Salmonellae in the African great cane rat (Thryonomys swinderianus)

Because of its large size, the African great cane rat (Thryonomys swinderianus) is valued for food and has become a popular meat in western Africa. A survey was conducted to determine the occurrence of salmonellae in cane rats. Ten strains of Salmonella sp. were isolated from eight of 25 (32%) cane rats. Salmonella ajiobo was isolated from the spleen and intestines of three cane rats; S. agama was obtained from the spleen, liver and intestines of three animals; and S. poona was isolated from the spleen and liver of two cane rats. The occurrence of salmonellae in T. swinderianus is a potential public health hazard. Humans may become exposed to infection by consumption of inadequately cooked infected cane rat meat, or by eating vegetables, sugar cane and fruits contaminated with excretions of carrier cane rats. Incidents of human salmonellosis attributable to cane rat meat have not yet been reported; however, all three serotypes isolated from the cane rats have also been isolated from stools of patients suffering from gastroenteritis in Nigeria.     

Population studies ofCavelerius saccharivorus Okajima (Heteroptera: Lygaeidae): A few findings on population interchange

The change in population density of Cavelerius saccharivorus was studied in the sugar cane field and the Miscanthus habitats around it. This species spent 2 (or partly 3) generations a year. It was suggested that the density rose in the sugar cane field where the density had been low enough, when the population density increased in the nearby sugar cane fields. Likely, the density in the Miscanthus habitat increased with the density in the nearby sugar cane field. It seems that these are mainly due to flying movement of adults, and that the movement takes place in every season. It was found through the investigation in the sugar cane field that the percentage of long-winged adults increased with the population density. These adults seemed to emmigrate to the nearby sugar cane fields and Miscanthus habitats. The remarkable increase in the percentage of long-winged adults in the sugar cane field was probably due to the immigration into there. In the Miscanthus habitat the adult population was consisted mainly of long-winged ones. Through all the observations, it was suggested that the adult movement was associated with the population regulation and performed chiefly by long-winged adults.     

Nitrogen-fixing bacteria of the genusBeijerinckia Derx in the rhizosphere of sugar cane

Summary and Conclusions The rhizosphere effect of sugar cane on nitrogen fixing bacteria of the genusBeijerinckia Derx was studied under field conditions, during two growing periods of the cane. Counts ofBeijerinckia in soil samples from the rhizosphere and from the rhizoplan (soil from root surface) showed an increase in this nitrogen fixer of up to 20 times in the rhizosphere and up to 50 times in the rhizoplan. Bacteria, actinomyces, and fungi developing on egg-albumin agar decreased in the rhizosphere of sugar cane.This work was in part, supported by the Conselho Nacional de pesquisas.     

Use of a cane for recovery from backward balance loss during treadmill walking

Purpose. To study whether a cane improved balance recovery after perturbation during walking.

Method. This study was a crossover comparison comparing the effect of walking with and without a cane for balance recovery after perturbation during treadmill walking. Five normal young volunteers participated. The velocity and acceleration of a marker sited on the seventh cerebral vertebra (C7) and vertical hand motion were measured by a motion analysis system.

Result. When using a cane, C7 backward velocity increased by approximately 15% (413 SD 95?mm/s with cane vs. 358 SD 88?mm/s without). In addition, C7 backward acceleration increased by approximately 23% (3.2 SD 0.7?m/s² with cane vs. 2.6 SD 0.8?m/s² without) and the vertical motion of the right hand decreased (187 SD 98?mm with cane vs. 372 SD 260?mm without). Additionally, no subject was able to use a cane to broaden their base of support.

Conclusions. The ability to limit trunk extension is crucial for preventing falls. Therefore, using a cane jeopardizes recovery from backward balance loss. The results encourage further research on the risk of a cane on balance recovery for the elderly population and habitual cane users.     

