Alterations in Development, Behavior, and Physiology inDrosophila Larva That Have Reduced Ecdysone Production

We investigated behavior, physiology, sensitivity to exogenous application of ecdysone, and nerve terminal structure for differences between the reduced ecdysone genotype, ecd 1 /ecd 1, and wild-type control ecd 1 /TM6Banimals during the early and late third instars when raised at 25°C. The ecd 1 mutants were able to survive through larval development and form pupae. However, the results demonstrate that the time to pupation is lengthened by about 50 h for the ecd 1 /ecd 1 as compared with the wild-type control siblings. In addition to the lengthened larval cycle in the mutant, ecd 1 /ecd 1animals, they also display behavioral differences as compared with controls. The rate of body wall contraction and mouth hook movements are reduced in the early third instar of ecd 1 /ecd 1 as compared with controls. The physiological measure of excitatory junction potential amplitude for the combined Is and Ib terminals did not reveal any differences among the two genotypes during the early third instar but the synaptic strength is reduced in the late third instars for controls. Application of exogenous ecdysone is still effective during the late third instar for the ecd 1 /ecd 1 but not the controls. This suggests that endogenous production of ecdysone have already taken place in the wild-type but not the ecd 1 /ecd 1larvae, thus the rapid nongenomic responses could still be observed in the late third ecd 1 /ecd 1larvae. Structurally the number of varicosities and the terminal length showed significant differences between ecd 1 /ecd 1 and the wild-type ecd 1 /TM6B genotype in the late third instars.

Download Full-text

Characterization of gamma irradiation-induced mutations in Arabidopsis mutants deficient in non-homologous end joining

Journal of Radiation Research ◽

10.1093/jrr/rraa059 ◽

2020 ◽

Vol 61 (5) ◽

pp. 639-647

Author(s):

Yan Du ◽

Yoshihiro Hase ◽

Katsuya Satoh ◽

Naoya Shikazono

Keyword(s):

Gamma Rays ◽

Wild Type ◽

End Joining ◽

Complex Type ◽

Single Base ◽

In The Wild ◽

Non Homologous End Joining ◽

Dna Ends ◽

Wild Type Control

Abstract To investigate the involvement of the non-homologous end joining (NHEJ) pathway in plant mutagenesis by ionizing radiation, we conducted a genome-wide characterization of the mutations induced by gamma rays in NHEJ-deficient Arabidopsis mutants (AtKu70−/− and AtLig4−/−). Although both mutants were more sensitive to gamma rays than the wild-type control, the AtKu70−/− mutant was slightly more sensitive than the AtLig4−/− mutant. Single-base substitutions (SBSs) were the predominant mutations in the wild-type control, whereas deletions (≥2 bp) and complex-type mutations [i.e. more than two SBSs or short insertion and deletions (InDels) separated by fewer than 10 bp] were frequently induced in the mutants. Single-base deletions were the most frequent deletions in the wild-type control, whereas the most common deletions in the mutants were 11–30 bp. The apparent microhomology at the rejoined sites of deletions peaked at 2 bp in the wild-type control, but was 3–4 bp in the mutants. This suggests the involvement of alternative end joining and single-strand annealing pathways involving increased microhomology for rejoining DNA ends. Complex-type mutations comprising short InDels were frequently detected in the mutants, but not in the wild-type control. Accordingly, NHEJ is more precise than the backup pathways, and is the main pathway for rejoining the broken DNA ends induced by ionizing radiation in plants.

Download Full-text

Estrogen receptor-α mediates estrogen-inducible abnormalities in the developing penis

Reproduction ◽

10.1530/rep-06-0326 ◽

2007 ◽

Vol 133 (5) ◽

pp. 1057-1067 ◽

Cited By ~ 17

Author(s):

H O Goyal ◽

T D Braden ◽

P S Cooke ◽

M A Szewczykowski ◽

C S Williams ◽

...

Keyword(s):

Estrogen Receptor ◽

Levator Ani ◽

Estrogen Receptor Α ◽

Control Group ◽

Wild Type ◽

Penile Length ◽

In The Wild ◽

Os Penis ◽

Harmful Effects ◽

Wild Type Control

Previously, we reported an association between estrogen receptor-α (ERα) upregulation and detrimental effects of neonatal diethylstilbestrol (DES) exposure in the rat penis. The objective of this study was to employ the ERα knockout (ERαKO) mouse model to test the hypothesis that ERα mediates DES effects in the developing penis. ERαKO and wild-type C57BL/6 mice received oil or DES at a dose of 0.2 μg/pup per day (0.1 mg/kg) on alternate days from postnatal days 2 to 12. Fertility was tested at 80–240 days of age and tissues were examined at 96–255 days of age. DES caused malformation of the os penis, significant reductions in penile length, diameter, and weight, accumulation of fat cells in the corpora cavernosa penis, and significant reductions in weight of the bulbospongiosus and levator ani muscles in wild-type mice. Conversely, ERαKO mice treated with DES developed none of the above abnormalities. While nine out of ten male mice sired pups in the wild-type/control group, none did in the wild-type/DES group. ERαKO mice, despite normal penile development, are inherently infertile. Both plasma and intratesticular testosterone levels were unaltered in the DES-treated wild-type or DES-treated ERαKO mice when compared with controls, although testosterone concentration was much higher in the ERαKO mice. Hence, the resistance of ERαKO mice to developing penile abnormalities provides unequivocal evidence of an obligatory role for ERα in mediating the harmful effects of neonatal DES exposure in the developing penis.

Download Full-text

Engineering of Primary Carbon Metabolism for Improved Antibiotic Production in Streptomyces lividans

Applied and Environmental Microbiology ◽

10.1128/aem.68.10.4731-4739.2002 ◽

2002 ◽

Vol 68 (10) ◽

pp. 4731-4739 ◽

Cited By ~ 51

Author(s):

Michael J. Butler ◽

Per Bruheim ◽

Srdjan Jovetic ◽

Flavia Marinelli ◽

Pieter W. Postma ◽

...

Keyword(s):

Antibiotic Production ◽

Streptomyces Lividans ◽

Pentose Phosphate ◽

Antibiotic Biosynthesis ◽

Wild Type ◽

In The Wild ◽

Commercially Important ◽

Biochemical Product ◽

Glucose 6 Phosphate Dehydrogenase ◽

Wild Type Control

ABSTRACT Deletions were made in Streptomyces lividans in either of two genes (zwf1 and zwf2) encoding isozymes of glucose-6-phosphate dehydrogenase, the first enzyme in the oxidative pentose phosphate pathway (PPP). Each mutation reduced the level of Zwf activity to approximately one-half that observed in the wild-type strain. When the mutants were transformed with multicopy plasmids carrying the pathway-specific transcriptional activator genes for either the actinorhodin (ACT) or undecylprodigiosin (RED) biosynthetic pathway, they produced higher levels of antibiotic than the corresponding wild-type control strains. The presumed lower flux of carbon through the PPP in each of the Δzwf mutants may allow more efficient glucose utilization via glycolysis, resulting in higher levels of antibiotic production. This appears to occur without lowering the concentration of NADPH (the major biochemical product of the oxidative PPP activity) to a level that would limit antibiotic biosynthesis. Consistent with this hypothesis, deletion of the gene (devB) encoding the enzyme that catalyzes the next step in the oxidative PPP (6-phosphogluconolactonase) also resulted in increased antibiotic production. However, deletion of both zwf genes from the devB mutant resulted in reduced levels of ACT and RED production, suggesting that some of the NADPH made by the PPP is utilized, directly or indirectly, for antibiotic biosynthesis. Although applied here to the model antibiotics ACT and RED, such mutations may prove to be useful for improving the yield of commercially important secondary metabolites.

Download Full-text

Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160996 ◽

1990 ◽

Vol 48 (3) ◽

pp. 688-689

Author(s):

Thecan Caesar-Ton That ◽

Lynn Epstein

Keyword(s):

Freeze Substitution ◽

Uranyl Acetate ◽

Wild Type ◽

Nectria Haematococca ◽

Fruit Extract ◽

Dialysis Tubing ◽

Tube Emergence ◽

Contrast Microscopy ◽

In The Wild ◽

Freeze Damage

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.

Download Full-text

Rad51-Independent Interchromosomal Double-Strand Break Repair by Gene Conversion Requires Rad52 but Not Rad55, Rad57, or Dmc1

Molecular and Cellular Biology ◽

10.1128/mcb.00524-07 ◽

2007 ◽

Vol 28 (3) ◽

pp. 897-906 ◽

Cited By ~ 21

Author(s):

Thomas J. Pohl ◽

Jac A. Nickoloff

Keyword(s):

Gene Conversion ◽

Strand Break ◽

Double Strand Break ◽

Single Strand ◽

Homology Search ◽

Wild Type ◽

Dsb Repair ◽

Single Strand Annealing ◽

In The Wild ◽

Break Induced Replication

ABSTRACT Homologous recombination (HR) is critical for DNA double-strand break (DSB) repair and genome stabilization. In yeast, HR is catalyzed by the Rad51 strand transferase and its “mediators,” including the Rad52 single-strand DNA-annealing protein, two Rad51 paralogs (Rad55 and Rad57), and Rad54. A Rad51 homolog, Dmc1, is important for meiotic HR. In wild-type cells, most DSB repair results in gene conversion, a conservative HR outcome. Because Rad51 plays a central role in the homology search and strand invasion steps, DSBs either are not repaired or are repaired by nonconservative single-strand annealing or break-induced replication mechanisms in rad51Δ mutants. Although DSB repair by gene conversion in the absence of Rad51 has been reported for ectopic HR events (e.g., inverted repeats or between plasmids), Rad51 has been thought to be essential for DSB repair by conservative interchromosomal (allelic) gene conversion. Here, we demonstrate that DSBs stimulate gene conversion between homologous chromosomes (allelic conversion) by >30-fold in a rad51Δ mutant. We show that Rad51-independent allelic conversion and break-induced replication occur independently of Rad55, Rad57, and Dmc1 but require Rad52. Unlike DSB-induced events, spontaneous allelic conversion was detected in both rad51Δ and rad52Δ mutants, but not in a rad51Δ rad52Δ double mutant. The frequencies of crossovers associated with DSB-induced gene conversion were similar in the wild type and the rad51Δ mutant, but discontinuous conversion tracts were fivefold more frequent and tract lengths were more widely distributed in the rad51Δ mutant, indicating that heteroduplex DNA has an altered structure, or is processed differently, in the absence of Rad51.

Download Full-text

Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.2.383 ◽

1996 ◽

Vol 142 (2) ◽

pp. 383-391 ◽

Cited By ~ 2

Author(s):

Yasumasa Tsukamoto ◽

Jun-ichi Kato ◽

Hideo Ikeda

Keyword(s):

Saccharomyces Cerevisiae ◽

Quantitative Analysis ◽

Structural Analysis ◽

Recombination Rate ◽

Type Strain ◽

Negative Selection ◽

Wild Type Strain ◽

Illegitimate Recombination ◽

Wild Type ◽

In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

Download Full-text

Transcriptome Analysis Provides Insights into the Mechanism of Astaxanthin Enrichment in a Mutant of the Ridgetail White Prawn Exopalaemon carinicauda

Genes ◽

10.3390/genes12050618 ◽

2021 ◽

Vol 12 (5) ◽

pp. 618

Author(s):

Yue Jin ◽

Shihao Li ◽

Yang Yu ◽

Chengsong Zhang ◽

Xiaojun Zhang ◽

...

Keyword(s):

Transcriptome Analysis ◽

Underlying Mechanism ◽

Biological Processes ◽

Wild Type ◽

Expression Levels ◽

In The Wild ◽

Cuticle Proteins ◽

Apolipoprotein D ◽

High Level ◽

Lower Expression

A mutant of the ridgetail white prawn, which exhibited rare orange-red body color with a higher level of free astaxanthin (ASTX) concentration than that in the wild-type prawn, was obtained in our lab. In order to understand the underlying mechanism for the existence of a high level of free astaxanthin, transcriptome analysis was performed to identify the differentially expressed genes (DEGs) between the mutant and wild-type prawns. A total of 78,224 unigenes were obtained, and 1863 were identified as DEGs, in which 902 unigenes showed higher expression levels, while 961 unigenes presented lower expression levels in the mutant in comparison with the wild-type prawns. Based on Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis, as well as further investigation of annotated DEGs, we found that the biological processes related to astaxanthin binding, transport, and metabolism presented significant differences between the mutant and the wild-type prawns. Some genes related to these processes, including crustacyanin, apolipoprotein D (ApoD), cathepsin, and cuticle proteins, were identified as DEGs between the two types of prawns. These data may provide important information for us to understand the molecular mechanism of the existence of a high level of free astaxanthin in the prawn.

Download Full-text

cot1: A Regulator of Arabidopsis Trichome Initiation

Genetics ◽

10.1093/genetics/149.2.565 ◽

1998 ◽

Vol 149 (2) ◽

pp. 565-577

Author(s):

Daniel B Szymanski ◽

Daniel A Klis ◽

John C Larkin ◽

M David Marks

Keyword(s):

Cell Fate ◽

Gene Dosage ◽

Signal Transduction Pathway ◽

Spatial Arrangement ◽

Complex Signal ◽

Chromosome 2 ◽

Wild Type ◽

Trichome Formation ◽

In The Wild ◽

Leaf Trichome

Abstract In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUS1 (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S::GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S::GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, try, and 35S::GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.

