Study of Poaceae phenology in a Mediterranean climate. Which species contribute most to airborne pollen counts?

The present study sought to determine which of the common Poaceae species in the study area contribute most to the Poaceae pollen season curve, and to determine the phenological behaviour of the species studied. The different floral phenophases in thirty-three Poaceae species common in and around the city of Córdoba (SW Iberian Peninsula) were checked periodically over the period 2004–2006. Results showed that longer phenological ranges were recorded in the coolest and wettest year, and shorter ranges in the warmest and driest year. Moreover, ranges varied as a function of altitude: populations in lower-lying areas flowered earlier than those at higher altitudes. The results, taken in conjunction with the findings of preliminary research into potential pollen production, showed that probably only four of the Poaceae species studied—Dactylis glomerata, Lolium rigidum, Trisetaria panicea and Vulpia geniculata—were major contributors to the Poaceae airborne pollen curve.     

Taxonomic distribution and origins of the extended LHC (light-harvesting complex) antenna protein superfamily

Background  

The extended light-harvesting complex (LHC) protein superfamily is a centerpiece of eukaryotic photosynthesis, comprising the LHC family and several families involved in photoprotection, like the LHC-like and the photosystem II subunit S (PSBS). The evolution of this complex superfamily has long remained elusive, partially due to previously missing families.     

Cytological and mapping analysis of a novel male sterile type resulting from spontaneous floral organ homeotic conversion in marigold (<Emphasis Type="Italic">Tagetes erecta</Emphasis> L.)

A male sterile line was isolated in marigold (Tagetes erecta L.) and cytological analysis determined this to be a novel genic male sterility trait (Tems). Through the use of amplified fragment length polymorphisms (AFLPs) and bulked segregant analysis (BSA), tightly linked markers of Tems were identified with a view towards a map-based cloning strategy. It was found that spontaneous homeotic conversion of floral organs was the underlying cause of the male sterility in this marigold line. Thus, petals of male sterile plants resembled sepal-like structures and the stamens were partially converted to styles, although without the full characteristics or function of the true style organs. We have constructed a fine marker-based map for the Tems gene. This is intended to provide a tool for marker assisted selection (MAS) strategies in hybrid breeding and map-based cloning strategies for the male sterility locus. We discuss the significance of this spontaneously derived genic male sterility trait relating to the homeotic conversion of floral organs in marigold.     

It’s a knockout: CCN3 suppresses neointimal thickening

The role of CCN proteins in vivo is only just becoming understood. A prototypical member of the CCN family, CCN3 suppresses proliferation. In a study in press, Shimoyama and colleagues show that mice lacking CCN3 have a hyperproliferative response to vascular injury. These data, along with other recent observations, suggest that CCN3 may represent a novel therapy for hyperproliferative diseases.     

Nucleoside triphosphate pyrophosphatase of rabbit matrix vesicles, a mechanism for the generation of inorganic pyrophosphate in epiphyseal cartilage

Inorganic pyrophosphate (PPi) may be important in the regulation of mineralisation but its origin in epiphyseal cartilage is ill-defined. Nucleoside triphosphate pyrophosphatase is one potential source, as this enzyme catalyses the formation of PPi from nucleoside triphosphates. This enzyme has been identified in matrix vesicles derived from rabbit epiphyseal cartilage and a method developed to measure the activity using ATP as substrate in intact matrix vesicles under relatively physiological conditions. The enzyme had a high affinity for ATP (Km less than 10 microM) and was also active towards GTP, CTP and UTP. Disruption of the matrix vesicle membrane by sonication failed to alter the activity. Treatment of sonicated matrix vesicles with Triton X-100 increased the activity which may indicate a direct effect of the detergent on the enzyme. Activity towards ATP was inhibited substantially by ADP and AMP and by another potential substrate beta,gamma-methyleneadenosine 5'-triphosphate. Dichloromethylene bisphosphonate, an analogue of the product PPi, inhibited the activity to a lesser extent. Two other potential substrates, NADP+ and thymidine 5'-monophosphate p-nitrophenyl ester were only weakly inhibitory as was 1-hydroxyethylidene 1,1-bisphosphonate. These results imply that nucleoside triphosphates are the substrates in vivo and the inhibitory effects of ADP and AMP suggest mechanisms whereby this activity could be regulated.     

Mixed-chain phosphatidylcholine analogues modified in the choline moiety: preparation of isomerically pure phospholipids with bulky head groups and one acyl chain twice as long as the other

Diacylphosphatidylcholines were synthesized with widely different acyl chain lengths and bulky head groups. Lysophosphatidylcholine was acylated at room temperature within 6 h with a 10-fold molar excess of fatty acid anhydride in dry, alcohol-free chloroform in the presence of 1.2 equivalents of 4-pyrrolidinopyridine as a catalyst, affording the mixed-acid phosphatidylcholines with widely different chain lengths in more than 90% yield and with less than 1% acyl migration. The syntheses of isomerically pure 1-stearoyl-2-decanoyl- and 1-stearoyl-2-undecenoyl(delta 10)-sn-glycero-3-phosphocholines C(18:0)/C(10:0)-PC and C(18:0)/C(11:1 delta 10)-PC, respectively), followed by conversion to various head-group analogues, are illustrated here. The transition peak widths at half-height of the endotherms obtained by differential scanning calorimetry are consistent with very high isomeric purity. Phospholipase D from Streptomyces chromofuscus was used as a catalyst in the hydrolysis of C(18:0)/C(10:0-PC to give the corresponding phosphatidic acid in quantitative yield. The latter compound was condensed with 10 molar equivalents of various N,N,N-trialkylammonium alkanols (as their p-toluenesulfonate or tetraphenylborate salt) in the presence of trichloroacetonitrile in dry pyridine under nitrogen atmosphere to yield the C(18:0)/C(10:0) phospholipids bearing modified head groups, which were purified by flash chromatography.