Aerobic Metabolism of Brochothrix thermosphacta Growing on Meat Surfaces and in Laboratory Media

Acetoin and acetic, isobutyric and isovaleric acids are major end-products, and important components of the spoilage odours, of Brochothrix thermosphacta growing aerobically on meat surfaces or in tryptone-based medium containing glucose, ribose or glycerol. Acetoin and acetic acid are probably derived entirely from the carbohydrates and isobutyric and isovaleric acids from valine and leucine respectively. Glucose and pH are both important factors in controlling the relative amounts of end-products, low glucose and near neutral pH favouring fatty acid formation, high glucose and lower pH values favouring acetoin formation.     

Influence of Photoperiod, Daylength, and Feeding Schedule on Tadpole Growth and Development

The metamorphic rate of Rana pipiens tadpoles was studied under different photoperiods, daylengths, and feeding schedules. Tail resorption and hindlimb growth and development induced by immersion in 30 μg/l thyroxine (T₄) were accelerated under longer photoperiods and continuous light when 6L: 18D, 12L: 12D, 18L: 6D, and 24L regimes were compared. Constant light exposure did not produce faster development than an 18 hr photoperiod, and initially was less effective. The rate of spontaneous and T₄-induced metamorphosis was greater the shorter the day on 9L:9D, 12L: 12D, or 15L: 15D cycles, although all groups received the same overall amount of light, but in different dosages. When feeding schedule but not the LD cycle was varied, groups of tadpoles fed on 18, 24, or 30 hr regimes showed no differences in growth and development rate on 19L: 5D, and only random variations under continuous light. Differences in metamorphic rate on 18, 24, or 30 hr days are not due to the feeding schedules, but to the LD cycles. From these experiments we conclude that illumination, particularly the length and frequency of the photoperiod, affects the utilization of T₄. Development rates independent of the total amount of illumination, but related to daylength and light schedule, suggest interaction of light with an endogenous timing mechanism.     

In vitro screening of coffee genotypes for resistance to coffee berry disease (Colletotrichum kahawae)

An in vitro protocol was developed to screen Coffea arabica genotypes for resistance to coffee berry disease caused by Colletotrichum kahawae. Initially, cultural conditions which influenced the growth of isolates of C. kahawae on agar media suitable for callus growth were determined. The growth of the fungus on the callus derived from susceptible and resistant genotypes was then assessed. This ensured that no detrimental competition for nutrients between the pathogen and the calli occurred. Optimisation of the concentration of the phytohormones added to the media, the temperature and incubation period were found to be important in the expression of differential responses of calli to inoculation with the pathogen as detected by measurement of hyphal growth. The screening of calli of nine C. arabica genotypes showed that this method identified genotypes highly resistant or susceptible to the disease and was sufficiently sensitive to distinguish those genotypes with moderate or low resistance.     

Bud-eating by bullfinches, Pyrrhulapyrrhula in relation to the chemical constituents of two pear cultivars

Damage to pear trees of the cultivars Conference and Doyenne du Cornice caused by Bullfinches feeding on the flower buds was measured during January-April 1981. Bud-eating was concentrated on trees near woodland, and occurred at a steady rate within each row, though progressively more rows were attacked. Levels of total soluble protein, free amino acids, starch, glyeeride-glycerol, fructose, glucose and phosphorus were low until mid March, when the amounts per bud (and concentrations of starch and total soluble protein) rose sharply, coinciding with an increase in the size of buds. Sucrose did not occur at detectable levels. Conference buds contained significantly higher concentrations of fructose and free amino acids than Cornice. The implications for understanding bullfinches' bud-feeding habits are discussed.     

Development of microsatellites for the invasive riparian plant Impatiens glandulifera (Himalayan balsam) using intersimple sequence repeat cloning

Impatiens glandulifera (Himalayan balsam) is an invasive riparian plant species that can outcompete native perennials. Population genetic data on dispersal may aid in the management of invasive species, so we have developed microsatellite markers for this significant invader using an intersimple sequence repeat (ISSR)‐based cloning method. Eight polymorphic markers displayed between two and five alleles, with overall levels of observed and expected heterozygosities ranging from 0.0500 to 0.7500 and from 0.1449 to 0.7692, respectively.     

