Stem Fractions Research Articles

Phytochemical Constituents in Hexane Fraction of Costus afer Ker Gawl. Stem

In view of the high demands for alternative medicines in developing countries and the dearth of valid scientific data on herbal formulations. This study was designed to identify and characterize the bioactive compounds present in hexane fraction of Costus afer ker Gawl stem, an indigenous medicinal African plant used as therapy in the treatment of chronic inflammatory disease such as rheumatoid arthritis. Phytochemical evaluation and gas chromatography-mass spectrometry (GC/MS) analytical methods were carried out. The mass spectra of the identified compounds were compared with those of the National Institute of Standards and Technology database library. Results showed the presence of alkaloids, diterpenes, triterpenes, phytosterol, phenol, phlobatannins and tannins while GC/MS data detected 16 compounds including benzofuran, 2,3-dihydro and oleic acid. These compounds identified in the hexane fractions of C. afer stem may explain the folkloric use of C. afer plant stem extract in the treatment of chronic inflammatory diseases.

Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2_Adj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha−1. While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased.

Вплив гіпертиреозу на процеси навчання та стан гліальних проміжних філаментів головного мозку щурів

The influence of hyperthyreosis on oxidative stress, state of glial intermediate filaments and memotry was investigated. Significant increasing of lipid peroxidation products into both hippocampus and cortex and change for the worse of memory was observed. Analysis of the behavioral reactions of rats in the test of passive avoidance conditioned reflex showed that the acquisition of skills of all groups of animals did not differ by time waiting period (latent period). Time saving memory test conditioned reflex of passive avoidance was excellent in the group of rats treated with thyroxine compared with controls. The change of polypeptide GFAP was observed in hippocampus and cortex. Both soluble and filamentous forms of GFAP increased in hippocampus of rat with hyperthyreosis. In filament fractions, increase in the intensity of 49 kDa polypeptide band was found. In the same fraction of insoluble cytoskeleton proteins degraded HFKB polypeptides with molecular weight in the region of 46–41 kDa appeared. Marked increase of degraded polypeptides was found in the soluble fraction of the brain stem. The intensity of the intact polypeptide (49 kDa), as well as in the filament fraction, significantly increased. It is possible that increasing concentrations of soluble subunits glial filaments may be due to dissociation of own filaments during the reorganization of cytoskeleton structures. Given the results of Western blotting for filament fraction, increased content of soluble intact 49 kDa polypeptide is primarily the result of increased expression of HFKB and only partly due to redistribution of existing filament structures. Calculation and analysis of indicators showed high correlation between the increase in content and peroxidation products of HFKB. These results indicate the important role of oxidative stress in the induction of astroglial reactive response under conditions of hyperthyroidism. This data shows the possibility of the glial cell cytoskeleton reconstruction under effect of thyroid hormones.

Methicillin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecalis and Enterococcus faecium active Dimeric Isobutyrylphloroglucinol from Ivesia gordonii

Bioassay-guided fractionation of the chloroform soluble fraction of stem, leaf, and flower extracts of the American plant Ivesia gordonii led to the isolation of a new dimeric acylphloroglucinol, 3,3'-diisobutyryl-2,6'-dimethoxy-4,6,2',4'-tetrahydroxy-5,5'dimethyldiphenyl methane (1), to which we have assigned the trivial name ofivesinol (1), together with a known monomeric acylphloroglucinol, 1,5-dihydroxy-2-(2'-methylpropionyl)-3-methoxy-6-methylbenzene (2). The structures of the isolated compounds were characterized using 1D- and 2D- NMR spectroscopy, including COSY, HMQC, HMBC, and ROESYexperiments, as well as mass spectrometry. Ivesinol (1) showed potent activity against Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) with IC50/MIC/MBC values of 0.10/1.25/>20 microg/mL and 0.05/0.31/>20 microg/mL, respectively (vs. IC50/MIC/MBC 0.13/0.5/1.0 microg/mL and 0.13/0.5/1.0 microg/mL of ciprofloxacin), while the corresponding monomer 2 was found to be less active. Compound 1 also demonstrated strong activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MlC/MBC values of 0.22/1.25/>20 microg/mL, whereas the reference standard ciprofloxacin was found to be inactive against this strain. In addition, compound 2 showed moderate activity against two species of Candida and Cryptococcus neoformans, while 1 was inactive against these fungi. In order to evaluate the influence of the acyl group(s) in phloroglucinol (3) as a ligand, the mono- (4) and diacetylphloroglucinol (5) were prepared from 3, and evaluated for their in vitro SA, MRSA, and VRE activities; 2,4-diacetylphloroglucinol (5) showed potent activity, like 1, against SA, MRSA, and VRE (ATCC 700221) with IC50/MIC values of 0.3/2.5, 0.23/2.5, and 0.86/2.5 microg/mL, respectively, while 4 was inactive.

