Sugar transformations associated with hexose transport in immature internodal tissue of sugar cane

After a 15 sec incubation in d-glucose-¹⁴C(U), 53–70% of the intracellular radioactivity in immature internodal tissue of sugarcane was in glucose-6-phosphate, and the remainder was in free glucose. Two unmetabolized glucose analogs, 2-deoxy-d-glucosce and 3-O-methyl-d-glucose, were transported at rates comparable to glucose but neither of these analogs was phosphorylated. Doubly-labeled d-glucose-1-¹⁴C-6-phosphate-³²P was dephosphorylated prior to deposition in the inner space, and ¹⁴C was transported into this tissue twice as rapidly as ³²P. It was also shown that ³²P in exogenously supplied glucose-6-³²P was not the source of phosphate for the intracellular synthesis of glucose-6-P. Galactose transport was similar to that of glucose in that the first major product recovered intracellularly was a phosphorylated sugar, i.e. ¹⁴C-galactose-1-P, when the tissue was incubated in d-galactose-¹⁴C(U). Although fructose, glucose, and galactose competed for transport into this tissue, free fructose and glucose predominated in the tissue extract after a 15-sce incubation in d-fructose-¹⁴C(U). This contrasted sharply, with the products of ¹⁴C-glucose transport which were comprised of phosphorylated sugars after 15 sec.     

Characterization and inhibition of invertases in sugar cane juice

(NH₄)₂SO₄ fractionation followed by Sephadex G-200 chromatography of sugar cane juice gave an acid invertase with MW of 380 000 and 23.5% carbohydrate and a neutral invertase with MW of 66 000 and 22% carbohydrate. For acid invertase, K_m is 2.8 mM and V_max is 2.7 μmol sucrose hydrolysed/hr/mg protein. For neutral invertase, K_m and V_max are 0.32 mM and 2.8 μmol hydrolysed/hr/mg protein, respectively. Inhibition of both invertases by either lauryl sulfate or metasilicate is not competitive.     

Molasses melanoidin-like products enhance phytoextraction of lead through three Brassica species

Previously, it has been suggested that melanoidin-like products (MLP) from sugarcane molasses may accelerate copper phytoextraction. In this study, we evaluated the facilitatory effect of MLP on phytoextraction in a medium including cadmium or lead, the concentrations of which were adjusted around the regulation values of the Soil Contamination Countermeasures Act in Japan. Three Brassica species were tested based on their fast growth, high biomass productivity, and high heavy metal absorption. Both biomass and lead uptake in the nutrient medium with 1 mM lead nitrate were significantly increased by the addition of MLP, and almost all of the lead was accumulated in the root tissue. Therefore, MLP were able both to detoxify lead ions and to improve their bioavailability in Brassica species. In contrast, only these species with MLP or citric acid survived in the nutrient medium with 1 mM cadmium sulfate. The phytoextraction of cadmium using these species was therefore impractical under the Act.     

Continuous ethanol production by thermotolerant Kluyveromyces marxianus IMB3 immobilized on mineral Kissiris at 45°C

Thermotolerant Kluyveromyces marxianus var. marxianus IMB3 yeast strain was immobilized on Kissiris (mineral glass foam derived from lava) in column packed reactors, and used for ethanol production from glucose or molasses under continuous culture conditions at temperatures between 40 and 50°C. Both ethanol yield and fermentation efficiency were highest at 45°C and a dilution rate (D) of 0.15/h. Increasing sugar concentration led to an increase in ethanol yield of up to 68.6 and 55.9 g/l on approx. 200g glucose or molasses, respectively. Optimum fermentation efficiency (experimental yields over theoretical maximum yields) however was at about 15% sugar for both glucose and molasses. Slight aeration (25 ml of air/min) through the medium addition line was found advantageous due to its mixing effect and probable maintenance of activity.     

