Transcriptome Analysis of Aspergillus flavus Reveals veA-Dependent Regulation of Secondary Metabolite Gene Clusters, Including the Novel Aflavarin Cluster.

The global regulatory veA gene governs development and secondary metabolism in numerous fungal species, including Aspergillus flavus. This is especially relevant since A. flavus infects crops of agricultural importance worldwide, contaminating them with potent mycotoxins. The most well-known are aflatoxins, which are cytotoxic and carcinogenic polyketide compounds. The production of aflatoxins and the expression of genes implicated in the production of these mycotoxins are veA dependent. The genes responsible for the synthesis of aflatoxins are clustered, a signature common for genes involved in fungal secondary metabolism. Studies of the A. flavus genome revealed many gene clusters possibly connected to the synthesis of secondary metabolites. Many of these metabolites are still unknown, or the association between a known metabolite and a particular gene cluster has not yet been established. In the present transcriptome study, we show that veA is necessary for the expression of a large number of genes. Twenty-eight out of the predicted 56 secondary metabolite gene clusters include at least one gene that is differentially expressed depending on presence or absence of veA. One of the clusters under the influence of veA is cluster 39. The absence of veA results in a downregulation of the five genes found within this cluster. Interestingly, our results indicate that the cluster is expressed mainly in sclerotia. Chemical analysis of sclerotial extracts revealed that cluster 39 is responsible for the production of aflavarin.

A strong response to selection on mass-independent maximal metabolic rate without a correlated response in basal metabolic rate.

Metabolic rates are correlated with many aspects of ecology, but how selection on different aspects of metabolic rates affects their mutual evolution is poorly understood. Using laboratory mice, we artificially selected for high maximal mass-independent metabolic rate (MMR) without direct selection on mass-independent basal metabolic rate (BMR). Then we tested for responses to selection in MMR and correlated responses to selection in BMR. In other lines, we antagonistically selected for mice with a combination of high mass-independent MMR and low mass-independent BMR. All selection protocols and data analyses included body mass as a covariate, so effects of selection on the metabolic rates are mass adjusted (that is, independent of effects of body mass). The selection lasted eight generations. Compared with controls, MMR was significantly higher (11.2%) in lines selected for increased MMR, and BMR was slightly, but not significantly, higher (2.5%). Compared with controls, MMR was significantly higher (5.3%) in antagonistically selected lines, and BMR was slightly, but not significantly, lower (4.2%). Analysis of breeding values revealed no positive genetic trend for elevated BMR in high-MMR lines. A weak positive genetic correlation was detected between MMR and BMR. That weak positive genetic correlation supports the aerobic capacity model for the evolution of endothermy in the sense that it fails to falsify a key model assumption. Overall, the results suggest that at least in these mice there is significant capacity for independent evolution of metabolic traits. Whether that is true in the ancestral animals that evolved endothermy remains an important but unanswered question.

Cumulative incidence rate of medical consultation for fecundity problems--analysis of a prevalent cohort using competing risks.

