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Pharmaceuticals and Nutraceuticals from Fish Wastes and Their Activities
Published in Ramasamy Santhanam, Santhanam Ramesh, Subramanian Nivedhitha, Subbiah Balasundari, Pharmaceuticals and Nutraceuticals from Fish and Fish Wastes, 2022
Ramasamy Santhanam, Santhanam Ramesh, Subramanian Nivedhitha, Subbiah Balasundari
Milt (soft roe) which is the fried and salted male sexual organs with semen is also a delicacy and is utilized as a topping for pasta dishes. Milt produced from herrings, cod, tuna, and carp is popular in Russia, Japan, Sicily, and Romania, respectively (Anon., https://www.eurofishmagazine. com/sections/fisheries/item/445-fish-entrails-and-processing-waste-as-a-raw-material). The livers of fishes such as cod, haddock, and blue ling are also nutritionally important. In Norwegian Lofoten Islands, cod liver is consumed as a sauce. The fried fatty livers of anglerfish (Lophius piscatoius) is also a delicacy in many countries (Anon., https://www.eurofishmagazine.com/sections/fisheries/item/445-fish-entrails-and-processing-waste-as-a-raw-material).
Profile of Toxic Pufferfish
Published in Ramasamy Santhanam, Biology and Ecology of Toxic Pufferfish, 2017
Once introduced, the group is conditioned with a high quality diet including meaty frozen foods such as bloodworm and small snails. Courtship begins with the male pursuing the female vigorously, often resorting to biting and nipping if she appears disinterested. A successful chase normally ends with the female being driven into a patch of low-lying vegetation where they come together for a few seconds, releasing eggs and milt simultaneously. The near-transparent eggs are tiny (~1mm in dia.), non-adhesive and will simply develop where they fall. This sequence may be repeated several times. Egg numbers tend to be very low, with most spawning events resulting in a yield of ten or less. The eggs may be removed with a large pipette.
Disruption of Nongenomic Steroid Actions on Gametes and Serotonergic Pathways Controlling Reproductive Neuroendocrine Function by Environmental Chemicals
Published in Rajesh K. Naz, Endocrine Disruptors, 2004
The final criterion that needs to be satisfied for a binding moiety to be designated as a receptor is that changes in receptor abundance are consistent with its proposed physiological functions. In male fish the prespawning surge in plasma gonadotropin levels causes increases in MIS production and milt volume. It was found that hormonal stimulation of gonadotropin secretion by GnRH injection caused a two-to threefold increase in sperm 20β-S concentrations 2 days later, which was accompanied by an increase in milt volume. Similarly, incubation of minced croaker and seatrout testicular tissues with gonadotropin for 18 hours increased sperm receptor levels severalfold compared to controls [60, 119]. Therefore, sperm membrane 20β-S binding in both species fulfills all the criteria for their designation as hormone receptors.
Improvement of sperm motility of Oncorhynchus mykiss and Salvelinus fontinalis by L-tryptophan
Published in Systems Biology in Reproductive Medicine, 2019
Mehmet Kocabaş, Filiz Kutluyer, Özlem Ertekin, Önder Aksu, Nadir Başçınar
Total bacteria count in fresh sperm (undiluted samples) was not detectable and not detected in sperm samples treated with different L-tryptophan concentrations. Yeast-mold, Enterobacteriaceae and Micrococcus/Staphylococcus were not detected from fresh and treated sperm (day 0, 2, 4, 6 and 12) brook trout (S. fontinalis) and rainbow trout (O. mykiss). Although there is no study in fish sperm about the effect of L-tryptophan on bacterial flora or count after short-term storage, the total bacteria count has been evaluated in fresh sperm of rainbow trout. Kubilay et al. (2009) reported the total bacteria count in milt of rainbow trout as 2.0 × 103 cfu/mL due to the inadequate hygienic condition in water. Ercan and Ekici (2016) determined that high bacterial colony (>500) in fresh semen samples. Sperm motility and longevity may reduce with microbial contamination in anaerobic conditions (Niksirat et al. 2011). At this point, cell rupture and death can occur (Keogh et al. 2017). Sperm collection method, non-sterile solutions, and process of storage can all contribute to microbial contamination (Niksirat et al. 2011; Keogh et al. 2017).
Protein evolution revisited
Published in Systems Biology in Reproductive Medicine, 2018
Peter L. Davies, Laurie A. Graham
The repeated evolution (reinvention) of linear repetitive proteins like type I AFP or the AFGPs, which are >60% one amino acid type and have only secondary structure, is plausible. But for the C-type lectin type II AFP with a diverse amino acid composition, five disulfide bridges in exactly the same locations, and clear-cut sequence homology, it is inconceivable that this protein could have been reinvented three times during the evolution of fishes. There had to be another explanation for the scattered distribution of this complex globular antifreeze in three well-separated branches of teleosts. When comparing the genes from the most phylogenetically distant fishes – the herring and smelt, we realized that the intron sequences of their type II AFP genes are around 97% identical, whereas the introns of non-AFP genes are very dissimilar. Clearly the AFP genes diverged less than a few 10s of millions of years ago, even though the two species separated ~200 mya ago. The only explanation for this phenomenon is lateral gene transfer between vertebrate species, which was heresy at the time this report was published in PLoS ONE (Graham et al. 2008). A follow-up study showed that the type II AFP gene had been deposited in an intergenic region of the smelt genome, between two known genes (Graham et al. 2012). Syntenic comparisons showed that the corresponding region of other teleosts had the same flanking genes but without any insertions of AFP or C-type lectin genes. Thus, the pattern of genes was only interrupted in the smelt. The most plausible explanation for how this lateral transfer happened is that these fishes fertilize their eggs externally and their spawning ranges overlap. We suspect that herring DNA derived from milt was in contact with smelt sperm during fertilization of smelt eggs and was drawn into the region where the two pronuclei fuse and became incorporated into the embryo. This piggy-backing of foreign DNA on sperm has been used as a way to produce transgenic animals (Patil and Khoo 1996; Collares et al. 2010) and although it is likely to be an extremely rare event in nature, the conferring of a beneficial trait – the ability to prevent death in icy seawater – can be highly selected for, as is antibiotic resistance in bacteria.