Population structure, growth and production of Thoracophelia furcifera (Polychaeta: Opheliidae) on a sandy beach in Southern Brazil

This study investigates aspects of the life history of the polychaete Thoracophelia furcifera on a sandy beach in southern Brazil. Two fixed transects perpendicular to the shoreline in the intertidal zone were sampled fortnightly from May 2008 to April 2009 at low tide. Five T. furcifera samples were collected along each transect and sediment temperature and the salinity of interstitial water were recorded. The material was washed over 0.5- and 0.088-mm sieves, and the width of setiger 8 of each specimen was measured. A total of 5,870 organisms were examined and the estimated parameters of the von Bertalanffy growth curve were L _∞ 3.60?mm (Wd8S), K 0.63?year^?1, C 0.3 and WP 0.97 (Rn 0.132). Life span was 2.6?years, instantaneous mortality rate Z was 3.8?year^?1 and the growth index φ′ 0.91. Mean density ranged from 644.44?±?191.77 to 2,783.33?±?453.64 ind m^?2 and mean biomass ranged from 2.52?±?0.55 to 9.52?±?1.83?g?m^?2. Recruitment occurred from April to July and ovigerous females were found from June to November. Annual secondary production was 6.582?g?m^?2?year^?1, mean biomass was 5.638?g?m^?2 and turnover rate was 1.167. The high values for density, secondary production and biomass suggest that T. furcifera constitute an important food source. These features of T. furcifera’ life strategy demonstrate the significant role this species plays in ecosystem dynamics.     

Distribution, standing stock, growth, mortality and production of Strongylocentrotus pallidus (Echinodermata: Echinoidea) in the northern Barents Sea

The regular sea urchin, Strongylocentrotus pallidus (G.O. Sars, 1871), is a widespread epibenthic species in high-Arctic waters. However, little is known about its distribution, standing stock, population dynamics and production. In the northern Barents Sea, S. pallidus was recorded on seabed still photographs at 10 out of 11 stations in water depths of 80–360?m. Mean abundances along photographic transects of 150–300 m length ranged between <0.1 and 14.7?ind. m^?2 yielding a grand average of 3.6?ind.?m^?2. The small-scale distribution along the transects was patchy, with densities varying from nil to an overall maximum of 25.5 ind. m^?2, and exhibited a significant relation to the number of stones present. Sea urchin test diameters, measured on scaled photographs, extended from 7 to 90?mm. Median values at single stations varied from 14 to 46?mm, showing a significant inverse relationship to water depth. Biomass, estimated by combining photographic abundances, size frequencies and a size-mass function established with trawled specimens, ranged between <0.1 and 3.0?g ash-free dry mass m^?2, averaging about 1.0?g ash free dry mass m^?2. An analysis of skeletal growth bands in genital plates was carried out with 143 trawled individuals ranging in test diameter (D) from 4 to 48?mm. Assuming these bands to represent annual growth marks, the ages of the specimens analysed ranged between 3 and 42 years. A von Bertalanffy function was fitted to size-at-age data to model individual growth pattern (D_∞?=?102.3?mm, k?=?0.011 year^?1, t₀?=?0.633?year). The annual mortality rate Z of the population in the northern Barents Sea was estimated from a size-converted catch curve to be 0.08 year^?1. Applying the weight-specific growth rate method, the average P/B ratio and the mean annual production of this population were estimated as 0.07 year^?1 and 0.076?g AFDM m^?2 year^?1, respectively. In conclusion, S. pallidus is characterized by slow growth, low mortality, high longevity and low productivity. Because of its relatively high biomass, it is considered to contribute significantly to total benthic standing stock and carbon flux in the study area.     

Chromium removal from water by three species of dyckweeds

The effects of exogenous chromium (Cr) on the growth of three species of duckweeds: Spirodela punctata (G.F.W. Meyer) Thomps., Spirodela polyrhiza (L.) Schleiden and Lem na gibba L., were examined at Cr concentrations ranging from 0.1 to 20 p.p.m. Using ⁵¹Cr radiotracer methodology, it was demonstrated in Experiment 1 that sorption was directly related to ambient Cr concentrations after 8 days of exposure. At and above 1.0 p.p.m. Cr, negative effects on growth were evident, with seasonal variations apparently also affecting Cr uptake and toxicity. Chrome tolerance, based on the percentage of control growth achieved by exposed plants, showed S. polyrhiza to be the least tolerant to Cr, while S. punctata and L. gibba were more tolerant at concentrations above 1.0 p.p.m. In Experiment 2, duckweeds grown in nutrient-rich water with an initial concentration of 10 p.p.m. exhibited substantial growth, with bioaccumulation of Cr increasing with time.The possible use of various types of biological treatment systems for the removal of Cr from wastewater is discussed.     