Production of alcohol from sugar beet molasses without heat or filter sterilization

Among three esters of p-hydroxybenzoate, n-butyl p-hydroxybenzoate was selected as the best antimicrobial substance. Molasses medium sterilized by this ester was used as a substrate for ethanol production. n-Butyl p-hydroxybenzoate (0.15% w/v) completely inhibited the growth of free yeast cell inoculum, Ca-alginate immobilized yeast inoculum and bacterial contaminants. Immobilization of the yeast cell inoculum in Ca-alginate with castor oil (6% v/v) offered a yeast cell protection against the inhibitory effect of n-butyl p-hydroxybenzoate. The presence of castor oil in this immobilization system did not affect the metabolic activity of the yeast in beads compared to the cells immobilized without castor oil. The yeast cell beads in this system completely utilized up to 25% molasses sugar with an ethanol yield of 10.58%, equal to 83% of its theoretical value. The beads were stable and could be used successfully for seven cycles of batch fermentation. The optimum fermentation temperature using this system was 35°C. Received 21 January 1997/ Accepted in revised form 05 May 1997     

Establishment of the Woody Grass Arundinaria gigantea for Riparian Restoration

Canebrakes are dense stands of Arundinaria gigantea (Walt.) Muhl. that covered large areas of the southeastern North America. With agricultural development, canebrakes were quickly converted to crop and pastureland and now occur only in small, isolated patches. There is growing interest in the use of A. gigantea and other temperate bamboo species in riparian and floodplain revegetation in North America, but lack of detailed information on propagation and management of woody perennial grasses hinders reestablishment activities. Our study assesses the influence of nutrient and woodchip mulch amendments on survival and growth of A. gigantea transplanted as part of a riparian restoration project in central Kentucky. After two growing seasons, culm number (aboveground stems) increased 4‐fold and extent of transplanted clumps expanded 26‐fold. The survival rate of transplanted cane clumps was 98%. Hardwood chip mulch significantly increased the emergence of new culms, culm height growth, and clump area. Composted manure, applied at a rate that contributed a similar mass of organic matter as the hardwood mulch, also significantly increased new culm number and clump area. Our findings demonstrate that addition of manure or hardwood mulch can significantly enhance aboveground production of A. gigantea transplants. However, survival and initial growth of untreated clumps were also adequate in this study. It appears that careful site selection, transplantation, and site maintenance may be sufficient to ensure A. gigantea establishment on many sites. Practitioners should assess soil drainage, water stress, and fertility along with herbaceous competition and incidence of overbank flooding before determining the necessity of organic amendments to supplement establishment of A. gigantea or other woody grasses for riparian restoration.     

Spittlebug indicators of nitrogen-fixing plants

Abstract.

• 1 Spittlebugs (Homoptera: Cercopoidea) are preferentially associated with nitrogen-fixing angiosperms. Generally, the Aphrophoridae associate with legumes, the Clastopteridae with actinorhizal plants, and the Cercopidae with associative nitrogen-fixing grasses. This is the first reported insect—host association specific to nitrogen-fixing plants.
• 2 It is probable that spittlebugs are attracted to nitrogen-fixing plants because these hosts provide a relatively rich, reliable source of organic nitrogen compounds for xylem-sucking insects.
• 3 Many spittlebugs live on plants that do not fix nitrogen, and ecological, mechanical or chemical factors may bar some spittlebugs from otherwise suitable nitrogen-fixing plants.
• 4 Among nitrogen-fixing hosts, spittlebugs appear to prefer plants that transport fixed nitrogen as amino acids and amides to plants that transport fixed nitrogen as ureides.

     

A scanning electron microscope study of the stem structure in the West African Cane Palms (Calamoideae)

The canes of thirteen rattan taxa comprising two Calamus, three Eremospatha, five Laccosperma and three Oncocalamus were studied anatomically by scanning electron microscopy (SEM). Six out of the taxa tagged L. secundiflorum a, b, c; Oncocalamus sp. d, Oncocalmus sp. e and Calamus sp. f were unresolved herbarium voucher specimens many decades old. SEM photomicrographs revealed cell‐tissue specific differences in anticlinal cell wall of the epidermis, fibrous sheaths, sheath parenchyma and phloem strands, leaf traces, and vessel diam‐ eter. Metaxylem vessel diameters varied between 20–212 µm in the outer peripheral zone and 90–310 µm in the central cylinder, except in L. secundiflorium c where the trend is reversed. Regression analysis of the metaxylem diameter values along radial distance shows large interspecific differences from central to outer cylinder. The weak R² values (P ≤ 0.5) in nine of the thirteen species suggests that other unmeasured variables contribute to the observed trend. The structure of the unresolved voucher specimens appear to follow the same general trend in the identified specimens suggestive of phenotypic divergence between po‐ pulations brought about by developmental plasti‐ city. The leaf trace observed in Oncocalamus sp. e is unique and deserved to be examined more closely. A simple arithmetical expression indicat‐ ing structural synergy between protoxylem and metaxylem for possible volume ratio balance is included. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)