scholarly journals Probing Pedomorphy and Prolonged Lifespan in Naked Mole-Rats and Dwarf Mice

Physiology ◽  
2020 ◽  
Vol 35 (2) ◽  
pp. 96-111 ◽  
Author(s):  
Rochelle Buffenstein ◽  
Kaitlyn N. Lewis ◽  
Patrick A. Gibney ◽  
Vikram Narayan ◽  
Kelly M. Grimes ◽  
...  
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Slow Growth ◽  
Hormone Levels ◽  
Dwarf Mice

Pedomorphy, maintenance of juvenile traits throughout life, is most pronounced in extraordinarily long-lived naked mole-rats. Many of these traits (e.g., slow growth rates, low hormone levels, and delayed sexual maturity) are shared with spontaneously mutated, long-lived dwarf mice. Although some youthful traits likely evolved as adaptations to subterranean habitats (e.g., thermolability), the nature of these intrinsic pedomorphic features may also contribute to their prolonged youthfulness, longevity, and healthspan.

Studies on the sowing dates of cotton in the Sudan Gezira: I. The influence of date of sowing on plant growth and development

1967 ◽  
Vol 69 (3) ◽  
pp. 305-315 ◽  
Author(s):  
J. E. Jackson
Keyword(s):  
Growth Rates ◽  
Slow Growth ◽  
Seasonal Pattern ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Research Division ◽  
Sowing Dates ◽  
Net Assimilation ◽  
State Growth ◽  
Sudan Gezira

Growth analysis of cotton crops sown in the Sudan Gezira at monthly intervals between August and May revealed a marked seasonal pattern of growth. Irrespective of plant age and fruiting state growth of non-senescent plants was slowest during the cool winter months. Relative growth rates of young plants were highest in August, September and early October due to the high specific leaf areas and fairly high net assimilation rates found then. They were lowest when minimum temperatures were lowest. Net assimilation rates were also lowest in the coolest months, probably as a result of restricted growth. High temperatures in the spring reduced fruiting. It is concluded that low minimum temperatures and high evaporation rates are both associated with slow growth, and play a large part in determining the characteristic decline of growth rates of cotton sown at the usual date in August.I wish to thank the Chief of the Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper and to record my gratitude to the team of field and laboratory assistants, especially Salih Saad and Hassan Osman, who helped in the work.

Relationships Between RNA–DNA Ratio, Prey Density, and Growth Rate in Atlantic Cod (Gadus morhua) Larvae

1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley
Keyword(s):  
Growth Rate ◽  
Nutritional Status ◽  
Growth Rates ◽  
Prey Density ◽  
Gadus Morhua ◽  
Slow Growth ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Dry Weight ◽  
Dna And Rna

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod

scholarly journals Chromosome segregation in B. subtilis is highly heterogeneous

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Nina El Najjar ◽  
Peter L. Graumann
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Chromosome Segregation ◽  
Growth Rates ◽  
Slow Growth ◽  
Growth Conditions ◽  
Single Chromosome ◽  
Copy Numbers ◽  
Initiation Of Replication ◽  
Bacterial Cell Cycle

Abstract Objective The bacterial cell cycle comprises initiation of replication and ensuing elongation, concomitant chromosome segregation (in some organisms with a delay termed cohesion), and finally cell division. By quantifying the number of origin and terminus regions in exponentially growing Bacillus subtilis cells, and after induction of DNA damage, we aimed at determining cell cycle parameters at different growth rates at a single cell level. Results B. subtilis cells are mostly mero-oligoploid during fast growth and diploid during slow growth. However, we found that the number of replication origins and of termini is highly heterogeneous within the cell population at two different growth rates, and that even at slow growth, a majority of cells attempts to maintain more than a single chromosome at all times of the cell cycle. Heterogeneity of chromosome copy numbers may reflect different subpopulations having diverging growth rates even during exponential growth conditions. Cells continued to initiate replication and segregate chromosomes after induction of DNA damage, as judged by an increase in origin numbers per cell, showing that replication and segregation are relatively robust against cell cycle perturbation.

Selection on growth rates via a trade-off between survival to sexual maturity and longevity in the swordtail fish Xiphophorus multilineatus

2019 ◽  
Vol 33 (4) ◽  
pp. 549-566 ◽  
Author(s):  
Michael Weinstein ◽  
Melissa N. Liotta ◽  
Aaron Solitt ◽  
Adam Hunt ◽  
Jessica K. Abbott ◽  
...  
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Trade Off ◽  
Swordtail Fish

What drives the vital rates of secondary hemiepiphytes? A first assessment for three species of Heteropsis (Araceae) in the Colombian Amazon

