Effects of macrophage-colony-stimulating factor on cyclophosphamide-injected mouse NK1.1+ cell activity

 We injected cyclophosphamide into mice and examined their natural killer (NK) activity both in vitro and in vivo. Cyclophosphamide injection temporarily abrogated the lung clearance activity of Yac-1 lymphoma cells, which is considered to be an index of NK activity in vivo. However, administration of recombinant human macrophage-colony-stimulating-factor (rhM-CSF) to cyclophosphamide-injected mice restored the lung clearance activity. To clarify whether the administration of rhM-CSF activated NK cells, we purified NK1.1⁺ cells from mice treated with cyclophosphamide and/or rhM-CSF and examined their functions (cytotoxicity, proliferation, and interferon γ production) in vitro. Cyclophosphamide injection decreased the number, but did not suppress the functions of NK1.1⁺ cells. The numbers of NK1.1⁺ cells in cyclophosphamide-injected mice restored by rhM-CSF administration. And the functions of NK1.1⁺ cells from both saline-injected and cyclophosphamide-injected mice were accelerated by rhM-CSF administration. These results suggested that the temporary abrogation of NK activity in vivo caused by cyclophosphamide injection was due to a decrease in the number and not to suppression of the functions of NK1.1⁺ cells. The injection of cyclophosphamide into mice increased the number of tumor (B16 melanoma) nodules formed in the lungs and liver. However, treatment with rhM-CSF recovered the anti-metastatic activity in the lungs of cyclophosphamide-injected mice. These results show that administration of rhM-CSF restores NK activity suppressed by cyclophosphamide injection in vivo. Received: 28 September 1999 / Accepted: 23 December 1999     

Chiasmata and chromosome breakages are related to crossing over in Drosophila ananassae males.

A cytogenetic analysis of male crossing over in Drosophila ananassae revealed that cytological exchanges resulted in genetic crossing over, and that chiasma frequency and the genetic recombination correlated positively in chromosomes 2 and 3. Furthermore, the frequency of chromosome breakages correlated positively with chiasma frequency. Paracentric inversion heterozygosity had no detectable influence on the chromosome pairing or exchange events within the inversion loop at meiosis. Scoring of the chiasma demonstrated that males homozygous for the previously mapped enhancers of male crossing over had low frequencies of chiasmata, whereas higher frequencies of chiasmata were observed in males heterozygous for enhancers. The results presented here indicate that the genetic factors controlling male crossing over are involved in the origin of chromosome breakages and in exchange events.     

Interactions of 5-(1-Pyrenyl)-10,15,20-tris(4-methylpyridinium)porphine with Double-Helix and Triple-Helix Nucleic Acids

Abstract

5-(1 -Pyrenyl)-10,15,20-tris(4-methylpyridinium)porphine (H₂PTMPP) having a porphyrin ring and a pyrenyl substituent was synthesized. The compound H₂PTMPP bound to poly(dA)?poly(dT) double helix and poly(dA)?2poly(dT) triple helix in different styles. The results of H₂PTMPP binding to oligonucleotides, dA₁₄?dT₁₄ and dA₁₄?2dT₁₄, was also shown.

     

A calmodulin-binding mitogen-activated protein kinase phosphatase is induced by wounding and regulates the activities of stress-related mitogen-activated protein kinases in rice

The mitogen-activated protein kinase (MAPK) phosphatases (MKPs) are negative regulators of MAPKs. In dicotyledons such as Arabidopsis and tobacco, MKPs have been shown to play pivotal roles in abiotic stress responses, hormone responses and microtubule organization. However, little is known about the role of MKPs in monocotyledons such as rice. Database searches identified five putative MKPs in rice. We investigated their expression in response to wounding, and found that the expression of OsMKP1 is rapidly induced by wounding. In this study, we functionally characterized the involvement of OsMKP1 in wound responses. The deduced amino acid sequence of OsMKP1 shows strong similarity to Arabidopsis AtMKP1 and tobacco NtMKP1. Moreover, OsMKP1 bound calmodulin in a manner similar to NtMKP1. To determine the biological function of OsMKP1, we obtained osmkp1, a loss-of-function mutant, in which retrotransposon Tos17 was inserted in the second exon of OsMKP1. Unlike the Arabidopsis atmkp1 loss-of-function mutant, which shows no abnormal phenotype without stimuli, osmkp1 showed a semi-dwarf phenotype. Exogenous supply of neither gibberellin nor brassinosteroid complemented the semi-dwarf phenotype of osmkp1. Activities of two stress-responsive MAPKs, OsMPK3 and OsMPK6, in osmkp1 were higher than those in the wild type both before and after wounding. Microarray analysis identified 13 up-regulated and eight down-regulated genes in osmkp1. Among the up-regulated genes, the expression of five genes showed clear responses to wounding, indicating that wound responses are constitutively activated in osmkp1. These results suggest that OsMKP1 is involved in the negative regulation of rice wound responses.     

