Differential effect of vasoactive intestinal peptide, somatostatin, and substance P on human IgE and IgG subclass production.

We studied the effect of vasoactive intestinal peptide (VIP), somatostatin (SOM), and substance P (SP) on IL-4-stimulated human IgE and IgG subclass production. VIP and SOM, but not SP, inhibited IgE production without affecting IgM or IgA production by mononuclear cells (MNC) from nonatopic donors from 10 pM to 10 nM. These neuropeptides also differentially modulated IgG subclass production. While IgG1 production was not affected by VIP, SOM, or SP, all of the neuropeptides enhanced IgG2 production. By contrast, SOM and SP, but not VIP, inhibited IgG3 production, whereas VIP and SP, but not SOM, enhanced IgG4 production. The effect by neuropeptides was specific since each peptide effect was specifically blocked by each antagonist. To achieve this effect, neuropeptides must be added at the start of the culture and be present throughout the entire culture period. The inhibition of IgE production was not mediated by known inhibitors of IgE production, IFN-gamma or PGE2, because the addition of anti-IFN-gamma mAb (10 micrograms/ml) or indomethacin (0.1 microM) did not overcome the inhibition of IgE production. In contrast to MNC, neuropeptides did not affect IgG subclass production in purified B cells. IgE production was not induced by IL-4 in purified B cells. Neuropeptides also failed to modulate IgG subclass production in cultures of B cells with either T cells or monocytes. However, they modulated IgE production and IgG subclass production in B cells in the presence of T cells and monocytes. In purified B cells, IL-4 plus anti-CD40 mAb induced IgE production which was not inhibited by VIP or SOM. However, VIP or SOM, but not SP, inhibited IgE production in B cells cultured with both T cells and monocytes. Finally, the mechanism of modulation of IgE and IgG4 production was dependent on IL-4-induced switching, since neuropeptides modulated IgG4 and IgE production in surface IgG4-negative (sIgG4-) and sIgE- B cells, respectively. In contrast, modulation of IgG2 and IgG3 production was not due to switching, since neuropeptides did not affect either IgG2 or IgG3 production in sIgG2- or sIgG3- B cells, respectively.     

Inhibition of aldosterone production by alpha-human atrial natriuretic polypeptide is associated with an increase in cGMP production

Synthetic alpha-human atrial natriuretic polypeptide caused rapid and marked inhibition of aldosterone production in dispersed rat adrenal capsular cells. The polypeptide also slightly, but significantly, decreased cAMP production in the adrenal dispersed capsular cells, while markedly stimulating cGMP production. The cGMP production was accelerated at the concentration of alpha-human atrial natriuretic polypeptide lower than the threshold level to stimulate aldosterone production. These findings suggest that alpha-human atrial natriuretic polypeptide possibly plays a regulatory role in aldosterone production and an additional role in natriuresis through inhibition of aldosterone production. The stimulation of cGMP production by alpha-human atrial natriuretic polypeptide may be involved in the inhibitory effect of this peptide on aldosterone production.     

Effect of sub-inhibitory concentrations of antibiotics on the virulence of Staphylococcus aureus

The production of virulence factors by various bacteria can be influenced by sub-inhibitory concentrations of antibiotics. The effect of six antibiotics on the production of representative extracellular enzymes and toxins produced by Staphylococcus aureus was investigated. The production of the virulence determinants coagulase, protein A, alpha and delta haemolysin was monitored in the presence of ciprofloxacin, enoxacin, chloramphenicol, gentamicin, tetracycline and methicillin. The protein synthesis inhibitors reduced the production of coagulase and protein A, and almost completely inhibited the production of the haemolysins. Haemolysin production was also reduced by ciprofloxacin and enoxacin, but these antibiotics had little effect on the production of coagulase and protein A. Methicillin stimulated the production of alpha and delta haemolysins but had no effect on the production of coagulase and protein A.     

The role of Chironomidae in energy flow of a lotic ecosystem

Chironomid secondary production was estimated on a species-specific basis for 14 dominant taxa in a third-order woodland stream. Results from this study were used to provide an expalanation for the common observation that benthos secondary production in streams is insufficient to account for levels of fish production,i.e., the ALLEN paradox. Annual chironomid secondary production was 29.7 g dry mass m^–2 and accounted for 80% of the total aquatic insect secondary production. A contribution by chironomids this high has not been reported previously from similar streams and indicates that chironomids are an energetically important group available for fish consumption. Most studies examining chironomid secondary production group all taxa at the family level and calculate secondary production for the entire family using the size-frequency method. This approach violates assumptions of the size-frequency method and will result in inaccurate and unpredictable estimates of chironomid secondary production. The species-specific approach to estimate chironomid production used in this study, combined with non-chironomid production, yielded a benthos annual production rate that exceeded consumption necessary to support fish production.     

