scholarly journals Seasonal changes in body size and oil sac volume of three planktonic copepods, Paracalanus parvus (Claus, 1863), Pseudocalanus newmani Frost, 1989 and Oithona similis Claus, 1866, in a temperate embayment: what controls their seasonality?

Crustaceana ◽  
2014 ◽  
Vol 87 (3) ◽  
pp. 364-375 ◽  
Author(s):  
Daichi Arima ◽  
Atsushi Yamaguchi ◽  
Yoshiyuki Abe ◽  
Kohei Matsuno ◽  
Rui Saito ◽  
...  
Keyword(s):  
Body Size ◽  
Seasonal Changes ◽  
Primary Energy ◽  
Specific Pattern ◽  
Peak Period ◽  
Oithona Similis ◽  
Warm Summer ◽  
Cold Spring ◽  
Species Specific ◽  
Paracalanus Parvus

Seasonal changes in body size (prosome length: PL) and oil sac volume (OSV) of the three most numerically abundant copepods in Ishikari Bay, northern Sea of Japan, Paracalanus parvus (Claus, 1863), Pseudocalanus newmani Frost, 1989 and Oithona similis Claus, 1866, were studied using monthly samples collected through vertical hauls of a 100-μm mesh NORPAC net from March, 2001 to May, 2002. Seasonal changes in PL were common for the three species and were more pronounced during a cold spring. PL was negatively correlated with temperature, and this relationship was described well using the Bělehrádek equation. Seasonal changes in OSV exhibited a species-specific pattern, i.e., OSV was greater during a warm summer for P. parvus and was greater during a cold spring for P. newmani and O. similis. The OSV peak period corresponded with the optimal thermal season of each species. The relative OSV to prosome volume of the small copepods (0.6-0.8%) was substantially lower than that of the large copepods (20-32%). These facts suggest that the oil sac of small copepods is not used for overwintering or diapauses or during periods of food scarcity, but is instead used as the primary energy source for reproduction, which occurs during the optimum thermal season of each species.

LINE-1 distribution in six rodent genomes follow a species-specific pattern

2016 ◽  
Vol 95 (1) ◽  
pp. 21-33 ◽  
Author(s):  
A. VIEIRA-DA-SILVA ◽  
F. ADEGA ◽  
H. GUEDES-PINTO ◽  
R. CHAVES
Keyword(s):  
Specific Pattern ◽  
Species Specific

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

Morphogenetic Events in Normal and Synchronously Dividing Tetrahymena

Development ◽  
1959 ◽  
Vol 7 (2) ◽  
pp. 241-256
Author(s):  
Norman E. Williams ◽  
Otto H. Scherbaum
Keyword(s):  
Daughter Cell ◽  
Tetrahymena Pyriformis ◽  
Building Blocks ◽  
Specific Pattern ◽  
Central Position ◽  
Parent Cell ◽  
Ciliated Protozoan ◽  
Mass Cultures ◽  
Synchronous Cell ◽  
Species Specific

Synchronous cell-division has been induced in mass cultures of the small ciliated protozoan Tetrahymena pyriformis (Scherbaum & Zeuthen, 1954). While it is known that cells grow in a characteristic way during the synchronizing treatment the effect on the morphogenetic events associated with the cell cycle is not clear. Studies in ciliate morphogenesis generally have established the central position of the ciliary basal body, or kinetosome, in developmental processes. The kinetosomes are believed to be self-duplicating structures, the kinetosomal population of a daughter cell arising directly by kinetosomal reproduction in the parent cell. The species-specific pattern of the ectoplasmic cortex is largely a matter of the distribution of kinetosomes. Further, the kinetosomes appear to function either as building blocks or ‘local organizers’ in most, if not all, structural syntheses occurring in the cortex, i.e. in the production cilia, cirri, membranelles, trichocysts, and other ciliate structures (see Weisz, 1954).

scholarly journals Can snakes use yolk reserves to maximize body size at hatching?

2018 ◽  
Vol 65 (6) ◽  
pp. 627-631 ◽  
Author(s):  
Yan-Fu Qu ◽  
Shu-Zhan Zhao ◽  
Xu-Fei Jiang ◽  
Long-Hui Lin ◽  
Xiang Ji
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Tail Length ◽  
Linear Size ◽  
Egg Mass ◽  
Fat Bodies ◽  
Free Body ◽  
Species Specific ◽  
Naja Atra

Abstract We experimentally miniaturized freshly laid eggs of the Chinese cobra Naja atra (Elapidae) by removing ∼10% and ∼20% of original yolk. We tested if yolk-reduced eggs would produce 1) normal-sized hatchlings with invariant yolk-free body mass (and thus invariant linear size) but dramatically reduced or even completely depleted residual yolk, 2) smaller hatchlings with normal-sized residual yolk but reduced yolk-free body mass, or 3) smaller hatchlings of which both yolk-free body mass and residual yolk are proportionally reduced. Yolk quantity affected hatchling linear size (both snout-vent length and tail length) and body mass. However, changes in yolk quantity did not affect incubation length or any hatchling trait examined after accounting for egg mass at laying (for control and sham-manipulated eggs) or after yolk removal (for manipulated eggs). Specifically, yolk-reduced eggs produced hatchlings of which all major components (carcass, residual yolk, and fat bodies) were scaled down proportionally. We show that snakes cannot use yolk reserves to maximize their body size at hatching. Furthermore, our data also suggest that the partitioning of yolk in embryonic snakes is species-specific.

