The chemistry of thujone: I. Synthesis of insect juvenile hormone analogs via wittig coupling

Syntheses of the C₈ and C₁₀ olefinic units cis- and trans-5-ethyl-1-iodo-hex-4-enes and cis- and trans-7-ethyl-3-iodo-oct-6-enes are described. The Wittig coupling of such units with derivatives of α- and β-thujaketonic acids to give analogs of insect juvenile hormones is discussed.     

Phorbol ester TPA inhibits the stimulation of bumetanide-sensitive Na+/K+/Cl- transporter by different mitogens in quiescent BALB/c 3T3 mouse fibroblasts

In this study we examined the effect of the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the bumetanide-sensitive Na+/K+/Cl- transporter in quiescent BALB/c 3T3 cells. We have shown that exposure of quiescent BALB/c 3T3 cultures to phorbol ester did not inhibit the basal bumetanide-sensitive Rb+ influx or efflux. In fact, at high concentration (100 ng/ml), TPA slightly stimulated the bumetanide-sensitive Rb+ influx and efflux. However, when the quiescent cultures were stimulated by serum or by defined growth factors, the stimulated fraction of the bumetanide-sensitive Rb+ influx was drastically inhibited by exposure of the cells to the phorbol ester TPA. Based on the above findings, we propose that activation of protein kinase C by the phorbol ester TPA does not inhibit the Na+/K+/Cl- cotransport activity; however it does suppress only the growth-factors-stimulated fraction of the cotransport in quiescent BALB/c 3T3 cells. These data propose that activation of kinase C has a regulatory feedback effect on the stimulation of the Na+/K+/Cl- cotransport activity by growth factors.     

Identification of human hookworm in failed-treatment cases using Chinese hamsters (Cricetulus griseus) and scanning electron microscopy

An attempt was made to identify the human hookworm involved in failed-treatment cases using abnormal hosts and scanning electron microscopy. Thirty-seven, 2 to 6 month old Chinese hamsters (Cricetulus griseus) from a closed, outbred, conventional colony, were each given between 20 and 120 filariform larvae per os. The larvae were cultured from faeces from mebendazole (Vermox) 500 mg single-dose, failed-treatment cases living in the lowveld farming area of the Transvaal Province, South Africa. About 60 to 78 days after inoculation, the animals were killed and adult worms were removed from their small intestines. Eleven (30%) of the 37 hamsters harboured a total of 31 adult worms (19 males and 12 females), while 26 hamsters were refractory to infection. The greatest number of worms recovered from a single animal was six. A total of 27 worms (17 males and 10 females) were subjected to examination by scanning electron microscopy. Micrographs showed male and female worms to be morphologically all of the Necator americanus species, as identified by a pair of ventral and dorsal cutting plates, a dorsal tooth and the fused terminus of spicules in the male bursa. The transverse cuticular striations were distinct and smooth. Several points of interest arose from the results of this study and are discussed.     

Vorkommen des Auerhuhns (Tetrao urogallus major C. L. Brehm, 1831) am Athos (Greichenland)

Summary At the Mount Athos the Capercaillie is spread in the montane high forests at an altitude between 1140 m and 1340 m above sea level. This isolated occurrence at the southern boundary of the species area and 140 km to the south of the breeding place in the Rhodope Mountains is the southernmost occurrence recorded so far. In former times, the Capercaillie presumably was widespread in the mountain forests of Central and Northern Greece.     

Territorialit?t und Brutbiologie der FeldlercheAlauda arvensis in einer intensiv genutzten Agrarlandschaft

Zusammenfassung In einer intensiv landwirtschaftlich genutzten Fläche des schweizerischen Mittellandes wurden 1983–1987 vier Feldlerchenaggregationen mit maximal 39 Brutpaaren untersucht. Die Tradition (Ortstreue) bestimmte in erster Linie die Revierwahl und das Verteilungsmuster. Die Reviere waren mit ha sehr groß; ihre Größe korrelierte negativ mit der Anzahl Parzellen pro Fläche und der Kulturendiversität. Die Nutzung des Ressourcenangebots (Nistplatz, Nahrung, Schutz) war abhängig von den Fortbewegungsmöglichkeiten. In großparzellig strukturierten Flächen mit geringer Kulturendiversität kam es häufig zu Revierverschiebungen und Reviervergrößerungen. Die Feldlerche versucht, im Laufe der Brutperiode den Getreideanteil im Revier zu verkleinern und Kulturen wie Rüben, Kartoffeln und auch Mais zu aquirieren. Die Nistplatzwahl zeigte eine deutliche Präferenz für alle nicht zu dicht stehenden, grasartigen Kulturen (Weizen, Hafer, Fettwiese). Eine Vegetationshöhe von 15–25 cm und eine Bodenbedeckung von 20–50 % bieten optimale Bedingungen für den Nestbau. 51 % aller Nester wurden in der Fettwiese angelegt, 20 % im Winterweizen und 18 % im Mais. Je nach Bewirtschaftungsart brüteten die im Mittel 2,4–2,8mal pro Brutsaison. Die Schlüpfrate von 220 Gelegen betrug 0,58. 44 % der geschlüpften Jungvögel verließen das Nest. Der Bruterfolg (nestverlassende Junge/gelegte Eier) lag bei max. 25 %. Dem Fütterungsverhalten der Altvögel nach zu schließen, wurden maximal 50 % der nestverlassenden Jungen flügge. Durchschnittlich war mit 0,9 flüggen Jungen pro Brutpaar und Jahr zu rechnen. Brutverluste waren kulturspezifisch und daher in erster Linie vom Neststandort abhängig.