Structural Characteristics of Mulato Grass I under Different Cutting Heights

This work aimed to evaluate the effects of different individual heights of cut on structural characteristics of Brachiaria hibrida cv. Mulato I in four periods of the year. The study was carried out at the Fazenda Experimental Vale do Acaraú, in Sobral, Ceará, Brazil, from January to December, 2008. The experimental design was a split plot, with the plots representing four pasture conditions through manual cuts of 10 cm, 20 cm, 30 cm and 40 cm heights, which were done every 30 days. Each treatment had three replications. The subplots were represented by four periods of evaluation: January-February-March, April-May-June, July-August-September and October-November-December. Fertilization was performed with 350 kg of N/ha, divided into monthly applications. Irrigation was conducted in alternate days during the dry season. The variables studied were: mean height before cutting (cm); dry matter content (%); total dry matter production (t/ha); percentage of leaves; percentage of stems; percentage of dead material; leaf blade/stem ratios; number of total leaves per tiller; number of live leaves per tiller; average size of leaves; and tiller density. Cutting at 10 cm caused a decrease in total dry matter production, underestimating the potential production. Cutting heights between 20 and 30 cm contributed positively to increase the total number of leaves, number of green leaves, average size of the leafs and total dry matter production. Under the present experimental conditions, cutting around 40 cm was not recommended because of a decreasing in the leaf/stem ratio and a increasing in stem fraction and dry matter content, compromising the structure of the canopy.

Ferric Reducing, Anti-radical and Cytotoxic Activities of Tinospora cordifolia Stem Extracts

Introduction: Tinospora cordifolia (Menispermaceae) is used as folk remedy against many diseases. This work reports the antioxidant and cytotoxic activities of T. cordifolia stem extracts. Materials and Methods: Dried samples were sequentially extracted in different solvents. Antioxidant activity was determined by using ferric reducing antioxidant power (FRAP), β-carotene bleaching and lipid peroxidation inhibition assays. Cytotoxicity against cancer cell lines was determined by SRB assay. Results: Chloroform, ethyl acetate, acetone, and ethyl alcohol extracts demonstrated higher FRAP values (4981-6568 µmol ferrous sulphate equivalent/mg). Aqueous, ethyl alcohol and chloroform extracts showed better β- carotene bleaching inhibition potential (zone of inhibition 15mm). Acetone and ethyl alcohol extracts accounted for moderate (48% and 53%, respectively) lipid peroxidation inhibition in rat liver homogenate. Aqueous fraction of stem exhibited potent cytotoxic activity (67-99%) against prostate, lung and colon cancer cell lines. Conclusion: The study showed that T. cordifolia stem has considerable potential as antioxidant and cytotoxic agents.

Proximate composition, mineral content and in vitro antioxidant activity of leaf and stem of Costus afer (Ginger lily).

