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PubMed2004

Effect of alfalfa seed washing on the organic carbon concentration in chlorinated and ozonated water.

The bioassays assimilable organic carbon (AOC) and coliform growth response are better indexes than biological oxygen demand to determine water quality and water's ability to support the growth of bacteria. Ozonated (5 mg/liter) and chlorinated tap water were used to wash alfalfa seeds for 30 min. After washing in the ozonated tap water, the AOC concentration increased 25-fold, whereas the dissolved ozone decreased to undetectable levels. The AOC levels for the chlorinated water after washing the seeds also increased. These increases are due to ozone's strong oxidizing ability to break down refractory, large-molecular-weight compounds, forming smaller ones, which are readily used as nutrient sources for microorganisms. This same phenomenon was observed when using ozone in the treatment of drinking water. The AOC value increased from 1,176 to 1,758 micrograms C-eq/liter after the reconditioned wastewater was ozonated. When the ozonated wastewater was inoculated with Salmonella serotypes, the cells survived and increased generation times were observed. The increased nutrients would now become more readily available to any pathogenic microorganisms located on alfalfa seed surface as seen with the increase in the inoculated levels of Salmonella in the ozonated wastewater. If the washing process using ozonated water is not followed by the recommended hypochlorite treatment or continually purged with ozone, pathogen growth is still possible.

Area Under Curve↗
PubMed2005

A simple method for the direct detection of Salmonella and Escherichia coli O157:H7 from raw alfalfa sprouts and spent irrigation water using PCR.

The U.S. Food and Drug Administration recognizes that raw seed sprouts are an important cause of foodborne disease and is now recommending that either spent irrigation water or final product be screened for Salmonella and Escherichia coli O157:H7 as a means of assuring the safety of product intended for consumption. In an effort to streamline such testing efforts, a simple method to preconcentrate pathogens from sprouts and spent irrigation water was investigated to facilitate the direct (without prior cultural enrichment) detection of pathogens using the PCR technique. Alfalfa sprouts and spent irrigation water were seeded with Salmonella enterica serovar Typhimurium and E. coli O157:H7 at 10(-1) to 106 CFU/g or CFU/ml, respectively. Samples were blended (sprouts only) and then centrifuged at high speed to sediment the total bacterial population. The precipitate was processed for DNA isolation, PCR amplification, and amplicon confirmation by Southern hybridization. Mean pathogen recoveries after centrifugation ranged from 96 to 99% for both pathogens in both matrices. Using primers targeting the invA gene for Salmonella Typhimurium and the stx genes of E. coli O157:H7, it was possible to detect both pathogens in alfalfa sprouts at seeding concentrations as low as 10 CFU/g. PCR detection limits for both pathogens from spent irrigation water were 10(-1) CFU/ml, the equivalent of 100 CFU/liter of water. Because spent irrigation water is constitutionally simple, it is particularly well suited for bacterial concentration by simple centrifugation steps. In this study, progress was made toward development of a rapid, inexpensive, and sensitive method for the detection of sprout-associated pathogens that is relevant to current industrial practices and needs.

Colony Count, Microbial↗
PubMed2006

Inactivation of Escherichia coli O157:H7, Salmonella typhimurium DT104, and Listeria monocytogenes on inoculated alfalfa seeds with a fatty acid-based sanitizer.

