Alfalfa cut at sundown and harvested as baleage improves milk yield of late-lactation dairy cows

Alfalfa (Medicago sativa L.) cut at sundown has been shown to contain greater concentration of total nonstructural carbohydrates (TNC) than that cut at sunup. Fourteen multiparous (8 ruminally cannulated) and 2 primiparous lactating dairy cows were randomly assigned to 2 treatments in a crossover design (2 periods of 24 d) to investigate the effects of alfalfa daytime cutting management on ruminal metabolism, nutrient digestibility, N balance, and milk yield. Half of each alfalfa field (total of 3 fields) was cut at sundown (PM) after a sunny day, whereas the second half was cut at sunup (AM) on the following day. Both PM and AM cuts were field-wilted and harvested as baleage (531 +/- 15.0 g of dry matter/kg of fresh matter). Bales (PM and AM) were ranked according to their concentrations of TNC, paired, and each pair of PM and AM baleages was then assigned to each experimental day (total of 48 d). The difference in TNC concentration between PM and AM baleages fed during the 10 d of data and sample collection varied from -10 to 50 g/kg of dry matter. Each pair of baleage was fed ad libitum to cows once daily with no concentrate. Ruminal molar proportion of acetate and total volatile fatty acid concentration were greater in animals fed the AM baleage, whereas the proportion of valerate was greater with PM baleage; no other significant changes in ruminal molar proportions of volatile fatty acids were observed between forage treatments. Digestible organic matter intake, organic matter digestibility, and plasma Lys concentration were significantly greater in cows fed PM alfalfa, suggesting that more nutrients were available for milk synthesis. Significantly lower body weight gain and retained N as a proportion of N intake were observed in cows fed PM alfalfa, thus suggesting that nutrients were channeled to milk synthesis rather than to body reserves. Intake of dry matter (+1.0 kg/d), and yields of milk (+1.0 kg/d), milk fat (+70 g/d), and milk protein (+40 g/d) were significantly greater in cows fed PM vs. AM alfalfa. Concentration of milk urea N and excretion of urea N as a proportion of total urinary N were significantly reduced, and milk N efficiency was increased when feeding PM vs. AM alfalfa, indicating an improvement in N utilization. Increasing the TNC concentration of alfalfa by shifting forage cutting from sunup to sundown improved N utilization and milk production in late-lactation dairy cows.

Cadmium accumulation and its effect on the in vitro growth of woody fleabane and mycorrhized white birch

The effect of Cd on woody fleabane (Dittrichia viscosa (L.) Greuter) and white birch (Betula celtiberica Rothm. & Vasc.) was examined. Woody fleabane and white birch were grown in vitro in Murashige, T., Skoog, F., [1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473-479] (MS) plus Cd (10 mg Cd kg(-1)) and except for root length in white birch, plant development was inhibited when Cd was added. Cd accumulation in above-ground tissues showed differences among clones, reaching 1300 and 463 mg Cd kg(-1) dry wt. in selected clones of woody fleabane and white birch, respectively. Tolerance of Paxillus filamentosus (Scop) Fr. to Cd was also examined before mycorrhization. Plants of mycorrhized white birch grown in the presence of Cd had a better development and accumulated more Cd in their shoots than the non-mycorrhized ones. The use of selected clones of woody fleabane and the mycorrhization of white birch enhance extraction efficiency from contaminated soils in phytoremediation programs.

Comparison of optimized and standard diffusion-weighted imaging at 1.5T for the detection of acute lesions in patients with transient ischemic attack

SUMMARY

The high rate of normal diffusion-weighted imaging (DWI) in patients with transient ischemic attack (TIA) raises the question as to its sensitivity for detecting small ischemic lesions. We compared standard and optimized DWI in 36 consecutive patients with TIA. Optimized DWI was positive in more patients than standard DWI (19 versus 16; P < .001) and showed more lesions (56 versus 42; P = .002). At 1.5T, optimizing DWI decreases the rate of false-negative DWI in patients with TIA.