Production of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in southeastern Brazil

The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, S?o Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/embryos per female × monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25?g AFDW m^?1?year^?1 and the somatic production/biomass ratio (P _s/B) from 3.55 to 3.14?year^?1 for 2004 and 2005, respectively. The P _s/B ratios were higher for males (4.02 and 3.19?year^?1 for 2004 and 2005) than for females (3.10?year^?1 for both years). The annual gonad production (P _g?=?1.07?g AFDW m^?1?year^?1) contributed about 15 and 6% to the total production (P _s?+?P _g) of females and the population, respectively. The proportion of gonad to somatic production of females (P _g/P _s) increased with individual size (ca 90% in the 7.5?mm size class), and the annual weight-specific gonad production (P _g/B ratio) was estimated to 0.24?year^?1. The high P _s/B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P _s/B ratio.     

Molecular and morphological evidence suggests the reallocation from Parastrigea brasiliana (Szidat, 1928) Dubois, 1964 to Apharyngostrigea Ciurea, 1927 (Digenea: Strigeidae), a parasite of boat-billed heron (Cochlearius cochlearius) from the Neotropical region

Parastrigea brasiliana (Szidat, 1928) Dubois, 1964, was described from (Cochlearius cochlearius) in South America. The taxonomy of this species has been unstable due that it was described as a member of Strigea Abildgaard, 1790. However, the same author one year later transferred it to Apharyngostrigea Ciurea, 1927 and since then, it has been alternatively placed in the genus Apharyngostrigea or Parastrigea Szidat, 1928 from Strigeidae. In the current research, specimens identified as P. brasiliana were collected from type host in southeastern Mexico. We sequenced three molecular markers: the internal transcribed spacers ITS1 and ITS2 including the 5.8S gene (ITS region), the D1-D3 domains of the large subunit (LSU) from nuclear DNA and cytochrome c oxidase subunit I (cox 1) from mitochondrial DNA. These sequences were aligned with other sequences available in the GenBank dataset from Strigeidae. Maximum likelihood and Bayesian analyses inferred with three molecular markers consistently showed that P. brasiliana is not closely related to other members of the genus Parastrigea and are placed in a reciprocal monophyletic clade inside Apharyngostrigea, with very low genetic divergence, varying from 0 to 0.09% for the ITS, from 0 to 0.08% for the LSU and from 0.21 to 0.43% for cox 1. Consequently, we proposed to reallocate it to A. brasiliana. The phylogenetic analyses obtained are key and very useful for re-evaluate the morphology of A. brasiliana because this species share morphological characters with the genera Parastrigea (concentration of vitelline follicles distributed in two lateral expansions on the forebody) and Apharyngostrigea (absence of pharynx). Finally, the current record of A. brasiliana expands its distribution range in four countries, namely, the USA, Mexico, Venezuela and Brazil, in the Neotropical region.     

Swimming in the sea hare Aplysia brasiliana: Cost of transport, parapodial morphometry, and swimming behavior

The energetics and behavior of the parapodial-swimming Aplysia brasiliana were investigated in order to compare net cost of transport (COT_net) between swimming and crawling, and to compare transport costs with other swimmers. Oxygen consumption (V_O2) increased with increasing animal mass for resting, crawling, and swimming animals. Slopes of the regressions of log V_O2 on log mass were 0.90, 0.91, and 0.89 for resting, crawling, and swimming, respectively. The regression for resting V_O2 on mass was significantly lower than regressions of crawling and swimming on mass, which fell into a statistically homogenous subgroup. During 4-h swimming bouts, parapodial beat frequency dropped by less than 10% of starting values after 2 h and then stabilized for the remainder of the trial, whereas velocity steadily decreased to about 70% of starting values over the 4-h period. Initial beat frequency (at the start of a swimming bout) was negatively related to body mass, varying from 1.1 beat s^− 1 for a 34 g individual to 0.7 beats s^− 1 for a 500 g individual. Final beat frequency (at the end of a swimming bout) was also negatively related to body mass, but had a significantly lower intercept than initial beat frequency. Neither initial swimming velocity nor final swimming velocity was related to mass, but final velocity was significantly lower than initial velocity. A 250 g A. brasiliana swam at 345 m h^− 1 and crawled at 7 m h^− 1. Swimming COT_net (0.1 ml O₂ kg^− 1 m^− 1) for a 250 g A. brasiliana was 50 times less than crawling COT_net (5.3 ml O₂ kg^− 1 m^− 1). While the crawling COT_net for A. brasiliana fell within the range of other marine gastropods, swimming COT_net was less than that of swimming crustaceans, and much less than another gastropod, Melibe leonina, that uses lateral bending to swim.     

