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1.
Stable carbon isotopes in tree rings of beech: climatic versus site-related influences 总被引:11,自引:0,他引:11
M. Saurer Silvio Borella Fritz Schweingruber Rolf Siegwolf 《Trees - Structure and Function》1997,11(5):291-297
Stable carbon isotopes in tree rings are a promising tool in palaeoclimate research, provided attempts are made to disentangle
climatic from local effects (e.g. soil properties, competition, light). The 13C/12C variations in cellulose of tree rings of beech (Fagus sylvatica) were determined at several sites in the Swiss Central Plateau covering the last 50 years. We chose sites which differ in
moisture conditions and sampled cores from four to six trees per site. The mean 13C/12C series from the different dry sites (distant by up to 40 km) are closely interrelated suggesting a common external cause.
Correlation analysis with climate data proved the total precipitation in the months May, June and July to have the strongest
effect on the carbon isotopes (r = – 0.73). This result is in agreement with the commonly used model which relates the isotope discrimination to the water
use efficiency. On the other hand, the isotope series of the wet sites are not as well correlated to the climate. At two of
the sites (a dry and a humid) tree ring width suddenly increased. We used this effect as a test-case to study the influence
of local growth conditions on the climate-isotope relationship.
Received: 17 April 1996 / Accepted: 2 September 1996 相似文献
2.
Induction of accessory cell function of human alveolar macrophages by inhalation of human natural interleukin-2 总被引:1,自引:0,他引:1
Gernot Zissel Walter E. Aulitzky J. Lorenz Christoph Huber J. Müller-Quernheim 《Cancer immunology, immunotherapy : CII》1996,42(2):122-126
Accessory function allows antigen-presenting cells to produce sufficient secondary signals for optimum T cell proliferation
and interleukin-2 (IL-2) production. Alveolar macrophages are inferior accessory cells compared to monocytes (PBM). We report
here that the accessory index (AI) of alveolar macrophages and PBM of patients with lung metastases of solid tumors treated
with inhalations of human natural IL-2 (hnIL-2) increased following its administration (P<0.005). The accessory index was significantly elevated from baseline values after 2 weeks of inhalation of 300 000 IU hnIL-2/day
(8.2±10.2 compared to 1.1±1; P<0.001). The inhalation of 150 000 IU also induced increases in the index (AI = 2.3±1.9), however, without reaching statistical
significance. In addition at 300 000 IU IL-2/day a significant increase in the accessory index was observed for PBM (4±2.5;
P<0.05). The indices of PBM and alveolar macrophages prior to inhalation showed a significant negative correlation with the
age of the patients (r
s = – 0.5; r
s = – 0.8, respectively; P<0.03 for all comparisons). Our data demonstrate that the inhalational application of hnIL-2 enhances the accessory function
of alveolar macrophages and, to lesser extent, the accessory index of PBM, indicating the occurrence of pharmacological immunostimulation.
Received: 16 August 1995 / Accepted: 4 January 1996 相似文献
3.
Tsukasa Sato Yasuhiko Midorikawa Takao Yamashita Akemi Araki F. Sendo 《Cancer immunology, immunotherapy : CII》1996,43(2):77-86
Effective treatment of a rat transplanted ascites tumor by i. p. injection of a streptococcal biological response modifier,
OK-432, was abrogated by selective in vivo depletion of neutrophils by a monoclonal antibody, RP-3. The mechanisms by which
neutrophils participate in the therapeutic action of OK-432 were studied with Winn’s assay using peritoneal exudate cells
periodically obtained from rats i. p. injected with this biological response modifier. Intraperitoneal resident macrophages
were first activated with OK-432, and within 3 h, tumor-inhibitory activity had moved to the early exuded neutrophils. However,
6 h after injection, exuded macrophages were the only cells involved in tumor inhibition. Considered together with other findings,
it is likely that, in this system, neutrophils may transmit information from resident macrophages to exuded inflammatory macrophages
in a series of responses induced by i. p. injection of OK-432.
Received: 29 April 1996 / Accepted: 27 July 1996 相似文献
4.
