Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism

Fig trees are pollinated by fig wasps, which also oviposit in female flowers. The wasp larvae gall and eat developing seeds. Although fig trees benefit from allowing wasps to oviposit, because the wasp offspring disperse pollen, figs must prevent wasps fr

Length polymorphism of thymidylate synthase regulatory region in Chinese populations and evolution of the novel alleles

The tandemly repeated 28-bp sequence in the 5'-terminal regulatory, region of human thymidylate synthase (TSER), which has been reported to be polymorphic in different populations, was surveyed in 668 Chinese from 9 Han groups, 8 ethnic populations, and 3

Some biocybernetic aspects in gene expression and regulatory control

In eucaryotes, gene expression and control is a complex nonlinear process, where there are many control mechanisms and ways, both physic, chemical and informational control. By the exploration from the angle of biocybernetics, the authors suggest that gene expression is a co-control process. In this process, physic, chemical and informational feedback controls are associated and influential each other, and are cross and co-functional. The physic, chemical and informational control ways composed an order non-linear feedback control system in eucaryotes.

The application of in vitro sperm competition test to evaluate the impact of ZP-derived peptides on fertilization capacity of cat sperm

The present study aimed to establish a sensitive in vitro assay to assess the binding capacity of cat spermatozoa. Cat oocytes and epididymal sperm cells were isolated from gonads and cultured for in vitro fertilization. Before fertilization, the sperm ce

Opiate withdrawal induces dynamic-expressions of AMPA receptors and its regulatory molecule CaMKII alpha in hippocampal synapses

Adaptive changes in brain areas following drug withdrawal are believed to contribute to drug seeking and relapse. Cocaine withdrawal alters the expression of GluR1 and GluR2/3 subunits of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) rec

MATING COMPETITION AND INTERGROUP TRANSFER OF MALES IN TIBETAN MACAQUES (MACACA-THIBETANA) AT MT EMEI, CHINA

In five groups of seasonally provisioned Tibetan macaques (Macaca thibetana) at Mt. Emei, males were sampled for wounds as an indicator of their competition for females during about 80 days in the 1987 mating season. Quantitative data on intergroup transfer were collected in a period between June 1986 and December 1987. The young adult (YA) males, the most active age-class in mating activity and intergroup transfer, received most of the wounds. Wounds tended to appear more in the front of body for YA and subadults (SA) than they did for middle-old aged (MO) males. This implies that some of the MO males were more active and aggressive in the fights. During the 1.5 year period, 5/6 of the YA and 5/17 of the MO males made intergroup shifts. Although YA males faced a high risk of receiving wounds at transfer, they usually rose in rank. On the other hand, the MO males transferred more smoothly but dropped in rank. The peripheral SA males, which rarely emigrated in the population, were an active component in determining the wounding rate, and the rate and direction of male migration. Three SA immigrants died of severe attacks made by resident males in 1988 and 1991. Adult sex ratios and their variations were considerably reduced with male nonrandom shifts and better conservation of the population.

Detection of potential positive regulatory motifs of transcription in yeast introns by comparative analysis of oligonucleotide frequencies

We conducted a comparative statistical analysis of tetra- through hexanucleotide frequencies in two sets of introns of yeast genes. The first set consisted of introns of genes that have transcription rates higher than 30 mRNAs/h while the second set contained introns of genes whose transcription rates were lower than or equal to 10 mRNAs/h. Some oligonucleotides whose occurrence frequencies in the first set of introns are significantly higher than those in the second set of introns were detected. The frequencies of occurrence of most of these detected oligonucleotides are also significantly higher than those in the exons flanking the introns of the first set. Interestingly some of these detected oligonucleotides are the same as well known "signature" sequences of transcriptional regulatory elements. This could imply the existence of potential positive regulatory motifs of transcription in yeast introns. (C) 2003 Elsevier Ltd. All rights reserved.

The role of cell-surface-bound phosphatases in species competition within natural phytoplankton assemblage: an in situ experiment

