Oak Leaf Research Articles

Reuse of Organomineral Substrate Waste from Hydroponic Systems as Fertilizer in Open-Field Production Increases Yields, Flavonoid Glycosides, and Caffeic Acid Derivatives of Red Oak Leaf Lettuce (Lactuca sativa L.) Much More than Synthetic Fertilizer.

Effects of organic waste from a hydroponic system added with minerals (organomineral fertilizer) and synthetic fertilizer on major polyphenols of red oak leaf lettuce using HPLC-DAD-ESI-MS(3) were investigated. Interestingly, contents of the main flavonoid glycosides and caffeic acid derivatives of lettuce treated with organomineral fertilizer were equal to those synthesized without soil additives. This was found although soil nutrient concentrations, including that of nitrogen, were much lower without additives. However, lettuce treated with synthetic fertilizer showed a significant decrease in contents of caffeic acid derivatives and flavonoid glycosides up to 78.3 and 54.2%, respectively. It is assumed that a negative effect of a high yield on polyphenols as described in the growth-differentiation balance hypothesis can be counteracted by (i) a higher concentration of Mg or (ii) optimal physical properties of the soil structure. Finally, the organomineral substrate waste reused as fertilizer and soil improver resulted in the highest yield (+78.7%), a total fertilizer saving of 322 kg ha(-1) and waste reduction in greenhouses.

Diversity of formyltetrahydrofolate synthetase genes in the rumens of roe deer (Capreolus pygargus) and sika deer (Cervus nippon) fed different diets.

Reductive acetogenesis by homoacetogens represents an alternative pathway to methanogenesis to remove metabolic hydrogen during rumen fermentation. In this study, we investigated the occurrence of homoacetogen in the rumens of pasture-fed roe deer (Capreolus pygargus) and sika deer (Cervus nippon) fed either oak-leaf-based (tannin-rich, 100 mg/kg dried matter), corn-stover-based, or corn-silage-based diets, by using formyltetrahydrofolate synthetase (FTHFS) gene sequences as a marker. The diversity and richness of FTHFS sequences was lowest in animals fed oak leaf, indicating that tannin-containing plants may affect rumen homoacetogen diversity. FTHFS amino acid sequences in the rumen of roe deer significantly differed from those of sika deer. The phylogenetic analyses showed that 44.8% of sequences in pasture-fed roe deer, and 72.1%, 81.1%, and 37.5% of sequences in sika deer fed oak-leaf-, corn-stover-, and corn-silage-based diets, respectively, may represent novel bacteria that have not yet been cultured. These results demonstrate that the rumens of roe deer and sika deer harbor potentially novel homoacetogens and that diet may influence homoacetogen community structure.

A systematic forest survey showing an association of Saccharomyces paradoxus with oak leaf litter.

Although we understand the genetics of the laboratory model yeast Saccharomyces cerevisiae very well, we know little about the natural ecology and environment that shaped its genome. Most isolates of Saccharomyces paradoxus, the wild relative of S. cerevisiae, come from oak trees, but it is not known whether this is because oak is their primary habitat. We surveyed leaf litter in a forest in Northern Germany and found a strong correlation between isolation success of wild Saccharomyces and the proximity of the nearest oak. We compared the four most common tree genera and found Saccharomyces most frequently in oak litter. Interestingly, we show that Saccharomyces is much more abundant in oak leaf litter than on oak bark, suggesting that it grows in litter or soil rather than on the surfaces of oaks themselves. The distribution and abundance of Saccharomyces over the course of a year shows that oak leaf litter provides a stable habitat for the yeast, although there was significant tree-to-tree variation. Taken together, our results suggest that leaf litter rather than tree surfaces provide the better habitat for wild Saccharomyces, with oak being the preferred tree genus. 99.5% of all strains (633/636) isolated were S. paradoxus.

Removal of Ni(II) and Cu(II) from aqueous solutions using 'green' zero-valent iron nanoparticles produced by oak and mulberry leaf extracts.

