Preliminary analysis of pathways and their implications during salinity stress in abalone

Transcriptome sequencing has offered immense opportunities to study non-model organisms. Abalone is an important marine mollusk that encounters harsh environmental conditions in its natural habitat and under aquaculture conditions; hence, research that increases molecular information to understand abalone physiology and stress response is noteworthy. Accordingly, the study used transcriptome sequencing of the gill tissues of abalone exposed to low salinity stress. The aim is to explore some enriched pathways during salinity stress and the crosstalk and functions of the genes involved in the candidate biological processes for future further analysis of their expression patterns. The data suggest that abalone genes such as YAP/TAZ, Myc, Nkd, and Axin (involved in the Hippo signaling pathway) and PI3K/Akt, SHC, and RTK (involved in the Ras signaling pathways) might mediate growth and development. Thus, deregulation of the Hippo and Ras pathways by salinity stress could be a possible mechanism by which unfavorable salinities influence growth in abalone. Furthermore, PEPCK, GYS, and PLC genes (mediating the Glucagon signaling pathway) might be necessary for glucose homeostasis, reproduction, and abalone meat sensory qualities; hence, a need to investigate how they might be influenced by environmental stress. Genes such as MYD88, IRAK1/4, JNK, AP-1, and TRAF6 (mediating the MAPK signaling pathway) could be useful in understanding abalone's innate immune response to environmental stresses. Finally, the aminoacyl-tRNA biosynthesis pathway hints at the mechanism by which new raw materials for protein biosynthesis are mobilized for physiological processes and how abalone might respond to this process during salinity stress. Low salinity clearly regulated genes in these pathways in a time-dependent manner, as hinted by the heat maps. In the future, qRT-PCR verification and in-depth study of the various genes and proteins discussed would provide enormous molecular information resources for the abalone biology.

Study of the antimicrobial activity of zinc oxide nanostructures mediated by two morphological structures of leaf extracts of Eucalyptus radiata

The growing microbial resistance against antibiotics and the development of resistant strains has shifted the interests of many scientists to focus on metallic nanoparticle applications. Although several metal oxide nanoparticles have been synthesized using green route approach to measure their antimicrobial activity, there has been little or no literature on the use of Eucalyptus robusta Smith aqueous leaf extract mediated zinc oxide nanoparticles (ZnONPs). The study therefore examined the effect of two morphological nanostructures of Eucalyptus robusta Sm mediated ZnONPs and their antimicrobial and antifungal potential on some selected pathogens using disc diffusion method. The samples were characterized using Scanning and Transmission Electron Microscopy, Energy-Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy. From the results, the two ZnO samples were agglomerated with zinc oxide nanocrystalline structure sample calcined at 400 °C (ZnO NS400) been spherical in shape while zinc oxide nanocrystalline structure sample calcined at 60 °C (ZnO NS60) was rod-like. The sample calcined at higher temperature recorded the smallest particle size of 49.16 ± 1.6 nm as compared to the low temperature calcined sample of 51.04 ± 17.5 nm. It is obvious from the results that, ZnO NS400 exhibited better antibacterial and antifungal activity than ZnO NS60. Out of the different bacterial and fungal strains, ZnO NS400 sample showed an enhanced activity against S. aureus (17.2 ± 0.1 mm) bacterial strain and C. albicans (15.7 ± 0.1 mm) fungal strain at 50 mg/ml. Since this sample showed higher antimicrobial and antifungal activity, it may be explored for its applications in some fields including medicine, agriculture, and aquaculture industry in combating some of the pathogens that has been a worry to the sector. Notwithstanding, the study also provides valuable insights for future studies aiming to explore the antimicrobial potential of other plant extracts mediated zinc oxide nanostructures.

Identification and expression analysis of cobia (Rachycentron canadum) liver-related miRNAs under hypoxia stress

At present, due to the influence of global warming, seasonal change, diurnal variation, and eutrophication of the water body, hypoxia has become one of the major factors limiting the stable development of cobia (Rachycentron canadum) culture. In this study, the miRNAs involved in hypoxia stress were screened, and the target genes of miRNAs were annotated and analyzed. The results showed that a total of 184 conservative microRNA (miRNA) and 121 newly predicted miRNA were obtained by sequencing the liver of control (C) and hypoxic (dissolved oxygen, DO (2.64 ± 0.25) mg/L; 3 h) (S) groups. The pathways involved in energy metabolism included starch and sucrose metabolism (ko00500), glycosaminoglycan degradation (ko00531), and galactose metabolism (ko00052). The results indicate that the body maintains physiological activities by regulating some important pathways at the transcriptional level under hypoxia stress, such as the conversion of aerobic metabolism and anaerobic metabolism, the reduction of energy consumption, and the promotion of red blood cell proliferation to maintain the homeostasis of the body.

A Review on Sex Steroid Hormone Estrogen Receptors in Mammals and Fish

Steroid hormones play essential roles in the reproductive biology of vertebrates. Estrogen exercises its effect through estrogen receptors and is not only a female reproductive hormone but acts virtually in all vertebrates, including fish, and is involved in the physiological and pathological states in all males and females. Estrogen has been implicated in mandible conservation and circulatory and central nervous systems as well as the reproductive system. This review intended to understand the structure, function, binding affinities, and activations of estrogens and estrogen receptors and to discuss the understanding of the role of sex steroid hormone estrogen receptors in mammals and fish.

Identification, characterization, and expressions profile analysis of growth hormone receptors (GHR1 and GHR2) in Hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus polyphekadion ♂)

Growth hormone is an essential hormone that plays essential roles in growth, metabolism, cellular differentiation, immunity and reproduction in fish, by means of the growth hormone receptors. The encoding cDNA growth hormone receptors (GHR1 and GHR2) were cloned and characterized from Hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus polyphekadion♂). Sequence analysis of the cloned GHR1 was observed as containing 2176, which comprised an ORF of 1842 bp, 5 UTR of 6 bp and 3 UTR of 328 bp, with 612 amino acids encoding proteins, while GHR2 was observed as containing 1824 bp that encompassed an ORF of 708 bp, 5 UTR of 48 bp and 3 UTR of 1068 bp with 235 amino acids encoding proteins. Relative mRNA expression of GHR1 and GHR2 in the liver and muscle was found to be highest respectively. Our findings provide vital statistics of GHRs likely to play a significant role in the growth of the fish.