Thermal dependence of size-at-hatch in the lake whitefish (Coregonus clupeaformis)

2019 ◽  
Vol 76 (11) ◽  
pp. 2069-2079 ◽  
Author(s):  
Charles Mitz ◽  
Christopher Thome ◽  
Mary Ellen Cybulski ◽  
Christopher M. Somers ◽  
Richard G. Manzon ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Morphological Characteristics ◽  
Development Stage ◽  
Dominant Factor ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Thermal Dependence ◽  
Break Up ◽  
The Difference ◽  
Incubation Temperatures

Lake whitefish (Coregonus clupeaformis) embryos incubated at low temperatures have a longer incubation period and hatch at a significantly greater size than those incubated at warmer temperatures. We examined hatch timing and morphological characteristics for whitefish embryos reared under different constant and varying temperatures to determine whether the thermal dependence of hatching size reflects differences in their development stage. Our results show that lake whitefish embryos hatch at different temperature-dependent developmental stages, and this is the dominant factor affecting size-at-hatch. The term “heterograde” is proposed for the thermal dependence of hatching stage to differentiate it from hatching that occurs at a fixed developmental stage. A method to quantify this effect is given using a ratio that describes the difference in relative development at hatching between different viable constant incubation temperatures. Heterograde hatching is proposed as a possible mechanism to synchronize the timing of hatch to the break-up of winter ice cover despite variability in the date of spawning and in the onset of spring break-up.

Electron Microscopy of California Isolate of Cat Leukemia Virus

1968 ◽  
Vol 26 ◽  
pp. 24-25
Author(s):  
T. G. Kawakami ◽  
G. H. Theilen ◽  
R. J. Munn
Keyword(s):  
Plasma Membrane ◽  
Developmental Stages ◽  
Leukemia Virus ◽  
Morphological Characteristics ◽  
Host Cells ◽  
Stage Of Development ◽  
Viral Particles ◽  
The Difference ◽  
Vacuolar Membranes ◽  
Electron Lucent

Although “C”-type viral particles have been observed in oats with feline leukemia, the developmental stages, morphological characteristics and sites of replication have not been fully described. The isolation of an agent from a cat with spontaneous leukemia and transmission of the disease with cell-free preparations to newborn kittens presented an opportunity for an extensive eleotron mioroscopic examination of the feline leukemogenic agent.The agent apparently undergoes development by budding from the plasma or vacuolar membranes of infected host cells. The earliest stage of development is recognizable in thin section by a crescent-shaped electron-dense zone beneath the plasma membrane (Fig. 1a). This structure or bud enlarges progressively into a sphere which is resolvable into two concentric components and concomitantly causes a protrusion of the plasma membrane. Later stages are independent of the host cell proper. The immature forms (Fig. 1b), one recently detached from the plasma membrane, still maintain the internal morphology of the later stages of budding but is completely surrounded by a protein coat. The mature forms (Fig. 2) which develop by reorganization of the dense shells possess either a central electron-dense or central electron-lucent nucleoid. The difference between mature electron-lucent and immature forms appears to be an absence of the organized concentric shell in the former.

scholarly journals A genome-wide circular RNA transcriptome in Rat

2021 ◽  
Author(s):  
Disha Sharma ◽  
Paras Sehgal ◽  
Sridhar Sivasubbu ◽  
Vinod Scaria
Keyword(s):  
Developmental Stages ◽  
Donor Site ◽  
Model Organism ◽  
Circular Rna ◽  
Development Stage ◽  
Model Organisms ◽  
Circular Rnas ◽  
Tissue Samples ◽  
A Genome ◽  
The Difference