Water relations and thermal sensitivity of several cockroach species (Dictyoptera: Blattidae and blaberidae)

• 1.1. Per cent total body water content (%TBW), cuticular permeability (CP), rate of water loss, critical thermal maxima (CTMax), and upper lethal limits (ULL) were determined for Pacific beetle, Diploptera punctata (Eschscholtz), Surinam, Pycnoscelus surinamensis (L.), and Turkestan, Blaita lateralis (Walker), cockroaches.
• 2.2. Initial body mass ranged from 153.16 to 464.96 mg, for D. punctata and P. surinamensis cockroaches, respectively. Mean %TBW was 57.8 for P. surinamensis and 67.7 for B. lateralis.
• 3.3. Mean cuticular permeability was not related to initial mass and ranged from 20.9 to 38.7 μg/cm²/hr/mmHg for D. punctata and P. surinamensis, respectively.
• 4.4. Cumulative mass loss and %TBW lost increased linearly with desiccation time.
• 5.5. CTMax ranged from 43.2°C for D. punctata to 44.3°C for P. surinamensis. There were significant, but small differences in CTMax among the three species.
• 6.6. ULL were 2.2 to approximately 4°C greater than CTMax. The greatest ULL was 48.1°C for B. lateralis and the lowest ULL was 45.0°C for D. punctata.

     

Genetic diversity of Pseudo-nitzschia brasiliana (Bacillariophyceae) from Malaysia

To clarify the genetic diversity of a potentially toxic pennate diatom, Pseudo-nitzschia brasiliana found in Malaysian waters, 30 strains of P. brasiliana were established into clonal culture since May 2008. The ultrastructure of these strains was examined for confirmation of species identification. The genetic marker, internal transcribed spacer (ITS) of nuclear-encoded ribosomal DNA was used to examine the genetic diversity of P. brasiliana isolated from different geographical localities. The ITS sequences of P. brasiliana were highly conserved in their secondary structures, with five helices in the first internal transcribe spacer (ITS1) and four universal helices in the second internal transcribe spacer (ITS2) with a pseudo-helix. No compensatory base change was observed among the strains examined. Genetic divergences among the Malaysian strains ranged from 0.07 to 0.54%. The present study revealed a high genetic homogeneity of Malaysian P. brasiliana strains.     

Contrasting contributions to inorganic nutrient recycling by the co-occurring jellyfishes, Catostylus mosaicus and Phyllorhiza punctata (Scyphozoa, Rhizostomeae)

The rhizostome jellyfishes, Catostylus mosaicus and Phyllorhiza punctata abound in estuaries in New South Wales, Australia. P. punctata contains symbiotic zooxanthellae but C. mosaicus contains few or no zooxanthellae. Our experiment measured the rates at which NH₃, PO₄ and NO_x were taken up or excreted by each species and in two controls: a “water only” control and a “mucus” control. Rates of uptake or excretion were measured as changes in the nutrient concentration of the water in the containers housing the animals over periods of 6 h. Experiments were repeated twice during the day and twice at night, under both ambient and enriched nutrient conditions. Under ambient nutrient conditions, the flux of NH₃ in the P. punctata treatment did not differ from the controls but under enriched conditions P. punctata excreted NH₃ during the night (49 μg kg⁻¹ WW (wet weight) h⁻¹) and took up NH₃ during the day (123 μg kg⁻¹ WW h⁻¹). In contrast, C. mosaicus excreted NH₃ at a rate of 1555 μg kg⁻¹ WW h⁻¹ during the day and 1004 μg kg⁻¹ WW h⁻¹ during the night under both enriched and ambient nutrient conditions. P. punctata neither took up nor excreted PO₄ but C. mosaicus excreted PO₄ at a faster rate during the day than night (173 μg kg⁻¹ WW h⁻¹ cf. 104 μg kg⁻¹ WW h⁻¹). Both C. mosaicus and P. punctata excreted NO_x and, although the rate of excretion for P. punctata varied between the two experiments conducted during the day, the rate of excretion was consistently greater than for C. mosaicus (52 and 80 μg kg⁻¹ WW h⁻¹ cf. 26 μg kg⁻¹ WW h⁻¹⁾. Tubs containing P. punctata had a much greater concentration of dissolved oxygen at the end of the experiments conducted during the day (152% saturation) than night (60% saturation) but tubs containing C. mosaicus had a greater dissolved oxygen concentration during the night (47% saturation) than day (39%). Overall, C. mosaicus appears to recycle more inorganic nutrients to estuaries than P. punctata. Calculations of the importance of inorganic nitrogen excreted by this species during times of peak biomass in Lake Illawarra suggest that it can meet about 8% of the phytoplankton primary production requirements of N and that its inorganic N excretion rate is about 11% of measured inorganic ammonia fluxes from sediments in that system. Since the biomass of C. mosaicus often exceeds several thousand tonnes, the contribution of inorganic nutrients by this species is substantial.     

