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[Message from Lyme].

The background to the discovery of Lyme disease teaches a salutary lesson. The symptoms and signs of this disease had been observed by doctors for a century, particularly in the Scandinavian countries, without anybody being able to draw the right conclusions. The first patients were identified in the USA by their relatives or by themselves. Recognition of their plight by the medical profession was chiefly due to the patients' tenacity. We must remember to pay attention to what patients tell us; they may often be right, even when they seem to be wrong. Where fact and theory are incompatible, it is theory, not fact, that needs to be amended. In all likelihood, we all from time to time observe disorders in our patients that are inconsistent with established scientific models, but which we nevertheless attempt to squeeze into these models. Such an approach is not uncommon in the history of medicine. The message from Lyme calls for humility and reflexion.

Attitude of Health Personnel↗

Isolation and characterization of a carbendazim-degrading Rhodococcus sp. djl-6.

Bacterium djl-6, capable of degrading carbendazim, was isolated by continuous enrichment culture originating from carbendazim-treated soil. The isolate was identified as Rhodococcus sp. according to its phenotypic features, physiologic and biochemical characteristics, and phylogenetic analysis. The strain could use carbendazim as sole carbon or nitrogen source. It showed a high average degradation rate of 55.56 mg . L(-1) . d(-1) in M9 medium amended with carbendazim. High-pressure liquid chromatography-mass spectrometry (HPLC-MS) analysis showed the presence of 2-aminobenzimidazole, benzimidazole, and an unknown metabolite with molecular ions (M(+)) of m/z 104.8 and 118.5. The degradation in the isolate djl-6 seems to be initiated with the cleavage of the methyl carbemate side chain, resulting in the formation of 2-aminobenzimidazole and benzimidazole. This is the first report of the intermediates benzimidazole and 2-aminobenzimidazole found together in the culture filtrate of pure bacterium.

Benzimidazoles↗

Quantification of Gram-negative sulphate-reducing bacteria in rice field soil by 16S rRNA gene-targeted real-time PCR.

For the quantification of Gram-negative sulphate reducers in rice fields, 11 real-time PCR assays were established targeting 16S rRNA genes combined with SybrGreen detection. Three of these assays were specific for the "main" groups, i.e. the Desulfovibrionaceae, the Desulfobacteraceae and Desulfobulbus sp., whereas eight assays were developed for subgroups within the first two main groups. The detection limits of the assays were between 2 x 10(5) and 4 x 10(3) targets g(-1) (wet weight) or less than 0.02% of the eubacterial 16S rDNA targets in bulk soil, rhizosphere soil and rice root DNA extracts. Analysis of soil spiked with defined cell numbers of sulphate-reducing bacteria showed good correlation of measured target numbers to amended cells. In rice field bulk and rhizosphere soil, the Desulfobacteraceae were the predominant main group with target numbers of 6.4 x 10(7) (+/-1.0 x 10(7)) and 7.5 x 10(7) (+/-1.7 x 10(7)), respectively. Within this group the Desulforhabdus/Synthrophobacter assemblage and Desulfobacterium sp. were predominant. At the rice roots, the three main groups were abundant in similar numbers (approx. 1.0 x 10(8)) indicating that the relative abundance of the Desulfovibrionaceae and also of Desulfobulbus sp. was increased, relatively to the Desulfobacteraceae. Within the Desulfovibrionaceae the subgroup was predominant that was detected by assay DSV-II. This assay detects many from rice field soil isolated Desulfovibrio-strains and molecular retrieved sequences. Therefore these organisms that were already detected in the rice field environment by isolation and by molecular techniques are indeed best adapted to the conditions provided by the rice roots.

Benzothiazoles↗

Constructed wetlands for mitigation of atrazine-associated agricultural runoff.