The production of zero-valent iron nanoparticles, using extracts from natural products, represents a green and environmentally friendly method. Synthesis of 'green' zero-valent nanoparticles (nZVI) using oak and mulberry leaf extracts (OL-nZVI and ML-nZVI) proved to be a promising approach for Ni(II) and Cu(II) removal from aqueous solutions. Characterization of the produced green nZVI materials had been conducted previously and confirmed the formation of nanosize zero-valent iron particles within the size range of 10-30 nm, spherical with minimum agglomeration observed by transmission electron microscopy and scanning electron microscope morphology measurements. Batch experiments revealed that the adsorption kinetics followed a pseudo-second-order rate equation. The obtained adsorption isotherm data could be well described by the Freundlich model and OL-nZVI showed higher adsorption capacity for Ni(II) removal than ML-nZVI, while ML-nZVI adsorption capacity was higher for Cu(II). In addition, investigation of the pH effect showed that varying the initial pH value had a great effect on Ni(II) and Cu(II) removal. Adsorbed amounts of Ni(II) and Cu(II) increased with pH increase to pH 7.0 and 8.0. This study indicated that nZVI produced by a low-cost and non-toxic method with oak and mulberry leaf extracts could be used as a new material for remediation of water matrices contaminated with Ni(II) and Cu(II).

Measuring microbial fitness in a field reciprocal transplant experiment.

Microbial fitness is easy to measure in the laboratory, but difficult to measure in the field. Laboratory fitness assays make use of controlled conditions and genetically modified organisms, neither of which are available in the field. Among other applications, fitness assays can help researchers detect adaptation to different habitats or locations. We designed a competitive fitness assay to detect adaptation of Saccharomyces paradoxus isolates to the habitat they were isolated from (oak or larch leaf litter). The assay accurately measures relative fitness by tracking genotype frequency changes in the field using digital droplet PCR (DDPCR). We expected locally adapted S.paradoxus strains to increase in frequency over time when growing on the leaf litter type from which they were isolated. The DDPCR assay successfully detected fitness differences among S.paradoxus strains, but did not find a tendency for strains to be adapted to the habitat they were isolated from. Instead, we found that the natural alleles of the hexose transport gene we used to distinguish S.paradoxus strains had significant effects on fitness. The origin of a strain also affected its fitness: strains isolated from oak litter were generally fitter than strains from larch litter. Our results suggest that dispersal limitation and genetic drift shape S.paradoxus populations in the forest more than local selection does, although further research is needed to confirm this. Tracking genotype frequency changes using DDPCR is a practical and accurate microbial fitness assay for natural environments.

Assessment of Sessile Oak (Quercus petraea L.) Leaf as Bioindicator for Exploration Geochemistry

The element contents of sessile oak (Quercus petraea L.) leaves which grow on hydrothermally altered area with high element contents were studied at Gumu‡hane and its near vicinity. The aim of this study is to determine threshold element contents of Q. petraea L. leaves growing on the area. For this purpose, oak leave samples collected were analyzed by inductively coupled plasma-mass spectrometry for concentrations of some elements which were the group of most common trace elements in exploration geochemistry studies. The assessment of the element contents of the oak leaf is based on the descriptive statistics and computations of threshold values of leaves depending on statistical parameters and average element contents of the plants growing on lands in normal background values for the elements. According to Q‐Q (normal quantile‐quantile) plots, the Kolmogorov‐Smirnov tests etc., all the elements, do not pass normality tests. Because of that, threshold values of the elements in leaves of oak were computed by median+median absolute deviation (MAD) and median+2MAD used in raw values for the elements. The data revealed that concentration levels of the examined elements in the leaves in the study area were determined as above and/or exceeded the upper limit of the normal range than in leaf of oak (Q. petraea L.) which grows on lands with normal elements background. Therefore, it is concluded that leaves of Q. petraea L. can be used as bioindicator in exploration geochemistry, especially for base metal ore deposits.

