The Iron age of host–microbe interactions

Microbes exert a major impact on human health and disease by either promoting or disrupting homeostasis, in the latter instance leading to the development of infectious diseases. Such disparate outcomes are driven by the ever-evolving genetic diversity of microbes and the countervailing host responses that minimize their pathogenic impact. Host defense strategies that limit microbial pathogenicity include resistance mechanisms that exert a negative impact on microbes, and disease tolerance mechanisms that sustain host homeostasis without interfering directly with microbes. While genetically distinct, these host defense strategies are functionally integrated, via mechanisms that remain incompletely defined. Here, we explore the general principles via which host adaptive responses regulating iron (Fe) metabolism impact on resistance and disease tolerance to infection.     

Relation between age–sex classes and dietary selection of wild Japanese monkeys

Dietary selection by wild Japanese monkeys (Macaca fuscata yakui Kuroda) was examined in relation to body size. The monkeys were classified into three age–sex categories: adult males, adult females and immatures excluding suckling infants. Time spent feeding did not differ between age–sex classes, although time spent moving was longer in lighter classes. Heavier individuals fed relatively more on mature leaves, while lighter individuals fed on insects more frequently. Mature leaves were more abundant but had lower energy content than other food items in the forest. Heavier monkeys seemed to feed on greater amounts of lower quality food in this species. This finding agrees with the Jarman–Bell principle on ungulates.     

When phenology matters: age–size truncation alters population response to trophic mismatch

Climate-induced shifts in the timing of life-history events are a worldwide phenomenon, and these shifts can de-synchronize species interactions such as predator–prey relationships. In order to understand the ecological implications of altered seasonality, we need to consider how shifts in phenology interact with other agents of environmental change such as exploitation and disease spread, which commonly act to erode the demographic structure of wild populations. Using long-term observational data on the phenology and dynamics of a model predator–prey system (fish and zooplankton in Windermere, UK), we show that age–size truncation of the predator population alters the consequences of phenological mismatch for offspring survival and population abundance. Specifically, age–size truncation reduces intraspecific density regulation due to competition and cannibalism, and thereby amplifies the population sensitivity to climate-induced predator–prey asynchrony, which increases variability in predator abundance. High population variability poses major ecological and economic challenges as it can diminish sustainable harvest rates and increase the risk of population collapse. Our results stress the importance of maintaining within-population age–size diversity in order to buffer populations against phenological asynchrony, and highlight the need to consider interactive effects of environmental impacts if we are to understand and project complex ecological outcomes.     

Trends in colorectal cancer incidence in Ho Chi Minh City,Vietnam (1996–2015): Joinpoint regression and age–period–cohort analyses

BackgroundLittle is known about the trends in colorectal cancer (CRC) in Vietnam. We aimed to investigate the trends in epidemiology and anatomical subsites of CRC in Ho Chi Minh City, Vietnam.MethodsBased on the Ho Chi Minh City Cancer Registry data during 1996–2015, we calculated the average annual percent changes (AAPCs) of the age-standardized incidence rates (ASRs) by sex, age groups, and anatomical subsites, using joinpoint regressions analysis. We further performed age–period–cohort (APC) analysis using the United States National Cancer Institute’s web-based statistical tool to explore the underlying reason for the incidence trend.ResultsOver 20 years the overall ASR of CRC increased from 10.5 to 17.9 per 100,000, a 1.7-fold increase. CRC incidence elevated more rapidly in men (AAPC 4.7, 95%CI 2.2–7.3) than in women (AAPC 2.6, 95%CI 0.6–4.8). The highest and lowest increasing rates of ASRs were observed in the 50–64-year-old age group (AAPC 5.3, 95%CI 2.8–7.9) and < 50-year-old age group (AAPC 1.1, 95%CI –0.7 to 2.9), respectively. Regarding subsites, rectal cancer had the highest rate of increase (AAPC 3.3, 95%CI 1.0–5.7). Furthermore, the APC analysis indicated significant increases in CRC incidence in birth cohorts after 1975 in both genders.ConclusionsThe CRC incidence in Ho Chi Minh City increased, with the more prominent rates being among men and older populations, in rectal subsites, and in people born after 1975. The upward trend of CRC incidence in Ho Chi Minh City may be due to the adoption of a westernized lifestyle.     