Influence of the burning of sugar cane prior to its harvesting upon the production of single-cell protein from bagasse pith

Summary A culture of Cellulomonas sp. and Bacillus subtilis was grown using sugar cane bagasse pith from unburnt sugar cane (UCP) as the source of carbohydrates. The yield and production values were proved to be higher than those obtained with burnt sugar cane (BCP).For UCP the maximum protein production was 7.8 g/l, the cellulolytic activity being 70 %, with a protein/hydrolyzed pith yield of 22 %. For BCP, the maximum protein value was 4.6 g/l, with a cellulolytic activity of 55 % and a protein/hydrolyzed pith of 17 %.The possibility of a chemical inhibitor being present in BCP is discarded because of the alkaline pretreatment and the results obtained on treating the pith from burnt cane with a benzene-ethanol (2:1) mixture. These results were the same as the ones obtained without the benzene-ethyl alcohol mixture extraction.     

Competing tadpoles: Australian native frogs affect invasive cane toads (Rhinella marina) in natural waterbodies

The cane toad (Rhinella marina) is one of the most successful invasive species worldwide, and has caused significant negative impacts on Australian fauna. Experimental work in the laboratory and in mesocosms has shown that tadpoles of native frogs can affect survival, size at metamorphosis and duration of larval period of cane toad tadpoles. To test if these effects occur in nature, we conducted a field experiment using two temporary ponds where we set up enclosures with tadpoles of native green tree frogs (Litoria caerulea) and cane toads in treatments with a range of densities and combinations. The presence of green tree frog tadpoles significantly decreased the growth rate of toad tadpoles and increased the duration of their larval period in both ponds; in one pond, frog tadpoles also significantly reduced the body length and mass of metamorph toads. Toad tadpoles did not have any significant negative effects on green tree frog tadpoles, but there was strong intraspecific competition within the latter species: increased frog tadpole density resulted in increased larval period and reduced survival, growth rate and size at metamorphosis for frogs at one or both ponds. Our results are encouraging for the possibility of using native frogs as one component of an integrated approach to the biological control of cane toads.     

Effects of an invasive species on refuge‐site selection by native fauna: The impact of cane toads on native frogs in the Australian tropics

Invasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge‐site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet‐dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non‐random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat‐site availability for native frogs.     

The biology and life history of currant clearwing,Synanthedon tipuliformis (Lepidoptera: Sesiidae), in Canterbury

Abstract

Details of the life cycle and biology of currant clearwing, Synanthedon tipuliformis (Clerck), in Canterbury, New Zealand, are discussed. The adults live for about 7 days, and are found from mid November to early January. The sex ratio approximates 1:1. Adults are active only when the air temperature exceeds 15°c, and peak flight activity is observed on cloudy days at 20-23°c. Males are attracted to females between 1400 h and 1600 h, and mating lasts for over 2 h. Fecundity averaged about 100 eggs per female, and fertility exceeded 98%. Egg incubation required an average of 19 days in the field; the thermal constant is 91 day degrees. The mean number of eggs per blackcurrant cane varied in different years from 2.68 to 13.54; there was no significant difference between blackcurrant varieties in the same year. Larvae entered the cane through openings or axillary buds and then fed on the pith until late April or May. Quiescence occurred during winter, and feeding resumed in late August or September. Larvae tunnelled 15.20 ± 0.74 cm of pith. It is suggested that there are six larval instars. Mean numbers of larvae per cane varied in the early stage from 1.91 to 7.36, and at the post-winter stage from 1.23 to 3.10. Pupation occurred in mid October, and the pupal stage lasted for up to 6 weeks; the thermal constant is 216 day degrees. Mortality factors discussed include establishment failure, parasites, pathogens, predators, larval combat, winter pruning, loss of pupae at cane breaks, and pupal eclosion failure. The first record of the fungus Cordyceps sp. attacking currant clearwing is reported.     

Muscle weights and succinic dehydrogenase distribution in the hind limb musculature of two rodents (Thryonomys gregorianus and Pedetes capensis) with different locomotory habits

The hind limb muscles of the spring hare (Pedetes capensis) were found to be relatively heavier than the hind limb muscles of the cane rat (Thryonomys gregorianus). The distribution of succine dehydrogenase activity was investigated in four of these muscles (m. gluteus superficialis, m.semimembranosus, m. biceps femoris and m.rectus femoris) from both animals. It was found that the spring hare had a higher proportion of low-activity fibres in all four muscles than the cane rat. All muscle fibre types were also smaller in diameter in the spring hare than the cane rat. These results are discussed in relation to the different locomotry habits of the two animals.     

