bluuebunny/crossref_metadata_2025 huggingface dataset:
Associations between milk fat content and obesity, 1999 to 2016
Authors: White Michelle J. , Armstrong Sarah C. , Kay Melissa C. , Perrin Eliana M. , Skinner Asheley
Published: January 2020

Background

The relationship between milk fat content and body mass index (BMI) remains unclear. The objective of this study was to determine if milk fat content is associated with obesity in children, adolescents and young adults.

Methods

We used repeated cross sections of National Health and Nutrition Examination Survey (NHANES), 1999 to 2016. Using logistic regression, we measured associations between first milk consumed after formula/breast milk (whole, 2%, 1%, or fat‐free) and weight status (≥85th to <95th BMI percentile, overweight; ≥95th BMI percentile, obesity) among children 2 to 6 years (n = 8367). We also assessed associations between current milk type and weight status among those 2 to 20 years of age (n = 26 750).

Results

Children 2 to 6 years with obesity were less likely to have been weaned to whole milk versus healthy weight children (adjusted odds ratio [aOR], 0.77; 95% CI, 0.60‐0.98; P = .031). Individuals 2 to 20 years with overweight or obesity were less likely to drink whole milk as their current milk and more likely to drink fat‐free or 1% milk compared with healthy weight children.

Conclusions

Whole milk consumers are less likely to have obesity. It is unclear whether this relationship is causal or a reflection of United States Department of Agriculture recommendations. Further examination of the factors that influence milk choice among diverse cohorts would lend clarity to this important issue.
Asian management of hypertension: Current status, home blood pressure, and specific concerns in Pakistan
Authors: Siddique Saulat
Published: January 2020

Hypertension has reached epidemic proportions in Pakistan, and cardiovascular disease accounts for half of all non‐communicable diseases in the country. Although home blood pressure monitoring (HBPM) is being used in Pakistan, it is not routine practice, and cost is a major barrier to uptake. Other barriers include a lack of awareness of the utility of HBPM among patients and physicians, low education literacy levels in the general population, variability of results obtained using HBPM due to the presence of a large number of non‐validated monitors on the market, and a lack of awareness among physicians about the correct methodology for using HBPM. The Pakistan Hypertension League (PHL) does recommend use of a validated digital HBPM device for BP measurement. Recent data suggest that calcium channel blockers are the most commonly used antihypertensive agents, with ß‐blockers and angiotensin receptor blockers also widely used. Traditional medicine remains popular in Pakistan because it is more accessible, especially in rural areas, and is less expensive than conventional antihypertensives. The growing burden of hypertension and cardiovascular disease in Pakistan is compounded by the poor socioeconomic status of a fairly large proportion of the population, and lack of literacy and education. There is also a shortage of adequately trained medical personnel to take care of the increasing number of patients. The PHL and Pakistan Cardiac Society are working to increase awareness of hypertension at both the population and government levels.
Assessment of flash flood susceptibility potential in Moldavian Plain (Romania)
Authors: Iosub Marina , Minea Ionuţ , Chelariu Oana E. , Ursu Adrian
Published: January 2020

Concentration of time (Tc) is a frequently used parameter in the evaluation of the hydrological response of different sizes hydrographic basin in case of rainfall events. The present study is innovative, because it has created an index that identifies the small‐sized hydrographic basins that are exposed to the risk of flooding. The Moldavian Plain is an area located in the northeast of Romania where the local population is frequently affected by floods and flash floods caused by heavy rainfall events. The main purpose of the current study is to identify the settlements located in the small‐sized hydrographic basins, which are associated with low concentration times and powerful surface runoff. The empirical method was applied in order to calculate the Tc for rainfall water, for each drainage basin, for a time class less than 6 hr. Calculations of the runoff water were also done for a theoretical extreme precipitation event, corresponding to the 1% occurrence probability. A total number of 312 basins were identified that are smaller than 30 km2, out of which 112 have Tc of less than 6 hr. These basins, in particular, pose flood risk for 12.4% of the villages and towns in the study area.
The effects of nanoemulsions based on citrus essential oils on the formation of biogenic amines in trout fillets stored at 4 ± 2°C
Authors: Kosker Ali Rıza
Published: January 2020

The influences of nanoemulsions based on citrus peel (orange, lemon, mandarin, and grapefruit) essential oils on the biogenic amine (BA) formation in rainbow trout (Oncorhynchus mykiss) fillets stored 4 ± 2°C were investigated. The results demonstrated that main BAs in the trout fillets were putrescine, cadaverine, spermidine, spermine, serotonin, tyramine, dopamine, and agmatine. It was determined that nanoemulsion application had generally suppressive effect on the formation of BAs during storage. It was also found that especially orange and lemon nanoemulsion groups were effective on histamine formation. Histamine values ranged from 0.00 to 4.08 in all groups during storage and the levels were below the limit values of FDA and EU throughout the storage period for all treatment groups. Similarly, Quality Index (QI) values of BAs were found to be below legal limits in all groups. Consequently, it was found that nanoemulsions prepared from essential oils kept the BA formation at a lower level during storage.
The iliosacral joint in lizards: an osteological and histological analysis
Authors: Paparella Ilaria , LeBlanc Aaron R. H. , Doschak Michael R. , Caldwell Michael W.
Published: January 2020