Characteristics of functional asymmetry in small premature infants at an age of 13–14 months

Delayed consequences of a sharp shortening of the prenatal period for the formation of handedness and the function of visuospatial attention were analyzed. The test group consisted of 16 small premature (SP) children at a corrected age of 13–14 months. The functional asymmetry was assessed by means of the A-not-B neuropsychological task, which is arranged in such a way that a child has to look for an attractive object in either a left or a right location. As compared to healthy children of the same age, the functional asymmetry of SP children was characterized by the absence of right-handedness. During the performance of the A-not-B trials, the SP children displayed a distinct left-side asymmetry: trials with an object hidden to the right of the child were significantly more frequently erroneous than those with a left-side position of the object. It is suggested that SP children have problems with disengagement of the attentional focus from an object located in the left half-field of vision under the conditions of shifting the attention to the right half-field. Probably, one of the consequences of a sharp decrease in the period of prenatal development is abnormal lateralization of some brain functions.     

Trisomy 21 and maternal age of menopause: does reproductive age rather than chronological age influence risk of nondisjunction?

The biological basis underlying the increased risk of nondisjunction in offspring of women of advanced maternal age is not understood. We sought to test the hypothesis that maternal reproductive age (distance in time from approaching menopause) rather than chronological age is pivotal in the etiology of nondisjunction. Our results found no difference in age of menopause between women 30 years old at delivery of a child with trisomy 21 (i.e., age-related nondisjunction) compared to controls. Among women <30 years of age at delivery of a child with trisomy 21, none underwent premature menopause. Therefore, our findings fail to support the theory that reproductive age plays a major role in the etiology of nondisjunction.     

Less inhibited with age? Larval age modifies responses to natural settlement inhibitors

As larvae of marine invertebrates age, their response to settlement cues can change. This change can have significant consequences to both the ecology of these organisms, and to their response to antifouling coatings. This study examines how larval age affects the settlement response of larvae to two naturally derived settlement inhibitors, non-polar extracts from the algae Delisea pulchra and Dilophus marginatus, the former of which contains compounds that are in commercial development as antifoulants. Two species of marine invertebrates with non-feeding larvae were investigated: the bryozoans Watersipora subtorquata and Bugula neritina. Larval age strongly affected larval settlement, with older larvae settling at much higher rates than younger larvae. Despite having strong, inhibitory effects on young larvae, the non-polar extracts did not inhibit the settlement of older larvae to the same degree for both species studied. The results show that the effects of ecologically realistic settlement inhibitors are highly dependent on larval age. Given that the age of settling larvae is likely to be variable in the field, such age specific variation in settlement response of larvae may have important consequences for host-epibiont interactions in natural communities.     

A survey on maternal age and karyotype in Down's syndrome in Japan, 1947–1975

Summary Data on karyotype and maternal age of 1954 cases of Down's syndrome were analyzed to see if the rate of chromosome mutations leading to this abnormality has been enhanced during the last 20 years. Comparison of the data for patients born in 1947–1960 with those in 1961–1975 revealed little change with time in the proportions of cases due to different karyotypes, the overwhelming majority being of 21 trisomy type in both periods. However, there has been a remarkable decline in the mean maternal age from 33.1 years to 29.7 years as well as in the variance from 50.5 to 29.4. While the rate of decline in the variance was almost the same as that for all births occurring in the same periods, the decline in the mean maternal age was much greater for the patients than for all births, suggesting that the rate of nondisjunction might have increased in younger rather than in older mothers. However, when the risk of brearing a child with Down's syndrome for mothers aged 40–44 is taken as unity, no evidence was found for an increase with time in the relative risk for younger mothers. Moreover, results of surveys made in 1960 and thereafter in different parts of Japan indicate that the crude incidence rate of Down's syndrome at birth has been around 0.10%, giving no indication of an upward trend. These findings are discussed with reference to the serious environmental pollution, including possible genetic hazards, with which Japan has been faced since the 1960s.     

Should Flanders consider lowering its target age for colorectal cancer screening to 45–49?

IntroductionColorectal cancer (CRC) screening generally starts screening by the age of 50 based on guidelines. Lately however, a U.S. guideline recommended to start CRC screening from age 45 and, very recently, two studies were published that addressed young-onset in Europe (in part) (Vuik et al., 2019; Araghi et al., 2019).Materials and MethodsFlemish CRC incidence and mortality data contextualise trend results for age groups under 50 and what the implications could be for practice.ResultsCRC incidence rates showed considerable variability over a 12-year period without a clear increase in disease burden for the age group 45–49 in Flanders. In several age groups under 39 an increasing incidence trend was visible for both genders. Data was analysed in a period where no CRC screening was present in Flanders.DiscussionDecreasing the target age for the Flemish CRC screening does not seem to be straightforward and primary prevention should be considered more prominently.     

