Purification and Partial Characterization of Polysaccharides From Coconut Milk

Ethanol-precipitated polysaccharides of the liquid endospermof coconut, Cocos nucifera L., were composed predominantly ofgalactose and arabinose with minor amounts of mannose and glucose.Gel filtration chromatography on Bio-Gel A-0.5 m revealed asingle major peak (Peak A) at the void volume and a minor peak(Peak B) partially included in the column volume. Peak A containedsome uronosyl residues, but was not susceptible to cleavageby endopolygalacturonase, indicating that it does not containsignificant amounts of polygalacturonic acid. Neutral glycosylresidue composition analysis of Peak A showed that it consistedof 72% galactose and 24% arabinose with minor amounts of glucoseand rhamnose. Coconut milk, Cocos nuciferaL, polysaccharides, glycosyl composition     

Comparative vegetative anatomy and systematics of Spiranthoideae (Orchidaceae)

STERN, W. L., MORRIS, M. W., JUDD, W. S., PRIDGEON, A. M. & DRESSLER, R. L. 1993. Comparative vegetative anatomy and systematics of Spiranthoideae (Orchidaceae). The anatomy of leaf, stem and root of plants in the orchid subfamily Spiranthoideae was studied and described from the viewpoint of systematics. Plants were available from most of the geographic range. Tribes Diceratosteleae and Tropidieae show sinuous anticlinal epidermal cell walls in leaves, glandular foliar hairs, tetracytic para-mesoperigenous stomata, unitary tracheary components in the foliar midrib, foliar and cauline stegmata and sclerenchyma, typical cruciate starch grains, thick-walled exodermal, endodermal, and pericyclic cells, and conductive strands of the root embedded in sclerenchyma. The tribe Cranichideae shows straight to curvilinear anticlinal epidermal cell walls in leaves, lack glandular foliar hairs, have variably patterned mesoperigenous stomata, lack sclerenchyma throughout the parts studied, have a binary tracheary component in the foliar midrib, store starch in specialized amyloplasts (spiranthosomes), lack stegmata, have thin-walled exodermal, endodermal, and pericyclic cells, show scalariform thickenings in exodermal cells, and have conductive strands of the root embedded in parenchyma. In Cryptostylis the tracheary component of the foliar midrib is unitary, stomata lack subsidiary cells, starch grains are of the typical cruciate configuration, and passage cells of the endodermis are apparently associated with tilosomes. Anatomical data, when analysed cladistically, support the hypothesis that Spiranthoideae, as currently delimited, are polyphyletic. Corymborkis, Tropidia, and Diceratostele are more closely related to Palmorchis, a likely representative of a basal clade within subfamily Epidendroideae, than to genera of Cranichideae. Likewise, members of Cranichideae are more closely related to Diuris, a representative of subfamily Orchidoideae-tribe Diurideae, than to Corymborkis, Tropidia and Diceratostele. The Corymborkis– Tropidia-Diceratostele-bassd epidendroid [Palmorchis) clade may be diagnosed by the foliar synapomorphies of sinuous anticlinal walls of epidermal cells and presence of glandular hairs. The Cranichideae-orchidoid (Diuris) clade may be diagnosed by its variably patterned, mesoperigenous stomata, lack of vascular bundle sclerenchyma, absence of stegmata, unthickened endodermal cell walls in roots, and conductive cells of roots embedded in parenchyma. Relationships within this clade are quite unresolved, when only anatomical data are employed; however, all studied genera of Cranichideae, except Cryptostylis, possess a binary tracheary component in the foliar midrib. Cranichideae, excluding Cryptostylis, may be considered monophyletic. All Cranichideae, except Helaeria and Cryptostylis, possess spiranthosomes. Hetaeria may be a basal member within Cranichideae. We consider the phylogenetic position of Cryptostylis, in relation to Cranichideae vs. Diurideae, to be equivocal.     

Morphology and Infraciliature of Three Species of Eutintinnus (Ciliophora; Tintinnina) with Guidelines for Interpreting Protargol-Stained Tintinnine Ciliates

ABSTRACT. The infraciliatures of three Chesapeake Bay species of Eutintinnus conforming in lorica morphology to E. angustatus, E. pectinis , and E. tenuis were compared following Protargol silver impregnation. The kinetome of these species had a number of shared attributes including: 1) a right and left field that were of similar length and kinetal spacing; 2) two, rarely three, long dorsal kineties composed of monokinetids; 3) a ventral kinety; and 4) the absence of a true posterior kinety. Nonetheless, the specific organization of infraciliary components varied considerably among species. For example, the organization of the ventral kinety and several kineties along the border of the left field was different in all three species. In addition, the dorsal kineties of E. angustatus differed positionally from those of E. pectinis and E. tenuis . Some divergence in oral infraciliature was also noted, with the arrangement of infundibular oral polykinetids in E. pectinis and E. tenuis being distinct from that of E. angustatus . The amount of variation in the infraciliature of Eutintinnus spp. was much greater than previously noted for congeneric species of tintinnines and supports the separation E. angustatus, E. pectinis , and E. tenuis at the generic or subgeneric level.     