Aim:This study was designed to determine the proximate composition and mineral content of Costus afer leaf and stem, as well as to identify the most active antioxidant fraction.Materials and Methods:The proximate composition and mineral analysis of C. afer leaf and stem were performed using the standard methods described by Pearson and Association of Official Analytical Chemist while the 1,1 diphenyl 2 picryl hydrazyl (DPPH), thiobarbituric acid reactive species (TBARS), lipid peroxidation (LPO), and total antioxidant capacity (TAC) assays were used to determine the in vitro antioxidant activity of aqueous, n-butanol, ethyl acetate and hexane fractions of C. afer leaf and stem.Results:Proximate analysis revealed that the carbohydrate content was highest in the leaf (55.83 ± 3.71%) and stem (50.38 ± 1.27%) while crude fat content was lowest in the leaf (1.83 ± 0.43%) and stem (1.75 ± 0.48%). The minerals detected in appreciable quantity in both the leaf and stem samples were calcium, magnesium, potassium, sodium, chromium, lead, manganese, nickel, and copper. Further study showed that the aqueous leaf fraction exhibited a significantly (P < 0.05) high DPPH scavenging activity (IC50 = 259.07 µg/ml) and TAC (7.95 ± 0.37 mg ascorbic acid equivalent/g) compared with the other test fractions while the aqueous stem fraction had the highest TBARS scavenging activity (IC50 = 0.37 µg/ml) and inhibition of LPO (IC50 = 41.15 µg/ml) compared with the other test fractions.Conclusion:The findings from this study indicate that C. afer could serve as a source of nutrient and minerals for animal nutrition and human metabolism. It also showed that the aqueous fractions of C. afer leaf and stem possess high antioxidant activity than the other fractions. In addition, this study may also explain the folkloric use of crude C. afer leaf or stem extracts in the treatment of oxidative stress associated diseases, including rheumatoid arthritis and hepatic disorder.

Effects of Submergence and Nitrogen Concentration on the Resources Utilization of &lt;i&gt;Alternanthera philoxeroides&lt;/i&gt;

This study examined the effects of submergence and nitrogen concentration on biomass allocation and nutrients utilization of an invasive plant Alternanthera philoxeroides. In the experiment, A. philoxeroides was applied to two water level treatments (0 and 25cm above the surface) across with two nitrogen concentrations (0 and 10 mg/l N). The results showed that submergence decreased leaf fraction and increased stem fraction, but high N changed this situation. In submergence, high N increased leaf fraction but decreased stem fraction due to leaves survival and maintenance. Submergence decreased root fraction and the content of soluble sugar in stem. The results suggested that high N concentration could counteract the negative effects of submergence. Therefore, the risk of A. philoxeroides invasion might be enhanced by nitrogen pollution in fluctuating water bodies, and should be attention intensely.

Inflammation Induces Hematopoietic Stem Cell/Progenitor Migration and Recruitment To Lymph Nodes In Mice and Humans

Under steady-state conditions a small fraction of hematopoietic stem and progenitor cells (HSPC) circulate in the bloodstream. Circulation of HSPC follows a circadian rhythm of migration from the bone marrow (BM) to blood and possibly, lymph. The functional purpose of circulating HSPC is unclear but it has been associated with homeostatic regulation of tissue-specific reservoir of HSPC, vasculogenesis and immunosurveillance. During infectious stress, HSPC are activated by inflammation mediators and chemokines and mobilized to circulation and extramedullary tissues. Side Population (SP) cells are stem cells with pluripotent differentiation ability found in a number of adult tissues. Here we have studied whether the lymph nodes (LN) are an obligatory site of transit/homing of HSPC in inflammation. To analyze whether there is accumulation of HSPC in inflammatory lymph nodes, we first analyzed the presence of SP cells in human LN. The patient median age was 34 (range 3-89). Patient-derived LN biopsies were diagnosed by the pathologist as having reactive lymphadenitis (RL, n=35, 50.7%) or cancer (n=34, 49.3.%). Cancer diagnoses were Hodgkin's Lymphoma (HL, n=12,17.4%), non-Hodgkin's lymphoma (NHL, n=20, 28.9%) or adenocarcinoma (AC, n=2, 2.9%) which associate with decreasing levels of inflammation. The biopsy-derived LN cells were stained with Hoechst 33342/propidium iodide and monoclonal antibodies against CD45, CD34, CD20, CD19, CD133 and ABCG2 surface markers. Flow cytometry analysis of LN specimens identified SP cells in 82.3% of RL LN samples (1.9±1.2%; range 0-39%), 50% of HL LN biopsies (0.7±0.6%; range 0-7.7%) and 20% of NHL LN biopsies (0,03±0.01%; range 0-0.23). Interestingly, SP cells were absent from AC LN specimens. The presence of LN SP cells was significantly associated with RL versus any of the analyzed cancer groups (P<0.001). The phenotype of human SP cells in all SP-positive LN specimens was CD45+/CD34-/CD19-/CD20-/CD133Low/neg. ABCG2 protein expression had a strong correlation with the presence of SP cell positive samples (c2=11.8, p=0.001). To identify whether inflammation was associated to HSPC migration to LN, we analyzed the SP cells and functional myeloid progenitor cell (CFU) content of different organs in adult mice treated with lipopolysaccharide (LPS, 3 mg/Kg) or vehicle control at 6 and 12 hours post-administration. LPS treatment resulted in migration of HSPC to LN (∼13-fold), liver (∼7-fold) and kidney (∼4 fold). Circulation of HSPC in peripheral blood increased (∼8 fold) but no HSPC was found in the thoracic duct or other organs after up to 12 hours post-infusion of LPS. These data suggest the co-existence of direct migration of HSPC to peripheral blood and lymphatic vessels. Migration of HSPC to the lymph is followed by efficient LN homing/retention of HSPC. In summary, we have found that inflammation associates with HSPC mobilization and recruitment to LN in mice and humans, strongly suggesting that local inflammatory signals are crucial in the regulation of the traffic and homing of HSPC. Disclosures:No relevant conflicts of interest to declare.

