Browsing by Subject "Duftstoff"

Now showing 1 - 3 of 3

Determination of potentially hazardous oxidation products in cosmetics containing lanolin or 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone (OTNE)
(2019) Schrack-Belschner, Sonja Miriam Irmgard; Schwack, Wolfgang
Cosmetic products are important consumer goods in the "non-food" sector, which should not have negative effects of the human health. Critical compounds, however, can be formed by the oxidation of an unsaturated organic compound.Thereby formed oxidation products with potentially adverse properties are well known from the food sector. As the oxidation of cosmetic ingredients, however, has less been studied, the oxidation of selected cosmetic ingredients with respect to the formation of potentially critical compounds was investigated within the framework of this thesis.The oxidation of cholesterol to various cholesterol oxidation products (COPs) was investigated in a first step.COPs are known from the food sector and are suspected of causing certain diseases such as arteriosclerosis.Cosmetic products have not yet been tested for COPs, although a versatile ingredient used only in cosmetic products, lanolin, contains above-average levels of the cholesterol, which is the precursor.Total COPs contents in cosmetics containing lanolin, namely lip care products, fat creams and ointments for nursing women were in the low percent range (up to 3 %) and were thus several orders of magnitudes higher than the contents found in food.The oxidation of fragrances was studied in the second part of this work.The subject is not new as the oxidation of terpenes to contact allergens has been studied in earlier studies. The oxidation of other fragrances was hardly investigated. In order to extend our knowledge in this field, the oxidation of a synthetic fragrance frequently used in perfumes, octahydro tetramethyl naphthalenyl ethanone (OTNE) was studied. Obtained results indicated that peroxides of OTNE were formed during oxidation.It was found out that the OTNE oxidation even occurs, when perfumes are stored indoors under normal temperature and light conditions. An in-vivo test showed that OTNE oxidation can be expected on the skin after application of a perfume.
Molecular elements involved in locust olfaction
gene families in the desert locust Schistocerca gregaria
(2018) Jiang, Xingcong; Breer, Heinz
Locusts are remarkable insects due to their unique and potentially devastating phenotypic plasticity based on the local population density. While “solitarious” phase locusts avoid one another, “gregarious” locusts can form dense and highly mobile swarms, which have been feared as agricultural pests since ancient history. For this reason alone, locust biology has long been the object of intense scientific studies; moreover, from a purely scientific perspective it is of great interest to unravel the mystery underlying the phenotypic plasticity. The unique phase transition including the behavioral plasticity heavily relies on chemical communication by means of critical volatiles. It is therefore important to elucidate the mechanisms underlying locust chemosensory communication, including the identification of molecular elements involved in recognizing odorous compounds. Towards this goal, the desert locust Schistocerca gregaria, as a representative locust species, was investigated in this study. One of the key elements for recognizing odorous compounds are odorant binding proteins (OBPs). To gain insight into the repertoire of locust OBPs, genomic sequences encoding candidate OBPs from Schistocerca gregaria together with those from three other locust species were subjected to thorough comparative analyses. The results indicated that locust OBPs could be classified into several categories, namely, “classic OBPs”, “plus-C OBPs”, “minus-C OBPs” and “atypical OBPs” which reside in four major phylogenetic families (I to IV). With the aim to uncover distinct features of the various OBP types, the initial studies were concentrating on the conserved subfamilies I-A and II-A which comprise “classic OBPs”. The sequence analyses provided evidence for both common and subfamily-specific motifs as well as evolutionary clues based on the calculation of coden substitution rates, which suggested the effect of purifying selection pressure. The subfamily I-A comprised a much higher number of orthologous OBPs than subfamily II-A, which resulted in a distinct re-clustering patterns for subfamily I-A and subfamily II-A. Exploring the topographic expression pattern on the antennae revealed that OBPs of subfamily I-A were selectively expressed in sensilla basiconica and sensilla trichodea, whereas OBPs of subfamily II-A were restricted to sensilla coeloconica. Furthermore, cells expressing the subtype OBP1 were present in almost all sensilla basiconica and trichodea, whereas other subtypes were only present in subpopulations. The OBPs of subfamily II-A, were expressed in distinct subpopulations of sensilla coeloconica. Analyses of representative OBPs from the remaining phylogenetic subfamilies revealed that representative subtypes from subfamily III-A and III-B were expressed in sensilla chaetica, similarly the two representatives of subfamily I-B were also expressed in this sensillum type. The selective expression of these OBPs in sensilla chaetica was substantiated by analyzing the antennal tip, which comprises numerous sensilla chaetica. The “atypical OBP” OBP12, a representative of subfamily IV-A was found to be selectively expressed in a distinct subpopulation of sensilla coeloconica, while “plus-C OBP” OBP9, from subfamily IV-B, showed a unique expression pattern and seemed to be associate with all four sensillum types. The diversity and complex sensilla- and cellular-specific distribution implies distinct functional implications of OBP subtypes in the process of chemoreception.