The development of the iliosacral joint (ISJ) in tetrapods represented a crucial step in the evolution of terrestrial locomotion. This structure is responsible for transferring forces between the vertebral column and appendicular skeleton, thus supporting the bodyweight on land. However, most research dealing with the water‐to‐land transition and biomechanical studies in general has focused exclusively on the articulation between the pelvic girdle and femur. Our knowledge about the contact between the pelvic girdle and vertebral column (i.e. the ISJ) at a tissue level is restricted so far to human anatomy, with little to no information available on other tetrapods. This lack of data limits our understanding of the development and evolution of such a key structure, and thus on the pattern and processes of the evolution of terrestrial locomotion. Therefore, we investigated the macro‐ and microanatomy of the ISJ in limb‐bearing squamates that, similar to most non‐mammalian, non‐avian tetrapods, possess only two sacral ribs articulating with the posterior process of the ilium. Using a combination of osteology, micro‐computed tomography and histology, we collected data on the ISJ apparatus of numerous specimens, sampling different taxa and different ontogenetic stages. Osteologically, we recorded consistent variability in all three processes of the ilium (preacetabular, supracetabular and posterior) and sacral ribs that correlate with posture and locomotion. The presence of a cavity between the ilium and sacral ribs, abundant articular cartilage and fibrocartilage, and a surrounding membrane of dense fibrous connective tissue allowed us to define this contact as a synovial joint. By comparison, the two sacral ribs are connected to each other mostly by dense fibrous tissue, with some cartilage found more distally along the margins of the two ribs, defining this joint as a combination of a syndesmosis and synchondrosis. Considering the intermediary position of the ISJ between the axial and appendicular skeletons, the shape of the articular surfaces of the sacral ribs and ilium, and the characteristics of the muscles associated with this structure, we argue that the mobility of the ISJ is primarily driven by the movements of the hindlimb during locomotion. We hypothesize that limited torsion of the ilium at the ISJ happens when the hip is abducted, and the joint is likely able to absorb the compressional and extensional forces related to the protraction and retraction of the femur. The mix of fibres and cartilage between the two sacral ribs instead serves primarily as a shock absorber, with the potential for limited vertical translation during locomotion.
A‐scan ultrasonography and optic nerve sheath diameter evaluation in children with acute liver failure
Authors: De Bernardo Maddalena , Vitiello Livio , Capone Michela , Rosa Nicola
Published: January 2020

In this Letter to the Editor we would like to comment the article by Das and colleagues, concerning the optic nerve sheath diameter evaluation with ultrasonography in children with acute liver failure. In particular, this letter highlights several limitations in the use of B scan for such a purpose and suggests a more precise assessment with the standardized A scan technique.
Grassland conversion along a climate gradient in northwest China: Implications for soil carbon and nutrients
Authors: Huang Xiaomin , Song Zhenwei , van Groenigen Kees Jan , Xu Zhiyu , Huang Bo , Zhang Yi , Hang Xiaoning , Tan Shuhao , Zhang Degang , Zhang Weijian
Published: January 2020

Soil organic carbon (SOC) stocks and nutrient availability are key indicators of soil quality, and both can be influenced by land‐use change. However, it is still unclear whether the impact of land‐use change on SOC and nutrient stocks differs between ecoregions. Grasslands near the northeast border of the Qinghai‐Tibetan Plateau (QTP) occur across several ecoregions that have recently been subjected to substantial land‐use change. Based on long‐term land‐use history, we conducted a field investigation comparing soil C and nutrient stocks between natural grassland (NGL) and three types of converted grassland (agricultural grassland, AGL; farmland, FL; and abandoned farmland, AFL) in three ecoregions along a climate gradient: alpine meadow, temperate steppe and temperate desert. Compared with NGL, soil C stocks in converted grasslands were 22%–30% lower in the alpine meadow, but 60–82% higher in the temperate steppe and 6%–76% higher in the temperate desert. Converted grasslands also contained higher stocks of available nitrogen and phosphorus than NGL in the temperate steppe and desert. Soils (0–40 cm) in NGL contained 14.8 ± 0.1 kg C m−2 in alpine meadow, 6.7 ± 0.6 kg C m−2 in temperate steppe and 1.7 ± 0.3 kg C m−2 in temperate desert. Together, our results indicate that the responses of soil C and nutrients to grassland conversion differed between ecoregions. Thus, to optimize soil C sequestration rates and overall soil quality, we suggest that land‐use policies in this area should take into account local environmental conditions.
Improvement in Savonius Wind Turbines Efficiency by Modification of Blade Designs—A Numerical Study
Authors: Laws Praveen , Saini Jaskaran Singh , Kumar Ajit , Mitra Santanu
Published: January 2020

Savonius wind turbines are special class of vertical axis wind turbines (VAWTs). These are low-cost drag-driven turbines and are known to be inefficient. It is proposed in this study that a simple modification to the turbine blade design can yield a significant improvement in power efficiency. The performance of the new design is extensively studied on openfoam-v1812, a popular open source computational fluid dynamics (CFD) library. The flow equations coupled with equations of rotation of the turbine are solved on an overset mesh framework. This study also serves as a validation of recently released overset support in openfoam. The turbulence is incorporated by coupling Reynolds-averaged Navier–Stokes (RANS) with shear stress transport (SST) κ − ω eddy viscosity turbulence model. The turbulence parameters are set to produce a flow with the Reynolds number, Re = 4.8 × 105. To have better confidence in simulations, this study also presents a comparison of numerical flow over conventional Savonius turbine designs with the published data. It is observed that a majority of CFD analysis on wind turbine designs are performed for the fixed tip speed ratio on a traditional static mesh structure. But, in this CFD study, a wind-driven rotation of Savonius turbine is simulated on an overset dynamics approach. The results of the study are compared and discussed based on the predicted moment and power coefficients, pressure variation on the blades, flow velocity field, and wake analysis. The study indicates that the blade design presented here has a potential to increase the power efficiency of a Savonius wind turbine by 10–28%.
Feasibility and Sensitivity Analysis of a Hybrid Photovoltaic/Wind/Biogas/Fuel-Cell/Diesel/Battery System for Off-Grid Rural Electrification Using homer
Authors: Anwar Khalid , Deshmukh Sandip , Mustafa Rizvi Saad
Published: January 2020

