Morphology and development of the Portuguese man of war, Physalia physalis

The Portuguese man of war, Physalia physalis, is one of the most conspicuous, but poorly understood members of the pleuston, a community of organisms that occupy a habitat at the sea-air interface. Physalia physalis is a siphonophore that uses a gas-filled float as a sail to catch the wind. The development, morphology, and colony organization of P. physalis is very different from all other siphonophores. Here, we look at live and fixed larval and juvenile specimens, and use optical projection tomography to build on existing knowledge about the morphology and development of this species. We also propose a framework for homologizing the axes with other siphonophores, and also suggest that the tentacle bearing zooids should be called tentacular palpons. Previous descriptions of P. physalis larvae, especially descriptions of budding order, were often framed with the mature colony in mind. However, we use the simpler organization of larvae and the juvenile specimens to inform our understanding of the morphology, budding order, and colony organization in the mature specimen. Finally, we review what is known about the ecology and lifecycle of P. physalis.

Morphology and development of the Portuguese man of war, Physalia physalis

The Portuguese man of war, Physalia physalis, is a siphonophore that uses a gas-filled float as a sail to catch the wind. It is one of the most conspicuous, but poorly understood members of the pleuston, a community of organisms that occupy a habitat at the sea-air interface. The development, morphology, and colony organization of P. physalis is very different from all other siphonophores. Here, we propose a framework for homologizing the axes with other siphonophores, and also suggest that the tentacle bearing zooids should be called tentacular palpons. We also look at live and fixed larval and non-reproductively mature juvenile specimens, and use optical projection tomography to build on existing knowledge about the morphology and development of this species. Previous descriptions of P. physalis larvae, especially descriptions of budding order, were often framed with the mature colony in mind. However, we use the simpler organization of larvae and the juvenile specimens to inform our understanding of the morphology, budding order, and colony organization in the mature specimen. Finally, we review what is known about the ecology and lifecyle of P. physalis.

The First Workers of the Ant Camponotus obscuripes Are a Different Allometric Morph with Relatively Long Antennae to Communicate with Other Larger Colony Members

The first workers produced by an ant queen with a claustral founding mode are much smaller than the workers after the second generation and are thus called “nanitics.” These nanitics shoulder the initial fate of the colony and thus may be different morphometric morph from the other workers in mature colony to optimize the survival of their own colony. We report here that, in the ant Camponotus obscuripes Mayr, the allometric rules of the nanitics are different from those of other workers in mature colonies, suggesting that the nanitics constitute an independent caste as with soldiers or queens in other species. In addition, the antennae of the nanitics show the minimum absolute length-difference with the mother queen compared to the other traits measured. This result suggests that this small size difference enables C. obscuripes nanitics to communicate with the other members of the colony. Our results indicate that polymorphic societies affect the growth rules of workers.

Biofilm Dispersal of Neisseria subflava and Other Phylogenetically Diverse Oral Bacteria

ABSTRACT Polystyrene petri dishes containing liquid medium were inoculated with single-cell suspensions of a fresh clinical isolate of Neisseria subflava and were incubated under conditions of low vibration. N. subflava colonies grew firmly attached to the surface of the dish, while the broth remained clear. Growing colonies released cells into the medium, resulting in the appearance of 102 to 104 small satellite colonies attached to the surface of the dish in an area adjacent to each mature colony after 24 h. Satellite colonies grew in patterns of streamers shaped like jets and flares emanating from mature colonies and pointing toward the center of the dish. This dispersal pattern evidently resulted from the surface translocation of detached biofilm cells by buoyancy-driven convection currents that were generated due to slight temperature gradients in the medium. Streamers of satellite colonies ranged from 2 to >40 mm in length. Satellite colonies in very long streamers were relatively uniform in size regardless of their distance from the mature colony, suggesting that mature colonies released single cells or small clusters of cells into the medium and that the detachment, surface translocation, and subsequent surface reattachment of released cells were a transitory process. Incubation of N. subflava single cells in a perfused biofilm fermentor resulted in a large spike of the number of CFU in the perfusate after 9.5 h of growth, consistent with a rapid release of cells into the medium. Biofilm colonies of several other phylogenetically diverse oral bacteria, including Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Streptococcus mitis, and a prevalent but previously uncultured oral Streptococcus sp., exhibited similar temperature-dependent dispersal patterns in broth culture. This in vitro spreading phenotype could be a useful tool for studying biofilm dispersal in these and other nonflagellated bacteria and may have physiological relevance to biofilm dispersal in the oral cavity.

