Feeding on dinoflagellates by intermediate and late stage crab zoeae raised in the laboratory and collected from the field

Hatching stage crab larvae will ingest algae, including non-toxic and toxic dinoflagellates. We determined that later zoeal stages, obtained from both laboratory-raised larvae and natural assemblages, also ingest dinoflagellates and we measured the effects of prey density, prior feeding history and time of exposure to prey on incidence of ingestion. Both stage 1 and later stage larvae exposed to algal prey were examined using epifluorescence for the presence of chl a. Both stage 1 and stage 3 laboratory-raised Cancer oregonensis (Dana) and Hemigrapsus nudus (Dana) ingested both the non-toxic dinoflagellate Prorocentrum micans Ehrenberg and the toxic Alexandrium andersoni Balech, with no difference between the stages. Both species showed higher ingestion of P. micans than A. andersoni. Ingestion of both prey types occurred at prey densities as low as 200 cell ml^− 1 in C. oregonensis and 50 cells ml^− 1 in H. nudus. Samples collected in summer, 2004, provided both stage 1 and late stage Lophopanopeus bellus (Stimpson); stage 1, intermediate, and late stage Fabia subquadrata Dana; and an unidentified porcellanid. Stage 1 L. bellus ingested both prey, while late stage zoeae did not, although the latter apparently were not actively feeding. F. subquadrata fed on both prey, with no difference between early and late larvae. Both stages ingested P. micans more readily than A. andersoni. First evidence of ingestion of P. micans at 600 cells ml^− 1 occurred after only 0.5 h, while it took 2 h for ingestion at 50 cells ml^− 1. The model of larval feeding involving both omnivory and prey discrimination described previously for the hatching stage is sustained throughout zoeal development and is, perhaps, an adaptation to an uncertain prey environment, one that trades opportunism for inefficiency.     

Relative Sensitivities of Viruses to Different Species of Interferon

Some viruses were found to be more sensitive than others to the action of interferons from certain species of animals but less sensitive to interferons from other species. Vaccinia virus was the most sensitive to mouse and hamster interferons of five viruses tested, but the least sensitive of these five viruses to human, rabbit, and bat interferons. The relative sensitivities of the viruses to interferons were found to be characteristic for each of the species tested, with those closely related phylogenetically exhibiting similar patterns of relative interferon-induced virus resistance. The amount of synthetic double-stranded polynucleotide polyinosinic acid-polycytidylic acid required to induce resistance to each of the viruses in each of the cell species correlated with the interferon sensitivities of the viruses.     

Intracellular Production of Brucella L Forms I. Recovery of L Forms from Tissue Culture Cells Infected with Brucella abortus

Hatten, Betty A. (The University of Texas Southwestern Medical School, Dallas), and S. Edward Sulkin. Intracellular production of Brucella L forms. I. Recovery of L forms from tissue culture cells infected with Brucella abortus. J. Bacteriol. 91:285-296. 1966.-Infectivity of virulent Brucella abortus strain 3183 was less for hamster macrophages after a 2-hr adsorption period than for an attenuated strain (S19) and its tissue culture variant (30). Both strains S19 and 30 were very toxic for the cells, but 3183 was not toxic. Two types of L forms were recovered from a large percentage of hamster kidney cell cultures when disintegration of infected cells was accelerated by tissue culture medium of high pH. One type grew in finely granular microcolonies, was isolated from cells infected for short periods of time, and often reverted to the bacterial form. The other type occurred in small irregularly shaped forms which later developed into round bodies. Both stained specifically with fluorescein-conjugated B. abortus antiserum. Semisolid media containing 0.7% agar provided optimal subsurface L-form growth. L forms also grew well in Thioglycollate Medium but grew poorly in other liquid media. Surface L-form growth was supported by several agar media, but CO(2) was required for optimal growth. Monolayers infected with strain 3183 and examined immediately after adsorption contained occasional small, round bodies. Bizarre forms increased in number with time and, after 24 to 72 hr, large pink-staining inclusions were often present which persisted for several days. Also appearing at about the same time were smaller, dark-staining forms which were first seen in clusters but later dispersed and finally occurred in chainlike configurations. Direct fluorescent-antibody stains of infected cells established that the intracellular forms were related to the infecting strain of B. abortus.     

Optical Mapping of Action Potentials and Calcium Transients in the Mouse Heart

The mouse heart is a popular model for cardiovascular studies due to the existence of low cost technology for genetic engineering in this species. Cardiovascular physiological phenotyping of the mouse heart can be easily done using fluorescence imaging employing various probes for transmembrane potential (V_m), calcium transients (CaT), and other parameters. Excitation-contraction coupling is characterized by action potential and intracellular calcium dynamics; therefore, it is critically important to map both V_m and CaT simultaneously from the same location on the heart^1-4. Simultaneous optical mapping from Langendorff perfused mouse hearts has the potential to elucidate mechanisms underlying heart failure, arrhythmias, metabolic disease, and other heart diseases. Visualization of activation, conduction velocity, action potential duration, and other parameters at a myriad of sites cannot be achieved from cellular level investigation but is well solved by optical mapping^1,5,6. In this paper we present the instrumentation setup and experimental conditions for simultaneous optical mapping of V_m and CaT in mouse hearts with high spatio-temporal resolution using state-of-the-art CMOS imaging technology. Consistent optical recordings obtained with this method illustrate that simultaneous optical mapping of Langendorff perfused mouse hearts is both feasible and reliable.     

A comparison of two diets in the laboratory culture of the zoeal stages of the brachyuran crabsRhithropanopeus harrisii andNeopanope sp.

Summary 1. The zoeal stages ofRhithropanopeus harrisii andNeopanope sp. (Family Xanthidae) were raised in the laboratory on a diet of proven value,Artemia salina nauplii, and an experimental diet, the rotiferBrachionus plicatilis.2. Survival to the megalopa was achieved on both diets for both species; however, survival was significantly lower for rotifer-fed larvae. Rotifer-fedNeopanope sp. larvae showed lower percent survival of control (A. salina nauplii) than did rotiferfedR. harrisii larvae.3. Delay in molting was immediately apparent in both species when fed rotifers. Intermolt duration was significantly longer for rotifer-fed larvae for all zoeal instars inR. harrisii and in the first two zoeal stages ofNeopanope sp.4. The results are compared with similar studies previously reported for the portunid crabCallinectes sapidus.

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Ein Vergleich zweier Ernährungsformen bei der Laboraufzucht von Zoëa-Stadien der brachyuren KrebseRhithropanopeus harrisii undNeopanope sp.

Kurzfassung Wenn Nauplien des SalinenkrebsesArtemia salina Zoëa-Stadien vonRhithropanopeus harrisii undNeopanope als Nahrung geboten werden, vollzieht sich die Metamorphose zum Megalopa-Stadium bei einem wesentlich größeren Prozentsatz der Larven als bei Verfütterung des RotatorsBrachionus plicatilis. Die Häutungsfrequenz der Larven beider Krebsarten ist verlangsamt, wenn die Zoëen ausschließlich mitBrachionus plicatilis ernährt werden. Die unterschiedlichen Ansprüche an die qualitative Beschaffenheit des Futters, die bei den Larven verschiedener Decapoden zu verzeichnen sind, werden erörtert. Die anRhithropanopeus harrisii, Neopanope sp. sowie anCallinectes sapidus gewonnenen Befunde weisen darauf hin, daßBrachionus plicatilis als alleiniger Futterorganismus für die Aufzucht von Decapodenlarven nicht geeignet ist.

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Contribution No. 696 from the Center for Environmental and Estuarine Studies, University of Maryland.