Integrating renewable energy technologies in a single system is becoming more reliable to meet electrical demand of remote locations. Here, integration and the optimal use of various available energy resources in a stand-alone microgrid are investigated. An integrated renewable energy system (IRES) approach has been proposed and analyzed using homer software. Seven scenarios with different combinations of energy sources and storage systems have been investigated based on their levelized cost of energy (LCOE) supply and net present cost (NPC). The proposed IRES, which includes photovoltaic (PV), wind, and biogas, gives the least LCOE as $0.207/kW h without any policy intervention. This LCOE reduces to $0.12/kW h with policy intervention and consideration of carbon abetment cost. Moreover, sensitivity analysis has been carried out with variation in load, solar radiation, and wind speed. The NPC is found to be most sensitive to the variation of load and least sensitive to the variation of wind speed.
Heat Transfer-Friction Factor and Correlations for Wavy Porous Screens as Inserts in Channel Thermal Performance
Authors: Torr A. , Mahmood G. I. , Cramer L.
Published: January 2020

Structural inserts are employed to enhance the heat transfer in channel flow with the expense of thermal performance. The present investigation employs the wavy porous screens as inserts in an air channel and measures the pressure drop and heat transfer along the channel. The wave vectors are parallel to the flow and in point contact at the tips with the channel walls. The pores in the insert generate turbulence to enhance the heat transfer from the channel walls with a moderate pressure penalty because of the low blockage ratio. The objectives are to investigate the effects of wavelength (λ), porosity (ξ), and height (H) of the sinusoidal wave of the insert as well as the Reynolds number (Re) on the friction factors (f) and Nusselt numbers (Nu). Twelve inserts are formed from the flat metal mesh screens for testing between the Reynolds number (Re) of 400 and 35,000. The results of (f, Nu) and smooth channel-based enhancements (f/f0, Nu/Nu0) are affected the most by Re followed by λ and then ξ. The values of both (f/f0, Nu/Nu0) increase significantly as the Reynolds number increases in Re < 3000. However, both the (f/f0, Nu/Nu0) decrease little as both the (λ, ξ) increase at all Re. The performance factor index, (Nu/Nu0)/(f/f0)(1/3) > 1.0 irrespective of (λ, ξ, H) only when Re is about 3000. The correlations developed for the f, Nu, and performance factor provide reasonable predictions of the experimental results.
Case Commentary: Delayed Cerebral Vasculitis Associated with the Development of Ceftriaxone-Resistant Pneumococcal Meningitis
Authors: Hasbun Rodrigo
Published: January 2020

Mizrahi and colleagues present a well-described case of the emergence of drug resistance in
Streptococcus pneumoniae
meningitis during therapy with ceftriaxone monotherapy with a low bactericidal concentration in the cerebrospinal fluid. Adherence to international guidelines could possibly have prevented the emergence of this resistant isolate and the adverse outcome.
Bioaccumulation of the Herbicide Diclofop in Extracellular Polymers and Its Utilization by a Biofilm Community during Starvation
Authors: Wolfaardt G M , Lawrence J R , Robarts R D , Caldwell D E
Published: January 2020

Continuous-flow cell systems were used to cultivate a degradative biofilm community with the herbicide diclofop methyl as the sole carbon and energy source. The aromatic character of this compound and its breakdown products enabled direct visualization of their accumulation in the biofilm matrix. This accumulation could be inhibited by addition of a more labile carbon source to the culture medium or by inhibition of cell activity. The fluorescence of diclofop-grown biofilms remained constant after 14 to 21 days but decreased with time when diclofop was omitted from the irrigation solution. However, this decrease was inhibited by cyanide, indicating either utilization or release of accumulated diclofop when the cells were viable. Subsequent experiments with [(sup14)C]diclofop also indicated that decreased fluorescence in the absence of an exogenous carbon source resulted from degradation of adsorbed diclofop and its breakdown products by the biofilm bacteria. These results demonstrate that biofilm exopolymers can facilitate storage of nutrients for subsequent mineralization during periods of carbon limitation.
Influence of Ammonium Salts and Cane Molasses on Growth of Alcaligenes eutrophus and Production of Polyhydroxybutyrate
Authors: Beaulieu M , Beaulieu Y , Melinard J , Pandian S , Goulet J
Published: January 2020

The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were obtained with ammonium sulfate; however, NH(inf4)(sup+) concentrations between 0.5 and 1.5 g/liter showed no significant difference. Ammonium sulfate was therefore used as the sole source of NH(inf4)(sup+) for experiments with cane molasses as the growth activator. Optimal growth and PHB production were obtained with 0.3% molasses. However, the yields of biomass (39 to 48%) and PHB (17 to 26%) varied significantly among the different ammonium substrates and cane molasses concentrations.
Purification and characterization of alpha-L-arabinofuranosidase from Bacillus stearothermophilus T-6
Authors: Gilead S , Shoham Y
Published: January 2020

