Untersuchungen über das Pollenschlauchwachstum von Pisum sativum und einiger mutanten

Summary When the pollen tubes of Pisum sativum (initial line) and of its mutants are grown on a standard medium containing only sucrose, boric acid and agar-agar, no difference in maximum length was observed. But, while pollen tubes of the initial line took nine hours to reach this length, pollen tubes of the mutants needed only six hours. Growth seems to be faster in pollen tubes of the mutants than in those of the initial line.Further investigations examined the influence of twenty-one amino acids on pollen tube growth. With the initial line, these substances can be classified into three groups: those that promote pollen tube growth; those which have no influence upon its growth; and those which reduce its growth. The amino acids of each group are characterized by special structural properties. Those amino acids which accelerate pollen tube growth of the initial line show variable effects on the pollen tubes of the mutants. In some cases the same behaviour of pollen tubes can be observed whether amino acids are added or not, in others the addition of amino acids has a positive effect on pollen tube growth, though less than on pollen tubes of the initial line, and in a single case the addition of an amino acid is followed by a negative effect on growth.     

Two discrete DNA replication intermediates are formed in melphalan-treated cells

Regulated and nonregulated phosphorylases were found to catalyze in a slow, orthophosphate dependent reaction the direct transfer of the glucosyl residue from α-D-glucosyl fluoride to an oligosaccharide primer. The enzyme catalyzed formation of the glucosyl residue requires stereospecific protonation of α-D-glucosyl fluoride by a Brønstedt acid. The results are interpreted by a mechanism whereby phosphate acts as a proton shuttle and the cofactor pyridoxal 5′-phosphate is required to promote the acid-base function of phosphate.     

Die Sozialisation beim Rosenk?pfchenAgapornis roseicollis

Zusammenfassung Junge Rosenköpfchen,Agapornis roseicollis, verlassen durchschnittlich mit 42 Lebenstagen zum erstenmal die Nisthöhlen und werden danach noch etwa zwei Wochen vorwiegend vom Vater gefüttert. Fütterungen treten gelegentlich auch zwischen Geschwistern auf. Die Jungvögel haben mit den Eltern und Geschwistern bis Anfang des vierten Lebensmonats Kraulkontakte. Noch im Jugendkleid, zumeist im Alter von 65 bis 90 Tagen, verpaaren sich Rosenköpfchen mit einem anderen Jungvogel, bevorzugt aus einer anderen Familie und anderen Geschlechts. Diese Jugendpaare bleiben stabil bis über die Geschlechtsreife hinaus. Bestimmte soziale Verhaltensweisen (Sexualverhalten, Kraulen, Kontaktsitzen) werden nur mit dem Partner ausgeführt.

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Socialization of the Peach-faced Lovebird,Agapornis roseicollis

Summary Young Peach-faced Lovebirds, leave their nest-box on an average with 42 days of age. They are still fed for about another two weeks, mainly by the father. Feeding interactions sometimes also occur between siblings. The young undergo allopreening interactions with parents and siblings until the beginning of the fourth month of life. While still in juvenile plumage, usually between 65 und 90 days of life, they form a pair-bond with another young bird, preferably from another family and the other sex. These pairs remain stable beyond sexual maturation. Several social behaviour patterns (sexual behaviour, allopreening, contact sitting) are restricted to the mate.

     

Reproductive and Stress Response Hormones of the Critically Endangered Southern Muriqui (Brachyteles arachnoides: Atelidae) Under Captive Conditions

International Journal of Primatology - The Convention on Biological Diversity and the International Union for Conservation of Nature emphasize that ex situ conservation efforts are unavoidable....     