A strong genetic correlation underlying a behavioural syndrome disappears during development because of genotype–age interactions

In animal populations, as in humans, behavioural differences between individuals that are consistent over time and across contexts are considered to reflect personality, and suites of correlated behaviours expressed by individuals are known as behavioural syndromes. Lifelong stability of behavioural syndromes is often assumed, either implicitly or explicitly. Here, we use a quantitative genetic approach to study the developmental stability of a behavioural syndrome in a wild population of blue tits. We find that a behavioural syndrome formed by a strong genetic correlation of two personality traits in nestlings disappears in adults, and we demonstrate that genotype–age interaction is the likely mechanism underlying this change during development. A behavioural syndrome may hence change during organismal development, even when personality traits seem to be strongly physiologically or functionally linked in one age group. We outline how such developmental plasticity has important ramifications for understanding the mechanistic basis as well as the evolutionary consequences of behavioural syndromes.     

Age–age and trait–trait correlations for <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> Hill ex Maiden and their implications for optimal selection age and design of clonal trials

Previous results from seven locations of Eucalyptus grandis clonal trials in Colombia supported the a priori contention of sub-dividing them into three different environmental zones for testing and deployment. Within these zones, the determination of age-age genetic correlations for both height and mean annual increment (MAI) showed that strong age-age correlations are present for a rotation age of 6 years starting at 3 years age and, thereafter, suggesting this age as appropriate for selection. This biological selection age coincides with an "economical" age for selection based on discounted selection efficiency in perpetuity, considering a range of interest rates between 10% and 20%. High genetic correlations between wood density at 3 years and 6 years as well as the lack of genetic correlation between this trait and growth traits, also favors selection at age 3 and facilitates breeding strategies that consider the utilization of both traits for improvement. A simulation of optimal clonal test designs indicated that by using six locations and six blocks per location in a single-tree plot design, between 80% and 90% of the maximum selection efficiency could be obtained. This type of design allows testing of a large number of genotypes across a reasonable number of locations in a cost-effective manner.     

Changes in the protein–polysaccharides of pig articular cartilage during prenatal life, development and old age

Analysis of the knee-joint cartilage of pigs at five ages (namely foetuses from the second half of pregnancy and animals 10 weeks, 25 weeks, 3 years and 5 years old) showed that the composition approached that of adult cartilage by 25 weeks of age, the most marked differences being between foetal and 10 week-old cartilage. Protein-polysaccharides were extracted sequentially, first by brief low-speed homogenization with iso-osmotic sodium acetate, then by two extractions with 2m-CaCl(2) for 24h with gentle agitation interspersed with brief low-speed homogenization and agitation for another 24h. About half of the protein-polysaccharides were removed from foetal cartilage by the first extraction and the remainder by the second. The proportion in the first extract declined sharply with the age of the animal, but that in the first CaCl(2) extract was similar at all ages other than 10 weeks. The amount left in the residue increased approximately with the collagen content from about one-fifth at 10 weeks of age to one-third in adult and old cartilage. The proportion of medium-sized protein-polysaccharides in the extracts changed little with age after birth, but the glucosamine content increased about fivefold and the protein content almost doubled between 10 weeks and 5 years of age. Other analytical values changed little. These results cannot be explained solely by changes in the proportion of ;link-glycoprotein' in the protein-polysaccharides. Since major changes in most parameters had taken place by 25 weeks of age, the first weeks after birth may be a critical period for cartilage development in the pig.     

Teacher–child interaction quality as a function of classroom age diversity and teachers’ beliefs and qualifications

Data from 332 teachers who participated in the National Center for Research on Early Childhood Education study were used to examine the implications of classroom age diversity in preschool programs for teacher interactions with students in areas of instructional and emotional support, and classroom organization. Teachers in early childhood classrooms with greater age diversity within a school year and who experienced an increase in age diversity across years exhibited less optimal teacher–child interactions. The negative effects of age diversity for teacher–child interactions were only noticeable among teachers with fewer years of education and experience, and among teachers whose views of children were less child-centered. When taken together, results indicate that closer attention should be paid to the consequences of classroom age diversity in preschool and that a multi-year perspective on teachers’ classroom experiences would allow for a more nuanced understanding of the quality of teacher–child interactions.     

Have biopesticides come of age?

Biopesticides based on living microbes and their bioactive compounds have been researched and promoted as replacements for synthetic pesticides for many years. However, lack of efficacy, inconsistent field performance and high cost have generally relegated them to niche products. Recently, technological advances and major changes in the external environment have positively altered the outlook for biopesticides. Significant increases in market penetration have been made, but biopesticides still only make up a small percentage of pest control products. Progress in the areas of activity spectra, delivery options, persistence of effect and implementation have contributed to the increasing use of biopesticides, but technologies that are truly transformational and result in significant uptake are still lacking.     

