Oxygen and ammonium dynamics during a farming cycle of the bivalve <Emphasis Type="Italic">Tapes philippinarum</Emphasis>

Fluxes of dissolved oxygen and ammonium across the water sediment interface were measured in a control and in an experimental area farmed with the clam Tapes philippinarum. Young clams were seeded in March 2003 at mean (~500 ind m⁻²) and high (~1500 ind m⁻²) densities in a sandy area (2100 m²) of the Sacca di Goro Lagoon, Italy. Approximately every two months, until October 2003, intact sediment cores were collected and incubated in the light and in the dark and surface sediments (0–2 cm) were analysed for organic matter and nitrogen content. Clams farming induced pronounced changes in sediment characteristics and metabolism. Oxygen consumption and ammonium production at the high density area were, on average, 3 to 4 and 1.9 to 4.9 folds higher than those measured in the control field respectively; rates were positively correlated with clams biomass. Experimental fields resulted “Net and Total Heterotrophyc” in 3 out of 4 sampling dates and clams were the major factor shifting the benthic system towards this status. In only one occasion the appearance of the macroalgae Ulva spp. pushed the system rapidly towards hyperautotrophic conditions. Our results indicated that clams have the potential to drive benthic metabolism in farmed areas and to sustain macroalgal growth through regeneration of a limiting nutrient for seawater as inorganic N.     

Stimulation of sulfate reduction rates in Mediterranean fish farm sediments inhabited by the seagrass <Emphasis Type="Italic">Posidonia oceanica</Emphasis>

Sulfate reduction rates and biogeochemical parameters of fish farm sediments across the Mediterranean were investigated in the order to evaluate the potential effects of organic matter inputs on habitat quality for the common seagrass Posidonia oceanica. Four study sites were selected in Spain, Italy, Greece and Cyprus to represent the Mediterranean basin. P. oceanica was found in immediate vicinity of all the farms, which were located at physically exposed sites about 1 km from the shore lines. Organic matter accumulation, sulfate reduction rates and sulfur pools were measured in depth profiles along transects from the farms in both bare and vegetated sediments. Results show that although the organic matter accumulation was minor at the sites (POC < 2.8% DW), the sulfate reduction rates were high, in particular at the largest farm in Italy (up to 212 mmol m⁻² d⁻¹), similar to rates found at shallower, temperate fish farm sites, where higher sedimentation rates can be expected. Sulfate reducing bacteria in these low-organic, carbonate-rich Mediterranean sediments respond strongly to organic matter loadings and cause habitat degradation. Sulfate reduction rates measured in the P. oceanica sediments were among the highest recorded (7.8–42.0 mmol m⁻² d⁻¹) similar to rates found in degrading meadows impacted by organic matter loadings. As sulfate reduction rates were correlated with the sedimentation rates along the transects rather than organic matter pools this suggests mineralization processes were controlled by organic matter loading in fish farm sediments. The vegetated sediments near the net cages were more reduced due to accumulation of sulfides compared to control sites, which is a possible contributing factor to the observed seagrass decline in the farm surroundings. It is recommended that Mediterranean fish farms are placed in areas with rapid dispersal of particulate waste products to minimize organic matter loading of the sediments and thereby preserve habitat quality for benthic fauna and flora.     

Bioavailability of zinc in the sediment to the estuarine amphipod <Emphasis Type="Italic">Grandidierella</Emphasis><Emphasis Type="Italic">japonica</Emphasis>

The utility of interstitial water concentrations of metals and simultaneously extracted metals/acid-volatile sulfide differences (SEM–AVS) in two seasons were investigated to explain the biological availability of zinc in sediments to benthic organisms exposed in the laboratory. The amphipod Grandidierella japonica was exposed, in 10-day acute toxicity tests, to clean sediment spiked with zinc to obtain nominal treatments ranging from 0.25 to 74.4 mol g^–1 dry weight with respect to the molar difference between SEM_Zn and AVS. When the molar difference between SEM_Zn and AVS (i.e., SEM–AVS) was <0 mol g^–1, the concentration of zinc in the sediment interstitial water was low and few adverse effects were observed for any of the biological endpoints measured. Conversely, when SEM_Zn–AVS exceeded 0 mol g^–1, the concentration of zinc in the interstitial water and amphipod mortality increased. These data compare favorably with observations made in short-term exposures and thus support the use of AVS as a normalization phase for predicting toxicity in metal-contaminated sediments in different season.     

