiles of ice cores 1.3 to 2.5 m long showed that 47% of the bacterial numbers and 93% of the bacterial biomass were located in the bottom 20 cm of sea ice. Ice bacterial biomass concentration was more than 10 times higher than bacterioplankton from the water column. Scanning electron micrographs showed a variety of morphologically distinct cell types, including coccoid, rod, fusiform, filamentous, and prosthecate forms; dividing cells were commonly observed. Approximately 70% of the ice bacteria were free-living, whereas 30% were attached to either living algal cells or detritus. Interactions between ice bacteria and microalgae were suggested by a positive correlation between bacterial numbers and chlorophyll
a
content of the ice. Scanning and transmission electron microscopy revealed a close physical association between epibacteria and a dominant ice alga of the genus
Amphiprora.
We propose that sea ice microbial communities are not only sources of primary production but also sources of secondary microbial production in polar ecosystems. Furthermore, we propose that a detrital food web may be associated with polar sea ice.
Dynamics of the Volatile Organic Substances Associated with Cyanobacteria and Algae in a Eutrophic Shallow Lake
Authors: Jüttner Friedrich
Published: January 2020

The volatile substances present in a eutrophic shallow lake were determined qualitatively and quantitatively during the growing season, allowing a first-time analysis of the dynamics of these compounds in a water body. The major compounds found were β-cyclocitral, α-cyclocitral, β-ionone, 1,3,3-trimethylcyclohexene, 2,2,6-trimethylcyclohexanone, 2,6,6-trimethylcyclohex-2-en-1-one, eucalyptol, geosmin, two argosmin isomers, pent-1-en-3-ol, pent-1-en-3-one, heptadec-1-ene, heptadec-
cis
5-ene, heptadeca-1,
cis
8-diene, decanal, and hexanal. Most of the substances have not been detected before in natural waters. The occurrence of geosmin, the argosmin isomers, heptadec-
cis
5-ene, and an unknown sesquiterpene could clearly be correlated with the appearance of
Aphanizomenon gracile
, as could the occurrence of β-cyclocitral with the appearance of
Microcystis wesenbergii.
The data presented indicate that a rapid metabolism or the elimination of these compounds occurs in lake water.
General method for determining anaerobic biodegradation potential
Authors: Shelton D R , Tiedje J M
Published: January 2020

A simple, generalized method was refined and validated to test whether an organic chemical was susceptible to anaerobic degradation to CH4 + CO2. The method used digested sewage sludge diluted to 10% and incubated anaerobically in 160-ml serum bottles with 50 micrograms of C per ml of test chemical. Biodegradation was determined by the net increase in gas pressure in bottles with test chemicals over the pressure in nonamended sludge bottles. Gas production was measured by gas chromatography and by a pressure transducer. The latter method is recommended because of its speed, accuracy, and low cost. Sewage sludge from municipal digesters with 15- to 30-day retention times was found to be suitable. The sludge could be stored anaerobically at 4 degrees C for up to 4 weeks with satisfactory test results. p-Cresol, phthalic acid, and ethanol are suggested as reference chemicals to confirm sludge activity and method reliability. A revised anaerobic salts medium was developed which minimizes problems of a biological gas production (CO2), avoids precipitation, and meets the requirements of the anaerobic microbiota. When greater than 75% of the theoretical gas production was observed, the chemical was judged to be degradable, and when 30 to 75% of the expected gas was produced, it was termed partially degradable. This method has been tested on more than 100 chemicals of various physical properties and found to reproducibly determine anaerobic biodegradation potential. Of the chemicals tested, 46 were found to be anaerobically degraded. Sludges from nine different municipal treatment plants were surveyed for their ability to degrade nine chemicals which differed in susceptibility to degradation.(ABSTRACT TRUNCATED AT 250 WORDS)
Effect of relative humidity on the airborne survival of rotavirus SA11
Authors: Sattar S A , Ijaz M K , Johnson-Lussenburg C M , Springthorpe V S
Published: January 2020

Rotavirus SA11, suspended in tryptose phosphate broth with 2.5 mg of rhodamine B per ml, was aerosolized (Collison nebulizer) into a rotating drum, and the aerosols were held at 20 +/- 1 degree C with the desired relative humidity (RH). An all-glass impinger with tryptose phosphate broth was used to collect 1-min (5.6-liter) samples of air from the drum. The virus was found to survive best at medium (50 +/- 5%) RH, where its half-life was nearly 40 h. The half-life of the virus at the low (25 +/- 5%) RH level was about 9 h. Even at 72 h of aerosol age, 45 and 21% of the infectious virus remained detectable in the air at the medium and low RH levels, respectively. The high (80 +/- 5%) RH level was found to be the least favorable to the survival of the virus, since 50% of the infectious virus became undetectable within 2 h of aerosolization. In a separate experiment at the midrange RH, 3% of the infectious virus was detectable in the drum air after 223 h (9 days) of aerosol age. Rotaviruses could, therefore, survive in air for prolonged periods, thus making air a possible vehicle for their dissemination.
Composition of Regenerated Cell Walls of Reverting
Aureobasidium pullulans
Protoplasts
Authors: Quigley David R. , Siehr Donald J.
Published: January 2020

