Role of β1 Integrins in Cell Spreading and Migration of Human Nevomelanocytes and Dysplastic Nevi Cells on Collagen Type IV and Laminin

We characterized β1 integrin subunit expression on three different cultures of benign human nevomelanocytes (NMC) and on four different cell cultures of human dysplastic nevus (DN) cells by flow cytometry analysis and examined their role in mediating cell spreading and migration on collagen type IV (CN IV) and laminin (LN) coated substrates by using a quantitative video image analysis system. The seven human NMC and DNC cultures expressed heterogeneous levels of β1, α2, α3 and α6 integrin subunits. Image analysis showed that a significant increase (P<0.001) in cell spreading and migration of the DN cells was induced on increasing coating concentrations of CN IV and LN. However, the NMC did not show an increase in cell spreading or migration on these substrates when compared to the substrates coated with denatured BSA only. The CN IV-induced cell spreading of the DN cells was significantly inhibited by anti-β1 mAb (AIIB2), anti-α2 mAb (P1E6), or anti-α3 mAb (P1B5), but not by mAb against α6 integrin subunit (GoH3). The DN cell spreading on LN was not significantly inhibited by these mAbs. In contrast, the migration of the DN on CN IV and LN was significantly inhibited by anti-β1 mAb, anti-α2 mAb, anti-α3 mAb and anti-α6 mAb. These data suggest that the α2 and α3 subunit are important for cell spreading of the DN on CN IV, although they are less important in cell spreading on the extracellular matrix component LN. The α2, α3 and α6 integrin subunits are important for the migration of DN cells on both CN IV and LN.     

Organotypic Culture of Human Skin to Study Melanocyte Migration

An ex vivo model system was developed to investigate melanocyte migration. Within this model system, melanocytes migrate among other epidermal cells in the epibolic outgrowth of skin explants. This process is initiated by loss of contact inhibition of epidermal cells at the rim of the explants and by locally produced chemotactic factors. Punch biopsies provided explants of reproducible diameter. Optimal culture conditions include medium consisting of Dulbecco's Minimal Essential Medium containing 10% inactivated normal human serum and placement of explants epidermal side up at the air-liquid interphase. Within 7 days, epidermal cells completely surround the explant. Approximately 3 days after the onset of keratinocyte migration, melanocytes distribute themselves within the newly formed epidermis. Throughout the 7-day culture period, melanocytes and keratinocytes show maintenance of subcellular morphology, and the dermo-epidermal junction remains intact. Melanocyte migration was quantified using immunoperoxidase staining in combination with light microscopy and computer-aided image analysis. Preliminary results using the model system to compare migration in control and nonlesional vitiligo skin indicate that no inherent migration defect is responsible for impaired repigmentation of vitiligo lesions. The organotypic culture model system allows for investigations on melanocytes within their environment of autologous epidermal and dermal components, closely resembling in vivo circumstances in human skin.     

Changes in temperature, not photoperiod, control the pattern of adult eclosion in the tsetse, Glossina morsitans

Abstract. The timing of adult eclosion in tsetse, an event that normally occurs in mid-afternoon, is regulated by the daily cycle of temperature elevation. If a temperature cycle is maintained, the rhythm of eclosion persists under continuous light or continuous darkness. Artificially shifting the temperature peak to the scotophase results in a concomitant shift in the eclosion pattern. Daily temperature variations as small as 0.4°C are sufficient to establish the rhythm. Eclosion activity tracks the temperature peak, even if the pulses are of short duration (4 h) or with irregular frequencies of 12 or 36 h. The temperature-induced rhythm offers a simple mechanism for separating females and males. Individuals that pupariate on the same day eclose as adults over a 4–5 day period at 25°C, and in such collections, females are the first to eclose. This distinction makes it possible to collect samples of predominately one sex, a feature that may facilitate the collecting of males for use in the sterile-male technique.     

Phylogeny and classification of the Phengaris–Maculinea clade (Lepidoptera: Lycaenidae): total evidence and phylogenetic species concepts

Abstract.  Total evidence analysis, based on a combination of morphological and ecological characters with two mitochondrial sequences (cytochrome c oxidase subunits I and II) and one nuclear (elongation factor-1α) sequence, provides a new phylogeny of the uniquely obligate ant parasitic Phengaris–Maculinea butterflies. The clade, including all species of Maculinea and Phengaris , is very stable and well supported. However, various analyses suggest that either Phengaris or Maculinea is not monophyletic with regard to the other, which necessitates generic reclassification of the clade. Application of the diagnostic and monophyletic 'phylogenetic' species concepts leads to species-level reclassification, including ten species ( P. alcon comb.n. including ' P. rebeli ', P. daitozana , P. albida , P. atroguttata , P. kurentzovi comb.n. , P. nausithous comb.n. , P. teleius comb.n. , P. arion comb.n. , P. arionides comb.n. , P. takamukui comb.n .) and one unresolved metaspecies (' P. cyanecula ' comb.n .) in four monophyletic species groups. The existence of further or additional cryptic species is possible within P. nausithous and P. teleius . Maculinea Van Eecke, 1915 syn.n. is considered a junior synonym of Phengaris Doherty, 1891.     