Alfalfa seeds were inoculated with a three-strain cocktail of Escherichia coli O157:H7, Salmonella enterica subsp. enterica serovar Typhimurium DT104, or Listeria monocytogenes by immersion to contain approximately 6 to 8 log CFU/g and then treated with a fatty acid-based sanitizer containing 250 ppm of peroxyacid, 1,000 ppm of caprylic and capric acids (Emery 658), 1,000 ppm of lactic acid, and 500 ppm of glycerol monolaurate at a reference concentration of 1X. Inoculated seeds were immersed at sanitizer concentrations of 5X, 10X, and 15X for 1, 3, 5, and 10 min and then assessed for pathogen survivors by direct plating. The lowest concentration that decreased all three pathogens by >5 log was 15. After a 3-min exposure to the 15X concentration, populations of E. coli O157:H7, Salmonella Typhimurium DT104, and L. monocytogenes decreased by >5.45, >5.62, and >6.92 log, respectively, with no sublethal injury and no significant loss in seed germination rate or final sprout yield. The components of this 15x concentration (treatment A) were assessed independently and in various combinations to optimize antimicrobial activity. With inoculated seeds, treatment C (15,000 ppm of Emery 658, 15,000 ppm of lactic acid, and 7,500 ppm of glycerol monolaurate) decreased Salmonella Typhimurium, E. coli O157:H7, and L. monocytogenes by 6.23 and 5.57 log, 4.77 and 6.29 log, and 3.86 and 4.21 log after 3 and 5 min of exposure, respectively. Treatment D (15,000 ppm of Emery 658 and 15,000 ppm of lactic acid) reduced Salmonella Typhimurium by >6.90 log regardless of exposure time and E. coli )157:H7 and L. monocytogenes by 4.60 and >5.18 log and 3.55 and 3.14 log after 3 and 5 min, respectively. No significant differences (P > 0.05) were found between treatments A, C, and D. Overall, treatment D, which contained Emery 658 and lactic acid as active ingredients, reduced E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes populations by 3.55 to >6.90 log and may provide a viable alternative to the recommended 20,000 ppm of chlorine for sanitizing alfalfa seeds.

Colony Count, Microbial↗
PubMed2000

[Molecular identification of intergeneric somatic hybrid plants between alfalfa and sainfoin].

Somatic hybrid plants between alfalfa and sainfoin were regenerated by protoplast fusion and culture. DNA samples of the hybrid plants, hydroxyproline-resistant sainfoin plants, alfalfa cell line transformed with Agrobacterium tumefaciens 702 were isolated with a new and simple method. The hybridity was identified by random amplified polymorphic DNAs and Southern hybridization. Significant differences can be seen in the sequences amplified, which are specific for each parent/primer combination under the amplification conditions used. In 20 random oligonucleotide primers used, six could amplified more DNA fragments and had better polymorphisms. The results suggested that besides containing nuclear substances of two parents, the hybrid genome was inclined to eliminate sainfoin chromosome with DNA reconstruction. However, the somatic genome also could produce the sainfoin-specified DNA fragments which further confirmed by Southern hybridization. The hybrids were asymmetric and had certain regeneration ability just because the intervention of sainfoin DNA.

Blotting, Southern↗
PubMed2002

Variation in Ruminant Preference for Alfalfa Hays Cut at Sunup and Sundown.

Diurnal variation in the concentration of total nonstructural carbohydrates (TNC) occurs in plants as a result of photosynthesis. Ruminants have been shown to prefer tall fescue (Festuca arundinacea Schreber) hays cut in the afternoon but the effect of morning vs. evening cutting had not been tested in legumes. To test for diurnal variation in preference for alfalfa (Medicago sativa L.), we harvested six times in the midbud stage. Harvests were paired so that each time a cutting of alfalfa was made at sundown (PM) another was made the next morning at sunup (AM). We harvested in this manner three times resulting in six hays. The hays were field dried, baled, and chopped prior to their use 3 to 6 mo after harvest. Three experiments were conducted [Exp. 1, sheep (Ovis aries); Exp. 2, goats (Capra hircus hircus); and Exp. 3, cattle (Bos taurus)] utilizing six animals in each case. During an adaptation phase, hays were offered alone as meals. In the experimental phase, every possible pair of hays (15 pairs) was presented for a meal. Data were analyzed by multidimensional scaling as well as by traditional analyses. Multidimensional scaling indicated that the animals were basing selection on at least two criteria. Variables associated with preference through multiple regression varied across experiments but significant coefficients were found between preference and nitrate, protein, carbohydrate fractions, lignin, and cellulose. Coefficients varied depending on which other variables were in the model; however, carbohydrates were associated with positive coefficients. Shifting hay mowing from early in the day to late in the day was effective in increasing forage preference as expressed by short-term dry matter intake.

