On the sexual reproduction ofDictyosiphon foeniculaceus (Phaeophyceae,Dictyosiphonales)

Dictyosiphon foeniculaceus from Sweden and Newfoundland was studied in laboratory culture. Zoids from unilocular sporangia developed into dioecious microscopic filamentous gametophytes which produced uniseriate plurilocular gametangia in low temperatures (0 to 8 °C). Zygotes and unfused isogametes gave rise to filamentous protonemata on which parenchymatous macroscopic sporophytes were formed. Isolates from Sweden and Newfoundland were interfertile. Although formed in culture, genetically unisexual sporophytes were not detected in nature. Female gametes ofD. foeniculaceus produced a sexual pheromone. It was identified as finavarrene, which is also known as the sperm attractant inAscophyllum nodosum.     

Immunocytochemical localization of growth hormone releasing factor (GHRF)-containing structures in the rat brain using anti-rat GHRF serum

The distribution of growth hormone releasing factor (GHRF) immunoreactive structures in the rat hypothalmus was studied after colchicine treatment with PAP immunocytochemistry in vibratome sections using an antiserum directed to rat hypothalamic GHRF. The majority of the GHRF-immunoreactive cell bodies were found in the arcuate nucleus, the medial perifornical region, and the ventral premammillary nuclei of the hypothalamus. Scattered cells were seen in the lateral basal hypothalamus, the medial and lateral portions of the ventromedial nucleus, and the dorsomedial and paraventricular nuclei. Immunoreactive fibers were observed in all the regions mentioned above. GHRF terminals were located in the central region of the median eminence. In addition, GHRF-immunoreactive neuronal processes were seen in the ventral region of the dorsomedial nucleus, the medial preoptic and suprachiasmatic regions, dorsal portion of the suprachiasmatic nucleus, bed nucleus of the stria terminals and the hypothalamic portion of the stria terminals. The localization of GHRF-immunoreactive terminals in the median eminence reinforces the view that GHRF plays a physiological role in the regulation of pituitary function. In addition, the localization of GHRF-immunoreactive structures in areas not usually considered to project to the median eminence suggest that GHRF may act as a neuromodulator or neurotransmitter.     

A Novel Highly Potent Autotaxin/ENPP2 Inhibitor Produces Prolonged Decreases in Plasma Lysophosphatidic Acid Formation In Vivo and Regulates Urethral Tension

Autotaxin, also known as ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2), is a secreted enzyme that has lysophospholipase D activity, which converts lysophosphatidylcholine to bioactive lysophosphatidic acid. Lysophosphatidic acid activates at least six G-protein coupled recpetors, which promote cell proliferation, survival, migration and muscle contraction. These physiological effects become dysfunctional in the pathology of cancer, fibrosis, and pain. To date, several autotaxin/ENPP2 inhibitors have been reported; however, none were able to completely and continuously inhibit autotaxin/ENPP2 in vivo. In this study, we report the discovery of a highly potent autotaxin/ENPP2 inhibitor, ONO-8430506, which decreased plasma lysophosphatidic acid formation.The IC₅₀ values of ONO-8540506 for lysophospholipase D activity were 6.4–19 nM for recombinant autotaxin/ENPP2 proteins and 4.7–11.6 nM for plasma from various animal species. Plasma lysophosphatidic acid formation during 1-h incubation was almost completely inhibited by the addition of >300 nM of the compound to human plasma. In addition, when administered orally to rats at a dose of 30 mg/kg, the compound demonstrated good pharmacokinetics in rats and persistently inhibited plasma lysophosphatidic acid formation even at 24 h after administration.Smooth muscle contraction is a known to be promoted by lysophosphatidic acid. In this study, we showed that dosing rats with ONO-8430506 decreased intraurethral pressure accompanied by urethral relaxation. These findings demonstrate the potential of this autotaxin/ENPP2 inhibitor for the treatment of various diseases caused by lysophosphatidic acid, including urethral obstructive disease such as benign prostatic hyperplasia.     

Heat shock factor 1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of bone marrow stem/progenitor cells

Bone marrow (BM)-derived stem/progenitor cells play an important role in ischemia-induced angiogenesis in cardiovascular diseases. Heat shock factor 1 (HSF1) is known to be induced in response to hypoxia and ischemia. We examined whether HSF1 contributes to ischemia-induced angiogenesis through the mobilization and recruitment of BM-derived stem/progenitor cells using HSF1-knockout (KO) mice. After the induction of ischemia, blood flow and microvessel density in the ischemic hindlimb were significantly lower in the HSF1-KO mice than in the wild-type (WT) mice. The mobilization of BM-derived Sca-1- and c-kit-positive cells in peripheral blood after ischemia was significantly lower in the HSF1-KO mice than in the WT mice. BM stem/progenitor cells from HSF1-KO mice showed a significant decrease in their recruitment to ischemic tissue and in migration, adhesion, and survival when compared with WT mice. Blood flow recovery in the ischemic hindlimb significantly decreased in WT mice receiving BM reconstitution with donor cells from HSF1-KO mice. Conversely, blood flow recovery in the ischemic hindlimb significantly increased in HSF1-KO mice receiving BM reconstitution with donor cells from WT mice. These findings suggest that HSF1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of BM-derived stem/progenitor cells.     

