Metabolic regulation of species-specific developmental rates

Preservation of feline embryos is useful in propagating endangered species, preserving valuable genetics, and supporting biomedical research. Although a wide variety of cryoprotectants (CP) and protocols are successfully used for vitrification of invitro-produced (IVP) embryos, there are often species-specific differences in viability of embryos post-warming. The purpose of this study was to evaluate the viability of IVP feline embryos after vitrification using two common CPs, propanediol (PrOH) or ethylene glycol (EG). Embryos were produced with oocytes and frozen-thawed epididymal sperm collected from local spay-neuter clinics using a published IVP protocol developed for producing domestic feline embryos. Day 7 early blastocysts (stage 5), blastocysts (stage 6), and expanded blastocysts (stage 7) were evaluated for quality (grade 1 or 2) and randomly assigned to one of three treatments: vitrification with PrOH (n=32), vitrification with EG (n=31), or control (n=47), which was allowed to continue in culture until Day 8. The vitrification protocol was as follows. The base medium for all vitrification media was a HEPES-buffered feline optimized culture medium (FOCMH). Embryos were placed in 0.5mL of equilibration medium (7.5% dimethyl sulfoxide, 7.5% PrOH or EG, 0.5M sucrose, 10% Ficoll, and 20% fetal calf serum (FCS)) for 5min at room temperature. Individual embryos were then moved to 20-μL drops of vitrification medium (15% dimethyl sulfoxide, 15% PrOH or EG, 0.5M sucrose, 10% Ficoll, and 20% FCS) at room temperature for 30s before being loaded onto Cryolock devices and plunged into liquid nitrogen. Warming was done using a 3-step process for all vitrified embryos. First, embryos were moved from liquid nitrogen directly to 0.5mL of 1M sucrose, 10% Ficoll, and 20% FCS at 37°C for 1min. Next, embryos were moved to 0.5mL of 0.5M sucrose, 10% Ficoll, and 20% FCS at 20°C for 3min. Finally, embryos were transferred to 0.5mL of FOCMH for 5min at 37°C. All warmed embryos were cultured in medium, optimized for feline embryos, with 5% FCS and evaluated for re-expansion of the blastocoele and progression in development at 24 and 48h. Results are from five replicates. Embryos vitrified in EG exhibited higher percentages of viable embryos 24h after warming (84%) than embryos vitrified in PrOH (59%; P<0.05). The continued embryonic growth of viable embryos after culture for 48h showed equivalent developmental rates, at 87, 96, and 100% for control, EG-treated, and PrOH-treated embryos, respectively (P>0.05). Results indicate EG is a more successful CP treatment for vitrification of feline embryos when evaluating viability 24h post-warming. We report a higher viability of embryos post-thaw than previous studies using the same CPs (Pope et al. 2012 Reprod. Domest. Anim. 47, 125). This may be due to the shorter exposure time to the CPs we used during the vitrification process. We conclude that EG and PrOH are effective CPs for Day 7 feline IVP embryos using this protocol. Further research is needed to increase treatment numbers and evaluate pregnancy rates from embryos transferred post-warming.

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Hormonal regulation in insects: facts, gaps, and future directions

Physiological Reviews ◽

10.1152/physrev.1997.77.4.963 ◽

1997 ◽

Vol 77 (4) ◽

pp. 963-1032 ◽

Cited By ~ 386

Author(s):

G. Gade ◽

K. H. Hoffmann ◽

J. H. Spring

Keyword(s):

Hormonal Regulation ◽

Metabolic Regulation ◽

Color Change ◽

Insect Pest ◽

Neurosecretory Cells ◽

Pheromone Biosynthesis ◽

Functional Studies ◽

Juvenile Hormones ◽

Continue Research ◽

Species Specific

There are two main classes of hormones in insects: 1) the true hormones produced by epithelial glands and belonging to the ecdysteroids or juvenile hormones and 2) the neuropeptide hormones produced by neurosecretory cells. Members of these classes regulate physiological, developmental, and behavioral events in insects. Detailed accounts are given on isolation, identification, structure-activity relationships, mode of action, biological function, biosynthesis, inactivation, metabolism, and feedback for hormones involved in 1) metabolic regulation such as the adipokinetic/hypertrehalosemic peptides and the diuretic and antidiuretic peptides; 2) stimulation or inhibition of muscle activity such as the myotropic peptides; 3) control of reproduction, growth, and development such as allatotropins, allatostatins, juvenile hormones, ecdysteroids, folliculostimulins and folliculostatins, ecdysis-triggering and eclosion hormones, pheromone biosynthesis activating neuropeptides, and diapause hormones; and 4) regulation of tanning and of color change. Because of the improvements in techniques for isolation and structure elucidation, there has been rapid progress in our knowledge of the chemistry of certain neuropeptide families. With the employment of molecular biological techniques, the genes of some neuropeptides have been successfully characterized. There are, however, areas that are still quite underdeveloped. These are, for example, 1) receptor studies, which are still in their infancy; 2) the hormonal status of certain sequenced peptides is not clarified; and 3) functional studies are lacking even for established hormones. The authors plead for a concerted effort to continue research in this field, which will also advance our knowledge into the use of insect hormones as safer and species-specific molecules for insect pest management.

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Variation in developmental rates is not linked to environmental unpredictability in annual killifishes

10.1101/2020.03.16.993329 ◽

2020 ◽

Author(s):

P. K. Rowiński ◽

W. Sowersby ◽

J. Näslund ◽

S. Eckerström-Liedholm ◽

K. Gotthard ◽

...