---

Territoriality and breeding biology of Skylark (Alauda arvensis) in an intensively farmed area in Switzerland

Summary In 1983–1987 four plots (total surface 307 ha) with up to 39 breeding pairs were studied in an area of intensive cultivation in the Swiss Lowlands (390 m asl). Distribution pattern and selection of territories are determined by a strong site tenacity of the birds. The size of territories averaged 3,3±0,9 hectares. It correlates negatively with the number of different crops per unit area and the diversity of cultures.The mobility within the vegetation determined which types of farmland ressources may be used for nesting, feeding and cover. Shifts of territories and attempts to enlarge them were frequent in areas of large plots with low crop diversity. During the season, Skylarks tried to reduce the proportion of cereal fields within their territory and to gain plots planted with sugar-beet, potatoes and corn.Their choice of nesting sites showed a strong preference for less dense grass crops such as wheat, oat or meadows. Optimal conditions for nest sites were in fields with a vegetation height of 15–25 cm and a ground coverage of 20–50 %. 51 % of 220 nests were constructed in heavily manured meadows, 20 % in winter wheat fields and 18 % in corn fields. Females bred on average 2,4–2,8 times per breeding season, depending on the type of cultivation (agriculture, husbandry). Hatching rate was 58 % out of 220 clutches, and 44 % of the hatched young left the nest. Maximum breeding success (i. e. young birds leaving the nest/number of eggs laid) was thus maximal 25 %. Observations of parental feeding behaviour suggest that a maximum of 50 % of the young larks which leave the nests survive to the age of fledging. It is estimated that 0,9 fledglings are raised per breeding pairs and year. Losses of broods vary according to farming practises in the different crops and therefore are largely depending on nesting sites.

     

Na+-dependent,potential-sensitive l-ascorbate transport across brush border membrane vesicles from kidney cortex

l-Ascorbate is taken up into brush border vesicles from kidney cortex of rat, rabbit and guinea pig by an efficient, Na⁺-dependent and potential-sensitive transport process. This uptake shows saturation ($\text{K}{}_{\mathrm{<mtext>m</mtext><mtext>:0.1–0.3\; mM</mtext>}}$) and is strongly stimulated by low concentrations of N₃^?. Erythorbate (d-isoascorbate) seems to be another, but poorer, substrate of the same transporter.     

Degradation of 4-chlorophenylacetic acid by a Pseudomonas species.

Pseudomonas sp. strain CBS3 was able to utilize 4-chlorophenylacetic acid as the sole source of carbon and energy. When this strain was grown with 4-chlorophenylacetic acid, homoprotocatechuic acid was found to be an intermediate which was further metabolized by the meta-cleavage pathway. Furthermore, three isomers of chlorohydroxyphenylacetic acid, two of them identified as 3-chloro-4-hydroxyphenylacetic acid and 4-chloro-3-hydroxyphenylacetic acid, were isolated from the culture medium. 4-Hydroxyphenylacetic acid was catabolized in a different manner by the glutathione-dependent homogentisate pathway. Degradation enzymes of both of these pathways were inducible.     

Structure of T4 polyheads: II. A pathway of polyhead transformations as a model for T4 capsid maturation

We have studied the aberrant tubular polyheads of bacteriophages T4D and T2L as a model system for capsid maturation. Six different types of polyhead surface lattice morphology, and the corresponding protein compositions are reported and discussed. Using in vitro systems to induce transformations between particular polyhead types, we have deduced that the structural classes represent successive points in a transitional pathway. In the first step, coarse polyheads (analogous to the prohead τ-particle) are proteolytically cleaved by a phagecoded protease, a fragment of the gene 21 product. This cleavage of P23 to P23¹ induces a co-operative lattice transformation in the protein of the surface shell, to a conformation equivalent to that of T2L giant phage capsids. These polyheads (derived either from T4 or T2L lysates) can accept further T4-coded proteins. In doing so, they pass through intermediate structural states, eventually reaching an end point whose unit cell morphology is indistinguishable from that of the giant T4 capsids. At least one protein (called soc (Ishii & Yanagida, 1975)) is bound stoichiometrically to P23¹ in the end-state conformation. The simulation of several aspects of capsid maturation (cleavage of P23 to P23¹, stabilization, and lattice expansion) in the polyhead pathway suggest that it parallels the major events of phage T-even capsid maturation, decoupled from any involvement of DNA packaging.     

Folding and capsomere morphology of the P23 surface shell of bacteriophage T4 polyheads from mutants in five different head genes

Mutants in five different “head formation” genes (20, 22, 24, 40, IPIII)² of bacteriophage T4 produce polyheads. “Coarse” polyheads, which contain uncleaved P23, constitute over 90% of these tubular particles in fresh lysates. Using optical diffraction and filtration, we show that the pseudo-hexagonal net and the capsomere morphology are common to all coarse polyheads, regardless of genetic origin or polyhead diameter. Micropolymorphism is exhibited in each genetic class with respect to the cylindrical folding of the hexagonal net. We find that the frequency distribution of the diameters and pitch angles is significantly different for polyheads made by mutants affecting either of the major prohead core proteins (IPIII and P22). In every case, the foldings differ from the unique folding characteristic of giant phage capsid, suggesting that the assembly error responsible for producing polyheads instead of proheads involves a misdirection in arranging the P23 shell. By analysing the properties common to the various structures which may be formed out of this net (single-layered polyheads, multi-layered polyheads, proheads), we find that the P23 molecules possess form-determining specificity in terms of an intrinsic curvature of the capsomere bonding. These observations are discussed within the context of form determination of the phage prohead (τ-particle) and of its subsequent conservative maturation to the head of the infective wild-type phage.