Long-term exposure of Boeckellagibbosa (Copepoda, Calanoida) to in situ levels of solar UVB radiation

1. The freshwater calanoid copepod Boeckella gibbosa is typical of high elevation lakes and ponds in Patagonia (Argentina). Previous studies have shown that this species is highly tolerant to short-term exposure to natural and artificial UVB radiation, and that its tolerance is due to photoreactivation by longer wavelength radiation. In this study, we investigate the potential sublethal effects of solar radiation after prolonged exposure.
2. We incubated B. gibbosa at 1 m depth in oligotrophic Lake Toncek for 24 days. The incubation chambers were 1.2 l acrylic cylinders covered with appropriate filters in order to obtain three radiation treatments: visible radiation only, visible radiation + UVA and visible radiation + UVA + UVB.
3. The three treatments did not differ significantly in variables considered as indicators of survival (number of individuals), reproduction (proportion of ovigerous females, clutch size) and development (instar composition). Although resistance to solar UVB radiation is certainly a requisite to live in transparent high elevation habitats, the fact of being effectively exposed to natural levels of UVB radiation does not seem to have measurable consequences on an already adapted species, such as B. gibbosa     

Inhibition of Early Endosome Fusion by Trypansom cruzi-Infected Macrophage Cytosol

ABSTRACT. Trypanosoma cruzi trypomastigotes survive inside macrophages by promoting fusion between the parasitophorous vacuole and mature host lysosomes upon internalization. Since trypomastigotes can evade the lytic pathway, the earliest steps of endocytosis, such as early endosome fusion, may be affected. To test this hypothesis, we used an in vitro early endosome fusion assay. Our results show that trypomastigote-infected macrophage cytosols cannot promote fusion between early endosomes, compared to mock-infected cytosols (heat-killed trypomastigotes were used in the parasite-macrophage interaction assay). GTPγS addition potentiates the fusogenic activity driven by trypomastigote-infected macrophage cytosol-mediated assays, unlike the biphasic fusogenic effect obtained with GTPγS treatment of macrophage cytosol controls. Calcium-stimulated early endosome fusogenic processes are not affected in the assays mediated by infected macrophage cytosol. We conclude that GTP-regulated factors, and not calcium-regulated elements, are involved in the inhibition of the early endosome fusogenic process by the trypomastigote-infected macrophage cytosol. This primary impediment to the progress of a normal endocytosis may be a relevant step required for the lysosomal recruitment-fusion of the host lysosmes upon trypomastigote infection and further survival of the parasite within its host.     

Identification and characterization of a new group of root-colonizing fungi within the Gaeumannomyces–Phialophora complex

A new group of darkly pigmented root-infecting fungi was isolated from cereal roots obtained from six different locations in northeastern Germany. Similar random amplified polymorphic DNA(RAPD) patterns and restriction profiles of amplified rDNA were used as a basis for classifying the isolates in a separate group. The isolates demonstrating mycelial and infection characteristics typical of Gaeumannomyces graminis could be differentiated from the varieties of G. graminis as well as from Gaeumannomyces cylindrosporus / Phialophora graminicola using RAPD Polymerase chain reaction (PCR) and rDNA Restriction-fragment length polymorphism (RFLP) analysis. Phylogenetic analysis of the Internal transcribed spacer (ITS) regions suggests that the isolates form a distinct group (named group 'E') situated within the Gaeumannomyces – Phialophora complex between the branch of the G. graminis varieties and Gaeumannomyces incrustans / Magnaporthe poae . Isolates of group E produced lobed hyphopodia and were shown in biotests to be non-pathogenic to wheat, oats, Italian Ryegrass and Chewings Fescue, suggesting it is a benign parasite which colonizes cereals or grasses without destroying vascular tissue. Furthermore, curved phialospores could be found. Summarizing the results presented, this new group could be classified as a new species of Phialophora . Although isolates of group E were found at only six of the 32 investigated locations, they composed up to 50% of total isolates of the Gaeumannomyces – Phialophora complex at these sites. Because of the non-pathogenic behaviour, the new group may be of value as biological control agents for pathogenic fungi.     

Nutritional Requirements of Blastocrithidia culicis,a Trypanosomatid with an Endosymbiont1

ABSTRACT. The symbiont-containing Blastocrithidia culicis from Aedes vexans, unlike most lower trypanosomatids cultivated in defined media, require only three amino acids: methionine, histidine, and arginine; only three vitamins: thiamin, nicotinamide, and riboflavin; and neither heme nor purine. The bacterium-like endosymbiont presumably provides the trypanosomatid's other essential nutrients.     