Class I major histocompatibility complex (Mhc) cDNA clones were isolated from axolotl mRNA by polymerase chain reaction (PCR) and by screening a cDNA phage library. The
nucleotide and predicted amino acid sequences show definite similarities to the Mhc class Iα molecules of higher vertebrates.
Most of the amino acids in the peptide binding region that dock peptides at their N and C termini in mammals are conserved.
Several amino acids considered to be important for the interaction of β2-microglobulin with the Mhc α chain are also conserved in the axolotl sequence. The fact that axolotl class I A cDNAs are
ubiquitously expressed and highly polymorphic in the α1 and α2 domains suggests the classical nature of axolotl class I A
genes.
Received: 3 June 1996 / Revised: 14 October 1996 相似文献
5.
Kiyoshi Asai Haruki Kato Shigeru Kimura Shigehiko Mukai Yutaka Kawahito Hajime Sano Motoharu Kondo Keiko Akaogi K. Hirose 《Cancer immunology, immunotherapy : CII》1996,42(5):275-279
We have elucidated the direct effects of PSK (a protein-bound polysaccharide) and OK-432 (a streptococcal preparation), both
immunomodulating drugs, on the gene expression for an inducible nitric oxide synthase and on the production of nitric oxide
(NO) in the RAW264.7 murine macrophage cell line. As determined by northern blot analysis, both immunomodulating drugs were
potent inducers of gene expression for inducible NO synthase when cells were costimulated with interferon-γ (IFNγ). Expression
of mRNA for the enzyme occurred in a dose-dependent manner after 3 h, when 10 – 50 μg/ml PSK or 0.001 – 1 KE/ml OK-432 was
used. Furthermore, NO was also produced in response to these drugs, as detected by the Griess reagent reaction. The enhancement
of NO synthesis was thought to be mediated, in part, through tumor necrosis factor α (TNFα) induction by these agents, since
a neutralizing antibody to TNFα significantly suppressed NO production in RAW264.7 cells stimulated with PSK or OK432 in combination
with IFNγ. We speculate that NO production may play a role in tumoricidal and microbicidal activities of PSK or OK-432 in
vivo.
Received: 9 August 1995 / Accepted: 1 April 1996 相似文献
6.
The plant cytoskeleton has been implicated in a variety of morphogenetic events in higher plants. Most of this work, however,
has concentrated on epidermal cells or primary tissues. We have investigated the cortical microtubular (CMT) and microfilament
(MF) components of the cytoskeleton in a secondary tissue – active vascular cambium of Aesculus hippocastanum L. (horse-chestnut) – and followed the changes in these components during the early stages of differentiation of fusiform
cambial derivatives to axial elements of the secondary vascular system. A correlative approach was used employing indirect
immunofluorescence microscopy of α-tubulin on 6 μm sections, and transmission electron microscopy of 60 nm sections. The study
has demonstrated a rearrangement of the CMT cytoskeleton, from random to helical, as fusiform vascular cambial cells begin
to differentiate as secondary phloem vascular tissue. A similar CMT rearrangement is seen as fusiform cambial cells begin
to differentiate as secondary xylem fibres. This rearrangement is interpreted as evidence of determination of cambial derivatives
towards vascular development. Axially-oriented MF bundles are present in fusiform cambial cells and their axial orientation
is retained in the vascular derivatives at early stages of their development even though the CMTs have become rearranged.
Received: 5 August 1996 / Accepted: 23 September 1996 相似文献
7.
Alan B. Darlington Anna Halinska James F. Dat T. J. Blake 《Trees - Structure and Function》1997,11(4):223-228
Plant responses to saturation vapour pressure deficit (SVPD) were studied by subjecting black spruce [Picea mariana (Mill) B.S.P.] and jack pine seedlings (Pinus banksiana Lamb.) to humid (0.3 – 0.8 kPa) or dry (2.0 – 2.5 kPa SVPD) regimes for 4 weeks using a computer-controlled environmental
system to control diurnal variation in SVPD. Dry matter accumulation in needles was not altered by increasing SVPD. However,
root growth declined by 60% which increased shoot to root ratio and reduced total seedling dry weight in both black spruce
and jack pine. Relative growth rate of jack pine also declined to about half the rate of plants grown under humid conditions.