STUDY QUESTION: What is the incidence of medical consultation for fecundity problems in the French population, taking into account pregnancy occurrence and resumption of contraceptive use?. SUMMARY ANSWER: Considering the occurrence of a pregnancy and resumption of use of contraception as competing risks, the cumulative incidence rate of medical consultation for fecundity problems was 9.0% [95% confidence interval (CI): 6.5%; 11.9%] after 12 months of unprotected intercourse and 12.2% [95% CI: 9.6%; 15.3%] after 24 months. WHAT IS KNOWN ALREADY: Estimates of the prevalence of medical consultation due to involuntary infertility among couples who have sought a pregnancy for more than 12 months range from 25 to 50%. Most of the studies however are limited by retrospective data collection, without considering the duration of time since the beginning of the period of unprotected intercourse (PUI) and without considering medical consultation for fecundity problems as a competing risk. STUDY DESIGN, SIZE, DURATION: This study is based on the Observatory of Fecundity in France survey, a population-based probability survey designed to estimate the frequency of involuntary infertility on a nationwide basis and to explore the associations with environmental factors. Women answered two telephone questionnaires, the first at the time of enrolment in 2007, the second at follow-up 1 year later. The current analysis was performed among a subsample of 6577 women recruited before or during a PUI and followed-up for 1 year. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study sample comprised 940 women aged 18-44 years who had a PUI between the time of enrolment and the 1-year follow-up, and who had not consulted a physician for fecundity problems for the current PUI prior to enrolment. Women reported all the medical consultations they had because of difficulties becoming pregnant during the current PUI. The date of each consultation was carefully assessed. In France, women can consult a gynaecologist directly without referral by their general practitioner. The occurrence of a pregnancy and resumption of contraceptive use were considered as informative censoring events, using a competing risk model. MAIN RESULTS AND THE ROLE OF CHANCE: Using the competing risk survival model, the cumulative incidence rate of first consultation was 9.0% [95% CI: 6.5%; 11.9%] 12 months after the start of the PUI and 12.2% [95% CI: 9.6%; 15.3%] after 24 months. The Kaplan-Meier method, which does not take competing risks into account, yielded substantially higher estimates: 26.0% [95% CI: 18.8%; 32.5%] at 12 months and 56.8% [95% CI: 44.2%; 66.6%] at 24 months. Among the 219 women who had attempted to become pregnant for at least 12 months, cumulative incidences of first medical consultations were 28.2% [18.7-38.9%] 24 months after the start of the PUI, and 31.2% [21.3- 42.4%] after 36 months. The rates were higher among nulliparous but non-nulligravid women, followed by nulligravid women, as compared with parous women. Age was not strongly related to the occurrence of medical consultation. LIMITATIONS, REASONS FOR CAUTION: The main limitation of this study is the number of women lost to follow-up (29.7%). In addition, results regarding the absence of an age effect should be taken with caution as few women in our study were aged over 35 years. Although such an attrition rate is commonly observed in prospective studies in the general population, it could have induced a selection bias that may have led to an underestimation of the rates of medical consultation. Sensitivity analyses, using the inverse probability weighting method suggest that our results are unlikely to be biased. WIDER IMPLICATIONS OF THE FINDINGS: This study reveals frequencies of medical consultation for fertility problems, which, after considering competing events such as pregnancy in a relevant statistical model, are lower than generally reported in the literature. The results also indicate the existence of a difference between the potential need and the actual use of medical care for fecundity problems. This suggests a need for studies to look for factors other than medical recommendations that may play a role in the patterns of medical seeking behaviours for fecundity problems, such as women's reproductive history, socio-economic characteristics or accessibility to infertility services. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by grants from ANR (French Agency for Research, SEST call on Environmental and Occupational Health), ANSES (French Agency for Food, environmental and Occupational Health Safety, EST call on Environmental and Occupational Health), InVS (French Institute for Public Health Surveillance). The team of Environmental Epidemiology applied to Fecundity and Reproduction has been funded by an AVENIR grant from Inserm (2007). Authors declare no conflict of interest.

Estimating motor unit numbers from a CMAP scan: Repeatability study on three muscles at 15 centres.

OBJECTIVE: To assess the repeatability and suitability for multicentre studies of MScanFit motor unit number estimation (MUNE), which involves modelling compound muscle action potential (CMAP) scans. METHODS: Fifteen groups in 9 countries recorded CMAP scans twice, 1-2 weeks apart in healthy subjects from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. The original MScanFit program (MScanFit-1) was compared with a revised version (MScanFit-2), designed to accommodate different muscles and recording conditions by setting the minimal motor unit size as a function of maximum CMAP. RESULTS: Complete sets of 6 recordings were obtained from 148 subjects. CMAP amplitudes differed significantly between centres for all muscles, and the same was true for MScanFit-1 MUNE. With MScanFit-2, MUNE differed less between centres but remained significantly different for APB. Coefficients of variation between repeats were 18.0% for ADM, 16.8% for APB, and 12.1% for TA. CONCLUSIONS: It is recommended for multicentre studies to use MScanFit-2 for analysis. TA provided the least variable MUNE values between subjects and the most repeatable within subjects. SIGNIFICANCE: MScanFit was primarily devised to model the discontinuities in CMAP scans in patients and is less suitable for healthy subjects with smooth scans.

