<Emphasis Type="Italic">α</Emphasis>-Amylase inhibitor-1 gene from <Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> expressed in <Emphasis Type="Italic">Coffea arabica</Emphasis>plants inhibits α-amylases from the coffee berry borer pest

Background  

Coffee is an important crop and is crucial to the economy of many developing countries, generating around US70 billion per year. There are 115 species in the < i > Coffea < /i > genus, but only two, < i > C. arabica < /i > and < i > C. canephora < /i > , are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer ( < i > Hypotheneumus hampei < /i > ), is responsible for worldwide annual losses of around US70 billion per year. There are 115 species in the Coffea genus, but only two, C. arabica and C. canephora, are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer (Hypotheneumus hampei), is responsible for worldwide annual losses of around US500 million. The coffee berry borer exclusively damages the coffee berries, and it is mainly controlled by organochlorine insecticides that are both toxic and carcinogenic. Unfortunately, natural resistance in the genus Coffea to H. hampei has not been documented. To overcome these problems, biotechnological strategies can be used to introduce an α-amylase inhibitor gene (α-AI1), which confers resistance against the coffee berry borer insect-pest, into C. arabica plants.     

Effects of flow rate and temperature on cyclic gas exchange in tsetse flies (Diptera, Glossinidae)

Air flow rates may confound the investigation and classification of insect gas exchange patterns. Here we report the effects of flow rates (50, 100, 200, 400 ml min⁻¹) on gas exchange patterns in wild-caught Glossina morsitans morsitans from Zambia. At rest, G. m. morsitans generally showed continuous or cyclic gas exchange (CGE) but no evidence of discontinuous gas exchange (DGE). Flow rates had little influence on the ability to detect CGE in tsetse, at least in the present experimental setup and under these laboratory conditions. Importantly, faster flow rates resulted in similar gas exchange patterns to those identified at lower flower rates suggesting that G. m. morsitans did not show DGE which had been incorrectly identified as CGE at lower flow rates. While CGE cycle frequency was significantly different among the four flow rates (p < 0.05), the direction of effects was inconsistent. Indeed, inter-individual variation in CGE cycle frequency exceeded flow rate treatment variation. Using a laboratory colony of closely related, similar-sized G. morsitans centralis we subsequently investigated the effects of temperature, gender and feeding status on CGE pattern variation since these factors can influence insect metabolic rates. At 100 ml min⁻¹ CGE was typical of G. m. centralis at rest, although it was significantly more common in females than in males (57% vs. 43% of 14 individuals tested per gender). In either sex, temperature (20, 24, 28 and 32 °C) had little influence on the number of individuals showing CGE. However, increases in metabolic rate with temperature were modulated largely by increases in burst volume and cycle frequency. This is unusual among insects showing CGE or DGE patterns because increases in metabolic rate are usually modulated by increases in frequency, but either no change or a decline in burst volume.     

Morphometric measurement selection: an invertebrate case study based on weevils from sub-Antarctic Marion Island

A character-selection procedure initially applied in vertebrates (viverrid carnivores and murid rodents), but with a potential, more general application, was used to select appropriate characters for a morphometric investigation of weevils on Marion Island. An initial set of 23 linear measurements, adopted from a previous morphometric study, was subjected to cluster and ordination procedures to summarize patterns of correlations between measurements. Criteria were developed for the selection of representative measurements within cluster analysis-generated sub-clusters, after the exclusion of redundant measurements. This reduced the 23 initial variables to a final set of 15 measurements. The general grouping of variables was broadly consistent across all weevil species examined. Apart from economizing, by reducing the number of characters that have to be measured for subsequent analyses, the procedure also provides a way to adequately represent the phenotype, and to investigate morphological integration.     

Dynamic rearrangement of the filamentous actin network occurs during zoosporogenesis and encystment in the oomycete phytophthora cinnamomi

The organization of filamentous actin (F-actin) in living cells of the oomycete Phytophthora cinnamomi was determined during zoosporogenesis and zoospore encystment by microinjecting sporangia with fluorescently labeled phalloidin and observing resultant fluorescence by confocal microscopy. In multinucleate sporangia prior to the induction of cleavage, phalloidin labeling took the form of plaques which occurred mainly in the periphery of the sporangia. After induction of cleavage, phalloidin labeling showed that the plaques disappeared and that F-actin began to accumulate along the developing cleavage planes and around nuclei and water expulsion vacuoles. F-actin labeling was also observed near the plasma membrane in zoospores and young cysts but reverted to the plaque form in older cysts. Localization of F-actin close to the developing cleavage planes is consistent with the idea that actin microfilaments function in the positioning and expansion of the cleavage membranes. Observations of plaques of actin in living sporangia provide evidence that plaques are not aldehyde-induced fixation artifacts. Copyright 1998 Academic Press.     

Serglycin expression during monocytic differentiation of U937-1 cells

Serglycin is the major proteoglycan in most hematopoietic cells, including monocytes and macrophages. The monoblastic cell line U937-1 was used to study the expression of serglycin during proliferation and differentiation. In unstimulated proliferating U937-1 cells serglycin mRNA is nonconstitutively expressed. The level of serglycin mRNA was found to correlate with the synthesis of chondroitin sulfate proteoglycan (CSPG). The U937-1 cells were induced to differentiate into different types of macrophage-like cells by exposing the cells to PMA, RA, or VitD3. These inducers of differentiation affected the expression of serglycin mRNA in three different ways. The initial upregulation seen in the normally proliferating cells was not observed in PMA treated cells. In contrast, RA increased the initial upregulation, giving a reproducible six times increase in serglycin mRNA level from 4 to 24 h of incubation, compared to a four times increase in the control cells. VitD3 had no effect on the expression of serglycin mRNA. The incorporation of (35S)sulfate into CSPG decreased approximately 50% in all three differentiated cell types. Further, the (35S)CSPGs expressed were of larger size in PMA treated cells than controls, but smaller after RA treatment. This was due to the expression of CSPGs, with CS-chains of 25 and 5 kDa in PMA and RA treated cells, respectively, compared to 11 kDa in the controls. VitD3 had no significant effect on the size of CSPG produced. PMA treated cells secreted 75% of the (35S)PGs expressed, but the major portion was retained in cells treated with VitD3 or RA. The differences seen in serglycin mRNA levels, the macromolecular properties of serglycin and in the PG secretion patterns, suggest that serglycin may have different functions in different types of macrophages.      

Respiratory Metabolism of sub-Antarctic insects from different habitats on Marion Island

Oxygen uptake of the foliage-dwelling larvae ofEmbryonopsis halticella Eaton (Lepidoptera: Yponomeutidae) and adults ofEctemnorhinus marioni Jeannel (Coleoptera: Curculionidae), the litter-dwelling larvae ofPringleophaga marioni (Lepidoptera: Tineidae) and the wrack-dwellingParactora dreuxi Séguy (Diptera: Helcomyzidae) was examined over the range of temperatures experienced by these insects in their microhabitats. With the exception of the kelp fly,P. dreuxi, Q₁₀s and activation energies were generally lower than those found in temperate and Arctic insects, but were similar to values found in beetles from sub-Antarctic South Georgia Island. Q₁₀ and activation energy of each species reflected the temperature regime found in its microhabitat. Activation energies of the Marion Island species were intermediate between those found in temperate and polar arthropods, but towards the polar end of the range. The hypothesis that insects are capable of showing respiratory adaptation to temperature is supported.