Characterisation of<Emphasis Type="Italic">fusarium graminearum</Emphasis> and<Emphasis Type="Italic">F. culmorum</Emphasis> isolates by mycotoxin production and aggressiveness to wheat

A total of 27Fusarium culmorum isolates from Germany and 41F. graminearum isolates from Kenya were investigated for aggressiveness and mycotoxin production on wheat ears. In addition, ergosterol content of the kernels from ears inoculated withF. graminearum was determined and theF. culmorum isolates were tested for mycotoxin productionin vitro. For both pathogens, isolates markedly differed in aggressiveness. 59% and 37% of theF. culmorum isolates produced NIV and DON, respectively,in vivo andin vitro. The DON-producing isolates also produced 3-acDONin vitro. The more aggressive isolates produced mainly DON while the less aggressive isolates produced mainly NIV. 12% and 85% of theF. graminearum isolates produced NIV and DON, respectively. The highly aggressive isolates produced higher amounts of DON, aggressiveness being highly correlated to DON content in the kernels. NIV-producing isolates were less aggressive. Ergosterol content of kernels was moderately correlated to aggressiveness but highly correlated to DON content. Disease severity was associated with kernel weight reduction.     

Observations on root and stem contraction in cycads (Cycadales) with special reference to Zamia pumila L.

Cycads are pachycaulous plants possessing either aerial and columnar (arborescent) stems or subterranean and tuberous fleshy stems. In some taxa, such as Zamia pumila and Stangeria eriopus , the vertical shoots are subterranean; the shoot apex usually remains underground even though new shoot increments arc added as a result of leaf development. The external surface of these stems has a winkled appearance in the distal regions and the height of the leaf scars decreases basipetally This is because both the fleshy tap root and the stem contract, pulling the shoot underground. This contraction results from the collapse of horizontal rows of cells in both the pith and cortex. The vascular cylinder which appears straight in longitudinal sections becomes sinuously distorted as this collapse of cells occurs.     

Studies in the Physiology of Parasitism: XVI. Effect of the Condition of Potato Tissue, as modified by Temperature and Water-content, upon Attack by Certain Organisms and their Pectinase Enzymes

1.Certain bacteria which are normally termed saprophytic, viz.Bacillus subtilis and B. megatherium, are able to parasitizeliving potato tissue at a suitably high temperature or whenthe tissue is injected with water. 2.Within the group of four bacteria tested, there is a correlationbetween capacity to attack potato tissue and amount of pectinaseenzyme excreted under standard conditions. 3.A qualitative difference between the pectinase enzymes ofBotrytis cinerea and Bacterium carotovorum has been demonstrated.Preparations of the bacterial enzyme, which when tested on turgidpotato discs of standard thickness were found to be weaker thanBotrytis enzyme, were able to attack normal (subturgid) potatotissue, whereas the Botrytis enzyme failed to do so. No explanationof this difference is yet forthcoming. It does not seem to restupon osmotic differences between the two enzymic preparations. 4.Rate of diffusion appears .to be a limiting factor in theattack of potato tissue by preparations of pectinase enzyme.     

Diet of the Critically Endangered Brown Spider Monkey (Ateles hybridus) in an Inter‐Andean Lowland Rainforest in Colombia

Brown spider monkeys (Ateles hybridus) are one of the least known and more threatened primates in the Neotropics. Recognized as a species about a decade ago, field studies on these endangered primates have mainly focused on estimating local population densities. Since 2006, we habituated a group of wild brown spider monkeys at Serranía de Las Quinchas, Colombia, and studied their feeding ecology during 2.5 years using focal “subgroup” sampling, and conducted phenological surveys in order to estimate habitat‐wide fruit availability. Based on 847 hr of behavioral follows, brown spider monkeys spent approximately 25% of their time in feeding activities, and fed from fruits and leaves on at least 123 plant species. Ripe fruits were the most important item in the diet of A. hybridus at Las Quinchas comprising 92% of their feeding time. Probably due to the minor variation in the monthly proportion of fruits in brown spider monkey's diet throughout this study, there was no relation between habitat‐wide fruit availability and the proportion of fruit included in their monthly diet. The diet of brown spider monkeys at Las Quinchas is toward the high end of fruit intake, even within other wild spider monkeys’ populations, suggesting that these endangered primates might also be facing the challenges of being a large bodied fruit specialist under a regional scenario of habitat loss and fragmentation. Am. J. Primatol. 74:1097‐1105, 2012. © 2012 Wiley Periodicals, Inc.