Estimation of the frequency of involuntary infertility on a nation-wide basis.

BACKGROUND: Assessing couple fecundity on a nation-wide basis without excluding couples who eventually remain infertile is challenging. Our aim was to describe couple fecundity (in terms of frequency of involuntary infertility) among the general population living in France. METHODS: We used a current-duration design. A random sample of 64 262 households was selected in 2007-2008, allowing us to identify 15 810 women aged 18-44 years. Eligible women (n= 1089) were those having regular sexual intercourse with a male partner, not using any method of contraception and not having delivered in the previous 3 months. These women reported information on the current duration of unprotected intercourse (CDUI, the time elapsed between the start of the period of unprotected intercourse and the time of inclusion in the study). The CDUI distribution was used to estimate the frequency of involuntary infertility, using a newly developed statistical technique that does not require couples to be followed up until the end of the period of unprotected intercourse. RESULTS: CDUI was defined for 867 women. An estimated 46% of couples had no detected pregnancy conceived during the first 6 months of unprotected intercourse [95% confidence interval (CI), 36-56%]. The proportions of couples with no detected pregnancy within 12 and 24 months were 24% (19-30%) and 11% (8-14%), respectively. CONCLUSIONS: These results constitute one of the few descriptions of the fecundity of a nation-wide representative sample of couples from the general population, not limited to couples who eventually conceived or to those resorting to medical help.

Effects of buprenorphine on acute pain and inflammation in the adjuvant-induced monoarthritis rat model.

Background and aim: Animal modelling of arthritis is often associated with pain and suffering. Severity may be reduced with the use of analgesia which is, however, often withheld due to concerns of introducing a confounding variable. It is therefore important to design and validate pain relief protocols that reduce pain without compromising the scientific objectives. The present study evaluated the effect of buprenorphine analgesia in the immediate post-induction period of an adjuvant-induced monoarthritic rat model. The aim of this study was to extend previous work on refinement of the model by alleviating unnecessary pain. Methods: Male and female Sprague Dawley rats were injected with 20 µl of complete Freund's adjuvant (CFA) into the left ankle. Rats were treated with buprenorphine, either injected subcutaneously or ingested voluntarily, and were compared to rats given subcutaneous injections with vehicle (saline or pure nut paste) or carprofen the first three days post CFA-injection. Measurements of welfare, clinical model-specific parameters and pain-related behaviour were assessed. Results: Buprenorphine, administered either subcutaneously (0.10 or 0.15 mg/kg, twice daily) or by voluntary ingestion in nut paste (1.0 or 3.0 mg/kg, twice daily), improved mobility, stance, rearing and lameness scores significantly 7 h post CFA-injection. Mechanical hyperalgesia peaked at 7 h and was significantly lower in buprenorphine-treated animals, compared to vehicle-treated animals. Joint circumference was highest 24-72 h after CFA injection. Animals treated with buprenorphine did not decrease in joint circumference, opposite carprofen treated animals. Conclusion: Buprenorphine, administered either subcutaneously or by voluntary ingestion, provides adequate analgesia for both sexes within the first 24 h post CFA-injection. Buprenorphine treatment improved clinical scores and appeared not to suppress the inflammatory response. The present study supports previous findings that voluntarily ingested buprenorphine is an effective alternative to repeated injections.

[Prevalence of asthma and associated risk factors in schoolchildren from an area of indigenous population]. / Prevalencia de asma y factores de riesgo asociados en escolares provenientes de una zona de pueblos indígenas.