Despite it is widely acknowledged that the ability to hydrolyze dissolved organic matter using extracellular phosphatases is diverse in fresh water phytoplankton, the competition within single species related to presence and quantity of cell-surface-bound phosphatases has not been examined in natural conditions yet. Here, we studied phytoplankton species competition in a freshwater reservoir during an in situ experiment. A natural plankton community, with the exclusion of large zooplankton, was enclosed in permeable dialysis bags inside two large containers of different bioavailable phosphate concentrations. Phytoplankton species biomass and the abundance of bacteria were determined in purpose to compare the development of enclosed microbial communities. Total and cell-surface-bound phosphatase activities in the phytoplankton were investigated using the Fluorescently Labelled Enzyme Activity (FLEA) technique that allows for direct microscopic detection of phosphatase-positive cells and, with image cytometry, enables quantification of phosphatase hydrolytic capacity. Production of extracellular phosphatases was not completely inhibited or stopped in the phosphate-enriched environment, phytoplankton cells only showed the activity less often. Under the phosphate-nonenriched conditions, the production of phosphatases was enhanced, but active species did not proliferate amongst phytoplankton assemblage. Further, specific growth rates of the phosphatase-positive species in the non-enriched environment were lower than the same phosphatase-positive species in phosphate-enriched environment. Interestingly, the phosphatase-positive cells of Ankyra ancora increased their size in both treatments equally, although the population in phosphate-enriched environment grew much faster and the cell-specific phosphatase activity was lower. We hypothesize that brand new daughter cells had sufficient phosphorus reserves and therefore did not employ extracellular phosphatases until they matured and needed extra bioavailable phosphorus to support their metabolism before cell division. Based on presented in situ experiment, we propose that the ability to hydrolyze organic polymers and particles with cell-surface-hound phosphatases is advantageous for longer persistence of given population in a phosphate-scarce environment; although phosphatase-positive species cannot dominate the reservoir phytoplankton solely because of specific phosphorus-scavenging strategy.

In situ study on effect of food competition on diet shifts and growth of silver and bighead carps in large biomanipulation fish pens in Meiliang Bay, Lake Taihu

Silver and bighead carps were cultured in large fish pens to reduce the risks of cyanobacterial bloom outbreaks in Meiliang Bay, Lake Tauhu in 2004 and 2005. Diet compositions and growth rates of the carps were studied from April to November each year. Both carp species fed mainly on zooplankton (> 50% in diet) in 2004 when competition was low, but selected more phytoplankton in 2005 when competition was high. Silver carp had a broader diet breadth than did bighead carp. Higher densities and fewer food resources increased diet breadths but decreased the diet overlap in both types of carps. It can be predicted that silver and bighead carps would be released from diet competition and shift to feed mainly on zooplankton at low densities, decreasing the efficiency of controlling cyanobacterial blooms. Conclusively, when silver and bighead carps are used to control cyanobacterial blooms, a sufficiently high stocking density is very important for a successful practice.

Gene structures and promoter characteristics of interferon regulatory factor 1 (IRF-1), IRF-2 and IRF-7 from snakehead Channa argus

Three interferon regulatory factor (IRF) genes, CaIRF-1, CaIRF-2 and CaIRF-7, and their promoters of snakehead (Channa argus) were cloned and characterized. The CaIRF-1 gene consists of ten exons, spans 4.3 kb and encodes a putative peptide of 299 aa. The CaIRF-2 gene consists of nine exons, spans 8 kb and encodes a putative peptide of 328 aa. The gene organizations of CaIRF-1 and CaIRF-2 are very similar to that of human IRF-1 and IRF-2 except more compact. Comparison of exon-intron organization of the two genes indicated a common evolutionary structure, notably within the exons encoding the DNA binding domain (DBD) of the two factors. The CaIRF-7 gene spans 4.1 kb and encodes a putative peptide of 437 aa. However, the gene organization of CaIRF-7 consisting of ten exons is different to human IRF-7a gene which has an intron in 5' UTR. Three CaIRFs share homology in N-terminal encompassing the DBD that contains a characteristic repeat of tryptophan residues. The promoters of CaIRF-1 and CaIRF-2 genes contain the conserved sites for NF-kappa B and Sp1. The gamma-IFN activation sites (GAS) were found in the promoters of CaIRF-1 and CaIRF-7. The promoter of CaIRF-7 contains conserved interferon stimulating response element (ISRE) which is characteristic of IFN-induced gene promoter, and suggests that there also exist intracellular amplifier circuit in fish IFN signal pathway. Moreover, the element GAAANN oriented in both directions is repeated in CaIRF promoter regions, which confers to further inducibility by IFN. The constitutive expression of CaIRF genes were found to increase obviously in response to induction by the known IFN-inducer poly I:C. (c) 2008 Published by Elsevier Ltd.

Molecular characterization and subcellular localization of Carassius auratus interferon regulatory factor-1