Abstract Circular RNAs are a novel class of non-coding RNAs that backsplice from 5' donor site and 3' acceptor sites to form a circular structure. A number of circRNAs have been discovered in model organisms including human, mouse, Drosophila, among other organisms. There are a few candidate-based studies on circular RNAs in rat, a well-studied model organism as well. A number of pipelines have been published to identify the back splice junctions for the discovery of circRNAs but studies comparing these tools have suggested that a combination of tools would be a better approach to identify high-confidence circular RNAs. The availability of a recent dataset of transcriptomes encompassing 11 tissues, 4 developmental stages and 2 genders motivated us to explore the landscape of circular RNAs in the organism in this context. In order to understand the difference among different pipelines, we employed 5 different combinations of tools to identify circular RNAs from the dataset. We compared the results of the different combination of tools/pipelines with respect to alignment, total number of circRNAs identified and read-coverage. In addition, we identified tissue-specific, development-stage specific and gender-specific circular RNAs and further independently validated 16 circRNA junctions out of 24 selected candidates in 5 tissue samples and estimated the quantitative expression of 5 circRNA candidates using real-time PCR and our analysis suggests 3 candidates as tissue-enriched. This study is one of the most comprehensive studies that provides a map of circular RNA transcriptome as well as to understand the difference among different computational pipelines in Rat.

Meristic and Morphometric Variation between the Endangered Acadian Whitefish, Coregonus huntsmani, and the Lake Whitefish, Coregonus clupeaformis, in the Canadian Maritime Provinces and the State of Maine, USA

1991 ◽  
Vol 48 (11) ◽  
pp. 2140-2151 ◽  
Author(s):  
Thomas A. Edge ◽  
Don E. McAllister ◽  
Sami U. Qadri
Keyword(s):  
Morphological Variation ◽  
Morphological Characteristics ◽  
Principal Component ◽  
The State ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Maritime Provinces ◽  
Morphometric Variation ◽  
Morphometric Characters ◽  
Adipose Fin

Principal component and discriminant function analyses of morphological variation between whitefish populations from the Canadian Maritime Provinces and the State of Maine, USA, clearly distinguished the Acadian whitefish, Coregonus huntsmani, from the lake whitefish species complex, Coregonus clupeaformis. Ten meristic and 44 morphometric characters were examined and the species were best discriminated by number of vertebrae (>97% separation) and mouth shape. Acadian whitefish had a terminal mouth and 64–67 [Formula: see text] vertebrae, while lake whitefish had a subterminal mouth and 58–64 [Formula: see text] vertebrae. Acadian whitefish were also characterized by having more lateral line scales (88–100, [Formula: see text] than lake whitefish (63–95, [Formula: see text], a shorter adipose to caudal fin length, a smaller adipose fin, and a longer pelvic axillary process than lake whitefish. Considerable morphological variation was found between lake whitefish populations examined although there was no morphological basis to recognize any lake whitefish population as taxonomically distinct. The Acadian whitefish has morphological characteristics of both subgenera Leucichthys and Coregonus; it could be important for understanding the evolution of coregonine fishes and its imminent extinction would represent a serious loss of genetic diversity.

Revised karyotypes and chromosome banding of coregonid fishes from the Laurentian Great Lakes

1996 ◽  
Vol 74 (2) ◽  
pp. 323-329 ◽  
Author(s):  
Ruth B. Phillips ◽  
Kent M. Reed ◽  
Petr Ráb
Keyword(s):  
Great Lakes ◽  
Chromosome Pair ◽  
Acrocentric Chromosome ◽  
Chromosome Morphology ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Chromosome Fusion ◽  
C Banding ◽  
The Difference ◽  
Submetacentric Pair

Karyotypes of lake whitefish, Coregonus clupeaformis, and various Great Lakes cisco species, lake herring or cisco, C. artedi, bloater, C. hoyi, blackfin cisco, C. nigripinnis, and shortjaw cisco, C. zenithicus, were analyzed using Giemsa staining, C-banding, silver staining, and Chromomycin A3 fluorescence. Coregonus clupeaformis had a karyotype (2n = 80, NF = 98) indistinguishable from that described for C. laveretus from Europe, with one pair of nuclear organizer regions (NORs) on the short arms of a small acrocentric chromosome pair and a second NOR on the short arms of another acrocentric chromosome pair. This species displayed a size polymorphism involving the heterochromatic short arm of the largest metacentric–submetacentric pair. All four cisco species had similar karyotypes (2n = 80, NF = 98), with the exception of some C. artedi from Lake Superior, which were heterozygous for a chromosome fusion involving the NOR chromosomes (2n = 79). One NOR was located pericentromerically on the long arm of the second largest acrocentric chromosome and a second NOR on the short arms of another acrocentric chromosome pair in several individuals. C-banding revealed that the difference in chromosome morphology between lake whitefish and the ciscoes probably resulted from amplification of heterochromatin on the short arms of one pair of large submetacentric–metacentric chromosomes.

