An improved understanding of the anchialine ecosystem and geology warrants a redefinition of the term 'anchialine.' Originating from subareal biological observations, the term anchialine now ...encompasses chemical, physical, geological and biological elements within the subterranean realm. We propose a more accurate definition of the term anchialine as 'a tidally-influenced subterranean estuary located within crevicular and cavernous karst and volcanic terrains that extends inland to the limit of seawater penetration.' This subterranean estuary is characterized by sharp physical and chemical stratification and merges with a marine system at the coast and a groundwater system inland. The anchialine ecosystem supports a relatively diverse biotic assemblage of stygobiotic species of marine origin dominated by members of Crustacea, both numerically and by species richness.
Numerous studies have shown that hypogean organisms have a reduced metabolism when compared with their epigean counterparts. Although the cause of this metabolic cave adaptation is still uncertain, a ...current theory holds that it results from a reduced oxygen environment. This study examines the metabolism of specimens collected from the Túnel de la Atlántida, Lanzarote, Canary Islands, the completely submerged, seaward-most segment of a 7-km-long lava tube. Unlike many cave systems, the Túnel de la Atlántida is an oxic environment. Invertebrate metabolism was examined directly by measuring oxygen consumed by the organisms. When compared to two suboxic to anoxic anchialine limestone cave systems in the Bahamas, the Lanzarote invertebrate oxygen consumption rates were significantly greater. Amphipods of the genus
Spelaeonicippe
(family Pardaliscidae) found in the Túnel de la Atlántida and in anchialine caves in the Bahamas were compared based upon mass, with
Spelaeonicippe buchi
from Lanzarote being significantly larger than
S. provo
from the Bahamas. The selective pressures of living in a reduced oxygen environment that have forced the Bahamian amphipods to be smaller are released in the oxic environment of the Lanzarote lava tube, allowing for greater body mass and potentially increased clutch sizes.
Stygobites have morphological, ethological and physiological adaptations for their subterranean existence. Included in the physiological adaptations of hypogean organisms is a reduced metabolism with ...respect to related epigean organisms. Our objectives were to examine the physiological adaptations of the shrimp,
Barbouria cubensis
, to the anchialine environment through the use of energetics.
Barbouria cubensis
were collected from oxic anchialine pools in the Bahamas and from a dysoxic cave system in the Yucatan Peninsula of Mexico. Metabolism was addressed via direct measurement of oxygen consumption using microcathode oxygen electrodes as well as the activities of three primary metabolic enzymes, citrate synthase (CS), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH). Additionally, protein and lipid content were determined. Respiration rates of the
B. cubensis
from the oxic environment were lower than reported values for other epigean crustaceans but greater than reported values for stygobitic crayfish. The specimens collected from the dysoxic environment in the Yucatan differed significantly (
p
< 0.01) from the specimens collected in the oxic environment in oxygen consumption, enzyme activities, and lipid concentration. Enzymes of
B. cubensis
from both sites were anaerobically poised with LDH activities exceeding those of CS in all organisms. But in the Yucatan
B. cubensis
, LDH activities exceeded MDH activities. Percent protein did not vary significantly between the two systems.
Barbouria cubensis
provided us with an opportunity to examine the process of cave colonization by looking at the metabolism of specimens in a dysoxic environment and those residing in oxic, surface pools.
This study addresses the causes of the metabolic depression observed when examining the metabolism of hypogean versus epigean organisms. We examined the two current hypotheses regarding the cause of ...metabolic cave adaptation, a paucity of food and low oxygen availability, both necessary for ATP production, by first determining if the hypogean environment examined, Edwards Aquifer, was resource limited. Stable isotope analyses indicate that there is extensive microbial chemolithoautotrophic production providing resources for the hypogean organisms. δ13C values (≤30‰ )were well below that of terrestrial biome indicating that C in the aquifer originates from chemolithoautotrophic inorganic carbon fixation, not photosynthetically derived material resulting from terrigenous sources. Data suggest the artesian system is a complex geochemical ecosystem providing inorganic energy sources from both methane and sulfates. Metabolism, examined via key aerobic and anaerobic proxies, and organismal proximate composition indicated there was no difference between metabolic rates and energy storage of Palaemonetes antrorum (stygobitic) and Palaemonetes kadiakensis (epigean). This indicates that resources within the oxic aquifer are not limited. We demonstrate that it is necessary for one, or both, of these selective pressures to be present for metabolic cave adaptation to occur.