Atrazine was amended into constructed wetlands (59-73x14x0.3 m) for the purpose of monitoring transport and fate of the pesticide to obtain information necessary to provide future design parameters for constructed wetlands mitigation of agricultural runoff. Following pesticide amendment, a simulated storm and runoff event equal to three volume additions was imposed on each wetland. Targeted atrazine concentrations were 0 microg/l (unamended control), 73 microg/l, and 147 microg/l. Water, sediment, and plant samples were collected weekly for 35 days from transects longitudinally distributed throughout each wetland and were analyzed for atrazine using gas chromatography. Between 17 and 42% of measured atrazine mass was within the first 30-36 m of wetlands. Atrazine was below detection limits (0.05 microg/kg) in all sediment and plant samples collected throughout the duration of this study. Aqueous half lives ranged from 16 to 48 days. According to these data, conservative buffer travel distances of 100-280 m would be necessary for effective runoff mitigation.

Journal Article↗

Effect of Soil Texture and Soil Sterilization on Susceptibility of Ovipositing Grasshoppers to Beauveria bassiana

The effect of conidial concentration, soil texture, and soil sterilization on the efficacy of Beauveria bassiana against ovipositing grasshoppers (Melanoplus sanguinipes) was investigated in a controlled environment. In the first experiment, mortality of female grasshoppers ovipositing into a sterile loamy-sand soil containing conidia of B. bassiana was measured. The prevalence of mortality increased as the concentration of conidia in soil increased, and a median lethal concentration of 10(4) colony-forming units (CFU) per gram of soil (dry weight) was observed. Conidia (10(2.9) to 10(3) CFU per abdomen) were recovered from the abdomens of grasshoppers ovipositing into sand containing 10(5.5) and 10(6) conidia per gram. Similar numbers of eggs were laid among treatments during the first oviposition period (1 to 7 days), but an effect of conidial concentration on eggs laid was observed during the second oviposition period (8 to 14 days). This was attributed to reduction in female numbers and not to reduction in fecundity independent of mortality. In a second experiment, grasshoppers oviposited into soils of three different textures (loamy-sand, sandy-loam, or clay-loam) that were amended with 10(5) B. bassiana conidia per gram and possessed either a viable or heat-killed microflora. There was no effect of soil texture on mortality of ovipositing grasshoppers, on the number of eggs laid, on positioning of egg pods in the soil profile, or on numbers of B. bassiana CFU recovered from female abdomens. However, a higher prevalence of mortality was observed for females ovipositing into the sterilized than nonsterilized sandy-loam and clay-loam soils. Substantial populations of fungi and bacteria were recovered from nonsterilized soils. The predominant fungi isolated from these soils were members of the genera Chrysosporium, Fusarium, Gliocladium, Penicillium, Rhizopus, and Trichoderma, whereas Bacillus, Paenibacillus, and Pseudomonas species were the most commonly isolated bacteria. This study demonstrates that ovipositing grasshoppers are susceptible to relatively low densities of conidia in soils of varying textures, but the soil microflora may have an adverse affect on the efficacy of B. bassiana in field soils. Copyright 1998 Academic Press. Copyright 1998 Academic Press

Journal Article↗

Biodegradation of atrazine in surface soils and subsurface sediments collected from an agricultural research farm.

The purpose of the present study was to assess atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) mineralization by indigenous microbial communities and to investigate constraints associated with atrazine biodegradation in environmental samples collected from surface soil and subsurface zones at an agricultural site in Ohio. Atrazine mineralization in soil and sediment samples was monitored as 14CO2 evolution in biometers which were amended with 14C-labeled atrazine. Variables of interest were the position of the label ([U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine), incubation temperature (25 degrees C and 10 degrees C), inoculation with a previously characterized atrazine-mineralizing bacterial isolate (M91-3), and the effect of sterilization prior to inoculation. In uninoculated biometers, mineralization rate constants declined with increasing sample depth. First-order mineralization rate constants were somewhat lower for [2-14C-ethyl]-atrazine when compared to those of [U-14C-ring]-atrazine. Moreover, the total amount of 14CO2 released was less with [2-14C-ethyl]-atrazine. Mineralization at 10 degrees C was slow and linear. In inoculated biometers, less 14CO2 was released in [2-14C-ethyl]-atrazine experiments as compared with [U-14C-ring]-atrazine probably as a result of assimilatory incorporation of 14C into biomass. The mineralization rate constants (k) and overall extents of mineralization (Pmax) were higher in biometers that were not sterilized prior to inoculation, suggesting that the native microbial populations in the sediments were contributing to the overall release of 14CO2 from [U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine. A positive correlation between k and aqueous phase atrazine concentrations (Ceq) in the biometers was observed at 25 degrees C, suggesting that sorption of atrazine influenced mineralization rates. The sorption effect on atrazine mineralization was greatly diminished at 10 degrees C. It was concluded that sorption can limit biodegradation rates of weakly-sorbing solutes at high solid-to-solution ratios and at ambient surface temperatures if an active degrading population is present. Under vadose zone and subsurface aquifer conditions, however, low temperatures and the lack of degrading organisms are likely to be primary factors limiting the biodegradation of atrazine.

