Abtract
Mucosal surfaces are the main route of entry for pathogens in all living organisms. In the case of teleost fish, mucosal surfaces cover the vast majority of the animal. As these surfaces are in constant contact with the environment, fish are perpetually exposed to a vast number of pathogens. Despite the potential prevalence and variety of pathogens, mucosal surfaces are primarily populated by commensal non-pathogenic bacteria. Indeed, a fine balance between these two populations of microorganisms is crucial for animal survival. This equilibrium, controlled by the mucosal immune system, maintains homeostasis at mucosal tissues. Teleost fish possess a diffuse mucosal-associated immune system in the intestine, with B cells being one of the main responders. Immunoglobulins produced by these lymphocytes are a critical line of defense against pathogens and also prevent the entrance of commensal bacteria into the epithelium. In this review we will summarize recent literature regarding the role of B lymphocytes and immunoglobulins in gut immunity in teleost fish, with specific focus on immunoglobulin isotypes and the microorganisms, pathogenic and non-pathogenic, that interact with the immune system.
1. Introduction
Aquatic environments provide an ideal setting for the growth of a variety of microorganisms that are in continuous contact with the mucosal surfaces of the fish body (Gomez et al., 2013). Although all mucosal surfaces of their body are constantly exposed to the
Answer: Innate immune system or nonspecific resistance is also known as first line of defense. It’s nonspecific that means not design to target any specific microorganisms. Response time for innate immune system is very quick compare to adaptive immune system. These infections inhibited by the substance that change the humoral or cellular component of the host that mediated non specific resistance. They are not specific means they provide protection against a spectrum of organism. And they are vitamin, minerals, fatty acid and microbial product. These substances are major part of our diet. We consume food and get from it. Diet has both
During the year, microbes appeared sometime in March while humans have been here for 30 mins or fewer (11*). Ed Yong uses this fact as a springboard to explore and explain the complex relationships that exist between microbes and animals. After confirming that microbes have been here way longer than anyone of us, he gets into the thick of it by discussing the sheer ubiquity of microbes, which exist in every conceivable place. From everything you touch to the piping hot underwater vents where nothing else lives. It is as if everything has an extra invisible microbial layer.
Method of pathogen introduction to a non-pathogenic environment includes brood stock, Aquaculture feeds and equipment. But the main method of disease introduction is due to movement of contaminated animals. Assessing of the antimicrobial use is a difficult task due to more than 200 aquatic species are
In our world we are surrounded by microorganisms, some are harmless, many are beneficial; they are a part of our normal flora on our skin and in our intestines, providing a barrier against microorganisms that may not be so harmless. It is important, however, to distinguish which microorganisms are potentially pathogenic from those that are not, and when someone does get ill to determine what the organism is so appropriate treatment can be determined.
One of the most commonly shared beliefs about aquaculture is that it has potential to amplify and transfer disease/parasites to wild fish populations, but strict management practices and guidelines have been utilized and supplemented to ensure that US farming operations mitigate current and potential environmental risks associated with aquaculture (NOAA, 2015). Among these practices are regular diver-led inspections to investigate the integrity of nets and net infrastructure, surveillance cameras and even public webcam feeds that monitor the fish farms and in particular monitor efficient use of feed, regular health inspections in efforts to have a head start on disease prevention and detection, and “comprehensive sanitary and biosecurity programs to prevent the introduction and/or spread of pests or diseases from one farm site/cage to another or into the environment.” (NOAA, 2015). Additionally, movements are being made to stop the spreading of disease and to limit oceanic pollution by containing salmon in solid tanks rather than in netting. “In Washington State, Domsea Farms has launched a land-based, freshwater system to produce coho salmon.” (David Suzuki Foundation, n.d.) This method is not only environmentally sound, but it opens up aquacultural boundaries. By containing fish in these large tanks, there is potential for salmon aquaculture to
coli K1 is a key step in the infection process (polin). The intestine of healthy neonates gets colonized by commensal bacteria shortly after birth, but for some individuals this normally harmless process can lead to sepsis, due mainly to the immature immune system of the human neonate (3). The gastrointestinal tract mucosa possesses several defense mechanisms which protect the gut from microbial infection (30). The gastrointestinal barrier is composed of a monolayer of several cell types, including the structural enterocytes, Paneth cells, and goblet cells, which are involved in the secretion of mucus (14, 30,
Prokaryotes are ubiquitous, successfully adapting to diverse environments as well as developing symbiotic relationships with host organisms (Lengeler, Drews, & Schlegel, 1999). Prokaryotes may have both autotrophic and heterotrophic characteristics. A cyanobacteria is photosynthetic, commonly called blue-green algae, and may produce toxins (Crayton, 1993). Bacteria are most commonly associated in the general
Explain two ways you help in preventing the spread of pathogens on a daily basis. (4 Points)
The simulated gastric solution consisted of distilled water containing 0.2% NaCl with its pH adjusted to 1.5 by 5 M HCl; the solution was filter-sterilized using a 0.2 mm filter (Cook et al. 2011; Mokarram et al. 2009; Rao et al. 1989). The assay was initiated by transferring the produced beads (uncoated, coated) to 9 mL of simulated gastric solution; the initial cell concentration was approximately 8.8× 1013 CFU/mL and 2 -6 × 1012 (uncoated, coated beads). The suspension was incubated at 37° C; samples were collected at 0, 60, and 120 min and following the incubation, the beads were removed. Viable cells of each bacterium were then enumerated in triplicates using method described in Section 2.5 and the counts were expressed as mean log CFU/mL.