Ontogenetic and individual patterns of volatiles in honeybee queens Apis mellifera and its significance for the acceptance of queens in honeybee colonies
(2008) Al Ali Alkattea, Raghdan; Bessei, Werner
Activities of honeybees Apis mellifera L. colony are coordinated by an effective communication network in which the queen plays a central role by controlling behavior and reproduction of workers through pheromones. Most pheromones are produced in the mandibular (QMP) and tergal gland and distributed over the queen?s cuticle. The acquisition of these pheromones from the cuticular body surface of the queen is performed by antennating and licking of the retinue workers. Workers of a colony are able to recognize their own queen. Foreign queens which are introduced without protection are normally killed by the workers. While a lot of work has been performed on the primer and releaser effect of certain queen pheromones, it is still unknown how the workers distinguish their own queen from foreign ones. The fact that queens can be exchanged successfully by protecting the foreign queen for some days demonstrates that workers are able to ?learn? their queen. It is likely that a certain chemical pattern of the cuticle (odor or taste) is finally responsible for the recognition and acceptance as ?own?. In this context, this work has three different objectives: - To better understand the bees? behavior to ?own? and ?foreign? queens and to quantify certain behavioral traits of the queen-workers interaction. - To study the learning ability for own and foreign queens by the use of the Proboscis Extension Reflex (PER) in order to have a tool for future tests of odorous compounds. - To compare the cuticular pattern of queens of different origin. In all three approaches, virgin and mated queens and queens of different kin relation to each other were reared and established in Kirchhainer nuclei colonies. These queens were compared due to the following hypothesis: If the workers perceive their own queen by a distinct smell and if closely related queens have a more similar chemical pattern on the cuticle, then a related foreign queen should be easier ?learned?/ accepted than a non related one. For this purpose, first a specific bioassay had to be developed and established to enable the record of workers behavior to the queen without an inhibition of the complex social interactions between queens and workers. This ?cage bioassay? consists of a small wooden box with a glass front, a wax comb, 30-40 worker bees and a queen. For the tests, the own queen of this mini-colony was removed and a foreign queen was introduced. For a period of about 2 hours certain aggressive and benign actions, respectively, of the workers toward the queen were recorded. In the first set of tests, queens of different kin relations were compared. The results showed, in general, an aggressive reaction against the introduced foreign queens. However, there were clear lower benign and stronger aggression behaviors against unrelated queens compared to the related ones. Some of the unrelated queens were even killed. However, these differences were only significant when virgin queens were exchanged but not when mated queens were used. Concerning the duration of the aggressive action of workers, aggression generally decreased between the beginning and the end of the test; again, this was significant only in the experiments with virgin queens. This indicates, that at least in virgin queens the individual recognition by the worker bees depends on a kin specific odorous pattern of the queen. The same types of queens used in the cage bioassays were used for the learning experiments. A classical olfactory conditioning (PER) of worker honeybees was applied by using a living queen as the source of odor. Hereby the queen was offered in a way that the worker bees could not touch the body surface. The gradual increase in the learning curves was a good indication that the workers are able to learn the queen?s odor and, therefore, can be used as a kind of ?biosensor?. After having learned a queen?s odor, the conditioned workers were tested by offering virgin and mated queens, respectively, with defined kin relation to the queen used for the conditioning before. The results revealed clear differences in the cues used for the ?learning? of individual mated and individual virgin queens, respectively. The workers could significantly discriminate between the learned odor of a mated queen and any other mated queen irrespective of the relatedness. In contrast, worker bees could not discriminate virgin queens from each other. As the worker could only use volatile substances for the associative learning, one can conclude the following: In virgin queens the volatile ?bouquet? is neither individual specific nor kin specific. In mated queens the bouquet has only an individual specificity. Probably, the huge amount of many volatile gland products (including the main component 9-ODA) makes each mated queen ?unique?. But as in the cage bioassays the worker could recognize whether an introduced virgin queen was related to the own queen or not, these recognition must depend on non volatile substances of the virgin queens cuticle which are perceived by licking. If learned and tested queens were of different mating status the worker bees could significantly discriminate between such individuals (except learned odor of mated queens/ tested odor of related virgin queens). This is not surprising because the GC-MS analysis confirmed the huge differences in the odorous pattern (and here mainly the volatile polar gland products) between virgin (= young) and mated (=elder) queens. From the same types of queens used for the cage bioassays and PER, queens? heads and abdomens were extracted in a solvent and the obtained extracts were analyzed using GC-MS. From the extracts of queen abdomens 32 substances (hydrocarbons and polar compounds) were identified and chosen to calculate the ?chemical distance? between queens of different kin relation (sister vs. unrelated) and between sister queens having different ages and mating status. For that purpose, a matrix of Nei-distances was applied as a measure for the similarity of different patterns. The results showed a significantly higher concordance in the chemical pattern within sister queens compared to non related ones. The ?chemical distance? increased from sister queens over half sister to non-related queens. Cluster analyses of the Nei distance and multidimensional scaling clearly confirmed the differentiation between unrelated queens and the similarity of sister queens. Using the same statistical methods, also a clear differentiation between queens of different ages and mating status could be demonstrated. The results presented in this work confirmed with 3 different approaches that workers are able to learn their own queen with different learning cues depending on the mating status of the queen. In virgin queens it could be demonstrated for the first time that the kin relation between different queens can be recognized, presumably by low or non-volatile substances. The chemical analyses confirmed that the cuticular pattern of queens could be used for the differentiation not only according to age but also according to kin.