中国陆地生态系统对全球变化的敏感性研究

根据自然植被净第一性生产力综合模型和农业净第一性生产力模型计算了我国自然植被及农作物的净第一性生产力,结果表明:在所有可能的气候条件下,我国陆地生态系统的生产力表现出由东南向西北递减的趋势及明显的条带状分布,并在新疆地区形成明显的低值区。在年平均气温升高2℃且降水不变的情况下,湿润地区生产力增加幅度最大,约增加1～2tDW·hm~(-2)·a~(-1);在年平均气温升高2℃、年降水增加20％的情况下,干旱、半干旱地区生产力增加幅度最大,约增加0.5～3.0tDW·hm~(-2)·a~(-1);在年平均气温升高2℃、年降水减少20％的情况下,湿润地区生产力提高约0.5～1.0tDW·hm~(-2)·a~(-1),干旱、半干旱地区生产力降低约0.5～2.0tDW·hm~(-2)·a~(-1)。     

INCREASED SENSITIVITY TO LIGHT-INDUCED MELATONIN SUPPRESSION IN PREMENSTRUAL DYSPHORIC DISORDER

Increased sensitivity to light-induced melatonin suppression characterizes some, but not all, patients with bipolar illness or seasonal affective disorder. The aim of this study was to test the hypothesis that patients with premenstrual dysphoric disorder (PMDD), categorized as a depressive disorder in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), have altered sensitivity to 200 lux light during mid-follicular (MF) and late-luteal (LL) menstrual cycle phases compared with normal control (NC) women. As an extension of a pilot study in which the authors administered 500 lux to 8 PMDD and 5 NC subjects, in the present study the authors administered 200 lux to 10 PMDD and 13 NC subjects during MF and LL menstrual cycle phases. Subjects were admitted to the General Clinical Research Center (GCRC) in dim light (<50 lux) to dark (during sleep) conditions at 16:00?h where nurses inserted an intravenous catheter at 17:00?h and collected plasma samples for melatonin at 30-min intervals from 18:00 to 10:00?h, including between 00:00 and 01:00?h for baseline values, between 01:30 and 03:00?h during the 200 lux light exposure administered from 01:00 to 03:00?h, and at 03:30 and 04:00?h after the light exposure. Median % melatonin suppression was significantly greater in PMDD (30.8%) versus NC (?0.2%) women (p?=?.040), and was significantly greater in PMDD in the MF (30.8%) than in the LL (?0.15%) phase (p?=?.047). Additionally, in the LL (but not the MF) phase, % suppression after 200 lux light was significantly positively correlated with serum estradiol level (p ?=? .007) in PMDD patients, but not in NC subjects (p?>?.05). (Author correspondence: bparry@ucsd.edu)     

水稻品种超氧物歧化酶(SOD)活性与氧抑光合的关系

O_2抑光合程度不同的水稻品种,SOD活性存在差异。在40％O_2下,SOD活性被诱导增加水平高、延续时间长的品种,表现O_2抑光合程度小,反之则O_2抑光合程度大。在自然条件下,强光、高温都是诱导SOD活性变化的因素。选择SOD活性高、O_2抑光合程度小的种质资源可能有利于适应对光合不利的逆境条件。     

LIGHT HISTORY INFLUENCES THE SENSITIVITY TO ATRAZINE IN PERIPHYTIC ALGAE

This study examines the relationship between light history (i.e. light conditions during colonization) and sensitivity to atrazine for periphyton communities grown on etched glass substrates (colonized for 2–3 weeks) at seven stream and river sites differing in water chemistry and light regime. For each site, taxonomic composition of the community (by microscopic examination and cell counts), pigment composition, and photosynthetic parameters were measured and related to sensitivity to the herbicide. Photosynthetic parameters were estimated from photosynthesis– irradiance (P-I) curves; the responses of the algae to atrazine were analyzed using short-term concentration–response tests. Periphyton communities colonizing shaded sites were diatom dominated, had higher percentages of accessory pigments, and were more susceptible to photoinhibition at high light intensities compared to periphyton communities colonizing open sites; communities in the more open sites were dominated by green algae or cyanobacteria. Periphyton communities colonizing open sites were more sensitive to atrazine; the concentration of atrazine needed to inhibit photosynthesis by 50% in the short-term tests (EC₅₀ values) was correlated with light conditions during colonization. The interaction between treatment factors (light conditions during colonization, irradiance of incubation, and atrazine concentration) was analyzed by three-way ANOVA. The two-way interactions were significant, indicating that the response of the periphyton to irradiance during incubation and to atrazine concentration both depend on light history. However, the magnitude of the interaction between light history and atrazine toxicity was attenuated by changes in irradiance during incubation (three-way ANOVA). This investigation presents evidence that the apparent toxicity of atrazine to lotic periphyton in natural communities is greater for algae that are adapted to high-light conditions than for those that are adapted to low-light conditions.     

