Effect of CO2 enhancement in an outdoor algal production system usingTetraselmis

One of the objectives of microalgal culture is to provide reliable production technology for important live aquaculture feed organisms. Presented here are the results of experiments designed to provide a better understanding of the relationship between inorganic carbon availability and algal production.Our results suggest that through additions of CO₂ gas we were able to maintain sufficient dissolved carbon to stabilize outdoor algal cultures. Increases in the rate of addition of CO₂ increased levels of dissolved CO₂, total dissolved inorganic carbon (CO₂), and decreased pH in the growth medium. This translated into improved buffering capacity of the culture medium and higher growth rate. A minimum of 2.4 mM CO₂ was found necessary to maintain a maximal growth rate of 0.7 doublings/day. We also found that the increased productivity more than offsets the cost of adding the CO₂.     

Effect of temperature on yield and night biomass loss in Spirulina platensis grown outdoors in tubular photobioreactors

Outdoor experiments carried out in Florence, Italy (latitude 43.8° N, longitude 11.3° E), using tubular photobioreactors have shown that in summer the average net productivity of a Spirulina platensis culture grown at the optimal temperature of 35 °C was superior by 23% to that observed in a culture grown at 25 °C. The rates of night biomass loss were higher in the culture grown at 25 °C (average 7.6% of total dry weight) than in the one grown at 35 °C (average 5%). Night biomass loss depended on the temperature and light irradiance at which the cultures were grown, since these factors influenced the biomass composition. A net increase in carbohydrate synthesis occurred when the culture was grown at a low biomass concentration under high light irradiance or at the suboptimal temperature of 25 °C. Excess carbohydrate synthesized during the day was only partially utilized for night protein synthesis.     

厦门地区露地栽培多肉植物的种类筛选及其园林应用研究

本文介绍适合厦门地区露地栽培的仙人掌等多肉植物种类及其园林应用情况,并结合多年的观察记录,对这类植物的适应性进行评估和讨论,就其发展前景作简要阐述。     

Pilot culture of three strains of Dunaliella salina for β-carotene production in open ponds in the central region of Iran

Summary Three strains of Dunaliella salina (I, G and A) were cultivated under the climatic conditions of Iran, in open ponds to compare the β-carotene production and the specific rate of growth. The experiments were accomplished in two separate stages. In the first stage, the cells were grown in ponds on nutrient-rich medium containing 2 M NaCl to obtain the necessary biomass. In the second stage, cells were stressed on nutrient-poor medium containing 2.5 M NaCl for β-carotene induction. The results showed that the specific growth rate of strain I was the highest during the first stage, whereas during the second stage, the growth rates of three strains were approximately the same. The overall results indicated that strain G had the highest potential for β-carotene accumulation of the strains tested and hence it was concluded that this strain is more suitable for outdoor cultivation under the climatic conditions of Iran than the other two.     

动物学野外实习管理模式探讨

动物学野外实习是生命科学各专业教学计划的重要组成部分。在总结二十多年来野外实习经验的基础上,参考国内外一些做法,提出动物学野外实习的管理模式,包括实习的学时及安排,实习时间、地点的选择,实习组织形式及其职能,实习纪律和要求,实习中的安全防护,实习动员和总结六个方面。     

Effect of UV radiation on photoinhibition of marine macrophytes in culture systems

The present study examined the effect of UV andphotosynthetically active radiation (PAR) onphotoinhibition and recovery in the Phaeophyte Macrocystis pyrifera, the Rhodophyte Chondruscrispus and the Chlorophyte Ulva lactuca underoutdoor culture conditions. There was an increase inphotoinhibition as a consequence of high exposure toUV-B radiation in M. pyrifera, however, highlevels of PAR accounted for most of thephotoinhibition in C. crispus and U.lactuca. Photodamage by UV-A, UV-B and PAR wascompletely repaired within 5 h and effective quantumyield reached pretreatment values in the three speciesstudied. Species were less susceptible tophotoinhibition after being incubated for 5 d underhigh exposures of natural irradiance suggesting aphotoadaptive process. The recovery of the effectivequantum yield was impaired by long exposure to highlevels of UV-B in C. crispus and UV-A, UV-B andPAR in M. pyrifera. This suggests a differentkind of damage by UV-A and PAR radiation, one to thephotosynthetic apparatus and another which affects therepair mechanism of some species. There was anincrease in UV-absorption ( 330 nm) in M. pyrifera and C. crispus within four days ofthe initiation of the experiment suggesting that thesespecies photoprotect their photosynthetic system whenexposed to elevated UV and PAR levels.     