Clay turbidity and the relative production of bacterioplankton and phytoplankton

A comparison of phytoplankton with bacterioplanktonproduction as each ismodified by high concentrations of suspended clays ispresented. High clayturbidity caused light-limition of water columnphytoplankton production.However, the clay combined with DOC to form aggregateswhich supportedbacterioplankton production. Consequently,bacterioplankton production wasrelatively high at 42% of total small particleproduction in this lake.Bacterioplankton abundance and biomass was stronglycorrelated withphytoplankton chlorophyll a for most of the lake. Because of the association ofbacterioplankton with the clay-organic aggregates, DOCwas not a good predictorof bacterioplankton abundance or production. POC(primarily OC associatedwith clay) was correlated with bacterioplanktonabundance over most of thelake. Bacteria production was substrate limited asshown by much greaterbiomass-specific production at smaller bacteriapopulation sizes. Multipleregression analysis showed that specificbacterioplankton production wasprimarily governed by POC and secondarily by rates ofphytoplanktonproduction. Thus clay, because of light limitedphytoplankton production,negatively impacts bacterioplankton production yet atthe same time facilitatiesbacterial production by concentrating OC with theformation of the clay-organicaggregate.     

The Organization of Craft Production at Vijayanagara, South India

This article examines the production of two classes of goods, textiles and ceramics, in the medieval South Indian empire of Vijayanagara. A general model for the organization of specialized craft production is presented in which productive organization is linked to political/administrative regulation of product manufacture, distribution, and use. Three modes of productive organization are defined: administered production, centralized production, and noncentralized production. Historic documentation is used to examine Vijayanagara textile production, and a centralized productive organization is proposed. Vijayanagara ceramic manufacture is assessed through archeological and ethnographic data, and a noncentralized production system is proposed.     

Stimulation of Cyclic GMP Production via a Nitrosyl Factor in Sensory Neuronal Cultures by Algesic or Inflammatory Agents

Abstract: Capsaicin stimulates cyclic GMP production via nitric oxide (NO) (or another nitrosyl factor) in dorsal root ganglion (DRG) neurons maintained in culture. The purpose of the present study was to characterize further capsaicin stimulation of cyclic GMP production in DRG cells maintained in culture, investigate other algesic and/or inflammatory agents for effects on cyclic GMP production, and examine cells responsible for NO production and cyclic GMP production. Capsaicin stimulation of cyclic GMP production in DRG cells was dose dependent, receptor mediated, and attenuated by hemoglobin. Prostaglandin E₂, substance P, and calcitonin gene-related peptide did not affect basal, capsaicin-stimulated, or bradykinin-stimulated cyclic GMP production. Other inflammatory or algesic agents, including serotonin, histamine, ATP, glutamate, aspartate, and NMDA, did not affect cyclic GMP production. Pretreatment of DRG cells with lipopolysaccharide increased basal cyclic GMP production in neuronal but not in nonneuronal cultures and facilitated stimulation of cyclic GMP production by l -arginine. Capsaicin pretreatment of neuronal DRG cultures, which destroys capsaicin-sensitive (small diameter) afferent neurons, attenuated capsaicin- and bradykinin-stimulated cyclic GMP production but did not affect basal or sodium nitroprusside-stimulated cyclic GMP production. These results indicate that capsaicin elicits production of a nitrosyl factor via capsaicin-sensitive (small diameter) neurons. Capsaicin evoked cyclic GMP production in nonneuronal DRG cultures in the presence but not in the absence of apposed neuronal DRG cultures. Overall, these findings suggest that specific exogenous (or endogenous) substances may stimulate production of a nitrosyl factor(s) by a subset of DRG neurons, and nitrosyl factors produced by these neurons may affect cyclic GMP production in neighboring neuronal or non-neuronal cells.     