Adsorption↗

Fluorescent pseudomonads occurring in Macrotermes subhyalinus mound structures decrease Cd toxicity and improve its accumulation in sorghum plants.

Cd-tolerant bacterial strains of fluorescent pseudomonads, mostly belonging to Pseudomonas monteillii, were isolated from termite mound soil (Macrotermes subhyalinus, a litter-forager and fungus-growing termite), in a Sudanese shrubby savanna, Burkina Faso. Such large mounds appeared as sites of great bacterial diversity and could be considered as hot spots of metal-tolerant fluorescent pseudomonads. Microbial isolates were inoculated to Sorghum plants (S. bicolor) in glasshouse experiments with soil amended with CdCl(2) (560 mg Cd kg(-1) soil). Microbial functional diversity was assessed at the end of the experiment by measurement of in situ patterns of catabolic potentials. All the bacteria isolates significantly improved the shoot and total biomass of sorghum plants compared to the control. Results concerning root biomass were not significant with some strains. Arbuscular mycorrhiza (AM) was greatly reduced by CdCl(2) amendment, and fluorescent pseudomonad inoculation significantly increased AM colonisation in the contaminated soil. The bacterial inoculation significantly improved Cd uptake by sorghum plants. Measurement of catabolic potentials on 16 substrates showed that the microbial communities were different according to the soil amendment. Soils samples inoculated with pseudomonad strains presented a higher use of ketoglutaric and hydroxybutiric acids, as opposed to fumaric acid in soil samples not inoculated. It is suggested that fluorescent pseudomonads could act indirectly in such metabolic processes by involving a lower rate of degradation of citric acid, in line with the effect of small organic acid on phytoextraction of heavy metals from soil. This is a first contribution to bioremediation of metal-contaminated sites with soil-to-plant transfer, using termite built structures. Further data are required on the efficiency of the bacterial strains isolated and on the processes involved.

Animals↗

Comparative evaluation of a bioluminescent bacterial assay in terrestrial ecotoxicity testing.

Despite the widespread and successful use of luminescence-based bioassays in water testing, their applications to soils and sediments is less proven. In part this is because such bioassays have mainly been carried out in an aqueous-based medium and, as such, favour contaminants that are readily water-soluble. In this study, aqueous solutions and soils contaminated with heavy metals (HM), polar organic contaminants and hydrophobic organic contaminants (HOCs) were tested using a range of luminescence-based bioassays (Vibrio fischeri, Escherichia coli HB101 pUCD607 and Pseudomonas fluorescens 10586r pUCD607). For the first two chemical groups, the assays were highly reproducible when optimised extraction procedures were employed but for HOCs the bioassay response was poor. Quantitative structure-activity relationships (QSARs) obtained from aqueous solutions had a linear response although correlation for the chemicals tested using bacterial bioassays was significantly less sensitive than that of sublethal tests for Tetrahymena pyriformis. Bacterial and Dendrobaena veneta bioassay responses to extracts from HM amended soils showed that a clear relationship between trophic levels could be obtained. There is no doubt that the wide range of bioluminescent-based bioassays offers complementary applications to traditional testing techniques but there is a significant need to justify and optimise the extraction protocol prior to application.

