Cell to cell communication

Our knowledge regarding the nature and development of microbial biofilms has grown significantly since the first report of these communities by Antonie van Leeuwenhoek in the late 1600s. Nevertheless, most biofilm studies examine mono-species cultures, whereas nearly all biofilm communities in nature comprise a variety of microorganisms. The species that constitute a mixed biofilm and the interactions between these microorganisms critically influence the development and shape of the community. In this review, we focus on interactions occurring within a multi-species biofilm and their effects on the nature of the mixed community. In general, interspecies interactions involve communication, typically via quorum sensing, and metabolic cooperation or competition. Interactions among species within a biofilm can be antagonistic, such as competition over nutrients and growth inhibition, or synergistic. The latter can result in the development of several beneficial phenotypes. These include the promotion of biofilm formation by co-aggregation, metabolic cooperation where one species utilizes a metabolite produced by a neighboring species, and increased resistance to antibiotics or host immune responses compared to the mono-species biofilms. These beneficial interactions in mixed biofilms have important environmental, industrial, and clinical implications. The latter, for example, impacts the course and treatment of biofilm-related infections, such as those manifested in the lungs of cystic fibrosis patients. ª 2012 Federation of European Microbiological Societies FEMS Microbiol Rev 36 (2012) 990-1004 Published by Blackwell Publishing Ltd. All rights reserved

Motivation: The evolution of multicellular organisms is associated with increasing variability of molecules governing behavioral and physiological states. This is often achieved by Neuropeptides (NPs) that are produced in neurons from a longer protein, named neuropeptide precursor (NPP). The maturation of NPs occurs through a sequence of proteolytic cleavages. The difficulty in identifying NPPs is a consequence of their diversity and the lack of applicable sequence similarity among the short, functionally related NPs. Results: Herein, we describe NeuroPID, a machine-learning scheme that predicts Metazoan NPPs. NeuroPID was trained on hundreds of identified NPPs from the UniProtKB database. Some 600 features were extracted from the primary sequences and processed using support vector machines (SVM) and ensemble decision tree classifiers. These features combined biophysical, chemical and informational-statistical properties of NPs and NPPs. Other features were guided by the defining characteristics of the dibasic cleavage sites motif. NeuroPID reached 89-94% accuracy and 90-93% precision in cross-validation blind tests against known NPPs (with an emphasis on Chordata and Arthropoda). NeuroPID also identified NPP-like proteins from extensively studied model organisms as well as from poorly annotated proteomes. We then focused on the most significant sets of features that contribute to the success of the classifiers. We propose that NPPs are attractive targets for investigating and modulating behavior, metabolism and homeostasis, and that a rich repertoire of NPs remains to be identified. Availability: NeuroPID source code is freely available at

Abscission is an active process that enables plants to shed unwanted organs. Because the purpose of the flower is to facilitate pollination, it often is abscised after fertilization. We have identified an Arabidopsis ethylene-sensitive mutant, inflorescence deficient in abscission ( ida ), in which floral organs remain attached to the plant body after the shedding of mature seeds, even though a floral abscission zone develops. The IDA gene, positioned in the genomic DNA flanking the single T-DNA present in the ida line, was identified by complementation. The gene encodes a small protein with an N-terminal signal peptide, suggesting that the IDA protein is the ligand of an unknown receptor involved in the developmental control of floral abscission. We have identified Arabidopsis genes, and cDNAs from a variety of plant species, that encode similar proteins, which are distinct from known ligands. IDA and the IDA-like proteins may represent a new class of ligands in plants.

Plants may shed organs when they have been injured or served their purpose. The differential pattern of organ abscission in different species is most likely the result of evolutionary adaptation to a variety of life styles and environments. The final step of abscission-related cell separation in floral organs of wild-type Arabidopsis thaliana, which only abscises sepals, petals, and stamens, is controlled by INFLORESCENCE DEFICIENT IN ABSCISSION (IDA). Here, we demonstrate that Arabidopsis 35S:IDA lines constitutively overexpressing IDA exhibit earlier abscission of floral organs, showing that the abscission zones are responsive to IDA soon after the opening of the flowers. In addition, ectopic abscission was observed at the bases of the pedicel, branches of the inflorescence, and cauline leaves. The silique valves also dehisced prematurely. Scanning electron microscopy indicated a spread of middle lamella degradation from preformed abscission zone cells to neighboring cells. A transcript encoding an arabinogalactan protein (AGP) was upregulated in the 35S:IDA lines, and large amounts of AGP were secreted at the sites of abscission. AGP was shown to be a constituent of wild-type floral abscission zones during and soon after cell separation had been completed. We suggest that the restricted expression pattern of IDA precludes abscission of nonfloral organs in Arabidopsis.

