No abstract

Mutations in chloroplastic acetyl-CoA carboxylase (ACCase) gene enables molecular tools such as allele-specific PCR assay to monitor resistance alleles in green algae (Chlorophyta) Scenedesmus quadricauda. An isoleucine-leucine substitution in the gene encoding chloroplast (ACCase) conferred resistance to clodinafop-propargyl herbicide. Green algae cultures were treated with different concentrations of this herbicide (0, 1/16, 1/8, 1/4, 1/2, 1 and double of field concentration). The free amino acid content and cell number were determined after 0, 24, 48, 72 and 96 hrs.Concerning cell number, from the first to third generation, the number of cells decreased especially in the highest two concentrations. From the fourth to sixth generation the number of cells increased in all tested concentrations except the two highest concentrations. With regard to amino acid content, results indicated that from the first to sixth generation an increase occurred in amino acid content 24 hrs after exposure and decreased 48-96 hrs after exposure. In the fourth and fifth generation amino acid content increased, while in the sixth generation decreased. That might be explained by the recovery of algae activity at the sublethal concentrations, emergence of algae resistant population as well as increase in algae cell number. The results of allele-specific PCR revealed the presenence of (C) allele in algal cultures which explain the resistance to the herbicide used.

The present study aimed to investigate molecular sex differences between males and females of two members of family Cyprinidae in Egypt namely Benni and Lebeis using two different molecular markers i.e., start codon targeted polymorphism (SCoT) and inter simple sequence repeats (ISSR). The bulked DNA sample for each gender of the tested species was screened with eight primers from each marker. However, SCoT marker was more efficient than ISSR marker by showing higher number of possible sex-specific bands in the two tested species. SCoT primers were able to generate 7 and 4 malespecific bands, along with two and 5 female-specific bands for B. bynni and L. niloticus, respectively. Whereas, ISSR primers generated 4 and two malespecific bands, vis-à-vis two and three female-specific bands for B. bynni and L. niloticus, respectively. Interestingly, SCoT-01 primer generated unique common female specific band (690bp) which appeared only in the females of Benni and Lebeis. This band is more possible to be female sex-specific. The results obtained in this study could serve as a keystone for molecular sex differentiation studies in the two tested species and other fish species. However, increasing the number of analyzed individuals is highly recommended.

RAPD-PCR was performed using ten random primers to identify the genetic diversity among Rahmani, Chios and their crosses. The appearance of bands on gels would reflect the differences between genotypes of the examined animals. The differences would be detected by number and size of present or absent bands with each primer which could be used as positive or negative genetic markers to distinguish between breeds and their crosses. Primers A7, C7 and C1 were used for fingerprinting to identify the Rahmani breed, where they produced bands of 454 and 724 bp, respectively only with Rahmani breed. Presence of band at 410 bp with primer A9 would be used as a genetic marker for Chios breed. The presence of bands 1634, 1105, 223 and 187 bp with primer B17 and also bands 735, 683, 425 and 395 bp with primer A9 could be used as a fingerprinting for cross (½ C ½ R). Presence of bands 173, 132 and 122 bp with primer A5 would be used as a genetic marker for the reciprocal cross (½ R ½ C). The results of molecular DNA of the experimental sheep breeds and their crosses, showed that polymorphism within crosses is higher than polymorphism within the pure breeds of Rahmani and Chios. Fragments generated by primers showed a polymorphism ratio of 10.8 % between Rahmani and Chios and 25 % between crosses (½ C ½ R and ½ R ½ C). Also, the similarity between Rahmani and Chios breeds was 89.1 %, while it was 75 % between crosses. The results asserted that fingerprinting (RAPD-PCR genetic marker) technique would be a useful tool to differentiate sheep breeds and their crosses.

No abstract