Euprymna Berry, 1913 - Hawaiian Bobtail Squid

DWhatley

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An Atlas of the Brain Development of Euprymna scolopes to the Hatching Stage
A Galat - 2007 (full PDF)

ABSTRACT
The Mollusca are one of the largest and most diverse phyla of the animal kingdom, comprising
of classes that include bivalves, snails, and cephalopods. Molluscs also display a broad spectrum of
nervous system organization from a primitive protostome level to highly advanced nervous systems
that have been compared to vertebrates in their function. Cephalopods represent the pinnacle of this
advancement. Whilst some inroads have been made concerning molecular correlates of molluscan
development, the embryonic development of the cephalopod brain has not been examined extensively.
The specific aim of this project was to document the anatomy and embryonic development of the brain
of the model organism, Euprymna scolopes, endemic to the coastal waters of Hawaii. A number of
methodological approaches were taken to visualize the embryonic nervous system, including
immunological probes specific for neuronal cell components in combination with laser confocal
microscopy of wholemounts, and conventional histology of late embryonic stages up to the hatching
stage. Comparison of the anatomy of the nervous system of Euprymna scolopes with published reports
of two teuthoid cephalopods during the later developmental stages shows that the formation is similar
in its developmental progression.
 

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Identifying the Cellular Mechanisms of Symbiont-Induced Epithelial Morphogenesis in the Squid-Vibrio Association
Tanya Koropatnick, Michael S. Goodson, Elizabeth A. C. Heath-Heckman, Margaret McFall-Ngai 2013 (PDF)

Abstract
The symbiotic association between the Hawaiian bobtail squid Euprymna scolopes and the luminous marine bacterium Vibrio fischeri provides a unique opportunity to study epithelial morphogenesis. Shortly after hatching, the squid host harvests bacteria from the seawater using currents created by two elaborate fields of ciliated epithelia on the surface of the juvenile light organ. After light organ colonization, the symbiont population signals the gradual loss of the ciliated epithelia through apoptosis of the cells, which culminates in the complete regression of these tissues. Whereas aspects of this process have been studied at the morphological, biochemical, and molecular levels, no in-depth analysis of the cellular events has been reported. Here we describe the cellular structure of the epithelial field and present evidence that the symbiosis-induced regression occurs in two steps. Using confocal microscopic analyses, we observed an initial epithelial remodeling, which serves to disable the function of the harvesting apparatus, followed by a protracted regression involving actin rearrangements and epithelial cell extrusion. We identified a metal-dependent gelatinolytic activity in the symbiont-induced morphogenic epithelial fields, suggesting the involvement of Zn-dependent matrix metalloproteinase(s) (MMP) in light organ morphogenesis. These data show that the bacterial symbionts not only induce apoptosis of the field, but also change the form, function, and biochemistry of the cells as part of the morphogenic program.
 
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Bacterial Symbioses and the Innate Immune Response of the Model Host: Euprymna scolopes
Doctorial Thesis Andrew J. Collins 2014

All animals enter into beneficial relationships with bacteria. The light organ of the Hawaiian Bobtail squid, Euprymna scolopes, is a unique model for studying the establishment and maintenance of a symbiosis between a host and a single bacterial species, Vibrio fischeri. This bacterium inhabits a specialized structure known as the light organ and provides counter-illumination to mask the silhouette of the predator as it hunts for food during the night. Hemocytes, the primary innate immune cells, eferentially bind and phagocytose non-symbiotic at higher rates than their symbiont, but this can change with the colonization state of the animal. A goal of this work was to use high-throughput sequencing to identify genes expressed within hemocytes of adult animals. Of the many genes identified was a novel peptidoglycan recognition protein, EsPGRP5, which is one of the most abundant transcripts in circulating hemocytes. In addition to the light organ, female squid have an accessory nidamental gland (ANG) which contributes to making the jelly coat that covers the squid’s eggs. This gland is full of epithelium-lined tubules, most of which support a dense population of bacteria. Unlike the light organ owever, the bacterial population in the ANG is a consortium of several species, not just one. This work characterized the bacterial symbionts within the ANG and showed that the population is partitioned, with certain tubules containing a single taxon. ...
 

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Squid houses bacteria to keep its eggs safe
Science Magazine Elizabeth Pennisi 18 September 2015 11:45 am

WASHINGTON, D.C.—No bigger than a thumb, the Hawaiian bobtail squid needs all the help it can get to survive. Researchers have long known that this cephalopod, Euprymna scolopes, houses bioluminescent bacteria in a special light organ just for that purpose. The light helps camouflage the squid from predators below, and the squid has specific proteins to aim this spotlight. Now, researchers have discovered that the bobtail hosts other bacterial guests as well—and may depend on them to keep squid eggs safe. Many octopuses watch over their eggs as they develop. Not the bobtail squid, which leaves its eggs unattended on coral reefs. Yet it does have a small gland in its reproductive tract whose function has been a mystery for almost a century. Curious about this gland, microbiologists isolated DNA from it, identifying about a dozen types of microbes. These microbes are deposited in the jelly encasing the squid’s eggs. Now, the researchers have treated bobtail squid eggs with antibiotic and left them in seawater. In just 11 days, the eggs became coated with a “fuzz” of fungi and suffocated, they reported this week at the Frontiers in Phylogenetics meeting at the National Museum of Natural History here. Further tests show that some of the bacteria in the gland are very similar genetically, but have different abilities to inhibit fungi and seem to do a good job keeping eggs clean. Thus, aside from being an unusual example of a host tapping different bacteria for different purposes, the egg-protecting microbes may offer new opportunities to look for novel antifungal compounds.
 

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Nature’s Cutest Symbiosis: The Bobtail Squid | I Contain Multitudes
The bobtail squid is an underwater delicacy for many predators, so the creature found a handy superpower to stay alive: Invisibility. This squishy species is no bigger than a golf ball, making the squid a tasty mouthful for any hungry hunter that feeds along the coastal waters of Hawaii. To avoid becoming a snack, the bobtail squid has formed a powerful alliance with a luminous bacteria called Vibrio fischeri. The bacteria reside inside a “light organ” on the underside of the squid, and at nighttime, these tiny tenants will glow to match the pattern of moonlight coming from above. This helps mask the silhouette of the squid, rendering them “invisible” to predators from below. Ed Yong talks with Margaret McFall-Ngai and Edward Ruby from the University of Hawaii, who have been studying the partnership between the bobtail squid and its glowing microbes for years. A spectacular feature of this symbiosis is that squid aren’t born with a complete light organ—the bacteria help build it!
 

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How to Wake Up a Geriatric Squid - Poking it a little helps
Atlas Obscura Natasha Frost March 14, 2018
...
At the University of Connecticut, scientists are studying how the squids’ immune cells recognize these good bacteria from the thousands of species of other microbes floating around in the seawater. It’s intricate work—lots of squinting through microscopes—and often requires using samples of blood, drawn from the squid who live in the lab. And for that, scientist Sarah McAnulty explains, the squids must be anesthetized for a minute or two. “It’s way less stressful for the animal to be knocked out,” she says.
...
 

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