STUDY OF ANALGESIC AND ANTIDIARRHOEAL ACTIVITIES OF Sonneratia caseolaris (LINN.) LEAF AND STEM USING DIFFERENT SOLVENT SYSTEM.

The different fractions of crude ethanol extract of leaf and stem of S. caseolaris (Linn.) (Sonneratiaceae) were screened for its analgesic and antidiarrhoeal activities. The different fraction of crude extract was obtained by using four different solvent systems. The different fractions of crude extract produced significant writhing inhibition in acetic acid induced writhing in mice at dose of 250 and 500mg/kg BW comparable to the standard drug diclofenac sodium at the dose of 25mg/kg BW. When tested for its antidiarrhoeal effects on castor oil induced diarrhea in mice, it increased mean latent period and decreased the frequency of defecation significantly at the dose of 250 and 500mg/kg BW comparable to the standard drug loperamide at the dose of 50mg/kg BW. The overall results tend to suggest the analgesic and antidiarrhoeal activities of the different fractions of crude extract. Both ethyl acetate fraction of stem and chloroform fraction of leaf have significant analgesic activity. Again between the two fractions of crude ethanol extract ethyl acetate fraction of S.caseolaris stem have most significant antidiarrhoeal activity. Key words: analgesic, antidiarrhoeal, S.caseolaris, diclofenac sodium, loperamide.

English

The aim of the present study was to compare the phytochemical and radical scavenging activities in the stem and leaf fractions of two species in Amaranthaceae family Amaranthus tristis and Alternanthera sessilis. Total flavonoids and phenolics were estimated using aluminium chloride and Folin-Ciocalteau methods, respectively; radical scavenging activities of the extracts were determined by 2, 2-diphenyl-1-picryl hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assay. Our results showed that A. sessilis had higher levels of flavonoids (70.42 mg/100 g) and phenolics (103.75 mg/100 g), when compared with A. tristis that had relatively lower levels of flavonoids (62.87 mg/100 g) and phenolics (96.89 mg/100 g) in leaf fractions. The stem and leaf fractions of A. sessilis showed more DPPH and FRAP values indicating the higher radical scavenging activity of the extract, when compared to A. tristis. It was also found that the flavonoids and phenolics content are directly proportional to the radical scavenging activities of both vegetables. The results concluded that A. sessilis have relatively more phytochemicals and radical scavenging activities and it also reveals that the leaf fraction has more flavonoid and phenolic content than the stem fractions in both vegetables. It is clear that both plants have definitely more antioxidant properties making it an ideal dietary antioxidant supplement. Key words: Phytochemicals, antioxidants, total flavonoids, total phenolics, radical scavenging activity.

