FACTORS AFFECTING THE AGE OF FIRST BREEDING OF THE KITTIWAKE RISSA TRIDACTYLA

At a Kittiwake colony in Northumberland, 80% of those birds which returned to their natal colony to breed were males and these supplied 52% of all male recruits. More females breed away from their natal colony than males. There was no differences in the proportions of young fledged from sites in the centre or at the edge of the colony, or by parents of different experience, which returned to breed. Kittiwakes breed for the first time at ages from 3 to 8 years, but most at 4 or S years old. Males arrive back at the colony at an earlier age than females and breed for the first time one year earlier. Males obtaining sites at the centre of the colony first breed at an earlier age than those at the edges. Neither the age nor the area of first breeding appear to be transmitted from parent to offspring. Males breeding first aged 4 years or younger produced more young than those which first bred aged 5 years or older, despite their partners laying smaller clutches. This difference was most marked among those males recruited to sites in the centre of the colony. The advantage of this earlier breeding is counteracted by a lower survival rate among those males which start to breed at the younger ages. In all breeding Kittiwakes, annual reproductive output increases with experience while annual survival rates decrease. Once they had started to breed, many birds failed to breed in one subsequent season. Nearly 60% of these cases of intermittent breeding occurred in the year following first breeding. Intermittent breeding was most frequent among young birds and among females. It is suggested that each breeding involves a cost to the individual in terms of reduced survival, and that deferred and intermittent breeding are means of guarding survival. A model is proposed whereby the age at which a bird starts to breed, the nesting site which it obtains, and its subsequent breeding strategy result in each individual producing an optimal number of reproducing offspring in its lifetime, relative to its quality.     

影响库蚊幼虫摄食鱼腥藻的因素

在实验室条件下,致乏库蚊幼虫可大量摄食鱼腥藻,并能消化利用,完成生活史。鱼腥藻在蚊幼虫肠道中滞留时间约6h,酵母约5h,鱼腥藻比酵母稍难消化。对比幼虫孵化至化蛹周期,饲喂鱼腥藻为194h,而饲喂酵母则为142h,饲喂鱼腥藻比饲喂酵母延缓了蚊幼虫期52h。致乏库蚊幼虫摄食鱼腥藻的适宜条件为:pH7-8,温度25-30℃,藻液浓度愈高,摄食越多。随着蚊幼虫的生长,摄食量递增。     

建兰根状茎增殖条件的研究

研究了建兰两个栽培品种的根状茎在固体及液体两种培养方式,以及培养基中有无激素和不同激素浓度配比对增殖及分化的影响。根状茎在液体培养基上的生长量都大于固体培养基上的生长量。根状茎在无激素的培养基上也能增殖。加入激素有促进作用。合适的激素浓度及配比因品种而异。     

影响干扰素治疗慢性乙型肝炎疗效因素分析

为了解重组干扰素α２ｂ治疗慢性乙型肝炎疗效的影响因素,对住院治疗的１０８例慢性乙型肝炎进行研究。治疗前所有病例ＨＢｓＡｇ、ＨＢｅＡｇ、ＨＢＶＤＮＡ均阳性,ＡＬＴ均大于正常值３倍。结果发现,总有效率女性高于男性（Ｐ＜００５）;病程短于３年者明显优于长于３年者（Ｐ＜００１）;ＣＡＨ明显高于ＣＰＨ（Ｐ＜００１）。９例治疗无效者,２例检出前Ｃ区变异;１例野生株和变异株混合感染者疗程结束后表现为无效。４７例治疗无效者（包括部分复发者）,检出干扰素中和抗体２例;结合抗体６例。治疗期间有类流感症状者显效率明显高于无反应者（Ｐ＜００１）;总有效率高于无反应者（Ｐ＜００５）。治疗中ＡＬＴ升高大于基值２倍以上者疗效更好（Ｐ＜００１）。结果表明,干扰素治疗慢性乙型肝炎疗效的影响因素较多。     

