Substrate Utilization and Competitive Interactions Among Soil Bacteria Vary With Life-History Strategies

Microorganisms have evolved various life-history strategies to survive fluctuating resource conditions in soils. However, it remains elusive how the life-history strategies of microorganisms influence their processing of organic carbon, which may affect microbial interactions and carbon cycling in soils. Here, we characterized the genomic traits, exometabolite profiles, and interactions of soil bacteria representing copiotrophic and oligotrophic strategists. Isolates were selected based on differences in ribosomal RNA operon (rrn) copy number, as a proxy for life-history strategies, with pairs of “high” and “low” rrn copy number isolates represented within the Micrococcales, Corynebacteriales, and Bacillales. We found that high rrn isolates consumed a greater diversity and amount of substrates than low rrn isolates in a defined growth medium containing common soil metabolites. We estimated overlap in substrate utilization profiles to predict the potential for resource competition and found that high rrn isolates tended to have a greater potential for competitive interactions. The predicted interactions positively correlated with the measured interactions that were dominated by negative interactions as determined through sequential growth experiments. This suggests that resource competition was a major force governing interactions among isolates, while cross-feeding of metabolic secretion likely contributed to the relatively rare positive interactions observed. By connecting bacterial life-history strategies, genomic features, and metabolism, our study advances the understanding of the links between bacterial community composition and the transformation of carbon in soils.

Faster, better, and cheaper: harnessing microfluidics and mass spectrometry for biotechnology

High-throughput screening technologies are widely used for elucidating biological activities. These typically require trade-offs in assay specificity and sensitivity to achieve higher throughput. Microfluidic approaches enable rapid manipulation of small volumes and have found a wide range of applications in biotechnology providing improved control of reaction conditions, faster assays, and reduced reagent consumption. The integration of mass spectrometry with microfluidics has the potential to create high-throughput, sensitivity, and specificity assays. This review introduces the widely-used mass spectrometry ionization techniques that have been successfully integrated with microfluidics approaches such as continuous-flow system, microchip electrophoresis, droplet microfluidics, digital microfluidics, centrifugal microfluidics, and paper microfluidics. In addition, we discuss recent applications of microfluidics integrated with mass spectrometry in single-cell analysis, compound screening, and the study of microorganisms. Lastly, we provide future outlooks towards online coupling, improving the sensitivity and integration of multi-omics into a single platform.

Vitality and malaise in demography: outlook and strategies for the future

"When dealing with age structures...the question could be posed...whether in the age structure such pronounced 'distortions' already exist as to make a major contribution to plotting the course of demography and then, as a more or less inevitable consequence, to shaping the social and economic context. In other words, whether conditions of 'demographic malaise' exist linked, on the one hand, to an extraordinarily young age structure and a consequent 'excess' population growth...and, on the other, to an extraordinarily old age structure and a subsequent 'excess' population decline.... This study proposes to focus particularly on this second instance, which pertains to contemporary western populations or sub-populations, [using the example of Italy]."

On the use of health surveys for estimating transition rates for morbidity processes

"In this paper, we describe a potential source of useful data for estimating disease onset, recovery and death rates, and derive the necessary equations for estimating the rates. The limitations of the method, both theoretical and practical, are described, and numerical results are reported in the cases of two Italian health surveys of the 1980s.... Our goal in this paper is to study quality of life, and to attempt to provide measures which may allow health policy decisions affecting quality of life. For this purpose, estimates of morbidity provided by general population health surveys would seem to be appropriate." (SUMMARY IN FRE AND ITA)

[An adjustment to the age structure of the Italian population in the 1971 census]

"Having verified, in the 1971 [Italian] census, the presence of certain anomalous data for cohorts born in 1900, 1911, 1920, 1924, 1930, 1936, 1940, 1948, 1950 and 1960, we assessed the size of the error and estimated the new population total which emerged both by age and year of birth. The method used [is similar] to more classical methods to correct biases in age structure in previous censuses and in those countries where the data available are somewhat lacking. The adjusted values, referring to Italy as a whole, are contained in the text...." (SUMMARY IN ENG AND FRE)

A method for the estimation of chronic disease morbidity and trends from mortality data

Measures of chronic degenerative disease diffusion, such as incidence and prevalence rates, are a basic need for epidemiologists and others working in many fields of human sciences. Equations relating death probabilities to incidence and survival probabilities for chronic degenerative diseases are derived from a cohort point of view. A maximum likelihood approach is adopted for the estimation of incidence as a function of time related covariates. When time series of mortality data are available, the model can be used to describe and analyse levels and dynamics of morbidity. A trial application to lung and breast cancer is given for the province of Varese, Italy, where incidence data are available from the Lombardy Cancer Register.

[The impact of excess male mortality on sex structure. The Italian case, 1951-1981]

The purpose of this note is to analyze male excess mortality in relation to general mortality trends in a country with low levels of mortality, using Italian data for the period 1951-1981, and to examine the effect of this excess male mortality on the sex distribution of the population. Consideration is given to the apparent paradox whereby "at least during the first half of life, the sex ratio increases when excess male mortality increases. This paradox shows that the index traditionally used for measuring the disadvantage of men with regard to survival, is not the most appropriate one." (SUMMARY IN ENG AND SPA)