Flavonoid patterns and systematics in Eleusine

A survey of leaf flavonoids was conducted on Eleusine coracana ssp. coracana and ssp. africana, E. indica, E. multiflora, E. tristachya, E. floccifolia, and E. compressa. Twenty phenolic compounds were detected. Those identified were: orientin, isoorientin, vitexin, isovitexin, saponarin, violanthin, lucenin-1, and tricin. The study revealed a general generic flavonoid pattern except for E. compressa, which occupies an isolated position in Eleusine. Flavonoids of the perennial E. floccifolia and the annuals E. multiflora and E. tristachya are markedly different from those of cultivated E. coracana, suggesting that these species are only distantly related to the crop. The morphologically well defined E. coracana—africana—indica group also forms a unit in respect of flavonoids. Subspecies africana exhibits a higher flavonoid similarity to ssp. coracana (finger millet) than does E. indica. The weedy race of ssp. africana usually combines flavonoids of both the wild and domesticated subspecies. The flavonoid pattern of the dedza race of ssp.africana is identical to that of finger millet, suggesting either a direct origin of the crop from this race, or extensive introgression from the crop into ssp. africana. A lack of qualitative differences in flavonoids between cultivated races of finger millet is indicative of the genetic stability of these compounds. The flavonoid data confirms the domestication of finger millet from ssp. africana.     

BIOSYSTEMATICS OF THE BOTHRIOCHLOA BARBINODIS COMPLEX (GRAMINEAE)

The New World species of Bothriochloa O. Kuntze are polyploids with 2n = 60, 120, 180 and 220 chromosomes and they reproduce sexually. Plants with 2n = 180 chromosomes constitute the extremely variable B. barbinodis (Lag.) Herter, which is subdivided into var. barbinodis, var. palmeri (Hack.) de Wet comb. nov., and var. schlumbergeri (Fourn.) de Wet comb. nov. The single collection with 2n = 220 chromosomes belongs with var. schlumbergeri. Plants resembling B. barbinodis in inflorescence structure but having well-developed pedicellate spikelets and 2n = 120 chromosomes are included in B. campii (Swallen) de Wet comb. nov. South American collections of B. springfieldii (Gould) Parodi differ from North American collections in having 2n = 60 rather than 120 chromosomes and in having larger inflorescences as does B. barbinodis. Variety australis de Wet. var. nov. is described to include them.     

Differential size distribution of atrial dense granules in spontaneously hypertensive, Wistar-Kyoto and Wistar rats

The differential size distribution of atrial dense granules (ADGs) in spontaneously hypertensive rats (SHR) and two normotensive controls, Wistar and Wistar-Kyoto (WKY) rats, was investigated. The ADGs in SHR were smaller than those in Wistar rats. The ADGs of WKY rats were of intermediate size. It is possible that ADGs are more rapidly secreted in SHR compared with WKY and Wistar rats or that the smaller-diameter granules may contain more atriopeptinogen than the larger granules. The intermediate size of the ADGs in WKY suggests that the WKY variant is morphologically intermediate between the SHR and Wistar strains.     

Histocytology of the avian (Gallus domesticus) carotid body.

The histotopography of the silvery-white glistening carotid body and the branchial derivates in the cranial thoracic inlets as well as the histocytology of the particular organ were revealed by various microtechniques. Three types of randomly distributed epithelioid cells, many capillaries, and small and large sinuses are observable. Myelinated fibres are sparsely distributed. 25 clinically healthy white leghorn males were used for this investigation.     

Smoking in Asthma Is Associated with Elevated Levels of Corticosteroid Resistant Sputum Cytokines—An Exploratory Study

Background

Current cigarette smoking is associated with reduced acute responses to corticosteroids and worse clinical outcomes in stable chronic asthma. The mechanism by which current smoking promotes this altered behavior is currently unclear. Whilst cytokines can induce corticosteroid insensitivity in-vitro, how current and former smoking affects airway cytokine concentrations and their responses to oral corticosteroids in stable chronic asthma is unclear.