Cinétique de dégradation des hydrocarbures par Candida lipolytica

Résumé Le mécanisme d'assimilation des hydrocarbures par une levure, Candida lipolytica est étudié au moyen de l'analyse cinétique de la croissance du microorganisme et de la disparition du substrat hydrocarboné. Les hydrocarbures utilisés sont des n-paraffines. On ajoute au milieu soit un seul hydrocarbure (n-tetradécane ou n-hexadécane), soit un mélange binaire (n-dodécane et n-heptadécane), soit un mélange complexe (du n-undécane au n-octadécane). Contrairement à d'autres auteurs, nous pensons qu'il est peu probable que l'essentiel de la réaction s'effectue par contact des gouttes de substrat et des microorganismes puisque l'on observe des retards d'assimilation de certains hydrocarbures: ceux de faible poids moléculaire (les plus solubles) sont assimilés plus rapidement. Il semble donc que l'assimilation se fasse en grande partie à partir d'hydrocarbures préablement solubilisés.

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Kinetics of hydrocarbon assimilation by Candida lipolytica

Summary The mechanism of hydrocarbon uptake by a yeast, Candida lipolytica has been studied by means of the kinetic analysis of micro-organism growth and substrate assimilation. Hydrocarbons used as only source of carbon are normal alkanes either pure (n-tetradecane or n-hexadecane) or in mixture of two paraffins (n-dodecane and n-heptadecane) or eight paraffins (n-undecane to n-octadecane). In these last cases delays in n-alkanes consumption are observed. They show that the most soluble substrates (lower molecular weight) are first consumed. In opposition to other authors we think that there is little probability for main reaction occurring by direct contact between drops and micro-organisms. The evidence indicates that n-alkanes are mainly utilized in the dissolved state.

     

Alkali‐based AFEX pretreatment for the conversion of sugarcane bagasse and cane leaf residues to ethanol

Sugarcane is one of the major agricultural crops cultivated in tropical climate regions of the world. Each tonne of raw cane production is associated with the generation of 130 kg dry weight of bagasse after juice extraction and 250 kg dry weight of cane leaf residue postharvest. The annual world production of sugarcane is ～1.6 billion tones, generating 279 MMT tones of biomass residues (bagasse and cane leaf matter) that would be available for cellulosic ethanol production. Here, we investigated the production of cellulosic ethanol from sugar cane bagasse and sugar cane leaf residue using an alkaline pretreatment: ammonia fiber expansion (AFEX). The AFEX pretreatment improved the accessibility of cellulose and hemicelluloses to enzymes during hydrolysis by breaking down the ester linkages and other lignin carbohydrate complex (LCC) bonds and the sugar produced by this process is found to be highly fermentable. The maximum glucan conversion of AFEX pretreated bagasse and cane leaf residue by cellulases was ～85%. Supplementation with hemicellulases during enzymatic hydrolysis improved the xylan conversion up to 95–98%. Xylanase supplementation also contributed to a marginal improvement in the glucan conversion. AFEX‐treated cane leaf residue was found to have a greater enzymatic digestibility compared to AFEX‐treated bagasse. Co‐fermentation of glucose and xylose, produced from high solid loading (6% glucan) hydrolysis of AFEX‐treated bagasse and cane leaf residue, using the recombinant Saccharomyces cerevisiae (424A LNH‐ST) produced 34–36 g/L of ethanol with 92% theoretical yield. These results demonstrate that AFEX pretreatment is a viable process for conversion of bagasse and cane leaf residue into cellulosic ethanol. Biotechnol. Bioeng. 2010;107: 441–450. © 2010 Wiley Periodicals, Inc.     

