Citrullination, a possible functional link between susceptibility genes and rheumatoid arthritis

Antibodies directed to citrullinated proteins (anti-cyclic citrullinated peptide) are highly specific for rheumatoid arthritis (RA). Recent data suggest that the antibodies may be involved in the disease process of RA and that several RA-associated genetic factors might be functionally linked to RA via modulation of the production of anti-cyclic citrullinated peptide antibodies or citrullinated antigens.     

Effects of Photoperiod, Temperature and Asynchrony between Thermoperiod and Photoperiod on Development to Panicle Initiation in Sorghum

The duration of the vegetative phase (i.e. days from sowingto panicle initiation) in sorghum [Sorghum bicolor (L.) Moench]is affected by photoperiod and temperature. Plants of severalcontrasting genotypes of sorghum were grown in controlled-environmentgrowth cabinets with either synchronous or asynchronous photoperiodsand thermoperiods. Apical development was recorded. Diurnalasynchrony between photoperiod and thermoperiod reduced durationsto panicle initiation when the temperature warmed after lightswent on and cooled after lights went off, but increased thesedurations when the temperature warmed before lights went onand cooled before lights went off. These effects were shownin the maturity lines 60M and SM100 and also in the USA cv.RS610 and the Sudanese landrace IS22365, but their magnitudevaried with genotype, photothermal regime, and the degree ofasynchrony. The greatest effect was detected in IS22365 grownat 30/21 °C (12 h/12 h) with a 12 h d^-1photoperiod whenthe temperature warmed 2.5 h before lights went on and cooled2.5 h before lights went off, when the duration from sowingto panicle initiation was 69 d compared with 37 d in the control(synchronous photoperiod and thermoperiod in each diurnal cycle). Reciprocal transfers of plants of IS22365 between short andlong days revealed that asynchrony principally affected theduration of the photoperiod-insensitive pre-inductive phaseof development; i.e. asynchrony affected the time (age) at whichthe plants were first able to respond to photoperiod. In thatinvestigation in controlled-environment growth chambers, thesubsequent photoperiod-sensitive inductive phase continued untilpanicle initiation. Subsequent reciprocal transfer experimentsin controlled-environment glasshouses in four different alternatingtemperature regimes employed synchronous photoperiods and thermoperiodsin short (11 h) days with temperature warming 1.5 h after thebeginning of the day in long (12.5 h) days. In those investigations,photoperiod sensitivity ended some time before (2.5–8.1d, mean 5.7 d) panicle initiation in IS22365, Naga White andSeredo. Moreover, whereas the duration of the photoperiod-insensitivepre-inductive phase was affected by temperature, the durationsof the photoperiod-sensitive inductive and the photoperiod-insensitivepost-inductive phases were not. Sorghum bicolor (L.) Moench; sorghum; asynchrony; photoperiod; thermoperiod; vegetative phase; panicle initiation     

An Intermediate Category of Seed Storage Behaviour?II. EFFECTS OF PROVENANCE, IMMATURITY, AND IMBIBITION ON DESICCATION-TOLERANCE IN COFFEE

Seeds of four cultivars of arabica coffee (Coffea arabica L.)received from three continents survived desiccation to between7-2% and 11-3% moisture content (wet basis), i.e. to seed waterpotentials of –90 MPa to –150 MPa, but further desiccationreduced germination (criterion, normal seedling development)in all seed lots. Only a few individuals from four of the lotsgerminated after being dried to 4–5% moisture content.Differences in desiccation sensitivity were apparent among lotswithin each cultivar. Desiccation sensitivity in these lotswas similar to that observed in seeds of orthodox species whichhave begun to germinate. Seeds extracted from fruits of intermediatematurity (yellow) were able to tolerate greater desiccationthan those from either ripe (red) or immature (green) fruits.Imbibed storage increased desiccation sensitivity. The resultsare compatible with the view that arabica coffee seeds are unableto tolerate extreme desiccation because germination has beeninitiated before harvest.     

Pre-Erythrocytic Development and Associated Host Responses to Haemoproteus meleagridis (Haemosporina: Haemoproteidae) in Experimentally Infected Domestic Turkeys12

ABSTRACT. Two generations of pre-erythrocytic schizogony occurred in skeletal and cardiac muscle of domestic turkeys infected with sporozoites of Haemoproteus meleagridis. First generation schizonts reached maturity approximately five days post-inoculation (DPI) and developed in capillary endothelial cells and myofibroblasts. The schizonts ranged from 12 to 20 μm in diameter and produced long (5–6 μm), slender merozoites. Early second generation schizonts were first detected in capillary endothelial cells between 5 and 8 DPI. They were cylindrical and ranged in size from 5 to 8 μm in diameter and up to 28 μm in length. Second generation schizonts which reached maturity by 17 DPI were surrounded by a thick, hyaline wall and were packed with numerous spherical merozoites less than 1 μm in diameter. Mature megaloschizonts were fusiform, ranged from 30 to 113 μm in diameter, and extended as much as 465 μm along the long axis of muscle fibers. Merozoites developed as buds from cytomeres that formed between 8 and 14 DPI. Infected turkeys developed a moderate to severe myositis within 5 DPI and were lame in one or both legs. The myositis was associated with the necrosis of scattered groups of muscle fibers. Muscle fibers surrounding mature megaloschizonts were swollen and hyaline. Megaloschizonts were surrounded occasionally by fibroblasts and infiltrates of mononuclear cells. The morphology and site of development of mature megaloschizonts of Haemoproteus meleagridis are contrasted with those of other avian haemosporidians.     