Assessment of leaf/stem ratio in wheat straw feedstock and impact on enzymatic conversion

AbstractThe composition of wheat straw leaf and stem fractions were characterized using traditional strong acid hydrolysis, and monoclonal antibodies using comprehensive microarray polymer profiling (CoMPP). These results are then related to high throughput lignocellulose pretreatment and saccharification screening data. Pure leaf fraction of wheat straw was the least recalcitrant compared to pure stem and easily digested by commercial cellulases after moderate hydrothermal pretreatment; 63% and 31% (w/w) of glucan, 88% and 61% of xylan were released from the leaf and stem fractions, respectively. By preparing samples of various leaf‐to‐stem (L/S) ratios, we found shifting conversion behavior as processing parameters were modified. Increasing the enzyme dosage, pretreatment temperature and pretreatment time all significantly improved conversion rates in samples with more than 50% leaf content, whereas less impact was observed on samples with less than 50% leaf content. Enzyme affinity, desorption and readsorption with leaf and stem fractions may affect the sugar yield in wheat straw saccharification. The data suggest that the L/S ratio is an important parameter when adjusting or optimizing conversion processes and additionally in feedstock breeding. Furthermore, this highlights the need for rapid techniques for determining L/S ratio in wheat straw harvests. The CoMPP data on specific carbohydrates and leaf pectin highlight carbohydrate epitopes that may be useful as markers in the development of novel screening techniques; especially pectin or arabinogalactan proteins related epitopes are promising.

Curva de desidratação e composição químico-bromatológica do feno de grama-estrela (Cynodon nlemfuensis Vanderyst) em função do teor de umidade no enfardamento

It was aimed at to determine the dehydration curve and the moisture content effect during the baling process in the chemical composition of star grass ( Cynodon nlemfuensis Vanderyst) hay. Samples were collected from harvest until baling to determine the dehydration curve of both whole plant and leaf and stem fractions. The baling process occurred with predetermined moisture contents: 25, 16 and 12%. A completely randomized experimental design with ten replications was used, and the chemical bromatological composition data were compared by Tukey Test (5%). The water loss rate was higher for leaf when compared to stem fraction. In the early hours after storage, it was noticed higher heat for hays with 25% of moisture content. There was not effect of moisture content during baling process in the chemical composition of star grass hay, except for crude protein (CP) and ether extract (EE). In vitro dry matter digestibility (INDMD) and in vitro crude protein digestibility (INCPD) were not affected by moisture content in baling process either. It was concluded that the moisture content during the baling process does not affect the chemical composition of star grass hay in advanced stadium of development, except for crude protein and ether extract.

Alkaloids content, cytotoxicity and anti-&lt;i&gt;Toxoplasma gondii&lt;/i&gt; activity of &lt;i&gt;Psidium guajava&lt;/i&gt; L. and &lt;i&gt;Tinospora crispa&lt;/i&gt;

The alkaloids content, cytotoxicity activity and anti-parasitic activity of Tinospora crispa Miers and Psidium guajava L. against parasite Toxoplasma gondii were investigated. Both of the crude plant extracts contained high amount of crude alkaloids and were not toxic to Vero cells (EC 50 >100 µg/mL). Following non-toxicity finding of the extracts, the in vitro anti-parasitic assay was carried out with clindamycin served as the positive control. T. crispa stem crude extract with EC 50 value of 7.71 ± 1.56 µg/mL, showed potential anti- T. gondii activity as the results were comparable to clindamycin (EC 50 = 6.24 ± 0.53 µg/mL). These findings suggest that stem extract of T. crispa Miers contained some potential active compounds against Toxoplasma gondii . Selective important alkaloids in the T. crispa stem fractions may be the key factor for their anti-parasitic activity. Further study is being carried out to investigate for potential bioactives present in the T. crispa extract through bioactivity guided fractionation.

The quality of crop fractions of a degraded Panicum maximum pasture under different cutting intervals and nitrogen fertilizer rates

The effects of cutting frequency and levels of nitrogen application on quality of crop fractions of a degradedPanicum maximum pasture was investigated in 2001 at Nsukka, Nigeria. Cutting intervals consisted of 3, 6, 9 and 12 weeks, while N rates were 0, 150, 300 and 450 kg-N ha-1. The percentage of P in the leaf, Na in all the fractions, Fe in the leaf and stem fractions, ash in the leaf and Zn in the leaf decreased significantly (P < 0.05) with increased interval between cuts. Nitrogen application increased significantly (P < 0.05) the percentage of P in all the fractions, and the percentage of Fe, K and Zn in the leaf compared with the control. Cutting every 3 weeks produced significantly (P < 0.05) higher concentrations of iron in the leaf and stem fractions than the other cutting intervals with application of 300 kg-N ha-1. The percentage of crude fibre in the stem increased significantly (P < 0.05) from 46 to 60% when the interval between cuts was increased from 6 to 9 weeks, while there was a 6% reduction in the crude fibre content of stem when nitrogen fertilizer was increased from 150 to 300 kg ha-1. Key words: Mineral composition, cutting frequency, crude fibre, ash content, Panicum maximum, pasture, nitrogen fertilizer.

