scholarly journals Genetic analysis of systematic mitochondrial heteroplasmy in rabbits.

Genetics ◽  
1994 ◽  
Vol 138 (2) ◽  
pp. 471-480 ◽  
Author(s):  
D Casane ◽  
N Dennebouy ◽  
H de Rochambeau ◽  
J C Mounolou ◽  
M Monnerot
Keyword(s):  
Mitochondrial Dna ◽  
Replication Origin ◽  
Molecular Diversity ◽  
Germ Line ◽  
Variable Number ◽  
The Other ◽  
Molecular Forms ◽  
Unusual Property ◽  
Mitochondrial Heteroplasmy ◽  
Selection For

Abstract One unusual property of rabbit mitochondrial DNA (mtDNA) is the existence of repeated 153-bp motifs in the vicinity of the replication origin of its H strand. Furthermore, every individual is heteroplasmic: it carries mtDNA molecules with a variable number of repeats. A systematic study of 8 females and their progeny has been devised to analyze mtDNA transmission through generations. The results suggest that three mechanisms are acting simultaneously. (1) Genetic drift in the germ line is revealed by the evolution of heteroplasmy when two major molecular forms are present in a female. (2) A high mutation rate (around 10(-2) per animal generation) generating molecular diversity, by deletion and addition of repeated units, is required to explain the observation of heteroplasmy in every individual. Moreover, the rates of mutation from the most frequent type to the other types are unequal. The deletion of one unit is more frequent than a deletion of two units, which is in turn more frequent than a deletion of three. (3) Selection for shorter molecules in somatic cells is probable. The frequency distribution of mtDNA types depends on the organ analyzed (kidney-spleen and liver vs. gonads).

SIMULATING THE MITOCHONDRIAL DNA BOTTLENECK

2000 ◽  
Vol 11 (07) ◽  
pp. 1297-1304 ◽  
Author(s):  
JAN P. RADOMSKI ◽  
S. MOSS DE OLIVEIRA
Keyword(s):  
Mitochondrial Dna ◽  
Host Cell ◽  
Probabilistic Model ◽  
Germ Line ◽  
Cell Generation ◽  
The Other ◽  
Deleterious Mutations ◽  
Selection Mechanism ◽  
Cell Reproduction ◽  
A Cell

A probabilistic model is proposed with dynamics which naturally leads to a bottleneck in the number of mitochondria transmitted from one host-cell generation to the other. We take into account deleterious mutations during the replication of mitochondria within a cell of a germ-line and introduce selection inside the cell reproduction mechanism. The bottleneck size strongly depends on the selection mechanism and on the maximum number of mitochondria per cell. We obtain that the smaller the maximum allowed number of mitochondria per cell during replication, the tighter the bottleneck. Such a result is in agreement with the fact that species producing small litters provide developing oocytes with a smaller number of mitochondria. This amplifies the differences among oocytes leading to competition and removal of inferior cells.

The Leptobrachium (Anura: Megophryidae) of the Langbian Plateau, southern Vietnam, with description of a new species

Zootaxa ◽  
2011 ◽  
Vol 2804 (1) ◽  
pp. 25 ◽  
Author(s):  
BRYAN L. STUART ◽  
JODI J. L. ROWLEY ◽  
DAO THI ANH TRAN ◽  
DUONG THI THUY LE ◽  
HUY DUC HOANG
Keyword(s):  
Mitochondrial Dna ◽  
New Species ◽  
Small Body ◽  
Original Description ◽  
The Other ◽  
Sexually Active ◽  
Small Body Size ◽  
Upper Lip ◽  
Southern Vietnam ◽  
A New Species

We sampled two forms of Leptobrachium in syntopy at the type locality of L. pullum at upper elevations on the Langbian Plateau, southern Vietnam. The two forms differed in morphology (primarily in coloration), mitochondrial DNA, and male advertisement calls. One form closely agrees with the type series of L. pullum (but not to its original description due to error), and the other is described as new. Leptobrachium leucops sp. nov. is distinguished from its congeners by having small body size (males with SVL 38.8–45.2), the upper one-third to one-half of iris white, a blue scleral arc, a dark venter, and sexually active males without spines on the upper lip. Leptobrachium pullum and L. mouhoti, a recently described species from low-elevation slopes of the Langbian Plateau in eastern Cambodia, are morphologically divergent but genetically similar, warranting further investigation into geographic variation in the red-eyed Leptobrachium of southern Indochina.