[Diffusion-weighted imaging of the brain: normal patterns, traps and artifacts]

Owing to its rapid acquisition time and high sensitivity, diffusion-weighted imaging has turned into a routine sequence for brain imaging. This is the case not only for stroke, but also for various diseases such as abscesses or tumors. Being aware of the artifacts is important for optimal interpretation. After a brief review of the normal patterns, the most frequent artifacts, inherent to the echoplanar imaging technique, are described and we provide suggestions to avoid them. Most current traps are caused by T2-weighting of the diffusion images; the key for avoiding erroneous interpretation relies on the ADC map.

Schnitzler's syndrome: 3-year radiological follow-up

Schnitzler's syndrome comprises urticaria, monoclonal gammapathy, inflammatory signs (fever, enlarged lymph nodes, hyperleukocytosis), and bone lesions. We report the imaging findings and follow-up of a new case with extensive osteosclerosis of the iliac bone, associated with inflammatory signal changes on MRI and foci of increased uptake on bone scintigraphy. When a diagnosis of Schnitzler's syndrome is established, treatment should be towards symptoms only; a long follow-up is warranted, as a delayed evolution towards a lymphoproliferative syndrome is possible.

Conformation study of HA(306-318) antigenic peptide of the haemagglutinin influenza virus protein

Several HLA-DR alleles present the immunodominant HA(306-318) peptide of haemagglutinin of the influenza virus to T cells. NMR data of the peptide in various water solutions exclude any alpha-helix or turn conformations. Circular dichroism and Fourier transform infrared spectroscopies indicate an estimated beta-extended structure in water of 31% and 28%, respectively, with spectra shape similar to the ones observed for beta-sheet containing proteins. The H/D amide exchange suggests a stable length-dependent interchain hydrogen-bonding. The partially beta-extended conformation of HA(306-318) in solution might be close to the one found in HA(306-318)-HLA-DR1 complex. These results suggest different interconverting extended conformations of HA(306-318), depending on the microenvironment of the solution medium. This flexibility emphasizes the ability of some peptides to fit more easily the binding site of several HLA-DR molecules. Similar results were obtained on the HIV P25(263-277) peptide which has been previously shown to be a good DR1 binder. From a vibrational point of view, infrared Amide I frequencies of secondary structures in peptides were ascertained. As previously demonstrated for proteins in solution, Fourier transform infrared and circular dichroism spectroscopies appear to be valuable tools for conformational properties of peptides. Their use may contribute to the detection of peptide conformation-binding relationship which has to be further tested by biochemical and biological studies.

Vanillin production from simple phenols by wine-associated lactic acid bacteria

AIMS

The ability of lactic acid bacteria (LAB) to metabolize certain phenolic precursors to vanillin was investigated.

METHODS AND RESULTS

Gas chromatography-mass spectrometry (GC-MS) or HPLC was used to evaluate the biosynthesis of vanillin from simple phenolic precursors. LAB were not able to form vanillin from eugenol, isoeugenol or vanillic acid. However Oenococcus oeni or Lactobacillus sp. could convert ferulic acid to vanillin, but in low yield. Only Lactobacillus sp. or Pediococcus sp. strains were able to produce significant quantities of 4-vinylguaiacol from ferulic acid. Moreover, LAB reduced vanillin to the corresponding vanillyl alcohol.

CONCLUSIONS

The transformation of phenolic compounds tested by LAB could not explain the concentrations of vanillin observed during LAB growth in contact with wood.

SIGNIFICANCE AND IMPACT OF THE STUDY

Important details of the role of LAB in the conversion of phenolic compounds to vanillin have been elucidated. These findings contribute to the understanding of malolactic fermentation in the production of aroma compounds.

Responses of Picea mariana to elevated CO2 concentration during growth, cold hardening and dehardening: phenology, cold tolerance, photosynthesis and growth

