scholarly journals The Quick and the Dead: Microbial Demography at the Yeast Thermal Limit

2016 ◽  
Author(s):  
Colin S. Maxwell ◽  
Paul M. Magwene
Keyword(s):  
Heat Stress ◽  
Early Life ◽  
Asymmetric Cell Division ◽  
Significant Heterogeneity ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genotype By Environment ◽  
Environment Effects ◽  
High Death ◽  
Cell Measurement ◽  
Age Structured

AbstractThe niche of microorganisms is determined by where their populations can expand. Populations can fail to grow because of high death or low birth rates, but these are challenging to measure in microorganisms. We developed a novel technique that enables single cell measurement of age-structured birth and death rates in the budding yeast, Saccharomyces cerevisiae, and used this method to study responses to heat stress in a genetically diverse panel of strains. We find that individual cells show significant heterogeneity in their rates of birth and death during heat stress. Genotype-by-environment effects on processes that regulate asymmetric cell division contribute to this heterogeneity. These lead to either premature senescence or early life mortality during heat stress, and we find that a mitochondrial inheritance defect explains the early life mortality phenotype of one of the strains we studied. This study demonstrates how the interplay of physiology, genetic variation, and environmental variables influences where microbial populations survive and flourish.

scholarly journals Genotype-by-environment interaction in Holstein heifer fertility traits using single-step genomic reaction norm models

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Shi ◽  
Luiz Fernando Brito ◽  
Aoxing Liu ◽  
Hanpeng Luo ◽  
Ziwei Chen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Dairy Cattle ◽  
Candidate Genes ◽  
Heat Tolerance ◽  
Reaction Norm ◽  
Single Step ◽  
Conception Rate ◽  
Critical Periods ◽  
Genotype By Environment ◽  
Fertility Traits

Abstract Background The effect of heat stress on livestock production is a worldwide issue. Animal performance is influenced by exposure to harsh environmental conditions potentially causing genotype-by-environment interactions (G × E), especially in highproducing animals. In this context, the main objectives of this study were to (1) detect the time periods in which heifer fertility traits are more sensitive to the exposure to high environmental temperature and/or humidity, (2) investigate G × E due to heat stress in heifer fertility traits, and, (3) identify genomic regions associated with heifer fertility and heat tolerance in Holstein cattle. Results Phenotypic records for three heifer fertility traits (i.e., age at first calving, interval from first to last service, and conception rate at the first service) were collected, from 2005 to 2018, for 56,998 Holstein heifers raised in 15 herds in the Beijing area (China). By integrating environmental data, including hourly air temperature and relative humidity, the critical periods in which the heifers are more sensitive to heat stress were located in more than 30 days before the first service for age at first calving and interval from first to last service, or 10 days before and less than 60 days after the first service for conception rate. Using reaction norm models, significant G × E was detected for all three traits regarding both environmental gradients, proportion of days exceeding heat threshold, and minimum temperature-humidity index. Through single-step genome-wide association studies, PLAG1, AMHR2, SP1, KRT8, KRT18, MLH1, and EOMES were suggested as candidate genes for heifer fertility. The genes HCRTR1, AGRP, PC, and GUCY1B1 are strong candidates for association with heat tolerance. Conclusions The critical periods in which the reproductive performance of heifers is more sensitive to heat stress are trait-dependent. Thus, detailed analysis should be conducted to determine this particular period for other fertility traits. The considerable magnitude of G × E and sire re-ranking indicates the necessity to consider G × E in dairy cattle breeding schemes. This will enable selection of more heat-tolerant animals with high reproductive efficiency under harsh climatic conditions. Lastly, the candidate genes identified to be linked with response to heat stress provide a better understanding of the underlying biological mechanisms of heat tolerance in dairy cattle.

scholarly journals Replicative Aging in Pathogenic Fungi

2020 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Somanon Bhattacharya ◽  
Tejas Bouklas ◽  
Bettina C. Fries
Keyword(s):  
Cell Division ◽  
Candida Glabrata ◽  
Asymmetric Cell Division ◽  
Pathogenic Fungi ◽  
Yeast Cells ◽  
Candida Auris ◽  
Replicative Aging ◽  
Yeast Saccharomyces Cerevisiae ◽  
Phenotypic Variations ◽  
Systemic Infections