INTRODUCTION: The prevalence of asthma in Chile ranges from 10.2 to 14.9%. In previous studies, the Araucanía Region has not been included. OBJECTIVE: To determine the prevalence of asthma in the school po pulation of the Araucanía Region. SUBJECTS AND METHOD: The ISAAC questionnaires were used for asthma symptoms in addition to a questionnaire for recording sociodemographic data, belonging to the Mapuche ethnicity, type of heating, exposure to indoor air pollution, and family history. The Binomial Regression Model was used to evaluate the effect of each of the different variables of inter est, adjusting by age groups (6-7 and 13-14 years). The model also evaluated the additive interaction between these variables and age. RESULTS: 823 surveys were applied, where the prevalence of asthma was 14.2% and 23.2% in the 6-7 year old group and the 13-14 year old group, respectively. 43.7% de clare to be Mapuche, 32.9% live in rural areas, and 81.4% use firewood as a heating method. Through binomial regression model analysis, where for the study group, living in the coastal commune was significantly associated with a lower prevalence of asthma (-13.2% [CI: -17.7 to -8.6]. The history of an asthmatic mother was significantly associated with a higher prevalence of asthma (17.9% [CI: 2.7 to 33.1]. Living in a rural area, to be Mapuche or the type of heating used, showed differences statistically significant (p 0.18, p 0.609 and p 0.480, respectively) Conclusion: 13-14 year-olds school children in the Araucanía Region presented a higher prevalence of asthma. There was an association with asthma in the mother where this increase is not associated with living in a rural area, to be Ma puche or type of heating.

GSEVM v.2: MCMC software to analyze genetically structured environmental variance models.

This note provides a description of software that allows to fit Bayesian genetically structured variance models using Markov chain Monte Carlo (MCMC). The gsevm v.2 program was written in Fortran 90. The DOS and Unix executable programs, the user's guide, and some example files are freely available for research purposes at http://www.bdporc.irta.es/estudis.jsp. The main feature of the program is to compute Monte Carlo estimates of marginal posterior distributions of parameters of interest. The program is quite flexible, allowing the user to fit a variety of linear models at the level of the mean and the logvariance.

Identifiability of parameters and behaviour of MCMC chains: a case study using the reaction norm model.

Markov chain Monte Carlo (MCMC) enables fitting complex hierarchical models that may adequately reflect the process of data generation. Some of these models may contain more parameters than can be uniquely inferred from the distribution of the data, causing non-identifiability. The reaction norm model with unknown covariates (RNUC) is a model in which unknown environmental effects can be inferred jointly with the remaining parameters. The problem of identifiability of parameters at the level of the likelihood and the associated behaviour of MCMC chains were discussed using the RNUC as an example. It was shown theoretically that when environmental effects (covariates) are considered as random effects, estimable functions of the fixed effects, (co)variance components and genetic effects are identifiable as well as the environmental effects. When the environmental effects are treated as fixed and there are other fixed factors in the model, the contrasts involving environmental effects, the variance of environmental sensitivities (genetic slopes) and the residual variance are the only identifiable parameters. These different identifiability scenarios were generated by changing the formulation of the model and the structure of the data and the models were then implemented via MCMC. The output of MCMC sampling schemes was interpreted in the light of the theoretical findings. The erratic behaviour of the MCMC chains was shown to be associated with identifiability problems in the likelihood, despite propriety of posterior distributions, achieved by arbitrarily chosen uniform (bounded) priors. In some cases, very long chains were needed before the pattern of behaviour of the chain may signal the existence of problems. The paper serves as a warning concerning the implementation of complex models where identifiability problems can be difficult to detect a priori. We conclude that it would be good practice to experiment with a proposed model and to understand its features before embarking on a full MCMC implementation.

Acute neurological problems: frequency, consultation patterns and the uses of a rapid access neurology clinic.