Interferon (IFN)-regulatory transcription factor-1 (IRF-1) has been studied in mammals and fish but little is known about the relationship between its gene structure and nuclear 'ion of IRF-1 protein. In this study, a cDNA encoding Carassius auratus IRF-1 (CaIRF-1) was isolated from an interferon-producing cell line, C. ouratus blastulae embryonic (CAB) cells, exposed to UV-inactivated grass carp hemorrhagic virus (GCHV). The CaIRF-1 genomic locus exhibits exon-intron arrangements similar to those of other vertebrate IRF-1 loci, with nine exons and eight introns, although together with pufferfish IRF-1, CaIRF-1 distinguishes itself from other vertebrate IRF-1 genes by a relatively compact genomic size. Similar to the known IRF-1 genes, CaIRF-1 is ubiquitously expressed, and is upregulated in vitro and in vivo in response to virus, Poty I:C, or CAB INF-containing supernatant (ICS). Subcellular localization analysis confirms the nuclear distribution of CaIRF-1 protein, and reveals two nuclear localization signals (NILS), any one of which is sufficient for nuclear translocation of CaIRF-1. One NLS Locates to amino acids 117-146, and appears to be the structural and functional equivalent of the NLS in mammalian IRF-1. The second NLS (amino acids 73-115) is found within the DNA-binding domain (DBD) of CaIRF-1, and contains two regions rich in basic amino acids (''(KDKSINK101)-K-95" and ''(75)KTWKANFR(82)"). In comparison with mammalian IRF-1, in which the corresponding amino acid stretch does not seem to drive nuclear translocation, five conserved basic amino acids (K-75, K-78, R-82, K-95, and K-101) and one non-conserved basic amino acid (K-97) are present in this NLS from CaIRF-1. This observation suggests that K97 Of CaIRF-1 might be essential for the function of its second NLS, wherein the six basic aminoacids might cooperate to drive CaIRF-1 to the nucleus. Therefore, the current study has revealed a new nuclear localization motif in the DBD of a vertebrate IRF-1. (C) 2007 Elsevier Ltd. All rights reserved.

Upstream regulatory region of zebrafish lunatic fringe: Isolation and promoter analysis

Lunatic fringe (Lfng), one modulator of Notch signaling, plays an essential part in demarcation of tissues boundaries during animal early development, especially somitogenesis. To characterize the promoter of zebrafish 1fng and generate somite-specific transgenic zebrafish, we isolated the upstream regulatory region of zebrafish 1fng by blast search at the Ensembl genome database (http://www. ensembl.org) and analyzed the promoter activity using green fluorescent protein (GFP) as a reporter. Promoter activity assay in zebrafish shows that the 0.2-kb fragment containing GC-box, CAAT-box, and TATA-box can direct tissue-specific GFP expression, while the 0.4-kb and 1.2-kb fragments with further upstream sequence included drive GFP expression more efficiently. We produced 1fngEGFP-transgenic founders showing somite-specific expression of GFP and consequently generated a hemizygous 1fngEGFP-transgenic line. The eggs from 1fngEGFP-transgenic female zebrafish show strong GFP expression, which is consistent to the reverse-transcription polymerase chain reaction PCR (RT-PCR) detection of 1fng transcripts in the fertilized eggs. This reveals that zebrafish 1fng is a maternal factor existing in matured eggs, suggesting that fish somitogcnesis may be influenced by maternal factors.

Molecular cloning and characterization of crucian carp (Carassius auratus L.) interferon regulatory factor 7

Interferon (IFN) can induce an antiviral state via interferon-regulatory transcription factors (IRFs), which bind to and control genes directed by the interferon-stimulated response element (ISRE). Here we describe a fish IRF, termed CaIRF7, cloned from a subtractive cDNA library which is constructed with mRNAs obtained from crucian carp (Carassius auratus L.) blastulae embryonic (CAB) cells infected by UV-inactivated GCHV and mock-infected cells. CaIRF7 cDNA was found to be 1816 bp in length, with a 42 bp 5' UTR and a 508 bp 3' UTR. The open reading frame translates into 421 amino acids in which a DNA-binding domain (DBD) containing the repeated tryptophan motif and IRFs association domain have been identified. Like chicken GgIRF3, CaIRF7 was most similar to mammalian IRF7 with 27 to 30% identity overall and some 37% identity in their DBDs. A single transcript of 1.9 kb was detected in virally induced CAB cells by virtual Northern blotting. RT-PCR analysis revealed a wide tissue distribution of CaIRF7 constitutive expression, with detectable transcript in non-infected CAB cells and various tissues of healthy crucian carp. In addition, CaIRF7 expression was differentially increased by stimulation of the CAB cells with active GCHV, UV-inactivated GCHV or CAB IFN, indicating that the activation of CaIRF7 was directly regulated by IFN. (C) 2003 Published by Elsevier Ltd.

Competition between band gap and yellow luminescence in undoped GaN grown by MOVPE on sapphire substrate

Undoped GaN epilayer on c-face (0 0 0 1) sapphire substrate has been grown by metalorganic vapor-phase epitaxy (MOVPE) in a horizontal-type low-pressure two-channel reactor. Photoluminescence (PL) as a function of temperature and excitation intensity have been systematically studied, and the competition between near band gap ultraviolet (UV) and defect-related yellow luminescence (YL) has been extensively investigated, It is revealed that the ratio of the UV-to-YL peak intensities depends strongly on the excitation intensity and the measurement temperature. The obtained results have been analyzed in comparison with the theoretical predications based on a bimolecular model. (C) 2001 Elsevier Science B.V. All rights reserved.