Distribution,density, and habitat use among native and introduced populations of the Australasian burrowing isopod <Emphasis Type="Italic">Sphaeroma quoianum</Emphasis>

The Australasian burrowing isopod (Sphaeroma quoianum) has been introduced to numerous embayments along the Pacific coast of North America. In some bays, populations of S. quoianum can exceed tens of thousands of individuals m⁻³ and bioturbation by the isopods can exacerbate shoreline erosion. Within their native range, however, studies recognize S. quoianum primarily as a woodborer. We measured the distribution, prevalence, habitat use, density, and associated fauna of S. quoianum in two bays within the native range [Tamar estuary (Tamar), Tasmania and Port Phillip Bay (PPB), VIC, Australia] and in one bay where the isopods had been introduced (Coos Bay, OR, USA). Distribution, prevalence, and habitat use were determined from shoreline surveys. Densities and the associated fauna of S. quoianum were measured in three intertidal substrata (marsh bank, wood, and friable rock). In all embayments, S. quoianum occurred primarily between 5 and 30 salinity and 55−68% of sites harbored isopods. Habitat use varied between embayments. Distributional patterns suggest salinity is the primary factor that limits the establishment and spread of S. quoianum. Isopod densities in all substrata were greater in Coos Bay than in the Tamar or PPB, although only densities within marsh banks varied significantly. Similarities in the amount of habitat and food, and the burrow dwelling lifestyle of S. quoianum suggest habitat availability/quality, food levels, predation, and competition are not responsible for the large differences in density. Lack of parasites or disease in populations of S. quoianum introduced to Coos Bay could be responsible for the prolific densities observed.     

Isolation of a Novel <Emphasis Type="Italic">N</Emphasis>-acetyl-<Emphasis Type="SmallCaps">d</Emphasis>-lactosamine Specific Lectin from <Emphasis Type="Italic">Alocasia cucullata</Emphasis> (Schott.)

An N-acetyl-d-lactosamine (LacNAc) specific lectin from tubers of Alocasia cucullata was purified by affinity chromatography on asialofetuin-linked amino activated silica. The pure lectin showed a single band in SDS-PAGE at pH 8.8 and was a homotetramer with a subunit molecular mass of 13.5 kDa and native molecular mass of 53 kDa. It was heat stable up to 55 °C for 15 min and showed optimum hemagglutination activity from pH 2 to 11. The lectin was affected by denaturing agents such as urea (2 m), thiourea (2 m) and guanidine–HCl (0.5 m) and did not require Ca²⁺ and Mn²⁺ for its activity. It was a potent mitogen at 10 μg/ml towards human peripheral blood mononuclear cells with 50% growth inhibitory potential towards SiHa (human cervix ) cancer cell line at 100 μg/ml.     

Fumigant toxicity of cassia bark and cassia and cinnamon oil compounds to <Emphasis Type="Italic">Dermatophagoides </Emphasis><Emphasis Type="Italic">farinae </Emphasis>and <Emphasis Type="Italic">Dermatophagoides pteronyssinus</Emphasis> (Acari: Pyroglyphidae)

The toxicity to adults of the American house dust mite, Dermatophagoides farinae, and the European house dust mite, Dermatophagoides pteronyssinus, of cassia bark and cassia and cinnamon oil compounds was examined using residual contact and vapour-phase toxicity bioassays. Results were compared with those of the currently used acaricides: benzyl benzoate and dibutyl phthalate. The acaricidal principles of cassia bark were identified as (E)-cinnamaldehyde and salicylaldehyde. In fabric-circle residual contact bioassays with adult D. farinae, salicylaldehyde (17.3 mg/m²) and (E)-cinnamaldehyde (25.8 mg/m²) were 2.5 and 1.7 times more toxic than benzyl benzoate (43.7 mg/m²), respectively, based on 24-h LD₅₀ values. The acaricidal activity was more pronounced in benzaldehyde, menthol, α-terpineol, and thymol (70.8–234.3 mg/m²) than in dibutyl phthalate (281.0 mg/m²). Against adult D. pteronyssinus, salicylaldehyde (17.3 mg/m²) and (E)-cinnamaldehyde (19.3 mg/m²) were 2.4- and 2.2-fold more active than benzyl benzoate (41.9 mg/m²). The toxicity of benzaldehyde, menthol, α-terpineol, and thymol (75.3–179.2 mg/m²) was higher than that of dibutyl phthalate (285.1 mg/m²). In vapour-phase toxicity tests with adult D. farinae, the test compounds described were much more effective in closed—but not in open—containers, indicating that the effect of these compounds was largely a result of action in the vapour phase.     