Seedlings from a northern and a southern provenance of black spruce (Picea mariana Mill. BSP) from eastern Canada were exposed to 37 or 71 Pa of carbon dioxide (CO2) during growth, cold hardening and dehardening in a greenhouse. Bud phenology, cold tolerance and photosynthetic efficiency were assessed during the growing and over-wintering periods. Bud set occurred earlier in elevated [CO2] than in ambient [CO2], but it was later in the southern provenance than in the northern provenance. An increase in seedling cold tolerance in early fall was related to early bud set in elevated [CO2]. Maximal photosystem II (PSII) photochemical efficiency (F(v)/F(m)), effective quantum yield (phi(PSII)), photochemical quenching (q(P)), light-saturated photosynthesis (Amax), apparent quantum efficiency (alpha'), light-saturated rate of carboxylation (Vcmax) and electron transport (Jmax) decreased during hardening and recovered during dehardening. Although Amax and alpha' were higher in elevated [CO2] when measured at the growth [CO2], down-regulation of photosynthesis occurred in elevated [CO2] as shown by lower F(v)/F(m), phi(PSII), Vcmax and Jmax. Elevated [CO2] reduced gene expression of the small subunit of Rubisco and also decreased chlorophyll a/chlorophyll b ratio and nitrogen concentration in needles, confirming our observation of down-regulation of photosynthesis. Elevated [CO2] increased the CO2 diffusion gradient and decreased photorespiration, which may have contributed to enhance Amax despite down-regulation of photosynthesis. Total seedling dry mass was higher in elevated [CO2] than in ambient [CO2] at the end of the growing season. However, because of earlier bud formation and cold hardening, and down-regulation of photosynthesis during fall and winter in elevated [CO2], the treatment difference in dry mass increment was less by the end of the winter than during the growing season. Differences in photosynthetic rate observed during fall, winter and spring account for the inter-annual variations in carbon assimilation of black spruce seedlings: our results demonstrate that these variations need to be considered in carbon budget studies.

Growth, compatible solute and salt accumulation of five mycorrhizal fungal species grown over a range of NaCl concentrations

The oil sand industry in northeastern Alberta produces vast areas of severely disturbed land. The sodicity of these anthropic soils is one of the principal constraints that impede their revegetation. Previous in vitro studies have shown that the ectomycorrhizal fungi Laccaria bicolor (Maire) Orton UAMH 8232 and Hebeloma crustuliniforme (Bull) Quel. UAMH 5247 have certain salt-resistant traits and thus are candidate species for the inoculation of tree seedlings to be outplanted on salt-affected soil. In this study, the in vitro development of these fungi was compared to that of three mycorrhizal fungi [Suillus tomentosus (Kauff.) Sing., Snell and Dick; Hymenoscyphus sp. and Phialocephala sp.] isolated from a sodic site created by Syncrude Canada Ltd. Their growth, osmotica and Na/Cl contents were assessed over a range (0, 50, 100, 200 mM) of NaCl concentrations. After 21 days, the two ascomycetes (Hymenoscyphus sp. and Phialocephala sp.) were shown to be more resistant to the NaCl treatments than the three basidiomycete species. Of the basidiomycetes, L. bicolor was the most sensitive to NaCl stress, while H. crustuliniforme showed greater water stress resistance, and the S. tomentosus isolate exhibited greater Na and Cl filtering capacities and had a better biomass yield over the NaCl gradient tested. Both ascomycetes used mechanisms other than carbohydrate accumulation to palliate NaCl stress. While the Hymenoscyphus isolate accumulated proline in response to NaCl treatments, the darker Phialocephala isolate may have used compounds such as melanin. The basidiomycete species accumulated mainly mannitol and/or proline in response to increasing concentrations of NaCl.

[Hereditary Creutzfeldt-Jakob disease caused by a mutation at codon 200]

INTRODUCTION

A typical case of genetic Creutzfeldt-Jakob disease in a 39-year-old woman without remarkable familial history is described.

CASE REPORT

Initial symptoms were disequilibrium, cerebellar syndrome and complex neurovisual complaints. EEG was pseudoperiodic. NSE and 14-3-3 protein levels were elevated in the CSF. MRI showed anomalies of the anterior parts of the putamen and the caudate nuclei on the MRI T2 FLAIR sequence, mainly on diffusion sequences. A quinacrine test did not yield any effect. Death eventually occurred 8 months after the first symptoms.

CONCLUSION

Current data on genetic Creutzfeldt-Jakob disease are briefly reviewed.

