The incidence of japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop.
(33/2581)
The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens. (+info)
The incidence of Japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop.
(34/2581)
The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens. (+info)
Allergen mimotopes in food enhance type I allergic reactions in mice.
(35/2581)
BIP1is a murine IgG antibody capable of enhancing the IgE binding to Bet v 1, the major birch pollen allergen. We have previously generated a mimotope of BIP1, designated Bet mim 1, from a constrained phage display peptide library. We demonstrated that oral immunization of BALB/c mice with the Bet mim 1 mimotope resulted in the induction of Bet v 1-specific IgG. The aim of this study was to test the influence of such an oral immunization with Bet mim 1 on a subsequent type I allergic response to Bet v 1. Phages displaying Bet mim 1 or control mimotopes, or PBS alone, were delivered to BALB/c mice by intragastric gavages prior to systemic sensitization with recombinant Bet v 1 and Al(OH)(3), an adjuvant inducing preferentially IgE antibody responses. Only mice fed with Bet mim 1-phages displayed substantially enhanced type I allergic skin reactivity to Bet v 1, as compared to mice pretreated with control mimotopes or PBS. A gastric digestion assay indicated that Bet v 1 and its homologue from apple, Mal d 1, were degraded within seconds under physiological conditions. In contrast, phage-displayed mimotopes were resistant to digestion. Our data indicate that allergen mimics in the diet that resist digestion, can induce allergen specific IgG able to enhance an allergic response. We therefore conclude that sensitization via the oral route may represent a mechanism for aggravating type I allergic reactions, probably leading to an earlier onset of symptoms even at lower allergen dosage. (+info)
Meiotic drive of chromosomal knobs reshaped the maize genome.
(36/2581)
Meiotic drive is the subversion of meiosis so that particular genes are preferentially transmitted to the progeny. Meiotic drive generally causes the preferential segregation of small regions of the genome; however, in maize we propose that meiotic drive is responsible for the evolution of large repetitive DNA arrays on all chromosomes. A maize meiotic drive locus found on an uncommon form of chromosome 10 [abnormal 10 (Ab10)] may be largely responsible for the evolution of heterochromatic chromosomal knobs, which can confer meiotic drive potential to every maize chromosome. Simulations were used to illustrate the dynamics of this meiotic drive model and suggest knobs might be deleterious in the absence of Ab10. Chromosomal knob data from maize's wild relatives (Zea mays ssp. parviglumis and mexicana) and phylogenetic comparisons demonstrated that the evolution of knob size, frequency, and chromosomal position agreed with the meiotic drive hypothesis. Knob chromosomal position was incompatible with the hypothesis that knob repetitive DNA is neutral or slightly deleterious to the genome. We also show that environmental factors and transposition may play a role in the evolution of knobs. Because knobs occur at multiple locations on all maize chromosomes, the combined effects of meiotic drive and genetic linkage may have reshaped genetic diversity throughout the maize genome in response to the presence of Ab10. Meiotic drive may be a major force of genome evolution, allowing revolutionary changes in genome structure and diversity over short evolutionary periods. (+info)
Starch and the control of kernel number in maize at low water potentials.
(37/2581)
After reproduction is initiated in plants, subsequent reproductive development is sometimes interrupted, which decreases the final number of seeds and fruits. We subjected maize (Zea mays L.) to low water potentials (psi(w)) that frequently cause this kind of failure. We observed metabolite pools and enzyme activities in the developing ovaries while we manipulated the sugar stream by feeding sucrose (Suc) to the stems. Low psi(w) imposed for 5 d around pollination allowed embryos to form, but abortion occurred and kernel number decreased markedly. The ovary contained starch that nearly disappeared during this abortion. Analyses showed that all of the intermediates in starch synthesis were depleted. However, when labeled Suc was fed to the stems, label arrived at the ovaries. Solute accumulated and caused osmotic adjustment. Suc accumulated, but other intermediates did not, showing that a partial block in starch synthesis occurred at the first step in Suc utilization. This step was mediated by invertase, which had low activity. Because of the block, Suc feeding only partially prevented starch disappearance and abortion. These results indicate that young embryos abort when the sugar stream is interrupted sufficiently to deplete starch during early ovary development, and this abortion results in a loss of mature seeds and fruits. At low psi(w), maintaining the sugar stream partially prevented the abortion, but invertase regulated the synthesis of ovary starch and partially prevented full recovery. (+info)
Control of pollen tube tip growth by a Rop GTPase-dependent pathway that leads to tip-localized calcium influx.