The effect of l-methionine concentration on juvenile hormone biosynthesis by corpora allata of the cockroach Diploptera punctata

The effect of varying l-methionine (l-met) concentration on rates of juvenile hormone (JH) biosynthesis/release by corpora allata of females of the viviparous cockroach Diploptera punctata has been studied using a radiochemical assay. Both high activity glands (corpora allata from day 5 females) and low activity glands (corpora allata from day 11 females) were used to study the dose dependence of JH biosynthesis on l-met concentrations, under both de novo (spontaneous) conditions of JH biosynthesis and stimulated conditions (in the presence of the exogenous JH III precursor farnesoic acid). Maximal rates of JH biosynthesis/release were observed at l-met concentration of 20 μM (spontaneous) and 40 μM (stimulated). Below these concentrations, rates of JH biosynthesis declined linearly with decreasing l-met concentration. Optimal concentration of l-met appeared to be similar for both high and low activity corpora allata, under spontaneous and stimulated conditions of biosynthesis. Above 40 μM l-met, no increase in rates of JH biosynthesis was observed. It appears that the corpora allata of D. punctata are efficient scavengers of l-met and are able to utilize even low concentrations of the substrate for JH biosynthesis. The corpora allata of D. punctata may prove useful for the biosynthesis of authentic JH III, radiolabelled in the methyl position using as methyl donor, l[methyl-³H]met of high specific activity.     

Population size and structure of giant clams at Rose Atoll, an important refuge in the Samoan Archipelago

Rose Atoll is an important refuge for giant clams (Tridacna maxima) that have been heavily exploited elsewhere in Samoa. During an extensive survey of six islands in the archipelago (50.5?ha surveyed in 420 transects), 97% of a total of 2853 clams were recorded at the atoll (42% of area surveyed). Clam densities were highest in the atoll lagoon, especially around the bases of the pinnacles (mean density=8870?ha^-1). Estimated population size for the small atoll (615?ha) was approximately 27800 clams. Twenty four percent of the population consisted of mature clams (?12?cm), 70% of which occupied the pinnacles and shallow lagoon habitat. Estimated mortality was low (Z=0.3) and primarily due to natural mortality (M=0.3). Maximum recorded size (L _max ) and asymptotic mean size (L _∞) were 25.0?cm and 27.8?cm respectively.     

Terminal stages in juvenile hormone biosynthesis in corpora allata of Diploptera punctata: Developmental changes in enzyme activity and regulation by allatostatins

The O-methyltransferase, which is responsible for the methylation of farnesoic acid in the corpora allata of Diploptera punctata, is a cytosolic enzyme. The activity of O-methyltransferase closely parallels JH biosynthesis in last instars and adult females. Because allatostatin 4 (AST 4) from D. punctata and callatostatin 5 (CAST 5) from Calliphora vomitoria can inhibit juvenile hormone biosynthesis, their effects on the activity of O-methyltransferase and epoxidase, the enzymes involved in the final two steps of juvenile hormone biosynthesis, were investigated in vitro. AST 4 can inhibit methyltransferase activity whereas CAST 5 stimulates it. AST 4 inhibits epoxidase activity slightly whereas CAST 5 inhibits it significantly (36%). Treatment of corpora allata with farnesoic acid (40 μM) can reverse the inhibitory effect of AST 4 and CAST 5 on JH release by corpora allata. Thus, allatostatins appear to exert their inhibitory effect on JH biosynthesis at least partially through inhibition of the activity of terminal enzymes. Two biosynthetic pathways for the conversion of farnesoic acid to JH may exist in corpora allata of D. punctata: the predominant pathway is farnesoic acid to methyl farnesoate, then to JH whereas the other, representing about 5–10% of total JH production, is farnesoic acid to JH III acid, then to JH.     