Journal Article↗
PubMedDate not supplied

Comparison of assurance gold salmonella EIA, BAX for screening/Salmonella, and GENE-TRAK Salmonella DLP rapid assays for detection of Salmonella in alfalfa sprouts and sprout irrigation water.

The Assurance Gold Salmonella EIA, BAX for Screening/Salmonella, and GENE-TRAK Salmonella DLP rapid assays were compared with official cultural methods described in the Bacteriological Analytical Manual (BAM) for analysis of alfalfa sprouts and sprout irrigation water for the presence of Salmonella. The lower limits of detection of 4 serovars of Salmonella cells (S. tennessee, S. muenchen, S. mbandanka, and S. cubana) in pure culture were determined as approximately log10 2, 5, and 6 for the BAX, GENE-TRAK, and Gold EIA, respectively. Despite its low detection limit, the BAX did not perform as well as the other assays in analyzing contaminated sprouts and sprout irrigation water. For 4 different lots of sprouts and sprout irrigation water samples inoculated with the 4 serovars at low [1-2 colony forming units (CFU/g)] and high (68-180 CFU/g) levels, the BAX detected Salmonella in 58/64 (90.6%) of the samples, compared with 64/64 (100%) by the GENE-TRAK, Gold EIA, and BAM methods. Assay performance was also compared for analysis of naturally contaminated sprouts and sprout irrigation water with 3 lots of alfalfa sprouted seeds associated with different salmonellosis outbreaks. Positive assay results for the naturally contaminated samples were Gold EIA 41, GENE-TRAK 36, BAM 33, and BAX 13.

Bacteriological Techniques↗
PubMed2002

Pyramiding Mn-superoxide dismutase transgenes to improve persistence and biomass production in alfalfa.

Expression of individual superoxide dismutase (SOD) transgenes improves environmental stress tolerance and biomass production in alfalfa (Medicago sativa L.). The objective of this study was to test the hypothesis that synergy exists between transgenic SOD stress-tolerance mechanisms, specifically that the simultaneous expression of two SOD transgenes confers greater benefit than the expression of a single SOD transgene. The hypothesis was tested through an evaluation of an F(1) family generated through a sexual cross of a hemizygous Mit-MnSOD plant and a hemizygous Chl-MnSOD-transgenic alfalfa plant which had previously been screened in field trials for improved persistence. Southern analyses revealed that the parents each had single insertion regions of the MnSOD cDNA and the inheritance followed the expected Mendelian ratios. Native PAGE gels and enzyme inhibition assays revealed the activity of the transgenic MnSOD isozymes. F(1) progeny containing either the Mit-MnSOD or the Chl-MnSOD transgene had significantly higher storage organ (crown+root) biomass compared to non-transgenic siblings. The joint expression of the transgenes resulted in a numerical increase in total SOD activity. However, F(1) progeny containing both transgenes had lower shoot and storage organ biomass compared to siblings having only one or the other transgene, a result that did not support the authors' hypothesis. It was postulated that a promoter with lower expression than 35S may be necessary if closely related transgenes are to be pyramided in the same plant.

Biomass↗
PubMed2002

[Response of alfalfa seed to stress storage conditions].

The seed germination rate, seed mortality, seedling length, and infection rate of alfalfa (Medicago sativa L. cv. 'Longdong') were measured at constant temperature 20 degrees C every 60 days during one year storage period after inoculated or no inoculated by Fusarium avenaceum under room temperature (RT), 35 degrees C, and 35 degrees C and +10% seed moisture content (SMC) conditions. Field emergence rates of seeds under above treatments were also observed, and seed-borne fungi were detected under the conditions mentioned above and controlled deterioration (CD) as well. The results showed that the percentage of isolated alfalfa seed-borne fungi was increased from 10% under room temperature and 35 degrees C to 29% under 35 degrees C + 10% SMC. Disease resistance was declined, and seed mortality and seedling infection rate under 35 degrees C + 10% SMC were significantly higher than those under room temperature and 35 degrees C respectively (P < 0.05). The seed germination rate and field emergence rate were also decreased significantly (P < 0.05). Seedling shoot and root length under 35 degrees C + 10% SMC were significantly less than those under RT and 35 degrees C respectively (P < 0.05). The percentages of both seed-borne fungi isolated and field emergence were decreased, and that of seedling infection was increased with storage period extending from 60 to 360 days. Compared to no inoculated control, the percentage of seed germination, seedling shoot and root length were decreased, and seed mortality and seedling infection rate were increased after inoculated by F. avenaceum.