Bacillus stearothermophilus T-6 produced an alpha-L-arabinofuranosidase when grown in the presence of L-arabinose, sugar beet arabinan, or oat spelt xylan. At the end of a fermentation, about 40% of the activity was extracellular, and enzyme activity in the cell-free supernatant could reach 25 U/ml. The enzymatic activity in the supernatant was concentrated against polyethylene glycol 20000, and the enzyme was purified eightfold by anion-exchange and hydrophobic interaction chromatographies. The molecular weight of T-6 alpha-L-arabinofuranosidase was 256,000, and it consisted of four identical subunits as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration. The native enzyme had a pI of 6.5 and was most active at 70 degrees C and at pH 5.5 to 6.0. Its thermostability at pH 7.0 was characterized by half-lives of 53, 15, and 1 h at 60, 65, and 70 degrees C, respectively. Kinetic experiments at 60 degrees C with p-nitrophenyl alpha-L-arabinofuranoside as a substrate gave a Vmax, a Km, and an activation energy of 749 U/mg, 0.42 mM, and 16.6 kcal/mol, (ca. 69.5 kJ/mol), respectively. The enzyme had no apparent requirement for cofactors, and its activity was strongly inhibited by 1 mM Hg2+. T-6 alpha-L-arabinofuranosidase released L-arabinose from arabinan and had low activity on oat spelt xylan. The enzyme acted cooperatively with T-6 xylanase in hydrolyzing oat spelt xylan, and L-arabinose, xylose, and xylobiose were detected as the end reaction products.(ABSTRACT TRUNCATED AT 250 WORDS)
Application of ribotyping for differentiating Vibrio cholerae non-O1 isolated from shrimp farms in Thailand
Authors: Dalsgaard A , Echeverria P , Larsen J L , Siebeling R , Serichantalergs O , Huss H H
Published: January 2020

A collection of 143 Vibrio cholerae non-O1 strains isolated from shrimp farms in Thailand were characterized and grouped by ribotyping. Sixty-four ribotypes were distinguished following digestion of chromosomal DNA with the restriction enzyme BglI, and the reproducibility of the method was 100%. There was no correlation between specific ribotype distributions and the locations of the shrimp farms. Ribotype similarity was examined by cluster analysis, and two main groups with 10 and 54 ribotypes, respectively, were found. Correlation between ribotype and O-antigen expression was shown to exist among those isolates tested. Ribotyping appears to be a suitable method for differentiating environmental V. cholerae non-O1 strains, and comparison of ribotype patterns showed a high degree of genetic divergence within V. cholerae non-O1.
Adhesion of germlings of Botrytis cinerea
Authors: Doss R P , Potter S W , Soeldner A H , Christian J K , Fukunaga L E
Published: January 2020

Adhesion of conidia and germlings of the facultative plant parasite Botrytis cinerea occurs in two distinct stages. The first stage, which occurs immediately upon hydration of conidia and is characterized by relatively weak adhesive forces, appears to involve hydrophobic interactions (R. P. Doss, S. W. Potter, G. A. Chastagner, and J. K. Christian, Appl. Environ. Microbiol. 59:1786-1791, 1993). The second stage of adhesion, delayed adhesion, occurs after viable conidia have been incubated for several hours under conditions that promote germination. At this time, the germlings attach strongly to either hydrophobic or hydrophilic substrata. Delayed adhesion involves secretion of an ensheating film that remains attached to the substratum upon physical removal of the germlings. This fungal sheath, which can be visualized by using interference-contrast light microscopy, scanning electron microscopy, or atomic force microscopy, is 25 to 60 nm thick in the region immediately adjacent to the germ tubes. Germlings are resistant to removal by boiling or by treatment with a number of hydrolytic enzymes, 2.0 M periodic acid, or 1.0 M sulfuric acid. They are readily removed by brief exposure to 1.25 N NaOH. A base-soluble material that adheres to culture flask walls in short-term liquid cultures of B. cinerea is composed of glucose (about 30%), galactosamine (about 3%), and protein (30 to 44%).
Occurrence of high-level aminoglycoside resistance in environmental isolates of enterococci
Authors: Rice E W , Messer J W , Johnson C H , Reasoner D J
Published: January 2020

High-level resistance to aminoglycosides was observed in environmental isolates of enterococci. Various aquatic habitats, including agricultural runoff, creeks, rivers, wastewater, and wells, were analyzed. Strains of Enterococcus faecalis, E. faecium, E. gallinarum, and other Enterococcus spp. demonstrated multiple antibiotic resistance patterns to aminoglycosides.
Transformation of (sup14)C-Lignin-Labeled Cell Walls of Wheat by Syntrophococcus sucromutans, Eubacterium oxidoreducens, and Neocallimastix frontalis
Authors: Bernard-Vailhe M A , Besle J M , Dore J
Published: January 2020

Wheat cell walls, saponified or not, labeled with [U-(sup14)C]phenylalanine or [O-methyl-(sup14)C]sinapate were fermented by Neocallimastix frontalis or Syntrophococcus sucromutans plus Eubacterium oxidoreducens or a mixed culture. Phenolics were less solubilized but more transformed by bacteria than by the fungus, and mineralization was slight. S. sucromutans O-demethylated [O-methyl-(sup14)C]syringyl lignins, yielding labeled acetate.
Sequence variability in homologs of the aflatoxin pathway gene aflR distinguishes species in Aspergillus section Flavi
Authors: Chang P K , Bhatnagar D , Cleveland T E , Bennett J W
Published: January 2020