Methods of studying the distribution, diversity and abundance of birds in East Africa—some quantitative approaches

In this paper we compare the use of transect counts with a simpler method of investigating bird diversity and numbers, particularly in terrestrial habitats, both natural and non‐natural. Transect Counts (TCs) have long been widely used, whereas Timed Species Counts (TSCs), which estimate relative abundance, are comparatively untried. We find that TSCs give results which are comparable to those from TCs in most respects, except that they can only be used indirectly for estimating population densities, and they give different measures of diversity. However, TSCs generate data on many more species much faster than do TCs and are therefore more cost‐effective in most situations. In particular, TSCs are useful for community studies. We show, for example, that in natural habitats bird populations are positively correlated with the amount of woody vegetation, but not with rainfall. Diversity too increases with woody vegetation. Because TSCs are simple, more of them can be made for a given input of time, and hence more distributional data are obtained as an additional benefit.     

Genetic structure of Anogeissus dhofarica (Combretaceae) populations endemic to the monsoonal fog oases of the southern Arabian Peninsula

Anogeissus dhofarica (Combretaceae) is an endemic tree of the monsoon affected coastal mountains of the southern Arabian Peninsula, being the character species of the Hybantho durae–Anogeissetum dhofaricae association, a drought deciduous, monsoon forest community found only in the Dhofar region of southern Oman and the eastern Al‐Mahra region of south‐east Yemen. Due to the steep precipitation gradient from the centre to the edges in this monsoon affected area, A. dhofarica is found in two different habitat types: in continuous woodland belts of the Hawf and Dhofar mountains, and in isolated, scattered woodland patches, as found especially in the Fartak Mts (south‐east Yemen). Fifteen populations (212 individuals) from across the whole distribution area of the species were analysed using amplified fragment length polymorphism fingerprinting to: (1) evaluate the consequences of population fragmentation on the genetic diversity harboured in isolated patches versus cohering stands of the species and (2) to reconstruct the phylogeographical pattern of A. dhofarica as a consequence of oscillations in the monsoon activity during the Pleistocene and Holocene. The analysis of among‐population genetic differentiation and within‐population genetic diversity in A. dhofarica populations resulted in a lack of genetic pauperization and genetic differentiation of populations of the distinctly isolated patches of the Fartak Mts compared to the more luxurious forests of the Hawf and Dhofar regions. This is considered to be due to the high buffer capacity against the loss of genetic diversity caused by the long‐lived life‐form of the species combined with the capability to propagate clonally and the relatively recent fragmentation of Anogeissus forests into the described patches rather than due to high values of gene flow among remnant populations caused by bee pollination and anemochorical and hydrochorical diaspore dispersal. The phylogeographical pattern of the species argues for a quite recent fragmentation of a once continuous forest belt of A. dhofarica that is rather connected with climate changes in the Holocene than triggered by aridity–humidity oscillations reported for the Pleistocene. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97 , 40–51.     

A rapid serological test for detecting Fusarium oxysporum f.sp. narcissi in Narcissus

Polyclonal antiserum was elicited against a strain of Fusarium oxysporum f.sp. narcissi (GCRI80/26) and a specific and sensitive enzyme-linked immunosorbent assay developed. Antiserum raised to cell wall fractions gave better recognition than that to cytoplasmic fractions. Recognition was equally good in artificially and naturally infected bulbs. Little cross-reactivity in bulb tissue was shown by three other bulb-rotting fungi. Nine isolates of F. oxysporum f.sp. narcissi from a wide geographic area gave similar results in an indirect ELISA of mycelial extracts, although some cross-reactivity was observed with two other Fusarium spp. Four Fusarium spp. and four other fungi showed little cross-reactivity. Ten days after inoculation the pathogen was readily detected in the base plate area of three Narcissus cultivars and points remote from the inoculation site in the most susceptible cultivar. A direct correlation was observed between positive results in the enzyme-linked immunosorbent assay and recovery of the pathogen on selective medium.