Germination↗
PubMed2002

[Temporal pattern of arthropod community on cultivated alfalfa grassland].

The variation of species and diversities of the arthropod community on cultivated alfalfa grassland was investigated and studied. Principal component analysis and optimal sorting method were used to study its temporal patterns. The results showed that the difference and regularity of species richness, and the diversity and evenness of the arthropod community at different time were obvious. The numbers of the species of insect pests and their natural enemies were the most in the last ten days of June, but the peak period of individual numbers of the natural enemies was later than that of insect pests. The main factors and temporal patterns of arthropod community in the course of seasons were obvious. Based on the results, the temporal patterns of arthropod community on cultivated alfalfa grassland could be divided into four stages: before the first ten days of May, the middle ten days of May to the first ten days of June, the middle ten days of June to the middle ten days of July, and after the middle ten days of July. Considering the climatic and phenological development, the characteristics of the pests and the natural enemies occurring in each stage were analyzed, and the corresponding management tactics were discussed.

Animals↗
PubMedDate not supplied

[Growth and polysaccharide formation in Sinorhizobium meliloti strains in an air-lift-type fermentor. Effect on nodulation velocity in alfalfa plants].

In this paper the influence of the exopolysaccharides produced by Sinorhizobium meliloti strains on the nodulation rates in alfalfa plants has been considered. The experiments were performed in a rotary shaker and in an air-lift type fermentor. Different Sinorhizobium meliloti strains were used. Bacterial growth rates were determined by viable cell counts. Exopolysaccharide concentration was determined by precipitation with ethanol. It was observed that maximum cell concentration was in the order of 1 x 10(10) cell/ml and exopolysaccharide content was approximately 11 g/l. The experiments performed with alfalfa plants in a controlled environment chamber showed that, when inoculation was carried out with diluted suspensions (1/10), nodulation time was reduced from 10 to 4 days, while the strains retained their symbiotic properties.

Aerobiosis↗
PubMed1992

Effect of bulk feeds (alfalfa hay, corn silage) on the metabolism and liver parameters of growing geese.

Rearing experiments were conducted with a total of 90 liver hybrid geese from Babat, divided into three groups of 30 birds each. The effect exerted by all-concentrate feeding (group 1), concentrate feeding supplemented with alfalfa hay (group 2) or with corn silage (group 3) ad libitum on the blood glucose level, blood plasma total lipid, total cholesterol and free fatty acid level, and on total lipid content of the liver was studied. In addition, aspartate aminotransferase (AST) activity of the blood plasma and carotene, vitamin A and vitamin E concentration of the blood plasma and the liver were determined. It was found that the blood and liver parameters of goose groups fed different diets changed within the physiological limits typical of the species. Excessive fibre intake resulted in reduced lipid transport within the organism at an unchanged plasma cholesterol level; at the same time, blood glucose level remained unchanged. Ad libitum feeding of alfalfa hay and corn silage enhanced carotene and vitamin A transport and carotene storage but did not affect the transport of vitamin E. The results confirm earlier data of the literature that beta-carotene and vitamin A together impair vitamin E metabolism.

Animal Feed↗
PubMed1992

Characterization of a gene family encoding abscisic acid- and environmental stress-inducible proteins of alfalfa.

