Vulnerability of low temperature induced needle retention in balsam fir (Abies balsamea L.) to vapor pressure deficits

Low temperature (LT) exposure has been shown to delay postharvest needle abscission and senescence (NAS) in balsam fir and changes in vapor pressure deficit (VPD) are expected to alter these processes. Two and half year-old seedlings were exposed to a LT of 5°C for 15 days while the control (CT) group was maintained at 22°C. Seedlings were then exposed to four different VPD (0.22, 0.87, 1.3 and 1.86?kPa) and observed for relative water content (RWC), xylem pressure potential (XPP), membrane injury index (MII), stem capacitance (SC) and NAS. An interactive effect of LT and VPD was observed in RWC, XPP, MII and NAS. Low VPD (0.22 and 0.87?kPa) resulted in less negative XPP, lower electrolyte leakage, higher SC and ultimately higher NAS than those at high VPD. Maximum NAS was recorded at 0.22?kPa. At 1.86?kPa, LT had 5× lower RWC (13%), 3× more negative XPP (?1.1?MPa), 1.8× higher membrane damage and 35% lower NAS (47 days) than CT. The SC declined with an increase in VPD with no effect of LT. The XPP and RWC of LT seedlings showed a positive relationship with NAS with R² values of 0.54 and 0.59, respectively. LT offered no benefits to NAS at high VPD environments.     

Use of a commercial protease and yeasts to obtain CGRP-like molecules from saithe protein

Different bioactive molecules, such as CGRP-like peptides, can be found in fish protein hydrolysates. Calcitonin gene-related peptide (CGRP) is a neuropeptide known to act as a potent arterial and venous vasodilator in humans. This study focuses on the industrial obtaining of CGRP-like molecules from saithe (Pollachius virens) byproduct, derived from the filleting process. Protein from P. virens was primarily hydrolyzed with Alcalase and later treated with Saccharomyces cerevisiae live cells. Treatment with Saccharomyces doubled the quantity of bioactive molecules obtained. The CGRP-like molecules were partially purified by chromatography, and the immunoreactive material was further analyzed for its CGRP-like bioactivity, using a specific radioreceptor assay. The concentration of CGRP-like molecules increased over 100-fold after purification. The bioactive molecules were able to induce cyclic AMP stimulation in rat liver membranes. Finally, partial sequencing of the bioactive peptide was performed, showing some homology with alpha-actin and myosin of several fish species.     

Framework for intake simulation of functional ingredients

OBJECTIVE: To create a general framework for the simulation of intakes from mandatory or voluntary fortification, which will make outcomes of simulation studies more comparable and give insight on uncertainties. DESIGN: A general framework was developed based on methods used in already published case studies of mandatory fortification. The framework was extended to be suitable for the simulation of voluntary fortification. Case studies of folic acid fortification were used to illustrate the general framework. RESULTS: The developed framework consists of six steps. First, the definition of the fortification strategy (step 1), followed by the identification of potential carrier products (step 2), and the definition of fortification levels or ranges (step 3). Thereafter, virtual food/supplement composition data are created (step 4) and food/supplement consumption data are required (step 5). Finally, the intake of the functional ingredient from functional foods, other foods and dietary supplements is calculated during the simulation resulting in total habitual intake distributions (step 6). CONCLUSIONS: Simulation of both mandatory and voluntary folic acid fortification in The Netherlands showed that the general framework is applicable. Also with incomplete data or data from different sources, the (habitual) intake distributions can be estimated using assumptions, statistical procedures or probabilistic modelling approaches. It is important that the simulation procedure is described well, so that an insight on uncertainties and knowledge gaps to be filled is given.     

Can a problem-solving approach strengthen landscape ecology’s contribution to sustainable landscape planning?

