Living gephyrocapsa protohuxleyi McIntyre in the gulf of Elat ('AQABA)

Coccolithophore assemblages in the Gulf of Elat contain living Geopyrocapsa protohuxleyi hitherto assumed to have been extinct at least since 75, 000 years B.P.     

A cellular 57 kDa protein binds to two regions of the internal translation initiation site of foot-and-mouth disease virus

A ribosome-associated 57 kDa protein from rabbit reticulocytes was linked to the internal translation initiation site of foot-and-mouth disease virus by mild UV-irradiation. Binding studies with different RNA fragments revealed that this protein interacts with two distinct sites within the translational control region. One site is located approximately 400 nucleotides upstream from the translational start codon and the second binding site could be confined to 60 nucleotides preceding this codon. Both sequences coincide with hairpin structures at the two opposite ends of a secondary structure model of the internal ribosomal entry site proposed by Pilipenko et al. [(1989) Nucleic Acids Res. 17, 5701-5711].     

Murine Norovirus Transcytosis across an In Vitro Polarized Murine Intestinal Epithelial Monolayer Is Mediated by M-Like Cells

Noroviruses (NoVs) are the causative agent of the vast majority of nonbacterial gastroenteritis worldwide. Due to the inability to culture human NoVs and the inability to orally infect a small animal model, little is known about the initial steps of viral entry. One particular step that is not understood is how NoVs breach the intestinal epithelial barrier. Murine NoV (MNV) is the only NoV that can be propagated in vitro by infecting murine macrophages and dendritic cells, making this virus an attractive model for studies of different aspects of NoV biology. Polarized murine intestinal epithelial mIC_cl2 cells were used to investigate how MNV interacts with and crosses the intestinal epithelium. In this in vitro model of the follicle-associated epithelium (FAE), MNV is transported across the polarized cell monolayer in the absence of viral replication or disruption of tight junctions by a distinct epithelial cell with microfold (M) cell properties. In addition to transporting MNV, these M-like cells also transcytose microbeads and express an IgA receptor. Interestingly, B myeloma cells cultured in the basolateral compartment underlying the epithelial monolayer did not alter the number of M-like cells but increased their transcytotic activity. Our data demonstrate that MNV can cross an intact intestinal epithelial monolayer in vitro by hijacking the M-like cells'' intrinsic transcytotic pathway and suggest a potential mechanism for MNV entry into the host.     

Endoreduplication Occurs during Pod Wall Development in Temperate Grain Legumes

Differentiation to a specialized function in plant tissue isassociated with an increase in the DNA content of the cellsover the diploid state. Using flow cytometry, ploidy levelswere assessed during pod development in three white lupin genotypesunder three environmental conditions and in other lupin speciesand temperate grain legumes in one environmental condition.Endoreduplication was found in the pod walls of all genotypesstudied. Higher ploidy levels coincided with maximal growthof the pod. DNA replication was not related to the proportionof the pod that comprised walls. Endoreduplication also occurredin other temperate grain legumes with at least two DNA duplicationsduring the development of the pod walls. The biological significanceof endoreduplication in the pod walls of grain legumes is unknown,but could be related to the storage function of these organs.Copyright2000 Annals of Botany Company Lupinus species, Pisum sativum, Phaseolus vulgaris, Vicia faba, pod wall development, ploidy level, flux cytometry, Bis-benzimide Hoechst 33258     

Structure and ultrastructure of spermatozoa and spermiogenesis in three species of Lucilia Robineau‐desvoidy, 1830 (Diptera: Calliphoridae)

Morphology of male internal reproductive organs, spermatozoa, and spermiogenesis of the blow‐flies Lucilia cuprina, Lucilia eximia, and Lucilia peruviana is first described here, using light and transmission electron microscopy. Spermiogenesis follows the characteristics described for others insect species. The spermatozoa of L. cuprina are similar to those described for other Brachycera. However, in L. eximia and L. peruviana, some differences were found. In L. cuprina and L. eximia species, the spermatozoa are long and thin, measuring about 211 μm and 146 μm in length, of which the head region measures approximately 19 μm and 17 μm, respectively. A polymorphism was observed in L. cuprina and L. eximia spermatozoa. In all three species, the head includes a monolayered acrosome with electron‐lucent material. The shape of the nucleus, in cross sections, varies from circular to oval with completely condensed chromatin. Implantation of the axoneme was observed in the middle region of the nucleus, known as the “peg” region. In the next region, the beginning of two mitochondrial derivatives of similar diameter and different lengths in L. cuprina and only one in L. eximia and L. peruviana was observed. In the overlap region, the following structures were observed: nucleus, centriolar adjunct, mitochondrial derivatives, and axoneme. The axoneme is of a conventional insectan type with a 9 + 9 + 2 microtubular arrangement. The male internal reproductive tract consists of testis, deferent ducts, a strongly developed seminal vesicle, accessory glands, and ejaculatory duct. These features are consistent with the structural diversity of the dipteran reproductive tract and spermatozoa, comprising an essential tool for understanding the complex variations found in the Diptera. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc.