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1.
Electrophoretic studies of the degree and pattern of polymorphism at two third-chromosome loci, esterase-6 (Est-6) and phosphoglucomutase (PGM), were carried out in three Drosophila melanogaster populations collected from different localities in Iraq: Mosul, Tuwaitha, and Basrah. The results show that only the Tuwaitha population was polymorphic for both loci; the other two populations were polymorphic for Est-6 and monomorphic for PGM. The allele frequency changes at both loci were followed for 20 generations in an experimental cage derived from the Tuwaitha population; it was found that there is a deviation from Hardy-Weinberg equilibrium at both loci toward the homozygote. 相似文献
2.
An in vitro root explant tissue culture technique is described for determining susceptibility of tomato (Lycopersicon esculentum Mill.) breeding lines and cultivars to the root-knot nematode Meloidogyne incognita. Root explants were taken from 2-day-old seedlings cultured for 30 days at 28 C on Gamborg''s B-5 medium with or without nematode inoculum. The remaining portion of the root and stem from the excised root explants was transferred to soil in pots and grown to maturity in the greenhouse. In vitro root explants were evaluated for growth and occurrence of juveniles, adults, and egg masses. The regenerated plants were used to produce more seed, The proposed technique is simple, reliable, and adapted to routine screening of large numbers of F₁ and F₂ samples, and it utilizes less space than tests performed on intact plants in the greenhouse or growth chamber. Evidence is presented also on the breakdown of resistance to M. incognita under high temperature stress using this in vitro root explant technique. 相似文献
3.
Portulaca oleracea leaves were found to contain 0.42% of a mucilage mixture. The mucilage was fractionated into an acidic and a neutral fraction. The acidic fraction consists of galacturonic acid residues joined by α-(1→4)-linkages; 60% of these residues are present as the calcium salt, and esterified galacturonic acid residues are absent. The neutral fraction is composed of 41% of arabinose and 43% of galactose residues, besides traces of rhamnose residues. 相似文献
4.
Sanaa Hamdy Omar Siegfried Honecker Hans-Jürgen Rehm 《Applied microbiology and biotechnology》1992,36(4):518-524
Summary The formation of citric acid, oxalic acid, erythritol and glycerol by three strains of Aspergillus niger immobilized in calcium alginate was investigated and compared with that of free cells when cultivated in shake flasks under phosphate limitation. Morphological changes were followed using an electron microscope. The production of acids and polyols, the consumption of glucose and fructose, and also the morphological changes were strain-dependent. The results also reflected the influence of long storage of a strain on productivity, morphological behaviour and phosphate consumption.
Offprint requests to: H.-J. Rehm 相似文献
5.
New Ceratopogonidae from the Early Cretaceous amber of Hammana (Central Lebanon) are studied. Five new species (Lebanoculicoides daheri sp. nov., Protoculicoides krzeminskii sp. nov., Archiaustroconops annae sp. nov., Archiaustroconops hammanensis sp. nov., and Archiaustroconops dominiakae sp. nov.) are characterized, described, illustrated, and compared with other Cretaceous taxa. New keys for species of the three genera Lebanoculioides, Protoculicoides, and Archiaustroconops, but also for all genera of Lebanese fossil biting midges, are proposed. 相似文献
6.
Daria Grafodatskaya Barian HY Chung Darci T Butcher Andrei L Turinsky Sarah J Goodman Sana Choufani Yi-An Chen Youliang Lou Chunhua Zhao Rageen Rajendram Fatima E Abidi Cindy Skinner James Stavropoulos Carolyn A Bondy Jill Hamilton Shoshana Wodak Stephen W Scherer Charles E Schwartz Rosanna Weksberg 《BMC medical genomics》2013,6(1):1-18
Background
A number of neurodevelopmental syndromes are caused by mutations in genes encoding proteins that normally function in epigenetic regulation. Identification of epigenetic alterations occurring in these disorders could shed light on molecular pathways relevant to neurodevelopment.Results
Using a genome-wide approach, we identified genes with significant loss of DNA methylation in blood of males with intellectual disability and mutations in the X-linked KDM5C gene, encoding a histone H3 lysine 4 demethylase, in comparison to age/sex matched controls. Loss of DNA methylation in such individuals is consistent with known interactions between DNA methylation and H3 lysine 4 methylation. Further, loss of DNA methylation at the promoters of the three top candidate genes FBXL5, SCMH1, CACYBP was not observed in more than 900 population controls. We also found that DNA methylation at these three genes in blood correlated with dosage of KDM5C and its Y-linked homologue KDM5D. In addition, parallel sex-specific DNA methylation profiles in brain samples from control males and females were observed at FBXL5 and CACYBP.Conclusions
We have, for the first time, identified epigenetic alterations in patient samples carrying a mutation in a gene involved in the regulation of histone modifications. These data support the concept that DNA methylation and H3 lysine 4 methylation are functionally interdependent. The data provide new insights into the molecular pathogenesis of intellectual disability. Further, our data suggest that some DNA methylation marks identified in blood can serve as biomarkers of epigenetic status in the brain. 相似文献7.
Petek E Schwarzbraun T Noor A Patel M Nakabayashi K Choufani S Windpassinger C Stamenkovic M Robertson MM Aschauer HN Gurling HM Kroisel PM Wagner K Scherer SW Vincent JB 《Molecular genetics and genomics : MGG》2007,277(1):71-81
We recently reported the disruption of the inner mitochondrial membrane peptidase 2-like (IMMP2L) gene by a chromosomal breakpoint in a patient with Gilles de la Tourette syndrome (GTS). In the present study we sought
to identify genetic variation in IMMP2L, which, through alteration of protein function or level of expression might contribute to the manifestation of GTS. We screened
39 GTS patients, and, due to the localization of IMMP2L in the critical region for the autistic disorder (AD) locus on chromosome 7q (AUTS1), 95 multiplex AD families; however,
no coding mutations were found in either GTS or AD patients. In addition, no parental-specific expression of IMMP2L was detected in somatic cell hybrids containing human chromosome 7 and human cell lines carrying a maternal uniparental disomy
for chromosome 7 (mUPD7). Despite the fact that no deleterious mutations in IMMPL2 (other than the inverted duplication identified previously) were identified in either GTS or AD, this gene cannot be excluded
as a possible rare cause of either disorder. 相似文献
8.
Toxicity of fipronil was evaluated against field-collected Coptoteres formosanus Shiraki. In topical application assays, fipronil was highly effective against both workers and soldiers at very low doses. Acute toxicity after 24 h was significantly greater in workers than in soldiers. The LD50s were 2.59- and 2.91-fold greater with soldiers than with workers from the two tested colonies. The LD50s of fipronil at 72 h after treatment were <2.0 ng/insect, with no significant differences regarding the tested workers/soldiers or colonies. Treated soldiers placed with untreated workers significantly increased worker mortality. However, there was no significant horizontal transmission of fipronil from treated workers to untreated soldiers. Fipronil at rates of 0.063% or less showed no repellency, whereas sand treatments of 0.125% fipronil were repellent to termite workers. 相似文献
9.
Akdi K Vilaplana RA Kamah S Navarro JA Salas JM González-Vílchez F 《Journal of inorganic biochemistry》2002,90(1-2):51-60
The new dipalladium complex [Pd(2)(mu-mtpo-N(3),N(4))(2)(phen)(2)](NO(3))(2) (where phen=1,10-phenantroline; Hmtpo=5,7-dihydro-7-oxo-5-methyl[1,2,4]triazolopyrimidine), (Pd(2)-Hmtpo, or complex I), interacts effectively with DNA plasmid (pBS), as studied by circular dichroism spectroscopy (CD), causing large helix distortions, altering the direction of the main DNA helix axis and producing unwinding of the DNA double helix. DNA damage induced by complex I was highly significant at 2.81 microM (ovarian carcinoma TG cell line), as assessed by comet assay, a dose at which all treated nuclei showed more than 30% DNA migration to the comet tail. DNA damage effect is a consequence of genotoxicity and not a false positive response caused by cytotoxicity. In vitro cytotoxic assay on the two human tumor cell lines TG and BT-20 (breast carcinoma), shows that doses of 0.47, 1.41 and 2.81 microM produce significant antiproliferative effects after 4 days of treatment compared with control. Complex I was highly cytotoxic at 2.81 microM causing an inhibition of viable cells of 65.5%. Cisplatin (cis-DDP) exhibits lower cytotoxic activity in TG cells than dipalladium complex (a cisplatin dose of 6.67 microM inhibits 30.3%) and does not cause migration of DNA to comet tail. 相似文献
10.
Target site studies were undertaken to examine the difference in susceptibility of Formosan subterranean termite, Coptotermes formosanus Shiraki, workers and soldiers to chlorpyrifos. Workers exhibited significantly greater acetylcholinesterase activity per insect than soldiers (118.63 +/- 48.51 versus 47.98 +/- 22.59 mOD/min/insect equivalent). Likewise, enzyme activity (mean +/- SD) per milligram of protein was greater in workers than soldiers (440.30 +/- 267.43 versus 311.53 +/- 149.83 mOD/min/mg protein). The enzyme of soldiers was more sensitive to the acetylcholinesterase (AChE) inhibitors eserine and chlorpyrifos-oxon than that of workers. The I50s of chlorpyrifos-oxon were 2.66 and 4.59 nM for soldiers and workers, respectively, whereas the I50s of eserine were 16.56 and 25.41 nM for soldiers and workers, respectively. The amount of protein was significantly higher in workers than in soldiers with mean values of 0.270 +/- 0.102 and 0.154 +/- 0.054 mg/insect equivalent, respectively. We suggest that the differential response of workers and soldiers to chlorpyrifos may be due to the difference in AChE sensitivity to inhibition and the amount of protein between them. 相似文献