恶疫霉致病力和对甲霜灵敏感性的遗传与变异*

以分离自黑龙江腐烂苹果的恶疫霉Phytophthora cactorum Schroeter野生型菌株Ap14为亲本,采用菌丝块创伤接种法测定了恶疫霉对苹果的致病力在无性繁殖和有性生殖后代的遗传。结果是连续2代单游动孢子后代在苹果上所致病斑半径分别为22.4~24.1mm和21.8~23.4mm,与亲本所致病斑半径22.5mm无显著差异;而其20个自交后代个体所致病斑半径为21.4~25.8mm,与亲本有显著差异,其中2株致病力显著强于亲本,其余与亲本相似。表明恶疫霉对苹果的致病力在无性后代可稳定遗传,而在自交有性后代发生分离。同时在含甲霜灵0.05μg/ml的LBA平板上测定了恶疫霉菌丝生长对甲霜灵的敏感性在无性和有性后代的遗传。结果是恶疫霉对甲霜灵的敏感性在无性单孢后代无显著变异,而在50个自交有性后代中,上述浓度对其菌丝生长的抑制率分布范围为67.3~97.1%,与亲本78.3%有极显著差异,其中3株高于亲本,3株低于亲本,44株与亲本相似。表明恶疫霉对甲霜灵的敏感性同样在无性后代稳定遗传而在有性后代发生变异。上述结果提示,供试恶疫霉菌株中上述性状可能由细胞核杂合基因控制。     

乳腺肿瘤中抗酸菌L型感染的研究

用ＩＫ抗酸染色和卡介苗抗体免疫组化染色等方法对乳腺癌（９７例）,和乳腺纤维腺瘤（２１例）进行了研究。结果发现Ｌ型阳性例数在乳腺癌和乳腺纤维腺瘤间无显著差异（Ｐ〉０．０５）。乳腺癌中抗酸菌Ｌ型主要分布于癌细胞巢及其间质内,常集聚成堆,且该处癌细胞有不同程度变性或坏死。乳腺纤维腺瘤中的抗酸菌Ｌ型主要存在于间质巨噬细胞中。并讨论了抗酸菌Ｌ型感染与乳腺癌发生的可能关系。     

ATOPIC DERMATITIS DUE TO SENSITIVITY TO POLLEN

Observation of 100 patients with atopic dermatitis due to hypersensitivity to pollen over a period of 12 years emphasized certain important diagnostic and therapeutic features. The incidence was higher in females than in males and higher in middle and old age than in the earlier years.Pollen dermatitis may be the sole or major manifestation of allergy; 43 patients gave no history of other allergic symptoms. It may involve any or all areas of the body. The site or the distribution of lesions or the nature of the lesions gave no clue as to the diagnosis of pollen sensitivity.The character of the eruption varied widely from patient to patient and in given patients from week to week at times.Atopic dermatitis due to pollen sensitivity may be purely seasonal, perennial with seasonal exacerbations or perennial without seasonal variation.Reactions to skin testing with pollens suspected as allergens may be positive, equivocal or negative. In 58 patients there were positive correlative skin reactions to pollens.The diagnosis of atopic dermatitis due to pollen sensitivity, and the composition of the desensitizing antigen or antigens, must be based primarily on the clinical history and the area of residence.Most patients could tolerate only very weak dilutions at the beginning of desensitization therapy. Strong dilutions caused exacerbation of the dermatitis.Good or excellent results were obtained with perennial pollen desensitization therapy administered over long periods. In 13 patients good results took four to eight years of desensitization therapy. Fifty required less than two years. Tolerance of the patient for a given dose of antigen should determine the maximum dilution used in therapy.     

CUTANEOUS RIDGES IN ODONTOCETES

Cutaneous ridges are present at the surface of the skin in many odontocetes, and although often quite faint, may be observed with the naked eye. We have taken surface impressions and measured the ridges of individuals of seven odontocete species, and observed cutaneous ridges on three additional species. In the delphinids and the one Physeter neonate studied, spatial periods of the ridges varied from 0.4 mm–1.7 mm and trough-to-peak heights from less rhan 10μm to about 60μm. Two Delphinapterus (monodontids) had ridges significantly larger than the Physeter and most delphinids, with spatial periods of 1.9–2.4 mm and heights 80–120 μm. We found the ridges distributed over much of the surface of the body, but relatively faint or absent on most of the head, the control surfaces, and the ventral region in some species. In all of the animals we observed, the ridges ran in an approximately circumferential direction around the body trunk rostral to the dorsal fin or mid-body area, but varied somewhat in direction in the caudal region and in other isolated areas. While the function of the cutaneous ridges has not been established, we speculate that they may play some role in tactile sensing, in the hydrodynamic characteristics of an animal, or both.     

CHEMOSURGERY IN CUTANEOUS MALIGNANCY

Chemosurgical removal of accessible cancer under microscopic control affords:1. Unprecedented reliability. “Silent” extensions may be followed out and eradicated.2. Conservatism in removal of tissue. With microscopic examination of each layer of tissue removed, it is possible to avoid removing more than one or two millimeters of healthy tissue beyond the extent of the cancer.3. Good cosmetic results in many instances.4. Relative freedom from operative pain.5. Possibly, lower incidence of metastasis.6. Low operative mortality.