Growth,biomass allocation,morphology, and photosynthesis of invasive <Emphasis Type="Italic">Eupatorium</Emphasis><Emphasis Type="Italic">adenophorum</Emphasis> and its native congeners grown at four irradiances

Eupatorium adenophorum is one of the more noxious invasive plants worldwide. However, the mechanisms underlying its invasiveness are still not well elucidated. In this study, we compared the invader with its two native congeners (E. heterophyllum and E. japonicum) at four irradiances in terms of growth, biomass allocation, morphology, and photosynthesis. The higher light-saturated photosynthetic rate (P _max) and total leaf area of the invader may contribute to its higher relative growth rate (RGR) and total biomass compared with its native congeners. Total biomass and RGR increased significantly with the increase of P _max and total leaf area. The higher support organ mass fraction and the lower root mass fraction of the invader may also contribute to its higher RGR and biomass through increasing carbon assimilation and reducing respiratory carbon loss, respectively. The higher growth rate of the invader increased its total leaf area, ramet number, and crown area. These traits may help the invader to form dense monoculture, outshading native plant species. However, consistently higher leaf area ratio, specific leaf area, and leaf mass fraction were not found across irradiances for the invader compared with its native congeners. Higher plasticity in response to irradiance was also not found for the invader. The invader retained advantages over the natives across irradiances, while its performance decreased with lower irradiance. The results indicate that the invader may be one of the few super invaders. Reducing irradiance may inhibit its invasions.     

Four novel <Emphasis Type="Italic">Candida</Emphasis> species in the <Emphasis Type="Italic">Candida albicans</Emphasis>/<Emphasis Type="Italic">Lodderomyces elongisporus</Emphasis> clade isolated from the gut of flower beetles

Flower-visiting beetles belonging to three species of Cetoniidae were collected on three mountains near Beijing, China, and yeasts were isolated from the gut of the insects collected. Based on the 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequence analysis and phenotypic characterization, four novel anamorphic yeast species located in the Candida albicans/Lodderomyces elongisporus clade were identified from 18 of the strains isolated. The new species and type strains are designated as Candida blackwellae AS 2.3639^T (=CBS 10843^T), Candida jiufengensis AS 2.3688^T (=CBS 10846^T), Candida oxycetoniae AS 2.3656^T (=CBS 10844^T), and Candida pseudojiufengensis AS 2.3693^T (=CBS 10847^T). C. blackwellae sp. nov. was basal to the branch formed by C. albicans and C. dubliniensis with moderately strong bootstrap support. The closest relative of C. oxycetoniae was L. elongisporus. C. jiufengensis sp. nov. and C. pseudojiufengensis sp. nov. were closely related with each other and formed a branch in a subclade represented by C. parapsilosis and L. elongisporus.     

Purification and Properties of an <Emphasis Type="Italic">N</Emphasis>-acetylglucosaminidase from <Emphasis Type="Italic">Streptomyces cerradoensis</Emphasis>

An N-acetylglucosaminidase produced by Streptomyces cerradoensis was partially purified giving, by SDS-PAGE analysis, two main protein bands with Mr of 58.9 and 56.4 kDa. The K_m and V_max values for the enzyme using p-nitrophenyl-β-N-acetylglucosaminide as substrate were of 0.13 mM and 1.95 U mg⁻¹ protein, respectively. The enzyme was optimally activity at pH 5.5 and at 50 °C when assayed over 10 min. Enzyme activity was strongly inhibited by Cu²⁺ and Hg²⁺ at 10 mM, and was specific to substrates containing acetamide groups such as p-nitrophenyl-β-N-acetylglucosaminide and p-nitrophenyl-β-D-N,N′-diacetylchitobiose.     

Indirect food web effects of <Emphasis Type="Italic">Bythotrephes</Emphasis> invasion: responses by the rotifer <Emphasis Type="Italic">Conochilus</Emphasis> in Harp Lake,Canada