The Aspergillus parasiticus aflR gene, a gene that may be involved in the regulation of aflatoxin biosynthesis, encodes a putative zinc finger DNA-binding protein. PCR and sequencing were used to examine the presence of aflR homologs in other members of Aspergillus Section Flavi. The predicted amino acid sequences indicated that the same zinc finger domain, CTSCASSKVRCTKEKPACARCIERGLAC, was present in all of the Aspergillus sojae, Aspergillus flavus, and Aspergillus parasiticus isolates examined and in some of the Aspergillus oryzae isolates examined. Unique base substitutions and a specific base deletion were found in the 5' untranslated and zinc finger region; these differences provided distinct fingerprints. A. oryzae and A. flavus had the T-G-A-A-X-C fingerprint, whereas A. parasiticus and A sojae had the C-C-C-C-C-T fingerprint at the corresponding positions. Specific nucleotides at positions -90 (C or T) and -132 (G or A) further distinguished A. flavus from A. oryzae and A. parasiticus from A. sojae, respectively. A sojae ATCC 9362, which was previously designated A. oryzae NRRL 1988, was determined to be a A. sojae strain on the basis of the presence of the characteristic fingerprint, A-C-C-C-C-C-C-T. The DNAs of other members of Aspergillus Section Flavi, such as Aspergillus nomius and Aspergillus tamarii, and some isolates of A. oryzae appeared to exhibit low levels of similarity to the A. parasiticus aflR gene since low amounts of PCR products or no PCR products were obtained when DNAs from these strains were used.
Modulation of Carbon and Electron Flow in Clostridium acetobutylicum by Iron Limitation and Methyl Viologen Addition
Authors: Peguin S , Soucaille P
Published: January 2020

The metabolic flexibility of Clostridium acetobutylicum during growth on glucose with methyl viologen addition (1 mM) and/or iron limitation was examined in batch cultures at pH 5.5. The physiological effects of iron limitation and methyl viologen addition are additive, suggesting that they have different and complementary sites of action.
Specific oligonucleotide primers for detection of lecithinase-positive Bacillus spp. by PCR
Authors: Schraft H , Griffiths M W
Published: January 2020

An assay based on the PCR has been developed to facilitate detection and identification of Bacillus cereus in foods. Three primers for the PCR have been designed within the sequence for cereolysin AB, a cytolytic determinant that encodes lecithin-hydrolyzing and hemolytic activities of B. cereus. With the PCR and hybridization, the specificity of the primers was tested with 39 isolates of the B. cereus group, with 17 other Bacillus spp., and with 21 non-Bacillus strains. Results demonstrate a high specificity of the three oligonucleotides for isolates of the B. cereus group. With a combined PCR-hybridization assay, the detection limit for B. cereus in artificially contaminated milk was 1 CFU/ml of milk.
Lignin Peroxidases, Manganese Peroxidases, and Other Ligninolytic Enzymes Produced by Phlebia radiata during Solid-State Fermentation of Wheat Straw
Authors: Vares T , Kalsi M , Hatakka A
Published: January 2020

The white rot fungus Phlebia radiata 79 (ATCC 64658) produces lignin peroxidase (LiP), manganese peroxidase (MnP), glyoxal oxidase (GLOX), and laccase in the commonly used glucose low-nitrogen liquid medium. However, the enzymes which this fungus utilizes for selective removal of lignin during degradation of different lignocellulosic substrates have not been studied before. Multiple forms of LiP, MnP, GLOX, and laccase were purified from P. radiata culture extracts obtained after solid-state fermentation of wheat straw. However, the patterns of extracellular lignin-modifying enzymes studied were different from those of the enzymes usually found in liquid cultures of P. radiata. Three LiP isoforms were purified. The major LiP isoform from solid-state cultivation was LiP2. LiP3, which has usually been described as the major isoenzyme in liquid cultures, was not expressed during straw fermentation. New MnP isoforms have been detected in addition to the previously reported MnPs. GLOX was secreted in rather high amounts simultaneously with LiP during the first 2 weeks of growth. GLOX purified from P. radiata showed multiple forms, with pIs ranging from 4.0 to 4.6 and with a molecular mass of ca. 68 kDa.
Recombinant infectious hematopoietic necrosis virus and viral hemorrhagic septicemia virus glycoprotein epitopes expressed in Aeromonas salmonicida induce protective immunity in rainbow trout (Oncorhynchus mykiss)
Authors: Noonan B , Enzmann P J , Trust T J
Published: January 2020

Fragments of the glycoprotein genes of viral hemorrhagic septicemia virus (VHSV) and infectious hematopoietic necrosis virus (IHNV) were cloned into a bacterial broad-host-range expression vector under the control of the plac promoter. Western blot (immunoblot) analysis with monoclonal antibodies specific to the glycoproteins demonstrated the inducible expression of the fusion proteins in Escherichia coli. Aeromonas salmonicida is the causative agent of furunculosis in salmonid fish. It was confirmed that an avirulent strain of A. salmonicida, A440, which contains a deletion in the structural gene for the paracrystalline surface protein array, will provide protective immunity against furunculosis when used as a live attenuated vaccine. The plasmid-encoded viral epitopes were then mobilized into A440 for use as a shuttle system for the expression of fragments of the glycoprotein genes of IHNV and VHSV. Vaccination of rainbow trout with A440 containing the viral epitopes resulted in the development of protective immunity against both VHSV and IHNV. This indicates that the use of cloned fragments of the glycoproteins and the use of A. salmonicida as a shuttle system constitute a feasible approach to fish vaccine development.
Growth Kinetics of Thiobacillus thiooxidans on the Surface of Elemental Sulfur
Authors: Konishi Y , Asai S , Yoshida N
Published: January 2020