Engineering of formate dehydrogenase: synergistic effect of mutations affecting cofactor specificity and chemical stability

Formate dehydrogenases (FDHs) are frequently used for the regeneration of cofactors in biotransformations employing NAD(P)H-dependent oxidoreductases. Major drawbacks of most native FDHs are their strong preference for NAD⁺ and their low operational stability in the presence of reactive organic compounds such as α-haloketones. In this study, the FDH from Mycobacterium vaccae N10 (MycFDH) was engineered in order to obtain an enzyme that is not only capable of regenerating NADPH but also stable toward the α-haloketone ethyl 4-chloroacetoacetate (ECAA). To change the cofactor specificity, amino acids in the conserved NAD⁺ binding motif were mutated. Among these mutants, MycFDH A198G/D221Q had the highest catalytic efficiency (k _cat/K _m) with NADP⁺. The additional replacement of two cysteines (C145S/C255V) not only conferred a high resistance to ECAA but also enhanced the catalytic efficiency 6-fold. The resulting quadruple mutant MycFDH C145S/A198G/D221Q/C255V had a specific activity of 4.00?±?0.13 U?mg^?1 and a K _{m, NADP} ⁺ of 0.147?±?0.020 mM at 30 °C, pH 7. The A198G replacement had a major impact on the kinetic constants of the enzyme. The corresponding triple mutant, MycFDH C145S/D221Q/C255V, showed the highest specific activity reported to date for a NADP⁺-accepting FDH (v _max, 10.25?±?1.63 U?mg^?1). However, the half-saturation constant for NADP⁺ (K _{m, NADP} ⁺ , 0.92?±?0.10 mM) was about one order of magnitude higher than the one of the quadruple mutant. Depending on the reaction setup, both novel MycFDH variants could be useful for the production of the chiral synthon ethyl (S)-4-chloro-3-hydroxybutyrate [(S)-ECHB] by asymmetric reduction of ECAA with NADPH-dependent ketoreductases.     

Factors affecting biohydrogen production by unicellular halotolerant cyanobacterium Aphanothece halophytica

The effects of several physiological parameters on H₂ production rate in the unicellular halotolerant cyanobacterium Aphanothece halophytica were investigated. Under nitrogen deprivation, the growth of cells was inhibited, but H₂ production rate was enhanced approximately fourfold. Interestingly, cells grown under sulfur deprivation exhibited a decrease in cell growth, H₂ production rate, and bidirectional hydrogenase activity. Glucose was the preferred sugar source for H₂ production by A. halophytica, but H₂ production decreased at high glucose concentrations. H₂ production rate was optimum when cells were grown in the presence of 0.75 M?NaCl, or 0.4 μM?Fe³⁺, or 1 μM?Ni²⁺. The optimum light intensity and temperature for H₂ production were 30 μmol photons m^?2?s^?1 and 35 °C, respectively. A two-stage culture of A. halophytica was performed in order to overcome the reduction of cell growth in N-free medium. In the first stage, cells were grown in normal medium to accumulate biomass, and in the second stage, H₂ production by the obtained biomass was induced by growing cells in N-free medium supplemented with various chemicals for 24 h. A. halophytica grown in N-free medium containing various MgSO₄ concentrations had a high H₂ production rate between 11.432 and 12.767 μmol H₂ mg?chlorophyll a (chl a)^?1?h^?1, a 30-fold increase compared to cells grown in normal medium. The highest rate of 13.804 μmol H₂ mg?chl a ^?1?h^?1 was obtained when the N-free growth medium contained 0.4 μM Fe³⁺. These results suggested the possibility of using A. halophytica and some other halotolerant cyanobacteria thriving under extreme environmental conditions in the sea as potential sources for H₂ production in the future.     

