Effect of extraction time and acid concentration on the separation of proglycogen and macroglycogen in horse muscle samples

The objective of this study was to determine whether the concentrations of proglycogen (PG) and macroglycogen (MG) in biopsy samples of horse muscle are influenced by extraction time or perchloric acid (PCA) concentration. In study 1, individual muscle-biopsy samples from 10 horses were divided into 4 parts each and then randomly subjected to 4 periods of extraction (10, 20, 60, or 120 min) with 1.5 M PCA. In study 2, individual muscle-biopsy samples from 6 horses were divided into 24 pieces each and then randomly subjected to 12 combinations of extraction time (10, 20, 30, or 40 min) and PCA concentration (0.5, 1.5, or 3.0 M). The results from study 1 indicated that PG and MG concentrations are affected only after extraction for 120 min; the PG concentration decreased significantly (P < 0.05), and the MG concentration increased (not significantly). In study 2, extraction in 3.0 M PCA yielded significantly lower PG and higher MG concentrations (P < 0.05) than extraction in 0.5 or 1.5 M PCA with each of the extraction times. The results of this study further support the existence of 2 glycogen pools and demonstrate that they are not an extraction artifact. The study also suggests that the 2 pools are stable during extraction over a range of extraction times and acid concentrations. However, if the exposure to acid is very long and, or, the acid concentration is high, some of the insoluble PG appears to be hydrolyzed and to enter the MG pool.     

Update on the diagnosis and treatment of disorders of calcium regulation.

The availability of PTH, iCa, PTHrP, and 25OHD assays for evaluation of calcium abnormalities in companion animals has been well received [table: see text] by clinicians and diagnosticians. Use of these assays has heightened awareness that some of these disorders are more common than originally thought. Also, there is added insight of alterations of calcium homeostasis as a consequence of other illness or environmental factors such as diet. Animal counterparts of other disorders of calcium metabolism in people are likely to be identified, and use of these assays should play a significant role. As already emphasized, the foundation of using [table: see text] these assays is first assessing whether the calcium abnormality is of a parathyroid-dependent or parathyroid-independent classification.     

Farmers’ participation and breeding for durable disease resistance in the Andean region

In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers participated in the selection of advanced materials, rather than finished cultivars. This paper describes this approach and reports experiences with farmers–breeders collaboration. As breeders involved farmers as participants, they learned more about the most important criteria of male and female farmers for preferred cultivars in the marginal environments of Andean cropping systems. This approach encouraged the use of locally adapted cultivars (often landraces), made the breeders less dependent on foreign materials, and has resulted in selection and development of new wheat, barley, common bean, quinoa, potato and maize cultivars. Breeding programmes based on crossing locally adapted cultivars followed by selection by the breeders in the early phases of the breeding programmes and by participatory selection with the farmers in the more advanced stages of the breeding programmes appeared successful. It became clear that breeders must be well acquainted with the farmer preferences such as the requirements for specific agronomic, storage, processing and marketing traits. Over a period of five years the centralized formal breeding approach predominantly based on material produced by the international institutes was replaced by decentralized breeding approaches based largely on local germplasm with extensive farmer participation.     

Inheritance of resistance to Phytophthora infestans in two diploid Mexican solanum species

Inheritance of resistance to Phytophthora infestans in the diploid Mexican species S. bulbocastanum and S. verrucosum appears to be quantitative. In these species there seems to be no clear distinction between a hypersensitive reaction to infection and one indicating a high degree of partial resistance. Sibbing or selfing apparently improves the degree of resistance in the progeny over that of the parents. S. verrucosum, a self-compatible species which shows little or no inbreeding depression after selfing, has especial advantages as a genetic tool and as a source of blight resistance, over S. bulbocastanum and other diploids.Contribution No. 119, Canada Dept. of Agriculture Research Station, Fredericton, New Brunswick, Canada     

Using multiple objective linear programming to evaluate multi-participant agroforestry systems

Multiple objective linear programming is used to evaluate a simulated two-participant maize/cassava/leucaena/teak agroforestry system. Examples using two different price ratios are presented along with possible methods to optimize the system with regard to the interests of the two profit seeking participants. A third example examines possible solutions to a system involving a profit seeking forester and a non-monetary subsistence farmer.