The growth kinetics of Thiobacillus thiooxidans on elemental sulfur in batch cultures at 30(deg)C and pH 1.5 was studied by measuring the time courses of the concentration of adsorbed cells on sulfur, the concentration of free cells suspended in liquid medium, and the amount of sulfur oxidized. As the elemental sulfur was oxidized to sulfate ions, the surface concentration of adsorbed cells per unit mass of sulfur approached a maximum value (maximum adsorption capacity of sulfur particles) whereas the concentration of free cells continued to increase with time. There was a close relationship between the concentrations of free and adsorbed cells during the microbial sulfur oxidation, and the two cell concentrations were well correlated by the Langmuir isotherm with adsorption equilibrium constant K(infA) and maximum adsorption capacity X(infAm) of 2.10 x 10(sup-9) ml per cell and 4.57 x 10(sup10) cells per g, respectively. The total concentration of free and adsorbed cells increased in parallel with the amount of sulfate formed. The total growth on elemental sulfur gave a characteristic growth curve in which a linear-growth phase followed the period of an initial exponential phase. The batch rate data collected under a wide variety of inoculum levels (about 10(sup5) to 10(sup8) cells per ml) were consistent with a kinetic model assuming that the growth rate of adsorbed bacteria is proportional to the product of the concentration, X(infA), of adsorbed cells and the fraction, (theta)(infV), of adsorption sites unoccupied by cells. The kinetic and stoichiometric parameters appearing in the model were estimated from the experimental data, and the specific growth rate, (mu)(infA), and growth yield, Y(infA), were 2.58 day(sup-1) and 2.05 x 10(sup11) cells per g, respectively. The proposed model and the parameter values allowed us to predict quantitatively the surface attachment of T. thiooxidans cells on elemental sulfur and the bacterial growth in both initial exponential and subsequent linear phases. The transition from exponential to linear growth was a result of two competing factors: an increase in the adsorbed-cell concentration, X(infA), permitted a decrease in the unoccupied-site fraction, (theta)(infV).
Uptake and retention of Vibrio cholerae O1 in the Eastern oyster, Crassostrea virginica
Authors: Murphree R L , Tamplin M L
Published: January 2020

Vibrio cholerae 01, the causative agent of cholera, is known to persist in estuarine environments as endogenous microflora. The recent introduction of V. cholerae 01 into estuaries of the North and South American continents has stimulated the need to determine the effect of controlled purification on reducing this pathogen in edible molluscan shellfish. Experiments defined parameters for the uptake and retention of V. cholerae 01 in tissues of Crassostrea virginica, and these parameters were compared with those for Escherichia coli and Salmonella tallahassee, bacteria which are usually eliminated from moderately contaminated shellfish within 48 h. Oysters accumulated greater concentrations of V. cholerae 01 than E. coli and S. tallahassee. When V. cholerae 01 was exposed to controlled purification at 15, 19 and 25 degrees C over 48 h, it persisted in oysters at markedly higher levels than E. coli and S. tallahassee. The concentration of a V. cholerae 01-specific agglutinin did not positively correlate with the uptake or retention of V. cholerae 01. These data show that state and federally approved controlled purification techniques are not effective at reducing V. cholerae 01 in oysters.
Contact angle measurement and cell hydrophobicity of granular sludge from upflow anaerobic sludge bed reactors
Authors: Daffonchio D , Thaveesri J , Verstraete W
Published: January 2020

The contact angle, which is generally used to evaluate the hydrophobicities of pure bacterial strains and solid surfaces, was used to study mixed cell cultures of bacteria involved in anaerobic digestion. Previously published data and data from this study showed that most acidogens are hydrophilic (contact angle, <45(deg)) but most of the acetogens and methanogens isolated from granular sludge are hydrophobic (contact angle, >45(deg)). The hydrophobicities of mixtures of hydrophilic and hydrophobic cells were found to be linearly correlated with the cell mixing ratio. The hydrophobicities of cells present in effluents from upflow anaerobic sludge bed reactors which were treating different types of substrates were different depending on the reactor conditions. When the reactor liquid had a high surface tension, cells sloughing off from sludge granules, as well as cells present on the outer surfaces of the granules, were hydrophobic. Short-term batch enrichment cultures revealed that proteins selected for highly hydrophilic cells. Long-term in-reactor enrichment cultures revealed that sugars selected for hydrophilic acidogens on the surfaces of the granules, while fatty acids tended to enrich for hydrophobic methanogens. When linear alkylbenzenesulfonate was added, the cells on the surfaces of granules became more hydrophilic. Control tests performed with pure cultures revealed that there was no change in the surface properties due to linear alkylbenzenesulfonate; hence, the changes in the wash-out observed probably reflect changes in the species composition of the microbial association. A surface layer with moderate hydrophobicity, a middle layer with extremely high hydrophobicity, and a core with high hydrophobicity could be distinguished in the grey granules which we studied.
Granulation and sludge bed stability in upflow anaerobic sludge bed reactors in relation to surface thermodynamics
Authors: Thaveesri J , Daffonchio D , Liessens B , Vandermeren P , Verstraete W
Published: January 2020