Heat production during sleep

Heat production during sleep was studied by continuous indirect calorimetry with simultaneous electroencephalographic monitoring. Controlling for gross influences on heat production, comparisons of heat production during different sleep stages showed heat production in stage 4 sleep to be significantly lower than in other sleep stages. There appeared to be a gradation in heat production in non-rapid-eye-movement stages of sleep with stage 2 higher and stage 4 lower than stage 3. Heat production in stage 4 was less variable than in any other sleep stage. Both the level and variability of heat production was similar in stage 2 and rapid-eye-movement sleep. Heat production during the night was 9% lower than during resting wakefulness. The average heat production in stage 4 sleep was 14.4% lower than resting wakeful values.     

Bioreactor and process design for biohydrogen production

Biohydrogen is regarded as an attractive future clean energy carrier due to its high energy content and environmental-friendly conversion. It has the potential for renewable biofuel to replace current hydrogen production which rely heavily on fossil fuels. While biohydrogen production is still in the early stage of development, there have been a variety of laboratory- and pilot-scale systems developed with promising potential. This work presents a review of advances in bioreactor and bioprocess design for biohydrogen production. The state-of-the art of biohydrogen production is discussed emphasizing on production pathways, factors affecting biohydrogen production, as well as bioreactor configuration and operation. Challenges and prospects of biohydrogen production are also outlined.     

黄土高原-青藏高原过渡带农户生产系统的能值分析——以通渭-渭源-夏河样带为例

通渭-渭源-夏河样带位于黄土高原向青藏高原过渡的生态区,是我国典型农牧交错带。长期以来,不合理的农业生产结构带来生态、经济等一系列问题,制约了该地区草地农业的持续发展。为此,从能值角度分析区域农业生产结构,可为农(牧)户决策提供理论依据,为优化区域农业生产结构提供科学依据。收集研究区农户作物和家畜生产的投入-产出数据,用能值方法分析农户生产系统结构特征、农户生产决策行为及生产系统耦合作用,用结构方程模型(SEM)分析农户生产系统能量的组分间流动。研究发现,随海拔增高,农户作物生产活动减少,作物总产出能值递减;尽管作物生产主要投入和产出要素相同,但同一作物不同地点的同一要素投入、产出能值和能值收益率均存在显著差异(P0.05);同一地点不同作物的同一要素投入、产出能值和能值收益率均差异显著(P0.05);作物生产投入要素中,有机肥能值在通渭和渭源均有较高贡献;作物投入和产出能值的农户生产决策阈值自东向西递减,在能值投入初始增加时,夏河农户作物生产规模扩增最为迅速。家畜养殖规模、能值投入和产出自东向西递增;通渭和渭源,小麦秸秆和苜蓿作为中间投入,能值贡献率达到80%;夏河家畜生产投入要素中,补饲粮食能值贡献率高达90%;家畜投入和产出能值的农户生产决策阈值点自东向西递增;能值收益率随耦合度的增加呈指数上升,通渭和渭源能值收益率的增加速度,随耦合度的增加趋于缓慢,而夏河能值收益率增速随耦合度的增加而上升。调整作物生产内部粮、经、饲产品比例结构,加强作物生产与家畜生产耦合作用,优化天然草地利用方式,实现生态效益最大化;阈值点调控农户生产决策行为,实现该区域农业生产结构优化。     

氨水流加用于粪产碱杆菌热凝胶发酵

热凝胶是粪产碱杆菌(Alcaligenes faecalis)在氮源限制条件下生成的水不溶性胞外多糖,分泌到胞外后就附着在菌体外壁,因此在细胞生长期提高生物量对促进热凝胶合成有重要意义。热凝胶分批发酵时, 起始NH4Cl浓度提高到3.6 g/L时能促进菌体生长和热凝胶合成,但是过量NH4Cl会抑制热凝胶合成,且生物量提高不是很明显。为了进一步提高菌体浓度, 在菌体生长期, 氨水取代NaOH溶液进行流加控制pH为7.0, 随后又用2 mol/L NaOH控制pH 5.6。实验表明, 氨水流加使菌体浓度大大提高,流加24 h使菌体浓度达到18.8 g/L。但是菌体浓度过高也会抑制热凝胶的合成,在氨水流加14 h时,菌体浓度在11.9 g/L左右, 热凝胶产量最高（72 g/L）。     

Cholesterol selectively enhances in vitro latex-specific IgE production in atopic dermatitis patients with latex allergy