Molecular identification of a novel inulinolytic fungus isolated from and grown on tubers of Helianthus tuberosus and statistical screening of medium components

Of 24 fungi belonging to more than five genera isolated from tubers of rotten Helianthus tuberosus, 11-inulinolytic active isolates were able to develop halo zones around their fungal colonies, indicating inulinase activity. Alternaria, Aspergillus, Fusarium, Pencillium and Trichoderma were the most common inulinolytic genera, representing more than 90?% of the total positive inulinolytic fungi. Aspergillus tamarii and Pencillium citrinum quantitatively recorded better growth (5.5 and 4.7?mg?ml^?1) and inulinase production (21.53 and 20.15?U?ml^?1) in submerged culture. The enzyme preparation showed also invertase activity. Aspergillus tamarii, as the most potent producer of inulinase, was identified using the Inter Transcribed Spacer marker. The sequence comparisons showed that our molecularly identified strain (GU295949) is related more closely to A. tamarii strains of the gene bank. Statistical screening using the fractional factorial Plackett-Burman design with 12 run was applied for screening ten variables, the low levels of pH (4.8), inoculum size (10³ spore?g^?1), NH₄NO₃ (1.0?mg?g^?1) and MgSO₄ (0.12?mg?g^?1), were the most significant variables on A. tamarii inulinase production. The high inulinase/invertase ratio (1.841?C4.293) classified the enzyme preparation as inulinases, which can be used efficiently in production of fructose syrup from tubers of H. tuberosus.     

Effect of mixed carbon substrate on exopolysaccharide production of cyanobacterium Nostoc flagelliforme in mixotrophic cultures

The effects of organic carbon sources on cell growth and exopolysaccharide (EPS) production of dissociated Nostoc flagelliforme cells under mixotrophic batch culture were investigated. After 7?days of cultivation, glycerol, acetate, sucrose, and glucose increased the final cell density and final EPS concentrations, and mixotrophic growth achieved higher biomass concentrations. The increase in cell growth was particularly high when glucose was added as the sole carbon source. On the other hand, EPS production per dry cell weight was significantly enhanced by adding acetate. For more effective EPS production, the effects of the mixture of glucose and acetate were investigated. Increasing the ratio of glucose to acetate resulted in higher growth rate with BG-11 medium and higher EPS productivity with BG-11₀ medium (without NaNO₃). When the medium was supplemented with a mixture of glucose (4.0?g?L^?1) and acetate (2.0?g?L^?1), 1.79?g?L^?1 biomass with BG-11 medium and 879.6?mg?L^?1 of EPS production with BG-11₀ medium were achieved. Adopting this optimal ratio of glucose to acetate established in flask culture, the culture was also conducted in a 20-L photobioreactor with BG-11 medium for 7?days. A maximum biomass of 2.32?g?L^?1 was achieved, and the EPS production was 634.6?mg?L^?1.     

Reproductive cycle and parasitism in the clam Anomalocardia brasiliana (Bivalvia: Veneridae)

The reproductive cycle and parasitism in the clam Anomalocardia brasiliana were studied in two different areas, an intermediate beach (Cidade) and a tidal flat (Araçá), in Southeast Brazil. Four gametogenic stages were described for males and females in both areas. Mature and spawning individuals were present throughout the period of study at Cidade and Araçá; however, major temporal differences were recorded between sites. Whereas only a few individuals in the resting stage were recorded at Cidade throughout the study period, resting stage individuals were frequent at Araçá. Moreover, a shorter period of gametogenesis was observed at Araçá than at Cidade. Oocyte number was the most effective parameter to differentiate gametogenic stages. An unidentified digenetic trematode was the only parasite infecting A. brasiliana at the study sites, and caused castration of all hosts. Parasite prevalence (proportion of infected hosts) was similar and low (ca 7.5%) at Cidade and Araçá and therefore is not expected to compromise the reproductive output of these populations. Comparison with data from previous studies suggests a latitudinal pattern for the reproductive biology of A. brasiliana, with resting stages occurring only at two high-latitude sites; however, no evidence was found for a latitudinal pattern of trematode prevalence in this species.     

Variability in shoot cultures regenerated from hairy roots of Gentiana punctata

Differences among three clones of Gentiana punctata L. hairy root shoot regenerants were investigated in relation to their growth patterns, production of secondary metabolites and 2D protein profiles. Prominent differences in growth parameters were stable thus qualifying regenerant clones as true somaclones. Marked differences in protein spots were registered among the regenerant clones but not in comparison with the non-transformed control. Southern blot hybridization of regenerants showed the absence of rolA, B and C genes, initially present in the main hairy root lines. Orf13 and rolD were present and orf8 was missing in all three regenerant clones whereas orf3 was missing only in clone 2. Although lacking the three major rol genes, plants of regenerant clones retained characteristics of the hairy root phenotype.     