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Progmación Usando progmacion lineal con objectivos multiples se estudia un sistema agroforestal simulado de maiz, yuca, leucaena y teca, considerando dos participantes. Se presentan ejemplos usando dos niveles de pricios con metodos posibles paraq optimizar el sistema con respcto a intereses monetarios de los dos participantes. En un tercer ejemplo se examinan las soluciones posibles para el sistema, involucrando un silvicultor interesado en beneficios monetarios y un agricultor de subsistencia con interes no monetarios.

     

Zum Stand der Kenntnisse überProstephanus truncatus (Horn) (Col., Bostrichidae), einen gefährlichen Maisschädling in Afrika

Zusammenfassung Es wird ein gedrängter Überblick über die Lebens- und Schadensweise sowie Möglichkeiten der Bekämpfung des BostrichidenProstephanus truncatus gegeben, der nach seiner Einschleppung aus Mittelamerika in Afrika zu einem gefürchteten Maisschädling werde. Besonders zahlreich vermehrt er sich in belieschten Maiskolben, eine in ländlichen Regionen der Tropen häufig praktizierte Lagerform. Neuere Untersuchungen deuten darauf hin, daß der Käfer die Kolben an der Pflanze schon vor der Einlagerung befällt.Die Verluste in Maislägern mitP. truncatus-Befall liegen durchschnittlich 4fach über dem sonst üblichen Niveau. Schätzungen ergaben, daß eine landesweite Ausbreitung des Schädlings in Kenia, das durch seine direkte Nachbarschaft mit dem außerordentlich stark betroffenen Tansania potentiell gefährdet ist, zu einem Ernteverlust von mindestens DM 33 Mio. pro Jahr führen würde. Dieser Ausfall müßte durch entsprechend hohe Importe ausgeglichen werden.Zur Bekämpfung des Schädlings sind chlorierte Kohlenwasserstoffe und Phosphorsäureester ungeeignet. Pyrethroide wirken zum Teil sehr gut, sie sind aber für andere im Mais vorkommende Vorratsschädlinge nicht toxisch.Der Einsatz von Gegenspielern hatte bislang nur wenig Erfolg. Weder mit Prädatoren und Parasitoiden, noch mit Mikroorganismen und Protozoen konnten Erfolge bei der Populationsregulierung des Schädlings erzielt werden. Ob ein aus Mittelamerika eingeführter StutzkäferTeretriosoma nigrescens (Lewis) als Prädator auch in Afrika eingesetzt werden kann, ist zu prüfen. Auch Holzasche, mit der gegen andere Vorratsschädlinge eine recht gute Wirkung erzielt wurde, schützte den Lagermais nicht genügend gegenP. truncatus-Befall. Pflanzenöle, die gegen viele Schadinsekten erfolgreich verwendet wurden, sind bisher beim Großen Kornbohrer nicht getestet worden.

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On the knowledge ofProstephanus truncatus (Horn) (Col., Bostrichidae), a dangerous pest of maize in Africa

A view is given on the biology and distribution as well as on the chances of controlling the bostrichidProstephanus truncatus (Horn) in Africa. In the last decade this beetle has become one of the most important stored-product pests in the maize growing regions. It was imported from the tropical parts of middle America, where the larger corn borer caused little damage. At the beginning of the 70's the beetle appeared in West and East Africa with imported maize. Since that time it has expanded irresistibly through the whole area South of the Sahara. Apart from maize, which is its staple diet,P. truncatus destroys timber, leather and various artificial materials. Its reproduction is very high in corn cobs, which is the conventional form of storage in rural regions. Recent investigations reveal that the beetle attacks the cob on the plant before harvest has occurred.The losses in maize storages due toP. truncatus are four times higher than that experienced by all other forms of destructive pests. Estimations showed that a country-wide distribution of the pest in Kenya, originating from its badly affected neighbour Tanzania, cause a loss of harvest of at least DM 33 millions per year. This destruction must be balanced by correspondingly high imports.Chloride hydrocarbons and P-O-esters are unsuitable for pest control. Some pyrethroids are very effective, but are not toxie for the other stored-product pests also present in harvested corn.The use of opponents has proved unsuccessful. Neither predators and parasitoids nor microorganisms and protozoa have succeeded in regulation of the population. Whether the predatorTeretriosoma nigrescens (Lewis), imported from middle America, can be used as control organism in Africa, has yet to be proved. Wood ash which has shown good results obtained against other stored-product pests, did not protect stored corn sufficiently against the attack ofP. truncatus.Plant oils which were used successfully against other pests were not tested so far with the larger corn borer.

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