As a recent invader of North American lakes, Bythotrephes longimanus has induced large changes in crustacean zooplankton communities through direct predation effects. Here we demonstrate that Bythotrephes can also have indirect food web effects, specifically on rotifer fauna. In historical time series data, the densities of the colonial rotifer Conochilus unicornis significantly increased after Bythotrephes invasion in Harp Lake, Ontario. No such changes were observed in a non-invaded reference lake, the nearby Red Chalk Lake. Evidence for two mechanisms explaining the Conochilus increase was examined based on changes to the crustacean zooplankton community over time. Rapid and severe declines in several herbivorous species of cladoceran zooplankton after Bythotrephes detection indicated a decrease in exploitative competition pressure on Conochilus. Secondly, a later and significant decline to virtual extinction of native invertebrate predators (Mesocyclops and Leptodora) could account for the observed Conochilus increase which also began 1–2 years after invasion by Bythotrephes. Ultimately, it appears that both reduced competition followed by a loss of native invertebrate predators were necessary to lead to the large Conochilus densities observed following invader establishment. From this analysis of long-term community data, it appears that Bythotrephes has important indirect, as well as direct, food web effects in newly invaded North American lakes with implications for trophic relationships.     

Lifestyle of Korean mudskipper <Emphasis Type="Italic">Periophthalmus magnuspinnatus</Emphasis> with reference to a congeneric species <Emphasis Type="Italic">Periophthalmus modestus</Emphasis>

To investigate the life history and ecology of the mudskipper Periophthalmus magnuspinnatus, observations and collection were made on coastal mudflats in southern Korea. Periophthalmus magnuspinnatus was active from May to September on the mudflats, exclusively occupying rough and elevated or sloped mudflats of the seashore or the stream mouth, usually vegetated with halophilous grasses. The congeneric species, P. modestus, mainly occurred on extensive low-elevation and level mudflats with no visible vegetation. An apparent alternation of habitat use by P. modestus took place on mudflats at the stream mouth in mid-October, when P. magnuspinnatus began wintering in its burrow and P. modestus came onto the vacated mudflats to construct burrows for wintering. The active season for P. magnuspinnatus at 17°C or higher air temperature was a little shorter than that of P. modestus. Periophthalmus magnuspinnatus constructed a burrow for the entire season in the highest area of the intertidal mudflat, where they hid themselves during high tide or when frightened, whereas P. modestus were likely to use any burrow constructed by other animals or sunken places to hide. The main stomach contents of P. magnuspinnatus were crabs and gammarids. During the reproductive season from May to July, P. magnuspinnatus performed mating behaviors and constructed a spawning burrow similar to the ones known for P. modestus, except their body color turned dark and quivering body movements were observed in the mature male instead of a pink or orange body color and wiggling body movements as in P. modestus. Eggs, measuring 1.56–1.69 mm in major axis and 0.94–1.0 mm in minor axis, were laid on the ceiling and the side wall of the “J”-shaped spawning room generally known for Periophthalmus species. Young of both species started to occur on the mudflat in June.     

<Emphasis Type="Italic">Nimbya alternantherae</Emphasis> a potential biocontrol agent for alligatorweed, <Emphasis Type="Italic">Alternanthera philoxeroides</Emphasis>

Alligatorweed, (Alternanthera philoxeroides (Mart.) Griseb.), an aquatic and wetland plant native to South America, is an aggressive weed in many parts of the world. Its ability to compete with other native plants and to impede waterways has made it a serious threat to aquatic ecosystems. Although biological control with insects has been fairly successful in aquatic habitats, there is a need for additional agents to manage the weed in upland sites. Accordingly, in a survey in Brazil in 1997 a fungus, Nimbya (=Alternaria) alternantherae (Holcomb and Antonopoulus) Simmons and Alcorn, was discovered and confirmed to be highly damaging to alligatorweed. Studies were conducted to determine the potential of this fungus for controlling this weed. Several isolates from Brazil, USA, and Puerto Rico were compared and no differences in virulence were observed, although a lower dew requirement was demonstrated for the Brazilian isolates. Conidia were more effective than mycelial suspension, and inoculum concentrations of 1×10⁵ and 1×10⁶ conidia per ml provided significant levels of control of the weed in greenhouse and field experiments, respectively. In a host-range study, N. alternantherae infected 6 plant species from a total of 42 species belonging to 23 families. N. alternantherae has the potential to be an effective mycoherbicide for alligatorweed.     