Variability in the numbers of post-settlement King George whiting (Sillaginidae: Sillaginodes punctata, Cuvier) in relation to predation, habitat complexity and artificial cage structure

The importance of predation by fish in altering abundances of juvenile King George whiting (Sillaginodes punctata) was examined at multiple locations in Port Phillip Bay, Australia, by manipulating the numbers of piscivorous fish in unvegetated sand and seagrass habitats using cages. Additional information regarding the local abundances of, and habitat use by, the most common piscivorous fish, Western Australian salmon (Arripidae: Arripis truttacea, Cuvier), was gathered using netting surveys and underwater video. Regardless of habitat, abundances of S. punctata were similar in partial cages and uncaged areas. In unvegetated sand, S. punctata were more abundant inside cages than partial cages or uncaged areas. In seagrass, there was no difference in the numbers of S. punctata between caging treatments. Patterns in abundances of S. punctata between cage treatments in each habitat were consistent between sites, but the relative difference in the abundances of S. punctata between habitats was site specific. Abundances of A. truttacea varied significantly between sites, and they consumed a variety of epibenthic fishes including atherinids, clupeids, gobiids, syngnathids and pleuronectids. At one site in Port Phillip Bay (Blairgowrie), A. truttacea occurred more commonly in patches of unvegetated sand than seagrass. Over unvegetated sand, abundances of A. truttacea varied little between partial cages and uncaged areas. The numbers of S. punctata varied between caging treatments and habitats in a manner that was consistent with a model whereby seagrass interferes with foraging by predatory fish and provides juvenile fish with a refuge from predation. The almost total absence of A. truttacea in seagrass habitats and the lack of S. punctata in their diets implies, however, that patterns in S. punctata in seagrass/unvegetated sand mosaics are driven by processes other than direct predation.     

Recovery of sandy beach and maritime forest vegetation on Phuket Island (Thailand) after the major Indian Ocean tsunami of 2004

Question: How rapidly has the sandy beach and maritime forest vegetation on Phuket recovered and regenerated after the impact of the major Indian Ocean tsunami of 2004? What are the characteristics of sandy beach species for regenerating their populations and the invasion patterns of originally non-sandy beach species or other newcomers after the tsunami? Location: Phuket Island, southern Thailand. Methods: Species composition of beaches was studied on the same research plots 6 months before and 9 months after the tsunami. The changes in individual species cover before and after the tsunami were determined by χ² tests. Change in community composition was analysed by detrended correspondence analysis. The relationship between species and environmental factors was analysed by canonical correspondence analysis. Results: The sites disturbed by the tsunami were often invaded by annuals, especially grasses and asteraceous plants, rather than by perennials. In contrast, species with clonal growth by stolons decreased significantly. Factors determining the species habitat differences were soil hardness (penetration resistance of sandy soil), per cent silt content, soil water content and beach management. Habitat differences among originally non-sandy beach herbaceous species that expanded their population or moved to the coast after the disaster were defined by sand accretion or erosion caused by the tsunami. Many sandy beach herbaceous communities changed into Dactyloctenium aegyptium communities because of the tsunami were originally constituted by non-sandy beach D. aegyptium with Cenchrus echinatus. Although the forest floors of most maritime forests were invaded by originally non-sandy beach Tridax procumbens, Eleusine indica or D. aegyptium because of the tsunami, this did not result in a change in the vegetation unit, because species' loss was restricted to the understorey. In time, these forests will recover their previous community composition. Conclusions: Our results suggest that originally non-sandy beach native species invaded the disturbed beaches rapidly after the tsunami but their habitats differ. Sites where sand accumulated on a beach because of the tsunami were invaded by D. aegyptium and E. indica, whereas soil erosion permitted invasion by Digitania adscendens. Tridax procumbens establishes rapidly on wet sites with hard soil, high per cent silt content and low beach management pressure. Sandy beach species with subterranean long rhizomes are strongly tolerant of such disasters. We concluded that the species composition of the beaches disturbed by a temporary large disaster is determined by dormancy and growth forms, with radicoid form being influential.