Search for species-specific mating signal in courtship songs of sympatric sibling species,Drosophila ananassae and D. pallidosa

Sexual isolation is one of the most important mechanisms that may lead to speciation. Drosophila ananassae and D. pallidosa are useful for the study of sexual isolation, because of their sympatric distribution and no postmating isolation between them. Courtship songs are considered to play a crucial role in sexual isolation between D. ananassae and D. pallidosa. We recorded and analyzed male courtship songs of D. ananassae and D. pallidosa for eight and four geographical strains, respectively. Courtship behaviors of the two species were consistent with those previously described, however, male's middle leg shaking, which had not before been described, was observed in both species. Males sing by wing vibration only during courtship. Their song oscillograms were distinct between species, but those of conspecific strains were very similar, in spite of their different geographical derivation. We found species-specificity in burst length, pulse length, cycle number in a pulse, and frequency spectra of bursts; these results suggest that these song parameters may play a role in mate recognition that enforces their sexual isolation. The specific values of interpulse interval, cycle number in a pulse and intrapulse frequency were involved with the determination of specificity in frequency spectra of bursts. We discussed the possibility that the specific frequency spectra of bursts are recognized by females as the species-specific signal rather than each parameter individually.     

Antimetastatic effect of recombinant human macrophage-colony-stimulating factor against lung and liver metastatic B16 melanoma

 We studied the effect of recombinant human macrophage-colony-stimulating factor (rhM-CSF) on the formation of lung and liver metastases following the i.v. injection of the B16 melanoma subline (B16 LiLu) into mice. When rhM-CSF was administered before the B16 inoculation, the number of tumor metastases decreased in the lung and liver. However, the administration of rhM-CSF after B16 inoculation did not produce an antimetastatic effect in the lung, but did in the liver. B16 cells labeled with 5-[¹²⁵I]-iodo-2′-deoxyuridine (¹²⁵I-dUrd) were injected and the arrest of tumor cell emboli was examined in the capillary beds of the lung and liver of mice treated with either vehicle or rhM-CSF. In both groups, there were the same numbers of B16 cells in both the lung and the liver 3 minutes after the B16 injection, and almost all tumor cells died within 24 h. However, the number of cells surviving in the lung was decreased in mice injected with rhM-CSF (37%). There was no difference in the number of cells in the livers of mice treated either with vehicle or rhM-CSF in the first 24 h after tumor cell injection. The administration of rhM-CSF increased NK 1.1⁺ cells in the mouse spleen and facilitated NK activity in vivo. At the same time, the administration of an anti-NK 1.1 antibody blocked the antimetastatic effect of rhM-CSF in the lung but not in the liver. The antibody was effective only when it was injected before the B16 inoculation. These results suggest that the antimetastatic effect of rhM-CSF in the lung was mediated by NK 1.1⁺ cells within 24 h of B16 injection. In contrast, the antimetastatic effect of rhM-CSF in the liver was mediated not only by NK 1.1⁺ cells but also by other antimetastatic systems such as macrophages. Received: 8 April 1996 / Accepted: 26 November 1996     

Determination of RAPD Markers in Rice and their Conversion into Sequence Tagged Sites (STSs) and STS-Specific Primers

We produced 102 randomly amplified polymorphic DNA (RAPD) markersmapped on all 12 chromosomes of rice using DNAs of cultivarsNipponbare (japonica) and Kasalath (indica) and of F2 populationgenerated by a single cross of these parents. Sixty random primers10 nucleotides long were used both singly and in random pairsand about 1,400 primer-pairs were tested. Using both agarosegel and polyacrylamide gel electrophoresis enabled us to detectpolymorphisms appearing in the range from <100 bp to 2 kb.The loci of the RAPD markers were determined onto the frameworkof our RFLP linkage map and some of these markers were mappedto regions with few markers. Out of the 102 RAPD markers, 20STSs (sequence-tagged sites) and STS-specific primer pairs weredetermined by cloning, identifying and sequencing of the mappedpolymorphic fragments.