In situ root marking studies showed that the decline in root growth of jack pine under the high SVPD was the result of reduced
lateral root initiation, whereas root elongation was unaffected by humidity. A 4-week exposure to dry air increased abscisic
acid (ABA) levels in needles, but not roots, of jack pine whereas ABA levels in black spruce were not altered. A short (3-day)
exposure failed to increase needle ABA levels in either species. These results suggest that the responses of conifers to dry
air were not the result of ABA accumulation.
Received: 24 March 1996 / Accepted: 30 May 1996 相似文献
8.
Hiroya Kobayashi Taku Kokubo Yusuke Abe Keisuke Sato Shoji Kimura Naoyuki Miyokawa Makoto Katagiri 《Immunogenetics》1996,44(5):366-371
The peptide motif of the HLA-DR53 (DRB4*0101) molecule, which is associated with autoimmune diseases including Vogt-Koyanagi-Harada’s syndrome, was determined by
peptide binding assay using human L plastin p581 – 595 peptide and its substituted analogues. L plastin p581 – 595 peptide
is one of the naturally processed peptides bound to HLA-DR9/DR53 (DRB1*0901/DRB4*0101) molecules. The binding affinity of each peptide to the HLA-DR53 molecule was measured by fluorescence intensity of biotinylated
peptides to L cell transfectants expressing HLA-DR53 molecules, followed by treatment with avidin-fluorescence. Binding of
biotinylated peptides to HLA-DR53 molecules was not inhibited by all single-alanine-substituted nonbiotinylated peptides,
indicating that the replaced position was important for binding to the HLA-DR53 moleule. The inhibitory motif is considered
to be an HLA-DR53-specific binding motif, composed of a positively charged residue (K) at position 1, a hydrophobic residue
(I) at position 4, positively charged residue (R or K) at position 8 or 9, and another hydrophobic residue (I) at position
10. This predicted motif is different from the binding motifs of other HLA-DR molecules.
Received: 29 April 1996 / Revised: 16 June 1996 相似文献
9.
Morphology and ecological significance of intra-annual radial cracks in living conifers 总被引:3,自引:0,他引:3
P. Cherubini Fritz Hans Schweingruber Theodor Forster 《Trees - Structure and Function》1997,11(4):216-222
Intra-annual radial cracks were studied on 294 cross-sections of Norway spruce sampled at two forest sites in the eastern
Alps (Italy) and from seven isolated trees in the Jura region (Switzerland). Cracks were occasionally accompanied by traumatic
resin canals in the wood that was formed after the cracking. Most of the cracks, however, were without such canals. Traumatic
resin canals are not significantly more abundant in tree rings formed after cracking, and their occurrence is not related
to the cracking. Cracks developed when the cambium was inactive. Water imbalances during the early spring, due to transpiration
losses and inadequate moisture supply from very cold roots, are the likely cause of these cracks.
Received: 21 February 1996 / Accepted: 14 June 1996 相似文献
10.
11.
Keith R. Jerome Allan D. Kirk Gabriele Pecher Wayne W. Ferguson O. J. Finn 《Cancer immunology, immunotherapy : CII》1997,43(6):355-360
The human mucin, MUC-1, is a transmembrane glycoprotein that is produced by both normal an malignant epithelium. The MUC-1
produced by malignant epithelium is underglycosylated, which leads to the expression by tumors of novel T and B cell epitopes
on the mucin polypeptide core. Similar underglycosylation occurs in the lactating breast. In this report, we describe a long-term
survivor of breast cancer whose tumor strongly expressed the T- and B-cell-stimulatory epitopes. Five years after presenting
with the tumor, the patient had her first pregnancy, at which time she developed fulminant lymphocytic mastitis. We demonstrate
that the lactating breast produced mucin expressing the same “tumor-specific” epitopes as the original cancer. The patient
had circulating anti-mucin antibodies of both the IgM and IgG isotypes (these are not found in normal controls), and mucin-specific
cytotoxic T lymphocytes in the peripheral blood. Limiting – dilution analysis for mucin – specific cytotoxic T lymphocytes
in three different experiments yielded frequencies of 1 in 3086, 1 in 673, and 1 in 583, compared to approximately 1 in 106 in normal controls. The patient remains clinically free of carcinoma after 5 additional years of follow-up. We propose that
the original tumor primed the patient’s immune response against the mucin epitopes, and that the re-expression of these epitopes
on the lactating breast evoked a secondary immune response. It is tempting to speculate that the vigor of her anti-mucin immunity
may have helped protect this patient against recurrent tumor.