Acute toxicity testing with the European estuarine amphipod <Emphasis Type="Italic">Corophium multisetosum</Emphasis>

This study reports on the use of the estuarine amphipod Corophium multisetosum in acute toxicity testing. The species was successfully acclimated to the laboratory and was used in a water-only whole effluent 96 h acute bioassay and in a 10 days whole estuarine sediment test. C. multisetosum response was compared to other species in 96 h bioassays, testing boiling cork effluent and iron filings lixiviates. The amphipod showed high sensitivity and the results were similar to those obtained with others species namely, the freshwater cladoceran Daphnia magna, the estuarine amphipod Gammarus chevreuxi and the seawater annelid Sabellaria alveolata. In a 10 days static exposure to natural impacted estuarine sediments, the response of the species was compared to a fertilization bioassay with the sea-urchin Paracentrotus lividus. Both species indicated the same sediment samples as the most potentially toxic. These samples were collected in sites where the resident macrofauna benthic community is also the most affected, with strong reduction of the species richness, abundance and biomass. The results revealed that C. multisetosum presents high potential to be used in routine acute toxicity testing in the estuarine environment.     

Acaricidal effects of <Emphasis Type="Italic">Corymbia citriodora</Emphasis> oil containing <Emphasis Type="Italic">para</Emphasis>-menthane-3,8-diol against nymphs of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> (Acari: Ixodidae)

The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results obtained by methods A, C and E, the LC₅₀ range was 0.035–0.037 mg PMD/cm² and the LC₉₅ range was 0.095–0.097 mg PMD/cm² at 4 h of exposure; the LT₅₀ range was 2.1–2.8 h and the LT₉₅ range was 3.9–4.2 h at 0.1 mg PMD/cm². To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm²) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic to nymphs of I. ricinus and may be useful for tick control.     

<Emphasis Type="Italic">Catenaria anguillulae</Emphasis> Sorokin: a Natural Biocontrol Agent of <Emphasis Type="Italic">Meloidogyne graminicola</Emphasis> Causing Root Knot Disease of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Summary Catenaria anguillulae parasitized and killed the eggs and second stage juveniles (J₂) of Meloidogyne graminicola under natural conditions. The percentage of infection in eggs was higher than J₂ of M.␣graminicola, which ranged between 0–50.3% and 0–18.9% in 2004 and 0–46.6% and 0–21.7% in 2005, respectively. The higher parasitism of eggs and J₂ was recorded from those fields in which plants were severely infected with M. graminicola. The degree of parasitism of eggs and J₂ by C. anguillulae varied with severity of root knot disease. The fields with a higher root gall index recorded a higher percentage of infection in eggs and J₂ of M. graminicola. In general, old galls when teased and incubated, recorded higher parasitism of eggs and juveniles than young galls.     

Combined effects of temperature,food (<Emphasis Type="Italic">Chlorella vulgaris</Emphasis>) concentration and predation (<Emphasis Type="Italic">Asplanchna girodi</Emphasis>) on the morphology of <Emphasis Type="Italic">Brachionus havanaensis</Emphasis> (Rotifera)

The combined effect of temperature, food level and the presence of an invertebrate predator on the body size of the rotifer Brachionus havanaensis were tested in this study. B. havanaensis was cultured at 15, 20, and 25°C under three different Chlorella vulgaris levels (0.5 × 10⁶, 1.0 × 10⁶ and 2.0 × 10⁶ cells ml⁻¹) in the presence and in the absence of Asplanchna girodi. For each treatment we maintained three replicates and constant (0.4 ind ml⁻¹) population density of B. havanaensis. In treatments containing A. girodi, the predator was separated from the prey by a mesh (pore size 50 μm). On the last day of the experiment, a portion of the B. havanaensis population was sampled for several morphometric measurements (adult lorica length, width, posterior spine length, body volume, and the egg volume). Size measurements were done by drawing the specimens using a calibrated camera lucida. Statistically significant impact of temperature as well as the predator’s presence was observed on the lorica length, posterior spine, and egg volume of B. havanaensis. The interactions of food × temperature, or predator′s presence × food × temperature were non-significant (P > 0.05) for lorica length, spine length, body volume, and egg volume. Regardless of the type of treatment, there was a direct positive correlation between lorica length and width. Egg volume was linearly related to the adult size. Notably long posterior spines were observed in treatments containing the presence of A. girodi. Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez. Advances in Rotifer Research     

Comparison of conditions for mycelial growth of <Emphasis Type="Italic">Lepista sordida</Emphasis> causing fairy rings on <Emphasis Type="Italic">Zoysia matrella</Emphasis> turf to those on <Emphasis Type="Italic">Agrostis palustris</Emphasis> turf