A new genus of xenophyophores (Foraminifera) from Japan Trench: morphological description,molecular phylogeny and elemental analysis

The deep‐sea floor is inhabited by a number of unusual and enigmatic taxa, unknown in shallow waters. These include the xenophyophores, a group of giant protists that construct fragile agglutinated tests. Here, we describe Shinkaiya lindsayi gen. et sp. nov. , a new xenophyophore collected by the submersible Shinkai 6500 at a depth of 5435 m near the Japan Trench. The phylogenetic analysis performed on its complete small‐subunit ribosomal DNA (SSU rDNA) sequence confirms that Sh. lindsayi sp. nov. is a foraminiferan that is closely related to another xenophyophore, Syringammina corbicula Richardson, 2001, and to a monothalamous (single‐chambered) foraminiferan Rhizammina algaeformis Brady, 1879. In terms of morphology, the new genus resembles Syringammina, but its test wall is thicker, softer, and more weakly cemented. Moreover, the SSU rDNA sequences of the two genera are highly divergent. Mass spectra analyses reveal unusually high concentrations of some elements, such as lead, uranium, and mercury. The granellare system (the cytoplasm and the organic sheath that encloses it) is apparently devoid of barite crystals, which are usually abundant as intracellular inclusions in xenophyophores, but is rich in mercury (with 12 times the concentration of mercury found in the surrounding sediment). Fecal pellets retained within a tubular system (stercomare) concentrate heavy metals, including lead and uranium (respectively, two and six times more than that of the sediment). Based on a comparison of the compositions of the agglutinated test wall, the granellare, the stercomare, and the surrounding sediment, we discuss the impact of xenophyophores on their habitat. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 455–464.     

Osteology and ecology of Megantereon cultridens SE311 (Mammalia; Felidae; Machairodontinae), a sabrecat from the Late Pliocene – Early Pleistocene of Senéze, France

Megantereon cultridens was a derived, Late Pliocene to Early Pleistocene sabrecat, and although fossils of animals referred to the genus and species have been found at several locations throughout Eurasia, most are fragmentary. However, the specimen SE311 from Senéze in France represents an almost complete and well-preserved skeleton, and this is only known from very few other sabrecats, thus providing a rare glimpse into the full anatomy of an unusual and derived sabrecat. In this monograph, we provide a complete overview of the anatomy of Megantereon cultridens SE311, and compare it with extant large felids, and the few other derived sabrecats from which ample fossil material is known, although most frequently representing several specimens. SE311 was a large specimen of M. cultridens and would have had a body mass of 100–110 kg and a head–body length or around 160 cm, which is similar to a small lioness or large male jaguar. Megantereon sp. were sexually dimorphic, and the size of SE311 suggests that it was a male. As with several other derived sabrecats, it was powerfully built, and had particularly robust forequarters with very well-developed muscle attachment sites, indicating a powerful forelimb and shoulder musculature. The neck was proportionally much longer than in extant felids, and the thoracic and particularly lumbar region was proportionally shorter, mimicking the condition in other derived sabrecats from which large parts of the vertebral column is known. Megantereon probably lived in open-forest environments and preyed on cervids, which were dispatched with a shearing bite from the hypertrophied and blade-like upper canines to the throat of the prey, while the prey was held immobile with the massive forelimbs, thus minimizing the risk of damage to the fangs.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 , 833–884.     

The two-horned chamaeleons of East Africa

There have been numerous attempts to resolve the taxonomy of the two-horned chamaeleons of East Africa. However, the high levels of intraspecific variation and reported sympatry of morphologically distinct taxa indicate that their current classification is unsatisfactory. Tissue samples were collected from specimens from most mountain massifs (excluding the Nguu) where two-horned chamaeleons are known to occur and were used to sequence partial 12S and 16S rRNA, as well as ND2 mtDNA genes. These specimens and further museum material were used to review morphological variation and to define discriminating characters for each taxon. Phylogenetic analyses of gene sequences show clear genetic divergence between allopatric populations, although two lineages occur in sympatry in the East Usambara Mountains, and is supported by divergent morphology. In light of these results a formal revision of the taxonomy of all East African two-horned chamaeleons is proposed and seven species are recognized ( Kinyongia boehmei , K. fischeri , K. matschiei , K. multituberculata , K. tavetana , K. uluguruensis and K. vosseleri ). These taxa form a monophyletic group except for K. uluguruensis , which seems to be more closely related to one-horned species. Most of these taxa have been previously described and subsequently reduced to synonyms. Two other previously described two-horned taxa are not recognized as valid: Chamaeleo tornieri is considered species inquiriendae , and C. fischeri werneri is placed in synonymy with K. multituberculata . A dichotomous key is provided for the identification of these taxa and some aspects of their conservation, ecology and evolutionary origins are also discussed.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 367–391.