Adhesion of bacteria involved in anaerobic consortia was investigated in upflow anaerobic sludge bed reactors and was related to surface thermodynamics. The adhesion of hydrophilic cells appeared to be enhanced at a low liquid surface tension ((gamma)(infLV)), while the adhesion of hydrophobic cells was favored at a high (gamma)(infLV). Growth in protein-rich growth media resulted in low granular biomass yields; addition of polycations, such as poly-l-lysine and chitosan, increased the (gamma)(infLV) and the granular biomass yield. On the basis of the results of activity tests and microbial counts with wash-out cells, we identified two types of structured granules that were related to the influence of (gamma)(infLV). In one type of granules, hydrophilic acidogens surrounded a more hydrophobic methanogenic association. These granules were selected at a low (gamma)(infLV) provided that carbohydrates were available as substrates. The other type of granules was selected at a high (gamma)(infLV); hydrophobic cells (i.e., methanogens) were predominant throughout these granules. The granules which had acidogens as solid-phase emulsifiers around a methanogenic association appeared to allow more stable reactor performance. Decreasing the (gamma)(infLV) in the reactor by adding trace amounts of a surfactant also increased reactor stability.
Use of a fluorogenic probe in a PCR-based assay for the detection of Listeria monocytogenes
Authors: Bassler H A , Flood S J , Livak K J , Marmaro J , Knorr R , Batt C A
Published: January 2020

A PCR-based assay for Listeria monocytogenes that uses the hydrolysis of an internal fluorogenic probe to monitor the amplification of the target has been formatted. The fluorogenic 5' nuclease PCR assay takes advantage of the endogenous 5' --> 3' nuclease activity of Taq DNA polymerase to digest a probe which is labelled with two fluorescent dyes and hybridizes to the amplicon during PCR. When the probe is intact, the two fluorophores interact such that the emission of the reporter dye is quenched. During amplification, the probe is hydrolyzed, relieving the quenching of the reporter and resulting in an increase in its fluorescence intensity. This change in reporter dye fluorescence is quantitative for the amount of PCR product and, under appropriate conditions, for the amount of template. We have applied the fluorogenic 5' nuclease PCR assay to detect L. monocytogenes, using an 858-bp amplicon of hemolysin (hlyA) as the target. Maximum sensitivity was achieved by evaluating various fluorogenic probes and then optimizing the assay components and cycling parameters. With crude cell lysates, the total assay could be completed in 3 h with a detection limit of approximately 50 CFU. Quantification was linear over a range of 5 x 10(1) to 5 x 10(5) CFU.
A Long-Chain Secondary Alcohol Dehydrogenase from Rhodococcus erythropolis ATCC 4277
Authors: Ludwig B , Akundi A , Kendall K
Published: January 2020

A NAD-dependent secondary alcohol dehydrogenase has been purified from the alkane-degrading bacterium, Rhodococcus erythropolis ATCC 4277. The enzyme was found to be active against a broad range of substrates, particularly long-chain secondary aliphatic alcohols. Although optimal activity was observed with linear 2-alcohols containing between 6 and 11 carbon atoms, secondary alcohols as long as 2-tetradecanol were oxidized at 25% of the rate seen with mid-range alcohols. The purified enzyme was specific for the S-(+) stereoisomer of 2-octanol and had a specific activity for 2-octanol of over 200 (mu)mol/min/mg of protein at pH 9 and 37(deg)C, 25-fold higher than that of any previously reported S-(+) secondary alcohol dehydrogenase. Linear primary alcohols containing between 3 and 13 carbon atoms were utilized 20- to 40-fold less efficiently than the corresponding secondary alcohols. The apparent K(infm) value for NAD(sup+) with 2-octanol as the substrate was 260 (mu)M, whereas the apparent K(infm) values for the 2-alcohols ranged from over 5 mM for 2-pentanol to less than 2 (mu)M for 2-tetradecanol. The enzyme showed moderate thermostability (half-life of 4 h at 60(deg)C) and could potentially be useful for the synthesis of optically pure stereoisomers of secondary alcohols.
Microbial degradation of monoterpenes in the absence of molecular oxygen
Authors: Harder J , Probian C
Published: January 2020

Anaerobic degradation of natural monoterpenes by microorganisms was evaluated by using Pseudomonas citronellolis DSM 50332 and enrichment cultures containing nitrate as an electron acceptor. P. citronellolis grew anaerobically on 3,7-dimethyl-1-octanol and citronellol but not on geraniol, nerol, and alicyclic monoterpenes. In contrast, several a-, mono-, and bicyclic monoterpenes supported microbial growth and denitrification in enrichment cultures. We found that consumption of linalool, menthol, menth-1-ene, alpha-phellandrene, limonene, 2-carene, alpha-pinene, and fenchone in enrichment cultures depended on the presence of living microorganisms and nitrate. In these experiments, the ratios of number of electrons derived from complete substrate oxidation to number of electrons derived from nitrate reduction ranged from 1.2:1 to 2.9:1. Microbial degradation was accompanied by the formation of small traces of monoterpenes, which were characterized by gas chromatography-mass spectroscopy. The formation of geraniol and geranial from linalool suggested that a 3,1-hydroxyl-delta 1-delta 2-mutase reaction initiates linalool degradation. Seven strains of motile, oval to rod-shaped, facultatively denitrifying bacteria were isolated on agar bottle plates by using linalool, menthol, menth-1-ene, alpha-phellandrene, 2-carene, eucalyptol, and alpha-pinene as sole carbon and energy sources.
Development of a gene reporter system in moderately halophilic bacteria by employing the ice nucleation gene of Pseudomonas syringae
Authors: Arvanitis N , Vargas C , Tegos G , Perysinakis A , Nieto J J , Ventosa A , Drainas C
Published: January 2020