Isolate-specific effects of ultraviolet radiation on photosynthesis,growth and mycosporine-like amino acids in the microbial mat-forming cyanobacterium <Emphasis Type="Italic">Microcoleus </Emphasis><Emphasis Type="Italic">chthonoplastes</Emphasis>

Microcoleus chthonoplastes constitutes one of the dominant microorganisms in intertidal microbial mat communities. In the laboratory, the effects of repeated daily exposure to ultraviolet radiation (16:8 light:dark cycle) was investigated in unicyanobacterial cultures isolated from three different localities (Baltic Sea = WW6; North Sea = STO and Brittany = BRE). Photosynthesis and growth were measured in time series (12–15 days) while UV-absorbing mycosporine-like amino acids (MAAs) and cellular integrity were determined after 12 and 3 days exposure to three radiation treatments [PAR (22 μmol photon m⁻² s⁻¹) = P; PAR + UV-A (8 W m⁻²) = PA; PAR + UV-A + UV-B (0.4 W m⁻²) = PAB]. Isolate-specific responses to UVR were observed. The proximate response to radiation stress after 1-day treatment showed that isolate WW6 was the most sensitive to UVR. However, repeated exposure to radiation stress indicated that photosynthetic efficiency (F _v/F _m) of WW6 acclimated to UVR. Conversely, although photosynthesis in STO exhibited lower reduction in F _v/F _m during the first day, the values declined over time. The BRE isolate was the most tolerant to radiation stress with the lowest reduction in F _v/F _m sustained over time. While photosynthetic efficiencies of different isolates were able to acclimate to UVR, growth did not. The discrepancy seems to be due to the higher cell density used for photosynthesis compared to the growth measurement. Apparently, the cell density used for photosynthesis was not high enough to offer self-shading protection because cellular damage was also observed in those filaments under UVR. Most likely, the UVR acclimation of photosynthesis reflects predominantly the performance of the surviving cells within the filaments. Different strategies were observed in MAAs synthesis. Total MAAs content in WW6 was not significantly different between all the radiation treatments. In contrast, the additional fluence of UV-A and UV-B significantly increased MAAs synthesis and accumulation in STO while only UV-B fluence significantly increased MAAs content in BRE. Regardless of the dynamic photosynthetic recovery process and potential UV-protective functions of MAAs, cellular investigation showed that UV-B significantly contributed to an increased cell mortality in single filaments. In their natural mat habitat, M. chthonoplastes benefits from closely associated cyanobacteria which are highly UVR-tolerant due to the production of the extracellular UV-sunscreen scytonemin.     

Potential for endophyte symbiosis to increase resistance of the native grass <Emphasis Type="Italic">Poa alsodes</Emphasis> to invasion by the non-native grass <Emphasis Type="Italic">Microstegium vimineum</Emphasis>

Microbial symbionts can improve the competitive ability and stress tolerance of plant hosts and thus may enhance native plant resistance against invaders. We investigated whether symbiosis between a native grass, Poa alsodes, and a fungal endophyte (Neotyphodium sp.) improved the grass’s ability to compete against Microstegium vimineum (Japanese stiltgrass), a common invader in the eastern USA. We challenged naturally endophyte-symbiotic and experimentally endophyte-free P. alsodes plants with the invader. In the first experiment, we manipulated symbiosis and water availability to test for context-dependency in symbiont benefits. In the second experiment, we manipulated symbiosis and M. vimineum diversity (the number of invader populations), since greater intraspecific diversity is expected to improve invasion success and might alter the efficacy of symbiosis in invasion resistance. In both experiments, presence of the endophyte reduced the per plant biomass of M. vimineum and increased P. alsodes biomass. We found no evidence that benefits of the symbiont depended on water availability, and population-level diversity had a minor influence on M. vimineum: inflorescence number showed a parabolic relationship with increasing numbers of M. vimineum populations. Overall, symbiosis in the native grass had stronger effects on invader growth than either water availability or invader genetic diversity. Our results suggest that endophyte symbioses in native plants can increase host performance against an invader, although this conclusion needs confirmation in more complex field settings where other important factors, such as herbivores and fluctuating abiotic conditions, come into play.     

Invasive alga <Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> makes a strong impact on the Mediterranean sponge <Emphasis Type="Italic">Sarcotragus spinosulus</Emphasis>

Here we present the first observation of the impact of the invasive Caulerpa racemosa var. cylindracea on native photophilic sponge species in the Adriatic Sea, with special focus on Sarcotragus spinosulus. Caulerpa racemosa var. cylindracea is able to completely overgrow the sponge, developing an exceptionally thick canopy with a maximum measured density of 1,887 m of stolons m⁻² and 40,561 fronds m⁻². Necrosis of the sponge surface was significantly correlated with the algal dry biomass, frond number and stolon length. Dense algal canopy, penetration of the algal stolon and rhizoids into the sponge oscula and covering of the ostiae probably diminishes the seawater circulation through the sponge and consequently results in its smothering and even death. We suggest that chemotropism is the reason why C. racemosa penetrates the sponge oscula and establishes such dense canopy on the sponge.     