Persistent difficulties in resolving clear lineages in diverging populations of prokaryotes or unicellular eukaryotes (protistan polyphyletic groups) are challenging the classical species concept. Although multiple integrated approaches would render holistic taxonomies, most phylogenetic studies are still based on single-gene or morphological traits. Such methodologies conceal natural lineages, which are considered “cryptic.” The concept of species is considered artificial and inadequate to define natural populations. Social organisms display differential behaviors toward kin than to nonrelated individuals. In “social” microbes, kin discrimination has been used to help resolve crypticity. Aggregative behavior could be explored in a nonsocial protist to define phylogenetic varieties that are considered “cryptic.” Two Entamoeba invadens strains, IP-1 and VK-1:NS are considered close populations of the same “species.” This study demonstrates that IP-1 and VK-1:NS trophozoites aggregate only with alike members and discriminate members of different strains based on behavioral and chemical signals. Combined morphological, behavioral/chemical, and ecological studies could improve Archamoebae phylogenies and define cryptic varieties. Evolutionary processes in which selection acted continuously and cumulatively on ancestors of Entamoeba populations gave rise to chemical and behavioral signals that allowed individuals to discriminate nonpopulation members and, gradually, to the emergence of new lineages; alternative views that claim a “Designer” or “Creator” as responsible for protistan diversity are unfounded.

Penulisan artikel ini bertujuan untuk mengetahui pengertian sel, struktur sel, fungsi sel, dan komunikasi sel. Metode penulisan menggunakan metode kajian pustaka (Library Research). Dari pembahasan dapat disimpulkan bahwa Sel merupakan unit terkecil yang menjadi dasar kehidupan dalam arti biologis. Semua fungsi kehidupan diatur dan berlangsung di dalam sel. Struktur sel terdiri atas Inti sel, Sitoplasma dan Membran Sel. Sel berfungsi untuk proses metabolisme dan komunikasi sel. Sel dapat berkomunikasi melalui kontak langsung baik pada hewan maupun tumbuhan yang memiliki junction (sambungan) sel dengan memberikan kontinuitas sitoplasmik di antara sel – sel yang berdekatan. Dalam hal ini, bahan pensinyalan yang larut dalam sitosol dapat dengan bebas melewati sel yang berdekatan.  Jaringan komunikasi antara satu sel dengan yang lain menghasilkan suatu koordinasi untuk    mengatur pertumbuhan, reproduksi, osmoregulasi, dan lain-lain pada berbagai jaringan maupun    organ. Sistem komunikasi ini selain dilakukan oleh sistem saraf, juga dilakukan oleh system endokrin atau bahkan sistem saraf bersama-sama dengansistem  endokrin  mengontrol  aktivitas  organ atau jaringan tubuh.
Kata kunci: Sel, Struktur, Fungsi, Komunikasi Sel

The Hedgehog signalling pathway is crucial for development, adult stem cell maintenance, cell migration and axon guidance in a wide range of organisms. During development, the Hh morphogen directs tissue patterning according to a concentration gradient. Lipid modifications on Hh are needed to achieve graded distribution, leading to debate about how Hh is transported to target cells despite being membrane-tethered. Cytonemes in the region of Hh signalling have been shown to be essential for gradient formation, but the carrier of the morphogen is yet to be defined. Here we show that Hh and its co-receptor Ihog are in exovesicles transported via cytonemes. These exovesicles present protein markers and other features of exosomes. Moreover, the cell machinery for exosome formation is necessary for normal Hh secretion and graded signalling. We propose Hh transport via exosomes along cytonemes as a significant mechanism for the restricted distribution of a lipid-modified morphogen.

If Aristotle said : Man is a Speaking Animal , I try to define a Man as A group of Cells Talking New Media Language , through the exchange of many of the messages and signals, transmissions and receptions, just as is happening in social networks .
But New Media Language isn't , only , all this applications like Facebook , twitter , g+ .. , it's mean to Give each member of this world the freedom and opportunity , to communicate with other ,and Through this interaction and communication and sharing , can occur many changes in society , exactly as happens in the Cells Communication , That contact between them can make a number of physiological changes on the human body