The phytohormone abscisic acid (ABA) has been proposed as a common mediator controlling adaptive plant responses to a variety of environmental stresses, including water deficit, salinity, wounding, and low temperature. We have recently isolated three cDNAs, pUM90-1, pUM90-2, and pUM91-4, from a cDNA library of ABA-induced mRNAs of alfalfa. These cDNA clones exhibit a very high degree of sequence homology with one another and sequence similarities with certain regions of several stress- and ABA-inducible genes. The polypeptides encoded by these cDNAs are very rich in glycine (35-40%), histidine (7-15%), asparagine (8-14%), and tyrosine (5-10%) and have no tryptophan and proline. All of the encoded polypeptides contain characteristic tandem repeats comprising glycine residues intercepted with histidine and/or tyrosine. The RNAs corresponding to a representative cDNA, pUM90-1, were induced after treatment of seedlings with low temperature, drought, salt, and wounding stress, but not by heat; the induction was maximal under low temperature treatment. ABA and ABA analog rapidly induced the expression of these genes, whereas gibberellic acid treatment exhibited no induction whatsoever. These genes appear to be specifically induced in the shoot tissues. Analysis of ABA induction of genes corresponding to pUM90-1 in alfalfa seedlings of different age groups demonstrated that these genes were inducible in seedlings/plants of all age groups examined. Taken together these results suggest that these cDNA clones encode a group of proteins that are inducible by ABA and multiple environmental stresses and correspond to a new family of genes of plants, designated as ABA- and environmental stress-inducible genes.

Abscisic Acid↗
PubMedDate not supplied

[Efficiency of alfalfa and reed in the phytoremediation of hydrocarbon polluted soil].

The efficacy of plants as means of decontaminating hydrocarbon-polluted soil has been studied. Ditch reed (Phragmites australis) and alfalfa (Medicago sativa) markedly intensified processes of pollutant destruction, the effect being particularly pronounced in the case of polycyclic aromatic hydrocarbons (PAHs). Comparative analysis of microflora in soils (including those devoid of plants and rhizosphere) demonstrated that, in addition to preventing the pollutant-induced decrease in the amount of heterotrophic microorganisms, the plants stimulated their development, significantly increasing the population of destructors. Effects of plants on major physiological groups of soil microorganisms under conditions of pollution were ambiguous. The rhizosphere consortium of alfalfa was less susceptible to effects of pollutants than that of reed.

Biodegradation, Environmental↗
PubMed2004

[Yield characteristics and genetic diversity of main alfalfa varieties in China].

The dry matter (DM) yield and its characteristics of 28 alfalfa varieties were evaluated in the 4th year under space sowing condition. The results showed that there existed significant difference (P<0.01) in DM yield and its characteristics among the varieties. The highest and higher DM yield were obtained form varieties Xinjiang Deye (452.8 g x plant(-1)) and Gannong No. 3 (373.0 g x plant(-1)), respectively, and the varieties with the highest height and branch/plant at the 3rd cutting were Gannong No. 3, Xinjiang Deye, Weixian, Tumu No. 2, Xinmu No. 1, and Zhaodong. The correlation analysis between DM yield and its characteristics indicated that the main factors affecting yield were the height and the branch/plant. The genetic diversity of DM yield and its components in 28 alfalfa varieties showed that the variations of DM yield and yield components of within-variety were larger than those of among-variety in majority of test varieties. The CV of all characteristics were presented in order of 3rd No. branch/plant>DM yield/plant>1st No. branch/plant>2nd No. branch/plant>Spring height>3rd height>2nd height>leaf width>budding height>leaf length>1st height.

Biomass↗
PubMed2005

[Genetic diversity analysis of alfalfa floral properties.].

Genetic mutations of alfalfa floral properties,including calyx diameter, coronary length, flower number per raceme, raceme number per twig, flower number per unit area, percentage of flicked flowers, excreted nectar volume, sugar concentration in nectar and contents of sucrose, fructose and glucose in nectar,have been studied with both morphological markers and RAPD markers. The results showed that the genetic variation of floral properties is from 0.80% to 92.30%, of which the content of glucose was the most significant one with the variation from 0.01 to 0.53 mumol/L (p0.05), and the sugar concentration was the most insignificant one (P>0.05). RAPD analysis showed that variances of genetic distances was from 0.21 to 0.35, among which the most significant one was WL323 and Shanbei, and the most insignificant one was Derby and Prime. Thus it can be seen that genetic diversity of floral properties among these varieties of alfalfas is abundant.