2015 ◽  
Vol 31 (3) ◽  
pp. 251-265 ◽  
Author(s):  
María Paula Balcázar-Vargas ◽  
Tinde R. van Andel ◽  
Paul Westers ◽  
Pieter A. Zuidema
Keyword(s):  
Growth Rates ◽  
Vegetative Propagation ◽  
Slow Growth ◽  
Gradual Increase ◽  
Leaf Size ◽  
Stem Length ◽  
Vital Rates ◽  
Size Number ◽  
Colombian Amazon ◽  
Study Species

Abstract:Secondary hemiepiphytes rely on other plants (hosts) to grow vertically. After germinating on the forest floor, their seedlings search a host to ascend. We recorded information on survival, growth, reproduction and vegetative propagation of three Heteropsis species, to evaluate what drives their vital rates. We measured 700 individuals of each study species between 2007 and 2009 in the southern Colombian Amazon. A gradual increase in stem length, leaf size, number of roots and plagiotropic branches was found with increasing height of Heteropsis individuals on their hosts. Survival of leafless non-climbing seedlings was very low (28% annually); increasing substantially (84–94%) once the seedling had ascended a host. The three Heteropsis species presented slow height growth rates (c. 2–8 cm y−1) with large variation, while a substantial percentage of the stems (31–62%) did not grow or dried out. Vegetative propagation in Heteropsis may act as a dispersion-propagation strategy to find a suitable host and reach the canopy again after falling. The slow growth rates suggest that Heteropsis individuals that have reached the canopy are rather old. Once plants have reached the tree crowns, their longevity is largely determined by the survival of the host tree.

scholarly journals Impact of Feed Rations on Growth, Selected Body Parameters and Maturation of Vendace, Coregonus Albula L., Reared in RAS

2014 ◽  
Vol 22 (2) ◽  
pp. 145-150
Author(s):  
Bożena Szczepkowska ◽  
Mirosław Szczepkowski ◽  
Iwona Piotrowska
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Fish Growth ◽  
Coregonus Albula ◽  
Body Weights ◽  
Intensive Rearing ◽  
Mature Fish ◽  
Final Survival ◽  
Body Parameters ◽  
Commercial Size

Abstract Vendace, Coregonus albula L., was reared to commercial size in a recirculating system. Three different feed rations were applied during the ten-month-long experiment. The feed rations impacted fish growth rates, and fish in the different groups achieved body weights of 26.6 g to 57.5 g. The final survival in all groups was similar from 44.3% among the fish fed the smallest feed ration to 53.2% in the group receiving the largest feed ration. No differences were noted in the share of viscera, peritoneal fat, or in the hepatosomatic indexes, but there were differences in the gonadosomatic indexes. After thermal stimulation, only males achieved sexual maturity. The number of mature fish was similar in all groups and ranged from 17.8 to 21.3% of all fish. The results of the present study indicated that vendace can achieve commercial size in an intensive rearing period of ten months in RAS.

Age, Growth, and Sexual Maturity of the Shorthorn Sculpin, Myoxocephalus scorpius, in Newfoundland Waters

1970 ◽  
Vol 27 (12) ◽  
pp. 2155-2158 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Average Length ◽  
Maximum Size ◽  
Age Group ◽  
Younger Age ◽  
Shorthorn Sculpin ◽  
Males And Females ◽  
The Difference ◽  
Myoxocephalus Scorpius

In Newfoundland waters, shorthorn sculpins, Myoxocephalus scorpius (L.), live to age 15 and attain a maximum size of just over 50 cm. The growth rates of males and females are little different below age 4, but above age 4 the females grow faster than the males, and the difference between average length-at-age for males and females gets progressively larger with age. Males mature at a younger age and at a smaller size than females. In any age-group where there are mature and immature individuals the mature ones are larger.

Adaptation and evolution in Gallotia lizards from the Canary Islands: age, growth, maturity and longevity

1991 ◽  
Vol 12 (1) ◽  
pp. 81-102 ◽  
Author(s):  
Jacques Castanet ◽  
Marcos Baez
Keyword(s):  
Canary Islands ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Maximum Size ◽  
Adaptive Strategies ◽  
Relative Growth ◽  
Qualitative And Quantitative ◽  
Evolutionary Features ◽  
Histological Data

AbstractQualitative and quantitative comparisons of histological data recorded from growing bone from seven extant and extinct taxa of Gallotia show that these lizards do not have the same longevity, reach sexual maturity at various ages and probably have different growth rates which are in reverse proportion to the specific size of individuals in each taxon. In term of relative growth, the highest rate is seen in the smallest taxon (G. atlantica) and the lowest in the largest taxon (G. goliath). It appears that differences between the maximum size reached, irrespective of the size of hatchlings, are only the consequence of changes in longevity allowing a more or less protracted growth; they are not due to differences in growth rates. On the basis of these data we discuss some points relating to adaptive strategies and evolutionary features of these lizards.

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