Allocation of 14C assimilated in late spring to tissue and biochemical stem components of cork oak (Quercus suber L.) over the seasons

Carbon distribution in the stem of 2-year-old cork oak plants was studied by (14)CO(2) pulse labeling in late spring in order to trace the allocation of photoassimilates to tissue and biochemical stem components of cork oak. The fate of (14)C photoassimilated carbon was followed during two periods: the first 72 h (short-term study) and the first 52 weeks (long-term study) after the (14)CO(2) photosynthetic assimilation. The results showed that (14)C allocation to stem tissues was dependent on the time passed since photoassimilation and on the season of the year. In the first 3 h all (14)C was found in the polar extractives. After 3 h, it started to be allocated to other stem fractions. In 1 day, (14)C was allocated mostly to vascular cambium and, to a lesser extent, to primary phloem; no presence of (14)C was recorded for the periderm. However, translocation of (14)C to phellem was observed from 1 week after (14)CO(2) pulse labeling. The phellogen was not completely active in its entire circumference at labeling, unlike the vascular cambium; this was the tissue that accumulated most photoassimilated (14)C at the earliest sampling. The fraction of leaf-assimilated (14)C that was used by the stem peaked at 57% 1 week after (14)CO(2) plant exposure. The time lag between C photoassimilation and suberin accumulation was ∼8 h, but the most active period for suberin accumulation was between 3 and 7 days. Suberin, which represented only 1.77% of the stem weight, acted as a highly effective sink for the carbon photoassimilated in late spring since suberin specific radioactivity was much higher than for any other stem component as early as only 1 week after (14)C plant labeling. This trend was maintained throughout the whole experiment. The examination of microautoradiographs taken over 1 year provided a new method for quantifying xylem growth. Using this approach it was found that there was more secondary xylem growth in late spring than in other times of the year, because the calculated average cell division time was much shorter.

Yield and Nutritive Value Differences Among Cool-Season Grasses

Grasses are typically utilized at a vegetative stage of maturity under managed intensive rotational grazing. We compared the yield and nutritive value of the leaf and stem fraction, and total herbage of eight erect-growing, perennial cool-season grasses during 30-day intervals in the spring, summer, and fall at two Wisconsin locations. Total herbage production of all grasses was greatest during the spring as expected, but with the exception of smooth bromegrass, differences in leaf yield were relatively small. During the summer and fall, endophyte-infected and endophyte-free tall fescue produced the greatest leaf yield and quackgrass and smooth bromegrass the least. Significant leaf crude protein (CP) concentration differences among the eight grasses occurred during the spring, summer, and fall, but leaf CP of all grasses exceeded 16% and any differences would likely be inconsequential. Lowest neutral detergent fiber (NDF) and greatest NDF digestibility were measured in leaves of meadow fescue or timothy. Because yield differences among these grasses during the spring can be attributed primarily to the stem fraction and spring yield constitutes a large proportion of annual yield, a producer's perception of value to a grazing system may be biased by total yield estimates. The greater nutritive value of grasses like meadow fescue must be balanced against slightly lower productivity.

Bromatological evaluation of eleven corn cultivars harvested at two cutting heights

