The microbial population in the air of cultivation facility of oyster mushrooms

The microbial population in the air of mushroom cultivation facility was studied to understand the population structure and size depending on the cultivation methods and regions. The air contents of ten farmers’ oyster mushroom cultivation facilities in Kyunggi province were sampled. The results indicated that there was no difference in population size depending on the regions of mushroom cultivation. In addition, the population size of bacteria in the growth room was bigger than that of the cooling room and outside of the mushroom house, but the fungal population was similar in size between cultivation stages. With regard to population structure, Pseudomonas and Penicillium species were most frequently isolated from the air of oyster mushroom cultivation facility.     

Use of extracts from oyster shell and soil for cultivation of Spirulina maxima

Calcium ion and trace metals play important roles in various metabolisms of photosynthetic organisms. In this study, simple methods were developed to extract calcium ion and micronutrients from oyster shell and common soil, and the prepared extracts were tested as a replacement of the corresponding chemicals that are essential for growth of microalgae. The oyster shell and soil were treated with 0.1 M sodium hydroxide or with 10 % hydrogen peroxide, respectively. The potential application of these natural sources to cultivation was investigated with Spirulina maxima. When compared to standard Zarrouk medium, the Spirulina maxima cultivated in a modified Zarrouk media with elements from oyster shell and soil extract exhibited increases in biomass, chlorophyll, and phycocyanin by 17, 16, and 64 %, respectively. These results indicate that the extracts of oyster shell and soil provide sufficient amounts of calcium and trace metals for successful cultivation of Spirulina maxima.     

HLA gene and haplotype frequencies in galicia (NW Spain)

The genetic structure of six populations of Iran (Turks, Kurds, Lurs, Zabolis, Baluchis and Zoroastrians) was examined using data on blood groups, serum proteins and cell enzymes. Our results show conclusively that there are genetic differences among the six populations and the analysis of superimposed R and S matrices defined by Harpending & Jenkins (1973) show that the dispersion of some of the alleles correspond to the dispersion of the populations. The F_ST estimates are not large enough to favour selection on any of the loci studied. The F_IT and F_IS estimates are positive and moderately high suggesting that the genetic differentiation to some extent is influenced by inbreeding.     

The role of Ulva spp. as a temporary nutrient sink in a coastal lagoon with oyster cultivation and upwelling influence

Bahía San Quintín is a coastal lagoon with large Ulva biomass and upwelling influence. Previous observations suggest that Ulva has increased recently as a result of oyster cultivation. To evaluate the possible role of Ulva as a temporary nutrient sink, biomass and tissue C, N, and P were determined seasonally. Maximum biomass was present during spring and early summer (1,413–1,160 t (dry)) covering about 400 ha. However, the biomass decreased to 35 t (dry) by winter. The mean annual percentage of Ulva C, N, and P was 28%, 2%, and 0.14%, respectively. This study shows that Ulva can store up to 28 t of N and 2 t of P in Bahía San Quintín during spring–summer. Ulva may be displacing the seagrass Zostera marina subtidal beds. A partial removal of the seaweed would reduce the risk of eutrophication and the displacement of eelgrass beds.     

Latitudinal compensation in oyster ciliary activity

1. Theories of latitudinal compensation predict that individuals living in colder temperature regimes should physiologically compensate for the slowing of standard physiological rates, owing to the relatively low temperature of their local environments, by increasing their metabolic rate in colder water temperatures relative to individuals living in warmer water temperature regimes.
2. This hypothesis was tested with oyster strains originally from geographically separated populations that were raised in a common environment for seven generations. The physiological parameter measured was ciliary activity across a temperature gradient.
3. Support for the latitudinal compensation hypothesis was found: the strain originally from the colder temperature regime had more active cilia at lower experimental temperatures than individuals originally from the warmer temperature regime. Ciliary activity of the more northern Long Island Sound oysters was significantly greater than activity in the more southern Delaware Bay oysters at temperatures of –1, 2 and 6 °C.
4. These results suggest that there is genetically based physiological differentiation between these populations of oysters consistent with the latitudinal compensation for local temperature regime.     

A Modular Flat Panel Photobioreactor (MFPP) for indoor mass cultivation of Nannochloropsis sp. under artificial illumination

Nannochloropsis sp. was grown in a Modular FlatPanel Photobioreactor (MFPP) consisting of sixalveolar panels each with 20.5 L culture volume and3.4 m² illuminated surface area. The panelsformed a closely-packed unit with illuminationprovided by banks of fluorescent tubes placed betweenthe panels. The whole unit was contained in athermoregulated cabinet. Continuous illumination ofone side of the panels with 115 molphoton m^-2 s^-1 attained a mean volumetricproductivity of 0.61 g (d. wt) L^-1 24 h^-1,increasing to 0.97 g (d. wt) L^-1 24 h^-1 whenthe same irradiance was provided on both sides of thepanels. With 230 mol photon m^-2 s^-1 onone side of the panel, a mean productivity of 0.85 g(d. wt) L^-1 24 h^-1 was achieved, whichreached 1.45 g (d. wt) L^-1 24 h^-1 when bothsides were illuminated. Increasing the amount of lightprovided to the culture (either by increasingirradiance or the illuminated surface area) decreasedpigment and enhanced the total fatty acid content, butdid not change significantly the content ofeicosapentaenoic acid. A MFPP of the presentdimensions could produce sufficient microalgae tosupport a hatchery producing 6 million sea breamfingerlings annually.     