Estimates of Lamprey-Induced Mortality in Whitefish, Coregonus clupeaformis

1980 ◽  
Vol 37 (11) ◽  
pp. 2146-2150 ◽  
Author(s):  
George R. Spangler ◽  
Douglas S. Robson ◽  
Henry A. Regier
Keyword(s):  
Attack Rate ◽  
Petromyzon Marinus ◽  
Late Summer ◽  
Lake Huron ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Fishing Season ◽  
The Difference

The seasonal rate of lamprey attack upon lake whitefish in Lake Huron is estimable as the proportion of recently wounded fish in the catch. The nonfatal lamprey attack rate is estimable from the accumulation of healed scars observed on a cohort of marked (tagged) fish sampled throughout the fishing season. The difference between these estimates is an estimate of the fatal lamprey attack coefficient. In northern Lake Huron, lamprey attacks on whitefish are most frequent during August to November. The fatal lamprey attack rate is greatest during late summer when a large proportion of attacks results in the death of the host. Approximately 75% of the lamprey attacks on whitefish are fatal during mid-June to mid-November.Key words: Lake Huron, Petromyzon marinus, lake whitefish, lamprey attack rate

Inheritance of Some Morphological Characteristics of Parental Lines in Mustard-Rape Hybrid

2020 ◽  
pp. 23-30
Keyword(s):  
First Generation ◽  
Agronomic Traits ◽  
Morphological Characteristics ◽  
Morphological Characters ◽  
Hybrid Plant ◽  
Distant Hybridization ◽  
Degree Of Dominance ◽  
Whole Plant ◽  
Row Width ◽  
The Difference

Distant hybridization is known to play an important role in expanding the gene pool of any crop. It is believed that the combination of different genomes in one nucleus, as a rule, is accompanied by the phenomenon of “genomic shock”, resulting in a variety of genetic and epigenetic changes. This provides a wealth of material for the selection of genotypes adapted to different environmental conditions. Interspecific hybrids in different combinations were obtained in the genus Brassica, however, until now, interest in distant hybridization in this genus has not died out, since such important crops as rapeseed and mustard demand an improvement of many important agronomic traits. The aim of this work was to study the degree of manifestation of morphological characters of a leaf, flower, and plant as a whole in the hybrid obtained by crossing of brown mustard of the variety Slavyanka and a collection specimen of spring rape. Seeds were sown in the spring of 2019 in a field with 30 cm row width. During the flowering period a number of morphological characters of a flower, leaf, and the whole plant were analyzed. Each parameter was evaluated with 10 plants. The degree of dominance in first-generation hybrid was calculated by the formula of Beil, Atkins (1965). The dominance coefficients were not determined in the case when the difference between the parental samples was insignificant. Differences between parental samples were determined by Student t-test. The level of heterosis was calculated according to the formula of Rasul et al (2002). In a mustard-rapeseed hybrid, the size of the leaves of the lower row was inherited by the type of rapeseed, which had larger leaves than mustard. The height of the hybrid plant was inherited by the type of mustard (hp = 1.32, Ht = 4.89%), and intermediate inheritance was observed for the length of the internodes (hp = -0.48). The size of the flower petals and sepals was inherited by the type of rapeseed, and significant heterosis was observed for the length of the pistil (Ht = 33.57%). The data obtained are of interest for understanding the interaction of genes of different genomes in the genus Brassica.

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