Ultrastructure of steam-exploded wood

Summary The ultrastructure of steam-exploded wood from the softwood Pinus radiata D. Don was examined by electron microscopy in order to determine the reasons for increased porosity and enhanced susceptibility to enzymatic hydrolysis. Ultrastructural changes were observed in the form of lignin redistribution and swelling of the cellulose framework. Lignin showed evidence of melting, having contracted into well defined agglomerates suspended in a web of cellulose. Using lanthanum and gold tracers of known particle size the pores in the microfibrillar cell wall have been examined. Cellulose regions were shown to contain numerous pores greater than 2 nm, while lignin agglomerates did not contain such pores. Treatment with NaOH resulted in lignin being smeared over the porous cell wall material — hence blocking pores and reducing digestibility.The authors gratefully acknowledge the assistance of T. A. Clark and K. F. Deverell during the course of this work     

Evaluation of propofol and medetomidine-ketamine for short-term immobilization of Gulf of Mexico sturgeon (Acipenser oxyrinchus de soti).

Parenteral anesthetic protocols for short-term immobilization were evaluated in twenty 4-yr-old Gulf of Mexico sturgeon (Acipenser oxyrinchus de soti). An initial dose-response trial determined the efficacy of either propofol (3.5-7.5 mg/kg. i.v.) or combinations of medetomidine (0.03-0.07 mg/kg, i.m.)-ketamine (3-7 mg/kg, i.m.). A subsequent study evaluated the physiologic effects of propofol (6.5 mg/kg, i.v.)-induced anesthesia and anesthesia induced with a medetomidine (0.06 mg/kg, i.m.)-ketamine (6 mg/kg i.m.) combination. The effects of medetomidine were reversed at 30 min with atipamezole (0.30 mg/kg, i.m.). Both drug protocols provided adequate short-term immobilization for minor diagnostic procedures. Sturgeon receiving propofol were in a light plane of anesthesia within 5 min after drug administration, whereas only 30% of the medetomidine-ketamine group reached a light plane of anesthesia in the same time period. Both propofol and medetomidine-ketamine resulted in mild bradycardia and apparent respiratory depression, with propofol producing more profound effects. At the dosages used in this study, both propofol and the medetomidine-ketamine combination effectively induced a light plane of anesthesia. Induction times were shorter in the propofol group.     

Constrained map-based inventory estimation

A region can conceptually be tessellated into polygons at differentscales or resolutions. Likewise, samples can be taken from theregion to determine the value of a polygon variable for eachscale. Sampled polygons can be used to estimate values for otherpolygons at the same scale. However, estimates should be compatibleacross the different scales. Estimates are often required forzones within a region, where a region might be a state and countiescould be the zones. A method is developed for estimating high-resolution(pixel) values that are constrained to be compatible with resultsfor lower resolution values. The high-resolution values areconstrained to sum to totals for zones within a region, wherethe totals are being simultaneously estimated from measurementstaken at a different scale. If the zone estimates are unbiased,then the pixel-based estimates for the zone will be less biased.Sums of pixels in arbitrary polygons are thereby constrainedto approach unbiased estimates. Approximate variance estimatorsare developed for the summed pixel estimates. Two example applicationsare provided. The first example is based on simulated data andverifies that the proposed variance estimators give reasonableresults. The second example estimates the volume in a circlearound a possible mill site in North Carolina. This exampleuses publicly available US Forest Service inventory data andsimulated inventory data that the mill would provide.     

Flavonoids from Blumea balsamifera

3,4',5-Trihydroxy-3',7-dimethoxyflavanone was isolated from the ligroin extract of the leaves of Blumea balsamifera, while the acetone extract yielded 3',4',5-trihydroxy-7-methoxyflavanone and a new biflavonoid identifed as 3-O-7'-biluteolin (1). The isolation of 1 is significant since a biflavonoid with a C-O-C linkage of the type [I-3-O-II-7] has not been previously reported from a plant.     

Physiological traits of two Populus x euramericana clones,Luisa Avanzo and Dorskamp,during a water stress and re-watering cycle

We compared responses to drought and re-watering of greenhouse-grown cuttings of Populus x euramericana (Dode) Guinier clones, Luisa Avanzo and Dorskamp. Total leaf area, leaf number, leaf area increment and stomatal conductance were evaluated periodically during a 29-day drought period and for 16 days after re-watering. Soil water content and predawn leaf water potential (Psi(wp)) were measured on Days 29 and 45. On the same days, relative water content (RWC), specific leaf area (SLA), nitrogen, chlorophyll, soluble sugars, total phenols, flavanols and antioxidant activity were determined for leaves taken from the bottom to the top of each cutting. Leaves of Luisa Avanzo cuttings grew more rapidly than leaves of Dorskamp and exhibited higher SLA, but lower concentrations of nitrogen, chlorophyll and soluble sugars and lower antioxidant activity per unit area. On Day 29, after withholding water, both clones had closed their stomata, reduced rates of leaf growth, and lower Psi(wp) and RWC; however, the clones differed in their responses to soil water depletion. Compared to Dorskamp, Luisa Avanzo closed its stomata earlier and maintained higher Psi(wp), but lower RWC and leaf sugar concentrations. Antioxidant activity of leaf methanolic extracts decreased in response to water stress only in Luisa Avanzo. Leaf physiology and its modulation by water stress were age dependent in Luisa Avanzo.     

QTL mapping of BNYVV resistance from the WB258 source in sugar beet

Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV), is an important sugar‐beet disease worldwide. The aim of this study was to investigate and map BNYVV resistance from the WB258 source. Presence of a major resistance gene (termed Rz5) was indicated by ～1 : 1 segregation of virus levels in a population of 170 individuals derived from WB258. The maximum logarithm of odds (LOD) position for Rz5, identified by interval mapping, explained ～81% of the phenotypic variance. Rz5 was mapped alongside the previously identified Rz4 from the R36 source. Rz4 and Rz5 were located to 6.9 cM and 6.0 cM regions, respectively, on chromosome III by interval mapping. These locations corresponded well to the position of the widely deployed Rz1 gene, suggesting that the three genes could represent an allelic series. Physical mapping is probably required to confirm this however. BNYVV resistance genes from novel sources are potentially important in breeding for more durable resistance either as separate genes or as BNYVV race‐specific alleles.     

The use of a geographical information system for land-based aquaculture planning

Site selection for aquaculture planning is a complex task involving the identification of areas that are economically, socially and environmentally suitable, available to aquaculture and commercially practicable. This paper reports upon a study into the use of a geographic information system (GIS) to assist in aquaculture planning. Using a case study in the site selection for land‐based shrimp farming within the Australian coastal zone, we demonstrate that a GIS has potential to assist aquaculture planning. Our analysis is based on a sequential, two‐stage approach. The first stage eliminates the grossly unsuitable portion of the study area through a preselection with low resolution, cheap and easily available data. The second stage then focuses on and ranks the remaining area using high resolution, possibly more expensive data. Finally, we use the GIS to present the results of the analysis in an easily accessible form.     

The extinction risk of New Zealand chondrichthyans

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