New species of <Emphasis Type="Italic">Eugenia</Emphasis> sect. <Emphasis Type="Italic">Racemosae</Emphasis> (Myrtaceae) from Brazilian Amazon Rainforest

Summary  The new species Eugenia pallidopunctata, E. caducibracteata, E. tenuiflora and E. breviracemosa from the Brazilian Amazon, all belonging to Eugenia sect. Racemosae (Myrtaceae), are described, illustrated and compared with their putative close relatives. Data on the geographic distribution and habitat are given for the new taxa, as well as illustrations.     

Heterologous expression of the <Emphasis Type="Italic">msp2 gene</Emphasis> from <Emphasis Type="Italic">Marasmius scorodonius</Emphasis>

For the heterologous expression of the msp2 gene from the edible mushroom Marasmius scorodonius in Escherichia coli the cDNA encoding the extracellular Msp2 peroxidase was cloned into the pBAD III expression plasmid. Expression of the protein with or without signal peptide was investigated in E. coli strains TOP10 and LMG194. Different PCR products were amplified for expression of the native target protein or a protein with a signal peptide. Omitting the native stop codon and adding six His-residues resulted in a fusion protein amenable to immune detection and purification by immobilised metal affinity chromatography. In E. coli the recombinant protein was produced in high yield as insoluble inclusion bodies. The influence of different parameters on MsP2 refolding was investigated. Active enzyme was obtained by glutathione-mediated oxidation in a medium containing urea, Ca²⁺, and hemin.     

Male rescue maintains low frequency parthenogenesis-inducing <Emphasis Type="Italic">Wolbachia</Emphasis> infection in <Emphasis Type="Italic">Trichogramma</Emphasis> populations

Parthenogenesis-inducing (PI) Wolbachia bacteria are reproductive parasites that cause infected (W ⁺) female haplodiploid parasitoids to produce daughters without fertilization by males. Theoretically, PI Wolbachia infection should spread to fixation within Trichogramma populations as males are no longer required to produce female offspring. Infections in some naturally occurring Trichogramma populations are, however, maintained at frequencies ranging from 4 to 26%. Here we describe discrete equation models to examine if the PI Wolbachia infection in Trichogramma populations can be maintained at relatively low frequencies by mating regularity. Model outcomes suggest the probability of W ⁺ females mating could stabilize Wolbachia infection frequency at low levels in Trichogramma populations. The primary mechanism maintaining low-level PI Wolbachia infection in Trichogramma populations is reducing the survivorship from egg to adult in infected relative to uninfected females. The model successfully demonstrates that the relatively low PI Wolbachia infection frequency in host populations can be maintained by fertilization, or male rescue, of infected eggs, which avoids potentially hazardous gamete duplication that occurs during Wolbachia-induced parthenogenesis.     

Invasion of <Emphasis Type="Italic">Spartina alterniflora</Emphasis> Enhanced Ecosystem Carbon and Nitrogen Stocks in the Yangtze Estuary,China

Whether plant invasion increases ecosystem carbon (C) stocks is controversial largely due to the lack of knowledge about differences in ecophysiological properties between invasive and native species. We conducted a field experiment in which we measured ecophysiological properties to explore the response of the ecosystem C stocks to the invasion of Spartina alterniflora (Spartina) in wetlands dominated by native Scirpus mariqueter (Scirpus) and Phragmites australis (Phragmites) in the Yangtze Estuary, China. We measured growing season length, leaf area index (LAI), net photosynthetic rate (Pn), root biomass, net primary production (NPP), litter quality and litter decomposition, plant and soil C and nitrogen (N) stocks in ecosystems dominated by the three species. Our results showed that Spartina had a longer growing season, higher LAI, higher Pn, and greater root biomass than Scirpus and Phragmites. Net primary production (NPP) was 2.16 kg C m⁻² y⁻¹ in Spartina ecosystems, which was, on average, 1.44 and 0.47 kg C m⁻² y⁻¹ greater than that in Scirpus and Phragmites ecosystems, respectively. The litter decomposition rate, particularly the belowground decomposition rate, was lower for Spartina than Scirpus and Phragmites due to the lower litter quality of Spartina. The ecosystem C stock (20.94 kg m⁻²) for Spartina was greater than that for Scirpus (17.07 kg m⁻²), Phragmites (19.51 kg m⁻²) and the mudflats (15.12 kg m⁻²). Additionally, Spartina ecosystems had a significantly greater N stock (698.8 g m⁻²) than Scirpus (597.1 g m⁻²), Phragmites ecosystems (578.2 g m⁻²) and the mudflats (375.1 g m⁻²). Our results suggest that Spartina invasion altered ecophysiological processes, resulted in changes in NPP and litter decomposition, and ultimately led to enhanced ecosystem C and N stocks in the invaded ecosystems in comparison to the ecosystems with native species.     

