Soil [N] modulates soil C cycling in CO2‐fumigated tree stands: a meta‐analysis

Under elevated atmospheric CO₂ concentrations, soil carbon (C) inputs are typically enhanced, suggesting larger soil C sequestration potential. However, soil C losses also increase and progressive nitrogen (N) limitation to plant growth may reduce the CO₂ effect on soil C inputs with time. We compiled a data set from 131 manipulation experiments, and used meta‐analysis to test the hypotheses that: (1) elevated atmospheric CO₂ stimulates soil C inputs more than C losses, resulting in increasing soil C stocks; and (2) that these responses are modulated by N. Our results confirm that elevated CO₂ induces a C allocation shift towards below‐ground biomass compartments. However, the increased soil C inputs were offset by increased heterotrophic respiration (Rh), such that soil C content was not affected by elevated CO₂. Soil N concentration strongly interacted with CO₂ fumigation: the effect of elevated CO₂ on fine root biomass and –production and on microbial activity increased with increasing soil N concentration, while the effect on soil C content decreased with increasing soil N concentration. These results suggest that both plant growth and microbial activity responses to elevated CO₂ are modulated by N availability, and that it is essential to account for soil N concentration in C cycling analyses.     

Elbow-joint morphology as a guide to forearm function and foraging behaviour in mammalian carnivores

Among the hunting strategies employed by members of the order Carnivora (Mammalia), two, stalk and ambush and sustained pursuit, are particularly prevalent among larger species of the order. It has been difficult to identify morphological traits that support this distinction and ecological observations have shown that most carnivorans adopt a continuum of strategies, depending on available habitat and prey. In this paper, the shape of the distal humerus articulation is analysed, with the aim of exploring the use of the forelimb in prey procurement, and as a guide to such behaviour among fossil carnivorans. The results suggest that manual manipulation and locomotion are conflicting functions. Elbow‐joint morphology supports a division between grapplers (i.e. ambushers) and nongrapplers (i.e. pursuers). Joints of the former are characterized by being relatively wide and the latter, by being relatively narrow and box‐like with pronounced stabilizing features. At intermediate and large body sizes, carnivorans show a pattern suggesting mutually exclusive feeding strategies that involve either grappling with prey or sustained pursuit. The former allows for large body sizes, such as pantherine felids and ursids; the latter includes species of only moderate size, such as hyenids and canids. Elbow‐joint morphology is closely linked to phylogeny, but the morphology of the cheetah converges with that of nongrapplers, showing that strong selective forces may override the phylogenetic component. Two taxa of giant mustelids from the Miocene were analysed to test whether this sort of analysis is applicable to carnivorans of the past. The African Late Miocene species Ekorus ekakeran has a joint morphology comparable to that of modern‐day nongrapplers. Two joint morphologies were found in the North American Late Oligocene‐Early Miocene Megalictis ferox. The first morphology is comparable to that of modern pantherine cats and the second forms an intermediate between grapplers and nongrapplers that is not present in the modern carnivoran fauna. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 91–104.     

A KOREAN PERSPECTIVE ON DEVELOPING A GLOBAL POLICY FOR ADVANCE DIRECTIVES

Despite the wide and daunting array of cross‐cultural obstacles that the formulation of a global policy on advance directives will clearly pose, the need is equally evident. Specifically, the expansion of medical services driven by medical tourism, just to name one important example, makes this issue urgently relevant. While ensuring consistency across national borders, a global policy will have the additional and perhaps even more important effect of increasing the use of advance directives in clinical settings and enhancing their effectiveness within each country, regardless of where that country's state of the law currently stands. One cross‐cultural issue that may represent a major obstacle in formulating, let alone applying, a global policy is whether patient autonomy as the underlying principle for the use of advance directives is a universal norm or a construct of western traditions that must be reconciled with alternative value systems that may place lesser significance on individual choice. A global policy, at a minimum, must emphasize respect for patient autonomy, provision of medical information, limits to the obligations for physicians, and portability. And though the development of a global policy will be no easy task, active engagement in close collaboration with the World Health Organization can make it possible.     

Reproduction and probing behaviour of the bird cherry‐oat aphid Rhopalosiphum padi on detached leaves and leaves on intact seedlings of the winter host,bird cherry Prunus padus

Video recording and electrical penetration graph techniques are used simultaneously to investigate host acceptance (in terms of reproduction) and probing activities of autumn migrants (gynoparae) of the bird cherry‐oat aphid Rhopalosiphum padi (L.) on detached leaves and on leaves on intact plants of the winter host, bird cherry Prunus padus. There are no significant differences between the times taken to first parturition or the number of nymphs produced over a 6‐ or 18‐h period on intact plants or detached leaves. Stylet probing activities (i.e. total probe duration, xylem ingestion, the time to first phloem contact and phloem salivation) are also similar in the two situations.     

Enhanced production of 3,4-dihydroxybutyrate from xylose by engineered yeast via xylonate re-assimilation under alkaline condition

To realize lignocellulose-based bioeconomy, efficient conversion of xylose into valuable chemicals by microbes is necessary. Xylose oxidative pathways that oxidize xylose into xylonate can be more advantageous than conventional xylose assimilation pathways because of fewer reaction steps without loss of carbon and ATP. Moreover, commodity chemicals like 3,4-dihydroxybutyrate and 3-hydroxybutyrolactone can be produced from the intermediates of xylose oxidative pathway. However, successful implementations of xylose oxidative pathway in yeast have been hindered because of the secretion and accumulation of xylonate which is a key intermediate of the pathway, leading to low yield of target product. Here, high-yield production of 3,4-dihydroxybutyrate from xylose by engineered yeast was achieved through genetic and environmental perturbations. Specifically, 3,4-dihydroxybutyrate biosynthetic pathway was established in yeast through deletion of ADH6 and overexpression of yneI. Also, inspired by the mismatch of pH between host strain and key enzyme of XylD, alkaline fermentations (pH ≥ 7.0) were performed to minimize xylonate accumulation. Under the alkaline conditions, xylonate was re-assimilated by engineered yeast and combined product yields of 3,4-dihydroxybutyrate and 3-hydroxybutyrolactone resulted in 0.791 mol/mol-xylose, which is highest compared with previous study. These results shed light on the utility of the xylose oxidative pathway in yeast.     