Monoarticular antigen-induced arthritis leads to pronounced bilateral upregulation of the expression of neurokinin 1 and bradykinin 2 receptors in dorsal root ganglion neurons of rats

This study describes the upregulation of neurokinin 1 and bradykinin 2 receptors in dorsal root ganglion (DRG) neurons in the course of antigen-induced arthritis (AIA) in the rat knee. In the acute phase of AIA, which was characterized by pronounced hyperalgesia, there was a substantial bilateral increase in the proportion of lumbar DRG neurons that express neurokinin 1 receptors (activated by substance P) and bradykinin 2 receptors. In the chronic phase the upregulation of bradykinin 2 receptors persisted on the side of inflammation. The increase in the receptor expression is relevant for the generation of acute and chronic inflammatory pain.     

Physiological and behavioral indices of short-term stress in wild vicuñas (Vicugna vicugna) in Jujuy Province,Argentina

The management of wild vicuñas can trigger a stress response that may compromise welfare. In Santa Catalina, Jujuy Province, Argentina, indices of short-term stress associated with capture, handling, and shearing were studied in 105 wild vicuñas (Vicugna vicugna). The study included 2 groups (n = 59 and n = 46) of wild vicuñas captured in 2 consecutive days. Independent variables analyzed included sex, restraint time, and groups. Cortisol, creatine kinase, glucose, white blood cells, temperature, heart rate, and respiratory frequency were higher than published values. Respiratory rate increased during handling and correlated with holding time and group size, while heart rate decreased. Packed cell volume was higher in females. Cortisol concentrations differed between restraint groups and sex and inversely correlated with agonistic behavior. The most common behavior was increased vigilance. Sternal recumbency increased over holding time. During handling procedures, frequency of sudden movements like kicking and attempts to stand increased as restraint time increased. Females vocalized more than males. In conclusion, the methods used triggered measurable changes suggestive of short-term stress that appeared to be physiologically tolerated by the vicuñas.     

Development of a Differential Set for the Race analysis of Puccinia hordei Otth.

Investigations for the race analysis of P. hordei (location Cologne, W.-Germany) showed, that most of the resistant genotypes in the International differential set with Pa₁ to Pa₈ were ineffective for that purpose. Out of 80 selected barley genotypes with different degree of resistance against the field-collection RG 1975 hosts with a strongly differentiating effect were chosen. This was done using three parameters: mean resistance x?w, its standard deviation x?w and the range z. They were calculated from evaluating the reaction types of 80 barley genotypes infected with 116 single-pustule lines of barley brown rust. Eight hosts with strongly differentiating reactions towards the 116 rust lines were composed into a differential set, which could characterize the heterogeneity of the Cologne P. hordei-population essentially better and more precisely than the International differential set.     

Social influences on estrogen excretion and ovarian cyclicity in saddle back tamarins (Saguinus fuscicollis)

The effects of different social living conditions on estrogen excretion and on the ovarian cycle of saddle back tamarins were investigated. Urinary estrogens were monitored as indices of ovarian cyclicity in groups of adult females living under the following experimental conditions: (1) five parous females, each living with an adult castrated male (in one of the females plasma estradiol and progesterone were also measured); (2) five adult daughters living with their families. Each daughter was then removed from her family and paired with a vasectomized male. After pairing, scent marks collected from the family were introduced daily to one of the daughters and her mate. Scent exposure was then discontinued and hormone excretion measured for several weeks. The remaining four daughters were not exposed to family scent. The females living with castrated males showed urinary estrogen cycles of an average length of 17.5 ± 1.0 days. The plasma estrogen cycle was of the same length. The females studied under condition 2 showed low, noncycling estrogen levels while living in their families. They responded to pairing with an increase in the level of urinary estrogens, and four out of five showed regular estrogen cyclicity. The fifth female exposed to family scent marks after pairing also showed an increase in urinary estrogens. However, as long as scent transfer was maintained, no cycle was observed. Estrogen excretion increased again, and cyclicity commenced when scent transfer was discontinued. It is concluded that ovarian estrogen production is suppressed and cyclicity does not occur as long as daughters live in their families. Release from suppression and perhaps stimulation by the male cause a rapid increase in estrogen levels and the onset of cyclicity. Chemical stimuli produced by the family, perhaps particularly by the mother, may be involved in reproductive suppression.