Epizootiology and pathology of juvenile oyster disease in the Eastern oyster, Crassostrea virginica.

Juvenile Oyster Disease (JOD) causes mortalities of small cultured oysters, Crassostrea virginica. The present study was an intensive epizootiological and pathological investigation of JOD in eight sequentially deployed cohorts at sites on Long Island, New York. JOD symptoms and mortalities began in all groups at about the same time. Lesions on the mantle were detected histologically about 1 week before the principal symptom, a conchiolin deposit on the inner shell, appeared. Mortality began about 1 week later and reached 60-90% in oysters <25 mm. Mantle lesions were highly correlated with subsequent conchiolin-deposit prevalence and with total mortality. Larger juveniles (25-40 mm) were affected by the disease and produced conchiolin deposits, but mortalities did not exceed 30%. Mortalities were consistently related to size, but not necessarily to age or length of "exposure" in the field. There was no indication that JOD was linked to a particular broodstock or hatchery. Wild spat deployed at experimental sites showed JOD symptoms before the hatchery-produced groups did and cohorts maintained inside a hatchery experienced essentially no JOD. Histological examination of cohorts experiencing high mortalities failed to reveal an obvious etiological agent, but showed a disease pattern similar to that described for other bivalve diseases with a bacterial etiology. Similarities and differences between this and other studies of JOD suggest that one or more bacterial species is responsible for JOD, but that a trigger, probably temperature, is also involved and may vary from site to site.     

The relationship between the flowering phenophase and airborne pollen of Betula in galicia (N.W. spain)

The aim of this work was to investigate thephenological behaviour of Betula in Galicia, NW Spain, and to examine therelationship between the Betula pollencurves and the flowering phenophase. Threetrees were chosen from the each of ninepopulations of Betula located atdifferent altitudes and phytogeographicpositions. Phenological observations of theflowering periods of Betula were made ineach of them. Environmental factors such asfrequency of mist, latitudinal and topographicposition, proximity of the ocean, degree ofsolar exposure, and altitude result inphenological differences between theinvestigated populations. The correlationbetween the Pollinic Production Index of Betula pollen in Galicia and theaerobiological data of the seven monitoringstations showed that the period in which thehighest concentrations were registered wasalmost synchronous with the flowering times atmost of the phenological stations studied.Other factors such as transport and reflotationshould also be taken into account to provide anadequate interpretation of the aerobiologicaldata of Betula pollen in the atmosphere.     

Inhibition of oyster drill chemotaxis

A bioassay was developed by Rittschof el al. (1983) to examinedistance chemoreception in the predatory marine gastropod, Urosalpinxcinerea. This bioassay was used to test the effect of a senesof low mol. wt. organics on the ability of newly hatched oysterdrills to detect a prey odor released from barnacles, Balanusbalanoides. Two series of low mol. wt. organics were testedusing methanol as the reference compound. In one series, R-OH,the carbon chain length was varied from 1 to 4. In the secondseries, CH³-R, the chain length was held constant while thefunctional group, R, was varied. When these compounds were presentin the rnM range, they inhibited the creeping response of oysterdrills towards barnacle prey odor. In the CH₃-R series, inhibitionincreased in the following order: sodium acetate > ethylacetate > acetonitnle > methanol; and, in the alcoholseries C₁ to C₄, inhibition increased with increasing chainlength. No creeping response was observed when these compoundswere tested in the absence of prey odor.     

Subunit structure of oyster paramyosin

Paramyosin from the oyster Crassostrea commercialis was studied by equilibrium sedimentation. In non-denaturing solvents the minimum molecular weight is 208000. Dissociation into subunits requires complete disruption of the alpha-helix. This occurs at pH7 in guanidine hydrochloride solutions of concentration greater than 7m in the presence of a disulphide-bond-reducing agent. Solutions of the protein in concentrated guanidine hydrochloride are polydisperse and contain species of low molecular weight (approx. 25000) comprising approx. 5% to 10% of the protein. The molecular weight of the main component is estimated to be 97000 and the paramyosin molecule contains two of these subunits. From the present observations no decision can be made as to whether or not the small component (or components) represents part of the paramyosin molecule. Preferential binding of guanidine hydrochloride to the extent of 0.13g./g. of protein was shown in solutions of paramyosin in 7.85m-guanidine hydrochloride.