Occurrence ofVibrio and other bacteria on the sea nettle,Chrysaora quinquecirrha

Sixty-two specimens of the sea nettle,Chrysaora quinquecirrha, were caught in the lower Chesapeake Bay, homogenized, and samples plated on a yeast extract-Bay water agar. Bacterial colonies were selected randomly, purified, and tested for 180 characteristics. Computer analysis permitted clustering of the 208 isolates into 15 groups (comprised of 133 strains) plus 75 nongrouped strains which failed to associate with any group at the 70% similarity level. The majority of the isolates (68.8%) wereVibrio species. These included 110 of the grouped strains (forming 12 of the 15 groups) and 33 of the nongrouped strains. The remainder of the isolates were distributed as follows:Pseudomonas (11.6%),Bacillus (8.2%),Flavobacterium (2.4%),Acinetobacter (2.4%),Moraxella (1.9%),Cytophaga (1.9%), Gram-positive cocci (1.4%), and miscellaneous (1.4%). All theBacillus were isolated from a group of moribund nettles and reflect an abnormal condition.Vibrio species predominated in the five catches of healthy nettles, but were distinctly different for each catch.     

Toxinological and immunological studies of capillary electrophoresis fractionated Chrysaora quinquecirrha (Desor) fishing tentacle and Chironex fleckeri Southcott nematocyst venoms

Repeated runs of capillary electrophoresis (CE) were used to study partially-purified jellyfish nematocyst venom protein in concentrations sufficient to perform toxinological assays. Nematocyst venoms from Chironex fleckeri (Cf) and Chysaora quinquecirrha were processed. The CE eluate was divided into quadrants by scanning protein content. The fourth fraction of both jellyfish venoms, contained proteins with the smallest molecular weight components, which were responsible for the highest hemolysins and the humoral and cell-mediated immunological activity. Cytotoxic Cf lethal factor activity against human liver cells was widely dispersed throughout both venoms but more prominent in fraction 4. A V(beta) receptor human T-cell repertoire was not species-specific for either crude or fractionated jellyfish nematocyst venom.     

Dissociation and reaggregation of cells of Chrysaora quinquecirrha (Cnidaria, Scyphozoa)

Cells of scyphistomae, strobilae, and ephyrae were dissociated with trypsin and reaggregated. Clumping was inhibited in low Ca++ and by puromycin, but not by collagenase or sugars. Reaggregates from the oral end of the polyp developed tentacles and mouths first and basal structures later, whereas the opposite sequence occurred with cells from the lower gastric region. Nile-blue-stained cells from hypostome or peduncle did not form specific structures in the reconstructed polyp, but were distributed throughout the animal. Ephyra cell aggregates showed little morphogenesis, whereas cells from presumptive ephyra tissue gave rise to structures with tentacles and multiple oral openings. Mixed reaggregates containing equal proportions of polyp and ephyra cells formed irregular structures with transparent outer layer and opaque inner cell mass, suggesting stage-specific sorting.     

Some properties of liver alkaline phosphatase from the goat Capra hircus.

1. Gel-filtration of an extract from the liver of the local Hausa goat Capra hircus indicated the presence of two molecular forms of alkaline phosphatase (orthophosphoric monoester phosphohydrolase, E.C. 3.1.3.1.). 2. Cellulose acetate electrophoresis showed that the lower-molecular-weight form had a similar electrophoretic mobility to alpha 2-globulin from goat serum, whereas the higher-molecular-weight form had a similar electrophoretic mobility to gamma-globulin. 3. Only the lower-molecular-weight form was detected on electrophoresis of a liver extract which contained some residual n-butanol used in the extraction procedure, whereas dialysed acetone powder obtained from the liver extract contained both molecular-weight forms. 4. The partially purified enzyme showed maximum activity at pH 9.8, and was stimulated by Mg2+. 5. The enzyme was heat-labile, and was competitively inhibited by phosphate ions but uncompetitively inhibited by L-phenylalanine. 6. These results are discussed in terms of the properties of the enzyme from other sources.     

In situ time budgets of the scyphomedusae Aurelia aurita, Cyanea sp., and Chrysaora quinquecirrha

The in situ behavior of three scyphomedusan species was videorecorded by scuba divers in natural daytime lighting with minimalinterference to the medusae. The mean percentage of time thatindividual medusae spent swimming ranged from 93 to 100%. Therewere no significant differences in the percent time spent swimmingbetween life stages of a species (ephyra, adult) or betweenspecies. The predominance of swimming activity by medusae indicatesthat swimming, and hence the creation of fluid motions responsiblefor prey entrainment and capture, plays a widespread functionalrole in feeding by scyphomedusae.     