Structural and functional measures of leaf-associated invertebrates and fungi as predictors of stream eutrophication

Eutrophication is a major threat to freshwater ecosystems worldwide that affects aquatic biota and compromises ecosystem functioning. In this study, we assessed the potential use of leaf decomposition and associated decomposer communities to predict stream eutrophication. Because leaf quality is expected to affect leaf decomposition, we used five leaf species, differing in their initial nitrogen concentration. Leaves of alder, chestnut, plane, oak and eucalyptus were placed in coarse-mesh bags and immersed in six streams along an eutrophication gradient to assess leaf decomposition and the structure of associated decomposer communities. A hump-shaped relationship was established between leaf decomposition and the eutrophication gradient for all leaf species, except for eucalyptus. Invertebrate biomass and density as well as fungal biomass and sporulation were lowest at the extremes of the gradient. Leaf-associated invertebrate and fungal assemblages were mainly structured by stream eutrophication. The percentage of shredders on leaves decreased, whereas the percentage of oligochaeta increased along the eutrophication gradient. The Iberian Biological Monitoring Working Party Index (IBMWP) applied to benthic invertebrates increased from oligotrophic to moderately eutrophic streams and then dropped sharply at highly and hypertrophic streams. Overall, leaf decomposition was a valuable tool to assess changes in stream water quality, and it allowed the discrimination of sites classified by the IBMWP within class I and class IV. Moreover, decomposition of most leaf species responded in a similar way to eutrophication when decomposition was normalized by the quality of leaves.

Does the geography of cork oak origin influence budburst and leaf pest damage?

Spring shoot phenology is an adaptive trait highly responsive to climatic conditions that influences plant growth and development, as well as plant–herbivore interactions. We investigated if the geographic origin of cork oak influenced spring shoot phenology (timing of budburst) and if the variation among provenances (advances and/or delays) had consequences for leaf pest damage. The study was conducted in two provenance trials (planted in 1998) located in central and southern Portugal; each trial was surveyed during a two-year period. The variation in budburst timing was compared for 35 cork oak (Quercus suber L.) provenances sampled from the entire natural distribution of the species. Budburst exhibited high broad-sense heritability (0.79–0.94). Two East/West groups effectively separated Q. suber genetic structure and the timing of budburst. Provenances from the western part of the natural range tended to burst later than provenances from the eastern part. Budburst provenance ranking was similar between sites and years. Climate strongly influenced budburst date: in the year with warmer winter months (2004), all provenances in both sites exhibited earlier budburst in comparison with 2003 and 2005. Leaf pest damage was assessed at the southern provenance trial. Differences in the timing of budburst had a significant effect on insect activity (herbivory), which was more concentrated in time and thus more important in the year with later budburst. However, North African provenances with earlier budburst were more exposed to insect herbivory within each year. This study demonstrated a significant provenance effect on budburst timing of Q. suber that is partly genetically determined and has consequences for exposure to herbivory. Knowledge of cork oak locally adapted provenances is important for sustainable forest management in Mediterranean climate conditions, particularly for (re)forestation actions, because it favors higher survival and growth.

Características Produtivas de Cultivares de Alface Mimosa, Conduzida sob Diferentes Níveis de Sombreamento, no Inverno

This study aimed to evaluate the performance of mimosa lettuce, grown in a greenhouse with different levels of shading, under weather conditions of winter, in the region of Parana State, Brazil. The experiment was conducted at the Experimental Station of UNIOESTE, Campus Mal. Cândido Rondon in the period July to September 2010, in a randomized block design in a factorial 4x3, with four replications. The treatments consisted of four cultivars of lettuce (leaf green pixie Oak, Oak leaf red pixie, Salad Bowl and Roxane) and three shading levels 0, 30% and 50% shade). The lettuce cultivars were evaluated for plant height and diameter, head fresh weight, number of leaves per plant and also estimated the productivity. Growing lettuce mimosa under withouth shade in winter was most useful when compared with shading levels of 30% and 50%. Cultivar Roxane was more productive for this growing season.

