Development of cell surface saccharides on embryonic pancreatic cells

Using a battery of seven lectin-ferritin conjugates as probes for cell surface glycoconjugates, we have studied the pattern of plasmalemmal differentiation of cells in the embryonic rat pancreas from day 15 in utero to the early postpartum stage. Our results indicate that differentiation of plasmalemmal glycoconjugates on acinar, endocrine, and centroacinar cells is temporally correlated with development and is unique for each cell type, as indicated by lectin-ferritin binding. Specifically, (a) expression of adult cell surface saccharide phenotype can be detected on presumptive acinar cells as early as 15 d in utero, as indicated by soybean agglutinin binding, and precedes development of intracellular organelles characteristic of mature acinar cells; (b) maturation of the plasmalemma of acinar cells is reached after intracellular cytodifferentiation is completed, as indicated by appearance of Con A and fucoselectin binding sites only at day 19 of development; conversely, maturation of the endocrine cell plasmalemma is accompanied by "loss" (masking) of ricinus communis II agglutinin receptors; and (c) binding sites for fucose lectins and for soybean agglutinin are absent on endocrine and centroacinar cells at all stages examined. We conclude that acinar, centroacinar, and endocrine cells develop from a common progenitor cell(s) whose plasmalemmal carbohydrate composition resembles most closely that of the adult centroacinar cell. Finally, appearance of acinar lumina beginning at approximately 17 d in utero is accompanied by differenetiation of apical and basolateral plasmalemmal domains of epithelial cells, as indicated by enhanced binding of several lectin-ferritin conjugates to the apical plasmalemmal, a pattern that persists from this stage through adult life.     

Mutant dn Influences Dry Matter Distribution, Assimilate Partitioning and Flowering in Lathyrus odoratus L.

The flowering mutant dn in sweet pea was used as a tool to study¹⁴C-assimilate and dry matter partitioning with respect to nutrientdiversion theories on the control of flower initiation. Wildtype plants (Dn^h) are photoperiodic and exhibit late floweringand profuse basal branching in short days while mutant plants(dn) are day neutral, early flowering and devoid of basal laterals.In short days, dn plants exported a significantly greater proportionof assimilate acropetally than (Dn^h) plants and the upper portionof dn plants had a greater dry weight. These differences werereduced dramatically when basal laterals were excised regularlyfrom the (Dn^h) plants although the difference in flowering remained.However, the effect of dn on resource allocation within theapical region may be more important in regard to flowering thanthe effect on acropetal versus basipetal movement. In shortdays, the dn plants partitioned significantly more resourcesinto their internodes and petioles, and less into their leaflets,than Dn^h plants as shown by dry weight and ¹⁴C-assimilate measurements.These differences were apparent from as early as node 7 up tothe node of flower initiation in dn plants (node 30) and theywere not eliminated by removal of basal laterals from Dn^h plants.Differences between dn and Dn^h plants in partitioning and floweringwere largely eliminated under long days. The fact that in thisspecies a single gene influences both resource allocation andflower initiation lends further support to nutrient diversionhypotheses on the control of flowering. Key words: Assimilate partitioning, branching, flowering, mutant, sweet pea     

Regulation of Internodal Extension in Avena Shoots by the Inflorescence, Nodes, Leaves, and Intercalary Meristem

It has been found in recent studies that the inflorescence and nodes (node-pulvini) are the primary sources for native gibberellins in the Avena shoot, and that GA₃ is the predominant gibberellin in the inflorescence. In the present work, linear growth of next-to-last internode is drastically reduced by removal of the inflorescence and last leaf. This growth is completely abolished when the nodes are also excised. It is restored fully by the addition of GA₃ when the nodes are present, and restored only partially when the nodes are deleted. Internodal growth in Avena stem segments with basal node present is also restored by native GA₃-like substances extracted from Avena inflorescences and partially purified by silica gel partition column chromatography. Evidence from these studies, taken in toto, indicates that the inflorescence, nodes, and leaves supply gibberellins, leaves supply substrate, and nodes modulate the gibberellin growth response in next-to-last Avena internodes.     

Habitat selection at multiple spatial scales by foraging Glossy Black‐cockatoos

Abstract: Habitat selection among vertebrates entails decision making at a number of spatial scales. An understanding of factors influencing decisions at each of these scales is required for the effective management of wildlife populations. This study investigates the foraging ecology of a population of Glossy Black‐cockatoos in central New South Wales. We took advantage of the characteristic feeding sign produced by Glossy Black‐cockatoos to examine factors influencing habitat selection at multiple spatial scales. Birds preferred to forage at sites where food was abundant and avoided open sites where the predation risk may be greater. Their two food species, Allocasuarina diminuta and Allocasuarina gymnanthera, differed in profitability (kernel intake rate as measured by the ratio of seed weight to total seed and cone weight), as did trees within a species. Both species were utilized extensively, although foraging intensity was greater at sites where the more profitable species was present. In order to maximize their food intake, birds selected individual trees on the basis of cone abundance and profitability. Cones produced in the previous year were preferred.     

Do pollinators influence seed-set in Banksia paludosa Sm. and Banksia spinulosa R. Br.?

The consequences of observed variations in pollinator activity for plant reproduction depend on the breeding system of the plant and also on whether pollination is a resource in short supply. These factors are frequently assumed rather than tested. In bagging experiments with Banksia paludosa in heath and B. spinulosa var. spinulosa in woodland, the present study demonstrated that seed-set does not occur by autogamy and that pollinators are indeed necessary. Experimental addition of outcrossed pollen to inflorescences failed to produce any increase in the mean number of seeds per inflorescence, measured for non-barren inflorescences, for either species. However, in B. paludosa, the addition of pollen increased the numbers of inflorescences that set seed from 20% (controls) to 45% (pollen-added treatment). This suggests either unusual patterns of pollen movement among and within plants or control of the pattern of seed-set within a plant. Pollen additions failed to alter seed-set in B. spinulosa. It is possible that a greater abundance of pollinators in the woodland ensures adequate pollination for these plants     

European society of intensive care medicine study of therapeutic hypothermia (32-35°C) for intracranial pressure reduction after traumatic brain injury (the Eurotherm3235Trial)

Background

Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates.

Methods/Design

This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae.

Discussion

Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa.

Trial Registration

ClinicalTrials.gov Identifier: NCT01255215     

Observations on the development and maintenance of the deep sea barnacle,Octolasmis aymonini geryonophila (Pilsbry)

Thirty-two pedunculate barnacles, O. a. geryonophila, were maintained in culture for a period of 2 yr in the laboratory. These barnacles were obtained from the pleopods and mouth parts of the giant marine isopod, Bathynomus giganteus, which had been collected, at a depth of 200 fathoms, in the Gulf of Mexico.

The carina, scutum, mandible and maxilla of adult barnacles were typical of deep water species. However, the tergum and labrum were intermediate between those of shallow and deep water species.

Adults 3.1–4.1 mm in length were cultured in sea water (15–19°C), and fed on benthic copepods such as Tisbe furcata and Laophonte sp. Three broods of nauplii from 8 barnacles were obtained in 2 yr. Larvae were reared on plankton collected from Coney Island waters in which nauplii reached Stage IV in 10–14 days at 16°C. Isochrysis galbana and Thalassiosira pseudonana individually or in combination maintained nauplii to Stage IV, but with very high mortality. The lack of spines on the carapace edge of the nauplii distinguishes this deep water species from the shallow water form, O. mulleri.