Candida albicans, Candida auris, Candida glabrata, and Cryptococcus neoformans are pathogenic yeasts which can cause systemic infections in immune-compromised as well as immune-competent individuals. These yeasts undergo replicative aging analogous to a process first described in the nonpathogenic yeast Saccharomyces cerevisiae. The hallmark of replicative aging is the asymmetric cell division of mother yeast cells that leads to the production of a phenotypically distinct daughter cell. Several techniques to study aging that have been pioneered in S. cerevisiae have been adapted to study aging in other pathogenic yeasts. The studies indicate that aging is relevant for virulence in pathogenic fungi. As the mother yeast cell progressively ages, every ensuing asymmetric cell division leads to striking phenotypic changes, which results in increased antifungal and antiphagocytic resistance. This review summarizes the various techniques that are used to study replicative aging in pathogenic fungi along with their limitations. Additionally, the review summarizes some key phenotypic variations that have been identified and are associated with changes in virulence or resistance and thus promote persistence of older cells.

scholarly journals The performance of true seed shallot lines under different environments of Ethiopia

2014 ◽  
Vol 59 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Aklilu Shimeles
Keyword(s):  
Regression Coefficient ◽  
Small Deviation ◽  
Environmental Index ◽  
Combined Analysis ◽  
Genotype By Environment ◽  
Environment Effects ◽  
True Seed ◽  
The Mean ◽  
Growing Conditions ◽  
Bulb Yield

Seven true seed shallot lines were evaluated for 3 years at 3 locations to determine their performance and stability. Stability differences were assessed on the basis of linear regression of the lines on environmental index and on deviation from linear function along with the mean yield. The combined analysis showed that bulb yield over 9 environments ranged from 15.1 to 17.5 t ha-1 with overall mean yield of 16.5 t ha-1, and lines Vethalam, Tropix, Dz-94 and Athlas gave the highest mean yield. The combined analysis of variance showed significant (p<0.05) genotype and genotype by environment effects on bulb yield. The regression coefficient for bulb yield ranged from 0.72 to 1.36. The regression coefficient of two high yielding lines (Vethalam and Athlas) was above 1, and was higher in environments where growing conditions were favorable. High and significant deviations were obtained for lines Tropix and Athlas and these lines were found unstable to change in environment. However, line Tropix showed specific adaptation to low yielding environments of Kulumsa and Melkassa. The best line Vethalam with a small deviation from regression was found widely adaptable to different environments and it was released with local name ?Yeras? to be grown in Rift Valley and similar areas in Ethiopia.

scholarly journals Late-Gestation in utero Heat Stress Limits Dairy Heifer Early-Life Growth and Organ Development

2021 ◽  
Vol 2 ◽  
Author(s):  
Bethany Dado-Senn ◽  
Sena L. Field ◽  
Brittney D. Davidson ◽  
Leticia T. Casarotto ◽  
Marcela G. Marrero ◽  
...  
Keyword(s):  
Heat Stress ◽  
Early Life ◽  
Average Daily Gain ◽  
In Utero ◽  
Late Gestation ◽  
Whole Body ◽  
Metabolic Adaptation ◽  
Heart Weight ◽  
Dairy Calf ◽  
The Relationship

Dairy calves exposed to late-gestation heat stress weigh less, have impaired immunity, produce less milk across multiple lactations, and have reduced productive life. However, less is known about the relationship between in utero heat stress and organ morphology and development. Herein, we characterized the consequences of late-gestation in utero heat stress on body and organ growth trajectories during early-life development. Holstein heifers were either in utero heat-stressed (IU-HT, n = 36, dams exposed to THI &gt; 68) or cooled (IU-CL, n = 37, dams exposed to THI &gt; 68 with access to active cooling) during late gestation (54 ± 5 d prepartum). All heifers were reared identically from birth to weaning. Upon birth, calves were weighed and fed 3.78 L of colostrum followed by 0.87 kg DM/d milk replacer (MR) over two feedings and ad libitum starter concentrate daily. Weaning began at 49 d and ended at 56 d of age. Feed intake was recorded daily, and body weight (BW) and other growth measures were recorded at 0, 28, 56, and 63 d. Blood was collected at d 1 then weekly. Subsets of heifers were selected for euthanasia at birth and 7 d after complete weaning (n = 8 per group each) to harvest and weigh major organs. Reduced BW and stature measures persisted in IU-HT heifers from 0 to 63 d of age with a 7% lower average daily gain and reduced starter consumption relative to IU-CL heifers. IU-HT heifers had lower hematocrit percentages and reduced apparent efficiency of absorption of IgG relative to IU-CL heifers. Additionally, IU-HT heifers had reduced gross thymus, spleen, thyroid gland, and heart weight at birth and larger adrenal glands and kidneys but smaller ovaries relative to BW at 63 d. The mammary gland of IU-HT heifers was smaller relative to IU-CL heifers at birth and 63 d adjusted for BW, suggesting mechanisms leading to impaired milk yield in mature IU-HT cows are initiated early in development. In summary, in utero heat stress reduces whole-body size and limits development of key organs with potential repercussions on dairy calf metabolic adaptation, immune function, and future productivity.

Sign in / Sign up

Export Citation Format

Share Document