Virtually all species of Hyperiidea have a symbiotic relationship with gelatinous zooplankton. It has been theorized that hyperiid amphipods are descendants of benthic crustaceans that have developed ...a unique benthic-like existence on the pelagic substratum provided by gelatinous zooplankton. But does this strategy have hidden metabolic costs? Metabolism, in the form of both direct respiration and enzyme activities, and proximate composition of Phronima were compared to pelagic and benthic crustaceans. Although less energy is needed to remain in the water column since the gelatinous zooplankton makes the Phronima more buoyant than just Phronima alone, metabolic rates of Phronima are not lower than those of other pelagic crustaceans, possibly due to the energy needed to propel the barrel. However, Phronima have lower protein concentrations, indicating less energy is allocated to muscle production. The ratio of LDH (L-lactate dehydrogenase) activity to CS (citrate synthase) activity was >1, indicating that burst swimming is important in Phronima's metabolism. The symbiotic relationship provides the Phronima with food and a substrate for the brooding of young, but does not give them an energetic advantage over other pelagic crustaceans. /// Pratiquement toutes les espèces d'Hyperiidea ont une association symbiotique avec du zooplancton gélatineux. Une théorie propose que les amphipodes hypériidés descendent de crustacés benthiques ayant développé un mode de vie unique, proche d'une existence benthique, en utilisant le substrat pélagique constitué par le zooplancton gélatineux. Mais cette stratégie a-t-elle des coûts métaboliques cachés? Le métabolisme de Phronima, évalué par l'ensemble respiration et activités enzymatiques et la composition du corps de cet amphipode ont été comparés à ceux de crustacés pélagiques et benthiques. Bien que moins d'énergie soit nécessaire pour rester dans la colonne d'eau puisque le zooplancton gélatineux augmente la flottabilité de Phronima, par comparaison avec des individus isolés, les taux métaboliques de Phronima ne sont pas inférieurs à ceux d'autres crustacés pélagiques, peut-être à cause de l'énergie nécessaire à la propulsion du tonneau. Cependant Phronima a une plus faible concentration protéique ce qui montre que moins d'énergie est alloué à la production de muscle. Le rapport entre l'activité de la LDH (L-lactate déshydrogénase) et l'activité de la CS (citrate synthase) était >1, indiquant l'importance de la nage brusque dans le métabolisme de Phronima. L'association symbiotique fournit à Phronima de la nourriture et un substrat pour l'incubation des jeunes, mais il ne leur confère pas d'avantage énergétique par rapport à d'autres crustacés pélagiques.
