Genetic variation and structure of Solanum elaeagnifolium in Australia analysed by amplified fragment length polymorphism markers

Solanum elaeagnifolium is a weed of national significance in Australia. However, the genetic diversity of S. elaeagnifolium is poorly understood. Four amplified fragment length polymorphism primer combinations were utilised to investigate the genetic variation and structure of 187 S. elaeagnifolium individuals collected from 94 locations in Australia. High genetic diversity was found, with an average Jaccard's genetic similarity at 0.26. Individuals were assigned to two genetic clusters or considered as admixed according to their membership coefficient value (q) calculated by Bayesian model‐based genetic structure analysis. This suggested that Australian S. elaeagnifolium may have originated from two distinct gene pools. These results were further supported by principal co‐ordinates analysis. Large spatial groups of individuals assigning to these two gene pools were found in western Victoria and south‐western New South Wales (NSW) and northern NSW, which correlated well with the early records of S. elaeagnifolium in both regions. The high genetic diversity found here could add difficulties to effective control of S. elaeagnifolium across regions.     

Sympathoadrenal Neurochemistry and early weaning of swine.

Three litters of pigs were weaned at 21 days of age, and 3 others were left with the sow. Pigs were killed at 21, 23, 28, or 39 days of age. Weaned pigs exhibited anxiety, gastrointestinal dysfunction, and decreased rate of body weight gain. Plasma glucose or liver glycogen concentrations were not decreased by weaning. Adrenal gland weights and tyrosine hydroxylase (EC 1.14.3a), dopamine beta-hydroxylase (EC 1.14.2.1), phenethanolamine-N-methyl transferase (EC 2.1.1), and monoamine oxidase (EC 1.4.3.4) activities were increased after weaning. Adrenal catecholamine and cortisol levels and dopa decarboxylase (EC 4.1.1.26) and catechol-o-methyl transferase (EC 2.1.1.6) activities were not significantly altered, although some increases were indicated. Cranial cervical ganglionic choline acetyltransferase (EC 2.3.1.6) and tyrosine hydroxylase activities were increased after weaning. Weaning of swine at 21 days of age is a stressful experience, and many effects persist for at least 18 days; however, growth was no longer impaired 18 days after weaning.     

A Developmental Study of Sleep and Wakefulness in the Dog

Abstract— —The duration of wakefulness, quiet sleep and activated(REM) sleep was observed in dogs and recordings of EKG, EMG and respiration were taken at various ages during these different behavioral states. The greatest variations in autonomic functions occurred during activated sleep. With increasing age, the percentage of activated sleep decreased in proportion to wakefulness and quiet sleep, the latter increasing after 2 weeks of age. These observations are correlated with earlier studies on the development of GNS and behavior in this species, and their ontogenetic significance discussed. Résumé— —La durée de l'état de veille, de sommeil calme et de sommeil activé (REM) ont été verifiées chez des chiens et des enregistrements de la EKG, EMG et de la respiration ont été pris à différents âges pendant ces états diférents de comportement. Les plus grandes variations dans les fonctions autonomes survinrent pendant le sommeil activé. Avec la criossance de l'âge, le pourcentage du sommeil activé diminua en proportion avec l'état de veille et de sommeil calme, le dernier, croissant après l'àge de deux semaines. Ces observations sont en correlation avec des études anteér-ieures sur le dévéloppement du système nerveux central et le comportement de ces espèces; leur signification ontogénétique cst discutée. Zusammenfassung— —Die Dauer des Wachzustandes, ruhigem Schlaf, Schlaf mit Bewegungen (REM) wurde bei Hunden beobachtet und EKG-, EMG- und Respirationsaufzeichnungen während dieser verschiedenen Verhaltungsstaden wurden be iverschiedenen Altersgruppen gemacht. Die grössten Veränderungen der autonomischen Funktionen wurden während des Schlafes mit Bewegungen beobachtet. Mit zunehnemdem Alter wurde der Anteil des lebhaften Schlafes geringer zugunsten des Wachzustandes und ruhigen Schlafes. Der Letzterenahm nach den zwei ersten Lebenswochen zu. Diese Beobachtungen stimmem mit den früheren Beobachtungen über die Entwicklung des ZNS und Verhalten bei dieser Spezies überein, und ihre ontogenetische Bedeutung wird besprochen.     

Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets

The effects of grazed grass, grass silage, or concentrates on fatty acid composition and conjugated linoleic acid (cis-9, trans-11-18:2; CLA) concentrations of i.m. fat of steers fed to achieve similar carcass growth rates were investigated. Fifty steers were divided into 10 blocks based on body weight and assigned at random from within blocks to one of five dietary treatments. The experimental rations offered daily for 85 d preceding slaughter were 1) grass silage for ad libitum intake plus 4 kg of concentrate, 2) 8 kg of concentrate plus 1 kg of hay, 3) 6 kg of grazed grass DM plus 5 kg of concentrate, 4) 12 kg of grazed grass DM plus 2.5 kg concentrate, or 5) 22 kg of grazed grass DM. The concentration of polyunsaturated fatty acids (PUFA) in i.m. fat was higher (P < .05) for steers offered ration 5 than for those given any other ration. Decreasing the proportion of concentrate in the diet, which effectively increased grass intake, caused a linear decrease in the concentration of i.m. saturated fatty acids (SFA) (P < .01) and in the n-6:n-3 PUFA ratio (P < .001) and a linear increase in the PUFA:SFA ratio (P < .01) and the conjugated linoleic acid concentration (P < .001). The data indicate that i.m. fatty acid composition of beef can be improved from a human health perspective by inclusion of grass in the diet.     

Drought, snails, and large-scale die-off of southern U.S. salt marshes

Salt marshes in the southeastern United States have recently experienced massive die-off, one of many examples of widespread degradation in marine and coastal ecosystems. Although intense drought is thought to be the primary cause of this die-off, we found snail grazing to be a major contributing factor. Survey of marsh die-off areas in three states revealed high-density fronts of snails on die-off edges at 11 of 12 sites. Exclusion experiments demonstrated that snails actively converted marshes to exposed mudflats. Salt addition and comparative field studies suggest that drought-induced stress and grazers acted synergistically and to varying degrees to cause initial plant death. After these disturbances, snail fronts formed on die-off edges and subsequently propagated through healthy marsh, leading to cascading vegetation loss. These results, combined with model analyses, reveal strong interactions between increasing climatic stress and grazer pressure, both potentially related to human environmental impacts, which amplify the likelihood and intensity of runaway collapse in these coastal systems.