Cell signaling and transcription factor genes expressed during whole body regeneration in a colonial chordate

<p>Abstract</p> <p>Background</p> <p>The restoration of adults from fragments of blood vessels in botryllid ascidians (termed whole body regeneration [WBR]) represents an inimitable event in the chordates, which is poorly understood on the mechanistic level.</p> <p>Results</p> <p>To elucidate mechanisms underlying this phenomenon, a subtracted EST library for early WBR stages was previously assembled, revealing 76 putative genes belonging to major signaling pathways, including <it>Notch/Delta</it>, <it>JAK/STAT</it>, protein kinases, nuclear receptors, Ras oncogene family members, G-Protein coupled receptor (GPCR) and transforming growth factor beta (TGF-β) signaling. RT-PCR on selected transcripts documented specific up-regulation in only regenerating fragments, pointing to a broad activation of these signaling pathways at onset of WBR. The followed-up expression pattern of seven representative transcripts from <it>JAK/STAT </it>signaling (<it>Bl-STAT</it>), the Ras oncogene family (<it>Bl-Rap1A, Bl-Rab-33</it>), the protein kinase family (<it>Bl-Mnk</it>), <it>Bl-Cnot</it>, <it>Bl-Slit </it>and <it>Bl-Bax inhibitor</it>, revealed systemic and site specific activations during WBR in a sub-population of circulatory cells.</p> <p>Conclusion</p> <p>WBR in the non-vertebrate chordate <it>Botrylloides leachi </it>is a multifaceted phenomenon, presided by a complex array of cell signaling and transcription factors. Above results, provide a first insight into the whole genome molecular machinery of this unique regeneration process, and reveal the broad participation of cell signaling and transcription factors in the process. While regeneration involves the participation of specific cell populations, WBR signals are systemically expressed at the organism level.</p

Spatial homogeneity of bacterial and archaeal communities in the deep eastern Mediterranean Sea surface sediments

The diversity of microorganisms inhabiting the deep sea surface sediments was investigated in 9 stations (700-1900 m depth) in the Levantine basin by 454 massive tag sequencing of the 16S rDNA V4 region using universal primers. In total, 108,811 reads (an average of 10,088 per sample) were assigned to 5014 bacterial and 966 archaeal operational taxonomic units (OTUs; at 97% cut off). The 55% of the reads were of archaea, indicating dominance of archaea over bacteria at eight of the stations. The diversity and estimated richness values were high (e.g., H&acute; ranged from 5.66 to 7.41 for bacteria). The compositions of the microorganisms at all stations were remarkably similar, with Bray-Curtis similarities of 0.53&ndash;0.91 and 0.74&ndash;0.99 for bacterial and archaeal orders respectively. At two stations, very high abundances of only a few genera (Marinobacterium, Bacillus, Vibrio, Photobacterium) were accountable for the dissimilarities documented compared to the other deep sea stations. Half of the bacterial reads (51%) belonged to the phylum Proteobacteria, comprising mainly Gammaproteobacteria (41&ndash;72% of the proteobacterial reads per sample), Deltaproteobacteria (12&ndash;29%), Alphaproteobacteria (7&ndash;18%) and Betaproteobacteria (3&ndash;14%). The most abundant bacterial family was Sinobacteraceae (order Xanthomonadales) with 5&ndash;10% of total bacterial reads per sample. Most abundant reads (15.4% of all microbial reads) were affiliated with Marine Group 1 archaea, putatively capable of ammonia oxidation (213 OTUs), and bacteria involved in nitrification were found in all samples. The data point to the significant role that chemolithotrophic carbon assimilation and nitrification fill in the oligotrophic deep sea Levant sediments. [Int Microbiol 19(2): 109-119 (2016)]Keywords: deep sea sediments &middot; eastern Mediterranean &middot; microbial communities &middot; ammonia oxidizing Archaea (AOA) &middot; Israe

Critical Evaluation of Branch Polarity and Apical Dominance as Dictators of Colony Astogeny in a Branching Coral

The high morphological resemblance between branching corals and trees, can lead to comparative studies on pattern formation traits, best exemplified in plants and in some cnidarians. Here, 81 branches of similar size of the hermatypic coral Stylophora pistillata were lopped of three different genets, their skeletons marked with alizarin red-S, and divided haphazardly into three morphometric treatment groups: (I) upright position; (II) horizontal position, intact tip; and (III) horizontal position, cut tip. After 1 y of in-situ growth, the 45 surviving ramets were brought to the laboratory, their tissues removed and their architectures analyzed by 22 morphological parameters (MPs). We found that within 1 y, isolated branches developed into small coral colonies by growing new branches from all branch termini, in all directions. No architectural dissimilarity was assigned among the three studied genets of treatment I colonies. However, a major architectural disparity between treatment I colonies and colonies of treatments II and III was documented as the development of mirror structures from both sides of treatments II and III settings as compared to tip-borne architectures in treatment I colonies. We did not observe apical dominance since fragments grew equally from all branch sides without documented dominant polarity along branch axis. In treatment II colonies, no MP for new branches originating either from tips or from branch bases differed significantly. In treatment III colonies, growth from the cut tip areas was significantly lower compared to the base, again, suggesting lack of apical dominance in this species. Changes in branch polarity revealed genet associated plasticity, which in one of the studied genets, led to enhanced growth. Different genets exhibited canalization flexibility of growth patterns towards either lateral growth, or branch axis extension (skeletal weight and not porosity was measured). This study revealed that colony astogeny in S. pistillata is a regulated process expressed through programmed events and not directly related to simple energy trade-off principles or to environmental conditions, and that branch polarity and apical dominance do not dictate colony astogeny. Therefore, plasticity and astogenic disparities encompass a diversity of genetic (fixed and flexible) induced responses

Anthropogenic impacts on coral reefs and their effect on fishery of Kilwa District, Tanzania

Tanzanian fishing coastal communities live on fishing activities as one their major economic activities, practicing fishing on shallow coral reefs areas whereby about 70% of fishery is artisanal. Improper use and overexploitation of fishery resources have resulted in damaging the coral reefs and the subsequent low quality catches. This study aimed at examining the impacts of coral reef fishery decline on rural livelihoods with an emphasis on food insecurity, alternative capabilities and activities on coastal communities of Kilwa district, Tanzania. Data collection methodology included household questionnaire survey, key informant interviews, participant observation and photographing. The survey was based on a sample of 90 households, randomly selected from three villages. The findings attest for a gradual reduction in fish catches over time, brought about by natural and anthropogenic impacts. Overfishing,use of illegal and destructive fishing methods, as well as extreme weather conditions, all threaten the sustainability of marine resources, particularly coral reef fishery that constitutes an important source of food and  livelihood. Following the results and as a way of lessen the current pressure on marine resources and diversifying livelihood capabilities we recommend introduction of mariculture and modern farming technologies especially on green vegetables on farms that can potentially be irrigated. The study further recommends establishment of a marine protected area and; in addition, the need to promote educational programs on  environmental and resources uses as well as application of active  restoration protocols for damaged coral reefs.Key words: Songo songo, Kivinje, Songo mnara, livelihoods, coral bleachin