Environmental factors and allergic airway diseases

A number of epidemiological studies show that in the last few decades, all over Europe, there has been a growing increase in allergic respiratory disease, which affects between 15 to 30% of the population. There is compelling evidence that this rise in allergic illnesses depends mainly on the type of the environmental pollution and on the typical lifestyle of western countries. Community-based studies comparing people living in former East and West Germany have proved a high prevalence of allergic respiratory disease in West German cities, with variances due to the differences in indoor and outdoor pollution. Ozone, nitrogen oxides, and respirable particulate matter (PM10) are the main components of photochemical smog, typical of western countries. They can lead to sensitization and the onset of allergic illnesses with direct and indirect mechanisms. The casual relationship between automobile traffic-generated pollution, in particular diesel exhaust particles which act as adjuvant on pollen sensitization, and the increase in allergic sensitization to pollens was proved by epidemiological observations, which were later confirmed by studies of animal laboratory exposure. Indoor environment is probably as important in increasing the prevalence of allergic disease. Different housing habits, energy-efficient buildings, and modern air-handling systems have reduced ventilation and produced substantial changes in indoor environment and an increased exposure to allergens (housedust mites, mould and pets dander in particular). Like outdoor pollution, tobacco smoke, formaldehyde, volatile organic compounds, fire burning products, and other chemicals can enhance allergic sensitization with direct and indirect mechanisms. Increased exposure to allergens in the early years of life can influence the immune regulation and the evolution towards a prevailing Th2 response. Recent epidemiological observations lead us to conclude that in the onset of allergic airway illnesses environmental factors can play a greater role than genetic predisposition. This revised version was published online in June 2006 with corrections to the Cover Date.     

Exploring Ethograms in the Schoolyard: A Lesson on Animal Behavior

This article highlights a core lesson that has been used in a number of Lincoln Park Zoo educational programs. The lesson teaches students to conduct an ethological, or animal behavior, study on a bird. This study can be implemented in a variety of outdoor settings, including a park, schoolyard, or zoo. Using an ethogram, students will practice inquiry skills such as making observations, collecting and analyzing data, and sharing results. This type of inquiry-based research is commonly conducted at Lincoln Park Zoo and allows students to make a connection between their work and that of our practicing researchers. Furthermore, this lesson supports the recommendations of the National Research Council by providing students with an opportunity to engage in scientific inquiry and to utilize research skills in an outdoor setting.     

Animal Housing and Welfare: Effects of Housing Conditions on Body Weight and Cortisol in a Medium-Sized Rodent (Cavia aperea)

Rodents are the most abundant experimental nonhuman animals and are commonly studied under standard laboratory housing conditions. As housing conditions affect animals' physiology and behavior, this study investigated the effects of indoor and outdoor housing conditions on body weight and cortisol level of wild cavies, Cavia aperea. The changing housing condition strongly influenced both parameters, which are commonly used as indicators for animal welfare. The transfer from outdoor to indoor enclosures resulted in a body-weight loss of about 8%. In contrast, animals kept indoors showed a substantial weight gain of about 12% when they were transferred outdoors. These effects were reversible. To substantiate a connection between body-weight changes and the health states of the animals, blood basal cortisol concentrations were measured. Animals kept outdoors had significantly lower cortisol levels than did animals kept indoors. These results imply that indoor conditions have a direct effect on the animals' states. The physiological and metabolic consequences as well as potential welfare aspects should be taken into account when planning experimental work, especially on nondomestic animals.