Green or shore crabs, Carcinus maenas, exhibit a range of coloration from green through orange to red. Crabs turn red when they delay molting. This phenomenon is hypothesized to be part of a strategy ...in which crabs delay molting in order to allocate resources to reproduction. Thus a more complete understanding of the biology of C. maenas must take coloration into account. In part because of the inconsistency inherent in using subjective descriptions of color, in most studies, crabs which are not clearly "green" or "red" are either ignored or forced into one or the other category. Information about the intermediate individuals is lost. In an attempt to find a reliable, inexpensive, easy-to-use method of quantifying color variation in the field, a color index was developed using paint swatches. The index has been field tested for inter-observer reliability and found to be consistent between both trained and untrained observers, to distinguish quantitatively between subjective color groupings, and to be useful across geographically distinct populations. This kind of index allows, for the first time, a way to quantify color in C. maenas. /// Le crabe vert ou crabe enragé Carcinus maenas, présente une gamme de couleur du vert au rouge en passant par l'orange. Les crabes deviennent rouges quand ils tardent à muer. Ce phénomène est interprété comme une partie de la stratégie par laquelle les crabes retardent leur mue dans le but d'assurer des ressources pour la reproduction. Ainsi, une compréhension plus complète de la biologie de C. maenas doit tenir compte de la couleur. En partie à cause de l'inconsistance inhérente à l'usage de descriptions subjectives de la couleur, dans la plupart des études, les crabes qui ne sont pas clairement "verts" ou "rouges" sont soit ignorés, soit placés dans l'une ou l'autre catégorie. L'information sur les individus de coloration intermédiaire est perdue. Afin de trouver une méthode fiable, bon marché et facile à utiliser pour quantifier la variation de couleur sur le terrain, une gamme de couleurs a été mise au point en utilisant des échantillons de peintures. Cette gamme a été testée sur le terrain pour évaluer sa fiabilité en fonction des observateurs et a été trouvée cohérente, à la fois chez les observateurs entraînés et non-entraînés, pour distinguer quantitativement les groupements de couleurs subjectifs, et s'est avérée utile pour des populations géographiquement distinctes. Ce genre de gamme permet, pour la première fois, de quantifier la couleur chez C. maenas.
Subterranean estuaries formed within carbonate deposits in the paleodrainage systems of Western Australia are habitats for a great diversity of stygiobitic beetles, some of wich are sympatric sister ...species. This study examines the metabolism of stygiobiont beetles using respiration and key metabolic enzymes to determine whether sympatric sister species differ in energy allocation and respiration.
Subterranean estuaries formed within carbonate deposits in the paleodrainage systems of Western Australia are habitats for an great diversity of stygiobitic beetles, some of which are sympatric ...sister species. This study examines the metabolism of stygiobiont beetles using respiration and key metabolic enzymes to determine whether sympatric sister species differ in energy allocation and respiration.
Cytomegalovirus (CMV) causes clinically important diseases in immune compromised and immune immature individuals. Based largely on work in the mouse model of murine (M)CMV, there is a consensus that ...myeloid cells are important for disseminating CMV from the site of infection. In theory, such dissemination should expose CMV to cell-mediated immunity and thus necessitate evasion of T cells and NK cells. However, this hypothesis remains untested. We constructed a recombinant MCMV encoding target sites for the hematopoietic specific miRNA miR-142-3p in the essential viral gene IE3. This virus disseminated poorly to the salivary gland following intranasal or footpad infections but not following intraperitoneal infection in C57BL/6 mice, demonstrating that dissemination by hematopoietic cells is essential for specific routes of infection. Remarkably, depletion of NK cells or T cells restored dissemination of this virus in C57BL/6 mice after intranasal infection, while dissemination occurred normally in BALB/c mice, which lack strong NK cell control of MCMV. These data show that cell-mediated immunity is responsible for restricting MCMV to hematopoietic cell-mediated dissemination. Infected hematopoietic cells avoided cell-mediated immunity via three immune evasion genes that modulate class I MHC and NKG2D ligands (m04, m06 and m152). MCMV lacking these 3 genes spread poorly to the salivary gland unless NK cells were depleted, but also failed to replicate persistently in either the nasal mucosa or salivary gland unless CD8+ T cells were depleted. Surprisingly, CD8+ T cells primed after intranasal infection required CD4+ T cell help to expand and become functional. Together, our data suggest that MCMV can use both hematopoietic cell-dependent and -independent means of dissemination after intranasal infection and that cell mediated immune responses restrict dissemination to infected hematopoietic cells, which are protected from NK cells during dissemination by viral immune evasion. In contrast, viral replication within mucosal tissues depends on evasion of T cells.
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