Parvalbumin: A Major Fish Allergen and a Forensically Relevant Marker

Parvalbumins (PVALBs) are low molecular weight calcium-binding proteins. In addition to their role in many biological processes, PVALBs play an important role in regulating Ca2+ switching in muscles with fast-twitch fibres in addition to their role in many biological processes. The PVALB gene family is divided into two gene types, alpha (α) and beta (β), with the β gene further divided into two gene types, beta1 (β1) and beta2 (β2), carrying traces of whole genome duplication. A large variety of commonly consumed fish species contain PVALB proteins which are known to cause fish allergies. More than 95% of all fish-induced food allergies are caused by PVALB proteins. The authentication of fish species has become increasingly important as the seafood industry continues to grow and the growth brings with it many cases of food fraud. Since the PVALB gene plays an important role in the initiation of allergic reactions, it has been used for decades to develop alternate assays for fish identification. A brief review of the significance of the fish PVALB genes is presented in this article, which covers evolutionary diversity, allergic properties, and potential use as a forensic marker

Fish parvalbumin gene: Detection and quantification by universal primers for forensic application

The substitution of illegal fish species poses economic, health and environmental risks. Identifying fish species, particularly closely related ones lacking external features, is a challenge. This study introduces an alternative approach using nuclear gene markers for positive detection, identification, and quantification of mitochondrial gene markers common in existing assays. We developed a universal primer targeting the parvalbumin (pvalb) β gene, a common fish allergen with an amplicon size of 117 bp long. The developed fish-specific primer assay was tested on a diverse panel of 54 fish species, including commonly consumed species such as salmon, carp, and cod, along with non-fish species such as Buffalo, chicken and pork, and vegetables such as wheat, celery, and mint. The assay consistently identified the fish pvalb gene, demonstrating our assay's high specificity and effectiveness in detecting this gene in a variety of fish species. The assay exhibited a low limit of detection (LOD) of 5 pg, detecting trace DNA quantities. The assay also effectively quantified parvalbumin with good efficiency and linearity. These findings highlight pvalb as a reliable forensic tool for the identification of fish species. Implementing nuclear gene markers mitigates fish mislabelling and fraud, reducing economic and environmental impacts

A comparison of blindpulling and blindwalking as measures of perceived absolute distance

Blindwalking has become a common measure of perceived absolute distance and location, but it requires a relatively large testing space and cannot be used with people for whom walking is difficult or impossible. In the present article, we describe an alternative response type that is closely matched to blindwalking in several important respects but is less resource intensive. In the blindpulling technique, participants view a target, then close their eyes and pull a length of tape or rope between the hands to indicate the remembered target distance. As with blindwalking, this response requires integration of cyclical, bilateral limb movements over time. Blind-pulling and blindwalking responses are tightly linked across a range of viewing conditions, and blind-pulling is accurate when prior exposure to visually guided pulling is provided. Thus, blindpulling shows promise as a measure of perceived distance that may be used in nonambulatory populations and when the space available for testing is limited

Identification of Fish Species and Targeted Genetic Modifications Based on DNA Analysis: State of the Art

Food adulteration is one of the most serious problems regarding food safety and quality worldwide. Besides misleading consumers, it poses a considerable health risk associated with the potential non-labeled allergen content. Fish and fish products are one of the most expensive and widely traded commodities, which predisposes them to being adulterated. Among all fraud types, replacing high-quality or rare fish with a less valuable species predominates. Because fish differ in their allergen content, specifically the main one, parvalbumin, their replacement can endanger consumers. This underlines the need for reliable, robust control systems for fish species identification. Various methods may be used for the aforementioned purpose. DNA-based methods are favored due to the characteristics of the target molecule, DNA, which is heat resistant, and the fact that through its sequencing, several other traits, including the recognition of genetic modifications, can be determined. Thus, they are considered to be powerful tools for identifying cases of food fraud. In this review, the major DNA-based methods applicable for fish meat and product authentication and their commercial applications are discussed, the possibilities of detecting genetic modifications in fish are evaluated, and future trends are highlighted, emphasizing the need for comprehensive and regularly updated online database resources