In secondary care, some patients with acute neurological symptoms are never seen by a neurologist. Rapid access neurology clinics could provide patients with timely access to neurology services. We analysed a retrospective cohort of 12,024 consecutive patients attending the 'immediate care' area of the emergency department or the acute medical admissions unit of the Royal Infirmary of Edinburgh. A total of 1,036 patients (9%) presented with a neurological complaint, of whom 680 (66%) did not have any contact with neurology services. The most common problems were epileptic seizure, cerebrovascular diseases and headache. Of the patients with epileptic seizure or headache who were not seen by a neurologist, about 40% might have benefited from neurological assessment. Following the introduction of a weekly rapid access neurology clinic, the most common problems seen were headache, symptoms that turned out to be medically unexplained and epileptic seizure.

Liver Transplant After Normothermic Regional Perfusion From Controlled Donors After Circulatory Death: The Norwegian Experience.

BACKGROUND: In order to meet the increasing demand for donor organs, the concept of donation after circulatory death (DCD) was reintroduced in Norway, first as a pilot study, followed by the use of DCD as institutional practice. We report the current Norwegian experience with liver transplant after DCD. METHODS: After acceptance from next of kin, life support was withdrawn from patients with devastating brain injury and cardiac arrest observed. After a 5-minute "no-touch" period, extracorporeal membrane oxygenation for post mortem normothermic regional perfusion (NRP) by extracorporeal membrane oxygenator circuit was established. Data from all liver transplant recipients receiving controlled DCD (cDCD) livers in Oslo were analyzed. RESULTS: From 2015 to 2017, a total of 8 patients underwent liver transplant with cDCD and NRP liver grafts in Norway. Median Model for End-Stage Liver Disease score was 26 (range, 6-40). There were no cases of delayed graft function or graft loss. Seven patients have reached 1 year of follow-up, and 1 patient has reached 6 months. Two patients have recurrence of primary disease (primary sclerosing cholangitis and steatohepatitis). All patients had normalized liver function at last follow-up. Two patients underwent procedures for biliary complications. In 1 patient, leakage from the cystic duct was successfully handled endoscopically by stenting. In the other patient, a suspected stricture on magnetic resonance imaging led to an endoscopic retrograde cholangiopancreatography, which did not confirm signs of biliary stenosis. There was 1 instance of hepatic artery stenosis, which was managed with endovascular technique. CONCLUSION: The results after liver transplant using cDCD with NRP are good. The rate of complications seems to be within the same range as when using conventional donation after brain death grafts.

A nuclease-resistant protein kinase C alpha ribozyme blocks glioma cell growth.

We investigated the cleavage activity, stability, and efficacy of 2'-amino pyrimidine modified ribozymes on malignant glioma growth. A synthetic protein kinase C alpha (PKC alpha) ribozyme with complete pyrimidine nucleotide substitution retained a comparable cleavage activity compared with the unmodified ribozyme. The half-life of the modified ribozyme in serum was increased 14,000-fold compared with the unmodified version. The PKC alpha modified ribozyme inhibited glioma cell growth in vitro as a result of the inhibition of PKC alpha gene expression. A single injection of cationic liposome ribozyme complexes into glioma tumors inhibited tumor growth, demonstrating both the efficacy of the ribozyme and a major role of PKC alpha in tumor growth.

Local endostatin treatment of gliomas administered by microencapsulated producer cells.