Patterns in self-rated health according to age and sex in a Japanese national survey, 1989–2004

Background: Perceived good health or good self-rated health is considered to be a predictor of longer survival and maintenance of good quality of life, which is a public health goal.Objective: This study assessed trends in the percentage of self-rated poor health among Japanese residents, based on data from the National Comprehensive Survey of the Living Conditions of People on Health and Welfare.Methods: Results of the survey (which is conducted in Japan every 3 years to determine the living conditions of people receiving health and welfare services) were analyzed using multistage and stratified cluster sampling of households. Self-rated health was measured by response to the question, “Recently, would you say that in general your health has been good, fairly good, fair, fairly poor, or poor?” The trend in fairly poor or poor health status during the period from 1989 through 2004 was stratified by sex and age group.Results: The rates of response to the survey were 90.9% (246,892/271,588) in 1995 and 79.8% (220,836/276,682) in 2004. Target subjects were aged ≥20 years in each year of the study. The prevalence of self-reported fairly poor or poor health was lowest in 1995 and then increased every year until 2001, when it appeared to reach a plateau. The prevalence of having fairly poor or poor health among women aged 35 to 44, 45 to 54, 55 to 64, and 65 to 74 years were as follows in 1995: 9.2%, 11.7%, 15.3%, and 19.8%, respectively. In 2004, the rates were 13.3%, 17.2%, 22.1%, and 31.7%, respectively. By comparison, the prevalence of self-reported fairly poor or poor health was 8.1%, 9.3%, 13.7%, and 17.9% among men aged 35 to 44, 45 to 54, 55 to 64, and 65 to 74 years, respectively, in 1995. In 2004, these rates were 12.8%, 14.8%, 19.0%, and 27.9%, respectively.Conclusions: In this survey, conducted every 3 years between 1989 and 2004 in Japanese households, older subjects had a greater prevalence of self-reported fairly poor or poor health than did younger subjects. The proportion of respondents who described their health as poor or fairly poor was highest in 1995. Women generally had a greater prevalence of self-reported poor or fairly poor health.     

U–Pb SHRIMP age for the Tuchengzi Formation,northern China,and its implications for biotic evolution during the Jurassic–Cretaceous transition

The Late Jurassic–Early Cretaceous Tuchengzi Formation is widespread in North China. Its clastic deposits indicate a tropical, dry, and hot paleoclimate, different from the subtropical, humid, and seasonal climate in the early Middle Jurassic. The sudden environmental change from the Middle to Late Jurassic resulted in a rapid disappearance of the Yanliao/Daohugou Biota, with more than 90% of the species of the Yanliao/Daohugou Biota dying out and replaced by the Early Cretaceous Jehol Biota. Eolian sandstones with large-scale cross-bedding occur within the uppermost part of the Tuchengzi Formation in North China. The sandstones are stratigraphically higher than the tuff previously dated as 139 Ma. We obtained two SHRIMP zircon U/Pb ages from the tuff beds. One sample was collected from the tuff in the basal Tuchengzi Formation in northern Hebei and the other from the tuff intercalated in the eolian cross-bedded sandstones in the uppermost Tuchengzi Formation in western Liaoning. Our results show that 154 Ma is the oldest age constraint for the Tuchengzi Formation and 137 Ma is the youngest age estimate of the formation, providing an age constraint for the transition from the Yanliao Biota to the Jehol Biota.     

Establishment and follow-up of bifidobacterial species in the gut of healthy bottle-fed infants of 1–4 months age

Twenty-one healthy bottle-fed infants were screened monthly (1-4 months) for bifidobacteria in their stools. Bifidobacteria were detected by culture and isolates specified by PCR. Alternatively, direct PCR in undiluted fecal suspensions was carried out for detection of bifidobacteria under the cultural detection level. All infants harbored cultivable bifidobacteria throughout the study period. Beerens medium was shown to permit a better recovery of bifidobacteria than MRS and horse blood Columbia agar. Direct PCR detection proved valuable in detecting species for which no cultural isolate could be recovered since the species were under the cultural detection level. B. bifidum, B. longum-infantis and B. breve were confirmed as dominant and stable species in infant stools while B. adolescentis and B. catenulatum group exhibited unstable colonization profiles. A trend towards B. breve decrease began at month 3 while carriage of the B. catenulatum group and B. adolescentis was rising. This observation warrants further analysis to assess a possible switch occurring at month 3 in bottle-fed infants, between so-called infant and adult bifidobacterial species.