A new genus of African Karniellina (Orthoptera,Tettigoniidae, Conocephalinae,Conocephalini): integrating morphological,molecular and bioacoustical data

Melanoscirtes gen.n. is established within Karniellina. The members of this subtribe are small conocephaline bush crickets, confined to Africa. Melanoscirtes is erected on Phlesirtes kibonotensis, a species restricted to forest clearings and forest edge in the submontane and montane zones of Mt. Kilimanjaro. A subspecies, M. kibonotensis uguenoensis, is described from the North Pare mountains, a mountain range of the Eastern Arc adjacent to Mt. Kilimanjaro. Further species of Melanoscirtes occur on other mountain ranges of the northern branch of the Eastern Arc mountains of northern Tanzania and southern Kenya. The South Pare mountains harbour M. shengenae; the West Usambaras, M. usambarensis, and the Taita Hills, M. taitensis. All species and subspecies of Melanoscirtes exhibit a similar morphology and occupy analogous habitats on the respective mountains. The song patterns for all species found within this genus are very similar, and this, together with evidence from molecular data, suggests that allopatric speciation is the reason for the biogeographic pattern found in this genus. A key for the subspecies and species of Melanoscirtes is provided.     

Temperature,size, reproductive allocation,and life‐history evolution in a gregarious caterpillar

The present study aimed to investigate the relationship between growth rate, final mass, and larval development, as well as how this relationship influences reproductive trade‐offs, in the context of a gregarious life‐style and the need to keep an optimal group size. We use as a model two sympatric populations of the pine processionary moth Thaumetopoea pityocampa, which occur in different seasons and thus experience different climatic conditions. Thaumetopoea pityocampa is a strictly gregarious caterpillar throughout the larval period, which occurs during winter in countries all over the Mediterranean Basin. However, in 1997, a population in which larval development occurs during the summer was discovered in Portugal, namely the summer population (SP), as opposed to the normal winter population (WP), which coexists in the same forest feeding on the same host during the winter. Both populations were monitored over 3 years, with an assessment of the length of the larval period and its relationship with different climatic variables, final mass and adult size, egg size and number, colony size, and mortality at different life stages. The SP larval period was reduced as a result of development in the warmer part of the year, although it reached the same final mass and adult size as the WP. Despite an equal size at maturity, a trade‐off between egg size and number was found between the two populations: SP produced less but bigger eggs than WP. This contrasts with the findings obtained in other Lepidoptera species, where development in colder environments leads to larger eggs at the expense of fecundity, but corroborates the trend found at a macro‐geographical scale for T. pityocampa, with females from northern latitudes and a colder environment producing more (and smaller) eggs. The results demonstrate the importance of the number of eggs in cold environments as a result of an advantage of large colonies when gregarious caterpillars develop in such environments, and these findings are discussed in accordance with the major theories regarding size in animals. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 340–349.     

Phylogeny and systematics of the Pachychilidae of mainland South‐East Asia – novel insights from morphology and mitochondrial DNA (Mollusca,Caenogastropoda, Cerithioidea)

Pachychilid gastropods are a conspicuous element of the freshwater macro‐invertebrate fauna of South‐East Asia. In this region, three spatially separated groups of pachychilids can be differentiated mostly by means of their brooding strategy. The largest group comprises about 100 described species and displays an extended Sundaland distribution that ranges from north‐east India in the west to southern China in the east and Borneo in the south‐east. The most conspicuous synapomorphy shared by females is a subhaemocoelic brood pouch in which developing embryos are retained. Mitochondrial phylogenies based on partial sequences of the genes cytochrome oxidase C subunit I (COI) and 16S rRNA (16S) support the monophyly of this group of subhaemocoelic brooders. Amongst them, the two genera Brotia and Paracrostoma form a sister pair of clades both together forming the sister taxon of a third clade. This third clade itself is split into three subclades, which occupy separate ranges except for the overlap of two of them in Borneo. The subclades comprise species from (A) Thailand, Cambodia, and northern Borneo; (B) Java and south‐western Borneo; and (C) Vietnam and southern China. In contrast with their spatial structuring, all species share a widely corresponding anatomy. Characteristic key features are a pallial oviduct with a seminal receptacle and an embryonic shell with a smooth, dome‐like inflated apex. Differences in the histology of the pallial oviduct are not congruent with phylogenetic patterns as suggested by the mitochondrial trees. Given the lack of obvious distinguishing morphological characteristics, all species of the subclades A to C are assigned to a single genus, Sulcospira, with Adamietta as a junior synonym.     