The effect of sprays of thiophanate–methyl on cane diseases and yield in red raspberry, with particular reference to cane blight (Leptosphaeria coniothyrium)

Spur blight (Didymella applanata), cane botrytis (Botrytis cinerea) and cane blight (Leptosphaeria coniothyrium) were studied in two consecutive seasons in unsprayed raspberries and in plots sprayed with thiophanate-methyl in the first season alone, (a) twice pre-harvest, (b) twice post-harvest, or (c) twice pre- plus twice post-harvest. Pre-harvest, but not post-harvest sprays, gave moderate control of both spur blight and cane botrytis; both diseases occurred mainly on the lower halves of canes, the latter being the less common. Cane blight occurred at the base of canes where they were wounded by old cane stubs. In the first year it was severe; 37% of canes died before harvest in the unsprayed plots. The three spray programmes all decreased cane death due to cane blight and they all increased yield by c. 45% even in those plots sprayed post-harvest where spur blight was severe and not controlled. Clearly this last disease, despite its high incidence, had no effect on potential yield in this experiment. In the second year cane blight was common but less severe and the incidence of its lesions was reduced similarly by all programmes, but only 4% of canes died in control plots. Analysis of the potential yield and the sizes of lesions caused by L. coniothyrium in canes inoculated at fortnightly intervals in the previous year showed that potential yield loss occurred only when lesions girdled canes. A bimodal distribution in the lesion sizes, measured by length or girdling, indicated some endogenous control of lesion development which might explain the marked differences in the effect of cane blight on potential yield in two seasons.     

Nitrogenase activity in the rhizosphere of sugar cane and some other tropical grasses

Summary Roots of sugar cane had considerable nitrogenase activity and produced up to 5 n moles ethylene/h/g root by the reduction of acetylene. The rhizosphere soil and soil mid-way between the cane rows also reduced acetylene.Beijerinckia indica was abundant on roots and in the soil. Nitrogenase activity was also associated with roots ofPanicum maximum,Pennisetum purpureum andCymbopogon citratus.     

Interaction of <Emphasis Type="Italic">Azospirillum brasilense</Emphasis> and <Emphasis Type="Italic">Glomus intrarradix</Emphasis> in Sugar Cane Roots

Fifteen-day-old variety NA 56-79 sugar cane seedlings were inoculated with Azospirillum brasilense and Glomus intrarradix. This article aims at examining changes in sugar cane root seedlings inoculated with Glomus intrarradix and Azospirillum brasilense, the increase in microbial biomass and the acetylene reduction process as well. The internal root colonization was studied 20 days after inoculation using scanning and a transmission electron microscope. Both microorganisms entered the sugar cane root through the emergent lateral roots. The microorganisms were capable of coexisting both intra and intercellularly, producing changes in the cell wall, thus allowing colonization and interaction between the organisms. These changes increased the number of microorganisms inside the root as well as acetylene nitrogen reduction. Sugar cane plant biomass increased with joint-inoculation. The number of endophytic microorganisms and nitrogen fixing activity increased when they were colonized by Azospirillum and Glomus together.     

Improved methodology for isolation of Acetobacter diazotrophicus and confirmation of its endophytic habitat

Nitrogen-free, semi-solid defined medium with crystallized cane sugar (100 g/l) supplemented with cane juice (5 ml/l) was the most selective for isolating Acetobacter diazotrophicus. Surveys of A. diazotrophicus using this medium showed that >10³ cells/g fresh wt were present at all sites in all parts of the sugar cane plant and in all trash samples examined, reaching up to 10⁷/g. Additional samples, from forage grasses and cereals and from weed species collected within the sugar cane fields, were all negative. Heat treatment (50°C for 30 min) of the sugar cane setts did not affect A. diazotrophicus numbers within the plant. Nitrogenase activity of intact soil-plant systems in pots planted with heat-treated setts did not respond to inoculation with A. diazotrophicus. The endophytic habitat of this diazotroph and its propagation within the stem cuttings was confirmed.The authors are with EMBRAPA-CNPAB, Cx Postal 74.505, Seropédica, Rio de Janeiro, 23851-970, Brazil     

Malocclusion in an African rodent. Is it necessarily fatal?

The greater cane rat, Thryonomys swinderianus , is the second largest rodent in the southern African subregion; only the porcupine is larger. The incisors are very large and curved and their gnawing action against each other gives them chisel edges. The common belief that a broken incisor may lead to severe stress or even death because growth of the corresponding incisor, in the opposing jaw, cannot be controlled by wearing away, is not necessarily true for all rodents. At least in the greater cane rat malocclusion does not necessarily lead to the incisors entering the skull or any obvious signs of stress or suffering.     