Características produtivas de cultivares de alface mimosa, conduzida sob diferentes níveis de sombreamento, no inverno

This study aimed to evaluate the performance of mimosa lettuce, grown in a greenhouse with different levels of shading, under weather conditions of winter, in the region of Parana State, Brazil. The experiment was conducted at the Experimental Station of UNIOESTE, Campus Mal. Cândido Rondon in the period July to September 2010, in a randomized block design in a factorial 4x3, with four replications. The treatments consisted of four cultivars of lettuce (leaf green pixie Oak, Oak leaf red pixie, Salad Bowl and Roxane) and three shading levels 0, 30% and 50% shade). The lettuce cultivars were evaluated for plant height and diameter, head fresh weight, number of leaves per plant and also estimated the productivity. Growing lettuce mimosa under withouth shade in winter was most useful when compared with shading levels of 30% and 50%. Cultivar Roxane was more productive for this growing season.

Removal of As(III) and Cr(VI) from aqueous solutions using “green” zero-valent iron nanoparticles produced by oak, mulberry and cherry leaf extracts

The production of nano zero-valent iron nanoparticles, using the extract from natural products, increased in recent years as it represents green and environmentally friendly method. Synthesis of green zero-valent iron nanoparticles (nZVI) using oak, mulberry and cherry leaf extracts (OL-nZVI, ML-nZVI and CH-nZVI) proved to be a promising approach for As(III) and Cr(VI) removal from aqueous solutions. The oak, mulberry and cherry leaves were chosen because of their high oxidant capacity as an important property for the production of the nZVIs. Also, oak, mulberry and cherry trees are widely distributed and easy to find in Vojvodina, the north province of Serbia. Characterization of produced green nZVI materials confirmed the formation of nanosize zero-valent iron particles within the size of 10–30nm. Nanoparticles were spherical in shape and represented stable material with minimum agglomeration observed by TEM and SEM morphology measurements. Batch experiments revealed that the adsorption kinetics followed pseudo-second order rate equation. The obtained adsorption isotherm data could be well described by the Freundlich model. In addition, investigated pH effect showed that varying the initial pH value had a great effect on As(III) and Cr(VI) removal. This study indicated that nZVI could be produced by low cost and non toxic method with oak, mulberry and cherry leaf extracts and potentially be used as a new green material for remediation of water matrices contaminated with As(III) and Cr(VI).

Growth and nutritional properties of lettuce affected by mixed irradiation of white and supplemental light provided by light-emitting diode

‘Green Oak Leaf’ lettuce were hydroponically cultured for 35days under mixed light qualities of white light and a different supplemental light such as blue (B), green (G), yellow (Y), red (R), and far-red (Fr) provided by light-emitting diodes (LEDs). Effects of supplemental light qualities on the growth and nutritional properties of lettuce plants were investigated. The pure white LED (W) was used as control with a photosynthetic photon flux (PPF) value of approximately 135μmolm−2s−1, and the basal white light in each treatment was 105μmolm−2s−1 while the photon flux added by supplemental LED was approximately 30μmolm−2s−1. The results indicated that supplemental lights led to obvious morphological changes, plants with WR appeared compact and vigorous while those with WY and WFr looked sparse and twisted, dwarfed plants with large leaves were detected under WB. Compared with those grown in the white light control, the fresh weight of shoots increased by 63.2% and 21.7% with supplemental R and B respectively, while decreased by 35.9% with supplemental Fr. Chlorophyll and carotenoid contents were significantly higher with supplemental R and B than other treatments. Supplemental B and G resulted in decrease of nitrate content. Supplemental G significantly promoted soluble sugar accumulation. Supplemental Fr increased S/R ratio and ascorbic acid accumulation but resulted in lower biomass and pigment contents. However, no positive impact of supplemental Y light was observed in the research.