The need to avert unacceptable and irreversible environmental change is the most urgent challenge facing society. Landscape ecology has the capacity to help address these challenges by providing spatially-explicit solutions to landscape sustainability problems. However, despite a large body of research, the real impact of landscape ecology on sustainable landscape management and planning is still limited. In this paper, we first outline a typology of landscape sustainability problems which serves to guide landscape ecologists in the problem-solving process. We then outline a formal problem-solving approach, whereby landscape ecologists can better bring about disciplinary integration, a consideration of multiple landscape functions over long time scales, and a focus on decision making. This framework explicitly considers multiple ecological objectives and socio-economic constraints, the spatial allocation of scarce resources to address these objectives, and the timing of the implementation of management actions. It aims to make explicit the problem-solving objectives, management options and the system understanding required to make sustainable landscape planning decisions. We propose that by adopting a more problem-solving approach, landscape ecologists can make a significant contribution towards realising sustainable future landscapes.     

Molecular and Biological Characterization of Lettuce mosaic virus (LMV) Isolates Reveals a Distinct and Widespread Type of Resistance-Breaking Isolate: LMV-Most

ABSTRACT Lettuce mosaic virus (LMV) causes an economically important seedborne and aphid-transmitted disease of lettuce and ornamental crops worldwide. The genetic diversity among 73 LMV isolates was examined based on a 216-nucleotide sequence at the variable region encoding the NIb-coat protein junction. Three clusters of LMV isolates were distinguished: LMV-Yar, LMV-Greek, and LMV-RoW. In the latter cluster, two subgroups of isolates, LMV-Common and LMV-Most, accounted for a large proportion of the LMV isolates analyzed. These two subgroups included the seedborne isolates, consistent with this property contributing a selective advantage and resulting in widespread distribution. In addition to being seedborne, LMV-Most isolates overcome the two resistance genes commonly used in lettuce, mo1(1) and mo1(2), and thus represent a potential threat to lettuce cultivation. The complete sequence of an LMV-Most isolate (LMV-AF199) was determined, allowing a better definition of the genetic relationships among LMV-Most, LMV-Common, and an additional isolate of the LMV-RoW cluster.     

Evaluation of the pollution by organochlorinated compounds (polychlorobiphenyls and pesticides) and metals (Cd,Cr, Cu and Pb) in the water and in the zebra mussel (Dreissena polymorpha pallas) of the river Seine.

The relationships between some organochlorines and metals in the water and in the zebra mussel of the river Seine have been studied in the Parisian area. The bioconcentration of PCBs by the mussel (Kb = 17 × 10³) was about 10 fold higher than for other organochlorines. The accumulation and the release response of the mussel to alterations of the water organochlorine levels occurred within a period smaller than 7 days. The correlation between the water and the mussel levels is highly significant for γHCH and PCBs (r=0.94, p<0.01 and r=0.87, p<0.05, respectively). The Pb bioconcentration (0.15 × 103) was about 20 fold lower than the Cu and Cr (3.4 and 3.0 × 10³, respectively). The Cu and the Pb levels in the water and in the mussel followed a parallel course. Cu and Pb appear to be taken up and released relatively rapidly within a 7 day period. Comparisons between the different stations along the river Seine showed that the highest pollutant evels in the water were found downstream Paris and were fairly well reflected by the mussel levels. However, when pollution reaches top values, the mussel metabolic activities are affected and thus, the bioconcentration ability too.     

Fructosamine

Fructosamines are glycated serum proteins that, depending on their life span, reflect glycemic control over the previous 2 to 3 weeks. The nitroblue tetrazolium reduction method adapted to autoanalysis appeared to be a practical means to assay fructosamine quickly, economically, and accurately. The upper limit of the reference range is 374 μmol/L in dogs (95% percentile) and 340 μmol/L in cats (95% percentile). Newly diagnosed diabetic dogs and cats that had not undergone previous insulin therapy had significantly higher fructosamine concentrations than nondiabetic animals. In diabetic dogs that were receiving insulin therapy, the fructosamine test reflected the glycemic state far more accurately than did individual blood glucose measurements. Animals with satisfactory metabolic control revealed fructosamine concentrations within the reference range, whereas fructosamine concentrations above 400 μmol/L indicated insufficient metabolic control. On the basis of fructosamine concentrations, cats with a transitory hyperglycemia and cats with diabetes mellitus were differentiated. The fructosamine test is a valuable parameter for the diagnosis and metabolic control of diabetes mellitus in dogs and cats.     

