Quantitation of malaria sporozoites transmitted in vitro during salivation by wild Afrotropical Anopheles

Abstract. The malaria transmission potential of wild, infective Anopheles from western Kenya was evaluated by determining the number of sporozoites transmitted in vitro by salivation when their mouthparts were inserted into capillary tubes containing either sucrose or blood. With sucrose, 86.6% of 102 infective Anopheles transmitted a geometric mean (GM) of 3.84 sporozoites (range 1–34). With blood, 23.1% of 104 infective Anopheles , tested on the day of collection, transmitted a GM of 2.30 sporozoites (range 1–117). For Anopheles held 5 days postcapture before testing with blood, 53.6% of 56 transmitted a GM of 6.04 sporozoites (range 1–420). Transmitting Anopheles contained significantly more salivary gland sporozoites than non-transmitters. No significant differences were detected between Anopheles gambiae Giles sensu lato and Anopheles funestus Giles in sporozoite transmission by individuals with sporozoites in their salivary glands.
Sporozoites were detected microscopically in the salivary duct from heads in 80.3% of 117 infective Anopheles (GM=11.2, range 1–71). Sporozoite detection in mosquito heads by ELISA was 25% less efficient than microscopic detection.
Over 98% of the infective Anopheles transmitted less than twenty-five sporozoites. Transmitted sporozoites represented only about 3% of the total sporozoites in the salivary glands suggesting that sporozoite transmission may be restricted to sporozoites in the salivary duct at the time of feeding. Results are discussed in relation to anti-sporozoite vaccine development.     

On Arborescence in Gahnia clarkei and Gahnia sieberiana

Specimens of Gahnia sieberiana from Brisbane, Queensland, andof Gahnia clarkei from near Orbost, Victoria, were collectedand examined both morphologically and anatomically. The speciesgrow in wet areas and are of interest because they representthe largest arborescent species known in the Cyperaceae. Stemdiameters up to 120 mm and stems up to 10 m long have been observed.Such long stems tend to be supported by nearby vegetation. Althoughfresh stems are tough and woody, they are brittle. Branchingof the stems is sympodial, and numerous branches are producedby plants growing in exposed habitats. There is less branchingin plants from shaded habitats. Basal shoots may also occur.Adventitious roots develop basally on most plants, but withG. sieberiana, some adventitious roots form near the shoot apexand grow in and around leaf bases. Anatomical features of interestare an endodermoid layer composed of sclereids with elongate,undulated, outer tangential walls that are lignified and suberized,short vessel elements with horizontal to oblique simple perforationplates, and relatively short sclereids surrounding vessel elementsin the vascular bundles. Some vascular bundles are bipolar.The presence of short vessel elements here is in marked contrastto the longer tracheary elements in other arborescent monocotyledons. Arborescence, stem anatomy, Cyperaceae, Gahnia, saw sedge, Monocotyledon, bipolar bundles, morphology, endodermoid layer     

Leaf age and larval performance of the leaf beetle Paropsis atomaria

ABSTRACT.

• 1 Larval performance of the leaf beetle Paropsis atomaria Oliver was determined for larvae raised on both new and mature leaves of Eucalyptus blakelyi Maiden. Larvae were transferred to mature leaves at different ages; control larvae stayed on new leaves through all instars.
• 2 Only larvae reared on new leaves through the third instar survived to pupate on mature leaves; developmental time was prolonged by 20% and pupal weight was reduced by 50% in these larvae compared with larvae reared entirely on new leaves. Almost all larvae died when transferred to mature leaves as first, second or third instars.
• 3 Low survival and slow development on mature leaves was mainly due to failure by larvae to feed. Larvae palpated leaves and could discriminate among leaf ages immediately, without biting into the leaf tissue.
• 4 New leaves had higher concentrations of oil and tannins than old leaves, while there were no significant differences in nitrogen concentrations in the two types of leaves. Mature leaves were more than 3 times tougher than new leaves, in terms of g mm^?2 of penetrometer force.
• 5 In drought years E. blakelyi may not produce sufficient new leaves to supply specialist herbivores with their preferred food resource. We infer that drought years reduce P. atomaria larval performance significantly, and influence the population dynamics of the insect.

     

Chemical treatments for control of decay in pruning wounds

Wound treatments were evaluated, in the laboratory and the field, for their effect on beech and poplar tissue (phytotoxicity) and on the growth and colonisation pattern of micro-organisms. Three types of treatment were examined: a physical barrier or sealant, a sealant plus fungicide and a fungicide alone. Greatest phytotoxicity was shown by materials normally employed as timber preservatives and the least by sealants. Generally colonisation by fungi and bacteria was little delayed by most treatments with the exceptions of Santar (sealant plus mercuric oxide) and Australian Arborseal (sealant plus captafol). However, colonisation by basidiomycetes was generally delayed by treatment, but its overall intensity was reduced only by Santar and Lac Balsam (sealant). Some treatments had a selective effect on the species of micro-organisms colonising a wound - thus wounds treated with carbendazim derivatives were most likely to be colonised by basidiomycetes and Alternaria spp. Treatment with Santar discouraged most micro-organisms with the exception of Phoma spp. No sealant provided a visually intact cover for longer than 12 months: even wounds with apparently intact cover occasionally had fruit bodies of decay fungi present on them. The chemicals triadimenol, triadimefon, carbendazim and thiophanate methyl were still present in fungicidal amounts in wounds up to at least 157 days. Both Santar and triadimenol prevented the growth of Trametes versicolor from inoculum plugs in wounds of apple trees.     