Purification and properties of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis><Emphasis Type="Italic">S</Emphasis>-adenosylmethionine synthetase expressed in recombinant <Emphasis Type="Italic">Pichia pastoris</Emphasis>

An intracellular S-adenosylmethionine synthetase (SAM-s) was purified from the fermentation broth of Pichia pastoris GS115 by a sequence chromatography column. It was purified to apparent homogeneity by (NH₄)₂SO₄ fractionation (30–60%), anion exchange, hydrophobic interaction, anion exchange and gel filtration chromatography. HPLC showed the purity of purified SAM-s was 91.2%. The enzyme was purified up to 49.5-fold with a final yield of 20.3%. The molecular weight of the homogeneous enzyme was 43.6 KDa, as determined by electro-spray ionization mass spectrometry (ESI-MS). Its isoelectric point was approximately 4.7, indicating an acidic character. The optimum pH and temperature for the enzyme reaction were 8.5 and 35 °C, respectively. The enzyme was stable at pH 7.0–9.0 and was easy to inactivate in acid solution (pH ≤ 5.0). The temperature stability was up to 45 °C. Metal ions, such as, Mn²⁺ and K⁺ at the concentration of 5 mM had a slight activation effect on the enzyme activity and the Mg²⁺ activated the enzyme significantly. The enzyme activity was strongly inhibited by heavy metal ions (Cu²⁺ and Ag²⁺) and EDTA. The purified enzyme from the transformed Pichia pastoris synthesized S-adenosylmethionine (SAM) from ATP and l-methionine in vitro with a K _m of 120 and 330 μM and V _max of 8.1 and 23.2 μmol/mg/min for l-methionine and ATP, respectively.     

Purification and properties of aminoaldehyde dehydrogenase from <Emphasis Type="Italic">Avena</Emphasis><Emphasis Type="Italic">sativa</Emphasis>

NAD-dependent aminoaldehyde dehydrogenase (AMADH, EC 1.2.1.-) from Avena shoots was purified by DEAE Sephacel, hydroxyapatite, 5′-AMP Sepharose 4B, Mono Q, and TSK-GEL column chromatographies to homogeneity by the criterion of native PAGE. SDS–PAGE yielded a single band at a molecular mass of 55 kDa. IEF studies showed a band with a pI value of 5.3. In contrast to AMADHs from other species, the TSK-GEL chromatography showed that Avena AMADH exists as a monomer in the native state. The purified enzyme catalyzed the oxidations of 3-aminopropionaldehyde (APAL), 4-aminobutyraldehyde (ABAL) N-(3-aminopropyl)-4-aminobutyraldehyde (APBAL), and 4-guanidinobutyraldehyde (GBAL), but not of betaine aldehyde or indoleacetaldehyde. The K _m values for APAL, ABAL, and GBAL were 1.5×10^–6, 2.2×10^–6, and 1.3×10^–5 M, respectively. Although N-terminal amino acid sequence of Avena AMADH could not be determined due to a modification of the amino residue, the sequence of the fragment of AMADH cleaved by V8 protease showed greater similarity to the barley BADH than to the pea AMADH. Electronic Publication     

Regional patterns in the invasion success of <Emphasis Type="Italic">Cheiracanthium</Emphasis> spiders (Miturgidae) in vineyard ecosystems

Invasions have often been linked to reduced biodiversity, but the role of non-native species in the decline of native species is ambiguous. In a 2003 survey of four California vineyard regions, exotic spiders (Cheiracanthium spp.) were more dominant in vineyards with lower spider species diversity and reduced spider abundance. There was no evidence for the role of species interactions in the invasion of Cheiracanthium spiders, however, as native spiders from the same feeding guild were most abundant in regions with high Cheiracanthium levels. Comparison with a survey conducted 10 years earlier indicated that the recent invader C. mildei simply represented an addition to the spider community, with no apparent change in proportions of the congener C. inclusum. Invasion success is discussed with respect to agricultural habitat, as results suggest that disturbed conditions in many vineyards may favor Cheiracanthium spp. and native wandering spiders while decreasing overall spider diversity.