Effect of cholesterol on in vitro latex-specific IgE production by mononuclear cells from atopic dermatitis patients with latex allergy. Cholesterol enhanced latex-specific IgE production in a dose-dependent fashion, and maximal enhancement was achieved at 1 microg/ml. In contrast, cholesterol had no effect on latex -specific IgA or IgG4 production. Study for cytokine production revealed that cholesterol decreased latex-induced production of IFN-gamma and IL-12, while it increased latex-induced production of IL-4, IL-10 and IL-13. These results indicate that cholesterol skews cytokine pattern toward Th2 type. Collectively, cholesterol may increase allergen-specific IgE production, which may in turn aggravate allergic symptoms.     

Interactive effects of herbivory and sand burial on growth of a tropical dune plant, Ipomoea pes-caprae

1. This study examined the effects of insect herbivory, sand burial, and the interactive effects of these factors, on the growth of beach morning glory, Ipomoea pes-caprae, a common tropical dune plant. Levels of herbivory and sand burial were manipulated on individual shoots, and effects on stem growth, leaf production, and production of adventitious roots and axillary branches by nodes were examined.
2. Sand burial had a significant positive effect on the production of roots, but did not affect growth in stem length or leaf production.
3. Effects of herbivory were consistently negative, and persisted for 6 weeks after the herbivore damage was incurred. Stem growth rates and leaf production decreased and the production of bare nodes (with no roots or branches) and mortality of apical meristems increased.
4. Interactive effects of herbivory and sand burial influenced both leaf production and root production. In the case of root production, the effects of herbivory in decreasing the proportion of nodes that produced roots occurred only in the presence of burial. In contrast, burial masked the negative effects of herbivory on leaf production.     

氨水流加用于粪产碱杆菌热凝胶发酵

热凝胶是粪产碱杆菌(Alcaligenes faecalis)在氮源限制条件下生成的水不溶性胞外多糖,分泌到胞外后就附着在菌体外壁,因此在细胞生长期提高生物量对促进热凝胶合成有重要意义。热凝胶分批发酵时, 起始NH4Cl浓度提高到3.6 g/L时能促进菌体生长和热凝胶合成,但是过量NH4Cl会抑制热凝胶合成,且生物量提高不是很明显。为了进一步提高菌体浓度, 在菌体生长期, 氨水取代NaOH溶液进行流加控制pH为7.0, 随后又用2 mol/L NaOH控制pH 5.6。实验表明, 氨水流加使菌体浓度大大提高,流加24 h使菌体浓度达到18.8 g/L。但是菌体浓度过高也会抑制热凝胶的合成,在氨水流加14 h时,菌体浓度在11.9 g/L左右, 热凝胶产量最高（72 g/L）。     

Bacterial secondary production and it relation with primary production in the Embalse del Río III Reservoir,Argentina

During an annual period the bacterial biomass (epifluorescence) and secondary production (methyl-³H-thymidine incorporation), as well as biomass (Chlorophyll) and algal primary production (incorporation of NaH¹⁴CO₃) were studied in the Embalse del Río III Reservoir, Argentina. The relations between these variables and their responses to seasonal changes in water temperature were analyzed. A close relationship in seasonal patterns of algal primary production and bacterial secondary production was observed, with the estimated rates of bacterial production similar to that obtained by other authors in eutrophic lakes. Bacterial production was 17 to 46% of the primary production, thus, at 60% assimilation efficiency, the bacterioplankton would consume 28 to 77 % of the total fixed carbon. Seasonal trends in algal primary production and bacterial secondary production were mainly affected by temperature.     

红壤丘陵区粮食生产的生态成本

人类的生产活动必然对资源与环境造成影响,以红壤丘陵区的湖南省祁阳县为研究对象,应用经济学和生态学方法,对粮食生产中的生态成本进行了研究。结果表明:2008年该区粮食生产生态损失总价值相当于当年农业总产值的4.85%;早、中、晚稻生态成本已分别达到3.18、2.44、3.02元/kg,而出售单价分别为1.76、1.90、1.84元/kg,高成本低收益的情况对该区域的可持续发展产生着不利影响;在当前生产力水平条件下,适度提高化肥、农药、农业机械、农膜、劳动力的投入,提高水稻产量,扩大家庭种植规模,可降低生产单位水稻的生态成本。     

Network regulation of the immune response: modulation of suppressor lymphocytes by alternative signals including contrasuppression