We describe a technique for the treatment of malignant brain tumors based on local delivery of the anti-angiogenic protein endostatin from genetically engineered cells encapsulated in ultrapure sodium alginate. Alginate consists of L-guluronic and D-mannuronic acid, which in the presence of divalent cations forms an extended gel network, in which cells reside and remain immunoisolated, when implanted into the rat brain. Here, we show that endostatin-transfected cells encapsulated in alginate maintain endostatin secretion for at least four months after intracerebral implantation in rats. During the implantation period 70% of the encapsulated cells remained viable, as opposed to 85% in in vitro-cultured capsules. Rats that received transplants of BT4C glioma cells, together with endostatin-producing capsules (0.2 microg/ml per capsule), survived 84% longer than the controls. The endostatin released from the capsules led to an induction of apoptosis, hypoxia, and large necrotic avascular areas within 77% of the treated tumors, whereas all the controls were negative. The encapsulation technique may be used for many different cell lines engineered to potentially interfere with the complex microenvironment in which tumor and normal cells reside. The present work may thus provide the basis for new therapeutic approaches toward brain tumors.

Analysis of milk production traits in early lactation using a reaction norm model with unknown covariates.

The reaction norm model is becoming a popular approach to study genotype x environment interaction (GxE), especially when there is a continuum of environmental effects. These effects are typically unknown, and an approximation that is used in the literature is to replace them by the phenotypic means of each environment. It has been shown that this method results in poor inferences and that a more satisfactory alternative is to infer environmental effects jointly with the other parameters of the model. Such a reaction norm model with unknown covariates and heterogeneous residual variances across herds was fitted to milk, protein, and fat yield of first-lactation Danish Holstein cows to investigate the presence of GxE. Data included 188,502 first test-day records from 299 herds and 3,775 herd-years in a time period ranging from 1991 to 2003. Variance components and breeding values were estimated with a Bayesian approach implemented using Markov chain Monte Carlo. The posterior distribution of the variance of genetic slopes was markedly shifted away from zero for all traits under study, supporting the presence of GxE. The ratio of the genetic slope variance to the genetic level variance was highest for fat yield, followed by protein and milk yields. Genetic correlations between environments that differ by plus and minus 1 standard deviation from the mean environmental effect were 0.93, 0.91, and 0.89 for milk, protein, and fat yield, respectively. Genetic variances and heritabilities increased with increasing level of environmental effects. The rank correlations between predicted breeding values at the 5th and 95th percentiles of the distribution of environmental effects were, respectively, equal to 0.91, 0.90, and 0.76, for milk, protein, and fat yield. Thus in this study, although GxE was detected, it has a small effect on reranking of candidates for selection.

The application of random regression models in the genetic analysis of monthly egg production in turkeys and a comparison with alternative longitudinal models.

Random regression models (RR) have become a popular methodology for the genetic study of longitudinal data since the last decade. The first objective of the current study was to investigate the application of RR models for the genetic analysis of egg production in turkeys. Data collected from a heavy dam line were used to estimate genetic parameters with 2 RR models, one having second-order Legendre polynomials as regression over time (RR2) and another with third-order polynomials (RR3). The second objective was to benchmark the performance of RR models with more conventional methods, so genetic parameters were reestimated using a multitrait (MT) and a repeatability model. To assess the model efficiency of predicting missing values, a reduced data set was used, and for each model, the predicted values of the deleted records were compared with the true values. The RR models were further compared against each other by eliminating the last period and estimating the MS error of the predictions for both models. The repeatability model had the poorest performance in predicting missing values. Heritability estimates from RR2 and MT models were close, whereas the RR3 model estimates were different. Both RR models demonstrated better prediction ability than the MT model. However, when RR models were compared solely, the RR2 model resulted in the smallest MS error. The results indicated that the RR3 model overfitted the data, suggesting that the choice of the appropriate polynomial order requires careful consideration. The present study illustrated that the application of RR models for the genetic analysis of egg production in turkeys is not only feasible but also offers a high accuracy of prediction.

Insulin resistance in vascular endothelial cells promotes intestinal tumour formation.