A brittle star bed from the Miocene of Patagonia, Argentina

Martínez, S., del Río, C.J. & Pérez, D.E. 2010: A brittle star bed from the Miocene of Patagonia, Argentina. Lethaia , Vol. 43, pp. 1–9.
As a consequence of the extremely poor fossil record of brittle stars, every new discovery is important. The Miocene example studied herein involves the recently described species Ophiocrossota kollenbergorum Caviglia, Martínez & del Río recovered from the Chenque Formation of southeastern Argentina. The information used here is derived from unpublished data and a new record from two discrete, thin, monospecific patches. The main taphonomic features of the patches, namely the presence of specimens concordant with bedding planes, (with either aboral or oral side upwards), and the good preservation of the delicate discs (ca. 6 mm wide on average), and the preservation of un-oriented arms complete with fragile tips (not wider than 0.2 mm), point to a suddenly buried census assemblage. Although broken or isolated arms were found, this is attributed to the erosive environmental conditions of the abrasion platform where the studied exposure is located today. Size frequency distributions suggest that both patches were buried at different seasons. Observed densities are 77 and 143 individuals/m², and distances between individuals are random. The arm length/disc diameter ratio indicates that Ophiocrossota kollenbergorum may have been an epifaunal surface dweller. No signs of predation (such as regenerated arms), were identified.     

European plants with C4 photosynthesis: geographical and taxonomic distribution and relations to climate parameters

A survey of C₄ plants in Europe was performed with 216 species based on information in the literature and new studies. C₄ species were found in 10 families: the eudicots Amaranthaceae, Chenopodiaceae, Euphorbiaceae, Molluginaceae, Nyctaginaceae, Polygonaceae, Portulacaceae and Zygophyllaceae and the monocots Cyperaceae and Poaceae. The majority of the C₄ species belong to four families, Amaranthaceae (23), Chenopodiaceae (65), Cyperaceae (27) and Poaceae (88). In central and southern Europe, the abundance of native C₄ plants varied between 44 and 88% of total C₄ plants occurring, the rest being invasive C₄ species. The occurrence of total C₄ species, C₄ monocots and C₄ Chenopodiaceae was assessed for five major phyto‐geographical regions of Europe (north‐west, north‐east, central, south‐west, and south‐east). The abundance of C₄ plants of total C₄ dicots, C₄ Chenopodiaceae, total C₄ monocots, C₄ Poaceae and C₄ Cyperaceae was related to the climatic variables of annual mean daily temperature, annual precipitation and DeMartonne's aridity index. The abundance of total C₄ plants decreases with increasing temperature and expression of aridity (decreasing aridity index) and is not correlated with precipitation. The abundance of total C₄ dicots and C₄ Chenopodiaceae is correlated with precipitation and aridity but not temperature, whereas the abundance of total C₄ monocots, C₄ Poaceae and C₄ Cyperaceae is correlated with temperature and aridity but not precipitation. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 283–304.     

Enrichment of human bone marrow mononuclear phagocytes and characterization of macrophage subpopulations by immunoenzymatic double staining

In order to isolate and enrich bone marrow mononuclear phagocytes, we performed magnetic-activated cell sorting using beads coupled to a monoclonal antibody directed against the monocyte/macrophage surface molecule CD14. Co-localization of antigens in single cells was achieved by combining an alkaline phosphatase--anti-alkaline phosphatase and an avidin--biotin complex immunoassay, avoiding the use of peroxidase. Bone marrow macrophages were first labelled by the monoclonal antibody PG-M1 (anti-CD68). Subsequently, cytoplasmic and/or surface double staining by the monoclonal antibodies against HLA-DR and Mac-2 antigen or the lectin GSA-I-B4 was carried out. Whereas HLA-DR was co-expressed by the great majority of PG-M1+ macrophages (84.9% +/- 6.9%), only a subpopulation exhibited Mac-2 (69.9% +/- 5.9%) antigen or galactoside structures detected by GSA-I-B4 (65.0% +/- 6.7%). The latter result differed only slightly from the percentage of GSA-I-B+4 macrophages determined in a previous comparative immunomorphometrical study. Therefore, using our method of isolation and enrichment by magnetic-activated cell sorting, only a negligible portion of macrophages is apparently stimulated, as shown by GSA-I-B4 staining. This methodology seems to be a valuable tool for further studies on the monocyte--macrophage system. © 1998 Chapman & Hall