Reconstruction of the historical distribution ranges of imperilled stream fishes from a global endemic hotspot based on molecular data: Implications for conservation of threatened taxa

1. Understanding historical distribution patterns of freshwater fishes prior to human impacts is crucial for informing effective strategies for biodiversity conservation. However, incomplete information on species occurrence records, the existence of cryptic species and sensitivity to small sample sizes limit the application of historical records in natural history collections as well as conventional species distribution modelling algorithms to infer past distributions of species.
2. This study used molecular data as an alternative and objective approach to reconstruct the historical distribution ranges of four stream fishes from the Breede River system in the Cape Fold Ecoregion, a global hotspot of imperilled endemic freshwater biodiversity in southern Africa.
3. The study used 249 occurrence records and 208 mitochondrial cytochrome b sequences to reconstruct the potential historical ranges of four taxa: Galaxias sp. ‘zebratus nebula', Galaxias sp. ‘zebratus Riviersonderend', Pseudobarbus sp. ‘burchelli Breede' and Pseudobarbus skeltoni.
4. All four taxa historically had broader distribution ranges across the Breede River system before human impacts, but they have suffered severe attrition as the main‐stem populations have been extirpated.
5. The severe decline in the historical ranges of these four taxa is a result of multiple impacts, particularly hydrological modification, habitat degradation and the introduction of non‐native species, which are also global challenges for freshwater ecosystems.
6. The approach presented in this study has great potential for reconstructing historical ranges of stream‐dwelling taxa from disparate regions where fragmentation has resulted from human‐mediated impacts. This information is crucial for identifying appropriate conservation strategies such as river rehabilitation and eradication of non‐native species, as well as guiding reintroductions and informing assisted gene flow where these are deemed necessary interventions.

     

Modification of Campylobacterjejuni Broiler Colonization by a Feed Additive Composed of Encapsulated Organic Acids and Essential Oils

The objective of this study was to evaluate the effect of a novel feed additive on chicken intestinal colonization and carcass contamination by Campylobacterjejuni. The feed additive was composed of microencapsulated organic acids and essential oils （OA/EO）. The feed additive tested was provided by Jefo Nutrition Inc., St-Hyacinthe, Quebec, Canada. Day-old birds were separated into two rooms and subdivided into two groups. Chicken were fed with OA/EO or not fed with OA/EO until they reached 35 d of age. At 14 d of age, chickens received an oral suspension of two well characterized C. jejuni strains, depending on the room they were housed in. The levels of C. jejuni were periodically monitored in the caecum and on the carcasses. C. jejuni colonization was further characterized by the use of high-resolution melt analysis of the C. jejuniflaA gene （HRM-flaA）. The effect of the feed additive was strain-dependent. In room two, the feed additive had no effect on the caecal counts. In room one, at 35 d of age, caecal C. jejuni counts were higher with OA/EO, as opposed to carcasses counts which were lower in the treated group. The HRM-flaA analysis showed that an amplification profile was predominant in birds fed with OA/EO at 35 d of age in room one, suggesting the selection of a C. jejuni strain. In conclusion, the OA/EO seemed to be effective to reduce C. jejuni levels but this effect appeared strain dependent.     

Criteria for selecting productive and stable pea cultivars

The beginning and duration of the seed set in the growth cycle determine the level and stability of the yield of a pea (Pisum sativum L.) genotype. The objective of the present study was to identify criteria for selecting genotypes, both in terms of timing of seed set and productivity. Genotypes were initially compared in field experiments for two different levels of inter-plant competition, but using the same photo-thermal conditions. These experiments showed that the initiation and, particularly, the duration of seed set were affected by plant growth rates, indicating that selection on these variables must be done by comparing genotypes under regular cropping conditions. When measuring seed production of the whole plant, we found that mean dry seed weight per podded node all over the plant and the number of podded nodes on any fertile stem were similar to those on the main stem. These results confirmed that branches and main stems have a similar reproductive pattern, and thus that any podded stem of the canopy is representative of every stem of the plant. Lastly, we showed that, when associated, the number of podded nodes, the mean dry seed weight per podded node on the main stem (or on any reproductive stem of the canopy), and the number of basal branches per plant are suitable criteria for selecting for productivity among genotypes with a similar duration of seed set. This revised version was published online in August 2006 with corrections to the Cover Date.