Heterochromatinization, chromatin elimination and haploidization in the parahaploid mite Metaseiulus occidentalis (Nesbitt) (Acarina: Phytoseiidae)

Chromosoma ◽  
1980 ◽  
Vol 77 (3) ◽  
pp. 263-276 ◽  
Author(s):  
Walter A. Nelson-Rees ◽  
Marjorie A. Hoy ◽  
R. T. Roush
Keyword(s):  
Metaseiulus Occidentalis ◽  
Chromatin Elimination

scholarly journals Boon and Bane of DNA Double-Strand Breaks

2021 ◽  
Vol 22 (10) ◽  
pp. 5171
Author(s):  
Ingo Schubert
Keyword(s):  
Negative Impact ◽  
Biological Effects ◽  
Double Strand Breaks ◽  
Immunoglobulin Gene ◽  
Dna Double Strand Breaks ◽  
Endogenous Factors ◽  
Strand Breaks ◽  
Chromatin Elimination ◽  
Evolutionary Consequences ◽  
Cell Lethality

DNA double-strand breaks (DSBs), interrupting the genetic information, are elicited by various environmental and endogenous factors. They bear the risk of cell lethality and, if mis-repaired, of deleterious mutation. This negative impact is contrasted by several evolutionary achievements for DSB processing that help maintaining stable inheritance (correct repair, meiotic cross-over) and even drive adaptation (immunoglobulin gene recombination), differentiation (chromatin elimination) and speciation by creating new genetic diversity via DSB mis-repair. Targeted DSBs play a role in genome editing for research, breeding and therapy purposes. Here, I survey possible causes, biological effects and evolutionary consequences of DSBs, mainly for students and outsiders.

Chromatin Elimination Induced by the B Chromosome of Maize

1973 ◽  
Vol 64 (1) ◽  
pp. 13-18 ◽  
Author(s):  
M. M. RHOADES ◽  
ELLEN DEMPSEY
Keyword(s):  
B Chromosome ◽  
Chromatin Elimination

scholarly journals I8-arachnotocin–an arthropod-derived G protein-biased ligand of the human vasopressin V2 receptor

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Leopold Duerrauer ◽  
Edin Muratspahić ◽  
Jasmin Gattringer ◽  
Peter Keov ◽  
Helen C. Mendel ◽  
...  
Keyword(s):  
G Protein ◽  
Partial Agonist ◽  
Receptor Subtypes ◽  
Signaling System ◽  
Pharmacological Characterization ◽  
Metaseiulus Occidentalis ◽  
Physiological Relevance ◽  
V2 Receptor ◽  
Second Messenger Signaling ◽  
The Individual

AbstractThe neuropeptides oxytocin (OT) and vasopressin (VP) and their G protein-coupled receptors OTR, V1aR, V1bR, and V2R form an important and widely-distributed neuroendocrine signaling system. In mammals, this signaling system regulates water homeostasis, blood pressure, reproduction, as well as social behaviors such as pair bonding, trust and aggression. There exists high demand for ligands with differing pharmacological profiles to study the physiological and pathological functions of the individual receptor subtypes. Here, we present the pharmacological characterization of an arthropod (Metaseiulus occidentalis) OT/VP-like nonapeptide across the human OT/VP receptors. I8-arachnotocin is a full agonist with respect to second messenger signaling at human V2R (EC50 34 nM) and V1bR (EC50 1.2 µM), a partial agonist at OTR (EC50 790 nM), and a competitive antagonist at V1aR [pA2 6.25 (558 nM)]. Intriguingly, I8-arachnotocin activated the Gαs pathway of V2R without recruiting either β-arrestin-1 or β-arrestin-2. I8-arachnotocin might thus be a novel pharmacological tool to study the (patho)physiological relevance of β-arrestin-1 or -2 recruitment to the V2R. These findings furthermore highlight arthropods as a novel, vast and untapped source for the discovery of novel pharmacological probes and potential drug leads targeting neurohormone receptors.

scholarly journals Bacterial Symbionts of the Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae)

2010 ◽  
Vol 76 (6) ◽  
pp. 1740-1745 ◽  
Author(s):  
Ming Tang ◽  
Lu Lv ◽  
Shengli Jing ◽  
Lili Zhu ◽  
Guangcun He
Keyword(s):  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Rrna Gene ◽  
Rice Varieties ◽  
Ovipositor Sheath ◽  
Operational Taxonomic Units ◽  
Metaseiulus Occidentalis ◽  
High Virulence ◽  
Gene Libraries

ABSTRACT The brown planthopper (Nilaparvata lugens Stål), the most destructive pest of rice, has been identified, including biotypes with high virulence towards previously resistant rice varieties. There have also been many reports of a yeast-like symbiont of N. lugens, but little is known about the bacterial microbes. In this study, we examined the bacterial microbes in N. lugens and identified a total of 18 operational taxonomic units (OTUs) representing four phyla (Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes) by sequencing and analyzing 16S rRNA gene libraries obtained from three populations of N. lugens, which were maintained on the rice varieties TN1, Mudgo, and ASD7. Several of the OTUs were similar to previously reported secondary symbionts of other insects, including an endosymbiont of the psyllid Glycapsis brimblecombei, an Asaia sp. found in the mosquito Anopheles stephensi, and Wolbachia, found in the mite Metaseiulus occidentalis. However, the species and numbers of the detected OTUs differed substantially among the N. lugens populations. Further, in situ hybridization analysis using digoxigenin-labeled probes indicated that OTU 1 was located in hypogastrium tissues near the ovipositor and ovary in biotype 1 insects, while OTU 2 was located in the front of the ovipositor sheath in biotype 2 insects. In addition, masses of bacterium-like organisms were observed in the tubes of salivary sheaths in rice plant tissues that the insects had fed upon. The results provide indications of the diversity of the bacterial microbes harbored by the brown planthopper and of possible associations between specific bacterial microbes and biotypes of N. lugens.

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