(38/2581)
We have shown that Rop1At, a pollen-specific Rop GTPase that is a member of the Rho family of small GTP binding proteins, acts as a key molecular switch controlling tip growth in Arabidopsis pollen tubes. Pollen-specific expression of constitutively active rop1at mutants induced isotropic growth of pollen tubes. Overexpression of wild-type Arabidopsis Rop1At led to ectopic accumulation of Rop1At in the plasma membrane at the tip and caused depolarization of pollen tube growth, which was less severe than that induced by the constitutively active rop1at. These results indicate that both Rop1At signaling and polar localization are critical for controlling the site of tip growth. Dominant negative rop1at mutants or antisense rop1at RNA inhibited tube growth at 0.5 mM extracellular Ca(2+), but growth inhibition was reversed by higher extracellular Ca(2+). Injection of anti-Rop antibodies disrupted the tip-focused intracellular Ca(2+) gradient known to be crucial for tip growth. These studies provide strong evidence for a Rop GTPase-dependent tip growth pathway that couples the control of growth sites with the rate of tip growth through the regulation of tip-localized extracellular Ca(2+) influxes and formation of the tip-high intracellular Ca(2+) gradient in pollen tubes. (+info)
Antisense-mediated silencing of a gene encoding a major ryegrass pollen allergen.
(39/2581)
Type 1 allergic reactions, such as hay fever and allergic asthma, triggered by grass pollen allergens are a global health problem that affects approximately 20% of the population in cool, temperate climates. Ryegrass is the dominant source of allergens because of its prodigious production of airborne pollen. Lol p 5 is the major allergenic protein of ryegrass pollen, judging from the fact that almost all of the individuals allergic to grass pollen show presence of serum IgE antibodies against this protein. Moreover, nearly two-thirds of the IgE reactivity of ryegrass pollen has been attributed to this protein. Therefore, it can be expected that down-regulation of Lol p 5 production can significantly reduce the allergic potential of ryegrass pollen. Here, we report down-regulation of Lol p 5 with an antisense construct targeted to the Lol p 5 gene in ryegrass. The expression of antisense RNA was regulated by a pollen-specific promoter. Immunoblot analysis of proteins with allergen-specific antibodies did not detect Lol p 5 in the transgenic pollen. The transgenic pollen showed remarkably reduced allergenicity as reflected by low IgE-binding capacity of pollen extract as compared with that of control pollen. The transgenic ryegrass plants in which Lol p 5 gene expression is perturbed showed normal fertile pollen development, indicating that genetic engineering of hypoallergenic grass plants is possible. (+info)
Genetic architecture of species differences in annual sunflowers: implications for adaptive trait introgression.
(40/2581)
Genetic architecture may profoundly influence the ability of adaptive traits to spread between species via introgressive hybridization. Here, we examine the genomic location of quantitative trait loci (QTL) associated with pollen sterility and morphological traits distinguishing two annual sunflowers, Helianthus annuus and H. debilis ssp. cucumerifolius. These species are of particular interest since they hybridize naturally, and the form of H. annuus in Texas (called ssp. texanus) is thought to have arisen through introgression. Analysis of 226 BC(1) progeny from a cross between H. annuus and H. debilis revealed 56 QTL for 15 morphological traits and 2 QTL for pollen sterility. Four morphological QTL are tightly linked (<10 cM) to one or more sterility factors and 7 are closely allied with underrepresented and presumably negatively selected chromosomal blocks. Although these 11 QTL seem unlikely to move between the species, no barrier to introgression was detected for the remaining 45 morphological QTL. In fact, due to widespread pleiotropy (or tight linkage), the introgression of just three small chromosomal blocks appears sufficient to largely recover the phenotype of ssp. texanus. Subsequent work will test for the occurrence and fitness consequences of the identified QTL in natural populations of ssp. texanus. (+info)