Chilodonella spp. at Four Fish Farms in Northern Finland

A total of 4.1% infestation with Chilodonella spp. was found among fish studied in 144 tanks in 1987–1989, representing 14.0% of the tanks in which fish are reared at four salmonid farms in northern Finland. Two species were found, C. hexasticha and C. piscicola, and both occurred on salmon (Salmo salar L.), sea trout [S. trutta m. trutta (L.)] and brown trout [S. t. m. lacustris (L.)]. Variability was observed in the length and width of the C. piscicola specimens and the number of ciliary rows or kineties. Large specimens which had more kinetics than average for C. piscicola were found mainly on the skin of salmon aged 1–2 years. The number of kinetics in the right ciliary band was found in stepwise logistic regression analysis to be of importance when typing C. piscicola specimens. Fingerlings were found to be more susceptible to Chilodonella infestation than older fish, and mortality varied in the range 2–10% in the course of the epizootics in the three fish species. Most mortality cases were caused by C. hexasticha, occurring mainly on the gills of the fish. Chilodonella piscicola was most often found in salmon and occurred at lower water temperatures than C. hexasticha (mean water temperature when found for the first time being 13° C and 16° C, respectively).     

New Observations on the Choreotrich Ciliate Strombidinopsis acuminata Fauré-Fremiet 1924, and Comparison with Strombidinopsis jeokjo Jeong et al., 2004

ABSTRACT. A choreotrich ciliate collected in waters off Geoje Island, on the eastern coast of the South Sea of the southern coastal water of Korea was morphologically and biometrically investigated through observations of permanent preparations after protargol impregnations. Morphological data and ciliary patterns indicated that the ciliate should be identified as Strombidinopsis acuminata based on the number of somatic kineties. The vertical distribution of the population abundance was also examined in relation to environmental conditions: higher abundances occurred in surface water with higher temperature (22–23 °C), lower salinity (32 psu), and higher concentration (ca 10 μg/L) of chlorophyll a . The 18S rRNA gene of specimens from clonal cultures isolated from natural assemblages was sequenced. While this isolate of S. acuminata is closer to Strombidinopsis jeokjo (99.6–99.8%) than other isolates of S. acuminata (<99.0%), monophyly of S. acuminata was not rejected by the AU test. We discuss the discordance between morphological and molecular data for Strombidinopsis . In order to confirm the species level of the Strombidinopsis specimens, additional information is required based on genealogical analyses of multiple loci.     

Direct production of 4-hydroxybenzoic acid from cellulose using cellulase-displaying Pichia pastoris

4-hydroxybenzoic acid (4-HBA) is an industrially important aromatic compound, and there is an urgent need to establish a bioprocess to produce this compound in a sustainable and environmentally friendly manner from renewable feedstocks such as cellulosic biomass. Here, we developed a bioprocess to directly produce 4-HBA from cellulose using a recombinant Pichia pastoris strain that displays heterologous cellulolytic enzymes on its cell surface via the glycosylphosphatidylinositol (GPI)-anchoring system. β-glucosidase (BGL) from Aspergillus aculeatus, endoglucanase (EG) from Trichoderma reesei, and cellobiohydrolase (CBH) from Talaromyces emersonii were co-displayed on the cell surface of P. pastoris using an appropriate GPI-anchoring domain for each enzyme. The cell-surface cellulase activity was further enhanced using P. pastoris SPI1 promoter- and secretion signal sequences. The resulting strains efficiently hydrolyzed phosphoric acid swollen cellulose (PASC) to glucose. Then, we expressed a highly 4-HBA-resistant chorismate pyruvate-lyase (UbiC) from Providencia rustigianii in the cellulase-displaying strain. This strain produced 975 mg/L of 4-HBA from PASC, which corresponding to 36.8% of the theoretical maximum yield, after 96 h of batch fermentation without the addition of commercial cellulase. This 4-HBA yield was over two times higher than that obtained from glucose (12.3% of the theoretical maximum yield). To our knowledge, this is the first report on the direct production of an aromatic compound from cellulose using cellulase-displaying yeast.     

Components of male fitness in relation to body size in Epirrita autumnata (Lepidoptera, Geometridae)

Abstract. 1. The effect of body size on different components of male fitness was studied for Epirrita autumnata , a geometrid known for its eruptive population dynamics. Body size is the main determinant of female fecundity in this species.
2. Longevity of males was found to have a weak negative correlation with body size at low temperatures. No significant correlation was found at higher temperatures.
3. We found no correlation between male size and female fecundity or egg size which is consistent with the small size of spermatophores in this species.
4. Small and large males were equally successful when allowed to compete for females in laboratory conditions.
5. In one or two field collections, males found mating were larger than males found singly. Large males also had an advantage in finding of virgin females, offered experimentally. No size-assortative mating was recorded.
6. We conclude that size-dependent mate location ability is the factor accounting for most of the variance in male fitness in E.autumnata. The dependence of fitness on body size may well be equally strong in males and females.