Production of butanol by Clostridium puniceum in batch and continuous culture

Summary The pink-pigmented, amylolytic and pectinolytic bacterium Clostridium puniceum in anaerobic batch culture at pH 5.5 and 25–30°C produced butan-1-ol as the major product of fermentation of glucose or starch. The alcohol was formed throughout the exponential phase of growth and surprisingly little acetone was simultaneously produced. Furthermore, acetic and butyric acids were only accumulated in low concentrations, and under optimal conditions were completely re-utilised before the fermentation ceased. Thus, in a minimal medium containing 4% w/v glucose as sole source of carbon and energy, after 65 h at 25°C, pH 5.5 all of the glucose had been consumed to yield (g product/100 g glucose utilised) butanol 32, acetone 3 and ethanol 2. Butanol was again the major product of glucose fermentation during phosphate-limited chemostat culture wherein, although the organism eventually lost its capacity to sporulate and to synthesize granulose, production of butanol continued for at least 100 volume changes. Under no growth condition was the organism capable of producing more than 13.3 g l^-1 of butanol. At pH 5.5, growth on pectin was slow and yielded a markedly lesser biomass concentration than when growth was on glucose or starch; acetic acid was the major fermentation product with lower concentrations of methanol, acetone, butanol and butyric acid. At pH 7, growth on all substrates produced virtually no solvents but high concentrations of both acetic and butyric acids.     

Comparative analysis of creatinine and osmolality as urine normalization strategies in targeted metabolomics for the differential diagnosis of asthma and COPD

Introduction

Urine is an ideal matrix for metabolomics investigation due to its non-invasive nature of collection and its rich metabolite content. Despite the advancements in mass spectrometry and ¹H-NMR platforms in urine metabolomics, the statistical analysis of the generated data is challenged with the need to adjust for the hydration status of the person. Normalization to creatinine or osmolality values are the most adopted strategies, however, each technique has its challenges that can hinder its wider application. We have been developing targeted urine metabolomic methods to differentiate two important respiratory diseases, namely asthma and chronic obstructive pulmonary disease (COPD).

Objective

To assess whether the statistical model of separation of diseases using targeted metabolomic data would be improved by normalization to osmolality instead of creatinine.

Methods

The concentration of 32 metabolites was previously measured by two liquid chromatography-tandem mass spectrometry methods in 51 human urine samples with either asthma (n?=?25) or COPD (n?=?26). The data was normalized to creatinine or osmolality. Statistical analysis of the normalized values in each disease was performed using partial least square discriminant analysis (PLS-DA). Models of separation of diseases were compared.

Results

We found that normalization to creatinine or osmolality did not significantly change the PLS-DA models of separation (R²Q²?=?0.919, 0.705 vs R²Q²?=?0.929, 0.671, respectively). The metabolites of importance in the models remained similar for both normalization methods.

Conclusion

Our findings suggest that targeted urine metabolomic data can be normalized for hydration using creatinine or osmolality with no significant impact on the diagnostic accuracy of the model.

     

Biomass changes and trophic amplification of plankton in a warmer ocean

Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3‐D coupled physical‐biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate‐change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 ± 0.05 °C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom‐up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and regional models, imply the need for caution when extending these considerations into higher trophic levels.     