Objectives

To examine blood and sputum cytokine concentrations in never, ex and current smokers with asthma before and after oral corticosteroids.

Methods

Exploratory study utilizing two weeks of oral dexamethasone (equivalent to 40 mg/day prednisolone) in 22 current, 21 never and 10 ex-smokers with asthma. Induced sputum supernatant and plasma was obtained before and after oral dexamethasone. 25 cytokines were measured by multiplex microbead system (Invitrogen, UK) on a Luminex platform.

Results

Smokers with asthma had elevated sputum cytokine interleukin (IL) -6, -7, and -12 concentrations compared to never smokers with asthma. Few sputum cytokine concentrations changed in response to dexamethasone IL-17 and IFNα increased in smokers, CCL4 increased in never smokers and CCL5 and CXCL10 reduced in ex-smokers with asthma. Ex-smokers with asthma appeared to have evidence of an ongoing corticosteroid resistant elevation of cytokines despite smoking cessation. Several plasma cytokines were lower in smokers with asthma compared to never smokers with asthma.

Conclusion

Cigarette smoking in asthma is associated with a corticosteroid insensitive increase in multiple airway cytokines. Distinct airway cytokine profiles are present in current smokers and never smokers with asthma and could provide an explanatory mechanism for the altered clinical behavior observed in smokers with asthma.     

Asymmetric Switching in a Homodimeric ABC Transporter: A Simulation Study

ABC transporters are a large family of membrane proteins involved in a variety of cellular processes, including multidrug and tumor resistance and ion channel regulation. Advances in the structural and functional understanding of ABC transporters have revealed that hydrolysis at the two canonical nucleotide-binding sites (NBSs) is co-operative and non-simultaneous. A conserved core architecture of bacterial and eukaryotic ABC exporters has been established, as exemplified by the crystal structure of the homodimeric multidrug exporter Sav1866. Currently, it is unclear how sequential ATP hydrolysis arises in a symmetric homodimeric transporter, since it implies at least transient asymmetry at the NBSs. We show by molecular dynamics simulation that the initially symmetric structure of Sav1866 readily undergoes asymmetric transitions at its NBSs in a pre-hydrolytic nucleotide configuration. MgATP-binding residues and a network of charged residues at the dimer interface are shown to form a sequence of putative molecular switches that allow ATP hydrolysis only at one NBS. We extend our findings to eukaryotic ABC exporters which often consist of two non-identical half-transporters, frequently with degeneracy substitutions at one of their two NBSs. Interestingly, many residues involved in asymmetric conformational switching in Sav1866 are substituted in degenerate eukaryotic NBS. This finding strengthens recent suggestions that the interplay of a consensus and a degenerate NBS in eukaroytic ABC proteins pre-determines the sequence of hydrolysis at the two NBSs.     

COUNTERFEIT HYBRIDS BETWEEN TRIPSACUM AND ZEA (GRAMINEAE)

Diploid (2n = 36) Tripsacum australe Cutler and Anderson var. hirsutum de Wet and Timothy, T. cundinamarce de Wet and Timothy, T. dactyloides (L.) L. var. dactyloides and var. meridonale de Wet and Timothy, and T. laxum Nash were crossed with Zea mays L. (2n = 20) as the pollen parent. True hybrids combine the cytologically nonreduced genome of Tripsacum (36 chromosomes) with the haploid (10 chromosomes) or more rarely diploid (20 chromosome) genome of Zea. Maternal offspring with 2n = 36 Tripsacum chromosomes commonly result from parthenogenetic development of cytologically nonreduced eggs. Some individuals with 2n = 36 Tripsacum chromosomes, however, resemble true hybrids in phenotype. These counterfeit hybrids incorporated Zea genetic material into their Tripsacum genomes without true fertilization having taken place. Offspring of counterfeit hybrids that were grown to maturity resembled their mothers in phenotype, and must have originated parthenogenetically. It is proposed that counterfeit hybrids are also produced in nature, and that this process contributes to origins of variation in gametophytic apomicts, and perhaps also in sexually reproducing species.