Bioconversion of phytosterols to androstanes by mycobacteria growing on sugar cane mud

Direct sterol conversion of sugar cane mud (residue) by Mycobacterium sp. was demonstrated to be possible technologically, thus avoiding sugar cane oil extraction and further processes of extraction and purification of phytosterols from this oil. Indeed, mycobacterial cells were able to convert phytosterols from sugar cane mud into 4-androstene-dione (AD) and 1,4 androsta-diene-3,17-dione (ADD). For the various concentrations assayed, concomitant higher yields for both androstanes were achieved at 20% (w/w) sugar cane mud in media. Furthermore, conversions were similar to those from other substrates, such as a mixture of phytosterols. The results suggest that the mycobacterial cell is able to easily access and bioconvert sugar cane mud phytosterols.     

Evaluating Tolerance of Herbicide and Transplantation by Cane (a Native Bamboo) for Canebrake Restoration

Canebrakes (bamboo grasslands dominated by Arundinaria spp.) were once a widespread ecosystem across the Southeastern United States, and many species of wildlife depended upon them. Early settlers replaced this system with subsistence agriculture and today few canebrakes remain. The restoration of canebrakes is critical to the recovery of several wildlife species; however, restoration is complicated because (1) seed is uncommon and often predated, (2) competition from hardwood species, including the exotic Chinese privet (Ligustrum sinesnse), often prevent cane establishment, and (3) cane depends on disturbance regimes that have been disrupted in the Southeast. We investigated the tolerance of Switch cane (Arundinaria tecta) to four commonly used herbicides that are effective at controlling privet and other hardwoods: hexazinone (Velpar‐L), glyphosate (Razor Pro), triclopyr (Garlon 3A), and imazapyr (Chopper). We also investigated the possibility of transplanting cane culms, and the factors affecting successful transplant. Cane tolerated hexazinone and triclopyr but was damaged or killed by glyphosate and imazapyr. Although many measures of weather and cane condition were not predictors of transplant success, the Keetch–Byram drought index was a strong predictor, and is available through most state forestry offices. Selective herbicides and deliberately timed transplantation may be important canebrake restoration tools.     

Vigour control, an integrated approach to cane, pest and disease management in red raspberry (Rubus idaeus)

The first flush of young canes of red raspberry (Rubus idaeus) was removed at different dates in spring, using the contact herbicide dinoseb. In comparison with untreated plots, cane removal increased fruit yield, controlled excessive cane vigour, and improved the health status of vegetative canes in a plantation infested by raspberry cane midge (Resseliella theobaldi). At the end of the growing season vegetative canes on treated plots were shorter and thinner, and sustained less physical injury than those on untreated plots. Access to the fruit at harvest was also improved. Reduced competition between fruiting and vegetative canes increased yield in the year of treatment by an average of 35%. Yield was not affected by date of cane removal, but growth of replacement cane was reduced below optimum when first flush cane was removed after mid-May. The later the canes were removed, the less was the incidence of pest and diseases. Cankers and lobate vascular lesions (‘patches’) resulting, respectively, from the feeding of first and second generation midge larvae (with associated fungi) affected fewer canes in treated than in untreated plots. Significantly fewer live larvae of R. theobaldi were recovered in the following winter from soil in plots treated on or after 11 May than from untreated plots. The main effect of vigour control on R. theobaldi and midge blight was that replacement canes provided fewer egg-laying sites (natural splits) than did the first flush canes on untreated plots. The incidence of spreading vascular lesions (‘stripes’) attributed to Leptosphaeria coniothyrium infecting either physical wounds (cane blight) or midge feeding wounds (midge blight) was substantially less in treated than untreated plots. Cane botrytis (Botrytis cinerea) and spur blight (Didymella applanata) were also less common in treated plots. Interactions between vigour control and pest and disease incidence are discussed in relation to the efficient management of cv. Glen Clova in eastern Scotland.