Surface phenotype of clonogenic cells in acute myeloid leukemia defined by monoclonal antibodies

Colony-forming cells in ten cases of acute myeloid leukemia (AML) were studied with six cytotoxic monoclonal antibodies that react with antigens expressed at discrete stages of differentiation of normal and leukemic hematopoietic cells. The reactivity of the whole leukemic population was measured by indirect immunofluorescence, and the reactivity of the colony-forming cells was established by complement- mediated cytotoxicity and by fluorescence activated cell sorting. Comparison of the immunofluorescent reactivity with cytotoxicity and cell sorting showed that colony-forming cells were found within a fraction of the leukemic subpopulations that expresses these antigens. This finding implies that immunofluorescence reactivity of the total leukemic population does not necessarily predict the phenotype of the clonogenic cells. When the surface phenotype of the clonogenic leukemic cells was compared to that previously established for normal marrow hemopoietic clonogenic cells, several patterns were seen: (1) in four of ten cases, the clonogenic cells expressed a phenotype like that of relatively mature normal granulocyte-macrophage colony-forming cells (late CFU-GM) or, (2) in two cases, a phenotype similar to the less mature colony-forming cells (early CFU-GM or CFU-GEMM), and (3) in four cases, a composite phenotype of early and late CFU-GM. Thus, the level of impairment of differentiation in AML may vary from case to case. In those cases phenotypically similar to the late CFU-GM, it may be possible to separate leukemic clonogenic cells from less mature normal clonogenic cells using monoclonal antibodies selectively cytotoxic for the late CFU-GM.

Surface phenotype of clonogenic cells in acute myeloid leukemia defined by monoclonal antibodies

Colony-forming cells in ten cases of acute myeloid leukemia (AML) were studied with six cytotoxic monoclonal antibodies that react with antigens expressed at discrete stages of differentiation of normal and leukemic hematopoietic cells. The reactivity of the whole leukemic population was measured by indirect immunofluorescence, and the reactivity of the colony-forming cells was established by complement- mediated cytotoxicity and by fluorescence activated cell sorting. Comparison of the immunofluorescent reactivity with cytotoxicity and cell sorting showed that colony-forming cells were found within a fraction of the leukemic subpopulations that expresses these antigens. This finding implies that immunofluorescence reactivity of the total leukemic population does not necessarily predict the phenotype of the clonogenic cells. When the surface phenotype of the clonogenic leukemic cells was compared to that previously established for normal marrow hemopoietic clonogenic cells, several patterns were seen: (1) in four of ten cases, the clonogenic cells expressed a phenotype like that of relatively mature normal granulocyte-macrophage colony-forming cells (late CFU-GM) or, (2) in two cases, a phenotype similar to the less mature colony-forming cells (early CFU-GM or CFU-GEMM), and (3) in four cases, a composite phenotype of early and late CFU-GM. Thus, the level of impairment of differentiation in AML may vary from case to case. In those cases phenotypically similar to the late CFU-GM, it may be possible to separate leukemic clonogenic cells from less mature normal clonogenic cells using monoclonal antibodies selectively cytotoxic for the late CFU-GM.

Studies on Graminicolous Species of Phyllachora Fckl. III.. The relationship of certain Scolecospores to species of Phyllachora

The present study and a survey of literature showed that of the various spore types associated with species of Phyllachora, scolecospores typical of the form genus Leptostromella were most common. Examination has shown that certain spore types claimed as imperfect states of Phyllachora species are actually spores of hyperparasites. Evidence that the scolecospores belong to the Phyllachora species with which they are associated has been gathered. Studies on the development of P. parilis showed that the scolecospores associated with the perithecia of this species were genetically related to it. Attempts to germinate the scolecospores associated with three species of Phyllachora were unsuccessful. Similarly, when scolecospores 'were used as inoculum, test plants did not become infected. When ascosporic inoculum were used, however, infection occurred. Only one type of mycelium was found in each infection court, and pycnidia and perithecia developed from this in close association. Consequently, although the scolecosporous pycnidia developed prior to the perithecia, both types of fructification occurred in individual Phyllachora colonies. Within each mature colony the tissues of the pycnidia, perithecia, and clypeus became fused and were indistinguishable from one another. The development of the pycnidium and scolecospores is described, and it is shown that a different species of Leptostromella is associated with each different Phyllachora species. The Leptostromella species can be distinguished especially by the morphology of their sporophores. When it was shown that the morphology of the Leptostromella associated with each Phyllachora species was distinctive and constant, it was possible to assess the frequency and distribution of these associations. With some species of Phyllachora the association occurred in all specimens, while in others it was not as frequent. Always, however, the distribution of the association was as widespread as the species of Phyllachora concerned. It was noted that hyperparasites were able to parasitize the Leptostromella states as readily as the ascal states of various species of Phyllachora. The function of the scolecospores is not known, but it is suggested that they may be spermatia.