The risk of several cancers, including colorectal cancer, is increased in patients with obesity and type 2 diabetes, conditions characterised by hyperinsulinaemia and insulin resistance. Because hyperinsulinaemia itself is an independent risk factor for cancer development, we examined tissue-specific insulin action in intestinal tumour formation. In vitro, insulin increased proliferation of intestinal tumour epithelial cells by almost two-fold in primary culture of tumour cells from ApcMin/+ mice. Surprisingly, targeted deletion of insulin receptors in intestinal epithelial cells in ApcMin/+ mice did not change intestinal tumour number or size distribution on either a low or high-fat diet. We therefore asked whether cells in the tumour stroma might explain the association between tumour formation and insulin resistance. To this end, we generated ApcMin/+ mice with loss of insulin receptors in vascular endothelial cells. Strikingly, these mice had 42% more intestinal tumours than controls, no change in tumour angiogenesis, but increased expression of vascular cell adhesion molecule-1 (VCAM-1) in primary culture of tumour endothelial cells. Insulin decreased VCAM-1 expression and leukocyte adhesion in quiescent tumour endothelial cells with intact insulin receptors and partly prevented increases in VCAM-1 and leukocyte adhesion after treatment with tumour necrosis factor-α. Knockout of insulin receptors in endothelial cells also increased leukocyte adhesion in mesenteric venules and increased the frequency of neutrophils in tumours. We conclude that although insulin is mitogenic for intestinal tumour cells in vitro, impaired insulin action in the tumour microenvironment may be more important in conditions where hyperinsulinaemia is secondary to insulin resistance. Insulin resistance in tumour endothelial cells produces an activated, proinflammatory state that promotes tumorigenesis. Improvement of endothelial dysfunction may reduce colorectal cancer risk in patients with obesity and type 2 diabetes.

Iron and arsenic release from aquifer solids in response to biostimulation.

Biostimulation has been used at various contaminated sites to promote the reductive dechlorination of trichloroethylene (TCE), but the addition of carbon and energy donor also stimulates bacteria that use Fe(III) as the terminal electron acceptor (TEA) in potential competition with dechlorination processes. Microcosm studies were conducted to determine the influence of various carbon donors on the extent of reductive dissolution of aquifer solids containing Fe(III) and arsenic. Glucose, a fermentable and respirable carbon donor, led to the production of 1500 mg Fe(II) kg(-1), or 24% of the total Fe in the aquifer sediment being reduced to Fe(II), whereas the same concentration of carbon as acetate resulted in only 300 mg Fe(II) kg(-1) being produced. The biogenic Fe(II) produced with acetate was exclusively associated with the solid phase whereas with fermentable carbon donors as whey and glucose, 22 and 54% of the Fe(II) was in solution. With fermentation, some of the metabolites appear to be electron shuttling chemicals and chelating agents that facilitate the reductive dissolution of even crystalline Fe(III) oxides. Without the presence of electron shuttling chemicals, only surficial Fe in direct contact with the bacteria was bioavailable, as illustrated when acetate was used. Regardless of carbon donor type and concentration, As concentrations in the water exceeded drinking water standards. The As dissolution appears to have been the result of the direct use of As as an electron acceptor by dissimilatory arsenic reducing bacteria. Our findings indicate that selection of the carbon and energy donor for biostimulation for remediation of chlorinated solvent impacted aquifers may greatly influence the extent of the reductive dissolution of iron minerals in direct competition with dechlorination processes. Biostimulation may also result in a significant release of As to the solution phase, contributing to further contamination of the aquifer.

Evidence that B-lymphocytes carry the nuclear pocket abnormality associated with bovine leukemia virus infection.

Peripheral blood lymphocytes from 3 cows with persistent lymphocytosis were separated on nylon wool columns into nylon wool-adherent and nonadherent populations. The percentage of cells coated with surface immunoglobulin (B-cells) and the frequency of lymphocytic nuclear pockets in each sub-population were then determined. In each case the adherent population consisted predominantly of B-cells with an increased nuclear pocket frequency, whereas the nonadherent cells were 98.99% negative for surface immunoglobulin (non-B-cells) and contained essentially no nuclear pockets. These findings provided additional evidence that the B-subpopulation of cells was highly involved in bovine leukemia oncogenesis.