Aliivibrio fischeri↗

A taxonomic revision of the small catarrhine primates from the early Miocene of East Africa.

This paper presents a detailed systematic revision of the small catarrhine primates from the early Miocene of East Africa, recovered from sites in Western Kenya and in Uganda dated at between 22 and 17 m.y. Revised diagnoses and amended hypodigms for each of the species are presented. In addition to the currently identified taxa, Limnopithecus legetet Hopwood, 1933, Dendropithecus macinnesi (Le Gros Clark and Leakey, 1950) and Micropithecus clarki Fleagle and Simons, 1978, two further species are recognized. Limnopithecus evansi (MacInnes, 1943) is resurrected as a valid species, based primarily on previously described material from Songhor, and a new genus, Kalepithecus, is described here for the first time, in order to accommodate distinctive material from Songhor and Koru. The distribution of each species in time and space, and the phylogenetic relationships, are discussed in the light of this taxonomic revision.

Africa, Eastern↗

Simultaneous determination of losartan, EXP-3174 and hydrochlorothiazide in plasma via fully automated 96-well-format-based solid-phase extraction and liquid chromatography-negative electrospray tandem mass spectrometry.

An automated, sensitive and high-throughput liquid chromatographic/electrospray tandem mass spectrometric (LC-MS/MS) assay was developed for the simultaneous determination of losartan (LOS), its major circulating metabolite EXP-3174 and hydrochlorothiazide (HCTZ) in human plasma. LOS and HCTZ coexist in the same drug formulation, and this is the first method that enables the simultaneous determination of both drugs along with the active metabolite of LOS. Since these drugs have different physicochemical properties, the employment of a liquid-liquid extraction (LLE) protocol was precluded. A fully automated solid-phase extraction (SPE) protocol, based on 96-well format plates, was used to isolate these compounds and furosemide (internal standard, IS) from plasma. Washing and elution steps were amended accordingly in order to minimize any matrix effect from components of the plasma without reducing the elution of the molecules of interest. The compounds were eluted from a C18 column and detected with an API 3000 triple-quadrupole mass spectrometer using negative electrospray ionization and multiple reaction monitoring (MRM). The assay was linear over the range 1.00-400 ng/mL for LOS and EXP-3174 and 0.500-200 ng/mL for HCTZ, respectively, when 200 microl of plasma was used in the extraction. The overall intra- and interassay variations were within acceptance limits. The analysis time for each sample was 4 min, and more than 300 samples could be analyzed in one day by running the system overnight. The assay was simple, highly sensitive, selective, precise, fast, and it enables the reliable determination of LOS, EXP-3174 and HCTZ in pharmacokinetic or bioequivalence studies after per os administration of a single tablet containing both drugs.

Antihypertensive Agents↗

Intentional and unintentional abuse of infants and children.

Intentional abuse of an infant is usually apparent. External injuries such as burns, bites, and bruises, as well as the skeletal changes of fractures, frequently multiple and in various stages of healing, are obviously intentionally inflicted, and are impossible accidental injuries for the nonambulatory young infant. Similar injuries in young children may be more difficult to evaluate because of their fear of and intimidation by the person who inflicted the injury. Fortunately, the high degree of suspicion regarding the nature of the injury permits the physician to make his accusations with legal protection in our judicial system. Every radiologist should be concerned with the responsibility of reporting to the referring physician the possibility of intentional trauma to infants and children. In Harris County, where Houston is located, there are 1,500 reports per month of child abuse; in other words, this approximates 18,000 cases a year in our community, and the radiologist is frequently the first physician to see evidence of the abused child. Not only is it a moral responsibility for the radiologist to report his suspicions, but in the state of Texas, as in other states, "any person having cause to believe that a child's physical and mental health, or welfare has been or may be adversely affected by abuse or neglect shall report" to the appropriate agency. A more recent amendment to this law is a penalty for failure to report. A person commits an offense if the person has cause to believe that a child's physical and mental health or welfare has been or may be adversely affected further by abuse or neglect and knowingly fails to report it. It is hoped that any radiologist recognizing either pathognomonic or suspicious signs of child abuse will have the conscience and courage to take a strong stand for the protection of the abused infant or child. Accidental injuries in older children may offer problems in diagnosis if there is no history available or if there is a denial of an injury. Some of these injuries may produce radiographic findings suggesting some form of metaphyseal or diaphyseal dysplasia. Iatrogenic injuries are frequently the result of physiologic or anatomical response to proper and lifesaving treatment. The most serious of these are found in the premature infant, who may suffer chronic lung disease or, more seriously, brain damage.(ABSTRACT TRUNCATED AT 400 WORDS)