The abundance of V. vulnificus in coastal water was strongly correlated to water temperature. The isolation of cultivable forms is limited to the warmest months. Maugeri TL et al reported that V. vulnificus was isolatd only when the water temperature was between 20 to 21.5°C (Maugeri et al. 2006). In the present study, the bacterium was isolated during the summer season (average water temperature of 25°C). It seems that this finding can show association of the cultivable forms on high water temperature. In the current research, V. vulnificus was not found in any samples obtained in the spring (average water temperature of 15°C). In the Gulf of Mexico V. vulnificus was not isolated when seawater temperatures were <14°C (Pfeffer et al. 2003).When the water temperatures reach to less than 13°C, V. vulnificus strains enter the VBNC state in which they are metabolically active but unable to reproduce on common culture media (Nowakowska and Oliver 2013, Wu et al. 2016). In conclusion, with regard to the presence of V. vulnificus in the area under study, the bacterium may cause disease in swimming who have open
These bacteria play a significant role in our health and they are subject to selection from changing human cultures and environments. For example, in the guts of Japanese individuals who eat sushi a gene producing an enzyme, which aids marine bacteria break down the cell wall of seaweed algae, has been found. This is an important example of gene exchange among bacteria giving a selective advantage to
Many residents of the microbiota have the ability to become opportunistic pathogens if there is a breach into internal host territory. For this reason, there are two methods utilized by the host that can be described as a confinement of microbes to intestinal regions and the stratifying of this region to prevent direct contact to host cells as a means of protection. The presence of a layer of intestinal epithelial cells coupled with the secretion of glycoproteins from goblet cells to produce a mucus layer and antimicrobial proteins to disrupt cell membrane are components of the primary barrier in defense. Additionally, stratification creates distinct layers within the intestinal region through the production of IgA antibodies by B cells which can be placed on the apical side of epithelial cells to further prevent entry by binding to bacteria in the lumen (Hooper 2012). An additional mechanism of IgA consists of the decreasing of flagellin gene expression in bacteria in order to reduce host inflammatory responses to cells comprised of flagellin. The secretion of IgA is involved in various functions that regulate the healthy growth of resident commensals to maintain both the diversity and interaction of the gut microbiota with the host
The molluscs comprises of the large phylum of invertebrates known as Mollusca. They are the largest marine phylum and make up approximately 23% of all marine organisms. According to Tripp (1960), molluscs possess a very effective immune system. This immune system is extremely important as it has an immediate defense against infections and microorganisms that invade its body. There are three cellular reactions that are used during internal defense in the molluscs namely; phagocytosis, nodule formation, and encapsulation. Encapsulation or nodule formation is used to handle large invaders while smaller ones are tackled by phagocytosis. Studies have shown that encapsulation is mostly used during an invasion by pathogens. Hemocytes, which replace blood in invertebrates, also have an important function in destroying these pathogens.
Antimicrobial resistant bacteria in seafood are a major public health concern worldwide. Reports on use of antimicrobials in aquaculture and residue findings in the products have indicated food safety threat to the consumers. In aquaculture, the use of wide array antimicrobials leading to development of bacterial resistance, use of resistant probiotic resistant strains and contamination of resistant pathogenic bacteria e.g. Salmonella spp. as input have facilitated to development of pool of resistant bacteria. Indicator bacteria are a useful tool to monitor antimicrobial resistance in any animal originated products. E. coli and Enterococci have been proven useful bacterial indicators in livestock and other animal husbandry practices
One of the cardinal features of mucosal immunity in mammals is the synthesis and transepithelial transport of large amounts of SIgA that contribute to maintaining homeostasis with the enteric microbiota (Macpherson et al., 2008; Mestecky, 1987). Endogenous SIgA production normally begins shortly after weaning, coincident with a shift from breast milk to solid food as the main nutrition source and accelerated colonization of the intestine by commensal bacteria. The initial endogenous SIgA response is dominated by IgA antibodies with few if any mutations in their variable regions and low avidity for the bacteria in the lumen (Lindner et al., 2012). As the mucosal immune system matures, most of the SIgA antibodies secreted in the intestine carry mutations concentrated in the complementarity-determining regions of VH and VL domains. These mutations occur as a result of T-cell dependent somatic mutation in GCs and lead to increased avidity of the antibodies for target antigens. B cell clones responding to foreign antigens that persist can undergo additional rounds of somatic mutation in GALT GCs contributing to further increases in antibody affinity (Bergqvist et al., 2013).