In. vitro evaluation of corpus luteum function of cycling and pregnant rhesus monkeys: Progesterone production by dispersed luteal cells

Corpus luteum function in the cycling and the pregnant rhesus monkey (Macaca mulatta) was evaluated through short term $\text{in vitro}$ studies of progesterone production by suspensions of collagenase-dispersed luteal cells in the presence and absence of exogenous gonadotropin (human chortonic gonadotropin, HCG). Cells from mid-luteal phase of the menstrual cycle secreted progesterone, as measured by accumulation of this hormone in the incubation medium, and responded to the addition of 100 ng HCG/ml with a marked increase in progesterone secretion above basal level ($\text{63.7 ± 13.1}\text{versus}\text{24.7 ± 5.5}\text{ng progesterone}\text{/}\text{ml}\text{/5 × 10}{}^4\text{cells}\text{/ 3}\text{hr}\text{,}\text{X}\text{± S.E.,}\text{n}\text{= 6;}\text{p}\text{< 0.05}$). However, luteal cells from early pregnancy (23–26 days after fertilization) secreted significantly less progesterone than cells of the non-fertile menstrual cycle (3.6 ± 2.4 versus 24.7 ± 5.5 ng/ml/5 × 10⁴ cells/3 hr, n = 3; p < 0.05) and did not respond to HCG with enhanced secretion. By mid-pregnancy (108–118 days gestation) luteal cells exhibited partially renewed function, and near the time of parturition (163–166 days gestation) basal and HCG-stimulated progesterone secretion (30.2 ± 5.6 and 63.0 ± 13.0 ng/ml/5 × 10⁴ cells/3 hr, respectively; n = 3) was equivalent to that of cells from the luteal phase of the non-fertile menstrual cycle. The data suggest that following a period around the fourth week of gestation, when steroidogenic activity is markedly diminished, the corpus luteum of pregnancy progressively reacquires its functional capacity and at term exhibits gonadotropin-sensitive steroidogenesis similar to that of the corpus luteum of the menstrual cycle.     

Novel Production Protocol for Small-scale Manufacture of Probiotic Fermented Foods

A novel dried bacterial consortium of Lactobacillus rhamnosus yoba 2012 and Streptococcus thermophilus C106 is cultured in 1 L of milk. This fresh starter can be used for the production of fermented milk and other fermented foods either at home or at small-scale in rural settings. For the fresh starter, 1 L of milk is pasteurized in a pan that fits into a larger pan containing water, placed on a source of heat. In this water bath, the milk is heated and incubated at 85 °C for 30 min. Thereafter, the milk is cooled down to 45 °C, transferred to a vacuum flask, inoculated with the dried bacteria and left for at least 16 hr between 30 °C and 45 °C. For the purpose of frequent home production, the fresh starter is frozen into ice cubes, which can be used for the production of small volumes of up to 2 L of fermented milk. For the purpose of small-scale production in resource-poor countries, pasteurization of up to 100 L of milk is conducted in milk cans that are placed in a large sauce pan filled with water and heated on a fire at 85 °C for 30 min, and subsequently cooled to 45 °C. Next, the 100 L batch is inoculated with the 1 L freshly prepared starter mentioned before. To assure an effective fermentation at a temperature between 30 and 45 °C, the milk can is covered with a blanket for 12 hr. For the production of non-dairy fermented foods, the fresh starter is left in a cheese cloth for 12 hr, and the drained-off whey can be subsequently used for the inoculation of a wide range of food raw materials, including vegetables and cereal-based foods.     

ZUR SUCHFÄHIGKEIT DER EILARVEN VON APHIDOLETES APHIDIMYZA (DIPTERA: CECIDOMYIIDAE)

Zusammenfassung Die Eilarven der aphidophagen Gallmücke Aphidoletes aphidimyza tasteten auf der Suche nach ihrer ersten Beute im Schnitt nur 0.76 cm² der Blattfläche ab, bevor sie verhungerten. Aus dem Sucherfolg bei unterschiedlicher Blattlausdichte ergab sich aber, daß sie die Beute auf einem Areal von 2,70 cm² erfaßten, also offenbar bereits auf kurze Entfernung wahrnahmen. Durch Festkleben von Blattläusen in verschiedener Richtung und Entfernung von schlupfreifen Eiern ließ sich zeigen, daß die Attraktivität der Beute für die schlüpfenden Larven von Größe und Distanz abhängig ist. Dabei traten jedoch Unterschiede im Verhalten der Larven auf, deren Ursache noch unbekannt ist. Die populationsdynamischen Folgen der Wahrnehmung von Beute auf Distanz werden diskutiert.

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Summary Fecundity and mortality of the aphidophagous midge Aphidoletes aphidimyza are dependent in various ways on prey density. The first period of life is the most crucial one: Without food the newly hatched larvae covered only an average distance of 63 mm. Consequently, the larvae could find their prey within an area of 0.76 cm², if aphids were recognized only by touch. From the percentage of successful searching with different aphid densities, however, it was calculated that the larvae discovered their prey within an area of 2,70 cm². Hence, prey is already perceived at a short distance and the probability of survival is correspondingly enhanced.In the absence of prey nearly two-thirds of the newly hatched larvae crawl from the start toward the direction indicated by the anterior pole of the egg, the others go sidewards or backwards. If single peach aphids (Myzus persicae) are glued to the leaf surface near the egg, some larvae turn toward them. But only the number of larvae crawling forward is correspondingly reduced; crawling in other directions is not markedly influenced.The attractiveness of prey is dependent on its size and distance. At a distance of 5 mm young peach aphids had only a weak influence. On the other hand, a considerable part of the newly hatched larvae appeared to be not influenced at all by the prey.The causes of the different behaviour and the mode of perception are the objects of further investigation.

     

Apanteles Pieridis (bouché) (Hym., Braconidae), ein Parasit vonAporia Crataegi (L.) (Lep., Pieridae)

Ohne Zusammenfassung     

Transformation of Folate-Consuming Lactobacillus gasseri into a Folate Producer

Five genes essential for folate biosynthesis in Lactococcus lactis were cloned on a broad-host-range lactococcal vector and were transferred to the folate auxotroph Lactobacillus gasseri. As a result L. gasseri changed from a folate consumer to a folate producer. This principle can be used to increase folate levels in many fermented food products.     

Experimentelle untersuchungen über material-kompensation bei der entwicklung von insekten

Ohne Zusammenfassung     

Habitat diversity and fish assemblages in an African river basin (Nyagui River, Zimbabwe)

Little is known about the ecology of stream fishes in Zimbabwe and this study investigated fish communities in the Nyagui River basin and is one of the first to examine the relationship between fish assemblages and habitat diversity in Zimbabwe. Fourteen sampling stations were, for convenience, divided into three groups; upper (>1400 m above sea level), middle (1000–14000 m) and lower stations (<1000 m). A total of 24 species were collected, four of which were introduced, and the species composition differed according to the location of the stations. Species that favoured running water and/or rocks were generally absent from the upper stations, reflecting the fact that they were mostly sandy‐bottomed and still. Diversity and relative abundance increased in the mid‐ and low‐altitude stations, which were rockier and faster flowing. Both species diversity and relative abundance increased with the catchment area above each station, which was attributed to increased habitat diversity in larger streams. This view was supported by a strong correlation between habitat diversity and catchment area, and between habitat diversity and species richness and relative abundance. At present, the Nyagui system is relatively unregulated but the Kunzvi Dam, presently under construction, will change this situation and species diversity is likely to decrease owing to the loss of rheophilic species while other groups, notably cichlids and introduced species will increase.