Keyword(s):

Incubation Temperature ◽

Environmental Variation ◽

Adaptive Plasticity ◽

Bet Hedging ◽

Egg Development ◽

Environmental Predictability ◽

Linear Relationships ◽

In The Wild ◽

Developmental Rates ◽

Species Specific

ABSTRACTComparative evidence suggests that adaptive plasticity may evolve as a response to predictable environmental variation. However, less attention has been placed on unpredictable environmental variation, which is considered to affect evolutionary trajectories by increasing phenotypic variation (or bet-hedging). Here, we examine the occurrence of bet-hedging in egg developmental rates in seven species of annual killifish, which originate from a gradient of variation in precipitation rates, under three treatment incubation temperatures (21°C, 23°C, and 25°C). In the wild, these species survive regular and seasonal habitat desiccation, as dormant eggs buried in the soil. At the onset of the rainy season, embryos must be sufficiently developed in order to hatch and complete their life-cycle. We found substantial differences among species in both the mean and variation of egg development rates, as well as species-specific plastic responses to incubation temperature. Yet, there was no clear relationship between variation in egg development time and variation in precipitation rate (environmental predictability). The exact cause of these differences therefore remains enigmatic, possibly depending on differences in other natural environmental conditions in addition to precipitation predictability. Hence, if species-specific variances are adaptive, the relationship between development and variation in precipitation is complex, and does not diverge in accordance with simple linear relationships.

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Limited evidence for parallel evolution among desert adapted Peromyscus deer mice

10.1101/2020.06.29.178392 ◽

2020 ◽

Author(s):

Jocelyn P. Colella ◽

Anna Tigano ◽

Olga Dudchenko ◽

Arina D. Omer ◽

Ruqayya Khan ◽

...

Keyword(s):

Metabolic Regulation ◽

Molecular Mechanisms ◽

Deer Mouse ◽

Parallel Evolution ◽

Population Level ◽

Deer Mice ◽

Selective Sweeps ◽

Term Survival ◽

Species Specific ◽

Candidate Loci

ABSTRACTPhenotypic plasticity enables an immediate response to changing conditions, but for most species, evolutionary change through adaptation will be more important for long-term survival. Warming climate and increasing desertification urges the identification of genes involved in heat-and dehydration-tolerance to better inform and target biodiversity conservation efforts. Comparisons among extant desert adapted species can highlight parallel or convergent patterns of genome evolution through the identification of shared signatures of selection. We generate chromosome-level genome assembly for the canyon mouse (Peromyscus crinitus) and test for signature of parallel evolution by comparing signatures of selective sweeps across population-level genomic resequencing data from another desert specialist deer mouse (P. eremicus) and a widely-distributed habitat generalist (P. maniculatus), that may locally adapted to arid conditions. We identify few shared candidate loci involved in desert adaptation and do not find support for a shared pattern of parallel evolution. Instead, we hypothesize divergent molecular mechanisms of desert adaptation among deer mice, potentially tied to species-specific historical demography, which may limit or enhance adaptation. We identify a number of candidate loci experiencing selective sweeps in the P. crinitus genome that are implicated in osmoregulation (Trypsin, Prostasin) and metabolic regulation (Kallikrein, eIF2-alpha kinase GCN2, APPL1/2), which may be important to accommodating hot and dry environmental conditions.

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Semiochemical tracks of predaceous Coccinellidae (Coleoptera) modulate feeding attributes and assimilation of nutrients in Zygogramma bicolorata (Coleoptera: Chrysomelidae)

The Canadian Entomologist ◽

10.4039/tce.2020.18 ◽

2020 ◽

Vol 152 (3) ◽

pp. 330-341

Author(s):

Priya Patel ◽

Bhupendra Kumar ◽

Rekha Upadhyay ◽

Daya Ram Bhusal ◽

Dinesh Kumar

Keyword(s):

Biological Control ◽

Growth Rates ◽

The Other ◽

Zygogramma Bicolorata ◽

Reduced Body ◽

The World ◽

Consumption Rates ◽

Developmental Rates ◽

Species Specific ◽

Conversion Efficiencies

AbstractParthenium hysterophorus Linnaeus (Asteraceae) is a toxic weed found abundantly in major agroecosystems of the world. The weed is inhabited by both phytophagous Chrysomelidae (Coleoptera), used as biocontrol agents, and the predaceous Coccinellidae (Coleoptera). The present investigation was designed to assess the feeding attributes and larval development of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) in the presence of semiochemical tracks of coccinellid beetles. Results revealed that the presence of coccinellid semiochemical tracks on the weed reduced larval consumption rates, conversion efficiencies, and growth rates. The feeding deterrent effects of the semiochemical tracks were species specific. Larvae accumulated lower concentrations of glucose, proteins, and triacylglycerols and exhibited reduced body biomass in the presence of semiochemical tracks. The coccinellid semiochemical tracks also promoted Z. bicolorata larvae to accelerate their developmental rates and develop faster than the larvae reared in the absence of semiochemical tracks. While the fourth instars consumed food maximally and were heavier, their food use efficiencies were lower than the other instars. Our findings, therefore, suggest that the presence of semiochemical tracks of coccinellids on P. hysterophorus impedes its biological control by Z. bicolorata larvae.

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Electron Microscopy in the Study of Natural Phytoplankton Assemblages

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119831 ◽

1985 ◽

Vol 43 ◽

pp. 620-623

Author(s):

Linda Sicko-Goad

Keyword(s):

Electron Microscopy ◽

Aquatic Environment ◽

Size Range ◽

Physical Parameters ◽

Specific Information ◽

Phytoplankton Assemblages ◽

Phytoplankton Productivity ◽

Ecosystem Effects ◽

Time Of Year ◽

Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

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