Anthocyanin composition of and distribution in the Poaceae (Gramineae)

Delphinidin 3, 5-diglueoside was identified in Nardus stricta and peonidin 3-arabinoside in Plialaris arundinaeea. Cyanidin 3-glucoside was found in all of 21 other grasses examined; it was accompanied by the 3-arabinoside in seven species. It is concluded that anthocyanin pigmentation has no general taxonomic importance in the family but that this is the result to be expected in a wind-pollinated plant group.     

Amyloplast Sedimentation in Shoot Statocytes having a Large, Central Vacuole: Further Interpretation from Electron Microscopy

The claim (Lawton, Juniper, and Hawes, 1986) that amyloplastssediment through the central vacuole of geostimulated shootstatocytes has been critically examined. As the result of ourTEM study of Taraxacum statocytes and from theoretical considerationsof amyloplast sedimentation, we conclude that it is possiblefor individual amyloplasts surrounded by a layer of tonoplast-boundedcytoplasm to travel occasionally through the vacuole, but unlikelythat the majority of the amyloplasts in a statocyte sedimentin this manner. We put forward a scheme for amyloplast movementin shoot statocytes which emphasizes the fluidity of the tonoplastmembrane. In this scheme, it is expected that most amyloplastssediment in peripheral cytoplasm down the statocyte cell wall,but amyloplasts may also, as they sediment, create or breaktransvacuolar strands, or move through already existing transvacuolarstrands, or fall through the vacuole while enclosed by somecytoplasm and tonoplast membrane. Finally, it is suggested thatthe tonoplast membrane may have been neglected as a membranesite for detection of the gravity stimulus through interactionwith sedimenting amyloplasts. Key words: Amyloplast sedimentation, statocytes, geotropism, Taraxacum officinale     

The Effects of Elevated Atmospheric Carbon Dioxide and Water Stress on Ligth Interception, Dry Matter Production and Yield in Stands of Groundnut (Arachis hypogaea L.

Stands of groundnut (Arachis hypogaea L.), a C₃ legume, weregrown in controlled-environment glasshouses at 28 °C (±5°C)under two levels of atmospheric CO₂ (350 ppmv or 700 ppmv) andtwo levels of soil moisture (irrigated weekly or no water from35 d after sowing). Elevated CO₂ increased the maximum rate of net photosynthesisby up to 40%, with an increase in conversion coefficient forintercepted radiation of 30% (from 1–66 to 2–16g MJ^–1) in well-irrigated conditions, and 94% (from 0–64to 1·24 g MJ^–1) on a drying soil profile. In plantswell supplied with water, elevated CO₂ increased dry matteraccumulation by 16% (from 13·79 to 16·03 t ^–1) and pod yield by 25% (from 2·7 to 3·4t ha^–1).However, the harvest index (total poddry weight/above-grounddry weight) was unaffected by CO₂ treatment. The beneficial effects of elevated CO₂ were enhanced under severewater stress, dry matter production increased by 112% (from4·13 to 8·87 t ha^–1) and a pod yield of1·34t ha^–1 was obtained in elevated CO₂, whereascomparable plotsat 350 ppmv CO₂ only yielded 0·22 t ha^-1.There was a corresponding decrease in harvest index from 0·15to 0·05. Following the withholding of irrigation, plants growing on astored soil water profile in elevated CO₂ could maintain significantlyless negative leaf water potentials (P<0·01) for theremainder of the season than comparable plants grown in ambientCO₂, allowing prolonged plant activity during drought. In plants which were well supplied with water, allocation ofdry matter between leaves, stems, roots, and pods was similarin both CO₂ treatments. On a drying soil profile, allocationin plants grown in 350 ppmv CO₂ changed in favour of root developmentfar earlier in the season than plants grown at 700 ppmv CO₂,indicating that severe waterstress was reached earlier at 350ppmv CO₂. The primary effects of elevated CO₂ on growth and yield of groundnutstands weremediated by an increase in the conversion coefficientfor intercepted radiation and the prolonged maintenance of higherleaf water potentials during increasing drought stress. Key words: Arachis hypogaea, elevated CO₂, water stress, dry matter production     

Callionymus russelli, a new species of callionymid fish from Queensland, Australia

A new species of dragonet, Callionymus russelli, is described from Queensland waters. Callionymus russelli may be distinguished from the closely related species, C. punctatus, by the colour patterns of the first dorsal fins, by the smaller size, by the snout length being the same or slightly less than the eye length, by the preopercular spine being slightly longer than the eye, and by the caudal fin length in the female being only slightly longer than the head, and rarely twice the length of the head in the male. From the other Queensland species of Callionymus, its small size will eliminate it from being confused with the majority of species. It differs from C. calliste and C. macdonaldi, the only two of similar size, by having a somewhat pointed snout, different dorsal fin colour patterns, and the distinct body markings of numerous light or dark brown vertical streaks along the sides of the body in males. A revised key to the Australian dragonet species within the genus Callionymus is given.     

Seed Maturation in Soybeans (Glycine max L. Merr.) is Independent of Seed Mass and of the Parent Plant, Yet is Necessary for Production of Viable Seeds

Freshly harvested seeds of soybean (Glycine max L. Merr.) orseeds shelled, then dried, were non-viable. Seeds dried in intactpods, even when only 17% of normal size, matured into viableseeds and produced healthy plants. These seeds maintained activityof various enzymes but gained little soluble protein while air-dryingin intact pods. There was a qualitative change in seed proteinsassociated with maturation. Seeds matured in intact pods havea greater proportion of protein as slow-moving bands and havecompletely lost one fast-moving band compared with seeds shelledbefore drying. Seed maturation is a distinct phase of seed production,is independent of the parent plant, and can be imposed on theseed at many stages of development.