Protoplasts of
Aureobasidium pullulans
, formed by treating normal blastospores with polysaccharide-hydrolyzing enzymes, synthesized glycans when incubated in shallow culture. The polysaccharides formed a loose, thick coating on the cells. The glycans that were formed are similar to the glycans in normal cell walls; however, they lack the branching that is normally found. This result is consistent with the findings of others who have studied the cell wall composition of reverting yeast protoplasts.
DNA-DNA Homology Between Lactic Streptococci and Their Temperate and Lytic Phages
Authors: Jarvis Audrey W.
Published: January 2020

Temperate phages were induced from
Streptococcus cremoris
R
1
, BK
5
, and 134. DNA from the three induced phages was shown to be homologous with prophage DNA in the bacterial chromosomes of their lysogenic hosts by the Southern blot hybridization technique.
32
P-labeled DNA from 11 lytic phages which had been isolated on cheese starters was similarly hybridized with DNA from 36 strains of lactic streptococci. No significant homology was detected between the phage and bacterial DNA. Phages and lactic streptococci used included phages isolated in a recently opened cheese plant and all the starter strains used in the plant since it commenced operation. The three temperate phages were compared by DNA-DNA hybridizations with 25 lytic phages isolated on cheese starters. Little or no homology was found between DNA from the temperate and lytic phages. In contrast, temperate phages showed a partial relationship with one another. Temperate phage DNA also showed partial homology with DNA from a number of strains of lactic streptococci, many of which have been shown to be lysogenic. This suggests that many temperate phages in lactic streptococci may be related to one another and therefore may be homoimmune with one another. These findings indicate that the release of temperate phages from starter cells currently in use is unlikely to be the predominant source of lytic phages in cheese plants.
Metabolism of aflatoxin, ochratoxin, zearalenone, and three trichothecenes by intact rumen fluid, rumen protozoa, and rumen bacteria
Authors: Kiessling K H , Pettersson H , Sandholm K , Olsen M
Published: January 2020

The effect of rumen microbes on six mycotoxins (aflatoxin B1, ochratoxin A, zearalenone, T-2 toxin, diacetoxyscirpenol, and deoxynivalenol ) considered to be health risks for domestic animals was investigated. The mycotoxins were incubated with intact rumen fluid or fractions of rumen protozoa and bacteria from sheep and cattle in the presence or absence of milled feed. Rumen fluid had no effect on aflatoxin B1 and deoxynivalenol . The remaining four mycotoxins were all metabolized, and protozoa were more active than bacteria. Metabolism of ochratoxin A, zearalenone, and diacetoxyscirpenol was moderately or slightly inhibited by addition of milled feed in vitro. The capacity of rumen fluid to degrade ochratoxin A decreased after feeding, but this activity was gradually restored by the next feeding time. Ochratoxin A was cleaved to ochratoxin alpha and phenylalanine; zearalenone was reduced to alpha-zearalenol and to a lesser degree to beta-zearalenol; diacetoxyscirpenol and T-2 toxin were deacetylated to monoacetoxyscirpenol and HT-2 toxin, respectively. Feeding of 5 ppm (5 mg/kg) of ochratoxin A to sheep revealed 14 ppb (14 ng/ml) of ochratoxin A and ochratoxin alpha in rumen fluid after 1 h, but neither was detected in the blood. Whether such conversions in the rumen fluid may be considered as a first line of defense against toxic compounds present in the diet is briefly discussed.
Amino acid and lactate catabolism in trimethylamine oxide respiration of Alteromonas putrefaciens NCMB 1735
Authors: Ringø E , Stenberg E , Strøm A R
Published: January 2020

The nonfermentative Alteromonas putrefaciens NCMB 1735 grew anaerobically in defined media with trimethylamine oxide as external electron acceptor. All amino acids tested, except taurine and those with a cyclic or aromatic side chain, were utilized during trimethylamine oxide-dependent anaerobic growth. Lactate, serine, and cysteine (which are easily converted to pyruvate) and glutamate and aspartate (which are easily converted to tricarboxylic acid cycle intermediates) were metabolized at the fastest rate. Growth with lactate as growth-limiting substrate gave rise to the formation of 40 mol% acetate, whereas serine and cysteine were nearly completely oxidized to CO2. Molar growth yields with the latter substrates were the same and were 50% higher than with lactate. This showed that more ATP was formed when acetyl coenzyme A entered the tricarboxylic acid cycle than when it was converted via acetyl phosphate to acetate. Also, growth with formate as substrate indicated that the reduction of trimethylamine oxide to trimethylamine was coupled with energy conservation by a respiratory mechanism.
Bioconversion of Xylan to Triglycerides by Oil-Rich Yeasts
Authors: Fall Ray , Phelps Patricia , Spindler Diane
Published: January 2020

A series of lipid-accumulating yeasts was examined for their potential to saccharify xylan and accumulate triglyceride. Of the genera tested, including
Candida, Cryptococcus, Lipomyces, Rhodosporidium, Rhodotorula
, and
Trichosporon
, only
Cryptococcus
and
Trichosporon
isolates saccharified xylan. All of the strains could assimilate xylose and accumuate triglyceride under nitrogen-limiting conditions. Strains of
Cryptococcus albidus
were found to be especially useful for a one-step saccharification of xylan coupled to triglyceride synthesis.
Cryptococcus terricolus
, a strain constitutive for lipid accumulation, lacked extracellular xylanase, but did assimilate xylose and xylobiose and was able to continuously convert xylan to triglyceride if the culture medium was supplemented with xylanase.