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Surveillance and Control Programs for Cestode Diseases
Published in Max J. Miller, E. J. Love, Parasitic Diseases: Treatment and Control, 2020
Kumaratilake and Thompson have proven the existence of three different strains of E. granulosus in Australia on the basis of developmental, morphologic, and biochemical characteristics.14 Two strains are maintained primarily in sheep/dog cycles. One is found on the Australian mainland, and the other is limited to the island of Tasmania. The third strain is perpetuated in a dingo/macropod marsupial cycle. Since morphologic and developmental characteristics have limitations for demonstrating genetic differences, the workers characterized these different strains by protein and enzyme separative techniques. By revealing the products of structural genes, these methods provide a convenient basis for the genetic characterization of different populations and for assessing the degree of differences between such groups. As yet, no agreement has been reached on the formal taxonomic status of infraspecific variants, nor has anyone yet explained the mechanism by which these parasites, often existing sympatrically, are able to maintain their genetic distinctiveness.
Mycobacterium tuberculosis
Published in Lloyd N. Friedman, Martin Dedicoat, Peter D. O. Davies, Clinical Tuberculosis, 2020
Thus, we know that that INH, when activated by the katG-encoded catalase peroxidase, forms an adduct with NAD that inhibits the enoyl reductase of mycolic acid synthase. As predicted for a drug target, a mutation within the structural gene that confers resistance would display reduced binding of the drug. This was observed for the INH-NAD adduct.79 In addition to structural mutations, target proteins can also confer resistance by target overexpression thereby titrating the inhibitor.51
Acute and Chronic Transforming Retroviruses
Published in Pimentel Enrique, Oncogenes, 2020
The virions of nonacute retroviruses contain two copies of genomic RNA, which in MuLV are approximately 8000 bases in length, capped at the 5′ end and polyadenylated at the 3′ end.129 The single-stranded RNA genome of nonacute viruses contains 3 structural genes (5′-gag-pol-env-3′) but do not contain oncogenes. The genes gag and env code for structural protein components of the virus particle, whereas the gene pol code for the enzyme reverse transcriptase (RT), which is an RNA-directed DNA polymerase. The protein products of the three structural genes are well characterized. At both ends of the genome there are short repeated stretches of noncoding sequences, designated r, and unique sequences near the 5′ and 3′ termini, designated U5 and U3, respectively (Figure 1).
Heterochromatin extension: a possible cytogenetic fate of primary amenorrhea along with normal karyotype
Published in Journal of Obstetrics and Gynaecology, 2022
Bishal Kumar Dey, Shanoli Ghosh, Ajanta Halder, Somajita Chakraborty, Sanchita Roy
There are some patients with PA who do not have any kind of chromosomal abnormalities except heterochromatin extension in different autosomes. It has been established that heterochromatin polymorphisms that are identified cytogenetically are not clinically significant. In the general population, heterochromatin region increase in chromosome 1/9/16/Y has been identified. These heterochromatin regions consist of repeated DNA sequences and not structural genes. However, recent studies have proposed that alteration in length of heterochromatin region may play a role in recurrent miscarriage. Küçük et al. established probable association of heterochromatin polymorphism in chromosome 6 with premature ovarian failure. None the less, there are a small number of publications regarding the association of heterochromatin polymorphism in patient with PA. From here, the aim of investigation is born to find out those females having PA along with heterochromatin extension in autosomes. This comprehensive study has targeted females with PA and their genetic morphology and relevant hormonal parameters funded by Department of Science, Technology and Biotechnology (DSTBT), Govt. of West Bengal. This initiative also aims to create a social adaptation in females which is an integral part of women empowerment program in our country, India.
An overview of sex and reproductive immunity from an evolutionary/anthropological perspective
Published in Immunological Medicine, 2021
Yoshihiko Araki, Hiroshi Yoshitake, Kenji Yamatoya, Hiroshi Fujiwara
So how did mammals acquire the placenta? The human genome (all the DNA on chromosomes) is composed of approximately 3 billion base pairs. However, only a small proportion of the genome actually encodes proteins (the structural genes). The remaining genome contains sequences called ‘transposons’ [21], some of which are thought to be derived from ‘retroviruses’ such as human immunodeficiency virus. This suggests that during viral infections throughout evolutionary history, viruses were incorporated into the chromosomes of the infected organisms and passed down to the next generation through assimilation. The placenta has a completely different shape depending on the species. One hypothesis is that genes derived from retroviruses, Peg10/Sirh1 and Peg11/Sirh2, were important in the evolution of placental development [22–24]. The diversity of placental form and function is thought to be the result of successive, independent events [25].
“I will survive”: A tale of bacteriophage-bacteria coevolution in the gut
Published in Gut Microbes, 2019
Luisa De Sordi, Marta Lourenço, Laurent Debarbieux
The contextual genomic variability of bacteriophages was also analysed by sequencing five adapted bacteriophages differing in their ability to infect the five MG1655 clones considered (Fig. 1C). The only bacteriophage able to infect all the bacterial clones had the largest number of mutations (12 mutations, versus 5 to 9 in the other bacteriophages isolated; Table S1), suggesting a possible faster pace of adaptation in response to bacterial resistance. The mutations were clustered into four genomic regions. The first corresponds to the rIIA (gp37) gene, the function of which is probably related to infection fitness, as this gene was also highlighted in our population genomics study in in vitro conditions.24 A second, larger region encompasses several structural genes, including the tail fibre genes. The gp55 and gp57 genes, which are predicted to encode two subunits of the class I ribonucleotide reductase, were also affected, together with gp108, the function of which is unknown.