Download Full-text

Transcriptome Changes in Pseudomonas putida KT2440 during Medium-Chain-Length Polyhydroxyalkanoate Synthesis Induced by Nitrogen Limitation

International Journal of Molecular Sciences ◽

10.3390/ijms22010152 ◽

2020 ◽

Vol 22 (1) ◽

pp. 152

Author(s):

Dorota Dabrowska ◽

Justyna Mozejko-Ciesielska ◽

Tomasz Pokój ◽

Slawomir Ciesielski

Keyword(s):

Chain Length ◽

Nitrogen Limitation ◽

Stringent Response ◽

Wild Type ◽

Pseudomonas Putida Kt2440 ◽

Medium Chain ◽

Environmental Stimuli ◽

Medium Chain Length ◽

In The Wild

Pseudomonas putida’s versatility and metabolic flexibility make it an ideal biotechnological platform for producing valuable chemicals, such as medium-chain-length polyhydroxyalkanoates (mcl-PHAs), which are considered the next generation bioplastics. This bacterium responds to environmental stimuli by rearranging its metabolism to improve its fitness and increase its chances of survival in harsh environments. Mcl-PHAs play an important role in central metabolism, serving as a reservoir of carbon and energy. Due to the complexity of mcl-PHAs’ metabolism, the manner in which P. putida changes its transcriptome to favor mcl-PHA synthesis in response to environmental stimuli remains unclear. Therefore, our objective was to investigate how the P. putida KT2440 wild type and mutants adjust their transcriptomes to synthesize mcl-PHAs in response to nitrogen limitation when supplied with sodium gluconate as an external carbon source. We found that, under nitrogen limitation, mcl-PHA accumulation is significantly lower in the mutant deficient in the stringent response than in the wild type or the rpoN mutant. Transcriptome analysis revealed that, under N-limiting conditions, 24 genes were downregulated and 21 were upregulated that were common to all three strains. Additionally, potential regulators of these genes were identified: the global anaerobic regulator (Anr, consisting of FnrA, Fnrb, and FnrC), NorR, NasT, the sigma54-dependent transcriptional regulator, and the dual component NtrB/NtrC regulator all appear to play important roles in transcriptome rearrangement under N-limiting conditions. The role of these regulators in mcl-PHA synthesis is discussed.

Download Full-text

Overexpression of Mucin 1 Suppresses the Therapeutical Efficacy of Disulfiram against Canine Mammary Tumor

Animals ◽

10.3390/ani11010037 ◽

2020 ◽

Vol 11 (1) ◽

pp. 37

Author(s):

Ying Zhao ◽

Zixiang Lin ◽

Zhaoyan Lin ◽

Chaoyu Zhou ◽

Gang Liu ◽

...

Keyword(s):

Mammary Tumor ◽

Mammary Tumors ◽

Expression Level ◽

Canine Mammary Tumor ◽

Wild Type ◽

Mucin 1 ◽

Mammary Tumor Cell ◽

Mammary Tumor Cell Line ◽

Canine Mammary Tumors ◽

Wild Type Control

Mucin 1 (MUC1), a transmembrane protein, is closely associated with the malignancy and metastasis of canine mammary tumors; however, the role of overexpressed MUC1 in the development of cancer cells and response to drug treatment remains unclear. To address this question, we developed a new canine mammary tumor cell line, CIPp-MUC1, with an elevated expression level of MUC1. In vitro studies showed that CIPp-MUC1 cells are superior in proliferation and migration than wild-type control, which was associated with the upregulation of PI3K, p-Akt, mTOR, Bcl-2. In addition, overexpression of MUC1 in CIPp-MUC1 cells inhibited the suppressing activity of disulfiram on the growth and metastasis of tumor cells, as well as inhibiting the pro-apoptotic effect of disulfiram. In vivo studies, on the other side, showed more rapid tumor growth and stronger resistance to disulfiram treatment in CIPp-MUC1 xenograft mice than in wild-type control. In conclusion, our study demonstrated the importance of MUC1 in affecting the therapeutical efficiency of disulfiram against canine mammary tumors, indicating that the expression level of MUC1 should be considered for clinical use of disulfiram or other drugs targeting PI3K/Akt pathway.

Download Full-text