Environmental Control of Flowering in Barley (Hordeum vulgare L.). II. Rate of Developement as a Function of Temperature and Photoperiod and its Modification by Low-temperature Vernalization

Plants of six contrasting genotypes of barley were raised fromvernalized (imbibed at 1 °C for 30 d) or non-vernalizedseeds and grown in 12 different controlled environments comprisingfactorial combinations of three photoperiods (10, 13 and 16h d^–1), two day temperatures (18 and 28 °C) and twonight temperatures (5 and 13 °C). Except at longer daysfor Athenais or Arabi Abiad, the 28 °C day temperature wasgenerally supra-optimal and delayed awn emergence. At lowertemperatures and in photoperiods shorter than the critical value,P_C, which delay awn emergence, the time from sowing to awn emergencefor five of the genotypes conformed to the equation 1/f=a +bT{macron}+cPwhere f is the time to awn emergence (d), T{macron} is meandiurnal temperature (°C), P is photoperiod (h d^–1)and a, b and c are genotype-specific constants. In Arabi Abiad,however, significant responses to temperature were not detected.The low temperature pre-treatment of the seeds reduced the subsequenttime to awn emergence in Athenais and the autumn-sown genotypesAger, Arabi Abiad and Gerbel B, especially in longer days, buteither had no effect or tended to delay awn emergence in thespring-sown types Emir and Mona. In the spring-sown types P_Cwas outside the range investigated (i.e. > 16 h d^–1),but in Ager it was approx. 13 h d^–1 and in Gerbel B justover 13 h d^–1. For plants of Arabi Abiad grown from vernalizedseeds P_c was almost 15 h, but     

Photothermal Time for Flowering in Faba Bean (Vicia faba) and the Analysis of Potential Vernalization Responses

One cultivar and one land-race of faba bean were subjected to18 potentially vernalizing pre-treatments (constant temperaturesof 1, 5 or 9 °C factorially combined with photoperiods of8 or 16 h d^–1 for 10, 30 or 60 d), and then transferredinto four different growing regimes (‘day’/‘night’temperatures of 18/5 °C or 24/13 °C factorially combinedwith photoperiods of 11 or 16 h d–1). Control plants weregrown entirely in the latter four regimes. The times from sowingto appearance of first open flowers were recorded for all plants.Control plants of the land-race Zeidab Local flowered soonerin long days and in the warmer regime. Pre-treatment reducedthe subsequent time to flower in the four growing-on regimesbut most of the variation in the total time to first flowerfor the pre-treated plants was accounted for by differencesin the combined photothermal time accumulated in the two successiveenvironments - which was predicted by a simple photothermalmodel. Thus, there was neither a specific low-temperature nora short-day vernalization response in this accession. Similarly,no true low-temperature or short-day vernalization responsewas detected in the cv. Maris Bead. However, this UK cultivarflowered later than predicted in the 24/13 °C regime, indicatingthat the 24 °C ‘day’ temperature was supraoptimal.Delays to flowering at 24/13 °C were, however, less evidentwhen plants were grown in long days or following prolonged (30–60d) pre-treatments at cool temperatures. Viciafaba faba, bean, flowering, photoperiodism, vernalization, photothermal time, screening germplasm.     

The Influence of Pre and Post-storage Hydration Treatments on Chromosomal Aberrations, Seedling Abnormalities, and Viability of Lettuce Seeds

A 2 h soaking treatment in distilled water, or in aqueous solutionsof cysteine, potassium iodide, or sodium thiosulphate, had nosignificant effect (P > 0.25) on the subsequent longevityof lettuce seeds (Lactuca sativa L.) in two different storageenvironments. Neither did these treatments influence relationsbetween loss in germination and the frequency of chromosomalaberrations observed during first mitoses after storage. Incontrast partial hydration of lettuce seeds after storage byexposure to moist air (humidification) or to an osmoticum (priming)reversed some of the damage which resulted from ageing. Mostof the benefits occurred during the first 3 d of humidificationduring which seed moisture content rose to 34 per cent, or duringthe first 7 d of priming when seed moisture content increasedto 44 per cent. Both post-storage hydration treatments reducedthe frequency of chromosomal aberrations, increased the rateof root growth, and decreased the frequency of morphologicallyabnormal seedlings. Either treatment could be of practical use,but it is suggested that humidification is more convenient.Consideration should be given to adopting a humidification treatmentas standard practice following long-term seed storage for geneticconservation. Lactuca sativa, lettuce, seed storage, seed viability, chemical pre-treatment, seed longevity, seed humidification (conditioning), seed priming, chromosome repair, seedling abnormalities