FACTORS AFFECTING THE REDISTRIBUTION OF SURFACE-BOUND CONCANAVALIN A ON HUMAN POLYMORPHONUCLEAR LEUKOCYTES

Human neutrophil polymorphonuclear leukocytes (PMN) were studied to determine the influence of cellular locomotion upon the redistribution and capping of concanavalin A (Con A). Con A was detected by fluorescence (using Con A conjugated to fluorescein isothiocyanate [Con A-FITC]), or on shadow-cast replicas (using Busycon canaliculatum hemocyanin as a marker for Con A). After labeling with Con A 100 µg/ml at 4°C and warming to 37°C, locomotion occurred, and the Con A quickly aggregated into a cap at the trailing end of the cell. When locomotion was inhibited (with cytochalasin B, or by incubation in serum-free medium at 18°C) Con A rapidly formed a cap over the central region of the cell. Iodoacetamide inhibited capping. PMN labeled with FITC, a monovalent ligand, developed caps at the tail only on motile cells; FITC remained dispersed on immobilized cells. PMN exposed to Con A 100 µg/ml at 37°C bound more lectin than at 4°C, became immobilized, and showed slow central capping. The Con A soon became internalized to form a perinuclear ring. Such treatment in the presence of cytochalasin B resulted in the quick formation of persistent central caps. Colchicine (or prior cooling) protected PMN from the immobilizing effect of Con A, and tail caps were found on 30–40% of cells. Immobilization of colchicine-treated cells caused Con A to remain in dispersed clusters. Thus, capping on PMN is a temperature- and energy-dependent process that proceeds independently of cellular locomotion, provided a colchicine-sensitive system is intact and the ligand is capable of cross linking receptors. On the other hand, if the cell does move, it appears that ligands may be swept into a cap at the tail whether cross-linking occurs or not.     

FACTORS AFFECTING THE INTRACELLUALR SYNTHESIS OF KYNURENINE

Near the time of pupation, autofluorescent kynurenine globules appear in the cells in the anterior region of the fatbody of Drosophila melanogaster. It has been reported previously that kynurenine synthesis may be induced in an additional group of fat cells by feeding the precursor tryptophan to Drosophila larvae, and that this induction of kynurenine production viewed within the fat cells is correlated with an increase in tryptophan pyrrolase activity. In the present report, conditions are outlined which result in the appearance of kynurenine in all of the fat cells. The number of cells in the fatbody which contain kynurenine is influenced by the quantity of tryptophan included in the diet, as well as by the developmental stage at the time of treatment and the duration of the feeding period on the inducer. Physical barriers modifying permeability, such as the membranous layer noted surrounding the fatbody, may be a factor in the regulation of the time and nature of the cellular induction of kynurenine synthesis. Another factor to be considered is the possibility of interference with the availability of tryptophan as a substrate or inducer for this synthesis within the cell. It is suggested that the occurrence of pteridines in some of the fat cells may modify the response of these cells to produce kynurenine, since pteridines as electron acceptors can complex with tryptophan as an electron donor. Kynurenine may be produced in the fat cells under in vitro conditions when they are incubated with L-tryptophan, but kynurenine is not formed when fat cells are incubated with D-tryptophan. The in vitro studies further demonstrate that induction of kynurenine synthesis may occur in fat cells isolated from young larvae in contrast, to in vivo conditions in which inducer does not effect an earlier appearance of kynurenine in the larval fatbody.     

影响四季桔器官发生的因素

对四季桔胚轴直接出芽、愈伤组织诱导及植株再生能力的研究表明：上、下胚轴在含有BA的MT培养基上,均能直接出芽,但上胚轴出芽能力明显高于下胚轴,最高出芽率为96．9％。外植体在培养基上的接种方式,对出芽也有一定影响,上胚轴切段以形态学下端垂直插入,出芽率高,且在培养前期表现尤为突出。胚轴愈伤诱导的适宜培养基为MT＋IBA0．5mg-1＋BAgmg-1。愈伤组织分化时,上、下胚轴愈伤组织所要求的BA浓度分别为4mgL-1及2mgL-1。在根的诱导中,附加的生长素种类,不仅影响生根率的高低,而且影响上部茎叶的生长,其中以加入lmgL-1IBA的效果最好,生根率达84．4％。     

FACTORS AFFECTING THE FOOD SUPPLY AND BREEDING SEASON OF RESIDENT BIRDS AND MOVEMENTS OF PALAEARCTIC MIGRANTS IN A TROPICAL AFRICAN SAVANNAH