Bone Diseases, Developmental↗

Effect of organic matter decomposition level on bacterial species diversity and composition in relationship to pythium damping-off severity.

Rhizosphere bacteria were isolated from root tip segments of cucumber seedlings grown in a suppressive, slightly decomposed light-colored peat mix, a conducive, more decomposed dark-colored peat mix, and a suppressive dark peat mix amended with composted hardwood bark. The bacteria were identified by a gas chromatographic fatty acid methyl ester analysis. The total number of taxa recovered from a single root tip segment ranged from 9 to 18. No single taxon predominated on all root tip segments harvested from any of the mixes. The highest relative population density reached by a given taxon on any root tip segment was 45%. Hill's first and second diversity numbers, the modified Hill's ratio, and Hurlbert's rarefaction method, which were used as measures of species diversity, indicated that the organic matter decomposition level of the potting mixes did not affect bacterial species diversity. Bray-Curtis polar ordination and Dice resemblance functions, however, indicated that the organic matter decomposition level of a mix significantly influenced the composition of bacterial species in the rhizosphere. Pseudomonas spp. and other taxa capable of inducing suppression of pythium damping-off predominated in the suppressive mixes. These organisms were absent from the conducive mix, in which Arthrobacter and Bacillus spp. predominated. Although effective bacterial biocontrol agents were isolated from both the suppressive mixes and the conducive mix, the majority were isolated from the less decomposed suppressive mixes. Finally, the efficacy of strains was significantly greater in the slightly decomposed light peat mix than in the decomposed dark peat mix. Natural disease suppression within these mixes was associated with the organic matter decomposition level and the bacterial species compositions of the mixes.

Journal Article↗

Effects of some salts and sodicity on the growth of a Rhizobium leguminosarum bv. viceae strain isolated from a salt-affected soil.

The effects of sodium (Na+), calcium (Ca2+), magnesium (Mg2+), and boron (B) concentrations and sodicity, as measured by the sodium adsorption ratio (SAR), on the growth of a Rhizobium leguminosarum bv. viceae strain isolated from a salt-affected soil were studied. The rate of growth was measured in a yeast extract-mannitol broth, amended with salts having electrical conductivity (EC) of 4, 8, and 16 dS x m(-1). Each salinity level was prepared to achieve SAR values of 10, 20, and 30 with or without graded B concentrations of 0.5, 1, 3, and 5 mg x L(-1). We found that salinity levels equal to or more than 8 dS x m(-1) had negative effects on Rhizobium growth during the first days of incubation, but the effects became less pronounced after 1 week. Na+ concentrations of more than 1.1 g x L(-1) retarded growth, especially at high SAR values (i.e., at low Ca2+ concentrations). The retardation of growth increased with increases in EC up to 16 dS x m(-1), at all sodicity levels. Mg2+ added together with Na+ or with Ca2+ + Na+ affected growth more negatively than Ca2+ + Na+ alone. The effect of Mg2+ became more pronounced with increased salinities and sodicities. It was concluded that EC of more than 4 dS x m(-1) retarded growth of Rhizobium, but only at high sodicity levels. The relative specific ion effect on growth was in the order Na+ < Ca2+ < Mg2+. The harmful effect of Mg2+ on this strain was accentuated by adding Ca2+ to the cultural medium. When SAR increased from 10 to 30, Na+ had no clear effect on growth, irrespective of the accompanied cations, i.e, Ca2+, Mg2+, or Ca2+ + Mg2+. Growth was reduced by B concentrations as low as 0.5 mg x L(-1), and the B effect was enhanced by increased salinity.