Carbohydrates↗
PubMed1991

Structural determination of bacterial nodulation factors involved in the Rhizobium meliloti-alfalfa symbiosis.

Extracellular signals produced by Rhizobium meliloti are able to induce root hair deformations and nodule organogenesis on alfalfa. The production of these signals is controlled by bacterial nod genes. To enable their isolation in significant amounts, an overproducting strain was constructed. These Nod factors were first extracted by butanol from the culture medium and further purified by reverse-phase high performance liquid chromatography, ion-exchange, and Sephadex LH-20 chromatographies. The structure of the major signal, called NodRm-1, was determined by mass spectrometry, nuclear magnetic resonance, 35S labeling, chemical analysis, and enzymatic degradation, and was shown to be a sulfated and acylated tetramer of glucosamine namely, beta-D-GlcpN(2,9-hexadecadie-noyl) - (1----4) - beta - D - Glc p Nac - (1----4) - beta - D - Glc p NAc - (1----4) - D - GlcpNAc-6-SO3H. Another Nod factor (called Ac-NodRm-1) was co-purified and identified as NodRm-1 acetylated on the C-6 of the nonreducing end sugar. NodRm-1 elicits root hair deformation specifically on alfalfa at a concentration less than 10(-10) M but has no effect on vetch (a heterologous host plant).

Acetylation↗
PubMed1990

Sequence analysis of acetylation and methylation in two histone H3 variants of alfalfa.

Analysis of acetylation in the two histone H3 variants of alfalfa by acid/urea/Triton-polyacrylamide gel electrophoresis has established that the minor variant H3.2 has a 2-fold higher level of acetylation than the major variant H3.1. Purification and sequence analysis of both variants showed sequence identity across the complete amino-terminal domain, which contains the 6 modified lysines 4, 8, 14, 18, 23, and 27. The two proteins have different distributions for acetylation: mono-, di-, and tri-methylation. The higher level of acetylation of H3.2 was confirmed in a wider pattern across all 6 lysines. Lysine modification levels varied for all sites in both proteins between 5 and 95%, with combinations of one to four types of modification co-existing at each residue. Additional sequence analysis of the H3.1 and H3.2 proteins and of tryptic core peptides established that the two histones differ only in residues 31, 41, 87, and 90. This indicates that major histone H3.1 is the product of the major alfalfa histone H3 gene and makes it likely that H3.2 is the product of the minor H3 gene, known from a partial cDNA clone. The variant-specific differences in lysine modifications in protein domains with identical primary structures suggest that the pattern and level of lysine modifications may be directed by the distinct chromatin environments of the two histone H3 variants.

Acetylation↗
PubMed1986

Hepatic enzyme changes in bovine hepatogenous photosensitivity caused by water-damaged alfalfa hay.

In the winter of 1983, practitioners reported extensive photosensitization in 7 herds of cattle. All herds had a history of having been fed water-damaged alfalfa hay. A cow from one herd was referred to the veterinary teaching hospital at Oklahoma State University. In this herd of approximately 40 adult Polled Herefords, all cattle had had some degree of clinical involvement over the past 4 to 6 weeks. Clinical signs included scaling and erythema of sparsely haired skin, muzzle, and teats, as well as icterus, anorexia, and weight loss. One cow died, and the remaining cattle recovered over an 8- to 10-week period after removal of the hay from the ration. In the referred cow, values for total and conjugated bilirubin, BUN, creatinine, sorbitol dehydrogenase, serum alkaline phosphatase, serum aspartate transaminase, and serum gamma-glutamyl transferase were higher than normal. In the herd of origin, extremely high serum gamma-glutamyl transferase values (180 to 1,400 IU/L) persisted (normal, 2 to 35 IU/L). Feeding the same alfalfa hay to 2 clinically normal cows reproduced the syndrome. The characteristic hepatic lesion was bile duct necrosis, with secondary bile duct hyperplasia.

Alkaline Phosphatase↗