mlo-based powdery mildew immunity: silver bullet or simply non-host resistance?

Durability and effectiveness against all genetic variants of a microbial species are hallmarks of so-called plant 'non-host' resistance. Highly effective immunity of monocotyledonous barley against the fungal powdery mildew pathogen, which is conferred by loss-of-function mutant alleles of the barley Mlo locus, likewise is a durable and broad-spectrum type of resistance. Although this was long considered as being a barley-specific phenomenon, recent findings indicate that mlo resistance can also occur in the distantly related dicotyledonous species Arabidopsis thaliana . Shared histological and phytopathological characteristics plus a conserved requirement for a set of genes in Arabidopsis mlo and non-host powdery mildew resistance indicate a potential common mechanism for these two seemingly distinct types of immunity.     

Physiological and Ecological Aspects of Gas Exchange by Sea Turtle Eggs

The sea turtle clutch of about 100 eggs is buried deeply inthe nesting beach.The eggs exchange respiratory gases with thesurrounding beach as their metabolic activity increases throughoutthe 60 day incubation. The O₂ consumption of individual eggsthroughout incubation is less than that of avian eggs of similarmass; however, this difference may be attributed to the differencein incubation temperature and growth rate. The O₂ consumptionof the sea turtle embryo is sufficiently low and the gas conductanceof the shell sufficiently large that only small gas partialpressure gradients occur across the shell. However, the metabolicintensity of the entire clutch is quite large, and since gasmovement through the beach is restricted, increasing gas partialpressure gradients are established between the center and peripheryof the clutch and between the clutch and surrounding beach.The rate of growth and mortality of the embryos is related torespiratory gas exchange, since maximum growth and hatchlingsuccess appear to occur in respiratory environments similarto those observed in natural nests. Embryonic growth slows andmortality increases in environments in which gas exchange isreduced below naturally occurring levels. Gas exchange considerationsmay influence nest construction, clutch size and incubationtime among sea turtles.     

Effect of C4 Depletion on the Utilization of the Terminal Components of Guinea-pig Complement by Endotoxin

ENDOTOXIN and antigen-antibody complexes (Ag-Ab) are potent inflammatory agents which induce marked pathophysiological effects in a number of animal species. Both these agents lead to increased vascular permeability, local accumulations of polymorphonuclear leucocytes and alterations in the coagulability of blood¹. There is mounting evidence that these similarities derive from endotoxins and Ag-Ab being activators of the complement (C) system, an important mediator of inflammation¹'². When endotoxins or preformed Ag-Ab are reacted with normal guinea-pig (GP) serum so as to induce equivalent consumption of whole haemolytic C, there are, however, striking differences in the consumption profiles of the individual C components³. Although interaction of Ag-Ab with GP serum results in the consumption of CI, C4 and C2 as well as C3 to C9, the interaction of endotoxin with GP serum leads to a marked depletion of C3 to C9 with little or no detectable loss of C1,C4 and C2 (ref. 3).     

Revision of the Neotropical genus Chimarrhodella Lestage (Trichoptera: Philopotamidae)

Abstract. A revision and phylogenetic analysis of the Neotropical genus Chimarrhodella Lestage is presented. Four described species are recognized, C.galeata (Martynov), C.peruviana (Ross), C.ulmeri (Ross) and C.nigra Flint. In addition, five new species are described, C.costaricensis sp.n. (Costa Rica), C.tapanti sp.n. (Costa Rica), C.flinti sp.n. (Venezuela), C.pilcopata , sp.n. (Peru) and C.tobagoensis sp.n. (Tobago). These species are organized into two monophyletic species groups, designated here the Galeata Group and the Peruviana Group. The Galeata Group is characterized by having male genitalia with tergum X possessing well developed lateral lobes bearing sclerotized, spine-like processes and includes C.galeata, C.costaricensis, C.flinti, C.pilcopata and C.tapanti. The Peruviana Group is characterized by having male genitalia with tergum X only slightly divided apically, tergum IX bearing hook-like processes posteriorly, and female genitalia with segment VIII much elongated in comparison to the Galeata Group and includes C.peruviana, C.nigra, C.tobagoensis and C.ulmeri. Records of the genus from Costa Rica and Tobago represent significant extensions of the known range for the genus, previously unknown north of Panama. A key to males and known females and a species-level phylogenetic analysis are included.     

Replication of Nosema Algerae In Three Insect Cell Lines

SYNOPSIS Nosema algerae , a microsporidan parasite of anopheline mosquitoes, was successfully replicated in 3 insect cell culture lines: Trichoplusia ni (TN-368); Heliothis zea (IPLB-1075); and Mamestra brassicae (IZD-Mb-0503). Infectious spores were produced in vitro. Spores were observed at 48 h postinfection, and some cells were filled with sproes by 72 h.
The number of parasites per cell increased with time. At 72 h postinfection, the infection rates for the 3 cell lines ranged from 23 to 32%. Infected cell lines were subcultured, and by the 6th passage spore production had ceased.     

Avian biodiversity monitoring in Australian rangelands

Abstract Birds have been widely regarded as a key element in monitoring biodiversity both in Australia and elsewhere. We believe that, although birds are unlikely to be an umbrella or indicator taxon for other biota (other vertebrates, invertebrates, plants, microorganisms), they do represent a taxon that can be monitored more easily and with less effort per datum than other biotic components. It has been shown by the great participation rate of lay observers (whom we call monitors) in several schemes (notably the Birds Australia Atlas programs) that there is a capacity to mobilize the public to undertake bird surveying. Although there are many limitations to acquiring high‐quality information (scale, dynamism, mobility, irruptiveness, paucity of monitors over much of the rangelands), we think that these can be dealt with to allow the use of birds as a key component of biodiversity monitoring. We outline some of the possible options for statistically characterizing monitoring data for rangeland birds.