Structure of Lamprey Haemoglobin

The crystal structure of haemoglobin V from the sea lamprey Petromyzon marinushas been analysed by X-ray diffraction. This report describes the structure of the cyanide complex of methaemo-globin crystals, type D₂.     

On the Mechanism of Action of <Emphasis Type="Italic">lac</Emphasis> Repressor

Chen et al. have proved conclusively that lac repressor and RNA polymerase bind independently to wild type lac DNA in vitro. To explain the lacp ^s mutation, which causes competitive binding between repressor and polymerase, they suggest that a new promoter site has been created near the lac operator.     

Yield of wheat across a subambient carbon dioxide gradient

Yields and yield components of two cultivars of day-neutral spring wheat ( Triticum aestivum L.) were assessed along a gradient of daytime carbon dioxide (CO₂) concentrations from about 200 to near 350 μmol CO₂ (mol air)^–1 in a 38 m-long controlled environment chamber. The range in CO₂ concentration studied approximates that of Earth's atmosphere since the last ice age. This 75% rise in CO₂ concentration increased grain yields more than 200% under well-watered conditions and by 80–150% when wheat was grown without additions of water during the last half of the 100-day growing season. The 27% increase in CO₂ from the pre-industrial level of 150 years ago (275 μmol mol^–1) to near the current concentration (350 μmol mol^–1) increased grain yields of 'Yaqui 54' and 'Seri M82' spring wheats by 55% and 53%, respectively, under well-watered conditions. Yield increased because of greater numbers of grains per spike, rather than heavier grains or numbers of spikes per plant. Water use increased little with CO₂ concentration, resulting in improved water use efficiency as CO₂ rose. Data suggest that rising CO₂ concentration contributed to the substantial increase in average wheat yields in the U.S. during recent decades.     

Seedling density modifies the growth responses of yellow birch maternal families to elevated carbon dioxide

We studied seedling growth responses to ambient and elevated CO₂ (350 and 700 μL L^?1) of three maternal families of yellow birch (Betula alleghaniensis), raised both individually and in high-density stands. Seedlings in competitive, dense stands exhibited markedly lower average CO₂-induced growth enhancements than individually grown plants (16% vs. 49%). Maternal families differed in their growth responses to elevated CO₂. However, differences among families were contingent upon density; families which exhibited the greatest CO₂-induced growth at low density exhibited the least CO₂-responsiveness at high density. These data are discussed in two separate contexts; the reliability of estimates of the CO² fertilization potential of forest species based solely on individually grown plants, and the potential evolutionary consequences of rising CO₂ on regenerating forest tree populations.     

Kyaroikeus cetarius N. G., N. Sp.: A Parasitic Ciliate from the Respiratory Tract of Odonticete Cetacea

ABSTRACT. Examination of mucus discharged from the blowholes of live odonticete Cetacea and material collected from nasal orifices of dead hosts routinely revealed infestations of a large spindle-shaped ciliate. Kyaroikeus cetarius n. g., n. sp. These ciliates had a prominent posterior podite and were holotrichously ciliated except for a conspicuous bipolar stripe extending along the left margin of the cell. Most specimens were free-swimming and moved slowly through freshly collected mucus, but some individuals were attached to host cells or cellular debris by a transparent thread secreted from the podite. The oral architecture of protargol-impregnated K. cetarius consisted of one preoral and two circumoral kinetics set within a deep oral cavity continuous with an extensive, posteriorly directed cytopharynx. Somatic kineties were composed entirely of monokinetids and formed an expansive right ciliary field covering most of the cell surface, a reduced left ciliary field adjacent to the oral cavity, and a group of four kinetal fragments located mid-ventrally within a shallow pocket. Subkinetal microtubules were associated with the kineties of the right and left fields, and the non-ciliated stripe was underlain by a series of longitudinal fibers. The ciliate's large, heteromeric macronucleus was centrally positioned and clearly evident in living or stained specimens, while the ellipsoid micronucleus was located adjacent to the cytopharynx and often inconspicuous. K. cetarius has several morphological attributes typical of phyllopharyngian ciliates (e.g., adhesive organelle, heteromeric macronucleus, somatic kineties of monokinetids, subkinetal microtubules), and, except for its nearly holotrichous ciliation, most closely resembles dysteriine ciliates.