Some enzymatic properties of vacuolar alkaline phosphatase from yeast

Candida utilis alkaline phosphatase has been detected in vacuoles. Liberation of the vacuoles was carried out by protoplast disruption under isotonic conditions. The polybase DEAE-dextran was used to induce damage to the yeast plasmalemma. The vacuoles were purified by centrifugation on sorbitol-Ficoll gradients. Alkaline phosphatase from a purified fraction of vacuoles was characterized after gel filtration on Sephadex G-200. We have found 15 mU of enzyme activity per 10⁸ vacuoles. This enzyme activity elutes on Sephadex G-200 at a volume-to-void-volume ratio of 1.65. The approximate molecular weight is 1.35×10⁵. TheK_m value forp-nitrophenyl-phosphate is 2.5×10^–3 M. The pH for maximum activity is 8.9, and the enzyme is stable at pH values between 7.0 and 9.0. Rapid inactivation occurs at temperatures above 45°C. The enzyme catalyzes the hydrolysis of phosphomonoester bonds of a wide variety of molecules, especially polyphosphates. Thus, vacuolar polyphosphates are probably the natural substrate of this enzyme. Orthophosphate, arsenate, ethylenediaminetetraacetate, molybdate, and borate act as inhibitors. Fluoride is not an inhibitor, and the activity is not affected byp-hydroxymercuribenzoate. Some metal ions also affect the activity of vacuolar alkaline phosphatase. This may indicate that this enzyme is a metalloprotein.     

Light responses and die1 migration of the scyphomedusa Chrysaora quinquecirrha in mesocosms

We present evidence of a strong response to light by Chrysaoraquinqueirrha, the common sea nettle, based on studies in largeenclosures (mesocosms). This result is somewhat unexpected dueto the reported absence of light-sensing ocelli in marginalsense organs of this scyphomedusan jellyfish. We used 5-m-deepmesocosms to document light responses and vertical migrationof C.quinquecirrha in both natural and manipulated light fields.Chrysaora quinquecirrha appear to be negatively phototactic;a large fraction of the population always rose towards the surfacewithin 10–15 min after the mesocosms were covered to excludelight, and descended just as quickly when they were uncovered.When natural daylight entering the mesocosms was unaltered,C.quinquecirrha exhibited a consistent pattern of die1 verticalmigration during 1–3 week experiments. Medusae remainedat depth during the day and rose to the surface (top 1 m) ofthe mesocosms during late afternoon. Medusae were abundant atthe surface during most of the night. When at the surface, themedusae characteristically aggregated in very dense swarms of30–50 individuals. In continuous artificial darkness,the medusae gradually increased their numbers at the surfacethroughout the daytime hours, indicating an endogenous componentto the migration. We did not attempt to document diel verticalmigration for the medusae in the field, but the presence ofthis behavior in the mesocosms clearly indicates the abilityof C.quinquecirrha to perceive and respond to light.     

Macrobenthic Communities of the Lower Chesapeake Bay. II. Lynn-haven Roads,Lynnhaven Bay,Broad Bay,and Linkhorn Bay

Based on 96 grab samples at 16 sites the composition and distribution of macrobenthic fauna were examined in a small coastal basin of lower Chesapeake Bay. Normal classification analysis of dominant species produced five site groups. Site groups were divided into clean sand sites, fine sand sites with varying amounts of silt-clay, and mud sites. Dominant species of the clean group were primarily restricted to this sediment type, while the dominant species of the other groups were widespread in the study area.     

Phytoplankton production,biomass and community structure following a summer nutrient pulse in Chesapeake Bay

Unusually high concentrations of NH₄⁺ (up to 10 μM) were observed in the surface waters of polyhaline Chesapeake Bay during July 2000, supporting elevated rates of simulated in situ integrated primary production (4.6 g C m⁻² day⁻¹) and chlorophyll-a (chl-a) specific integrated primary production (56 mg C mg chl-a⁻¹ day⁻¹). These rates were the highest measured in the polyhaline Bay during a 5-year sampling program. Chl-a and the percent contribution of phytoplankton >20 μm to the total phytoplankton increased after the ammonium pulse. We hypothesize that increased wind-driven mixing and a tilting of the pycnocline caused by northeast winds combined to increase the transport of NH₄⁺ from below the pycnocline to the surface water. Summer wind and chl-a data collected in the southern Bay between 1984 and 2000 revealed that chl-a was significantly higher 2 weeks after northeast winds than in years when no northeast wind occurred. Episodic peaks in NH₄⁺ and primary productivity resulting from wind events lasting only a few days are poorly captured by traditional shipboard surveys, but may be detected if sampling is focused on periods when wind forcing favors enhanced NH₄⁺ transport to the surface waters. This process of introduction of NH₄⁺ to the surface water from sediments followed by enhanced primary productivity may help explain some of the phytoplankton blooms that are observed in the polyhaline Bay and other estuaries during summer months.