Received: 12 February 1996 / Accepted: 5 November 1996 相似文献
12.
呼伦贝尔沙地樟子松年轮生长对气候变化的响应 总被引:2,自引:0,他引:2
以内蒙古呼伦贝尔地区沙地樟子松为样本,建立了樟子松树木年轮宽度年表,应用相关分析和响应函数分析等年轮气候学方法,研究了樟子松径向生长对气候变化的响应。结果表明,樟子松年轮宽度与4月和6—9月平均温度呈显著负相关关系(P<0.05);与各月降水量多呈正相关关系,特别是与当年5—8月的月降水量呈显著正相关关系(P<0.05);树轮年表与前一年10月至当年10月的PDSI均呈显著正相关关系(P<0.05),其中与5月份PDSI的相关性最高。响应函数分析表明,年表与当年6—7月的平均气温、上一年10月和当年5—7月份的降雨存在显著的相关性,与5—7月份PDSI存在较显著的正相关性;综合来看,呼伦贝尔沙地樟子松生长同时受降水和温度的影响,其径向生长与气候因子间的关系属于降水敏感型,为区域降水重建提供了科学基础。 相似文献
13.
The effect of global warming on alpine forests is complex. It is crucial, therefore, to investigate the effects of climate change on the radial growth of trees at different altitudes. The tree growth–climate relationship remains poorly understood at large spatial scales in the Tianshan Mountains, China. Schrenk spruce (P. schrenkiana) is a unique tree species to this area. In this study, we collected tree-ring width and maximum density data from nine plots along an altitudinal gradient. Results showed that altitude affected both tree-ring width and maximum density. At high altitudes, tree-ring width was positively correlated with temperature in February of the current year. Tree-ring width was also positively correlated with precipitation in July of the previous year, and January and July of the current year, and negatively correlated with the monthly diurnal temperature range (DTR). At low altitudes, tree-ring width was negatively correlated with temperature in the early growing season and the growing season. Tree-ring width was positively correlated with precipitation in June and September of the previous year, and May of the current year. The tree-ring maximum density was positively correlated with temperature and the DTR of the growing season, and negatively correlated with precipitation in winter and growing season. Moving correlation analysis showed that the positive response of tree-ring width to precipitation in the growing season was enhanced over time at high altitudes. In the low-altitude trees, the negative response of tree-ring width to temperature in the growing season was reduced, while the positive response to precipitation in the growing season was enhanced. The positive response relationship between tree-ring maximum density and the temperature in July weakened over time. At low altitudes, the negative response of tree-ring maximum density to winter precipitation was strengthened, and a stable negative response to July precipitation was observed. As the climate becomes wetter and warmer in the Tianshan Mountains, our results suggest that the radial growth of trees may benefit at elevations above 2400 m a.s.l. There was no obvious elevation limit for the increase in tree-ring maximum density. These findings provide a basis for sustainable forest management under global climate change. 相似文献
14.