The expression of the ice nucleation gene inaZ of Pseudomonas syringae in several moderate halophiles was investigated to establish its utility as a reporter for promoter activity and gene expression studies in these biotechnologically and environmentally important bacteria. A promoterless version of inaZ was introduced in two different restriction sites and at both orientations in a recombinant plasmid able to replicate in moderate halophiles and, in particular, within the sequence of its pHE1 part, a native plasmid of Halomonas elongata. One orientation of both recombinant constructs expressed high levels of ice nucleation activity in H. elongata and Volcaniella eurihalina cells, indicating that inaZ was probably introduced in the correct orientation downstream of putative native promoters. A recombinant construct carrying a tandem duplication of inaZ at the same orientation gave significantly higher ice nucleation activity, showing that inaZ is appropriate for gene dosage studies. The ice nucleation gene was also expressed in H. elongata and V. eurihalina under the control of Pbla (the promoter of the beta-lactamase gene of Escherichia coli) and Ppdc (the promoter of the pyruvate decarboxylase gene of Zymomonas mobilis). One of the inaZ reporter plasmids expressing high levels of ice nucleation activity under the control of a native putative promoter was also transferred in Halomonas subglaciescola, Halomonas meridiana, Halomonas halodurans, and Deleya halophila. In all cases, Ice+ transconjugants were successfully isolated, demonstrating that inaZ is expressed in a wide spectrum of moderately halophilic species.
Quantification of fungal hyphae in leaves of deciduous trees by automated image analysis
Authors: Daniel O , Schonholzer F , Zeyer J
Published: January 2020

An optical method to quantify the fungal hyphae within decomposing leaves of deciduous trees was developed. The plant matrix was partially destroyed under hydrolytic conditions, and fungal hyphae and cellulose residues within the leaves were stained with Calcofluor M2R. Cellulose residues were subsequently depolymerized by cellulase, and fungal hyphae were separated from the remaining plant matrix with a pressurized air-water mixture. An image analysis program to quantify the fungal hyphae was written. The program included the recognition of fungal hyphae, the elimination of stomata from the images, and the measuring of lengths of fungal hyphae. The optical method was verified by a chemical method relying on glucosamine as an indicator of fungal biomass. The fungal biomass in leaves of Fagus silvatica and Quercus petraea at early states of decomposition was 0.2 to 0.4% of the leaf weight. The biomass reached a maximum within 2 to 4 weeks (optical method, 0.5 to 0.7%; chemical method, 1 to 1.4% of the initial leaf weight) and decreased thereafter.
Genotyping male-specific RNA coliphages by hybridization with oligonucleotide probes
Authors: Hsu F C , Shieh Y S , van Duin J , Beekwilder M J , Sobsey M D
Published: January 2020

F-specific (F+) RNA coliphages are prevalent in sewage and other fecal wastes of humans and animals. There are four antigenically distinct serogroups of F+ RNA coliphages, and those predominating in humans (groups II and III) differ from those predominating in animals (groups I and IV). Hence, it may be possible to distinguish between human and animal wastes by serotyping F+ RNA coliphage isolates. Because serotyping is laborious and requires scarce antiserum reagents, we investigated genotyping using synthetic oligonucleotide probes as an alternative approach to distinguishing the four groups of F+ RNA coliphages. Oligoprobes I, II, III, IV, A, and B were selected to detect group I, II, III, IV, I plus II, and III plus IV phages, respectively. Methods for phage transfer from zones of lysis on a host cell lawn to candidate membrane filters and fixation of genomic nucleic acid on the membranes were optimized. The oligoprobes, which were end labeled with digoxigenin, were applied in DNA-RNA hybridization, and hybrids were observed by colorimetric, immunoenzymatic detection. Of 203 isolates of F+ RNA coliphages from environmental samples of water, wastes, and shellfish, 99.5 and 96.6% could be classified into each group by serotyping and genotyping, respectively. Probes A and B correctly identified 100% of the isolates. On the basis of these results, this method for genotyping F+ RNA coliphages appears to be practical and reliable for typing isolates in field samples.
Degradation of Monochlorinated and Nonchlorinated Aromatic Compounds under Iron-Reducing Conditions
Authors: Kazumi J , Haggblom M M , Young L Y
Published: January 2020

The capacity for Fe(sup3+) to serve as an electron acceptor in the microbial degradation of monochlorinated and nonchlorinated aromatic compounds was investigated in anoxic sediment enrichments. The substrates tested included phenol, benzoate, aniline, their respective monochlorinated isomers, o-, m-, and p-cresol, and all six dimethylphenol isomers. Phenol and 2-, 3-, and 4-chlorophenol were utilized by anaerobic microorganisms, with the concomitant reduction of Fe(sup3+) to Fe(sup2+). The amount of Fe(sup2+) produced in the enrichments was 89 to 138% of that expected for the stoichiometric degradation of these substrates to CO(inf2), suggesting complete mineralization at the expense of Fe reduction. Under Fe-reducing conditions, there was initial loss of benzoate and 3-chlorobenzoate but not of 2- or 4-chlorobenzoate. In addition, there was initial microbial utilization of aniline but not of the chloroaniline isomers. There was also initial loss of o-, m-, and p-cresol in our enrichments. None of the dimethylphenol isomers, however, was degraded within 300 days. Furthermore, we tested the capacity of an Fe-reducing, benzoate-grown culture of Geobacter metallireducens GS-15 to utilize monochlorinated benzoates and phenols. G. metallireducens was able to degrade benzoate and phenol but none of their chlorinated isomers, suggesting that the degradation of chlorophenols in our sediment enrichments may be due to novel Fe-reducing organisms that have yet to be isolated.