Symptoms of fairy rings caused by Lepista sordida have been reported on Zoysiagrass (Zoysia spp.) turf maintained at fairway height (2 cm), but not on bentgrass (Agrostis spp.) maintained at putting green height (0.5 cm). The mycelia of this fungus inhabit primarily the upper 0–2 cm layer of the soil extending into the thatch. To compare conditions for the mycelial growth in Z. matrella turf to those in A. palustris turf, we examined the effects of nutrients, temperature, water potential, and pH in the field as well as in the laboratory. Greater growth of the mycelia was observed in medium that included hot water extracts from soil of the 0–1 cm zone in Z. matrella turf compared to that from A. palustris. The upper soil layer in Z. matrella turf contained more organic matter from clippings than that in A. palustris. The temperature and water potential of the 0–2 cm soil zone in Z. matrella turf were also more favorable for the mycelial growth. The soil pH values of this zone in Z. matrella turf were less favorable compared to A. palustris but within the range for accelerating mycelial growth. Part of this study was presented orally at the 46th meeting of the Mycological Society of Japan in 2002     

Persistence of <Emphasis Type="Italic">Paranosema</Emphasis> (<Emphasis Type="Italic">Nosema</Emphasis>) <Emphasis Type="Italic">locustae</Emphasis> (Microsporidia: Nosematidae) among grasshopper (Orthoptera: Acrididae) populations in the Inner Mongolia Rangeland,China

Paranosema (Nosema) locustae Canning has persisted in grasshopper populations in the Inner Mongolia Rangeland since spore treatment was applied in 1993. In the treatment year, a 58.32–71.43% reduction of grasshoppers was recorded and 59.26–80.36% of surviving grasshoppers of various species were infected. In the years following application, prevalence of P. locustae varied from 13.65% to 60.71%, demonstrating that P. locustae remains in grasshopper populations for many years. Infection prevalence was more than 60.00% for Dasyhippus barbipes (F.-W.), Bryodema luctuosum luctuosoma (Stoll) and Angaracris barabensis (Pall.) in 1993 but was very variable, ranging from 20.00% to 60.71% over the subsequent nine years. Disease prevalence was 43.72–60.71% in 1993 and 1994 for Oedaleus asiaticus B.-Bienko and Myrmeleotettix palpalis (Zub.) but gradually declined to approximately 20%, where it remained. Persistence of P. locustae in grasshopper populations may be important in keeping densities below economic thresholds for a number of years after application. Handling Editor: Helen Roy.     

<Emphasis Type="Italic">In vitro</Emphasis> organogenesis of <Emphasis Type="Italic">Pelecyphora aselliformis</Emphasis> erhenberg (cactaceae)

Summary In vitro propagation of Pelecyphora aselliformis, a Mexican cactus which is considered rare and is highly valued in the commercial market, was initiated using seeds as explants. The longitudinal explants from seedlings germinated in vitro were cultivated on Murashige and Skoog medium containing 8.8 μM benzyladenine (BA) or 4.6 μM kinetin at pH 7.0. After 120 d, each explant gave rise to five shoots and this number of shoots increased 20–25% after subculture. The hyperhydricity was similar in both media, but callus formation was lower on the medium with BA. The shoot development, in terms of epicotyl length, and fresh and dry weight after 6 wk, was also recorded. The epicotyl length was similar on shoot-forming media but the quality of shoots was better on media containing BA. In about 1 yr, 500–600 well-defined shoots were obtained. The rooting of shoots was very slow and a vigorous radical system was observed after 1 yr of culture.     

Role of the polychaete <Emphasis Type="Italic">Neanthes succinea</Emphasis> in phosphorus regeneration from sediments in the Salton Sea,California

The Salton Sea currently suffers from several well-documented water quality problems associated with high nutrient loading. However, the importance of phosphorus regeneration from sediments has not been established. Sediment phosphorus regeneration rates may be affected by benthic macroinvertebrate activity (e.g. bioturbation and excretion). The polychaete Neanthes succinea (Frey and Leuckart) is the dominant benthic macroinvertebrate in the Salton Sea. It is widely distributed during periods of mixing (winter and spring), and inhabits only shallow water areas following development of anoxia in summer. The contribution of N. succinea to sediment phosphorus regeneration was investigated using laboratory incubations of cores under lake temperatures and dissolved oxygen concentrations typical of the Salton Sea. Regeneration rates of soluble reactive phosphorus (SRP) were lowest (−0.23–1.03 mg P m⁻² day⁻¹) under saturated oxygen conditions, and highest (1.23–4.67 mg P m⁻² day⁻¹) under reduced oxygen levels. N. succinea most likely stimulated phosphorus regeneration under reduced oxygen levels via increased burrow ventilation rates. Phosphorus excretion rates by N. succinea were 60–70% more rapid under reduced oxygen levels than under saturated or hypoxic conditions. SRP accounted for 71–80% of the dissolved phosphorus excreted under all conditions. Whole-lake SRP regeneration rates predicted from N. succinea biomass densities are highest in early spring, when the lake is mixing frequently and mid-lake phytoplankton populations are maximal. Thus, any additional phosphorus regenerated from the sediments at that time has potential for contributing to the overall production of the lake. Guest Editor: John M. Melack Saline Water and their Biota     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of <Emphasis Type="Italic">Zingiber petiolatum</Emphasis> (Holttum)