In the preceding paper we demonstrated that comparison of alternative designs for the immune network can be used to examine the functional significance of specified interactions in normal immune responses. In this paper we examine mathematically the functional significance of three interactions affecting the production of suppressor lymphocytes involved in regulation of normal immune responses. The interactions examined in detail are 1) antigenic stimulation of the production of suppressor lymphocytes, 2) idiotypic stimulation of the production of suppressor lymphocytes, and 3) antigenic inhibition of the production of suppressor lymphocytes (i.e., contrasuppression). The results of our analysis suggest that an immune system with only antigenic stimulation of suppressor production is less effective than a system with both antigenic and idiotypic stimulation of suppressor production on the basis of all of the criteria examined in this study. In turn, the latter system is less effective than a system with only idiotypic stimulation of suppressor production. Furthermore, a system with both idiotypic stimulation and antigenic inhibition of suppressor production can be equal or superior to a system with only idiotypic stimulation of suppressor production on the basis of the same criteria. Similar conclusions hold for the comparison of systems in which regulation by the suppressor lymphocytes of interest is exerted upon production of effector molecules rather than upon production of effector lymphocytes, and also for the comparison of systems in which interactions affecting the production of suppressor factors are of interest.     

脂氧合酶在诱导红豆杉细胞产紫杉醇中的作用

对红豆杉悬浮培养细胞中脂氧合酶(LOX)在诱导子诱导紫杉醇合成中的作用进行了探讨。结果表明真菌诱导子处理可提高细胞内LOX的活性和紫杉醇的产量,而诱导前用LOX抑制剂菲尼酮处理,可完全抑制诱导子对LOX活性和紫杉醇合成的诱导作用。说明LOX途径可能参与了紫杉醇的合成过程。外加茉莉酸甲酯也可激活LOX活性和紫杉醇合成,诱导前用菲尼酮处理可抑制诱导子诱导的LOX活性和紫杉醇合成,说明外源茉莉酸甲酯可能是通过激活细胞内LOX途径而启动下游紫杉醇的合成。为了进一步研究脂氧合酶在紫杉醇合成中的作用。我们还对红豆杉细胞脂氧合酶的分布和分子量等性质进行了研究。     

Spatial distribution of nectar production in a natural Echium vulgare population: Implications for pollinator behaviour

The distribution of trait values in many populations is not homogenous but creates a mosaic of patches. This may lead to differences in selection on the patch level compared to selection on the population level. As an example we investigated the spatial distribution of nectar production and its effects on pollinator behaviour in a natural population of Echium vulgare. Nectar production per flower, number of flowers and total nectar production showed a hierarchy and spatial aggregation as expressed by Gini coefficients and significant Moran's I values. Plants in patches of high nectar production received significantly more pollinator visits and had a significant emanating effect on pollinator visits of neighbouring plants. The same was true for plants in patches with high number of flowers. To disentangle these effects a path analysis was applied, which suggested that the direct effect of nectar production per flower although present, seems to be small compared to the effect of the number of flowers. Nectar production per flower affected pollinator visits mainly indirectly by way of total nectar production, which includes the effect of number of flowers. Assuming a minor pollinator-mediated selection for number of flowers, pollinator-mediated selection for total nectar production equals that for nectar production per flower. If so, the observed spatial structure of nectar production and its emanating effect on pollinator behaviour is of importance for natural selection. Plants of low nectar production occurring close to patches of plants with high nectar production benefited from the enhanced pollinator service of their neighbours while saving costs of increased nectar production. Consequently, plants with low nectar production may have a selective advantage at patch level while plants with high nectar production may have a selective advantage at population level. Results presented stress the importance of small-scale patterns for ecological relationships and evolutionary change.     

微藻光合作用制氢——能源危机的最终出路?

微藻光合作用制氢是解决能源短缺问题的有效途径.本文介绍了微藻光合作用制氢的机理,包括蓝藻固氮酶和可逆氢酶产氢以及绿藻可逆氢酶产氢的机理.在分析光合制氢限制因素的基础上,指出筛选和构建高效放氢藻株是制氢的有效途径.然后介绍了“直接生物光解”、固氮酶放氢和“间接生物光解”等制氢方式.利用绿藻“间接生物光解”水制氢是一种最有发展潜力的制氢方式.本文最后展望了微藻光合制氢的前景.