An improved strain of Pseudomonas sp. ATCC 31461 (Pseudomonas elodea), capable of producing broth viscosities of 11 000 and 4700 mPa s (cP) when grown in enriched whey permeate and enriched
sweet whey broths respectively, was isolated. The isolation was by serial transfers of the parent on lactose-rich and sweet
whey broths. Maximum viscosities and biopolymer production were observed in 25% (v/v) whey concentration. In whey concentrations
of 50% (v/v) or greater, residual glucose was detected in the broth and biopolymer production was low. This strain is capable
of totally utilising the lactose in up to 50% (v/v) whey in 64 h. Enzyme activities suggest that the transport of lactose
in P. elodea is by the permease system as opposed to the phosphotransferase system. The location of β-galactosidase is mainly intracellular.
The improved strain is able to utilise lactose better than the parent and produce 1.6 times more intracellular β-galactosidase
activity compared to the parent.
Received: 3 May 1996 / Received revision: 8 August 1996 / Accepted: 10 August 1996 相似文献
15.
Philip O. Livingston Shengle Zhang Kenneth O. Lloyd 《Cancer immunology, immunotherapy : CII》1997,44(1):1-9
Resistance to chemotherapy is a major cause for failure in the treatment of lung cancer. Compared to conventional cytotoxic
drugs, immunotoxins act by different mechanisms and thus might be promising for the treatment of chemoresistant cancer. The
monoclonal antibody MOC31 recognises the epithelial glycoprotein-2 (EGP-2), a cell-surface antigen associated with small-cell
lung cancer (SCLC) and a major fraction of lung adenocarcinomas. An immunotoxin composed of MOC31 and a recombinant form of
Pseudomonas exotoxin A lacking the cell-binding domain (ETA252 – 613) was prepared, and its effect on lung cancer cell lines examined. MOC31-ETA252 – 613 was selectively cytotoxic to EGP-2-positive SCLC and adenocarcinoma cell lines inhibiting proliferation by 50% at concentrations
ranging from 0.01 nM to 0.3 nM. Moreover, the immunotoxin reduced the numberof clonogenic tumour cells from cultures by factors
of 104 and 105 during a 24-h and a 3-week exposure respectively. In athymic mice, the immunotoxin, which revealed a serum half-life of approximately
4 h, caused substantial regression of small (40 mm3) chemoresistant tumour xenografts and significantly delayed the growth of larger tumours (120 mm3). This finding indicates that MOC31-ETA252 – 613 may be useful for the treatment of lung cancer in the setting of chemoresistant minimal residual disease.
Received: 31 October 1996 / Accepted: 5 December 1996 相似文献
16.
A study was conducted to assess the dynamics of vesicular-arbuscular mycorrhizal (VAM) fungi associated with Acacia farnesiana and A. planifrons in moderately fertile alkaline soils. The intensity of root colonization by VAM fungi and the distribution of VAM fungal
structures varied with host species over a period of time. The occurrence of vesicles with varied morphology in the mycorrhizal
roots indicates infection by different VAM fungal species. This was further confirmed from the presence of spores belonging
to different VAM fungal species in the rhizosphere soils. Root colonization and spore number ranged from 56% – 72% and 5 – 14
g –
1soil in A. farnesiana and from 60% – 73% and 5 – 15 g –
1 soil in A. planifrons. Per cent root colonization and VAM spore number in the rhizosphere soil were inversely related to each other in both the
Acacia species. However, patterns of the occurrence of VAM fungal structures were erratic. Spores of Acaulospora foveata, Gigaspora albida, Glomus fasciculatum, G. geosporum and Sclerocystis sinuosa were isolated from the rhizosphere of A. farnesiana whereas A. scrobiculata,
G. pustulatum, G. fasciculatum,
G. geosporum and G. microcarpum were isolated from that of A. planifrons. The response of VAM status to fluctuating edaphic factors varied with host species. In A. farnesiana though soil nitrogen (N) was positively correlated with root colonization, soil moisture, potassium and air temperature were
negatively correlated to both root colonization and spore number. Per cent root colonization and spore number in A. planifrons were negatively related to each other. Further, in A. planifrons as the soil phosphorus and N were negatively correlated with the density of VAM fungal spores, the same edaphic factors along
with soil moisture negatively influenced root colonization.