Summary We describe an in vitro propagation protocol for Zingiber petiolatum (Holttum), I. Theilade, a rare species from the southern part of Thailand. Fruits were surface-sterilized and seeds germinated on Murashige and Skoog medium (MS) medium supplemented with 3% sucrose. Three-month-old seedlings were used as initial plant material for in vitro propagation. Terminal buds of the plants were inoculated on MS medium containing 6-benzylaminopurine (BA; 2.2–35.5 μM) alone or in combination with 1-naphthaleneacetic acid (0.5 μM). Eight weeks after inoculation, the cultures were transferred to MS medium without plant growth regulators for 4wk. The cultures transferred from MS medium with 17.8 μM BA revealed the highest shoot induction rate of 6.1±0.7 shoots per explant. Rooting was spontaneously achieved in MS medium without plant growth regulators. Rooted plants were successfully transplanted to soil.     

Induction of pathogenesis-related proteins during biocontrol of <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> with <Emphasis Type="Italic">Pseudomonas aureofaciens</Emphasis> in soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L. Merr.) plants

To investigate the biocontrol effectiveness of the antibiotic producing bacterium, Pseudomonas aureofaciens 63–28 against the phytopathogen Rhizoctonia solani AG-4 on Petri plates and in soybean roots, growth response and induction of PR-proteins were estimated after inoculation with P. aureofaciens 63–28 (P), with R. solani AG-4 (R), or with P. aureofaciens 63–28 + R. solani AG-4 (P + R). P. aureofaciens 63–28 showed strong antifungal activity against R. solani AG-4 pathogens in Petri plates. Treatment with P. aureofaciens 63–28 alone increased the emergence rate, shoot fresh weight, shoot dry weight and root fresh weight at 7 days after inoculation, when compared to R. solani AG-4; P + R treatment showed similar effects. Peroxidase (POD) and β-1,3-glucanase activity of P. aureofaciens 63–28 treated roots increased by 41.1 and 49.9%, respectively, compared to control roots. POD was 26% greater in P + R treated roots than R. solani treated roots. Two POD isozymes (59 and 27 kDa) were strongly induced in P + R treated roots. The apparent molecular weight of chitinase from treated roots, as determined through SDS-PAGE separation and comparison with standards, was about 29 kDa. Five β-1,3-glucanase isozymes (80, 70, 50, 46 and 19 kDa) were observed in all treatments. These results suggest that inoculation of soybean plants with P. aureofaciens 63–28 elevates plant growth inhibition by R. solani AG-4 and activates PR-proteins, potentially through induction of systemic resistance mechanisms.     

Overexpression of the <Emphasis Type="Italic">ICL1</Emphasis> gene changes the product ratio of citric acid production by <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis>

The yeast Yarrowia lipolytica secretes high amounts of various organic acids, like citric (CA) and isocitric (ICA) acids, triggered by growth limitation caused by different factors and an excess of carbon source. Depending on the carbon source used, Y. lipolytica strains produce a mixture of CA and ICA in a characteristic ratio. To examine whether the CA/ICA product ratio can be influenced by gene-dose-dependent overexpression or by disruption of the isocitrate lyase (ICL)-encoding gene ICL1, recombinant Y. lipolytica strains were constructed, which harbour multiple ICL1 copies or a defective icl1 allele. The high-level expression of ICL in ICL1 multicopy integrative transformants resulted in a strong shift of the CA/ICA ratio into direction of CA. On glycerol, glucose and sucrose, the ICA proportion decreased from 10–12% to 3–6%, on sunflower oil or hexadecane even from 37–45% to 4–7% without influencing the total amount of acids (CA and ICA) produced. In contrast, the loss of ICL activity in icl1-defective strains resulted in a moderate 2–5% increase in the ICA proportion compared to ICL wild-type strains on glucose or glycerol.     