The fact that Palaearctic migrants arrive in the northern tropical savannah of Africa during the dry season suggests potential competition for food with African species. Moreover, in the southern tropical savannah African species breed during the rainy seasons, when Palaearctic migrants are present. In the equatorial area of Serengeti, East Africa, an index of the food supply for insectivorous birds was obtained from 3 years of light-trap measurements and sweep net samples. Adults of Lepidoptera, Coleoptera, Orthoptera and Isoptera are sparse in the dry season but become locally abundant after the first rainstorms that mark its close. They are apparently blown by converging winds ahead of the inter-tropical front and settle to lay eggs where rain has fallen. These early storms therefore produce localized superabundances of food. In the ensuing rainy seasons insect abundance remains high. African insectivorous birds breed during the wet period, reaching a peak two months after the insect increase. It is suggested that this lag is due to the need to recover body condition, build up reserves for eggs, develop gonads and wait for vegetation and insect larvae to develop. In the samples available, breeding records of above-ground nesters peaked in the first rains, while ground-nesters peaked in the second (main) rains. Predators bred towards the end of the rains, when there is an abundance of fledglings and small mammals. Thus the food supply could act as the ultimate factor determining the timing of the breeding season in this area. Palaearctic migrants arrive in the Serengeti 4–10 weeks ahead of the main rain front. However, most species are only found where rain has fallen recently. When conditions dry up they move on to other wet areas. Thus they overlap with African species only where there is a superabundance of insects. When the rains become widespread Palaearctic migrants disperse into their usual habitats, and therefore appear not to compete for available resources with closely related species of African birds. The situation in West Africa, where residents and migrants overlap throughout the dry season, cannot be explained in the same terms.     

影响舟山群岛蛙类物种多样性的主要因素分析

分析了面积、海拔高度、离物种源的最小距离、岛屿形状和人类活动对舟山群岛蛙类物种多样性的影响。结果显示,物种多样性与岛屿面积和最高海拔明显相关。但物种多样性与离物种源的最小距离没有显著相关性,这说明岛屿形成后蛙类在岛屿间（或岛屿和大陆间）很少发生迁移和再定居,物种数处于“非平衡”状态。岛屿形状不影响物种多样性。人类活动对物种多样性影响较小,原因是舟山群岛没有专一性的林栖种类,除淡肩角蟾外,其余种类均能生活于农田栖息地。我们认为,岛屿面积是舟山群岛蛙类物种多样性的主要决定因素和最佳预测者。     

影响肝癌周围肥大细胞数量的相关因素研究

探讨影响肝癌周围肥大细胞数量的相关因素及其意义。采用二乙基亚硝胺诱发大鼠肝癌模型。应用光镜,免疫组织化学,核酸原位分子杂交和细胞图像分析技术,检测肝癌细胞转化生长因子β（TGFβ）,血管内皮生长因子（VEGF）,c-fosmRNA的表达与癌周肥大细胞（MS）数量变化的相关性。结果显示肝癌细胞浆中TGFβ,VEGF和c-fosmRNA呈阳性表达,其中TGFβ,c-fosmRNA表达的强度与癌周MC数量变化呈平行关系。而VEGF表达的强度与癌周MC数量变化无关。结果表明：肝癌细胞通过释放TGFβ并通过激活原癌基因（c-fos)以旁分泌方式或癌基因产物影响癌周MC的数量。     

SOME SOIL FACTORS AFFECTING VERTICILLIUM WILT OF ANTIRRHINUM

Variations in the application rates of chalk and superphosphate and the omission of all the fertilisers had no visible effect on the incidence of wilt caused by any of the five Verticillium species.
he literature dealing with the influence of soil conditions upon the Verticillium wilt of a wide range of host plants is reviewed. It is shown that the species V. alboatrum, V. dahliae, V. nigrescens, V. nubilum and V. tricorpus vary inter se in their pathogenicity to Antirrhinum majus, and that their infectivity may be influenced by soil treatments. Thus, in pot cultures, the incidence of antirrhinum wilt induced by Verticillium dahliae and V. nigrescens was reduced by increasing sulphate of potash or ammonium sulphate; or by decreasing soil moisture. Very wet soil and heavy dressings of hoof-and-horn were the only conditions under which V. nubilunt and V. tricorpus induced wilt symptoms. Z7. albo-atrunt was the most virulent species tested; none of the soil treatments decreased its pathogenicity.