Effect of Supplementing Streptococcus gallolyticus Strain TDGB 406 on Rumen Fermentation and Microbial Profile of Goats Fed on Oak Leaves

An experiment was conducted to study the effect of supplementation of tannin degrading bacteria (Streptococcus gallolyticus strain TDGB 406) on rumen fermentation and microbial profile of goats fed on oak (Quercus semicarpifolia) leaves. Three adult male goats (average body weight 27.5±1.0 kg) fitted with permanent fistula were distributed into three groups (switch over design). The animals of group 1 served as control (C) while animals of group T1 and T2 were given autoclaved and live culture of isolate TDGB 406 (106 cells/ml), respectively @ 5 ml/kg live weight. The animals were fed measured quantity of dry oak leaves as the main roughage source and ad libitum maize hay along with fixed quantity of concentrate mixture. The feeding of live culture of isolate TDGB 406 as probiotic did not show any effect on the rumen fermentation pattern viz. pH, total nitrogen, TCA ppt-N, NPN, lactic acid, total volatile fatty acids production and the activities of carboxymethylcellulase, xylanase, protease and tannase. However, the production of NH3-N was higher (P<0.05) in live culture fed animals as compared to control group. The population of rumen protozoa, total bacteria and fungi were similar in all the three groups, whereas, tannin degrading bacteria population was higher in T2 where the live culture of TDGB 406 was fed. The results of the study indicated that TDGB 406 can modify rumen microbial eco-system when used as probiotic in goats without disturbing the rumen environment.

Effect of Vitamin C, Red Pepper and Oak Leaves on Physiological and Productive Performance of Quail

ABSTRACT: The current study was conducted on the animal production college of agriculture and forestry-University of Duhok, in order to investigate the effect of ration supplementation with vitamin C, red pepper (RP) and oak leaves (OL) on some physiological, reproductive and productive parameters of quail. Four hundred eighty quail birds (7 days) were divided into four groups with three replicates / group (40 birds/replicate, the groups were treated from the age of 7 days till the age of 49 days as follows: T1 (control): Reread on standard ration, T2: Reread on standard ration supplemented with vitamin C(300mg /kg ration). T3: Reread on standard ration supplemented with red pepper crush (5g/kg ration). T4: Reread on standard ration supplemented with oak leaves crush (10g/kg ration).The results of the current study revealed the following: Significant increase in live body weight (LBW) and body weight gain (BWG) of treatment as compared with control, significant decrease in feed consumption (FC) in vit. C group as compared with control, a significant improvement feed conversion ratio (FCR) in OL group as compared with control and in RP and vit. C groups as compared with OL group, a significant decrease in carcass weight of RP group as compared with control and OL groups and in heart relative weight as compared with vit. C group. Significant increase in mean egg weight, hen day (HD) % and egg mass/hen in OL group as compared with control and in as compared with other treatments. Significant increase in serum total protein (TP) and globulin in OL group as compared with vit. C group and a significant decrease in serum albumin in RP group as compared with control of male quail and a significant decrease in serum TP, globulin, albumin and TG in all groups as compared with control of female quail, a significant decrease in Cholesterol in OL group compared with control and in glucose as compared with RP and vit. C groups. Significant improvement in Lymphocyt (L)%, Heterophil (H)% and stress index in OL group of female quail and in L% and in H% in vit. C group of male quail significant improvement in yolk index in OL group and in shell membrane thickness in control group. Key words : Oak leaves, Quail, Production, Red pepper and Vitamin C

Large drought-induced variations in oak leaf volatile organic compound emissions during PINOT NOIR 2012