Methionine catabolism and production of volatile sulphur compounds by OEnococcus oeni

AIMS

During malolactic fermentation (MLF), the secondary metabolisms of lactic acid bacteria (LAB) contribute to the organoleptic modification of wine. To understand the contribution of MLF, we evaluated the capacity of various wine LAB to metabolize methionine.

METHODS AND RESULTS

Using gas chromatography (GC) coupled either with mass spectrometry (MS) or a flame photometry detector in sulphur mode (FPD), we studied this metabolism in laboratory media and wine. In laboratory media, several LAB isolated from wine were able to metabolize methionine. They formed methanethiol, dimethyl disulphide, 3-(methylsulphanyl)propan-1-ol and 3-(methylsulphanyl)propionic acid. These are known to have powerful characteristic odours and play a role in the aromatic complexity of wine. In various red wines, after MLF only the 3-(methylsulphanyl)propionic acid concentration increased significantly, as verified with several commercial starter cultures. This compound, which is characterized by chocolate and roasted odours, could contribute to the aromatic complexity produced by MLF.

CONCLUSIONS

This study shows that LAB isolated from wine, especially OEnococcus oeni strains, the major species in MLF, are able to metabolize methionine to form volatile sulphur compounds.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to demonstrate the capacity of wine LAB to metabolize methionine.

[Case history of mitochondrial cytopathy with cardiac expression]

Childhood dilated cardiomyopathies comprise a wide aetiological spectrum for which the prognosis and treatment sometimes vary considerably. We report the case of a patient affected by a rare form of mitochondrial cardiomyopathy in whom the diagnosis of acute myocarditis had initially been made. The progression was fatal even though the patient was awaiting a cardiac transplant. Beyond the difficulties of diagnosis and treatment of this pathology, this clinical case underlines the significance of an early aetiological diagnosis based on the results of an endo-myocardial biopsy. Cardiac transplantation should be envisaged for this type of patient based not only on the clinical status but equally by taking account of the prognosis of this disease for which deterioration can sometimes be very rapid.

HLA-G unique promoter region: functional implications

In contrast to the highly polymorphic HLA class Ia genes that exhibit a broad somatic tissue distribution, the restricted constitutive expression of HLA-G to trophoblast and a subset of thymic epithelial cells suggests tight transcriptional control of this MHC class Ib gene. Transactivation of MHC class I genes is mediated by three major regulatory modules present in their promoter region namely enhancer A, ISRE, and SXY. The 220-bp promoter sequence of HLA-G comprises modified enhancer A and SXY modules and lacks the ISRE which renders this gene unresponsive to NK-kappaB, IRF1, and class II transactivator DNA-binding factors. A number of other HLA-G upstream regulatory elements have recently been described. Using different transgenic HLA-G mouse models under the control of the HLA-G promoter, several groups have shown by in situ hybridization and/or qualitative or quantitative RT-PCR that constitutive HLA-G transcriptional expression in placental tissue decreased with gestational time. This suggests that once the placenta is fully formed, the functions of HLA-G might not be so crucial.

Detection and prediction of acute heart transplant rejection with the myocardial T2 determination provided by a black-blood magnetic resonance imaging sequence

OBJECTIVES

This study aimed to determine whether the myocardial T2 relaxation time, determined using a black-blood magnetic resonance imaging (MRI) sequence, could predict acute heart transplant rejection.

BACKGROUND

The use of black-blood MRI sequences allows suppression of the confusing influence of blood signal when myocardial T2 is calculated to detect myocardial edema.

METHODS

A total of 123 investigations, including cardiac MRI and myocardial biopsy, were performed 8 +/- 11 months after heart transplantation. Myocardial T2 was determined using an original inversion-recovery/spin-echo sequence.

RESULTS

A higher than normal T2 (> or = 56 ms) allowed an accurate detection of the moderate acute rejections evidenced at baseline biopsy (> or = International Society for Heart and Lung Transplantation grade 2): sensitivity, 89% and specificity, 70% (p < 0.0001). T2 was increased in grade 2 (n = 11) compared with grade 0 (n = 49, p < 0.05), grade 1A (n = 34, p < 0.05) and grade 1B (n = 21, p < 0.05); T2 was further increased in grade 3 (n = 8) compared with grade 2 (p < 0.05). In addition, in patients without rejection equal to or greater than grade 2 at baseline, a T2 higher than normal (> or = 56 ms) was correlated with the subsequent occurrence of equal or greater than grade 2 rejection within the next three months: sensitivity 63% (12/19) and specificity 78% (64/82) (p = 0.001).