The objective of this study was to evaluate the chemical composition and dry matter in vitro digestibility of stem, leaf, straw, cob and kernel fractions of eleven corn (Zea mays) cultivars, harvested at two cutting heights. The experiment was designed as randomized blocks, with three replicates, in a 2 × 11 factorial arrangement (eleven cultivars and two cutting heights). The corn cultivars evaluated were D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FOR 01, CO 9621 and BR 205, harvested at a low cutting height (5 cm above ground) and a high cutting height (5 cm below the first ear insertion). Cutting height influenced the dry matter content of the stem fraction, which was lower (23.95%) in plants harvested at the low, than in plants harvested at the high cutting height (26.28%). The kernel fraction had the highest dry matter in vitro digestibility (85.13%), while cultivars did not differ between each other. Cob and straw were the fractions with the highest level of neutral detergent fiber (80.74 and 79.77%, respectively) and the lowest level of crude protein (3.84% and 3.69%, respectively). The leaf fraction had the highest crude protein content, both for plants of low and high cuttings (15.55% and 16.20%, respectively). The increase in the plant cutting height enhanced the dry matter content and dry matter in vitro digestibility of stem fraction, but did not affect the DM content of the leaf fraction.

P1-04-02: In Vitro Qualification and Quantification of Murine Mammary Stem/Progenitor Cells.

Abstract Increasing evidence suggest that tumors with a cell origin of more basal or stem-like sources are often highly metastatic and associated with poor prognosis. Identification of the cell of origin thus has important implications for development of new preventive and therapeutic approaches. To identifying the cells of origin of various breast cancers, understanding the normal cellular hierarchy within the breast tissue is an important prerequisite. However, current understanding of normal mammary stem/progenitor cell is limited due to the lack of a robust in vitro assay. The newly developed cell surface markers (CD24+CD49fhi) can only be used for low percent of enrichment. The only gold standard assay for functional evaluation of stem cell property is the in vivo transplantation of cleared mammary fat pad assay, yet this assay is expensive, time consuming, and requires highly trained skills, and thus cannot be used routinely for experiments. The goal of our study is thus to develop a robust in vitro assay to qualify and quantify murine mammary stem/progenitor cells. Our rationale lies on our recent findings of in vitro study of different fractions of murine stem/progenitor cells. When we use isolated primary epithelial cells for in vitro mammosphere formation, we found that stem cell enriched fraction and progenitor cell enriched fraction both formed very small mammospheres (≤ 50 μm) and these spheres appear to be of clonal origin (one cell gives rise to one sphere). When we plated these small spheres into 3D extracellular matrix for colony formation, however, they gave rise to two distinct structures: stem-enriched fraction generated predominately solid structure while progenitor-enriched fraction is dominated by hollow structures. Previous studies have linked the solid structure to the basal/myoepithelial lineage and the hollow structure to the luminal lineage. We thus suspected that the small mammospheres derived from the stem or progenitor enriched fractions could be originated from single stem or progenitor cell, and the number of spheres could indicate the number of original stem/progenitor cells within these enriched fractions. Subsequent in vivo transplantation with single sphere or single solid structure cultured in 3D extracellular matrix derived from green fluorescent protein transgenic mice proved that single sphere or 3D solid structure can repopulate the gland-free mammary fat pad. To conclude, the in vitro mammosphere formation in combination with subsequent differentiation in 3D extracellular matrix can be used as a robust in vitro assay for qualification and quantification of murine mammary stem/progenitor cells. This in vitro assay will greatly facilitate our understanding of genes regulate stem cell self-renewal, proliferation, differentiation as well as mechanisms keeping them at quiescent state within the niche. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-02.

Biomass allocation to leaves, stems and roots: meta‐analyses of interspecific variation and environmental control

We quantified the biomass allocation patterns to leaves, stems and roots in vegetative plants, and how this is influenced by the growth environment, plant size, evolutionary history and competition. Dose-response curves of allocation were constructed by means of a meta-analysis from a wide array of experimental data. They show that the fraction of whole-plant mass represented by leaves (LMF) increases most strongly with nutrients and decreases most strongly with light. Correction for size-induced allocation patterns diminishes the LMF-response to light, but makes the effect of temperature on LMF more apparent. There is a clear phylogenetic effect on allocation, as eudicots invest relatively more than monocots in leaves, as do gymnosperms compared with woody angiosperms. Plants grown at high densities show a clear increase in the stem fraction. However, in most comparisons across species groups or environmental factors, the variation in LMF is smaller than the variation in one of the other components of the growth analysis equation: the leaf area : leaf mass ratio (SLA). In competitive situations, the stem mass fraction increases to a smaller extent than the specific stem length (stem length : stem mass). Thus, we conclude that plants generally are less able to adjust allocation than to alter organ morphology.