Melanin pigmentation: an in vivo model for studies of melanosome kinetics within keratinocytes

The phagocytosis of latex beads by epidermal cells is proposed as a model for stludies on melanosome kinetics within the epidermis. Large latex beads (0.8 micrometer) are ingested singly, whereas, small beads (0.1 micrometer) are taken up in groups, results showing that the uptake mechanism depends on the size of thze indlividual particles. This size-dependency may explain the different distribution patterns of melanosomes and thus the differences of skin color in the Caucasoid and Negroid races.     

Decision theory: what "should" the nervous system do?

The purpose of our nervous system is to allow us to successfully interact with our environment. This normative idea is formalized by decision theory that defines which choices would be most beneficial. We live in an uncertain world, and each decision may have many possible outcomes; choosing the best decision is thus complicated. Bayesian decision theory formalizes these problems in the presence of uncertainty and often provides compact models that predict observed behavior. With its elegant formalization of the problems faced by the nervous system, it promises to become a major inspiration for studies in neuroscience.     

Abrupt tropical vegetation response to rapid climate changes

Identifying leads and lags between high- and low-latitude abrupt climate shifts is needed to understand where and how such events were triggered. Vascular plant biomarkers preserved in Cariaco basin sediments reveal rapid vegetation changes in northern South America during the last deglaciation, 15,000 to 10,000 years ago. Comparing the biomarker records to climate proxies from the same sediment core provides a precise measure of the relative timing of changes in different regions. Abrupt deglacial climate shifts in tropical and high-latitude North Atlantic regions were synchronous, whereas changes in tropical vegetation consistently lagged climate shifts by several decades.     

New real-time PCR tests for species-specific detection of Chlamydophila psittaci and Chlamydophila abortus from tissue samples

Chlamydophila psittaci and Chlamydophila abortus are the causative agents of avian chlamydiosis (psittacosis) and ovine enzootic abortion, respectively. Both pathogens are known to possess zoonotic potential. Due to their close genetic relatedness, direct and rapid species identification is difficult. In the present study, new real-time PCR assays are reported for both species. The tests are based on highly specific probes targeting the ompA gene region and were conducted as duplex PCRs including an internal amplification control. The Cp. psittaci assay successfully passed a proficiency test at national level. Examination of field samples revealed Cp. psittaci as the dominating species in birds, but also Cp. abortus in a few psittacines. Real-time PCR assays for species-specific detection of Cp. psittaci and Cp. abortus are suited for routine diagnosis, which renders them important tools for the recognition of outbreaks of psittacosis and ovine enzootic abortion.     

Impact of fish size,water temperature,and MS‐222 concentration on inducing general anesthesia in pikeperch (Sander lucioperca)

The aim of the study was to determine the optimum concentration of MS‐222 for given size groups of pikeperch and water temperatures. The study considered three size groups of pikeperch (body weight [BW] 8.56, 15.72, 52.91 g), an MS‐222 water solution (50, 100, and 150 mg/L), and two temperatures (20 or 23°C). It was revealed that the optimum MS‐222 concentration depended largely on the size of the pikeperch and on water temperature. For fish with a BW <10 g the recommended concentration is 100 mg/L but only at 23°C. For fish with a BW of 10–40 g at an immersion temperature of 20°C the safe MS‐222 concentration ranges from 100 to 150 mg/L. However, at a temperature of 23°C the recommended concentration of the anesthetic is 100 mg/L. Similarly for larger fish, that is, fish with a BW >40 g, the optimum MS‐222 concentration at a water temperature of 20°C is in the range of 100–150 mg/L, but at a temperature of 23°C is it approximately 100 mg/L. Additionally, when exposure to the anesthetic is shorter (several min), a concentration of 150 mg/L is also safe for juvenile pikeperch of this size.     

Effects of azadirachtin injection in litchi trees (Litchi chinensis Sonn.) on the litchi stink bug (Tessaratoma papillosa Drury) in northern Thailand

The litchi stink bug (Tessaratoma papillosa Drury) is one of the major pests of litchi (Litchi chinensis Sonn.) in tropical Asia. Systemic effects of azadirachtin (at a concentration of 0.17 g active ingredient per centimeter trunk diameter) on T. papillosa were examined by injecting the dissolved product (NeemAzal U) into the trunks of four caged litchi trees in an orchard in northern Thailand. Four untreated caged trees served as control. Mean weekly mortality rates of individuals released on the treatment date (initially 55 nymphs per cage) were significantly higher in the treatment cages (55%) than in the control cages (10%) between the second and the fourth week of the experiment. Mortality in the treatment cages was probably due to both toxic effects (ecdysis inhibition) and antifeedant effects (starvation). Weekly mortality rates of individuals released 2 weeks after tree injection (initially 20 nymphs per cage) were not significantly different between treatment and control cages, indicating a weakening effect of azadirachtin, 2–3 weeks after tree injection. Azadirachtin concentration in ripe fruits was less than 5 mg/kg fruit pulp 18 days after tree injection. Although the results of this study are not yet sufficient for practical recommendations, they provide indications of alternative options for integrated pest management approaches. The azadirachtin tree injection method should also be tested against other pests of litchi, and of fruit trees in general.     

Reclamation of land damaged by open-cast mining—Methods and results

Land damaged by strip-mining can be restored to multiple and profitable use under the guidance and control of administrative bodies (district governments) on the basis of long-term planning and continuous consultations between mining firms and subsequent users. Through appropriate economic planning and collaboration, land used for open-cast or strip lignite mining can be returned to productive agriculture and forestry, thus realizing the fundamental potential uses of the area for this primary means of production. Land reclamation in the German Democratic Republic provides an example of optimum utilization of formerly derelict mining areas.