CONCLUSIONS

Myocardial T2 determined using a black-blood MRI sequence, is sufficiently sensitive to identify most of the moderate acute rejections documented with biopsy at the same time, but is also a predictor of the subsequent occurrence of such biopsy-defined rejections.

High frequency stimulation of the subthalamic nucleus increases the extracellular contents of striatal dopamine in normal and partially dopaminergic denervated rats

The subthalamic nucleus (STN) has come under focus in Parkinson disease (PD) because of recent advances in the understanding of the functional organization of the basal ganglia in normal and pathological conditions. Manipulations of the STN have been described to compensate for some imbalance in motor output of the basal ganglia in animal models of PD and have been proposed as a potential therapeutic target in humans. Indeed, high frequency stimulation (HFS) (130 Hz) of the STN has beneficial effects in severe parkinsonian patients but the precise mechanisms underlying these clinical results remain to be elucidated. To date, very little is known concerning the effect of HFS-STN on striatal dopaminergic transmission. Since it has been reported that dopaminergic medication may be reduced in PD patients under HFS-STN, our goal was to study the effect of HFS-STN on striatal dopamine (DA) transmission by using intracerebral microdialysis in normal and partially DA denervated rats. Our results show that HFS STN induces a significant increase of extracellular DA in the striatum of normal and partially DA lesioned rats while striatal extracellular levels of DOPAC were not affected. We conclude that HFS-STN acts directly and/or indirectly on striatal DA levels in control or partially DA lesioned rats.

Role of botrytized grape micro-organisms in SO2 binding phenomena

AIMS

The purpose of this work was to study the involvement of micro-organisms, which develop together with Botrytis cinerea on grapes, in the SO2 binding power of musts.

METHODS AND RESULTS

Yeasts and bacteria were involved. Most bacteria were acetic acid bacteria, mainly of the Gluconobacter genus. Unlike oxidative yeasts, Gluconobacter produce gluconic acid (in balance with delta-gluconolactone) from glucose, 5-oxofructose from fructose and dihydroxyacetone from glycerol. Production of carbonyl compounds from other sugars and polyols was not detected or was very weak.

CONCLUSION

Acetic acid bacteria are responsible for the increases in SO2 binding power of musts from botrytized grapes by oxidizing the three main sugars of these grapes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Up to 80% of the SO2 binds with products of Gluconobacter which easily grow on 'botrytized' grapes. Depending on climatic conditions, some vintages are particularly difficult to stabilize.

Differentiation of the aromas of Merlot and Cabernet Sauvignon wines using sensory and instrumental analysis

The aromas of six Merlot and three Cabernet Sauvignon wines of the 1996 vintage from the Bordeaux region were evaluated by sensory analysis. A panel of selected enology students was trained to assess 20 attributes previously generated for these wines by enologists of Bordeaux. Using statistical methods, this 20-attribute list was reduced to a 12-attribute list. The aroma profiles of the wines of Merlot and Cabernet Sauvignon were very close. Differentiation of the wines of these two varieties was significant only for the caramel descriptor, which was rated higher in the Merlot wines. Gas chromatography/olfactometry (GC/O) and GC/MS analyses were used to detect and identify the potent odorants with the caramel odor in the two most differentiated samples for this attribute, a Merlot wine and a Cabernet Sauvignon wine. Two odorant zones with this odor resulted in identification of 4-hydroxy-2,5-dimethylfuran-3(2H)-one (HDMF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methylfuran-3(2H)-one (HEMF). Aroma extract dilution analysis (AEDA) method showed a higher dilution factor (FD) for HDMF in the Merlot wine extract than in the Cabernet Sauvignon extract. The HDMF levels determined in the wines studied using a stable isotope dilution assay (SIDA) method were consistent with the results found by sensory analysis and GC/O; i.e., higher HDMF levels were present in the Merlot wines than in the Cabernet Sauvignon wines.