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Fulltext Regulation of nerve growth and patterning by cell surface protein disulphide isomerase

Cook GM, Sousa C, Schaeffer J, Wiles K, Jareonsettasin P, Kalyanasundaram A, et al.

Elife, 2020 05 28;9.
PMID: 32452761 DOI: 10.7554/eLife.54612

Contact repulsion of growing axons is an essential mechanism for spinal nerve patterning. In birds and mammals the embryonic somites generate a linear series of impenetrable barriers, forcing axon growth cones to traverse one half of each somite as they extend towards their body targets. This study shows that protein disulphide isomerase provides a key component of these barriers, mediating contact repulsion at the cell surface in chick half-somites. Repulsion is reduced both in vivo and in vitro by a range of methods that inhibit enzyme activity. The activity is critical in initiating a nitric oxide/S-nitrosylation-dependent signal transduction pathway that regulates the growth cone cytoskeleton. Rat forebrain grey matter extracts contain a similar activity, and the enzyme is expressed at the surface of cultured human astrocytic cells and rat cortical astrocytes. We suggest this system is co-opted in the brain to counteract and regulate aberrant nerve terminal growth.

Matched MeSH terms: Somites/embryology; Somites/physiology
Fulltext Effects of Pegagan (Centella asiatica L.) Ethanolic Extract SNEDDS (Self-nanoemulsifying Drug Delivery Systems) on the Development of Zebrafish (Danio rerio) Embryos

Hayati F, Chabib L, Fauzi IS, Awaluddin R, Sumayya, Faizah WS, et al.

J Pharm Bioallied Sci, 2020 10 08;12(4):457-461.
PMID: 33679093 DOI: 10.4103/jpbs.JPBS_297_19

Introduction: Pegagan is a traditional medicinal plant with three major bioactive properties, triterpenoid, steroids, and saponin. It has the properties of antioxidant, antistress, and wound healing. Pegagan extract is prepared in self-nanoemulsifying drug delivery systems (SNEDDS) to overcome the problem of low water-solubility level.
Objectives: This study aimed to observe the effect of pegagan ethanolic extract SNEDDS on the development of zebrafish embryos.
Materials and Methods: This study used 12 sets of zebrafish embryos presented in five sets of extract SNEDDS with different concentrations, that is, 20, 10, 5, 2.5, and 1.25 μg, five sets of SNEDDS without extract with different concentrations, that is, 20, 10, 5, 2.5, and 1.25 μg, a set of positive control (3.4-DCA 4 mg/L) with one control set (diluted with water), and a negative control (SNEDDS without extract). The procedure was conducted for 96 h with observations every 24 h. The parameters observed were embryonic coagulation, formation of somites, detachment of tail bud from the yolk, and abnormality of embryo.
Results: The results showed that in 96 h the 20ppm concentration caused 100% mortality. Embryo abnormality appeared as coagulation of embryo, somite malformation, and abnormal tail.
Discussion: There is a correlation between the concentration of SNEDDS and the incidence of embryo coagulation. The malformation in the group of pegagan extract SNEDDS is characterized by cardiac edema, somite malformation, and abnormal tail.
Conclusion: Pegagan ethanolic extract SNEDDS of 20ppm can inhibit the development of zebrafish embryos.

Matched MeSH terms: Somites
5'-flanking sequences of zebrafish fast myosin heavy chain genes regulate unique expression in the anterior, medial subsection and posterior tail somites of the skeletal muscle

Asaduzzaman M, Shakur Ahammad AK, Asakawa S, Kinoshita S, Watabe S

Comp Biochem Physiol B Biochem Mol Biol, 2016 Jan;191:1-12.
PMID: 26335505 DOI: 10.1016/j.cbpb.2015.08.009

In zebrafish, fast muscle-specific myosin heavy chain genes have their unique expression patterns in a well-defined and restricted region of the skeletal muscle. However, the transcriptional regulatory mechanisms involved have remained unclear. Here, we examined the regulation of spatio-temporal expression patterns of myhz1 (myhz1.1, myhz1.2 and myhz1.3) and myhz2 during their development by using transient gene and stable transgenic techniques. Embryos microinjected with different length 5'-flanking sequences of myhz1 conjugated with the enhanced green fluorescent protein (EGFP) gene showed EGFP expression in the anterior and medial subsections of somites, but not in the tail somite region. In contrast, embryos microinjected with different length 5'-flanking sequences of myhz2 showed EGFP expression exclusively at the posterior tail somite domain. Promoter deletion analyses demonstrated that reduced EGFP fluorescence typically is correlated with smaller 5'-flanking sequences. The immunohistochemical observation revealed that zebrafish larvae provided with the transient gene and those from stable transgenic lines consistently expressed EGFP in the fast muscle fibers. r-VISTA plot identified one common conserved region of about 140°bp among myhz1.1, myhz1.2 and myhz1.3. Deletion of this conserved region from the 5'-flanking sequence of each myhz1 markedly reduced EGFP expression in its unique spatial somite region. Deletion mutation analysis demonstrated that myhz2 expression in the tail somite region might be mediated by Tbx (family of transcription factors having a common DNA-binding sequence known as T-box) binding elements. In summary, 5'-flanking sequences of myhz1 and myhz2 regulate their unique expression patterns in a well-defined and restricted somite region of the skeletal muscle in zebrafish.

Matched MeSH terms: Somites
Fulltext Expression of receptor-interacting protein (RIP 140) in zebrafish tissues and embryonic stages

Teoh, P.H., Kuah, M.K., Lim, P.S., Muhammand, T.S.T., Najimudin, N., Chien, A.S.C.

ASM Science Journal, 2010;4(2):123-132.
MyJurnal

The receptor-interacting protein 140 (RIP 140) is a well known nuclear repressor and has been shown to be crucial for female reproduction and metabolism. However, the function of this repressor in developmental processes is still unknown. We conducted a study to investigate the expression patterns of RIP 140 in developing zebrafish embryos. Semi-quantitative RT-PCR analysis revealed that RIP140 was highly expressed in the eye, swim bladder, reproductive and metabolic organs of adult zebrafish. During embryogenesis, RIP 140 mRNA was continuously expressed throughout all the developmental stages with the highest expression at 24 hours of post-fertilization (hpf). Furthermore, in situ hybridization whole-mounts revealed that the expression of this gene was mainly localized in the eyes, mid-brain, pectoral fin buds and somites. Therefore, this present study has provided a starting point for future investigations to examine the role of RIP 140 in the development of these organs.

Matched MeSH terms: Somites
Diagnostic pitfalls in the evaluation and management of amenorrhea in adolescents

Azurah AG, Zainuddin AA, Jayasinghe Y

J Reprod Med, 2013 Jul-Aug;58(7-8):324-36.
PMID: 23947083

Amenorrhea is a common menstrual problem seen in adolescents. Amenorrhea has been shown to have a negative impact on adolescents' quality of life. In this paper we discuss the various causes and investigations of amenorrhea in adolescents and address management dilemmas for specific conditions. Specific approaches in dealing with adolescents using the HEADSS (Home, Education, Activity, Drugs, Sexual activity, Suicidal) approach are discussed.

Matched MeSH terms: Somites/abnormalities