Microcephaly: general considerations and aids to nosology

Microcephaly is defined as an occipito-frontal head circumference (OFC) 2 or more standard deviations below the mean for age and sex using the new Roche et al. [Pediatrics 1987;79:706-712] charts, and corrected for parental OFC by the method of Weaver and Christian [J Pediatr 1980;96:990-994]. "Relative" microcephaly, i.e., a small head on a small child, may be associated with a much better intellectual prognosis than absolute microcephaly, although the average IQ of children with absolute microcephaly ascertained in a normal school system is normal when compared with that of appropriate control children. "Primary" microcephaly means an abnormal OFC at birth (corrected for gestational age and length), and "secondary" microcephaly a normal birth OFC with later, acquired microcephaly due to deceleration of brain growth reflecting infection, trauma, intoxication, metabolic disease, the Rett syndrome, or a true CNS degenerative disease. Some cases of syndromal microcephaly may be associated with normal intelligence including some "primordial dwarfs," children with Dubowitz syndrome, FAS, mild SC-Roberts syndrome, and an occasional Brachmann-de Lange individual. The nosology of (syndromal) microcephaly is extraordinarily complex and requires the assistance of special library resources and information retrieval expertise. At a minimum, it requires McKusick's Catalog of Mendelian Inheritance in Man (MIM); however, we find that our work is greatly enhanced by recently developed electronic databases such as MIM-online (OMIM), POSSUM, SYNDROME, and MEDLINE, as well. Three groups of syndromal and non-syndromal microcephaly are discussed selectively in order to illustrate the marvels of pleiotropy in human development and its abnormalities and the difficulties encountered in splitting and lumping entities with overlapping manifestations.     

A reliable method for assessing rotational power

Rotational core training is said to be beneficial for rotational power athletes. Currently, there has been no method proposed for the reliable assessment of rotational power. Therefore, our purpose was to determine the test-retest reliability of kinetic and kinematic rotational characteristics of a pulley system when performing a rotational exercise of the axial skeleton in the transverse plane to find out if this would be a reliable tool for evaluating rotational power. Healthy, college-aged men (n = 8) and women (n = 15) reported for 3 testing sessions. The participants were seated on a box, and they held the handle with both arms extended in front of their body, starting their motion with their torso rotated toward the machine. All the participants rotated their torso forcefully until they reached 180° of rotation, and they then slowly returned to the starting position, 3 times per trial, with 3 loads: 9% body weight (BW), 12% BW, and 15% BW. The repetition with the greatest power for each trial for each load was analyzed. The mean peak power repetition (watts) for all the subjects was 20.09 ± 7.16 (9% BW), 26.17 ± 8.6 (12% BW), and 30.74 ± 11.022 (15% BW) in the first training session and 22.3 ± 8.087 (9% BW), 28.7 ± 11.295 (12% BW), and 33.52 ± 12.965 (15% BW) in the second training session with intraclass correlation coefficients of 0.97 (9%BW), 0.94 (12%BW), and 0.95 (15%BW). When the participants were separated by sex, there were no significant differences between groups. Based on these results, it was found that a pulley system and an external dynamometer can be used together as a reliable research tool to assess rotational power.     

Greater diversity of Shiga toxin-encoding bacteriophage insertion sites among Escherichia coli O157:H7 isolates from cattle than in those from humans

Escherichia coli O157:H7, a zoonotic human pathogen for which domestic cattle are a reservoir host, produces a Shiga toxin(s) (Stx) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (clusters 1 to 3) among clinical isolates of E. coli O157:H7. Stx-encoding bacteriophage insertion site genotypes of 282 clinical and 80 bovine isolates were evaluated. A total of 268 (95.0%) of the clinical isolates, but only 41 (51.3%) of the bovine isolates, belonged to cluster 1, 2, or 3 (P < 0.001). Thirteen additional genotypes were identified in isolates from both cattle and humans (four genotypes), from only cattle (seven genotypes), or from only humans (two genotypes). Two other markers previously associated with isolates from cattle or with clinical isolates showed similar associations with genotype groups within bovine isolates; the tir allele sp-1 and the Q933W allele were under- and overrepresented, respectively, among cluster 1 to 3 genotypes. Stx-encoding bacteriophage insertion site typing demonstrated that there is broad genetic diversity of E. coli O157:H7 in the bovine reservoir and that numerous genotypes are significantly underrepresented among clinical isolates, consistent with the possibility that there is reduced virulence or transmissibility to humans of some bovine E. coli O157:H7 genotypes.