Leaf-level isoprene and monoterpene emissions were collected and analyzed from five of the most abundant oak (Quercus) species in Central Missouri's Ozarks Region in 2012 during PINOT NOIR (Particle Investigations at a Northern Ozarks Tower - NOx, Oxidants, Isoprene Research). June measurements, prior to the onset of severe drought, showed isoprene emission rates and leaf temperature responses similar to those previously reported in the literature and used in Biogenic Volatile Organic Compound (BVOC) emission models. During the peak of the drought in August, isoprene emission rates were substantially reduced, and response to temperature was dramatically altered, especially for the species in the red oak subgenus (Erythrobalanus). Quercus stellata (in the white oak subgenus Leucobalanus), on the other hand, increased its isoprene emission rate during August, and showed no decline at high temperatures during June or August, consistent with its high tolerance to drought and adaptation to xeric sites at the prairie-deciduous forest interface. Mid-late October measurements were conducted after soil moisture recharge, but were affected by senescence and cooler temperatures. Isoprene emission rates were considerably lower from all species compared to June and August data. The large differences between the oaks in response to drought emphasizes the need to consider BVOC emissions at the species level instead of just the whole canopy. Monoterpene emissions from Quercus rubra in limited data were highest among the oaks studied, while monoterpene emissions from the other oak species were 80-95% lower and less than assumed in current BVOC emission models. Major monoterpenes from Q. rubra (and in ambient air) were p-cymene, α-pinene, β-pinene, d-limonene, γ-terpinene, β-ocimene (predominantly1,3,7-trans-β-ocimene, but also 1,3,6-trans-β-ocimene), tricyclene, α-terpinene, sabinene, terpinolene, and myrcene. Results are discussed in the context of canopy flux studies conducted at the site during PINOT NOIR, which are described elsewhere. The leaf isoprene emissions before and during the drought were consistent with above canopy fluxes, while leaf and branch monoterpene emissions were an order of magnitude lower than the observed above canopy fluxes, implying that other sources may be contributing substantially to monoterpene fluxes at this site. This strongly demonstrates the need for further simultaneous canopy and enclosure BVOC emission studies.

Effects of various host plants on nutritional indices and some biochemical compounds in green oak leaf roller, Tortrix viridana L. (Lepidoptera: Tortricidae)

The green oak leaf roller, &lt;em&gt;Tortrix viridana&lt;/em&gt; L., is one of the most destructive pests, causing damages to various species of oak, feeding on different host plants including &lt;em&gt;Quercus infectoria&lt;/em&gt; Oliv, &lt;em&gt;Q. branti&lt;/em&gt; Lindl, and &lt;em&gt;Q. libani&lt;/em&gt; Oliv. Nutritional indices, activity of enzymatic and non-enzymatic compounds of &lt;em&gt;T. viridana&lt;/em&gt; were studied under laboratory conditions. In addition, chemical components were analysed in the leaves of the three host plants. Fourth instar larvae reared on &lt;em&gt;Q. branti &lt;/em&gt;showed the highest values of relative consumption rate (RCR), approximate digestibility, and consumption index (48.73±6.22; 90.45±1.06 and 97.45±12.44 respectively), while the lowest values were observed on &lt;em&gt;Q. libani&lt;/em&gt;. Efficiency of conversion of ingested food in the fourth instar larvae was the highest (3.17±0.661) on &lt;em&gt;Q. libani&lt;/em&gt; and the lowest (1.53±0.164) on &lt;em&gt;Q. branti&lt;/em&gt;. The fifth instar larvae fed on &lt;em&gt;Q. libani&lt;/em&gt; had the highest RCR (15.64±2.51). The highest amounts of triglycerides, uric acid, glucose, protein and the lowest activity of alkaline phosphatase were observed in the fifth instar larvae reared on &lt;em&gt;Q. libani&lt;/em&gt;. The leaves of Q. libani highlighted the highest amounts of total nitrogen, total protein, water, potassium, magnesium and total carbohydrate. The present research suggested that the nutritional quality of the host plants have crucial effects on &lt;em&gt;T. viridana&lt;/em&gt; larvae.