Received: 16 May 1995 / Accepted: 7 February 1996 相似文献
17.
P. Becker Azman Asmat Julaihi Mohamad Misli Moksin Melvin T. Tyree 《Trees - Structure and Function》1997,11(7):432-435
In contrast with previous reports, we observed high transpiration rates in mangrove trees. Maximum sap velocities and mean
daytime sap flow rates were estimated from heat pulse velocity in entire, field grown trees of Avicennia cf. alba Blume and Rhizophora apiculata Blume. Results were within the range of values measured by identical techniques for trees in lowland dipterocarp and tropical
heath forests with a similar climate in Brunei Darussalam (north Borneo). High stomatal conductance (400 mmol m –
2 s –
1) was also measured for well insolated leaves of A. cf. alba, with midday water potentials reaching about – 3 MPa in both species.
Received: 11 September 1996 / Accepted: 27 January 1997 相似文献
18.
19.
C. Schönbach Kiyoshi Miwa Masaaki Ibe Hajime Shiga Kiyoshi Nokihara Masafumi Takiguchi 《Immunogenetics》1996,45(2):121-129
HLA-B*3501 is associated with subacute thyroiditis and fast progression of AIDS. An important prerequisite to investigate the T-cell
recognition of HLA-B*3501-restricted antigens is the characterization of peptide-HLA-B*3501 interactions. In this study, peptide-HLA-B*3501 interactions were determined in quantitative peptide binding assays. The results were statistically analyzed to evaluate
the influence of both anchor and nonanchor positions and the predictability of peptide binding. The binding data demonstrated
that all anchor residues at position 2 and the C-terminus found in 9-mers functioned equally as anchors in 10-mers and 11-mers.
These minimum requirements of peptide binding were refined by assessing positive and negative effects of nonanchor residues.
Aliphatic hydrophobic residues at positions 3, 5, and 8 of 10-mers and position 3 of 11-mers significantly enhanced HLA-B*3501 binding. Similar effects rendered aromatic, bulky residues, acidic or polar residues of 11-mers at position 1 as well
as at positions 4, 8, and 10, respectively. Negative effects were observed for residues carrying positively charged side-chains
at position 7 of 11-mers. The refined HLA-B*3501 peptide binding motifs enhanced the identification of potential T-cell epitopes. The disparity between positive effects
at the middle and C-terminal part (positions 5 – 8 and 10) of 11-mers and shorter peptides supports the extrusion of 11-mer
residues at positions 5, 6, and 7, away from the HLA-B*3501 binding cleft.
Received: 29 May 1996 / Revised: 5 August 1996 相似文献
20.
F. Konishi Masao Mitsuyama Masao Okuda Kuniaki Tanaka Takashi Hasegawa Kikuo Nomoto 《Cancer immunology, immunotherapy : CII》1996,42(5):268-274
An acidic glycoprotein prepared from a culture of Chlorella vulgaris (CVS) was examined for its protective effect on 5-fluorouracil(5FU)-induced myelosuppression and indigenous infection in
mice. Subcutaneous administration of CVS greatly reduced the mortality of non-tumor-bearing mice given a high dose of 5FU,
and could increase the LD50 value of 5FU for these mice. After 5FU treatment, indigenous infection developed probably as a result of the impairment of
the host defense system. CVS reduced the incidence of indigenous infections and this effect was attributable to the acceleration
of recovery from 5FU-induced myelosuppression. Early recovery of hematopoietic stem cells, or cells responding to interleukin-3
or granulocyte/macrophage-colony-stimulating factor, was especially observed in the bone marrow of CVS-treated mice on days
4 – 9 after the injection of 5FU. When tumor-bearing mice were given CVS during treatment with 5FU, CVS prolonged the survival
of mice without affecting the antitumor activity of 5FU. In addition, CVS was itself shown to exert an antitumor effect. These
results suggested that CVS may be beneficial for the alleviation of side-effects in cancer chemotherapy without affecting
the antitumor activity of the chemotherapeutic agent.
Received: 15 August 1995 / Accepted: 23 April 1996 相似文献