The effect of exposure to conspecifics on restlessness in the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King
Keyword(s):  
Habitat Quality ◽  
Parasitoid Wasp ◽  
Poor Quality ◽  
The Other ◽  
Dispersal Ability ◽  
Nasonia Vitripennis ◽  
Adult Females ◽  
Selection For ◽  
The Difference ◽  
Abundance And Distribution

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.

scholarly journals Replication Origin of Mitochondrial DNA in Insects

Genetics ◽  
2005 ◽  
Vol 171 (4) ◽  
pp. 1695-1705 ◽  
Author(s):  
Shigeru Saito ◽  
Koichiro Tamura ◽  
Tadashi Aotsuka
Keyword(s):  
Mitochondrial Dna ◽  
Replication Origin

Pannexin channels and their links to human disease

2014 ◽  
Vol 461 (3) ◽  
pp. 371-381 ◽  
Author(s):  
Silvia Penuela ◽  
Luke Harland ◽  
Jamie Simek ◽  
Dale W. Laird
Keyword(s):  
Infectious Diseases ◽  
Human Disease ◽  
Potential Role ◽  
Germ Line ◽  
Disease Onset ◽  
The Other ◽  
Present Review ◽  
Germ Line Mutations ◽  
Genes Encoding ◽  
Intracellular Compartments

In less than a decade, a small family of channel-forming glycoproteins, named pannexins, have captured the interest of many biologists, in large part due to their association with common diseases, ranging from cancers to neuropathies to infectious diseases. Although the pannexin family consists of only three members (Panx1, Panx2 and Panx3), one or more of these pannexins are expressed in virtually every mammalian organ, implicating their potential role in a diverse array of pathophysiologies. Panx1 is the most extensively studied, but features of this pannexin must be cautiously extrapolated to the other pannexins, as for example we now know that Panx2, unlike Panx1, exhibits unique properties such as a tendency to be retained within intracellular compartments. In the present review, we assess the biochemical and channel features of pannexins focusing on the literature which links these unique molecules to over a dozen diseases and syndromes. Although no germ-line mutations in genes encoding pannexins have been linked to any diseases, many cases have shown that high pannexin expression is associated with disease onset and/or progression. Disease may also occur, however, when pannexins are underexpressed, highlighting that pannexin expression must be exquisitely regulated. Finally, we discuss some of the most pressing questions and controversies in the pannexin field as the community seeks to uncover the full biological relevance of pannexins in healthy organs and during disease.

Tx1: a transposable element from Xenopus laevis with some unusual properties

1986 ◽  
Vol 6 (3) ◽  
pp. 933-941
Author(s):  
J E Garrett ◽  
D Carroll
Keyword(s):  
Xenopus Laevis ◽  
Germ Line ◽  
Variable Number ◽  
Target Site ◽  
Nucleotide Sequence Analysis ◽  
Chromosomal Locus ◽  
Stem Loop ◽  
Left Handed ◽  
Transposable Genetic Elements

A family of transposable genetic elements in the genome of the frog, Xenopus laevis, is described. They are designated Tx1. Transposability of the elements was deduced by characterization of a chromosomal locus which is polymorphic for the presence or absence of a Tx1 element. Nucleotide sequence analysis suggested that Tx1 elements show target site specificity, as they are inserted at the pentanucleotide TTTAA in all four cases that were examined. The elements appear to have 19-base-pair (bp) inverted terminal repeats, and they are flanked by 4-bp target duplications (TTAA), although the possibility that they do not create target site duplications is discussed. Tx1 elements have several unusual characteristics: the central portion of each element is comprised of a variable number of two types of 393-bp repeating units; the rightmost 1,000 bp of the element contains separate regions potentially capable of forming bends, left-handed Z-form DNA, and alternative stem-loop structures. Comparisons among single frogs suggest that germ line transposition is relatively infrequent and that variations in numbers of internal repeats accumulate quite slowly at any locus.

scholarly journals Evaluation of Resistance Development in Bemisia tabaci Genn. (Homoptera: Aleyrodidae) in Cotton against Different Insecticides

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 996
Author(s):  
Muhammad Zaryab Khalid ◽  
Sohail Ahmed ◽  
Ibrahim Al-ashkar ◽  
Ayman EL Sabagh ◽  
Liyun Liu ◽  
...  
Keyword(s):  
Bemisia Tabaci ◽  
The Other ◽  
Resistance Development ◽  
Susceptible Population ◽  
Low Level ◽  
Development Of Resistance ◽  
Major Pest ◽  
Selection For ◽  
High Level ◽  
Very High