ANALYSIS OF THE BACTERIAL EPIPHYTIC MICROBIOTA OF OAK LEAF LETTUCE WITH 16S RIBOSOMAL RNA GENE ANALYSIS

The leaf microbiota has major influences on the quality of ready-to-eat lettuce. While studies investigating the epi- and endophytic microbiota of lettuce have been published, no protocols focusing only on the epiphytic microbiota exist. As the epiphytic microbiota may be especially influenced by technological steps in the production of ready-to-eat lettuce, an in-depth knowledge of these microorganisms is essential with regard to consumer safety and spoilage. Currently it is not clear to what extent results gained from single samples are representative of the community composition. A technique for the separation of bacterial cells from the leaf surface was applied to green oak leaf lettuce. The bacterial diversity was analysed in triplicate with high throughput Roche 454 sequencing of prokaryotic 16S rRNA genes to analyse the intra-sample variation. Sequence analysis revealed members of the phyla Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Gemmatimonadetes, Proteobacteria and Verrucomicrobia, and of the candidate division WYO. The ten most abundant proteobacterial genera in all three samples were Alkanindiges (24.6%), Pseudomonas (11.3%), Sphingomonas (8.6%), Janthinobacterium (8.3%), Acinetobacter (4.3%), Polaromonas (1.3%), Erwinia (1.1%), and Methylobacterium (1.1%). The genera Pedobacter (2.5%) and Hymenobacter (1.4%) dominated the phylum Bacteroidetes. The intra-sample variation was less than 0.7% for seven of these most abundant genera with the exception of Pseudomonas, Janthinobacterium and Alkanindiges, where larger standard deviations were obtained. This low intra-sample variation demonstrates that the established technique based on oak leaf lettuce is suitable for the culture-independent analysis of the epiphytic bacterial microbiota of produce.

Effect of rumen bacteria from sheep adapted to a tanninferous diet on in vitro fermentation parameters of pistachio hulls using bovine inoculum.

Sheep adapted to consume tannins rich feeds such as oak leaf (OL) appear to develop defensive mechanisms by their ruminal bacteria against these polyphenols. The capabilities of ruminal isolated tannins resistant bacteria from these animals to ferment a tanniniferous feed (i.e., pistachio hulls, (PH) which were incubated with rumen fluid from Holstein dairy cows was assessed. Six g positive cocci were isolated from the rumen of sheep and the 16s rRNA gene sequences showed them to be closely related to Streptococcus gallolyticus. In three runs of in vitro gas production (GP), the effect of two of the isolates incubated with buffered-ruminal fluid of Holstein cow and PH was evaluated. The GP was recorded from 1 to 96 h of incubation. Incubating either of the isolates with PH caused a significantly higher in vitro gas production, estimated parameters, in vitro organic matter disappearance, metabolisable energy and volatile fatty acids than those without any isolate. The improvement in the ruminal parameters when either of the isolates was used suggested the possible presence of isolated tannins-resistant bacteria (Streptococcus gallolyticus sp.), however, in vivo studies must be conducted to confirm the in vitro results.

Can Plant Breeding Go Open Source?

Can Plant Breeding Go Open Source?

Variation of the Pseudomonas community structure on oak leaf lettuce during storage detected by culture-dependent and -independent methods

The genus Pseudomonas plays an important role in the lettuce leaf microbiota and certain species can induce spoilage. The aim of this study was to investigate the occurrence and diversity of Pseudomonas spp. on oak leaf lettuce and to follow their community shift during a six day cold storage with culture-dependent and culture-independent methods. In total, 21 analysed partial Pseudomonas 16S rRNA gene sequences matched closely (> 98.3%) to the different reference strain sequences, which were distributed among 13 different phylogenetic groups or subgroups within the genus Pseudomonas. It could be shown that all detected Pseudomonas species belonged to the P. fluorescens lineage. In the culture-dependent analysis, 73% of the isolates at day 0 and 79% of the isolates at day 6 belonged to the P. fluorescens subgroup. The second most frequent group, with 12% of the isolates, was the P. koreensis subgroup. This subgroup was only detected at day 0. In the culture-independent analysis the P. fluorescens subgroup and P. extremaustralis could not be differentiated by RFLP. Both groups were most abundant and amounted to approximately 46% at day 0 and 79% at day 6. The phytopathogenic species P. salmonii, P. viridiflava and P. marginalis increased during storage. Both approaches identified the P. fluorescens group as the main phylogenetic group. The results of the present study suggest that pseudomonads found by plating methods indeed represent the most abundant part of the Pseudomonas community on oak leaf lettuce.