scholarly journals Risk Factors for Development of Canine and Human Osteosarcoma: A Comparative Review

2019 ◽  
Vol 6 (2) ◽  
pp. 48 ◽  
Author(s):  
Kelly M. Makielski ◽  
Lauren J. Mills ◽  
Aaron L. Sarver ◽  
Michael S. Henson ◽  
Logan G. Spector ◽  
...  
Keyword(s):  
Risk Factors ◽  
Body Size ◽  
Bone Cancer ◽  
Domestic Dogs ◽  
Comparative Approach ◽  
Important Species ◽  
Human Osteosarcoma ◽  
Comparative Review ◽  
Cellular Replication ◽  
Species Specific

Osteosarcoma is the most common primary tumor of bone. Osteosarcomas are rare in humans, but occur more commonly in dogs. A comparative approach to studying osteosarcoma has highlighted many clinical and biologic aspects of the disease that are similar between dogs and humans; however, important species-specific differences are becoming increasingly recognized. In this review, we describe risk factors for the development of osteosarcoma in dogs and humans, including height and body size, genetics, and conditions that increase turnover of bone-forming cells, underscoring the concept that stochastic mutational events associated with cellular replication are likely to be the major molecular drivers of this disease. We also discuss adaptive, cancer-protective traits that have evolved in large, long-lived mammals, and how increasing size and longevity in the absence of natural selection can account for the elevated bone cancer risk in modern domestic dogs.

scholarly journals Origins and Evolutionary Patterns of the 1.688 Satellite DNA Family in Drosophila Phylogeny

2020 ◽  
Vol 10 (11) ◽  
pp. 4129-4146
Author(s):  
Leonardo G. de Lima ◽  
Stacey L. Hanlon ◽  
Jennifer L. Gerton
Keyword(s):  
Repetitive Sequences ◽  
Specific Pattern ◽  
Evolutionary Patterns ◽  
Satellite Dnas ◽  
Evolutionary Pattern ◽  
Functional Roles ◽  
Drosophila Phylogeny ◽  
Species Specific ◽  
Future Work ◽  
Eukaryotic Genomes

Satellite DNAs (satDNAs) are a ubiquitous feature of eukaryotic genomes and are usually the major components of constitutive heterochromatin. The 1.688 satDNA, also known as the 359 bp satellite, is one of the most abundant repetitive sequences in Drosophila melanogaster and has been linked to several different biological functions. We investigated the presence and evolution of the 1.688 satDNA in 16 Drosophila genomes. We find that the 1.688 satDNA family is much more ancient than previously appreciated, being shared among part of the melanogaster group that diverged from a common ancestor ∼27 Mya. We found that the 1.688 satDNA family has two major subfamilies spread throughout Drosophila phylogeny (∼360 bp and ∼190 bp). Phylogenetic analysis of ∼10,000 repeats extracted from 14 of the species revealed that the 1.688 satDNA family is present within heterochromatin and euchromatin. A high number of euchromatic repeats are gene proximal, suggesting the potential for local gene regulation. Notably, heterochromatic copies display concerted evolution and a species-specific pattern, whereas euchromatic repeats display a more typical evolutionary pattern, suggesting that chromatin domains may influence the evolution of these sequences. Overall, our data indicate the 1.688 satDNA as the most perduring satDNA family described in Drosophila phylogeny to date. Our study provides a strong foundation for future work on the functional roles of 1.688 satDNA across many Drosophila species.

scholarly journals Identification and susceptibility of clinical isolates of Candida spp. to killer toxins

2018 ◽  
Vol 78 (4) ◽  
pp. 742-749
Author(s):  
E. Robledo-Leal ◽  
L. G. Rivera-Morales ◽  
M. P. Sangorrín ◽  
G. M. González ◽  
G. Ramos-Alfano ◽  
...  
Keyword(s):  
Specific Pattern ◽  
Pcr Analysis ◽  
Its2 Region ◽  
Candida Spp ◽  
5.8S Rdna ◽  
Killer Toxins ◽  
Killer Yeasts ◽  
Invasive Infections ◽  
Pichia Kluyveri ◽  
Species Specific

Abstract Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp.

scholarly journals Serum Complement Sensitivity as a Key Factor in Lyme Disease Ecology

1998 ◽  
Vol 66 (3) ◽  
pp. 1248-1251 ◽  
Author(s):  
Klaus Kurtenbach ◽  
Henna-Sisko Sewell ◽  
Nick H. Ogden ◽  
Sarah E. Randolph ◽  
Patricia A. Nuttall
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Lyme Borreliosis ◽  
Disease Ecology ◽  
Specific Pattern ◽  
Serum Complement ◽  
Key Factor ◽  
Species Specific

ABSTRACT The sensitivity of Borrelia burgdorferi sensu lato to animal sera was analyzed. Complement-mediated borreliacidal effects were observed with particular combinations of host serum andBorrelia genospecies. The species-specific pattern of viability and/or lysis is highly consistent with the pattern of reservoir competence of hosts for B. burgdorferi sensu lato, suggesting a key role of complement in the global ecology of Lyme borreliosis.

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