Cotton is a major crop of Pakistan, and Bemisia tabaci (Homoptera: Aleyrodidae) is a major pest of cotton. Due to the unwise and indiscriminate use of insecticides, resistance develops more readily in the whitefly. The present study was conducted to evaluate the resistance development in the whitefly against the different insecticides that are still in use. For this purpose, the whitefly population was selected with five concentrations of each insecticide, for five generations. At G1, compared with the laboratory susceptible population, a very low level of resistance was observed against bifenthrin, cypermethrin, acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin with a resistance ratio of 3-fold, 2-fold, 1-fold, 4-fold, 3-fold, 3-fold, 3-fold, and 3-fold, respectively. However, the selection for five generations increased the resistance to a very high level against buprofezin (127-fold), and to a high level against imidacloprid (86-fold) compared with the laboratory susceptible population. While, a moderate level of resistance was observed against cypermethrin (34-fold), thiamethoxam (34-fold), nitenpyram (30-fold), chlorfenapyr (29-fold), and acetamiprid (21-fold). On the other hand, the resistance was low against bifenthrin (18-fold) after selection for five generations. A very low level of resistance against the field population of B. tabaci, at G1, showed that these insecticides are still effective, and thus can be used under the field conditions for the management of B. tabaci. However, the proper rotation of insecticides among different groups can help to reduce the development of resistance against insecticides.

scholarly journals Henricia djakonovisp. nov. (Echinodermata, Echinasteridae): a new sea star species from the Sea of Japan

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2863 ◽  
Author(s):  
Anton Chichvarkhin
Keyword(s):  
New Species ◽  
Sea Of Japan ◽  
Common Species ◽  
Sympatric Species ◽  
Variable Number ◽  
The Other ◽  
The Sea Of Japan ◽  
Sea Star ◽  
The Pacific ◽  
Russian Waters

A new sea star species,H. djakonovisp.n., was discovered in Rudnaya Bay in the Sea of Japan. This is a sympatric species of the well-known and common speciesHenricia pseudoleviusculaDjakonov, 1958. Both species are similar in body size and proportions, shape of skeletal plates, and life coloration, which distinguishes them from the otherHenriciaspecies inhabiting the Sea of Japan. Nevertheless, these species can be distinguished by their abactinal spines: in both species, they are short and barrel-like, but the new species is the onlyHenriciaspecies in Russian waters of the Pacific that possesses such spines with a massive, smooth, bullet-like tip. The spines inH. pseudoleviusculaare crowned with a variable number of well-developed thorns. About half (<50%) of the abactinal pseudopaxillae in the new species are oval, not crescent-shaped as inH. pseudoleviuscula.

scholarly journals Development of bioactive/active additives based on essential oils: A review

2020 ◽  
Vol 3 (4) ◽  
pp. 60-67
Author(s):  
Jessica Alarcón-Moyano ◽  
◽  
Silvia Matiacevich ◽  
Keyword(s):  
Medicinal Plants ◽  
Essential Oil ◽  
Essential Oils ◽  
Freeze Drying ◽  
The Other ◽  
Wall Material ◽  
Oil Oxidation ◽  
Active Additive ◽  
Wall Materials ◽  
Selection For

The use of bioactive/active additives has been increasing in recent years, especially those derived from medicinal plants such as essential oils. However, due to essential oil oxidation it is necessary to protect it by encapsulation techniques such as: emulsion, spray- and/or freeze-drying as the most economical techniques. On the other hand, an important factor is to determine the appropriate wall material to obtain a prolonged or controlled release in the food or in the organism. Therefore, several factors affect the release of the compounds such as the type, amount of wall material and/or combination of wall materials. Therefore, the knowledge of all the aforementioned factors is important in order to make an adequate selection for the development of a bioactive/active additive based on essential oils.

SACCHAROMYCES CEREVISIAE PETITE MITOCHONDRIAL DNA OF SUPPRESSIVE AND NEUTRAL HAPLOIDS AND OF [rho−] DIPLOIDS OBTAINED FROM CROSSING [rho+] TO A NEUTRAL PETITE

1975 ◽  
Vol 17 (3) ◽  
pp. 381-389 ◽  
Author(s):  
A. J. Robertson ◽  
N. T. Bech-Hansen ◽  
G. H. Rank
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Ethidium Bromide ◽  
Buoyant Density ◽  
Unusual Property ◽  
Mating Reaction

An unusual property of GR25a [rho+] was the production of 20 to 30 percent [rho−] zygote colonies when crossed to a tester strain lacking mitochondrial DNA. Spontaneous [rho−] isolates of GR25a [rho+] were observed to be highly suppressive and to contain mitochondrial DNA of a parental buoyant density (1.685 g/cm3). Three ethidium bromide induced neutral petites of GR25a [rho+] did not have detectable mitochondrial DNA and were neutral in crosses to [rho+] strains. Seven [rho−] zygote colony isolates obtained from crossing GR25a [rho+] to a neutral petite were shown to contain abnormal mitochondrial DNA. Six zygote colony isolates had mitochondrial DNA of a buoyant density less than, or equal to, GR25a (1.682–1.685 g/cm3), whereas one isolate had a buoyant density greater than GR25a (1.688 g/cm3). It was suggested that abnormal mitochondrial DNA is generated during the mating reaction.

Sign in / Sign up

Export Citation Format

Share Document