A new species of <Emphasis Type="Italic">Elaphoglossum</Emphasis> sect. <Emphasis Type="Italic">Lepidoglossa</Emphasis> subsect. <Emphasis Type="Italic">Muscosa</Emphasis> (Dryopteridacae) with cristate spores

A new species from the Bolivian highlands is described as Elaphoglossum cristatum. It is very similar to E. engelii but is characterized by a (for subsect. Muscosa unique) cristate perispore structure with irregular deposits (versus papillate spores), more densely ciliate petiole scales (50–80 versus 10–30 cilia per scale), somewhat thicker blade texture, denser scale cover, and paler, more reddish rhizome scales.     

Diversity of volatile compounds of <Emphasis Type="Italic">afitin</Emphasis>, <Emphasis Type="Italic">iru</Emphasis> and <Emphasis Type="Italic">sonru</Emphasis>, three fermented food condiments from Benin

Volatile compounds in afitin, iru and sonru, three traditional food condiments produced in Benin by natural fermentation of the African locust bean (Parkia biglobosa) were identified and quantified, using the Likens-Nickerson simultaneous distillation-extraction method and GC-MS analysis. A total of 13 chemical groups of volatile compounds were identified and classified in six major groups: pyrazines, aldehydes, ketones, alcohols, esters and benzene derivatives. From these groups, 2,5–dimethylpyrazine, tetramethylpyrazine, 3-methylbutanal, 2-decanone, 3,5-dimethylphenylmethanol, ethyl linoleate and chlorobenzene were found in higher amounts in the three condiments. Afitin was characterized by high concentration of 2-decanone, whereas 2,5-dimethylpyrazine, tetramethylpyrazine, 3-methylbutanal and ethyl linoleate were found particularly in higher concentration, both in iru and sonru.     

Physiological comparison of copper toxicity in the lichens <Emphasis Type="Italic">Peltigera rufescens</Emphasis> (Weis) Humb. and <Emphasis Type="Italic">Cladina arbuscula</Emphasis> subsp. <Emphasis Type="Italic">mitis</Emphasis> (Sandst.) Ruoss

Peltigera rufescens (Weis) Humb. with a prokaryotic photobiont Nostoc sp. and Cladina arbuscula subsp. mitis (Sandst.) Ruoss with a eukaryotic photobiont Trebouxia sp. were studied to determine the copper sensitivity of lichens with different algal symbionts. Samples growing on historic copper mine-spoil heaps at Ľubietová–Podlipa, Slovakia were assessed for physiological parameters, including total and intracellular uptake of copper, assimilation pigmentation, activity of photosystem II, ergosterol levels, thiobarbituric acid reactive substances and water-soluble protein content. Our results indicate that P. rufescens was more sensitive to copper exposure than C. arbuscula subsp. mitis.     

Locomotor activity rhythm and sun compass orientation in the sandhopper <Emphasis Type="Italic">Talitrus </Emphasis><Emphasis Type="Italic">saltator</Emphasis> are related

The sandhopper Talitrus saltator has an endogenous activity rhythm with a circadian periodicity. It is well known for its ability to compensate for the apparent movement of the sun during its migrations along the sea–land axis of the beach. Both chronometric mechanisms are entrained by the natural LD photoperiod. Using actographic recordings and tests of solar orientation of individuals kept under an LD 12:12 clock-shifted cycle, after 1–13 days of treatment, we demonstrate that the timing mechanism of activity rhythm and the chronometric mechanism underlying the sun compass are the same.     

Some aspects of the biology of the amphipods <Emphasis Type="Italic">Ischyrocerus anguipes</Emphasis> associated with the red king crab, <Emphasis Type="Italic">Paralithodes camtschaticus,</Emphasis> in the Barents Sea

This paper describes size composition, morphometric, and reproductive parameters of the summer generation of the amphipod Ischyrocerus anguipes (Krǿyer, 1838) associated with the red king crab Paralithodes camtschaticus (Tilesius, 1815) in Dalnezelenetskaya Bay (southern Barents Sea, Russia). In summer 2004–2007, prevalence and mean number of I. anguipes per host were 15.0% and 6.9 ± 1.1 specimens, respectively. The majority of amphipods were found on the host carapace (47.4%) and the limbs (43.9%). High infestation indices and absence of negative impacts for the host indicate that I. anguipes is a facultative commensal of the red king crab. The amphipods sex ratio was significantly biased toward females (F:M = 2:1). Females had a greater size than males. The size at 50% maturity of I. anguipes females was estimated to be 3.37 mm. The number of eggs laid is linearly correlated with the size of a female. Some differences in biological features of symbiotic and free-living amphipods (data obtained in 1940–1950) may be explained by climatic changes in the Barents Sea or advantages of living on the crab.