ACPA-negative RA consists of two genetically distinct subsets based on RF positivity in Japanese

HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10⁻⁶ and 0.0011, OR: 1.57 (1.28–1.91) and 1.37 (1.13–1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21–1.89) and 3.08 (1.68–5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote.     

Crossover interference in Saccharomyces cerevisiae requires a TID1/RDH54- and DMC1-dependent pathway

Two RecA-like recombinases, Rad51 and Dmc1, function together during double-strand break (DSB)-mediated meiotic recombination to promote homologous strand invasion in the budding yeast Saccharomyces cerevisiae. Two partially redundant proteins, Rad54 and Tid1/Rdh54, act as recombinase accessory factors. Here, tetrad analysis shows that mutants lacking Tid1 form four-viable-spore tetrads with levels of interhomolog crossover (CO) and noncrossover recombination similar to, or slightly greater than, those in wild type. Importantly, tid1 mutants show a marked defect in crossover interference, a mechanism that distributes crossover events nonrandomly along chromosomes during meiosis. Previous work showed that dmc1Delta mutants are strongly defective in strand invasion and meiotic progression and that these defects can be partially suppressed by increasing the copy number of RAD54. Tetrad analysis is used to show that meiotic recombination in RAD54-suppressed dmc1Delta cells is similar to that in tid1; the frequency of COs and gene conversions is near normal, but crossover interference is defective. These results support the proposal that crossover interference acts at the strand invasion stage of recombination.     

The Effect of Ostracism and Optional Participation on the Evolution of Cooperation in the Voluntary Public Goods Game

Not only animals, plants and microbes but also humans cooperate in groups. The evolution of cooperation in a group is an evolutionary puzzle, because defectors always obtain a higher benefit than cooperators. When people participate in a group, they evaluate group member’s reputations and then decide whether to participate in it. In some groups, membership is open to all who are willing to participate in the group. In other groups, a candidate is excluded from membership if group members regard the candidate’s reputation as bad. We developed an evolutionary game model and investigated how participation in groups and ostracism influence the evolution of cooperation in groups when group members play the voluntary public goods game, by means of computer simulation. When group membership is open to all candidates and those candidates can decide whether to participate in a group, cooperation cannot be sustainable. However, cooperation is sustainable when a candidate cannot be a member unless all group members admit them to membership. Therefore, it is not participation in a group but rather ostracism, which functions as costless punishment on defectors, that is essential to sustain cooperation in the voluntary public goods game.     

A multi-year assessment of the environmental impact of transgenic Eucalyptus trees harboring a bacterial choline oxidase gene on biomass,precinct vegetation and the microbial community

A 4-year field trial for the salt tolerant Eucalyptus globulus Labill. harboring the choline oxidase (codA) gene derived from the halobacterium Arthrobacter globiformis was conducted to assess the impact of transgenic versus non-transgenic trees on biomass production, the adjacent soil microbial communities and vegetation by monitoring growth parameters, seasonal changes in soil microbes and the allelopathic activity of leaves. Three independently-derived lines of transgenic E. globulus were compared with three independent non-transgenic lines including two elite clones. No significant differences in biomass production were detected between transgenic lines and non-transgenic controls derived from same seed bulk, while differences were seen compared to two elite clones. Significant differences in the number of soil microbes present were also detected at different sampling times but not between transgenic and non-transgenic lines. The allelopathic activity of leaves from both transgenic and non-transgenic lines also varied significantly with sampling time, but the allelopathic activity of leaves from transgenic lines did not differ significantly from those from non-transgenic lines. These results indicate that, for the observed variables, the impact on the environment of codA-transgenic E. globulus did not differ significantly from that of the non-transformed controls on this field trial.     

Arrest of cell cycle progression of HeLa cells in the early G1 phase in K+-depleted conditions and its recovery upon addition of insulin and LDL

Cell cycle progression of synchronized HeLa cells was studied by measuring labeling of the nuclei with [³H]thymidine. The progression was arrested in a chemically defined medium in which K⁺ was replaced by Rb⁺ (Rb-CDM) but was restored upon addition of insulin and/or low density lipoprotein (LDL). Cells started DNA synthesis 12 hr after addition of insulin and/or LDL, regardless of the time of arrest, suggesting their arrest early in the G1 phase. After incubation of cells in Rb-CDM containing insulin or LDL singly for 3, 6, or 9 hr, replacement of the medium by that without an addition resulted in marked delay in entry of cells into the S phase, but in its replacement by medium containing both agents, the delay was insignificant. Synthesis of bulk protein, estimated as increase in the cell volume, was not strongly inhibited. From these results we conclude that cell cycle progression of HeLa cells in K^?-depleted CDM is arrested early in the G1 phase and that the arrest is due to lack of some protein(s) required for entry into the S phase that is synthesized in the early G1 phase.