Boron↗

Viral proteases: an emerging therapeutic target.

Only a few viral diseases are presently treatable because of our limited knowledge of specific viral target molecules. An attractive class of viral molecules toward which chemotherapeutic agents could be aimed are proteases coded by some virus groups such as retro- or picornaviruses (poliomyelitis, common cold virus). The picornavirus enzymes were discovered first, and they have now been characterized by a combination of molecular-genetic and biochemical approaches. Several laboratories have expressed the picornaviral enzymes in heterologous systems and have reported proteolytic activity, as well as the high cleavage fidelity diagnostic of the viral proteases. After dealing with several technical difficulties often encountered in standard genetic engineering approaches, one viral protease is now available to us in quantity and is amendable to mutagenic procedures. The initial outcome of the mutagenesis studies has been the confirmation of our earlier work with inhibitors, which suggested a cysteine active-site class. There is a clustering of active-site residues which may be unique to these viruses. The requirement for an active-site cysteine-histidine pair in combination with detailed information on the viral cleavage sites has permitted design of selective inhibitors with attractive antiviral properties. Future goals include investigation of the structural basis for selective processing and application of the cleavage specificity to general problems in genetic engineering.

Humans↗

Effects of organic acids on copper and cadmium desorption from contaminated soils.

A study was conducted to investigate the effect of organic acids on Cd and Cu desorption from natural contaminated soils (NCS) with permanent contamination by metal smelters and from artificial contaminated soils (ACS) derived from an artificial amendment of Cd to three representative zonal soils in Central China. Results showed that the desorption of Cd in either NCS or ACS, with the increment of tartrate or citrate concentration in desorption solution, can be characterized as a valley-like curve. The presence of tartrate or citrate at a low concentration (< or =0.5 mmol/l) inhibited Cd desorption from these two types of soils, whereas the presence of organic acids at high concentrations (> or =2 mmol/l for citrate and about > or =15 mmol/l for tartrate) apparently promoted Cd desorption. The desorption curve of Cu by tartrate solution with different tartrate concentrations can also be characterized as a valley-like curve, while the desorption of Cu in the presence of citrate was directly enhanced with the increment of citrate concentration. With the enhancement of initial pH value from 2 to 8 in the presence of citrate, Cu desorption ratio decreased at the first stage, then increased, and then decreased again. A valley and a peak sequentially appeared in the Cd or Cu desorption curve with initial pH value increment. Compared with citrate, the desorption ratio of Cd or Cu from NCS or ACS was directly decreased in the presence of tartrate, with the enhancement of the pH value from 2 to 8. Cd or Cu desorption was clearly enhanced when the electrolyte concentration of KNO3 or KCl increased in the presence of 2 mmol/l tartrate. Moreover, a higher desorption ratio of Cd or Cu was shown with KCl electrolyte than with KNO3 electrolyte with the same concentration. Based on these observations, we suggest that bioavailabilities of heavy metal can be promoted with selected suitable types and concentrations of organic acid amendment and reasonable field condition.

Adsorption↗

Are HMO enrollees being attracted by a liberal maternity benefit?

A study of recent birth patterns in the Southern California Region of the Kaiser-Permanente Medical Care Program (KPMCP) suggests that individuals may have been attracted to the Program by a liberal maternity benefit. The attraction is reflected in both the type of members joining KPMCP and the birth rate of those members. Although the KPMCP birth rate has been below that of the general population, new members in their first year of coverage delivered approximatey one third of all KPMCP births in 1977, twice the number of births that would be anticipated from an equal number of members in the plan for one year or more. The maternity copayment of up to $350 did not deter women already pregnant from joining KPMCP. Termination rates for new members who gave birth, however, were no higher than expected. The Pregnancy Disability Amendment of Title VII of the Civil Rights Act of 1964, which became effective April 29, 1979, may alter the maternity benefits offered by alternative insurance carriers. The law could impact KPMCP's enrollment and utilization of obstetric services.

Adolescent↗